Sorbitol, a sweetener used in sugar-free products such as chewing gum, can cause intestinal problems and severe weight loss, according to a report in BMJ, formerly the British Medical Journal.

Researchers said it has laxative properties and is poorly absorbed by the small intestine.

In at least two patients, that led to chronic diarrhea, pain and up to a 20 percent loss of body weight.

A 21-year-old woman chewed large amounts of sugar-free gum, accounting for a total daily dose of 18 to 20 grams of sorbitol. A 46-year-old man reported chewing 20 sticks of sugar-free gum and eating up to 200 grams of sweets each day, which together contained around 30 grams of sorbitol.

After both patients started a sorbitol-free diet, diarrhea subsided, normal bowel movements resumed and weight gain was achieved, the report said.

The authors of the study said that people with intestinal problems may not think of sweeteners because possible side effects are usually found only within the small print on food packages.

They said the investigation of unexplained weight loss should include detailed dietary history with regard to foods containing sorbitol.