Are you Fructose intolerant?
Fructose is a simple monosaccharide which is found in many plant foods, most fruits and it is used as a sweetening agent, an additive in glucose fructose corn syrup which is a mixture of glucose and fructose. Its consumption is in general rising among the population due to the increase in the number of processed sweetened foods. Setting aside this condition of “hereditary fructose intolerance” which is relatively rare it is possible for dietary intake of fructose to overload the enterocytes. This is consistent with the limited absorption capacity of the enterocyte transporter gluto5, which is used by fructose to cross the intestinal epithelium. Non absorbed fructose produces gastrointestinal symptoms from its metabolism by colonic bacteria, which may be an undiagnosed cause of recurrent abdominal pain. It has also been suggested that fructose malabsorption may result in the gastrointestinal symptoms seen in patients with irritable bowel syndrome.
The most common mutations responsible for fructose intolerance in northern European populations are on the Aldolase B gene AI49P and AI74D however these mutations only account for 80% of cases and give information as to susceptibility, rather than clinical symptoms. Breath testing is therefore the method of choice for the diagnosis of fructose intolerance. Earlier protocols use a 50 gram dose of fructose which often exceeds the absorptive capacity for fructose in normal individuals. 25 grams appears to be the cut off dose to investigate fructose malabsorption, with a positive breath test at this dose suggesting abnormally low capacity to absorb fructose. This low level may be difficult to exclude from the daily diet resulting in symptoms of fructose malabsorption. Fructose malabsorption should be considered in subjects with “unexplained gastrointestinal symptoms” especially after consuming fruit and fruit drinks. Fructose malabsorption may also contribute to the symptoms of irritable bowel syndrome.
What does the breath test involve? The patient should not have eaten slowly digesting foods such as high fibre foods like beans or bran or whole grain foods the day before the test and they should have fasted for 12 hours prior to the test with only water to drink. It is ideal to stop eating at 8:00 PM and do the test at 8:00 AM the following morning to minimize inconvenience to your day. Alcohol should not be consumed in the previous 24 hours. Vigorous exercise, smoking or sleeping should be avoided immediately before or at anytime during the test protocol. For the breath test the patient is given of Lactulose in 200 mils of water and air samples are collected at baseline and every 60 minutes for three hours so there is 3 sample test tubes in total. If the patient is a child, the dose of Lactulose is reduced to 1 gram per kilo of body weight. The laboratory sends out everything you need to do this test to your home and it can be posted back to the UK.
How I interpret the results. In subjects who do not fully absorb fructose there is abnormally high production of hydrogen and sometimes methane as the Lactulose passes into the lower small intestine. A fructose breath test is positive if either the hydrogen peaks by more than or equal to 20 parts per million compared to the Basel sample or if the methane peaks by greater than or equal to 12 parts per million compared to the Basel sample. The results are measured by gas liquid chromatography in the laboratory in the UK.
A full face to face consultation is required prior to having this test done please contact me to find out more. I can order it for you. 0868439979 or www.gowithyourgut.ie
