The fat substitute olestra may cause severe gastrointestinal disease, according to a letter published in the July issue of the Journal of Pediatric Gastroenterology and Nutrition. Dr. Tamar Barlam, of the Center for Science in the Public Interest (CSPI), and Dr. Eric McCloud, of Miller’s Children’s Hospital in Long Beach, California, described two cases involving previously healthy children.

One patient, an 11-year-old girl, developed flatulence, cramps, and foul-smelling diarrhea over a two-week period while eating olestra chips. Those problems diminished when she stopped eating the chips, but she then developed rectal bleeding. A colonoscopy revealed ulcerative colitis, for which she was treated with a steroid, anti-inflammatory medication, and other drugs, according to the letter.

In the second report, a 13-year-old boy developed abdominal distention and constipation within hours of eating a few potato chips containing olestra. He then developed abdominal cramps, severe back pain, explosive diarrhea, and gas. After the boy lost 23 pounds over the next few months, much of his colon was removed.

Both children are now doing well.

“It is impossible to determine that olestra was the cause of the problems that those children suffered,” Barlam said. “But these cases serve as an important reminder of the lack of available data about potentially severe, but less frequent, effects of olestra.”

While the symptoms reported in the new report are more serious than the average reaction to olestra, hundreds of people have reported that they went to the emergency room for treatment of apparent olestra-related cramps or diarrhea, according to CSPI. The FDA has received 20,000 adverse-reaction reports related to olestra. According to CSPI, that is more than the FDA has received for all other additives in history combined.

Two main producers of olestra-containing chips, Procter and Gamble (Fat Free Pringles) and Frito-Lay (WOW chips) are still pressuring the FDA to drop its requirement for a warning notice advising consumers of the possibility of cramps and loose stools. In 2002, Procter and Gamble sold olestra and its factory to another company. Sales of olestra have dropped by about two-thirds over the past several years.

"The new report provides further evidence, if any was needed, that the FDA should do what Canada, Britain, and other companies have done: ban olestra," said Michael F. Jacobson, CSPI executive director. "Allowing it in the food supply just creates misery for far too many people. Procter and Gamble’s own clinical studies in the 1990s demonstrated that olestra could cause cramps, loose stools, and diarrhea."

People who believe they experienced an adverse reaction to olestra should submit a report to CSPI at www.cspinet.org/olestraform.