Newswise — In this week’s British Medical Journal, doctors warn of severe weight loss from excessive consumption of sorbitol, a widely used natural sweetener in “sugar-free” products such as chewing gum and sweets.

Sorbitol belongs to the polyalcohol class of sugar-free sweeteners, along with mannitol and xylitol, that in small amounts are useful as sweeteners because they have a lower glycemic index than sugar. These sweeteners are not calorie-free; they are useful for people with diabetes who are trying to decrease spikes in blood sugar levels. Sorbitol is made in small amounts by the body and thus can be considered “natural.”

Sorbitol, however, has laxative properties and is poorly absorbed by the small intestine, so weight loss from using excessive amounts of sorbitol is not good for one’s health. It can cause so-called “osmotic diarrhea,” which is the type of loose stool that results from using too much magnesium salt laxatives like milk of magnesia. This diarrhea would interfere with proper nutrient absorption over time, so it is not recommended as a weight-loss strategy (even though some patients with eating disorders have attempted to use laxatives for this purpose).

The doctors’ advice follows the cases of two patients with chronic diarrhea, abdominal pain and severe weight loss. Although extensive investigations were carried out, the final diagnosis was only established after detailed analysis of eating habits.

On questioning, both patients admitted consuming substantial amounts of sugar-free gum and sweets.

The first patient (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 (one stick of chewing gum contains about 1.25g sorbitol). The second patient (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 body weight returned to a healthier range.

As possible side effects are usually found only within the small print on the labels of foods containing sorbitol, consumers may be unaware of its laxative effects and fail to recognize any link to their gastrointestinal problems, write the authors.

In conclusion, they say, these cases demonstrate that sorbitol consumption can cause not only chronic diarrhea and functional bowel complaints but also considerable unintended weight loss (about 20 percent of usual body weight). Thus, investigation of unexplained weight loss should include detailed dietary history with regard to foods containing sorbitol or other polyalcohol sugar substitutes such as mannitol and xylitol.

A free PDF copy of these case reports with discussion is available for download here:

Severe weight loss from excessive sorbitol intake from sugar-free chewing gum