Some people cannot absorb fructose well genetically and can get gut
symptoms like IBS, abdominal pain and bloating especially after fruit
and fruit juice. This is a simple challenge breath test for fructose
malabsorption to see if you produce more hydrogen and methane than you
should after eating fructose.
Note: the fructose used is derived from corn. If you wish, you can use
an alternative fructose type derived from a non-grain
- 25g in 250ml water as below. It must be pure fructose though and not contain any other carbohydrate which would give a false result.
Note: you should also consider candida overgrowth if this sounds like
you since candida yeast feeds on sugars and sugary drinks. You can test
for candida with a simple test
, or the more comprehensive
Here is the data sheet from Biolab:
is a simple monosaccharide which is found in many plant foods. It is
also used as a sweetening additive in the form of fructose corn syrup,
a mixture of glucose and fructose. Its consumption is, in general,
rising among the population. Setting aside the 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 GLUT5, which is used by fructose to cross the intestinal
epithelium . Non-absorbed ffructose 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 underlie 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 (A149P and
A174D); 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 used a 50 gm dose of fructose,
which often exceeded the absorptive capacity for fructose in normal
individuals. 25 gm 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 .
malabsorption should be considered in subjects with unexplained
gastro-intestinal symptoms, especially after consumption of fruit and
fruit drinks. Fructose malabsorption may also contribute to the
symptoms of irritable bowel syndrome.
Subjects who do not absorb fructose (a monosaccharide normally present
in food) produce hydrogen and perhaps methane as the carbohydrate
passes into the lower gut. A fructose breath test is positive if either
the hydrogen peaks by >20 ppm compared to the basal sample or if
the methane peaks by >12 ppm compared to the basal sample.
patient is given 25 gm of fructose in 250 ml of water and alveolar air
samples are collected at baseline and every 60 minutes for 3 hours (3
samples in all).
Jones HF, Butler RN, Brooks DA. Intestinal fructose transport and
malabsorption in humans. Am J Physiol Gastrointest Liver Physiol.
2. Kyaw MH, Mayberry JF. Fructose malabsorption: true condition or a
variance from normality. J Clin Gastroenterol 2011;45:16-21.
3. Ali, M, Rellos P, Cox TM. Hereditary fructose intolerance. J Med
4. Corpe CP, Burant CF, Hoekstra JH. Intestinal fructose absorption:
clinical and molecular aspects. J Pediatr Gastroenterol Nutr