GROUP ASKS FDA TO PULL OLESTRA OK : 20% IN STUDY HAVE PROBLEMS WITH FAKE FAT.

Byline: Marian Burros The New York Times

A consumer group has asked the Food and Drug Administration to withdraw its recent approval of a fat substitute, olestra, on the basis of a study that found that 20 percent of people who ate chips made with the product had gastrointestinal problems, 3 percent of them severe.

The Center for Science in the Public Interest, which hired a market research firm to conduct the study in the three test markets where the potato and tortilla chips are being sold by Frito-Lay, has also asked the company to remove the product voluntarily from the market. Frito-Lay is selling the chips under the brand name Max in Eau Claire, Wis., Grand Junction, Colo., and Cedar Rapids, Iowa,

Lynn Markley, a spokeswoman for Frito-Lay, said the company ``would never make any products that would intentionally cause people to become sick,'' and added, ``We are monitoring it closely.''

Markley said that in the 10 weeks the chips had been on the shelves, only 67 people had complained to the company, with symptoms no more serious than those experienced by some people when they eat beans or spicy food.

The drug agency said it was eager to see the center's data. Dr. Michael Friedman, the agency's deputy commissioner for operations, said the center's executive director, Dr. Michael Jacobson, ``has raised important scientific questions that need definitive answers.''

Some gastrointestinal problems were expected when olestra, which is being marketed under the brand name Olean, was approved.

According to tests done by Procter & Gamble, which manufactures olestra, a statistically significant number of healthy people who ate less than an ounce a day of potato chips containing olestra developed a wide range of gastrointestinal problems. More detailed figures were not available because the tests were based on numerous small studies.

As a result of the findings, foods containing the fat substitute are required to carry a warning label: ``This product contains olestra. Olestra may cause abdominal cramping and loose stools.'' Procter & Gamble must also forward consumer complaints to the drug agency.

In the study for the center done by Bruskin Goldring, 500 households were randomly selected and questioned by telephone about their experience with the chips. The survey found 135 households in which people had tried Max chips. (The margin of sampling error was plus or minus four percentage points.) Forty-eight people in 27 of those households experienced adverse effects.