# Food Additives Permitted for Direct Addition to Food for Human Consumption; Olestra > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A96-1584 ## Record - **Collection:** Federal Register - **Document type:** Rule - **Published:** January 30, 1996 - **Citation:** 61 FR 3118 ## Text SUMMARY: The Food and Drug Administration (FDA) is amending the food additive regulations to provide for the safe use of sucrose esterified with medium and long chain fatty acids (olestra) as a replacement for fats and oils. This action is in response to a petition filed by the Procter & Gamble Co. DATES: The regulation is effective January 30, 1996. Submit written objections and requests for a hearing by February 29, 1996. Submit written comments on the labeling requirement (Sec. 172.867(c)) by April 1, 1996. The Director of the Office of the Federal Register approves the incorporations by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 of certain publications at 21 CFR 172.867, effective January 30, 1996. ADDRESSES: Submit written objections to the Dockets Management Branch (HFA-305), Food and Drug Administration, 12420 Parklawn Dr., rm. 1-23, Rockville, MD 20857. FOR FURTHER INFORMATION CONTACT: Helen R. Thorsheim, Center for Food Safety and Applied Nutrition (HFS-216), Food and Drug Administration, 200 C St. SW., Washington, DC 20204, 202-418-3092. SUPPLEMENTARY INFORMATION: Table of Contents I. Introduction A. Safety Testing--Background 1. Legal Context of the Safety Evaluation 2. Dietary Context of the Safety Evaluation B. Toxicological Studies--Overview C. Nutritional Impact Studies--Overview D. GI Effects--Overview E. FDA's Decision Process II. Identity and Use A. Manufacturing Processes B. Constituents C. Specifications D. Stability E. Use and Intended Technical Effect F. Estimated Daily Intake for Olestra (EDI) III. Toxicity Data--Discussion and Evaluation A. Absorption, Distribution, Metabolism, and Elimination. 1. Rat Studies 2. Guinea Pig Studies 3. Mini-Pig Studies B. Genetic Toxicity Studies C. Animal Toxicity Studies 1. Teratogenicity studies 2. Subchronic and chronic feeding studies a. Ninety-day subchronic olestra feeding study in rats b. Two-year carcinogenicity studies in rats c. Two-year chronic toxicity and carcinogenicity studies in mice d. Dog feeding studies D. Toxicology summary IV. Effect of Olestra on Absorption of Drugs A. Effect of Olestra on the Absorption of Selected Lipophilic Drugs (EC-40) B. Effect of Olestra on the Absorption of Selected Lipophilic Drugs (EC-41) C. Effect of Olestra on Drug Bioavailability (EC-42) D. Effect of Olestra on the Systemic Levels of Steroidal Hormones in Women Taking Oral Contraceptives (EC-51) E. Summary V. Nutritional Studies A. Issues Associated with Olestra B. Effects of Olestra on Fat-Soluble Vitamins 1. Primary Human Studies a. Eight-week DR study design b. Eight-week VR study design c. Results and conclusions from primary human studies i. Vitamin A ii. Vitamin E iii. Vitamin D iv. Vitamin K v. Carotenoids 2. Other Human Studies a. Six-week vitamin D/K study b. Sixteen-week vitamin E study c. Vitamin A/Fat Study 3. Pig Studies a. Study design of the 12-, 26-, and 39-week studies i. Twelve-week DR Study ii. Twelve-week VR Study iii. Twenty-six week DR/VR Study iv. Thirty-nine week VR Study b. Study design of the 4-week DC study c. Results and conclusions from pig studies i. Vitamin A ii. Vitamin E iii. Vitamin D a. Petitioner conclusions b. FDA Conclusions iv. Vitamin K 4. Overall Conclusions Regarding Olestra's Effects on Fat-Soluble Vitamins a. Consumption scenarios b. Vitamin A c. Vitamin E d. Vitamin D e. Vitamin K i. Petitioner conclusions ii. FDA conclusions f. Carotenoids i. Data and information regarding carotenoids ii. FDA's evaluation of olestra's effects on carotenoids C. Effects of Olestra on Water-Soluble Nutrients that are Hard-to- Absorb or Limited in Diet 1. Results and Conclusions from Human Studies a. Vitamin B12 b. Iron c. Folate d. Zinc 2. Results and Conclusions from Pig Studies a. Vitamin B12 b. Iron c. Folate d. Zinc- e. Calcium 3. Overall Conclusions Regarding Olestra's Effects on Water-Soluble Nutrients a. Vitamin B12 b. Folate and Iron c. Zinc d. Calcium VI. Effect of Olestra on the Gastrointestinal (GI) Tract A. Introduction B. Effect of Olestra on GI Symptoms 1. Study of GI Symptoms in 8-week Studies in Normal Subjects a. Petitioner's evaluation of GI symptoms b. FDA's evaluation of the GI symptoms 2. GI Symptoms in the Oil Loss Study a. Effect of olestra stiffness on passive oil loss b. Effect of olestra stiffness on OIT c. Effect of olestra stiffness on GI symptoms 3. Study of Selected Fecal Parameters in Subjects Consuming Olestra a. Study design b. Petitioner conclusions C. FDA Conclusions 4. Study in Patients with Inflammatory Bowel Disease 5. GI Symptoms in Young Children C. Effect of Olestra on Intestinal Microflora Metabolism 1. Effect of Olestra on Breath Gas and Microflora-Associated Characteristics 2. Potential for Intestinal Microflora to Metabolize Olestra D. Effect of Olestra on Bile Acid Metabolism E. Overall Conclusions on Effects on the GI Tract [[Page 3119]] VII. Labeling of Foods Containing Olestra A. Labeling Authority B. Labeling with Respect to GI Effects C. Labeling with Respect to Effects on Nutrients D. FAC Discussions Regarding Labeling 1. GI Effects 2. Fat-Soluble Vitamins and Carotenoids E. Agency Conclusions Regarding Labeling of Foods Containing Olestra VIII. Response to Comments A. Comments on Procedures B. Substantive Comments IX. Environmental Impact Considerations X. FDA's Overall Conclusions XI. Administrative Record and Inspection of Documents XII. Objections XIII. References I. Introduction Olestra, also called sucrose polyester, is the common name for a mixture of substances formed by chemical combination of sucrose with six, seven, or eight fatty acids. The fatty acids, bound to sucrose by ester bonds, are of the type commonly found in edible oils and fats. Olestra has physical properties similar to those of natural fats. Olestra's particular physical properties depend on the specific fatty acids used and the degree of esterification. The Procter & Gamble Co., 6071 Center Hill Rd., Cincinnati, OH 45224-1703 (the petitioner), submitted a petition to FDA on April 15, 1987, for the use of olestra in shortenings and oils as a calorie-free replacement for fats and oils. The petition (FAP 7A3997) was filed on May 7, 1987. In a notice in the Federal Register of June 23, 1987 (52 FR 23606), FDA announced that the food additive petition had been filed by Procter & Gamble, proposing the issuance of a food additive regulation providing for the safe use of sucrose esterified with medium and long chain fatty acids as a replacement for fats and oils. On July 6, 1990, the petitioner amended the petition to limit the intended use of olestra to a 100 percent replacement for conventional fats in the preparation of savory snacks (i.e., snacks that are salty or piquant but not sweet, such as potato chips, cheese puffs and crackers). During the course of the petition evaluation, the petitioner also amended the proposed specifications that describe the additive. In the Federal Register of October 17, 1995 (60 FR 53740), FDA announced that a public meeting of the agency's Food Advisory Committee (the FAC) and a working group of the FAC would be held on November 14 through 17, 1995. The working group was asked to discuss and comment on whether all relevant issues associated with olestra had been addressed (Ref. 1). The discussion covered all aspects of the safety review of olestra, including nutrient effects and compensation, gastrointestinal effects, and labeling (Ref. 2\1\). \1\The transcript of the Olestra Working Group and full Food Advisory Committee meetings are provided as reference. Throughout the preamble to this final rue, reference is made to comments of Committee members and presenters to the Committee; footnotes indicate the transcript volum and page numbers of these. The affiliation and credentials of the commenter are also described. --------------------------------------------------------------------------- In the Federal Register of November 16, 1995 (60 FR 57586), FDA announced that it would consider public comments on the petition, including comments on the proceedings before the FAC, only if filed on or before December 1, 1995. This action allowed the agency to identify precisely which data and information to consider in making its decision on the petition. This measure was necessary to facilitate the agency's decision making process and to come to closure on the petition. By letter dated December 8, 1995, FDA extended to December 21, 1995, the time by which such comments could be submitted. This extension was in response to a request of the Center for Science in the Public Interest (CSPI).\2\ \2\On October 25, 1995, CSPI submitted a comment to the olestra petition entitiled ``White Paper on Olestra'' (the White Paper). (CSPI subsequently submitted revised versions of the White Paper on November 2 and 3, 1995.) The November 3, 1995, White Paper was provided to the Olestra Working Group and FAc members for consideration at the meetins of November 14-17, 1995 (Ref.3). In addition, the authors of the White Paper, Drs. Myra Karstadt and Michael Jacobson, presented data from the White Paper on all of the issues covered in the White Papers, namely, (1) consumption estimates, (2) effect of olestra on carotenoids, (3) effect of supplementation of olestra with vitamin K on coumadin therpay, (4) effect of olestra on GI symptoms, and (5) animal carcinogenicity studies. --------------------------------------------------------------------------- A. Safety Testing-Background 1. Legal Context of the Safety Evaluation Section 409 of the act (21 U.S.C. 348), sets forth the statutory requirements for approval of a food additive (21 U.S.C. 321(s)). With the enactment of the Food Additives Amendment of 1958 (the Amendment), Congress established a premarket approval system whereby the company seeking to market a food additive must first obtain approval from FDA. Through this mechanism, Congress sought to shield the public from unsafe or potentially unsafe products. Under section 409(c)(3) of the act, 21 U.S.C. 348(c)(3), FDA is not to approve a food additive petition ``* * * if a fair evaluation of the data before the Secretary\3\ * * * fails to establish that the proposed use of the food additive, under the conditions of use to be specified in the regulation, will be safe * * *. This provision is commonly referred to as the ``general safety clause.'' \3\This decision has been delegated to the Commissioner of Food and Drugs, 21 CFR 5.10(a)(1). --------------------------------------------------------------------------- By requiring that the data concerning a food additive ``establish'' safety, Congress squarely placed the burden of proving safety on the sponsor of a food additive petition, in this case Procter & Gamble. FDA need not prove that the additive is unsafe in order to deny approval. The term ``safe'' is not defined in the act itself. The legislative history of the Amendment makes clear, however, that a demonstration of absolute harmlessness is not required to sustain the approval of a food additive: Safety requires proof of a reasonable certainty that no harm will result from the proposed use of an additive. It does not-- and cannot--require proof beyond any possible doubt that no harm will result under any conceivable circumstance. This was emphasized particularly by the scientific panel which testified before the subcommittee. The scientists pointed out that it is impossible in the present state of scientific knowledge to establish with complete certainty the absolute harmlessness of any chemical substance. H. Rept. No. 2284, 85th Cong., 2d sess. 4-5 (1958). Accord: S. Rept. No. 2422, 85th Cong., 2d sess. 2 (1958). FDA regulations incorporate the concept of safety articulated in the Amendment's legislative history. 21 CFR 170.3(i). (``Safe'' means that ``* * * there is a reasonable certainty in the minds of competent scientists that the substance is not harmful under the intended conditions of use.'') Although the concept of ``harm'' is central to the act's safety standard, neither the statute, nor regulations implementing the food additive provisions, define harm. Once again, however, congressional intent is clear from the legislative history of the amendment. Specifically, ``harm'' means the capacity to injure or otherwise damage the health of individuals consuming the additive.+ The concept of safety used in this legislation involves the question of whether a substance is hazardous to the health of man or animal. H. Rept. No. 2284, 85th Cong., 2d sess. 4 (1958). See also Letter from Assistant Secretary of Health, Education, and Welfare Elliot L. Richardson to Congressman Lister Hill, Chairman, [[Page 3120]] Senate Committee on Labor and Human Resources, dated July 29, 1958. (``* * * in our opinion the bill is aimed at preventing the addition to the food our people eat of any substances the ingestion of which would expect to produce not just cancer but any disease or disability.'') The concept of harm was discussed during the Olestra Working Group and FAC meetings. One FAC member expressed the opinion that he would consider an effect that is undesirable as harmful or adverse\4\. However, the legislative history reflects that an effect is harmful if it affects health, not if it is simply an undesirable or unexpected effect that has no adverse health consequences. \4\Statement of Dr. Dennis Hsieh. Dr. Hsieh is a professor of environmental toxicology at the University of California at Davis. Transcript of the November 14 to 17, 1995, meeting of FAC (hereinafter Transcript), vol. 3, p. 40. --------------------------------------------------------------------------- The statute leaves the methods and criteria for interpreting data up to the discretion and expertise of the agency. Congress did, however, direct FDA to consider the following three factors: (A) The probable consumption of the additive and of any substance formed in or on food because of the use of the additive; (B) The cumulative effect of such additive in the diet of man or animals, taking into account any chemically or pharmacologically related substance or substances in such diet; and (C) Safety factors which in the opinion of experts qualified by scientific training and experience to evaluate the safety of food additives are generally recognized as appropriate for the use of animal experimentation data. (21 U.S.C. 348(c)(5).) In the case of olestra, the product's broad marketing potential and expected consumption by persons of all ages, including children, are aspects that have been considered in the safety evaluation. Importantly, Procter & Gamble is not required to show, nor is FDA permitted to consider, that olestra has benefits, health or otherwise, for consumers of the additive. Again, the legislative history of the Amendment is clear on this point. The question of whether an additive produces such [a technical] effect (or how much of an additive is required for such an effect) is a factual one, and does not involve any judgement on the part of the Secretary of whether such effect results in any added 'value' to the consumer of such food or enhances the marketability from a merchandising point of view. S. Rept. No. 2422, 85th Cong., 2d sess. 7 (1958). Accord: H. Rept. No. 2284, 85th Cong., 2d sess. 6 (1958). In summary, the general safety clause places on Procter & Gamble the burden of proving that a fair evaluation of the data in the administrative record establishes that there is a reasonable certainty that olestra will not be harmful under the prescribed conditions of use. Only if Procter & Gamble meets this burden can the food additive be approved. 2. Dietary Context of Safety Evaluation Olestra presents a different set of safety issues compared to most food additives. For example, most substances can induce toxic effects provided that the dose administered is sufficiently high. The primary purpose of most safety testing is to determine the toxic dose and to evaluate whether there is a sufficient margin of safety between the highest dose that is not toxic and the expected human exposure. Because olestra is intended to substitute for fat, a substantial component of the diet, it is difficult, if not impossible, to feed olestra to laboratory animals in amounts sufficiently high to allow use of the 100-fold safety factor that is commonly used to ensure safety (21 CFR 170.22), when evaluating animal studies. The use of a safety factor is intended to account for the uncertainty of extrapolating from toxicity data from animals to humans. (See 21 U.S.C. 348(c)(5)(c).) FDA concludes that in the case of the olestra petition, the agency is justified in not using the 100-fold safety factor for the following reasons. First, no toxic effects from olestra consumption were observed when olestra was fed atpara.levels up to 10 percent of the diet of laboratory animals (as discussed in section III. of this document). Second, olestra is not appreciably absorbed by the body and the minuscule amount of material that is absorbed is metabolized to substances (sucrose and fatty acids) that are further metabolized normally in the body. Thus, no major component of olestra is available to produce a toxic effect. Finally, a significant number of human studies have been performed to assess the safety of olestra, which assessment may be performed without the need for a safety factor. The fact that olestra is not absorbed also means, however, that as food components are absorbed from the intestine, the amounts of olestra present in the intestine will become an increasingly larger fraction of the total intestinal contents. Thus, the safety issues for olestra are focused on effects in the intestine, including potential interference with absorption of nutrients. The petitioner completed the standard toxicological testing program to demonstrate safety for a direct food additive, as outlined in FDA's guidance on such testing (Ref. 4). However, to account for the possible variations in composition, effects on composition due to heating, and inherent difficulties in extrapolating from laboratory animals to humans, the initial animal tests have been supplemented with a variety of human and additional animal studies taking into account the properties of olestra. In fact, since the original petition was submitted inpara.1987, Procter & Gamble has submitted more than 50 additional safety studies for review. In 1992 and 1993, the pivotal safety studies with regard to nutritional effects from the petitioned use of olestra were submitted. B. Toxicological Studies--Overview The petition submitted to FDA consists of data and information from toxicity studies in several animal species, including the rat, mouse, dog, and rabbit. The toxicity data base includes a battery of three mutagenicity/genotoxicity tests; subchronic feeding studies in mice, rats, hamsters, and dogs; and reproduction/teratology testing in the rat and rabbit. To determine whether olestra affects the structure and function of the gastrointestinal (GI) tract, a series of absorption, distribution, metabolism, and elimination (ADME) studies were conducted in rats, mini-pigs, and guinea pigs. C. Nutritional Impact Studies--Overview The limited digestibility of olestra poses a number of nutrition issues, including olestra's effect on fat-soluble vitamins and whether these effects could be compensated for by the addition of an appropriate amount of the affected vitamins. As a result, the petitioner conducted several studies, including those listed below, in both pigs and humans. Procter & Gamble conducted studies in swine because they have a digestive system similar to humans and can be evaluated for nutrient stores in the liver and bone. Five of the studies that were carried out in swine are: (1) a 12-week dose-response study (the 12-week DR study) of olestra on the status of vitaminspara.A, D, E, and K, and on hard-to-absorb and limited-in-diet nutrients; (2) a 12-week vitamin restoration study (the 12-week VR study) to determine levels of vitamins A, D, and E needed to offset olestra effects; (3) a 26-week dose-response and vitamin restoration study (the 26-week DR/VR study) to extend [[Page 3121]] the findings of the 12-week DR and 12-week VR studies to longer times and lower olestra intake levels; (4) a 39-week study (the 39-week VR study) to confirm the effects of 0.25 percent olestra and added vitamin A and E measured in the 26-week DR/VR study over a longer exposure time; and (5) a 4-week dietary context study (the 4-week DC study) to compare olestra's effects on vitamins A and E when olestra is consumed either with the diet or between meals. Procter & Gamble conducted studies of olestra in humans to eliminate any uncertainty related to extrapolating from pigs and to obtain subject reports on gastrointestinal effects. Those objectives were pursued in several human studies including: Two clinical studies, two studies in free-living subjects,\5\ and one short-term study designed to assess olestra's effect on vitamin A and fat absorption (the vitamin A/fat study). The two human clinical studies were an 8- week study to determine the dose response of olestra on the status of vitamins A, D, E, and K, and on hard-to-absorb and limited-in-diet nutrients (the 8-week DR study) and an 8-week study to confirm the compensation levels for vitamins A and E (the 8-week VR study). The free-living studies were a 16-week study to assess the status of vitamin E in subjects consuming 18 grams/day (g/d) olestra (the 16-week vitamin E study) and a 6-week study to determine the effect of 20 g/d olestra on vitamins D and K (the 6-week vitamin D/K study). \5\Free-living subjects maintain their normal diets and eating patterns except for consumption of the test article as instructed. --------------------------------------------------------------------------- D. GI Effects--Overview The petitioner performed several studies to evaluate olestra's effects on the gastrointestinal (GI) tract including the following. The two clinical studies (the 8-week DR and 8-week VR studies) were used to evaluate adverse gastrointestinal effects as reported by the test subjects. In addition, the effect of olestra on intestinal microflora was measured by conducting a breath gas expiration study. Several studies were also conducted to evaluate olestra's effects on bile acid metabolism and absorption. In order to determine olestra's effects, if any, in an at-risk population, studies were conducted in inflammatory bowel disease patients. Because some drugs are lipophilic (fat-soluble) and may partition into (i.e., be partially absorbed by) olestra, olestra's potential to affect absorption of drugs was also investigated. In addition, because nonabsorbable liquid oil can separate from other fecal material in the colon and leak through the anal sphincter, a human clinical study was performed to determine the relationship between olestra's stiffness and passive oil loss. E. FDA's Decision Process In light of the novel issues raised by the review of the olestra data, FDA's Center for Food Safety and Applied Nutrition (CFSAN) determined that it would be valuable to obtain additional expertise in resolving certain issues that had been raised. A Regulatory Decision Team (RDT) composed of senior FDA managers was established for the purpose of recommending, to the Director of CFSAN, a decision on the olestra food additive petition. In addition, FDA retained the services of several scientific consultants from outside the agency to facilitate the agency's deliberations. As is the case with all food additive petitions, the olestra data were reviewed by staff scientists. Because of the large number of studies and the diverse nature of the information, each of these scientists reviewed a portion of the total body of data on the additive, focusing on his particular area of expertise. These staff- level reviews, including any questions or issues raised by such reviews, were subsequently considered by the RDT, assisted by the outside consultants. In the RDT deliberations, an overall Center position on olestra's safety was synthesized; in the process, issues raised by individual reviewers were resolved, were determined to be not significant, or were incorporated into the synthesized position. During this deliberative process, the members of the RDT weighed the various pieces of scientific information and applied their scientific judgement as they developed an overall Center position. After the conclusion of the RDT deliberations and the meetings with consultants from outside the agency, FDA convened a public meeting of its FAC and a special Olestra Working Group of the FAC on November 14 through 17, 1995, to undertake a scientific discussion of the agency's evaluation of the safety data in the petition. The membership of the standing Committee was supplemented with temporary members and consultants to the Committee, representing scientific disciplines appropriate to the evaluation of a macro-ingredient fat substitute. At the Olestra Working Group meeting, Procter & Gamble presented a summary of the data it considered adequate to establish the safety of olestra, the experts with whom the agency had consulted presented their views on the sufficiency of the information to assess the safety of olestra, interested members of the public presented their opinions and evaluations of the data, and FDA presented its evaluation of the data. The Committee was asked to assess, in light of the state of the science relative to macro food ingredients, whether all critical safety issues with respect to the use of olestra in savory snack foods had been addressed. As set out in detail below, having completed its evaluation of the data in the petition and having considered the deliberations of the Olestra Working Group and the FAC, including all presentations to the Committee, and the comments received on the petition, the agency is amending the food additive regulations to permit the use of olestra in place of fats and oils in prepackaged ready-to-eat savory snacks. II. Identity and Use Olestra is the common name for the mixture of sucrose esters formed from the addition of six, seven, or eight fatty acids to the available eight free hydroxyl moieties of sucrose. Saturated and unsaturated fatty acids of chain length C12 to C20 and higher can be used to manufacture olestra. The final product is defined by specifications which include the fatty acid composition.- The identity of sucrose octaester as the principal component of olestra has been verified by infrared, mass, and nuclear magnetic (proton and 13carbon) spectrometry (Ref. 5). The generalized structure for olestra is set forth below. BILLING CODE 4160-01-F [[Page 3122]] [GRAPHIC][TIFF OMITTED]TR30JA96.000 BILLING CODE 4160-01-C [[Page 3123]] A. Manufacturing Processes Olestra is prepared by the addition of medium- and long-chain fatty acid methyl esters to sucrose in the presence of catalysts. The postsynthesis purification steps are the same as those generally practiced in the edible oils industry. These purification steps depend upon physical separations and do not involve chemical bond rearrangement or the use of solvents or catalysts. The methyl esters used to prepare olestra can be obtained by procedures common in the food industry such as the reaction of refined triglyceride oils with methanol in the presence of sodium methoxide or from esterification of their fatty acids. The resulting esters are washed with water to remove residual methanol, dried under vacuum, and distilled. The fats and oils can be derived from a variety of edible sources such as, but not limited to, soybean, palm, coconut, fully hydrogenated rapeseed, and cottonseed. Sucrose and the methyl esters are mixed with an alkali metal soap of a long-chain fatty acid. A small amount of transesterification catalyst such as an alkali metal (sodium or potassium) carbonate, bicarbonate, hydride, or alkoxide is added and the mixture heated under vacuum to withdraw the volatile methanol byproduct. Following the reaction, excess methyl esters and free methanol are removed by evaporation under vacuum. Standard steam deodorization removes free fatty acids and odors. Different lots of olestra may be mixed to achieve desired properties or to meet product specifications. The manufacture of olestra can be well controlled, based upon the petitioner's analysis of representative lots (Ref. 5). B. Constituents The principal trace constituents of olestra are collectively identified as the unsaponifiable fraction, ranging in concentration from 0.08 percent to 0.3 percent. These constituents are primarily aliphatic hydrocarbons and plant sterols that naturally arise from the edible triglyceride sources of fatty acids used in the synthesis of olestra. In this respect, these trace constituents of olestra do not differ from those found in typical edible oils. Additionally, difatty ketones (DFK's), formed during its manufacture, are found as trace constituents in olestra as consumed. DFK's form in olestra during the alkaline rearrangement manufacturing process. The DFK's that are present in olestra are a family of compounds with a common general structure consisting of two fatty acid chains with a central keto group. They are formed from naturally occurring vegetable oil-derived fatty acids used to make olestra. The length and degree of unsaturation of the fatty acid chains are determined by the source oil used to make olestra. Quantitative analysis of olestra by gas chromatography and mass spectrometry of 15 typical lots of olestra determined that olestra contains 36 to 416 parts per million (ppm) DFK's. The potential DFK range of olestra was altered to 100 to 300 ppm when the method of manufacture was updated. Qualitative analysis of soybean oil-based olestra showed that the DFK's ranged from 31 to 35 carbons in length, consistent with the predominance of C16 and C18 fatty acids in soybean oil. Identical analytical techniques showed that similar types (C29-C35 fatty acid chain length), but lower levels, of DFK are found in vegetables (5 to 86 ppm), cooked meat fat (0.15 to 2.73 ppm), and food-approved emulsifiers (10 to 55 ppm). Historically, the once-common commercial practice of rearranging fats and oils by base- catalyzed methods produced levels of DFK that exceeded 300 ppm. These results show that olestra is an additional dietary source of those DFK's that are now, and have been, commonly consumed in the food supply (Ref. 6). C. Specifications Olestra comprises a range of possible compositions that can be identified by a three-dimensional matrix defined by: (1) Fatty acid chain length; (2) the degree of fatty acid unsaturation; and (3) the distribution of full and partial esters of olestra. The petitioner has proposed specifications that include ranges for fatty acid chain length and degree of unsaturation to ensure functional products for use in savory snacks. The specified range of esterification ensures the nonabsorbable and noncaloric nature of the product. Traditional edible oil specifications that ensure purity and safety also are incorporated into the olestra specifications. These values include specifications for free fatty acid content, total methanol residues, water, residue on ignition, peroxide value, total heavy metal content, and lead. D. Stability Olestra is stable under ambient and high-temperature storage conditions. In all cases, olestra is at least as stable as triglycerides with similar fatty acid composition. Polymers form in both olestra and triglycerides during cooking, purification, or storage, when olestra or triglycerides are exposed to heat, moisture, and air. The polymers, comprised almost entirely of dimers and trimers, form by cross-linking at points of unsaturation on the fatty acid chains. This mechanism of cross-linking in olestra is the same as that which occurs in triglycerides. The amount of polymer found in olestra is less than that found in a conventional edible oil stored under identical, controlled conditions. Typical bulk lots of olestra were demonstrated to be as stable as triglycerides of similar fatty acid composition when stored at room and elevated temperatures (120 F) for up to 1 month. These olestra batches were found to be stable based upon the lack of significant change in fatty acid composition, ester distribution, free fatty acid levels, polymer levels, and oxidative stability (Ref. 7). Heating food fats in the presence of moisture and air results in the production of decomposition byproducts. Such byproducts are removed regularly from commercial cookers to maintain an effective frying system under good manufacturing practice. Use of olestra for frying savory snacks will similarly lead to production of byproducts. The petitioner conducted research to determine the extent of byproduct production from olestra compared to conventional frying fats, and to determine whether unique byproducts would be formed. A variety of analytical techniques were employed to characterize the profile of byproducts formed during the heating of olestra and conventional frying fats. The gross identity of the heated products was determined by standard methods such as fatty acid composition, carbon number profile, and peroxide value. In addition, comprehensive analyses of changes to the fatty acid side chains were undertaken. Fatty acids were methylated by transesterification, isolated by silica gel column chromatography or solid phase extraction, and analyzed by a variety of techniques including gas chromatography (GC), GC/mass spectrometry (MS), two-dimensional GC/MS, and high performance liquid chromatography (HPLC). This battery of tests provided an analytical sensitivity to detect a component present in the heated oil at a level of 17 ppm (equivalent to 0.05 ppm in the diet of 90th percentile consumers of olestra) (Ref. 8). For both olestra and conventional frying fats (triglycerides), the predominant chemical changes that occur under frying conditions are [[Page 3124]] oxidation reactions on the fatty acid side chains (Ref. 8). The principal byproducts of frying are polymers (dimers and trimers) which are joined primarily by bonds between unsaturated fatty acid components. Both olestra and conventional fats of similar fatty acid composition undergo a similar number of polymerization reactions under common heating conditions. For example, the amount of polymer increased 0.003 mole/100 g for olestra and 0.004 mole/100 g for a triglyceride of similar fatty acid composition. Levels of olestra and triglyceride polymers absorbed into the cooked foods under worst-case conditions are similar and show that there is no selective concentration in food. For example, polymer levels in food fried in either olestra or triglyceride ranged from 4 to 6 percent of total lipid weight. These values correspond to the concentration of olestra and triglyceride polymer in the bulk heated oil phases (Ref. 8). Baking conditions do not degrade olestra or triglyceride as readily as frying conditions, even though soda crackers commercially prepared with olestra may experience temperatures ranging from 250 to 350 deg.F. This is because crackers are exposed to such temperatures for only a few minutes (not hours), and the temperature within the body of the cracker can be expected to be substantially lower than the oven temperature. This stability in baking assessment was confirmed when both olestra and a triglyceride of similar fatty acid composition were used to prepare soda crackers, and the crackers were baked for 6 minutes at the more common commercial temperature of about 250 deg.F. The neat (i.e., prior to baking) olestra and triglyceride were analytically characterized, and the profiles compared to those obtained from the fats extracted after the soda crackers were baked. Unlike during frying, neither olestra nor the triglyceride formed any measurable polymer during the 250 F baking (Ref. 9.). Consistent with a lack of change in polymer content, results demonstrate that neither olestra nor the triglyceride experienced any significant change in primary structural composition (i.e., ester distribution for olestra; or the tri-, di-, or monoglyceride profile for the triglyceride). The only notable change in both olestra and the triglyceride was a slight increase in free fatty acid content. This latter effect is expected because free fatty acids may be present in the cracker raw ingredients, and the alkaline chemical leavening agents used in soda cracker production can promote ester hydrolysis. The similarity of changes in olestra and triglycerides during soda cracker baking is consistent with the fact that the chemical changes in both products take place on the fatty acids, and yield the same decomposition products. To test stability during storage after baking, both olestra and a triglyceride of similar fatty acid composition were used to make soda crackers, unflavored plain crackers, and unflavored snack crackers. All products were packed in air to reflect current market practice, aged under controlled temperatures and time to reflect common and worst-case storage conditions, and analyzed for parent, polymer, and decomposition products. The results demonstrate that the stability of olestra and triglyceride were comparable under the conditions studied (Ref. 9). FDA concludes that use of olestra in frying media for savory snacks results in neither more nor different byproducts of the frying process than currently experienced with conventional oils. Also, olestra is as stable as triglyceride in crackers during baking and in baked crackers stored under expected and worst-case conditions. E. Use and Intended Technical Effect Olestra is proposed for use as a calorie-free replacement for up to 100 percent of the conventional fats and oils used in the preparation of savory snacks such as flavored and unflavored chips and crisps, flavored and unflavored extruded snacks, and crackers. These uses include substitution for fat for frying as well as sources of fat in dough conditioners, oil sprays, and flavors. Olestra will function in savory snacks as a texturizer and as a formulation aid (21 CFR 170.3(o)) at levels not in excess of that reasonably required to produce its intended effect. F. Estimated Daily Intake for Olestra (EDI) When conducting a food additive safety evaluation, FDA typically uses estimated 90th percentile chronic intakes. The petitioner has provided a study of probable intake for olestra, completed by the Market Research Corporation of America (MRCA), that contains sufficient information to estimate both chronic and acute exposures to olestra. The MRCA methodology estimates the daily consumption of olestra from savory snacks for individuals by combining: (1) The individual's frequency of consumption of savory snacks; (2) the average amount eaten per eating occasion of that savory snack; and (3) the amount of olestra in that savory snack. Eating occasion frequencies were determined from 14-day dietary diaries that were kept by heads of household. The amount of food eaten per eating occasion was derived from the USDA's Nationwide Food Consumption Surveys. The amount of olestra in snacks was determined in the petitioner's laboratories. The MRCA survey data show that at the 90th percentile, the probable lifetime-averaged intake of olestra is 6.4 g/p/d. FDA believes however, that it is appropriate to consider energy needs in estimating the daily intake of olestra. Based on the assumption that consumers of olestra will compensate for calories ``lost'' due to consumption of olestra by increasing their intake of food (including olestra-containing snacks), the agency has concluded that the lifetime-averaged EDI for olestra should be increased by 10 percent to 7.0 g/p/d (Ref. 10). Any effects of olestra on nutrients or nutrient absorption could be exhibited during less than chronic exposure conditions. To evaluate sub-chronic conditions, FDA has estimated that a ``high'' acute consumer of olestra (every day for 12 weeks) would consume 20 g/p/d, equivalent to eating a 2-ounce (oz) bag of potato chips every day (Ref. 11). The MRCA survey information submitted by the petitioner shows that the 99th-percentile, 14-day average intake for olestra would be 14.8 g/ p/d (corrected to 16.3 g/p/d for caloric compensation) in the 18 to 44 year old male group. The 99th-percentile single-day intake of olestra for the group consuming the highest level of savory snacks (13 to 17 year old male group) is 40.4 g/p/d (corrected to 45 g/p/d). It is not likely that this high single day intake would be repeated every day in the 12-week time frame previously mentioned. In terms of consumption patterns, the MRCA data also show that approximately 9 percent of lunch and dinner meals include a snack food that could potentially contain olestra. The data also show that 63 percent of snack food eating occasions occur with a meal. Consumption estimates of olestra-containing savory snacks were discussed at the Olestra Working Group and FAC meetings. In particular, CSPI raised three concerns about these estimates. First, CSPI presented several consumption scenarios to the Olestra Working Group\6\ that the organization [[Page 3125]] asserted better represented expected olestra consumption. These consumption estimates ranged from 4.2 g/p/d to 37.5 g/p/d. CSPI's higher consumption estimates included an increase in consumption of olestra-containing snacks over full-fat snacks; this increase was based on the results of a telephone survey, which survey indicated that people think they would eat 25 percent more snacks if the snacks contained lower fat. Based on these scenarios, CSPI asserted that there would likely be a substantial number of snack eaters consuming olestra in quantities similar to those fed in the 8-week human studies (8, 20, and 32 g/d). \6\These CSPI comments were presented by Dr. Myra Karstadt, Ph.D. Transcript, vol. 2, p. 49. This information is also discussed in CSPI's White Paper (Ref. 3). --------------------------------------------------------------------------- Second, CSPI asserted that consumers usually eat an entire bag of chips at one sitting, and that bags marked ``single-serving'' typically contain from three-quarters of an ounce to 2 ounces. Therefore, CSPI claimed that in many cases, people would eat several ounces of chips at one sitting, and that, in evaluating olestra's for GI effects, it is important to consider single-sitting consumption levels. Third, CSPI expressed concern that the MRCA survey population may not represent the most vulnerable high-volume consumers of snack products, such as minority teenagers resident in low socioeconomic areas, who may both consume large quantities of savory snacks and have poor nutritional status. Dr. Gail Harrison, consultant to the petitioner,\7\ presented her analysis of the MRCA survey demographics to the Olestra Working Group, which responded to CSPI's third concern. Dr. Harrison stated that the MRCA survey population is very representative of the U.S. population in terms of regional census areas, census regions, and urbanization. Further, in terms of different population groups, she said that children of all ages are appropriately represented, while young homemakers are slightly underrepresented. In addition, there is a slight, though not statistically significant underrepresentation of minority households, and the income distribution slightly underrepresents highest-income and lowest-income households by about three to four percent. Also, information was provided to the Olestra Working Group by the petitioner from an analysis of USDA's 1990-1991 Continuing Survey of Food Intake that the average intake of salty snacks (crackers, popcorn, pretzels, and corn chips) by food-stamp recipients was about 4 g/p/d while nonrecipients consumed about 7 g/p/ d.\8\ \7\Dr. Gail Harrison, Professor, School of Public Health, University of California-Los Angeles. Dr. Harrison presented at the petitioner's request. Transcript, vol. 2, p. 73. \8\Information from testimony by Mr. Thomas Breaker from the Mathematica Policy Research Group before the Committee on Agriculture's Subcommittee on Department Operations and Nutrition (Transcript, vol. 2, p. 163). --------------------------------------------------------------------------- After presentations by the petitioner, CSPI, FDA, and others, the members of the Olestra Working Group generally agreed that all issues with regard to the chemistry and consumption of olestra had been adequately addressed. FDA agrees that it is appropriate to use conservative assumptions in the safety evaluation of olestra, the effect of which is likely to over-estimate consumption patterns. For this reason, FDA has assumed that 100 percent of all savory snacks will be replaced by olestra- containing snacks. That is, once olestra is approved, some consumers will eat only savory snacks containing olestra. FDA further believes that it is appropriate to rely on the MRCA survey data to estimate consumption because the survey is well designed, includes a large base of people, and a sound methodology in that the survey relies on food- intake diaries kept by participants rather than relying on participants' recall of what they ate sometime in the past. In light of the discussion before the Olestra Working Group, FDA further concludes that the MRCA survey data are sufficiently representative of the eating habits of the U.S. population and, in particular, that the eating patterns of low-income individuals are captured by the MRCA data and thus, such individuals are included in the agency's consumption estimates. In addition, FDA finds that a scenario-driven estimate of 20 g/p/d, based on consumption of 2 oz of chips per day, which is greater than the 99th percentile, 14-day average intake in the highest consuming group of snack eaters (18 to 44 year old makes), is a reasonable estimate of a ``short-term'' high consumer. FDA has not used the largest amount reported to have been eaten in one sitting during the MRCA survey period because that amount represents an extreme that is unlikely to be repeated for more than a few days. FDA further concludes that there are no scientific data to justify increasing the estimated olestra exposure derived from the MRCA survey in order to account for the potential consumers' increase in consumption of snacks because the snacks are low-fat. FDA has also evaluated the potential chronic exposure to DFK's formed from the manufacture of olestra. Mean DFK intake from olestra- prepared snacks is 0.4 mg/p/d (DFK level of 125 ppm). The 90th percentile for DFK's, based on an olestra intake of 7 g/p/d, is 0.87 mg/p/d. For perspective, the mean level of DFK in foods (primarily beef, chicken, pork, and the brassica vegetables) is 9 mg/p/d and the 90th percentile background exposure (typically approximately twice the mean for commonly consumed foods such as meat and vegetables) would be 18 mg/p/d (Refs. 12 and 13). Thus, FDA has determined that the available data and information support the use of 7 g/p/d olestra as an estimate of chronic consumption by the 90th percentile snack eater and 20 g/p/d olestra as an estimate of shorter term consumption. III. Toxicity Data--Discussion and Evaluation A. Absorption, Distribution, Metabolism, and Elimination The petitioner conducted a series of preliminary studies to assess the absorption of olestra in rats. In order to identify which organs might accumulate intact olestra or metabolize olestra if absorbed, rats were intravenously (IV) injected with olestra radiolabelled with 14C on the sucrose portion of the molecule. The radiolabelled olestra initially deposited in the liver and, to a lesser extent, in the spleen. The data in these early studies show that, olestra was taken up rapidly by the reticuloendothelial system and deposited in the liver and spleen within 3 days following intravenous injection. There was a minor accumulation in the fatty tissues with only a trace amount detected in expired air. At 21 days, the concentration of olestra in the liver dropped to about 50 percent of the 3-day level. Olestra was excreted unchanged via the biliary and fecal routes. These results demonstrate that the olestra that accumulated in the liver following intravenous injection was not metabolized because radiolabel was not accumulated in other tissues, which would have occurred if olestra had been hydrolyzed by hepatic enzymes. The absence of olestra's metabolization was confirmed by thin-layer chromatography, which showed intact olestra in the bile and feces. The half-life of olestra in the liver was about 5 days. Examination by electron microscopy of liver tissue from rats injected intravenously with olestra showed that, at 56 days after dosing, lipid accumulation was greatest in the Kupffer cells. By 84 days post-dosing, the greatest accumulation was in the parenchymal cells, indicating that both kinds of cells handle olestra following [[Page 3126]] iv administration. Tissue deposition studies were also conducted in rats fed one percent olestra for 30 days. Based on the data submitted, there was no significant radioactivity detected in the liver, spleen, lung, thymus, or adipose tissue from animals fed olestra. Procter & Gamble conducted a series of studies in male and female rats to determine the fate of penta-, hexa-, hepta- and octa-ester preparations of olestra administered by gavage. The livers were removed and lipid extracts were analyzed for the various esters. No esters were detected by thin layer chromatography. However, the overall sensitivity of the method was only approximately 2 to 3 percent of the administered dose. Therefore, any olestra in rat liver extracts containing less than 3 percent of the administered olestra ester preparations could not be detected. Additional fat balance studies conducted in the rat demonstrated that enzymatic hydrolysis can convert mono- through penta- ester formulations of olestra to sucrose and fatty acids while hexa- through octa-ester formulations are not absorbed (Ref. 14). To assess further the potential for olestra to be absorbed from the GI tract, the petitioner conducted a series of absorption studies in rats, guinea pigs, and mini-pigs. These studies used uniformly-labeled olestra with high specific activity and sensitive analytical methods to analyze tissues, especially liver, for intact olestra and urine for 14C-sucrose, a metabolic product that would result from the metabolism of any absorbed olestra. 1. Rat Studies In the rat studies, in order to detect the absorption of a very small amount of the administered dose, olestra of high chemical and radiochemical purity and high specific activity (1 millicurie/g) was dosed at high levels (0.1 millicurie/rat). Tissues were collected, combusted, and analyzed for radiolabelled CO2, or the lipid fraction was extracted and analyzed for intact olestra by HPLC. Urine, feces, expired CO2, and the carcass were analyzed for 14C. The urine was analyzed for 14C-sucrose to assess whether olestra had been absorbed and metabolized (Refs. 15 through 19). Five samples which represented the extremes, and beyond, of the olestra specification range, as well as a typical mid-range composition, were tested. This set of samples included the following: (1) a sample in which the fatty acid chains were 100 percent saturated; (2) a sample in which the fatty acid chains were highly (85 percent) unsaturated; (3) a sample rich in short-chain length fatty acids (59 percent) and penta- and hexa-esters (84 percent); (4) a sample which represented the unheated mid-range of the olestra specification; and (5) a mid-range olestra sample which was subjected to conditions of repeated thermal stress as would occur in the commercial preparation of savory snacks. Although the short-chain length fatty acids (59 percent) and penta- and hexaesters (84 percent) sample falls outside the olestra specifications proposed in the petition, the sample was tested to determine the absorption of these components that might occur in olestra in trace amounts. The mean recovery of unabsorbed radiolabel from the rat feces, GI tract and contents, animal wipes and animal rinse solutions, and cage wipes and cage rinse solutions was greater than 98.5 percent of the administered dose regardless of the radiolabeled olestra formulation studied (Ref. 19). This recovered amount represents olestra that is not absorbed. The recovery of absorbed radiolabel carbon from olestra ranged from 0.02 percent of the administered dose of the high saturated olestra formulation to 1.5 percent of the administered dose of the short chain length and low ester formulation. The majority of the absorbed radioactivity was found in the expired CO2 and urine. Analysis of liver lipids for intact olestra and urine for 14C-sucrose did not show any radiolabelled carbon. These data demonstrate that most of the ingested olestra remains intact and is not absorbed, but is excreted intact in the feces. The percent absorption of these olestra formulations are shown in Table 1 below. TABLE 1.--PERCENT ABSORPTION OF OLESTRA FORMULATIONS IN RAT ABSORPTION STUDIES -------------------------------------------------------------------------------------------------------------------------------------------------------- Olestra Composition Percent Absorbed -------------------------------------------------------------------------------------------------------------------------------------------------------- Low Chain/Low Ester.............................. 1.50 Mid-Range........................................ 0.16 Heated Mid-Range................................. 0.14 High Unsaturates................................. 0.05 High Saturates................................... 0.02 -------------------------------------------------------------------------------------------------------------------------------------------------------- The absorption measured for the sample rich in short-chain fatty acids and penta and lower esters was 1.5 percent of the administered dose. This higher value, compared to the other olestra formulations tested, resulted from the hydrolysis of the penta and lower esters to sucrose and free fatty acids in the GI tract. Sucrose molecules released by hydrolysis of the lower esters in the GI tract were further hydrolyzed by intracellular mucosal sucrase and passed into the portal system as the monosaccharides glucose and fructose. These molecules were metabolized normally and the radiolabel was excreted rapidly in expired air and urine. The only variable that significantly affected absorption was the lower chain length and lower degree of esterification. Restriction of these lower chain length and lower esters in olestra through specifications for the additive limits the absorption to less than 0.16 percent of the administered dose. Of the five radiolabelled olestra formulations studied in the rat, the heated mid-range formulation with 0.14 percent recovery of absorbed radiolabel represents the olestra formulation proposed to be marketed for human consumption. FDA concludes that the low level (0.14 percent) of absorbed radiolabelled carbon from penta- and lower esters contained in the heated olestra is biologically insignificant because the only components shown to be absorbed are metabolized to sucrose and fatty acids which are metabolized normally (Ref. 19). 2. Guinea Pig Studies The petitioner conducted studies in male and female poligeenan-fed guinea pigs to assess the potential for increased absorption of olestra across a damaged intestinal mucosa. (Poligeenan is known to cause intestinal damage.) Male and female guinea pigs were given 3 percent poligeenan in tap water, or tap water alone (controls), for 5 weeks until GI lesions similar to those seen in acute and chronic human GI diseases (such as ulcerative colitis and Crohn's disease) were induced. The guinea pigs were then dosed with 200 microcuries of a heated olestra and the absorption of [[Page 3127]] olestra was compared between animals with normal GI tracts and those with compromised GI tracts. The total recovery of radiolabelled olestra was greater than 97 percent of the administered dose for female guinea pigs in both the normal and compromised groups.\9\ The majority of radiolabel, 87 percent to 95 percent, was found in feces and GI contents. Guinea pigs in the compromised group had comparable amounts of radiolabel in the GI tract and contents compared to the normal group. In addition, there were no consistent differences between the normal and compromised groups in the distribution of the absorbed radiolabel among various tissues, blood, urine, or expired CO2. These findings show that the absorption of intact olestra is no greater in guinea pigs with compromised GI tracts than in guinea pigs with normal GI tracts (Refs. 20 and 21). \9\Incomplete collection of fecal material from support screens, sides and bottoms of cages, and fur of animals for male guinea pigs resulted in lower radiolabel recovery (88.1 percent) and greater variability in results than for female guinea pigs. --------------------------------------------------------------------------- 3. Mini-Pig Studies The absorption of a typical, mid-range heated olestra was determined in weanling mini-pigs. The weanling mini-pig was chosen because its GI tract is physiologically and anatomically similar to humans and, like man, the mini-pig can tolerate a high fat diet. The design for the mini-pig study was similar to the design in the rat absorption studies except that expired CO2 was not collected from the mini-pigs because metabolic cages large enough to house mini-pigs were not available at the contract laboratory. In addition, the dose of radiolabelled olestra was increased to 0.35 millicuries per mini-pig so that the detection limit was comparable to that in the rat studies. For both male and female mini-pigs, 98.9 percent of the recovered radiolabel was found unabsorbed in the feces, GI tract plus contents, and animal rinse solutions. No radiolabelled olestra was found in the lipid fraction that would have contained olestra, if present, in the lipids extracted from livers of the mini-pigs (Ref. 22). Overall, the results from these studies in rats, guinea pigs, and mini-pigs demonstrate that while a small percentage of the olestra formulation consisting of penta- and lower esters is absorbed and metabolized to fatty acids and sucrose, nearly all of the ingested olestra remains intact and is not absorbed (Refs. 19, 21, and 22). Heating does not significantly increase olestra absorption and absorption is no greater when the GI tract is compromised than when it is intact. B. Genetic Toxicity Studies The petitioner conducted a battery of genetic toxicity studies with the unheated mid-range olestra formulation. Olestra was not genotoxic in any of the following test systems: An Ames Salmonella test with or without metabolic activation, a mouse lymphoma cell mutagenicity assay with or without activation, an unscheduled DNA synthesis test, and a Chinese hamster ovary cell in vitro cytogenetics test with or without activation. Because of solubility problems with olestra in these early genetic toxicity studies, the petitioner conducted an additional battery of in vitro assays and in vivo cytogenetic studies on heated mid-range olestra with Pluronic F-68, a nontoxic, nonionic surfactant to ensure cell contact with olestra. No evidence of mutagenicity or genetic toxicity from heated olestra was observed in the following test systems: The Salmonella/mammalian microsome mutagenesis assay; the L5178Y TK +/- mouse lymphoma assay; the test for chemical induction of unscheduled DNA synthesis in rat hepatocytes; and the cytogenicity study in Chinese hamster ovary (CHO) cells. These tests were conducted in the presence and absence of liver enzyme (S-9) activation at concentrations of up to 5 mg/mL. In addition, there was no evidence of chromosomal aberrations from heated mid-range olestra observed following examination of the bone marrow in the in vivo cytogenicity assays (using both acute and chronic dosing protocols) conducted on Sprague-Dawley rats (Ref. 23). Based upon the foregoing result, FDA concludes that olestra is not genotoxic. C. Animal Toxicity Studies 1. Teratogenicity Studies The teratogenic potential of olestra was evaluated in studies conducted in the rat and rabbit. These studies establish that olestra was not teratogenic when fed during organogenesis in either species. Olestra was also not teratogenic nor did it affect reproduction in a multi-generation rat reproduction/teratology study. Olestra was fed to rats (10/group) at 3.2 percent, 6.4 percent, or 12 percent of the diet beginning on the 6th day of pregnancy. Dams were sacrificed on days 13 and 20 of pregnancy, and the fetuses examined for abnormalities. The uterine contents of rats killed on day 13 of pregnancy were evaluated for implantation, resorption sites, and the number of corpora lutea. The fetuses of the dams sacrificed on day 20 were removed and corpora lutea counted; the pups were sacrificed and evaluated for anomalies. One-third of the fetuses were cleared and stained for study of the skeleton, and two-thirds were sectioned for study of the soft tissues. This study provided no evidence that olestra is teratogenic or embryotoxic (Ref. 24). In a rabbit teratology study, heated olestra was administered via gavage at doses representing 1 percent, 5 percent, and 10 percent of the diet during the critical stages of gestation (days 6 to 19); control animals were dosed with distilled water. Dams were sacrificed on day 30 of pregnancy and the fetuses examined for abnormalities. This study provided no evidence that olestra was teratogenic (Ref. 25). For the multi-generation study, weanling rats were maintained on diets containing 0 percent, 1 percent, 5 percent, or 10 percent olestra for a 91-day growth period. The mid- and high-dose diets were supplemented with vitamin A (2.5 times the National Research Council (NRC) requirements\10\) and vitamin E (five times the NRC requirements), in order to compensate for the reduced absorption of these nutrients in the presence of olestra. At the end of 91 days, F0 dams were mated for a reproduction (F1A) phase and then were mated again for a teratology (F1B ) phase. After the growth period, the F1A offspring were mated for the F2A and F2B generations. Olestra had no effect on mating, conception, embryonic development, fetal and postnatal viability, or postnatal growth in either generation (Ref. 24). \10\NRC requirements are actually recommendations set at levels close to the amount required for good health in the subject animals. --------------------------------------------------------------------------- 2. Subchronic and Chronic Feeding Studies Early feeding studies in rats with unheated olestra at levels of 4 percent, 8 percent, or 15 percent of the diet for 28 or 91 days resulted in no deaths, no decrease in the absorption of triglycerides or protein, no differences in urine or blood chemistry, hematology, or gross or microscopic histopathology. These studies are not addressed further. a. Ninety-Day subchronic feeding study in rats. The petitioner conducted two subchronic toxicity studies in rats. The first subchronic olestra feeding study in rats showed no adverse effects but used unheated olestra. Therefore, the petitioner, conducted a second 90-day toxicity study in rats using olestra [[Page 3128]] that had been heat abused to a degree exceeding that likely to occur during the preparation of savory snacks. Specifically, olestra that had been heated for 7 days at 190 deg.C (representing an extreme heating condition) was fed to 6 groups of 40 rats each (20 rats per sex) at 0 percent, 0 percent, 1 percent, 5 percent, 10 percent, and 0 percent in rodent chow ad libitum for 90 days. Groups I and II were chow controls while Group VI control rats were maintained on a diet that contained 10 percent previously heated triglyceride. Diets for groups II-V were supplemented with vitamins A, D, and K (five times the NRC requirement); vitamin E was added to these four diets at 8.0 times, 0.8 times, 4.0 times, and 8.0 times the NRC recommended levels, respectively. The study included twice-daily observations and weekly physical examinations. Body weight, body weight changes, food consumption, and olestra intake were determined weekly. Ophthalmoscopic examinations were performed pretest and at study termination. Clinical chemistry, hematology, and urinalysis parameters were measured at study termination on 10 animals/sex/group. Complete gross postmortem examinations were performed on all animals at study termination. The brain, adrenals, ovaries, testes (with epididymides), kidneys, and liver were removed, weighed, and organ-to-body-weight and organ-to-brain-weight ratios were calculated. A full complement of tissues was examined histopathologically from all animals in Groups I, II, V, and VI surviving to study termination, and any animals in Groups III and IV dying unscheduled deaths. Lungs, liver, kidneys, and gross lesions were evaluated from Group III and IV animals surviving to study termination. Survival, physical condition, body weight, food consumption, feed efficiency, organ weight, organ-to-body weight ratios, hematologic parameters, and histomorphology were evaluated. Olestra fed rats compensated for the decrease in caloric intake due to olestra having zero calories by consuming more food than control rats. No adverse treatment-related effects were observed. These results establish that heated olestra is not-toxic when fed to rats at levels as high as 10 percent of their diet for a period of 90 days (Ref. 26). b. Two-year carcinogenicity studies in rats. Two 2-year carcinogenicity studies of olestra were conducted in rats. In the first study, Fischer 344 rats, 70 per sex per group, were fed olestra at levels of 0 percent, 1 percent, 5 percent, or 9 percent of the diet for 2 years with interim sacrifices at 12 and 18 months. In the second study, Fischer 344 rats, 50 males and 73 females per group, were fed olestra at 0 percent or 9 percent of the diet for 2 years with an interim sacrifice at 12 months. In both studies, diets were supplemented with five times the NRC recommended levels of vitamins A, D, E, and K, to offset the reduced absorption of fat-soluble vitamins in the presence of olestra. The diets in both studies also contained 2 percent fully hydrogenated palm oil to control passive oil loss (anal leakage). The studies included twice-daily observations, and weekly physical examinations. Body weight, body weight changes, food consumption, and olestra intake were determined weekly for the first 12 weeks and monthly thereafter. Feed efficiency was determined during the first 12 weeks. Ophthalmoscopic examinations were conducted pretest, and at scheduled sacrifice. Clinical chemistry, hematology, and urinalysis parameters were measured at 12 and 24 months. Complete gross postmortem examinations were performed on all animals. Selected organs were removed, weighed, and organ-to-body-weight and organ-to-brain- weight ratios were calculated for all rats surviving to scheduled sacrifice periods. Liver samples were taken from rats in the 9 percent olestra groups from both studies for analysis of olestra. Histopathological evaluations were conducted on a full complement of tissues from animals in the control and 9 percent olestra groups from both studies. Liver, pituitary gland, gross lesions, and tissue masses were evaluated for all animals on study. The duodenum, jejunum, ileum, cecum, and colon were examined for all animals sacrificed at 12, 18, and 24 months. Rats compensated for the caloric dilution of olestra by consuming more food than was consumed by the controls. Olestra had no effect on ophthalmology, organ weight, organ-to-body- and organ-to-brain-weight ratios, clinical chemistry, hematology, or urinalysis parameters. There was no evidence that intact olestra accumulated in the liver tissue of rats fed 9 percent olestra for 2 years. There were no treatment-related adverse effects on growth, longevity, or general health, and there were no treatment-related neoplastic responses or evidence of chronic toxicity in either study. In the first study, there were four instances in which differences between treated groups and controls required FDA pathologists to assess whether the effect was treatment-related: male survival, incidence of pituitary adenoma (males and females), mononuclear cell leukemia (males), and basophilic liver foci (females). FDA pathologists also evaluated the following differences in incidence in the second chronic rat study: Incidence of pituitary cysts (males), mineralization of the renal cortex and bile duct hyperplasia, and basophilic liver foci in females. The differences observed between treated groups and controls in both chronic studies are marginal. Pituitary adenomas are very common spontaneous tumors in Fischer- 344 rats with a tendency for highly variable background incidences (Ref. 27). The increased incidence of pituitary adenoma in both sexes in the first chronic rat study represent expected variations in spontaneous background incidences. Thus, FDA concluded that there was no association of the pituitary adenomas with olestra treatment. Likewise, FDA concludes that there was no association between the incidence of leukemia in male rats and treatment with olestra for several reasons. First, the possible association is not supported by the results of the second study in which there was no comparable development of leukemia. Second, the incidences in the first study, particularly the control group, are unusually low compared to historical data from the National Toxicology Program (NTP) data base and compared to the results of the second study (Ref. 27). Third, mononuclear cell leukemia in Fischer-344 rats is a common spontaneous disease in old age with considerable tendency for background variation (Ref. 27). Therefore, such differences in incidence are not unusual but rather are expected from the normal variation of spontaneous tumor incidences. In the first rat study, there was an increase in the number of olestra-treated female rats with basophilic liver foci at the 1 year interim sacrifice without any clear increase in the severity of this lesion at the end of 2 years. However, female groups including the terminal sacrificed animals as well as the unscheduled deaths, demonstrated no clear increase in the incidence of basophilic liver foci with olestra treatment. The same phenomenon of early occurrence of basophilic liver foci in olestra-fed female rats was observed in the second study. In both studies, the basophilic foci in the control and treated rats were similar morphologically. In presentations to the Olestra Working Group and the FAC, and in its White Paper, CSPI expressed concern about the significantly higher incidence of basophilic liver foci at the end of 12 months, although CSPI acknowledged [[Page 3129]] that the difference between control and treatment groups disappeared by 24 months. CSPI asserted that, although 24 months is the majority of a rat's lifetime, the study should have been carried out for the rats' entire lifetime because it is possible that the foci might have progressed to cancer. CSPI also recommended that an expert Committee (such as NTP review) the findings.\11\ \11\Transcript, vol. 2, p. 135. --------------------------------------------------------------------------- Based upon an examination of all of the data in both studies, FDA pathologists concluded that these findings represented normal biological variability in 24-month-old rats and were not related to olestra ingestion for the following reasons. First, the findings lacked a dose-response effect and were not observed in both male and female rats in both chronic studies (Refs. 28 and 29). Second, the spontaneous occurrence of basophilic liver foci is frequent and variable in aging Fischer-344 rats (Refs. 30 and 31) and the incidence can reach 100 percent at 2 years (Refs. 32 and 33). Further, the majority of foci do not become neoplasms. Third, the most recent studies indicate that hepatocarcinogens induce more morphologically variable foci than those observed spontaneously (Refs. 30, 34, and 35). Thus, the early occurrence and morphological similarity of the basophilic liver foci in the control and the olestra-treated female rats are not indicative of hepatocarcinogenic potential for olestra in the rat. Dr. John Doull, a clinical toxicologist and temporary member of the FAC, agreed with the FDA evaluation that the basophilic liver foci findings are not significant and that basophilic liver foci are not predictors of carcinogenicity.\12\ Dr. Eugene McConnell,\13\ a presenter to the Olestra Working Group, agreed with Dr. Doull, and noted that the control groups in both chronic rat studies exhibited abnormally low incidences of foci compared to the foci rate historically observed in rats at these ages; he postulated that the addition of vitamins to the feed in both chronic rat studies may have caused this low foci occurrence rate in the control groups. The rate of foci in the treatment groups was compared to historical control rates and was slightly lower than historical controls. \12\Dr. John Doull, Kansas University Medical Center Transcript vol. 2, p. 113. \13\Dr. Eugene McConnell, D.V.M, D.V.B.T was chief of the Pathology Branch and Director of the Division of Toxicology Research and Testing for the NTP. Dr. McConnell is a diplomate of the American College of Veterinary Pathologists and the American Board of Toxicology. Dr. McConnell consulted for the petitioner and presented at its request. Transcript, vol. 2, p. 147. --------------------------------------------------------------------------- Dr. McConnell also noted that the slides were reviewed by (1) Board-certified pathologists in the contractor lab performing the study (2) board-certified pathologists employed by the petitioner, (3) an independent pathology laboratory,(4) a group of internationally known pathologists, and (5) FDA pathologists. All of the reviewers came to the same conclusion that none of the data suggests evidence of carcinogenic activity in either species. Therefore, in light of the discussion of the Olestra Working Group and the presentations of CSPI and Dr. McConnell, FDA confirms its conclusion that there was no olestra-related toxicity or carcinogenicity in these studies. c. Two-year chronic toxicity and carcinogenicity studies in mice. Two 2-year mouse studies were conducted to evaluate the chronic toxicity and carcinogenicity potential of olestra. The first mouse study compared three levels of olestra (2.5 percent, 5.0 percent, and 10.0 percent of the daily diet) to two control groups. Olestra was supplemented with vitamins A, D, E, and K to account for amounts which potentially would be lost due to the high levels of olestra fed. One of the two control groups provided basal levels of fat-soluble vitamins; the second control group was fed supplemental vitamins A, D, E, and K. To confirm the findings, a second mouse study was conducted with a chow-fed control group and a 10 percent olestra group supplemented with vitamins A, D, E, and K. One hundred mice of each sex were placed in a total of seven groups in the two studies. (The first mouse study had five groups and the second mouse study had two groups.) Fifty animals/sex/group were allocated to the carcinogenicity portions of each study, and all survivors sacrificed at 24 months. Fifteen animals/sex/group were allocated to the toxicity portion of each study, and all were sacrificed at 12 months. Finally, sentinel animals (35/sex/group) were included, and seven/sex/group were sacrificed at one, two, three, six, and nine months for assessment of hepatic vitamin A and E status. The studies included daily observations and weekly examinations. Body weights and food consumption were determined weekly. Ophthalmoscopic examinations were conducted pretest, and at scheduled sacrifice. Clinical chemistry and hematology data, gross necropsy observations, and organ weights were collected on animals sacrificed at 12 and 24 months in both studies. Complete gross postmortem examinations were performed on all animals. Selected organs were removed, weighed, and organ-to-body-weight and organ-to-brain-weight ratios were calculated for all mice surviving to scheduled necropsy. Histopathological evaluations were conducted on a full complement of tissues from all control and treated animals assigned to the carcinogenicity portion of both chronic studies. At the end of 24 months, there were no treatment-related effects in either study as determined by mortality, body weights, clinical pathology, gross necropsy findings, organ weights, hematology, clinical chemistries, or histopathology of a comprehensive collection of tissues. In the first study, there was an increase in the incidence of lung carcinomas and combined lung carcinomas and adenomas in mid-dose olestra-fed male mice but not in any other group. This association of olestra consumption with lung tumors in male mice in the first mouse study was not confirmed by the results of the second mouse study. Lung adenomas and carcinomas are common lesions in Swiss CD-1 mice and tend to have a high and variable background rate (Refs. 36 and 37). The increased combined incidence of lung adenomas or carcinomas in male mice in the first mouse study (Ref. 38) cannot credibly be associated with olestra consumption, and represents expected variation in spontaneous incidence of lung tumors in Swiss CD-1 mice (Ref. 37). Thus, upon review, FDA pathologists concluded that this was not an olestra-related effect because there was no other lung pathology, there was no relation between olestra exposure and time-to-onset of the tumors, the incidence of the tumors was typical for mice of this age and sex based on historical data, and there was no association between olestra exposure and lung tumors in other chronic rodent studies (Ref. 39). At the Olestra Working Group meeting, CSPI expressed concern about the increase in the incidence of combined lung carcinomas and adenomas in the mid-dose male mice.\14\ Dr. Doull noted that an analysis of the data for CSPI by Dr. Renata Kimbrough (Ref. 3) essentially agreed with FDA's conclusions. Specifically, although the mid-dose male mice in the first chronic study had an increased incidence in lung tumors, there was no dose response, the increased incidence of [[Page 3130]] lung tumors was not repeated in the second study, and the lung tumor incidence rate was within the range of that observed in the NTP program in lung tumors.\15\ Dr. Doull further stated his view that this data leads to the conclusion that olestra is not carcinogenic.\16\ \14\Transcript, vol. 2, p. 136. Discussion of this concern also appears in the White Paper (Ref. 3) \15\Transcript, vol. 2, p. 111. \16\Transcript, vol. 4, p. 113. --------------------------------------------------------------------------- Therefore, in light of the discussion before the Olestra Working Group, FDA confirms its conclusion that the lung tumors in this study were not an olestra-related effect. d. Dog feeding studies. The petitioner conducted two short-term feeding studies of olestra in beagle dogs. Olestra was fed at a level of 4 percent of the diet for 28 days or 15 percent of the diet for 30 days. Histological examination of several tissues, including the liver, revealed no abnormalities. The olestra-fed animals consumed more food because of the caloric dilution of the diet by olestra, but there was no difference in body weight gain. In a third study, olestra was fed to dogs at 10 percent of the diet for 91 days. No adverse effects were noted among the treated animals in terms of histopathology, hematology, or blood chemistries. The petitioner also conducted a 20 month chronic feeding study in five male and five female beagle dogs. The animals were fed a chow diet with 0 percent, 5 percent, or 10 percent olestra. Olestra diets were supplemented by adding 1.5 times the NRC recommended dietary level of vitamin A and 2.5 times the NRC recommended dietary level of vitamin E to the low-dose (5 percent) diet. The high-dose (10 percent) diet received 3.0 times the NRC recommended dietary level of vitamin A and 5.0 times the NRC recommended dietary level of vitamin E. The study included twice-daily observations, as well as weekly physical examinations, and determination of growth and food intake. Hematology, clinical chemistry, serum vitamin A and E concentrations, and ophthalmoscopic status were evaluated after 12 and 20 months of treatment. At the end of the study, all dogs were sacrificed and their tissues subjected to complete gross and microscopic examination. Organ weights and organ-to-body-weight ratios were determined for brain, adrenals, kidney, liver, ovary, testes, and thyroid/parathyroid. A complete set of tissues from all animals was examined by light microscopy. No evidence of toxicity was observed, and all animals survived the entire length of the study. Growth, as measured by body weight gain, was not affected by olestra ingestion. Food consumption was increased to offset the caloric dilution of the diet by olestra. No biologically significant changes were seen in any of the hematological or biochemical parameters measured. Histopathology revealed no olestra- related effects (Ref. 40). D. Toxicology Summary In summary, the results of the toxicological tests submitted by the petitioner support the conclusion that olestra is not toxic or carcinogenic, not genotoxic, and not teratogenic. Heating olestra, as would occur in the commercial preparation of savory snacks made using olestra, does not increase the absorption of the additive or affect its toxicity. IV. Effect of Olestra on Absorption of Drugs Because olestra is a fat-like material that has been shown to alter the absorption of some lipophilic nutrients, FDA considered whether the bioavailability of lipophilic drugs might also be affected by consumption of olestra. To address this question, the petitioner carried out a series of studies in both animals and humans. The petitioner established the following criteria to use in deciding which drugs to study: (1)-The drugs should have wide spread use by the general population. (2)-The absorption, metabolism and elimination of the drugs should be similar in rats and humans. (3)-The drugs should cover a wide range of solubilities, from water- soluble to fat-soluble. (4)-The drugs should include representatives of those used to prevent life-threatening situations. (5)-Most of the drugs should have partition coefficient data already available. (6)-The drugs must be commercially available in radiolabeled form. Using these criteria, the petitioner selected the following drugs for use in two rat studies: aspirin, diazepam, propranolol, and the oral contraceptives ethinyl estradiol and norethindrone. Because results of studies in rats are not definitive predictors of human conditions (Ref. 41), the petitioner also sponsored two human clinical trials to study the olestra/drug issue. In the first of these clinical trials, propranolol, diazepam, norethindrone, and ethinyl estradiol were included; in the second clinical study, the oral contraceptive Lo/ Ovral-28, containing norgestrel and ethinyl estradiol, was evaluated. A. Effect of Olestra on the Absorption of Selected Lipophilic Drugs (EC-40) The primary objective of this study was to determine whether olestra affects absorption of drugs relative to corn oil.This study was conducted in Sprague-Dawley derived male and female rats and had three separate experimental components. The olestra used was prepared from safflower oil, while corn oil served as the triglyceride control. Hydrogenated palm oil was added to both the olestra and control diets, to mimic the earlier proposed use of olestra in combination with convention oils. In the first experiment, 20 male rats were fed either a control diet with 6 percent added corn oil or a similar diet but with 6 percent added olestra for 13 days; the test animals were then fasted, weighed, subdivided into four groups (five rats per group), and gavaged with slurries of either the control or olestra diets to which tritiated diazepam or tritiated propranolol had been added. In the second and third experiments, no initial acclimation period was used. In the second experiment, 20 female rats were fasted, weighed, divided into four groups (five rats per group), and gavaged with slurries of either control or olestra diets to which tritiated ethinyl estradiol or tritiated norethindrone had been added. In the third experiment, 10 male rats were fasted, weighed, divided into 2 groups (5 rats per group), and gavaged with slurries of either control or olestra diets to which C14-labeled acetylsalicylic acid (aspirin) had been added. In all three experiments, serial blood and urine samples were taken over a 48-hour period after dosing. Fecal samples were also collected at 24-hour intervals. All samples collected were assayed for drug associated radioactivity, and the results evaluated for treatment related effects on drug absorption. The five drugs studied in these experiments cover a range of lipophilicity, from nonlipophilic (aspirin) to strongly lipophilic (ethinyl estradiol and norethindrone). The petitioner concluded that co-administration of the drugs with olestra did not affect the absorption of any of the drugs tested when compared with corn oil. FDA concludes that the petitioner's choice of drugs, which were selected based on physico-chemical properties, was reasonable. Further, the study correctly focused on rate and extent of absorption, both of which are important factors in the overall evaluation of human drug absorption. Although the use of total radioactivity measurements, [[Page 3131]] as was done in this study, is not a comprehensive evaluation taken alone, the study design is adequate as a first exploration of olestra/ drug interactions (Ref. 41). B. Effect of Olestra on the Absorption of Selected Lipophilic Drugs (EC-41) The objective of this study was to determine whether a single dose of olestra caused an alteration of the absorption or excretion profiles of lipophilic drugs that were orally administered prior to the olestra. This study was conducted with Sprague-Dawley derived male rats. After a 4 day acclimation period all rats were fasted, weighed, divided into treatment groups (four/group), and gavaged with either tritiated diazepam, tritiated propranolol, or C14-labeled aspirin (acetylsalicylic acid). Following each drug dosing, rats were gavaged with one ml of either water, corn oil, or olestra. Additional rats dosed with propranolol and aspirin received an olestra emulsion (one of the projected final forms for initial marketing of olestra). Serial blood and urine samples were collected over a 48-hour period, postdosing, while fecal samples were obtained at 24-hour intervals. Forty-eight hours after dosing all rats were sacrificed, their gastrointestinal tracts removed and the contents collected, selected organs excised, and carcasses frozen in liquid nitrogen and ground. All samples were assayed for drug-associated radioactivity. Results of the radioactivity assays were evaluated for treatment- related effects. The petitioner concluded that there were no differences in rate or extent of absorption of diazepam, propranolol, or acetylsalicylic acid when administered before olestra consumption compared with administration prior to water consumption. Drug excretion profiles were also not affected by olestra. Corn oil (a control substance) reduced the rate of absorption of all drugs studied. The petitioner concludes that these results demonstrate that olestra would not be expected to affect the acute absorption of drugs such as diazepam, propranolol or aspirin, and thus are consistent with EC-40. FDA concludes that, as with EC-40, the design and conduct of this investigation are adequate as a further exploratory study of the potential for olestra/drug interactions (Ref. 41). C. Effect of Olestra on Drug Bioavailability (EC-42) The objective of this clinical trial, consisting of 3 experiments, was to determine whether olestra consumption alters drug bioavailability in humans when used as a substitute for absorbable dietary fat. Subjects were assigned to test one drug in a crossover design so that bioavailability of the drug was evaluated with single doses of olestra, water, or a triglyceride (partially hydrogenated soybean oil) placebo treatment. Table 2 provides basic information on subject and treatment assignment. TABLE 2.--SUBJECT AND TREATMENT ASSIGNMENT IN EC-42 ---------------------------------------------------------------------------------------------------------------- Drug and treatment Exp. No. Subject No. male/female Age Range (years) amount ---------------------------------------------------------------------------------------------------------------- 1.................................... 5/3.................... 27 to 47............... Propranolol, 20 mg 2.................................... 4/4.................... 20 to 40............... Diazepam, 5 mg 3.................................... 0/10................... not available.......... Norethindrone, 1 mg and Ethinyl estradiol, 0.07 mg ---------------------------------------------------------------------------------------------------------------- In each experiment, 18 g of olestra, 18 g of triglyceride, or six ounces of water were consumed following ingestion of the respective drug under study. Serial blood samples collected from all subjects were processed and the resulting serums frozen for subsequent drug analyses. The data on peak serum concentrations, times to peak, and areas under the concentration curves (AUC) were analyzed statistically for treatment effects. Based on its analyses of the results from the three experiments, the petitioner concluded that there were no statistically significant differences in the absorption of the drugs administered with olestra, triglyceride placebo, or water as assessed by total area under the curve (AUC) and time to peak concentration data. The time to peak concentration values for diazepam were slightly longer with the triglyceride placebo than with olestra. There was wide, although not unexpected, between-patient variability. The petitioner concluded that a single dose of 18 g of olestra did not alter the bioavailabilitypara.characteristics of orally administered propranolol, diazepam, or norethindrone/ethinyl estradiol when compared to water or a triglyceride such as partially hydrogenated soybean oil. FDA concludes that the design of this clinical study was excellent, and that the study may be used by itself, without any reliance on the two studies in rats, to assess olestra's potential for affecting absorption of lipophilic drugs. The results from EC-42 demonstrate that olestra does not interfere with the absorption of drugs when administered at the 18 g dose (Ref. 41). D. Effect of Olestra on the Systemic Levels of Steroidal Hormones in Women Taking Oral Contraceptives (EC-51) The objective of this clinical trial was to determine the effect, if any, of chronic olestra consumption (targeted at 20 g/d) on the absorption and efficacy of a low-dose oral contraceptive in normal women. Thirty healthy, menstruating female subjects aged 20 to 38 years were assigned to two groups. A double-blind, placebo-controlled, crossover study design was used which covered two complete ovarian cycles. Subjects were instructed to begin taking the oral contraceptive Lo/Ovral-28 (0.30 mg norgestrel and 0.03 mg ethinyl estradiol), 5 days before the onset of menstruation. One group of subjects received food items with triglyceride placebo, while the other group received similar food items containing a ``mid-range'' olestra formulation. Daily intake of olestra was set at 18 g with one-third (6 g) of the daily dose being consumed at each meal. At the conclusion of the first 28-day cycle, the treatments were crossed over (placebo to olestra, olestra to placebo). All subjects were asked to take their oral contraceptive only in the morning and before the morning meal. Serum progesterone levels were determined at a baseline visit, 5 to 7 days after menstruation and twice weekly for the remainder of the ovarian cycles. Serial blood samples were collected during each of the two ovarian cycles. These samples were then processed and the serums frozen for subsequent drug analysis. Results were evaluated for treatment effects by comparing AUC, maximum drug concentration, and time to maximum concentration data. The petitioner concluded that there were no significant effects of consuming 18 g of olestra on the absorption of either norgestrel or ethinyl estradiol, the [[Page 3132]] two steroid components of Lo/Ovral-28. Serum progesterone levels in subjects in both the olestra and triglyceride placebo groups were found to remain in a range that would prevent ovulation, thereby providing evidence that oral contraceptive efficacy was not affected by olestra. The petitioner also stated that because the oral contraceptive used in this study contains the lowest amounts of two of the most lipophilic steroid hormones (norgestrel and ethinyl estradiol), the results from this study should prove valid for ``all high-dose oral contraceptives having less lipophilic constituents.'' In addition, the petitioner believes that the data from EC-51 provide further support generally for the conclusion from other studies in animals and humans that olestra consumption does not alter the absorption of lipophilic drugs, and therefore, will not affect the efficacy of orally administered drugs. FDA believes that this study is an excellent extension from single- dose olestra to chronic dosing, at least for the once-a-day situation. Further, in this study, there was no evidence that olestra would affect the efficacy of orally administered drugs (Ref. 41). E. Summary The petitioner has submitted two animal studies and two clinical studies assessing olestra's potential to alter drug absorption. Procter & Gamble believes that these studies demonstrate that olestra does not alter the absorption nor affect the efficacy of orally administered drugs. Members of the Olestra Working Group were unanimous that, with respect to drugs, all the issues had been identified and there were sufficient data to address each issue.\17\ There was also nearly unanimous agreement that, with respect to drug interactions, there was no obstacle to approval and reasonable certainty of no harm from olestra consumption.\18\ \17\Transcript, vol. 4, p. 50. \18\Transcript, vol. 4, p. 50. --------------------------------------------------------------------------- During the Olestra Working Group and FAC meetings and in numerous comments to FDA, individuals have expressed concern about the effects of olestra on coumarin drugs (e.g., Coumadin or warfarin, Dicumarol, etc.) as well as other drugs. Dr. Ian Greaves, a specialist in environmental and occupational medicine,\19\ expressed concern about persons taking anticoagulants such as coumarin drugs that antagonize Vitamin K. He asked how olestra would bind to coumarin and whether there would be difficulty in maintaining an anticoagulant status in people receiving coumarin who intermittently eat olestra-containing products. He stated that his experience with managing patients on anticoagulants is that some of them are very variable for no good reason, and he could easily foresee a patient becoming either overly anticoagulated or under-anticoagulated, depending on whether Vitamin K was being bound or whether the coumarin was being bound. Also, if a person taking coumarin happened to have an intra-cerebral bleed or bleed from his gastrointestinal tract and was also consuming olestra, he felt it would be difficult to know whether olestra had a role in the bleeding. Finally, he stated he was concerned about other fat-soluble drugs, particularly those that cross the blood-brain barrier such as anticonvulsants, psychotropic drugs, and antidepressants. Dr. Greaves's questions covered the concerns that were raised by other individuals. \19\Dr. Ian Greaves is an Associate Professor and Deputy Director, Minnesota Center for Environmental and Health Policy, University of Minnesota School of Public Health. Dr. Greaves presented at the request of CSPI. Transcript, vol. 2, p. 265. --------------------------------------------------------------------------- FDA notes that the results concerning the hormonal preparations are extremely useful because these drugs represent extremely lipophilic substances and are substances that have a narrow therapeutic index in which a lowering of the absorbed concentration would be a concern. In addition, the drug, propranolol, is a compound that has very similar physical/chemical properties to Coumadin or sodium warfarin,\20\ a drug about which FDA has received comments concerning olestra's effects. In response to a question by an FAC member, FDA noted that in the previous 5 years, there has been only one drug that FDA has reviewed that is more lipophilic than the hormone drugs tested in the human drug- interaction studies. That drug is a very specialized drug (Atovaquone), which is an anti-pneumocystis drug used in AIDS patients.\21\ Therefore, FDA expects that the results observed in the reviewed studies would be representative of nearly any drug on the market. \20\Transcript, vol. p. 124. \21\Transcript, vol. p. 124. --------------------------------------------------------------------------- Regarding coumarin drugs specifically, FDA notes that the effects of a variety of meals (e.g., high-protein, high-carbohydrate, and high- fat) on absorption of sodium warfarin (Coumadin), the most commonly prescribed form of coumarin, were studied and no effect was seen in the total amount of sodium warfarin absorbed. Also, there was no effect on absorption when Coumadin was consumed with high-fat or high-protein meals. When consumed with a high-carbohydrate meal, Coumadin was more slowly absorbed, but only for the first hour after ingestion of the drug\22\ (Ref. 42). Therefore, FDA would not expect significant effects on Coumadin absorption from olestra consumption. \22\Transcript, vol. p. 119. --------------------------------------------------------------------------- Olestra's effects on vitamin K are discussed in the Nutritional Studies section below. FDA concludes that the test compounds studied adequately represent the range of physical properties of drugs marketed for human use, and that the magnitude of olestra's effects on drug absorption were minimal, when compared to the effects normally encountered in drug-food interaction studies. FDA further concludes, considering the results of all four studies, the discussions during the Olestra Working Group and FAC meetings, comments received, and information in the literature, that there is no evidence that consumption of olestra would significantly influence the rate or extent of absorption of drugs (including Coumadin drugs). V. Nutritional Studies A. Issues Associated with Olestra The petitioner has hypothesized that olestra interferes with the absorption of fat-soluble nutrients when the nutrients partition into olestra in the GI tract. When this happens, the portion of the nutrients that is present in the olestra phase is unavailable to the micelle-mediated transport system and, rather than being absorbed by the body, is excreted in the feces along with the olestra. Neither existing olestra data nor the partitioning mechanism suggest that water-soluble nutrients would be affected by olestra. However, certain water-soluble nutrients such as folate and vitamin B12 (hard-to-absorb nutrients) are absorbed in multi-step processes. The multi-step nature of the processes might allow the opportunity for olestra to interfere with key steps in the processes, such as binding or cleavage reactions. Calcium, zinc, and iron are limited in the U.S. diet; thus, any effect on their absorption might increase the risk of nutritional inadequacy. In addition, the nutrients would be present in the diet at levels that are small, on a mass basis, relative to the amount of olestra. Thus, if olestra has an effect on water-soluble nutrients, these five nutrients (folate, vitamin B12, calcium, zinc, and iron) would be the most important water-soluble nutrients [[Page 3133]] to monitor and the most likely to reflect adverse nutritional effects. Therefore, folate, vitamin B12, calcium, zinc, and iron were chosen as representative markers for olestra's effects on the nutritional status of water-soluble nutrients. The potential nutritional effects of olestra consumption were studied in both humans and animals. The pig was chosen as the appropriate animal model because it has a gastrointestinal tract similar to that of man; it is able to ingest, tolerate, and metabolize fat at a level comparable to that found in the human diet; and its vitamin stores and nutritional indices are responsive to dietary changes. Where possible, FDA has relied upon the results of human consumption studies as the primary determinants of olestra's safety, thereby avoiding the uncertainties raised by extrapolating from the pig to humans. Thus, FDA is relying primarily on the human studies to assess olestra's effects on vitamins E, D, K, and B12, and on folate and iron. There are certain nutrients, such as vitamin A, for which no noninvasive procedure can be used to assess status in humans. Therefore, FDA has relied upon the results of the pig studies for determining olestra's effects on vitamin A. In addition, there are certain advantages to studying olestra's nutritional status in pigs. The studies can be conducted over the major developmental and growth periods of the pig's life, dose levels higher than those in man can be studied, and invasive techniques can be used to measure nutrient stores in tissues (such as bone and liver). Therefore, results from the pig studies are valuable supportive information that expand upon the knowledge gained in the human studies. To apply the results of the pig studies to humans, it is necessary to correlate the percent olestra fed in the pig diet to g/p/d olestra. Olestra's effects on nutrients are caused by its physical presence in the gut. If nutrients dissolve into olestra, they will be carried out of the body with the olestra rather than being absorbed. The amount of olestra's effect depends on the amount of olestra present in the GI tract compared to other fats (as well as on the solubility of the vitamins in olestra). Thus, FDA has concluded that the most appropriate means for correlating olestra's effects in animals to humans is the percentage by weight of olestra in the diet. For a person eating about 2,000 calories/d, 10 g of olestra would be about 2.4 percent of the diet (Ref. 43). B. Effects of Olestra on Fat-Soluble Vitamins- The effect of olestra on fat-soluble vitamins was assessed in five nutritional studies with humans and five studies with pigs, as summarized in Table 3. TABLE 3.--SUMMARY OF STUDIES DESIGNED TO ASSESS NUTRITIONAL EFFECTS OF OLESTRA CONSUMPTION ---------------------------------------------------------------------------------------------------------------- Human Studies Pig Studies ---------------------------------------------------------------------------------------------------------------- 8-week clinical dose response (8-week DR) 26-week dose response and vitamin restoration (26-week DR/VR) 8-week clinical vitamin restoration (8-week VR) 39-week vitamin restoration (39-week VR) 6-week vitamin D/K status in free-living subjects (6- 12-week dose response (12-week DR) week vitamin D/K) 16-week vitamin E status in free-living subjects (16- 12-week vitamin restoration (12-week VR) week vitamin E) 14-day vitamin A/fat absorption (14-day vitamin A/fat) 4-week dietary context (4-week DC) ---------------------------------------------------------------------------------------------------------------- In evaluating olestra's nutritional effects, FDA believes that it is appropriate to rely primarily on the two 8-week clinical studies because in these studies, there was complete control of nutrient intake, they were well designed, and most nutritional parameters were monitored. Also, these two studies were performed recently using state- of-the-art analytical techniques and were designed taking into consideration findings from previous studies. FDA believes that the 16-week vitamin E study, the 6-week vitamin D/K study, and the 14-day vitamin A/fat study are appropriately used to support the findings in the two 8-week studies. The results of these latter three studies do not weigh as heavily in the safety evaluation because of their limitations: the 16-week vitamin E and 6-week vitamin D/K studies were conducted in free-living subjects so that it was not possible to control completely or have more than imprecise knowledge of nutrient intake; the vitamin A/fat study investigated only olestra's effects on preformed vitamin A absorption and provides less information than the pig studies for assessing olestra's long-term effects on vitamin A stores (which are derived from both preformed vitamin A and carotenoids). Of the studies performed in the pig, FDA believes that it is appropriate to rely primarily on the results of the 26-week DR/VR and 39-week VR studies to assess olestra's nutritional effects because these studies were the longest term and were designed to confirm the results of the 12-week DR and 12-week VR studies. The 4-week DC study was more limited in scope and duration, and was intended to demonstrate how olestra's effects are modified by changes in dietary patterns. 1. Primary Human Studies- The petitioner performed two 8-week human studies, in both of which the entire diet of the subjects was controlled during the study. The first study was the 8-week DR study which was intended to determine the dose-response effect of olestra on the status of folate, zinc, iron, and vitamins A, E, D, K; on the absorption of vitamin B12; and on the bioavailability of -carotene and total carotenoids. The 8- week VR study was intended to determine the efficacy and safety of compensation with vitamins A, E, and D, and to confirm the conclusions drawn in the 8-week DR study about the effects of olestra on vitamin K, zinc, and iron status, serum 25-hydroxyvitamin D2 (25-OHD2) concentration, carotenoid bioavailability, and vitamin B12 absorption. These two studies are of similar design and the results are complementary. a. Eight-week DR study design. The 8-week DR study was a parallel, double-blind, placebo-controlled study with controlled diets fed for 8 weeks. Subjects were normal, healthy, 18 to 44 year-old males and females. The study had four groups of 21 to 24 subjects per group (88 subjects total). Subjects were randomly assigned to treatment groups that were balanced with respect to age, sex, body mass index (BMI), serum -tocopherol, and total serum carotenoid concentrations. Subjects were provided with all meals for 56 days.- The diets were formulated to provide about 15 percent of calories from protein, about 55 percent of calories from carbohydrate, and about 30 percent of calories from fat. The total digestible fat content was kept the same across the four treatment groups by adding [[Page 3134]] triglyceride, in the form of butter, margarine, or vegetable oil, into the diets to compensate for the amount of fat replaced by olestra in the olestra-containing foods. Therefore, the total amount of lipid (digestible fat plus olestra) increased with increasing olestra dose. Olestra was added to food items (potato chips, muffins, biscuits, and cookies) by substituting olestra for triglyceride in recipes or in cooking oils. Because each meal contained olestra, or the corresponding placebo (triglyceride), this study design provided maximum opportunity for olestra to interfere with nutrient absorption. The diets provided each subject with 80 percent to 120 percent of the RDA of folate, zinc, and vitamins A, D, E, and K. Calcium and iron intakes were not targeted to be within the 80 percent -120 percent RDA range, although they were controlled and kept consistent among the diets. Vitamin B12 levels were allowed to exceed the 80 to 120 percent RDA range in order to maintain zinc and protein consumption at the target levels. In addition to the vitamin D in the diet, subjects were given 20 g/day (two RDA) of vitamin D2 as a supplement, one third of which was consumed with each meal.- The dosages of olestra were 0 (placebo), 8, 20, and 32 g/d. Body weights were measured every week and the subjects were questioned daily about changes in their health, including GI symptoms. If a GI symptom was experienced, the subject completed a detailed questionnaire that asked about the type, severity, and duration of symptoms they experienced. (The monitoring and reporting methods for adverse experiences is discussed in section VI.B. of this document.) Table 4 summarizes the measurements that were made to assess the status of the various nutrients. Most parameters were measured at baseline (week 0) and at 2-week intervals throughout the 56-day study period. TABLE 4.--MEASUREMENTS OF MICRONUTRIENT STATUS IN THE EIGHT WEEK DR STUDY ---------------------------------------------------------------------------------------------------------------- Nutrient Measurements ---------------------------------------------------------------------------------------------------------------- Vitamin A Serum retinol concentration\23\, serum carotenoid concentration Vitamin E Serum -tocopherol concentration Vitamin D Serum concentration of 25-OHD2, 25-hydroxyvitamin D3 (25-OHD3), and 1,25-dihydroxyvitamin D (1,25-(OH)2D) Vitamin K Serum phylloquinone concentration, urinary excretion of -carboxy glutamic acid, plasma concentration of des-carboxy prothrombin (PIVKA-II), plasma prothrombin concentration, and prothrombin time, and partial thromboplastin time Folate Serum and red blood cell folate concentration Vitamin B12 Schilling test, serum vitamin B12, serum vitamin B12 metabolites Zinc Serum and urinary zinc concentrations ---------------------------------------------------------------------------------------------------------------- \23\Serum retinol concentration is the only practical measure of preformed vitamin A status that can be made in humans who have adequate liver stores. (Other measures require invasive tissue sampling, such as measurements of liver stores.) b. Eight-week VR study design. The study design for the 8-week VR study was the same as that of the 8-week DR study, except for the following elements. The 8-week VR study had 6 groups, each containing 16 or 17 subjects (100 subjects total). The measurements of micronutrient status in the 8-week VR study differed from those in Table 4 in that folate and zinc were not monitored while iron status was monitored by measuring serum ferritin and iron concentrations and total iron binding capacity. Unlike the 8-week DR study, no vitamin D2 supplement was consumed by the test subjects. Finally, in addition to the vitamins provided in the diet, graded levels of vitamins A, E, and D were provided, as described in Table 5. TABLE 5.--VITAMIN DOSES EXPRESSED AS PER GRAM OF OLESTRA (/G) AND -PER DAY (/D) FOR THE SIX TREATMENT GROUPS IN 8-WEEK VR STUDY ---------------------------------------------------------------------------------------------------------------- Vitamin A Vitamin E Vitamin D2 ----------------------------------------------------------------------------- Treatment Group Olestra (g/d) g/ g/ g/ g/ g d mg/g mg/d g d ---------------------------------------------------------------------------------------------------------------- 0 (placebo)....................... 0 0 0 0 0 0 8................................. 83 664 2.5 20 0 0 20................................ 33 660 1.5 30 0.20 4 20................................ 83 1660 2.5 50 0 0 20................................ 132 2640 3.5 70 0.80 16 32................................ 83 2656 2.5 80 0 0 ---------------------------------------------------------------------------------------------------------------- c. Results and conclusions from primary human studies.--i. Vitamin A. In the human diet, there are two sources of dietary vitamin A, preformed vitamin A (retinyl esters) and carotenoids such as - carotene that are converted in the body into vitamin A (provitamin A carotenoids). Partitioning of either of these sources of vitamin A into olestra could affect vitamin A levels in the body. The petitioner concluded that there was no effect of olestra in either of the two 8-week studies on the serum concentration of retinol. This result was not unexpected because serum retinol concentrations are relatively stable and not subject to significant change except under conditions of prolonged and inadequate vitamin A intake. Only under such extreme conditions would changes in liver vitamin A storage be reflected by changes in serum retinol. Thus, the petitioner concluded, and FDA agrees, that to establish the effect of olestra on vitamin A status in humans, data on vitamin A liver stores collected in the pig studies and data on the postprandial absorption of vitamin [[Page 3135]] A in man must be considered. Those data are discussed in sections V.B.3.c.i. and V.B.2.c. of this document. ii. Vitamin E. The petitioner evaluated the effect of olestra on vitamin E status and found that there was a highly significant trend in decreased serum levels of vitamin E with increasing olestra dose in the 8-week DR study, an effect evident by day 14 of the study. Serum vitamin E was reduced by 6 percent, 17 percent, and 20 percent compared to control levels when olestra was consumed at 8, 20, and 32 g/d respectively in every meal. The maximum effect was obtained between 2 and 4 weeks. The petitioner calculated, based on the results of the 8-week VR study, that the effects on tissue concentrations of vitamin E were offset by the addition of 2.07 mg of vitamin E (d--tocopheryl acetate) per g olestra. This level is equivalent to 1.9 mg - tocopherol equivalents/g olestra and 0.94 RDA of vitamin E per 1 oz serving of savory snacks containing 10 g of olestra. FDA agrees that 1.9 mg of -tocopherol equivalents/g olestra adequately restored serum vitamin E levels in this study, as indicated in the data adjusted for baseline serum vitamin E levels\24\ (Ref. 44). FDA finds that this study adequately controlled vitamin E consumption, analyzed appropriately for vitamin E levels, and was of sufficient duration to observe olestra's effect, because the effect had reached a plateau after a few weeks into the study (Ref. 43). Therefore, FDA agrees that compensation for olestra's effects on vitamin E can be calculated from the results of this study, and further agrees that 1.9 mg of -tocopherol equivalents per g of olestra is the appropriate compensation level. \24\In controlled diet studies such as this, the controlled diet is often better in many respects than the free-living diet of the subjects, thus it is not unusual that the basline vitamin E levels were lower than controlled-diet levels. Therefore, adjustment for baseline levels is appropriate. --------------------------------------------------------------------------- iii. Vitamin D. In the human diet, there are two sources of vitamin D, dietary (vitamin D2) and endogenous (vitamin D3) produced in the body via sunlight-catalyzed dermal synthesis. The nature of the dose-response effect of olestra on dietary vitamin D2 was determined by measuring serum levels of 25-OHD2, which is derived only from dietary vitamin D. Serum levels of 25-OHD3 (from dermally synthesized vitamin D3), 1,25-(OH)2D, and 25-OHD were also measured to assess olestra's effects on total vitamin D status. The serum concentration of 25-OHD reflects total vitamin D status. The petitioner found that there was an olestra treatment effect in the 8-week DR study on the serum concentration of 25-OHD2. At the end of the study, the reductions in 25-OHD2 were 23 percent, 13 percent, and 27 percent for 8, 20, and 32 g olestra/d, respectively, relative to control. The effect had levelled off within 4 weeks. There was no effect on serum 25-OHD3 or 1,25-(OH)D. In this study, the diet contributed 55 to 68 percent to total vitamin D status (the remainder coming from sunlight). The amount supplied by the diet was relatively high because of excess vitamin D2 supplied by the dietary supplement. Although the subjects in the 8-week VR study did not receive supplements (the diet contributed 12 to 20 percent of total vitamin D), the reductions in 25-OHD2 in the 8-week VR study were similar to those observed in the 8-week DR study: 22 percent, 29 percent, and 22 percent for 8, 20, and 32 g olestra/day, respectively, relative to control. The reductions in serum total 25-OHD were less compared to the reductions in the 8-week DR study because a larger fraction of the total vitamin D was endogenous. The petitioner concluded that olestra's effect on serum vitamin D2 in the 8-week VR study could be offset by adding 0.07 times the RDA of vitamin D2 per 1 oz serving of savory snack containing 10 g olestra (equivalent to .07 g/g olestra or 2.7 IU). The petitioner further concluded that olestra's effect on vitamin D status is not nutritionally significant because the effect is relatively small (on the order of a few percent in the 18- week VR study) and sunlight synthesis is a more important contributor to total vitamin D levels. FDA agrees with the petitioner that olestra reduced serum vitamin D in both studies. Because the effect of olestra on serum vitamin D2 levels had levelled off within the first 4 weeks of the study, FDA considers the studies of sufficient length to assess olestra's effects (Ref. 43). However, it is difficult to quantify olestra's effect because of confounding factors, such as the lack of a strong relationship between dose and reductions in 25-OHD2 in both studies. In addition, the effect of olestra on serum total 25-OHD levels is difficult to quantify in the 8-week VR study because total serum 25-OHD levels were falling in the control group as well as the treated group during the study. (For example, total serum 25-OHD levels in the group not consuming olestra decreased 30 percent over the course of the study.) Compensation of two of the 20 g/d olestra groups with 0.2 and 0.8 g vitamin D2/g olestra reduced the decrease in total serum 25-OHD (which was due to both olestra and test diet effects). At the 0.2 g/g olestra supplementation level, the decrease in total 25-OHD was slightly less than in the group not consuming olestra (26.8 percent vs. 30 percent respectively). With the higher level of compensation (0.8 g/g olestra) the decrease in 25-OHD was about one-half that of the group not consuming olestra (15.6 vs. 30) (Ref. 45). Although FDA believes that the variability of the data and the ``on diet'' effects on vitamin D status make quantitation of the magnitude of olestra's effects difficult, the agency concludes that the 8-week VR study can be used to estimate olestra's effects on vitamin D because dietary vitamin D2 consumption was not excessive and [Text truncated at 120,000 characters. The full text is on the page linked above.] --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A96-1584. Public record. Not legal advice.