THURSDAY, Jan. 10 (HealthDay News) -- Chewing too much sugar-free gum containing the artificial sweetener sorbitol can cause diarrhea leading to potentially dangerous weight loss, German physicians report.

The cases of a 21-year-old woman who suffered diarrhea that caused her to lose about 24 pounds and a 46-year-man who lost approximately 46 pounds because of diarrhea were mysteries until the doctors asked about their chewing habits.

Both were found to be consuming a lot of sorbitol, primarily from chewing gum, said Dr. Herbert Lochs, professor of internal medicine at Humboldt University in Berlin, and one author of the report.

The answer solved the mystery, since heavy consumption of sorbitol has long been associated with a risk of diarrhea, Lochs said.

"There have been case reports earlier, as far back as the 1980s," he said. "These were people who did not have malabsorbtion and malnutrition."

The risk is not as great for consumers in the United States, said Dr. Bret Lashner, a gastroenterologist who is professor of medicine at the Cleveland Clinic, since sorbitol is rarely used in chewing gum here. The preferred artificial sweetener for chewing gum and candy here is aspartame, sold as NutraSweet, Lashner said.

"NutraSweet and saccharin are safe," he said. "Sorbitol is not safe. People should look at the labels to see if they are getting something with sorbitol."

The new findings are published in the Jan. 12 issue of the British Medical Journal.

The two people seen by Lochs and Dr. Juergen Bauditz, a gastroenterologist at the University of Berlin, were consuming sorbitol-containing chewing gum with gusto -- 15 to 20 sticks a day, containing up to 20 grams of the sweetener, for the woman, and 20 sticks of gum and up to 200 grams a day of artificially sweetened candy for the man.

Both were visiting the bathroom 10 or more times a day, and both underwent extensive laboratory testing and physical examinations that left the cause unknown -- until the doctors asked about their chewing habits.

Mystery solved. After the woman stopped chewing gum, she was discharged from the hospital, with just one bowel movement per day. A year later, she had regained 15 pounds. It was the same story for the man -- one bowel movement a day and a weight gain of 11 pounds six months after the gum-chewing ended.

How much sorbitol is safe? It's hard to say, Lochs said. "We thought of trying in a group of healthy people to determine the limit in a majority of cases, but this has not been done yet," he said.

It's not a big issue for the majority of European gum-chewers, Lochs said. "If they don't have symptoms, they should not worry," he said. "If they have diarrhea, they should not chew gum for a while so that the cause can be diagnosed."

American gum-chewers who have diarrhea can mention the habit to their physicians, Lashner said. "Certainly, all doctors are aware of this," he said of the sorbitol connection.

The U.S. Food and Drug Administration says the danger of diarrhea is associated with consumption of more than 50 grams of sorbitol daily.

More information

The Calorie Control Council describes the advantages and disadvantages of sorbitol.

SOURCES: Herbert Lochs, M.D., professor of internal medicine, Humboldt University, Berlin, Germany; Bret Lashner, M.D., professor of medicine, Cleveland Clinic; Jan. 12, 2008, British Medical Journal

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