University of Iowa Health Science Relations and
Satish Rao, MD, PhD, FRCP
Professor of Internal Medicine
First Published: 2003
Last Revised: October 2003
Peer Review Status: Internally Peer Reviewed

Fructose may be a simple sugar, but what it does to some people is not simple at all. Bloating, abdominal pain, diarrhea, and flatulence are among the discomforts endured by people with fructose intolerance and Irritable Bowel Syndrome (IBS) symptoms.

But relief may be possible. People who complied with a fructose-restricted diet significantly reduced their symptoms, according to a 2003 University of Iowa study. The study was based on patients with fructose intolerance who received oral and written dietary instructions to eliminate most fructose--found in pop, canned foods and candy--from their daily food intake.

"Clearly, there was improvement in the symptoms of patients with fructose-intolerance who complied with the restrictions," said the study's primary investigator Satish Rao, MD, PhD, UI professor of internal medicine and director of neurogastroneterology and gastrointestinal motility.

The investigators tested a group of 80 patients with suspected IBS and found that 30 of them were fructose-intolerant. These 30 individuals were asked to follow a fructose-restricted diet for an average of one year. At the study follow-up, 26 participants were available to report whether they had adhered to the fructose-restrictions. More than half of the group (14 of 24) said they had complied and reported reduced bowel and gastrointestinal symptoms. People who did not comply had no change in their symptoms.

Anything with high fructose corn syrup, a prevalent ingredient in commercially prepared food in the Western diet, can cause problems for people with IBS or fructose intolerance. Soft drinks and chocolate also are culprits. To a lesser extent, fruits and vegetables can be a problem if they are eaten in large or excessive quantities.

Rao pointed out that both patients and physicians should be aware that it is hard to comply with fructose restrictions, so physicians need to explore with patients how best to improve their compliance.

"If someone loves to drink two huge bottles of pop a day, and then they're told 'bad luck, you can't have this pop,' they may not find it easy to make changes," Rao said.

Rao and colleagues intend to study different types of diets to see which are both effective and easy to follow. In addition, there may be other solutions to eliminate the effects of fructose.

"It's understandably hard to have people change their lifestyle, so we're also looking at what we can do other than diet," Rao said.