Hydrogen Breath Test for Fructose Malabsorption
What is Hydrogen Breath Testing?
Hydrogen breath testing is used to diagnose three primary conditions. First, hydrogen breath testing detects sugars like lactose that are not properly digested and metabolized. Secondly, hydrogen breath testing detects sugars like fructose that are not absorbed in sufficient levels. Thirdly, hydrogen breath testing is used to diagnose bacterial overgrowth of the small bowel.
What is the principle of the Fructose Malabsorption Breath Test?
The hydrogen breath test for fructose malabsorption provides clinical information about the digestion of fructose, a predominant sugar in fruit and products containing sweetners like fructose corn syrup. Fructose malabsorption refers to the abnormal processing (absorption) of fructose.
Hydrogen and methane gas are produced in the body from intestinal bacteria. Bacteria ferment sugars such as fructose to hydrogen and/or methane gas. Hydrogen and methane are absorbed by the intestinal mucosa, enter the vasculature, and get transported to the lungs. A change in the level of hydrogen and/or methane gas above 20 parts per million is diagnostic for fructose malabsorption. The majority, but not all malabsorbers produce hydrogen gas. Approximately 15% of patients are methane producers rather than hydrogen producers. These patients will only be properly diagnosed by measuring methane levels. As a result, each breath specimen is measured by Metabolic Solutions for hydrogen and methane.
What causes Fructose Malabsorption?
Fructose malabsorption is the inability for the small intestine to properly absorb fructose, a common sugar found in many prepared foods and soft drinks. Fructose malabsorption occurs due to a limitation in the fructose carrier system which transports that sugar across the intestinal cell membrane. Fructose then enters the colon and because of its osmotic properties, causes a collection of water to enter. Bacteria in the colon ferment fructose to hydrogen, methane, carbon dioxide and short-chained fatty acids. These actions in total may cause cramping, bloating, gas or diarrhea when foods containing fructose are eaten above our capacity to absorb them.
Why should I test for Fructose Malabsorption?
The U.S. Department of Agriculture has found that the ingestion of fructose has increased nearly nine-fold from 1966 to 2003. This increase has been attributed to the practice of adding fructose corn syrup to many drinks, candies and canned foods. Satish Rao, M.D., a gastroenterologist, and colleagues at the University of Iowa suggest that "For people with gastrointestinal symptoms or those who have already been diagnosed with IBS, it is worth raising the question of dietary fructose intolerance." In IBS patients, there is evidence to suggest that more rapid small intestinal transit could deliver unabsorbed nutrients to the colon and hence lead to an increased gas production, causing pain and diarrhea. This may explain the reduced capacity to absorb free fructose in IBS patients. The fructose malabsorption breath test is a quick way to discover if a patient has fructose malabsorption.
What types of patients have Fructose Malabsorption?
Approximately 75% of people are unable to digest a 50-gram load of glucose. It has been reported that a majority of IBS patients have fructose malabsorption. It has not been determined that fructose malabsorption is the cause of IBS but it is postulated that it may cause some of the functional gut symptoms associated with IBS.
What age does Fructose Malabsorption occur?
Fructose malabsorption can affect patients of all ages. There appears to be a spectrum of absorptive capacity of free fructose across populations.
What are the symptoms of Fructose Malabsorption?
- Abdominal cramps
- Abdominal bloating
- Diarrhea
- Gas (flatulence)
- Nausea
How do I treat Fructose Malabsorption?
A fructose-restricted diet is the best way to treat fructose malabsorption. Typically, the following common foods should be avoided:
- Fruit and fruit juices
- Meat products cured in sugar or breaded
- Sweetened beverages
- Honey
- Maple syrup
- Table sugar
- Confectioner's sugar
Two excellent guidelines for more information on what to avoid and what to eat are available for download:
