Olestra has recently gained attention as an energy-free fat substitute in snack foods such as potato chips and crackers. A mixture of sucrose esters of long-chain fatty acids, olestra is neither digested nor absorbed. Early anecdotal reports suggested that diarrhea and abdominal pain result from ingesting olestra, but these reports have not been substantiated by controlled testing. Sandler and associates evaluated the frequency of gastrointestinal symptoms and their impact on daily living in persons who consumed olestra potato chips over a six-week period.

Participants were recruited by telephone to participate in this randomized, double-blind, placebo-controlled study. Only households in which at least one half of the members consumed corn chips or potato chips four or more times a month were eligible for the study. Households that met the study criteria were randomized to the olestra or the control group. All members in the household received the same study treatment, and an adult household contact was designated to report to the study site each week. Household contacts from both groups selected from a variety of chip products that were labeled as regular or as containing olestra. However, only those in the study group received products actually containing olestra; those in the control group received regular products, despite what the label showed. All participants were shown the labeling information indicating that olestra could cause gastrointestinal side effects. Participants recorded the amount of regular and olestra chips eaten, how many gastrointestinal symptoms occurred and how the symptoms affected their activities.

A total of 3,181 persons were included in the analysis, with 1,620 in the study group and 1,561 in the control group. Demographic information, educational levels and income levels were similar between groups. Product consumption was slightly lower in the olestra group, but weekly consumption between groups was consistent. The frequency of gastrointestinal effects did not differ significantly between groups. The incidence of diarrhea and cramping was the same between groups. However, participants who thought they were eating olestra chips were more likely to report gastrointestinal symptoms. And among men, the occurrence of cramping was actually higher in the control group.

Because participants selected their own snacks and were able to consume the snacks at home, the study simulated natural circumstances. This finding is clinically important for physicians whose patients report gastrointestinal effects after consuming olestra. Another cause for their discomfort should be sought. Consumers may be attributing these symptoms to olestra in error.

The authors conclude that consuming olestra within the confines of their study did not result in clinically meaningful gastrointestinal symptoms. However, patients who report these symptoms in association with consuming olestra should be evaluated further to identify the causes for their complaints.

editor's note: In an editorial in the same issue, Spiro emphasizes that the authors have a relationship with the manufacturer of olestra. They hedged the issue of side effects by evaluating only those considered “clinically significant” or “bothersome.” Clearly, increased bowel movements have been documented in persons eating olestra chips. Spiro concludes that potato chips containing olestra will delight overweight persons who will think that they are “evacuating” extra calories.—R.S.