Excessive consumption of sugar-free gum, which has a laxative side effect, can lead to diarrhea and unintended weight loss which can pose a health risk.

German researchers writing in the British Medical Journal warn that excessive amounts of sugar-free chewing gum can raise unexpected health concerns like diarrhea and severe weight loss.

The researchers cited two cases in their article, of a man and a woman who chewed around 20 sticks of gum daily, only to become mysteriously ill, BBC News reports.

One 21-year-old woman was admitted to hospital after she had lost around 11 kilos within eight months. The symptoms she presented were diarrhea and stomach pain and she had become underweight.

She was submitted to tests in a search for the reason of her condition before doctors realized that her habit of chewing gum throughout the day was to blame.

In the second case, a 46-year-old man was admitted to hospital after having lost 22 kilos over a year. He too suffered from diarrhea. He too consumed excessive amounts of sugar-free chewing gum.

Dr. Juergen Bauditz, from the Department of Gastroenterology at Charite University Hospital in Berlin, and colleagues said sorbitol, a sweetener used in chewing gum and sweets, was the cause for their severe weight loss.

Each stick of chewing gum has around 1.25g of the sweetener. The two patients were found to consume between 20 and 30g of sorbitol per day, as they frequently replaced the piece they were chewing.

The researchers emphasize that consumers often do not take the precaution of reading the small print on packaging, thus remaining unaware of possible side effects they are exposing themselves to.

Industry representatives on the other hand responded that the sorbitol in chewing gum is a safe ingredient, also found in fruits such as pears, plums, apricots, peaches and apples.

“The safety of sorbitol has been thoroughly reviewed by health and regulatory bodies, including the WHO/FAO Joint Expert Committee on Food Additives,” a Wrigley Company representative was quoted as saying by the BBC.

Bauditz and colleagues said consumers are unaware that sorbitol has a laxative effect and that excess consumption can lead to stomach problems and damaging weight loss.

The two patients recovered and gained back weight after they stopped chewing gum, the researchers said.

While sugar-free chewing gum may a risky laxative effect on some people, the American Dental Association bestowed its Seal of Acceptance to Wrigley sugar-free gums Orbit, Extra and Eclipse in September 2007, certifying that the products help prevent cavities, reduce plaque acid and strengthen teeth.

The German researchers did not comment whether their patients had an excellent dental condition.