Irritable bowel syndrome (IBS) is a disorder characterized by abdominal pain or discomfort, along with chronic diarrhea, constipation, or both—either mixed or in alternation. Its impact ranges from mild inconvenience to severe debilitation. The economic burden of IBS to our country was estimated at $30 billion yearly in 2007. It affects 25-45 million people in the US, about 10-15% of the population worldwide. Studies indicate IBS is rare in underdeveloped countries and increases as countries (and their diets) become westernized. Women are twice as likely as men to be afflicted with IBS.
Recurrent abdominal pain (RAP) isn’t restricted to adults. It’s been estimated that up to 25% of school-aged children worldwide suffer from RAP, and that about 60% of RAP is actually IBS.
Although factors such as stress, hormonal fluctuations, and food allergies and sensitivities can trigger IBS and RAP, their causes are unknown.
However, research done in the last twenty years indicates that for anywhere from one-third to half of those with these problems, a restricted fructose diet will alleviate symptoms. It is thought that these people suffer from a condition called “fructose malabsorption.”
Unlike glucose, which is easy to absorb in our intestines, fructose absorption is more complicated. Each of us seems to have a limit on how much fructose we can absorb, and this capacity varies considerably from one person to another. Fructose that doesn’t get absorbed stays in the intestines where it can feed colonic bacteria, draw water into the intestines, and promote mucosal biofilm formation. These factors can in turn lead to gas, bloating, abdominal discomfort, nausea, disturbed bowel function, and, occasionally, gastroesophageal reflux (GERD), the classical features of fructose malabsorption.
After several earlier studies had established the benefits of a fructose-restricted diet in treating IBS and RAP, Dr. Robert E. Gomara, at the Department of Pediatrics at New York Medical College in Valhalla, New York, conducted a randomized controlled trial with children who were experiencing chronic abdominal pain.
The standard laboratory test for identifying fructose malabsorption is the hydrogen breath test (HBT). The children in the Gomara study took this test. When challenged with 15 grams of fructose, 30% tested positive for fructose malabsorption. When challenged with 45 grams, 62% tested positive. (A standard 22-oz high fructose corn syrup-sweetened soft drink contains 30-40 grams of fructose, while a medium apple contains about 9 grams.)
Eleven children who tested positive followed a fructose-restricted diet. Nine experienced rapid improvement in gastrointestinal symptoms. When they were rechecked two months later, their improvements had been sustained.
Although “fructose malabsorption” is often used interchangeably with “fructose intolerance,” “fructose intolerance” should really be reserved to describe a genetic mutation that makes people unable to metabolize fructose. Sometimes called “hereditary fructose intolerance,” this condition shows up in infancy and is relatively rare.
If you suffer from bowel distress, it would certainly be sensible to try following a fructose-restricted diet, many examples of which are available on the internet.
- International Foundation for Gastrointestinal Disorders. Facts About IBS. Last updated November 24, 2016.
- Lembo AJ. The clinical and economic burden of irritable bowel syndrome. Practical Gastroenterology. September 2007;31(suppl):3-9.
- Corsetti M. The global impact of IBS: time to think about IBS-specific models of care? Therapeutic Advances in Gastroenterology. September 2017;10(9):727-736.
- Chumpitaz BP. Underlying molecular and cellular mechanisms in childhood irritable bowel syndrome. Molecular and Cellular Pediatrics. Published online February 2016.
- Helms S. Fructose malabsorption: a possible factor in functional bowel disorders. U.S. Pharmacist. December 2011;36(12):41-44.
- Gibson PR. Review article: fructose malabsorption and the bigger picture. Alimentary Pharmacology & Therapeutics. February 2007;25(4):349-363.
- Gomara RE. Fructose intolerance in children presenting with abdominal pain. Pediatric Gastroenterology and Nutrition. September 2008;47(3):303-308.