Research by a Johns Hopkins Bayview Medical Center physician concluded that potato chips made with olestra don't cause any more digestive problems than regular-fat potato chips and, despite containing only half the calories, are just as filling. Olestra, a non-absorbable fat substitute, has been making news headlines since its approval by the FDA two years ago for use in snack products. It has been criticized for causing abdominal cramping and loose stools, based on two clinical studies in which subjects were required to consume olestra at every meal for 56 consecutive days.

According to a Jan. 14 Journal of the American Medical Association article, the study challenges past findings by looking at olestra under more normal circumstances. "This was the first study of its kind on the fat substitute. Instead of looking at mass consumption of olestra, we looked at what happens to people when they consume it under conditions typical for the use of snack foods," says lead researcher Lawrence Cheskin, a gastroenterologist and director of both the Division of Digestive Diseases and the Weight Management Center at Hopkins Bayview.

In this unprecedented double-blind study, 1,100 people were selected to participate in a potato chip taste test while watching a movie of their choice at a multiplex cinema in Chicago. Half were given chips made with olestra; the other half were given regular-fat potato chips. While the setting was unique for a clinical trial, the study was structured to meet rigorous controlled clinical trial standards. Within four days of the study, participants were interviewed by an independent marketing firm. Nearly 16 percent who ate the olestra chips reported experiencing gastrointestinal symptoms. However, nearly 18 percent said they had gastrointestinal symptoms after eating the regular-fat chips.

In addition, there was no indication of increasing symptoms with higher consumption in either test group. These similar results confirm other, relatively recent findings that digestive symptoms are quite common in the general population.