Is fructose intolerance part of the IBS puzzle? Some new research has looked at the role that ingesting foods that contain fructose, a type of sugar found in fruits and some vegetables, has on unpleasant digestive symptoms. An enzyme deficiency that causes toxic symptoms when fructose containing food is ingested is the formal explanation about fructose intolerance. A positive finding for fructose intolerance would be a rise in breath hydrogen.
Fructose intolerance is a condition where the body has difficult digesting and using fructose and fructose-containing foods. It is treated by complete elimination of fructose and sucrose from the diet. For these people eating lactose can cause symptoms of bloating, stomach cramps, loose stools, nausea and flatulence. A much less well known condition, although similar to lactose intolerance, is fructose malabsorption.
In fructose malabsorption a persons ability to absorb fructose, fruit sugar, is impaired. This results in fructose passing through the intestines and being fermented by bacteria, causing both gastrointestinal symptoms (abdominal bloating/cramps, constipation, loose stools, diarrhea or flatulence) and increased proliferation of certain intestinal bacteria and yeast which metabolise fructose.
Sensitivity to sugars like lactose, fructose and sorbitol is largely undiagnosed, but responsible for stomach bloating and intestinal distress in millions. Fructose malabsorption is not to be confused with hereditary fructose intolerance, a potentially fatal condition in which the liver enzymes that break up fructose are deficient. Fructose intolerance is caused by an inherited mutation in the aldolase B gene (ALDOB). As a result, fructose accumulates in the liver, kidney, and small intestine and the body is unable to convert its energy storage material (glycogen) into glucose.
Fructose malabsorption is diagnosed via a hydrogen breath test. It is a similar test as used to diagnose lactose intolerance. Breath hydrogen measurements are taken fasting, 25 grams of fructose is administered and breath hydrogen levels are monitored regularly for 2 – 3 hours. Though the touted health benefits may exist, sufferers of fructose malabsorption will likely find no difference between these new breads and traditionally prepared breads in alleviating their symptoms because inulin is a fructan, and, again, consumption of fructans should be reduced dramatically in those with fructose malabsorption in an effort to appease symptoms.