Topic: Irritable Bowel Syndrome (IBS), June 2000

Dr. Lee:
A viewer with IBS also experiences sudden and violent diarrhea after eating food that contains MSG. What are your thoughts on MSG intolerance?

Dr. Marks:
MSG certainly can be the cause of gastrointestinal symptoms, but sensitivity to MSG is not part of irritable bowel syndrome. Nevertheless, dietary intolerances to specific foods can mimic irritable bowel syndrome.

For example, many people are intolerant of lactose, the sugar in milk. In some individuals, even small amounts of milk can cause symptoms that mimic irritable bowel syndrome. Therefore, testing for lactose intolerance or a trial of strict elimination of lactose from the diet may be necessary in patients in whom a diagnosis of irritable bowel syndrome is being considered.

Individuals also may be intolerant of sucrose and may develop symptoms (diarrhea and cramps) that can mimic irritable bowel syndrome when they drink beverages like sodas that are sweetened with corn syrup which is high in sucrose.

Sorbitol is another example of a sweetener used in reduced calorie foods, for example, sugar-free chewing gum. It also is used in prepared foods and for diabetics. Intolerance to sorbitol may cause irritable bowel-like symptoms as well.