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Background: The 1996 Food and Drug Administration approval of the fat substitute olestra (sucrose polyester) called for active postmarketing surveillance because preapproval studies showed that olestra may lower circulating concentrations of fat-soluble nutrients such as vitamins and carotenoids., Objective: The objective of the Olestra Post-Marketing Surveillance Study was to examine whether customary consumption of olestra-containing savory snacks was associated with changes in serum fat-soluble vitamin and carotenoid concentrations among free-living persons in geographically and ethnically distinct US cities., Design: Adults (n = 2535) and their children aged 12-17 y (n = 272) in Baltimore, Minneapolis, and San Diego attended clinic visits during which data were collected on diet, savory snack consumption, lifestyle, and anthropometric indexes. Blood samples were drawn to assay carotenoids and vitamins A, D, E, and K. Data and blood samples were collected both before and after the nationwide introduction of olestra. General estimating equations were used in multivariate-adjusted models that examined olestra's association with the specified serum nutrients., Results: Compared with no intake, the top 2 tertiles of olestra use in adults were associated with circulating carotenoid concentrations that were modestly but significantly lower (4.3% to 22.4%). There were no significant associations of olestra with any serum nutrients among adolescents., Conclusions: This active postmarketing surveillance study of a food additive suggests that small decreases in serum fat-soluble nutrients are attributable to olestra use. Although health outcomes were not measured here, it is unlikely that these small changes in nutrient measures would adversely affect health.

The objective of this study was to determine whether vitamin supplementation during long-term (36 wk) ingestion of olestra supplemented with vitamin E could prevent decreases in vitamin E, vitamin A, and carotenoids. This was a 36-wk study of 37 healthy males randomly assigned to consume a control diet composed of 33% energy from fat, a similar diet in which one third of the energy from fat had been replaced with olestra, or a fat-reduced (25% of energy from fat) diet. Subjects also ingested a daily multivitamin (Centrum). Serum concentrations of alpha-tocopherol, retinol, beta-carotene, lycopene, and lutein + zeaxanthin were analyzed by HPLC. Subjects eating the olestra-containing diet had substantial decreases in serum beta-carotene, lycopene, and lutein + zeaxanthin, which occurred by 12 wk; these changes were found despite correcting for serum total cholesterol or BMI. Serum beta-carotene and lycopene concentrations were below the lower limit of the reference range (<0.186 and <0.298 mumol/L, respectively) at one or more time points. The slight decline in serum alpha-tocopherol concentration, significant at 24 wk, was caused by the decline in serum cholesterol. Retinol concentrations decreased with time in all 3 groups, but were not affected by olestra. We conclude that supplementation with a multivitamin containing vitamins A and E was adequate to prevent olestra-induced decrease in serum alpha-tocopherol and retinol. Olestra-induced decreases in serum beta-carotene, lycopene, and lutein + zeaxanthin were not prevented by the vitamin supplement used in this study.

Objectives: This study examined the association between authors' published positions on the safety and efficacy in assisting with weight loss of the Procter & Gamble (P&G) fat substitute olestra and their financial relationships with the food and beverage industry., Methods: Journal articles about olestra, and their authors, were classified as supportive, critical, or neutral with respect to its use. Authors not known to have industry affiliations were surveyed about their financial relationships., Results: Supportive authors were significantly more likely than critical or neutral authors to have financial relationships with P&G (80% vs 11% and 21%, respectively; P <.0001). All authors disclosing an affiliation with P&G were supportive., Conclusions: Because authors' published opinions were associated with their financial relationships, obtaining noncommercial funding may be more essential to maintaining objectivity than disclosing personal financial interests.

Objective: To report a case of significant additive gastrointestinal effects with concomitant use of orlistat and an olestra-containing snack food., Case Summary: A 16-year-old African American girl with type 2 diabetes, hypercholesterolemia, and hypertension was participating in a pilot study that tested the safety and efficacy of orlistat. After 2 weeks of orlistat treatment, the patient presented to the clinic with complaints of soft, fatty/oily stools, flatus with discharge, abdominal pain, increased flatus, and fecal incontinence. On further questioning, it was determined that she was also consuming approximately 5 ounces of olestra-containing potato chips on a daily basis. The patient eliminated olestra from her diet and returned to the clinic with substantially diminished gastrointestinal adverse effects, despite continuing to take orlistat., Discussion: This is the first published case describing additive gastrointestinal effects after concurrent use of orlistat and olestra. Education about the potential for serious additive gastrointestinal adverse effects is important to prevent premature and unnecessary discontinuation of orlistat therapy. Awareness of this potential interaction could be especially important for patients with underlying disease states in which severe gastrointestinal symptoms could result in significant complications., Conclusions: This case illustrates that significant gastrointestinal distress may result after olestra consumption during orlistat therapy. All patients receiving orlistat for the management of obesity should be properly educated about this potential drug-food interaction.

Following approval of the fat replacer olestra for use in preparing savory snacks, Procter & Gamble implemented a postmarketing surveillance program to monitor marketplace introduction. Three and one-half percent of all health effects reported by consumers to the surveillance toll-free number were allergy-type symptoms (e.g., rash, itching, edema, hives, dyspnea). Because of these reports, we investigated whether olestra or some component of olestra snacks was a likely allergen in some subset of the population. A single center, randomized, double-blind, placebo-controlled, within-subject crossover food challenge study was conducted to confirm or refute the allergenicity of olestra snacks. Of the 65 subjects who reported symptoms consistent with immediate hypersensitivity to olestra's postmarketing surveillance program, 14 men and women traveled to the Arkansas Children's Hospital Research Institute to participate in this study. Each subject underwent a standard skin prick test at the beginning of the study, to help determine what component, if any, of the olestra product was allergenic. Following the skin prick test, subjects ate in random order, olestra-containing potato chips and regular fat-containing potato chips. The dose of potato chips consumed at each challenge was at least the amount alleged to have caused the symptoms that prompted the consumer to phone the postmarketing surveillance toll-free number. No subject experienced an allergic reaction after consuming the olestra-containing chips. Nor did any subject elicit a positive response to olestra following the skin prick testing. Two subjects had positive reactions consistent with immediate hypersensitivity after consuming the regular-fat, placebo potato chips. The results of this study confirm that olestra is unlikely to have an allergenic potential., (Copyright 2001 Academic Press.)

Following U.S. Food and Drug Administration (FDA) approval for the use of olestra, a noncaloric fat substitute (brand name Olean) in food snacks, the manufacturer agreed to provide safety updates on market experience to the FDA. However, guidelines for food product postmarketing surveillance (PMS) are not available and those typically used with medical products were only partly applicable. In modeling the Olean program, we drew from experience with consumer products and incorporated elements typical of medical product PMS. A cooperative effort was established with Olean snack manufacturers and a two-tiered, multidisciplinary approach enlisting Consumer Relations and Medical Affairs personnel was used to maximize use of specialized skills. The result of this effort was implementation of a reliable PMS system which could handle a high volume of reports from consumers while providing pertinent data required for medical interpretation of these reports. Summaries of data for the Olean snack manufacturers and FDA were generated in timely fashion. In addition to collection of the spontaneous reports from consumers, a clinical studies program was undertaken and an independent medical advisory panel was established. Through these, we gained perspective on the spontaneous reports and additional confirmation of the safety of olestra in savory snacks., (Copyright 2001 Academic Press.)

Market introduction of savory snacks containing olestra offered an opportunity to evaluate the safety of olestra in a free-living population and thereby compare the outcome to the previously established safety profile determined in clinical trials in which subjects were required to eat predetermined amounts at prescribed intervals. Therefore, a multifaceted postmarketing surveillance program was designed to evaluate consumer experience and safety of olestra in the marketplace. Customer comments were solicited through toll-free telephone numbers. Collected data were evaluated by both internal and external medical experts. About 10% of toll-free telephone calls reported health effects, most of which were gastrointestinal (GI) in nature. Clinical studies were designed and conducted to determine potential GI effects under the range of consumption patterns reported by toll-free calls. Health effects reported were those found commonly in the general population and analyses of the data found no biological reason to conclude that serious or meaningful health effects were the result of olestra consumption., (Copyright 2001 Academic Press.)

The aim of this study was to determine the effects of olestra and sorbitol consumption on three accepted objective measures of diarrhea (stool output >250 g/day, liquid/watery stools, bowel movement frequency >3/day), and how stool composition influences reports of common gastrointestinal symptoms. A double-blind, placebo-controlled study compared the effects of sorbitol (40 g/day in candy), a poorly absorbed sugar-alcohol with known osmotic effects, with those of olestra (20 or 40 g/day in potato chips), a nonabsorbed fat, on objective measures of stool composition and GI symptoms. Sixty-six subjects resided on a metabolic ward for 12 days: 2 days lead-in, 4 days baseline, 6 days treatment. Sorbitol 40 g/day resulted in loose/liquid stools within 1-3 h of consumption. In contrast, olestra resulted in a dose-responsive stool softening effect after 2-4 days of consumption. Subjects reported "diarrhea" when mean stool apparent viscosity (peak force (PF), g) decreased from a perceived "normal" (mean +/- SE, 1355 +/- 224 g PF; firm stool) to loose (260 +/- 68 g PF) stool. Mean apparent viscosity of stool during treatment: placebo, 1363 +/- 280 g (firm); olestra 20 g/day 743 +/- 65 g (soft); olestra 40 g/day, 563 +/- 105 g (soft); and sorbitol 40 g/day, 249 +/- 53 g (loose). Of the 1098 stool samples collected, 38% (419/1098) were rated by subjects as "diarrhea," yet only 2% of treatment days (all in the sorbitol treatment group) met commonly accepted criteria for a clinical diarrhea. Sorbitol, but not olestra, increased the severity of abdominal cramping, urgency and nausea compared to placebo. Olestra consumption, at levels far in excess of normal snacking conditions, resulted in a gradual stool softening effect after several days of consumption, did not meet any of the three objective measures of diarrhea, and did not increase GI symptoms. Sorbitol consumption, at only 80% of the dose requiring a "laxative effect" information label, resulted in rapid onset loose/liquid stools and a significant increase in abdominal cramping, urgency and nausea. Overall, subjects categorized stool as "diarrhea" when stool decreased from their perceived "normal," but the vast majority of these reports were not associated with clinically significant diarrhea., (Copyright 2000 Academic Press.)

We conducted a prospective, randomized, double-blind, placebo-controlled, parallel-group trial to evaluate the effect of the moderate consumption of snacks containing olestra on the international normalized ratio (INR) in 40 patients receiving long-term warfarin therapy. Patients continued their warfarin regimen and were assigned to receive 1.5 servings/day (42 g) for 2 weeks of Pringles Original Flavor Fat Free Potato Crisps with Olean (12 g olestra/1.5 servings) or Pringles Original Flavor Potato Crisps (placebo group). Patients' INRs were measured weekly for 2 weeks. Thirty-six patients completed the first week of the trial. After 1 week, the mean change in the INR from baseline increased by 0.02 +/- 0.5 in the olestra group and by 0.17 +/-0.4 in the placebo group (p= 0.327). Ten patients in the olestra group and 12 in the placebo group completed the second week of the study. Mean change in the INR from baseline was similar at week 2, -0.18 +/- 0.38 and 0.09 +/- 0.53 (p=0.193), respectively. Gastrointestinal side effects (diarrhea, gas, bloating) occurred in three patients in the olestra group and five in the placebo group (p=0.3). Moderate consumption of snacks containing olestra did not significantly affect the INR (> 0.3 U) at 1 week in patients receiving long-term anticoagulation with warfarin. It does not appear that moderate consumption of these snacks would affect the INR after 2 weeks, but this must be confirmed in a larger sample with adequate power at 2 weeks.

Background: Olestra is a nonabsorbable, energy-free fat substitute. Because it is not absorbed, it may cause digestive symptoms when consumed in large amounts., Objective: To compare the frequency and impact of gastrointestinal symptoms in adults and children who freely consume snacks containing olestra or regular snacks in the home., Design: 6-week, double-blind, randomized, parallel, placebo-controlled trial., Setting: General community., Participants: 3181 volunteers 2 to 89 years of age., Intervention: Households received identical packages labeled as containing olestra corn or potato chips. These packages contained either olestra or regular chips (control)., Measurement: Gastrointestinal symptoms and their impact on daily activities were reported in a daily record., Results: At least one gastrointestinal symptom was reported by 619 of 1620 (38.2%) persons in the olestra group and 576 of 1561 (36.9%) controls (difference, 1.3 percentage points [95% CI, -3.6 to 6.2 percentage points]; P = 0.60). In general, the groups did not differ significantly in the proportion of participants who reported individual gastrointestinal symptoms; however, more controls reported nausea (8.4% compared with 5.7%; difference, -2.7 percentage points [CI, -4.9 to -0.4 percentage points]; P = 0.02). The only difference between groups for the mean numbers of days on which symptoms were reported was that participants in the olestra group had 1 more symptom-day of more frequent bowel movements than did controls (3.7 symptom-days compared with 2.8 symptom days; difference, 0.9 symptom-days [CI, 0.1 to 1.8 symptom-days]; P = 0.04). The groups did not differ in the impact of symptoms on daily activities., Conclusions: Clinically meaningful or bothersome gastrointestinal effects are not associated with unregulated consumption of olestra corn and potato chips in the home.

Olestra is a fat substitute made from sucrose and vegetable oil. Olestra is neither digested nor absorbed, and therefore adds no calories or fat to the diet. Because the gut is the only organ that is exposed to olestra, the potential for olestra to affect gastrointestinal structure and function, and the absorption of nutrients from the gut, has been investigated. Histological evaluations performed after long-term feeding studies have shown no indications that olestra causes injury to the gastrointestinal mucosa. Olestra is not metabolized by the colonic microflora, and has no meaningful effects on the metabolic function of these organisms. Studies of gastrointestinal transit have shown that the consumption of olestra with food does not affect gastric emptying, or small or large bowel transit times. Olestra does not affect the absorption of macronutrients, water-soluble vitamins or minerals. It causes a dose-responsive decrease in the availability of the fat-soluble vitamins A, D, E and K; however, this potentially adverse effect is offset by the addition of vitamins to olestra-containing foods. Olestra has no consistent effect on the amount of total bile acids excreted in the faeces, and therefore probably has no significant effect on bile acid absorption. The occurrence of gastrointestinal symptoms, including diarrhoea, loose stools, gas and abdominal cramping, after consumption of olestra under ordinary snacking conditions is comparable to that following consumption of triglyceride-containing snacks.

The Procter & Gamble Company spent 30 years and an estimated $500 million to bring its non-digestible fat substitute, olestra, to market. The Food and Drug Administration approved olestra as a food additive but requires products containing olestra to carry a warning statement about its potential effects on gastrointestinal function. In obtaining approval for olestra, P&G conducted a lengthy, persistent, and comprehensive campaign to enlist support from members of Congress; FDA staff; and food, nutrition, and health professionals. This campaign raises larger questions about corporate influence on government policies, and the relationships of corporations to health professionals. To address these larger concerns, the author reviews the history of olestra's approval; describes P&G's campaign to obtain support from FDA and Congress, to defend olestra against critics, and to market it to professionals, the press, and consumers; and suggests implications for public health policies.

In 1987, Procter and Gamble Company (Cincinnati, Ohio) petitioned the US Food and Drug Administration (FDA) to amend the food additive regulations to allow sucrose esterified with fatty acids (olestra) to be used as a replacement for conventional fats. The petitioner later restricted its request for use in savory snacks. FDA considered evidence submitted by the petitioner, the opinions of experts, proceedings from the FDA Food Advisory Committee, and public discussion and concluded on January 25, 1996, that olestra was safe for use in savory snacks (eg, salty snacks such as potato chips, corn chips). Olestra is not toxic, carcinogenic, genotoxic, or teratogenic and is neither absorbed nor metabolized by the body, but may be associated with gastrointestinal tract symptoms such as cramping or loose stools. In addition, olestra affects the absorption of fat-soluble vitamins but does not affect the absorption of water-soluble nutrients. The petitioner's studies concluded that when olestra was consumed with foods containing vitamins A, D, E, or K, the fat substitute could have an effect on the absorption of these nutrients. Therefore, FDA is requiring that fat-soluble vitamins lost through absorption be added back to olestra as follows: 170 IU vitamin A per gram olestra, 12 IU vitamin D per gram olestra, 2.8 IU vitamin E per gram olestra, and 8 micrograms vitamin K per gram olestra. As part of the conditions of approval FDA is requiring that the food labels of products containing olestra disclose the vitamin compensation and the potential gastrointestinal effects. FDA is also requiring that further studies examining consumption patterns and the effects of olestra on human beings be conducted.

Context: Olestra, a nonabsorbable, energy-free fat substitute used in snack foods, has been anecdotally reported to cause gastrointestinal (GI) adverse events, although such effects were not expected based on results from randomized trials, in which it was consumed in typical snack patterns., Objective: To determine whether ad libitum consumption of potato chips made with the fat substitute olestra results in a different level of GI symptoms than regular chips made with triglyceride (TG)., Design: Randomized, double-blind, parallel, placebo-controlled trial., Setting: A suburban Chicago, III, multiplex cinema., Subjects: A total of 1123 volunteers aged 13 to 88 years., Intervention: Subjects were given a beverage and an unlabeled, white 369-g (13-oz) bag of potato chips made with olestra or TG during a free movie screening., Main Outcome Measures: Total and specific GI symptoms reported during a telephone interview conducted from 40 hours to 10 days after ingestion; level of potato chip consumption; and satiety level., Results: Of 563 evaluable subjects in the olestra chip group, 89 (15.8%) reported 1 or more GI symptoms, while 93 (17.6%) of the 529 evaluable subjects in the regular TG chip group did so (difference in symptom frequency between olestra and TG, -1.8; 95% confidence interval, -6.2 to 2.7; P=.47). For specific GI symptoms (eg, gas, diarrhea, abdominal cramping), there were no significant differences between olestra and TG chips. Fewer olestra chips were consumed than TG chips (60 vs 77 g [2.1 vs 2.7 oz]; P<.001), with olestra chips receiving lower taste scores (5.6 vs 6.4 on a 9-point scale; P<.001). Consumption levels did not correlate with the rate of symptom reporting in either the olestra or TG group. There was no difference in satiety scores between olestra and TG chips (5.7 vs 5.9 on a 9-point scale; P=.07)., Conclusions: This study demonstrates that ad libitum consumption of olestra potato chips during 1 sitting is not associated with increased incidence or severity of GI symptoms, nor does the amount consumed predict who will report GI effects after short-term consumption of either olestra or TG potato chips.

Olestra is a zero-calorie fat substitute that is neither digested nor absorbed. A randomized, double-blind, placebo-controlled, within-subject, crossover rechallenge study was conducted to compare the occurrence of gastrointestinal symptoms after ingestion of chips made with Olean brand of olestra or conventional triglycerides in subjects who had previously experienced gastrointestinal symptoms they attributed to consuming Olean. A total of 57 male or female subjects received 2 oz of Olean potato chips or triglyceride potato chips at each of four weekly site visits. The occurrence of gastrointestinal effects after product consumption was noted in follow-up telephone interviews 3 to 5 days after each visit. There was no significant difference in the frequency of any gastrointestinal symptoms (abdominal cramping, diarrhea, loose stools) following consumption of Olean chips or triglyceride chips, and the severity of diarrhea, loose stools, and abdominal cramping was similar. We conclude that consumption of a 2-oz serving of Olean chips is no more likely to result in reports of gastrointestinal symptoms than consumption of triglyceride snacks as a part of the usual diet, even in individuals who have claimed intolerance to Olean. The data suggest that subjects who previously experienced symptoms that they attributed to consuming products made with Olean may have mistakenly attributed their symptoms to these products., (Copyright 1997 Academic Press.)

Olestra, a dietary fat substitute, was recently made available to consumers in savory snacks in three cities. Early reports of gastrointestinal complaints attributed to olestra attracted media coverage and fostered confusion among physicians and consumers about the nature of olestra and its effects on the digestive system. We reviewed all published studies of olestra's gastrointestinal effects and all relevant unpublished studies submitted to the Food and Drug Administration. Each study was analyzed by a group of expert gastroenterologists and epidemiologists. The symptoms reported with olestra ingestion are similar to those reported with ingestion of fiber and sorbitol, although the mechanisms involved in changing stool characteristics differ among these food additives. Olestra's effects on stool habit and characteristics are due to its presence in the stool. Large amounts are more likely to induce gastrointestinal symptoms than small amounts. There is no evidence that olestra induces pathological change in bowel function: there is no increased fluid or electrolyte nor is there altered gastrointestinal motility or microflora. Olestra and triglyceride ingestion resulted in a similar frequency of symptoms in normal adults and children and in people with chronic inflammatory bowel disease in remission. Olestra traverses the digestive tract intact to become a stool additive. Some subjects develop a change in bowel habit and stool characteristics due to the presence of more olestra in the stool. These changes resemble those associated with ingestion of sorbitol and fiber., (Copyright 1997 Academic Press.)

Ninety normal healthy adults were given 0, 8, 20 or 32 g/d olestra for 8 wk as part of a diet that provided 1 +/- 0.2 of the recommended dietary allowance (RDA) of vitamins A, D, E and K, folate zinc, calcium and iron. In addition, a 20 microg/d supplement of vitamin D was supplied. The diet provided 15% of energy from protein, 35% from fat and 55% from carbohydrate. The purpose of the study was to determine the dose response of olestra on vitamins D, E and K, carotenoids, vitamin B12, folate and zinc. Circulating concentrations of retinol, carotenoids, tocopherols, 25-hydroxy- and 1,25-dihydroxyvitamin D metabolites, phylloquinone, des-gamma-carboxyprothrombin, prothrombin, folate and hematological parameters were measured biweekly, as were urine concentrations of zinc and gamma-carboxyglutamic acid (Gla). Clinical chemistry, urinalysis and vitamin B12 absorption were measured at wk 0 and 8. Olestra reduced serum concentrations of carotenoids, alpha-tocopherol, 25-hydroxyergocalciferol and phylloquinone in a dose-responsive manner. Olestra did not affect Gla excretion, plasma des-gamma-carboxyprothrombin or prothrombin concentrations, prothrombin time, vitamin B12 absorption, overall vitamin D status or the status of folate or zinc. Laboratory evaluations showed no health-related effects of olestra. Subjects in all groups reported common gastrointestinal symptoms such as loose stools, fecal urgency and flatulence, which were transient and generally mild to moderate in severity. These symptoms did not affect protocol compliance or the ability to measure the potential for olestra to affect nutrient availability.

Olestra is a zero-calorie fat replacement intended to replace 100% of the fat used in the preparation of savory snacks. Olestra can affect the absorption of other dietary components, especially highly lipophilic ones, when ingested at the same time. The potential effects of olestra on the absorption of essential fat-soluble and water-soluble dietary components have been investigated in pigs and in humans. In these studies, subjects were fed daily amounts of olestra up to 10 times the estimated mean intake from savory snacks and the olestra was eaten each day of the studies. In real life, snacks are eaten on average five times in a 14-d period. Olestra did not affect the availability of water-soluble micronutrients or the absorption and utilization of macronutrients. Olestra reduced the absorption of fat-soluble vitamins A, D, E and K; however, the effects can be offset by adding specified amounts of the vitamins to olestra foods. Olestra also reduced the absorption of carotenoids; analysis of dietary patterns showed that in real life the reduction will likely be <10%. Any effect on vitamin A stores caused by a reduction in carotenoid uptake is offset by the addition of vitamin A to olestra foods. Because of the olestra-to-nutrient ratios fed and the nutritional requirements of the test subjects, the effects of olestra on nutritional status of subgroups of the population are unlikely to be different than those measured in the studies. An analysis of lipophilicity showed that olestra is unlikely to significantly affect the uptake of potentially beneficial phytochemicals from fruits and vegetables. Some people eating large amounts of olestra snacks may experience common GI symptoms such as stomach discomfort or changes in stool consistency, similar to symptoms accompanying other dietary changes. These symptoms present no health risks.

One hundred two normal healthy males and females were given 0, 8, 20 or 32 g/d olestra to which had been added graded amounts of vitamins A, D and E for 8 wk in a parallel, double-blind study. The primary purpose of the study was to determine the amounts of vitamins D and E needed to offset the effect of olestra on the availability of these vitamins. Serum concentrations of retinol, carotenoids, 25-hydroxyvitamin D metabolites, alpha-tocopherol, phylloquinone, lipids, ferritin and total iron, iron-binding capacity and hematology parameters, plasma concentrations of des-gamma-carboxyprothrombin and prothrombin, and urinary gamma-carboxyglutamic acid (Gla) excretion were measured biweekly. Clinical chemistry and urinalysis parameters, vitamin B12 absorption, and serum 1,25-dihydroxyvitamin D concentration were measured at wk 0 and 8. Serum concentrations of alpha-tocopherol and 25-hydroxyergocalciferol were restored to control concentration by adding 2.1 mg d-alpha-tocopheryl acetate and 0.06 microg ergocalciferol per gram of olestra, respectively, to the diet. Olestra reduced serum concentrations of 25-hydroxyergocalciferol, carotenoids and phylloquinone in a dose-responsive manner but did not affect Gla excretion, plasma des-gamma-carboxyprothrombin and prothrombin concentrations, overall vitamin D status, vitamin B12 absorption or iron status. Laboratory evaluations showed no olestra-related effects. Subjects in all groups reported mild to moderately severe transient gastrointestinal symptoms. These symptoms did not affect study compliance or the integrity of the data.