Fructose Intolerance Breath Test

Fructose is a simple monosaccharide found in many plant foods and is widely used as a sweetening additive in the form of fructose corn syrup, a mixture of glucose and fructose. Its consumption has risen in recent years.

Non-absorbed fructose produces gastrointestinal symptoms in the large bowel when metabolised by colonic bacteria, which may be a 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 (IBS).  Genetic mutations can increase an individual’s susceptibility.

Breath testing is the method of choice for the diagnosis of fructose intolerance.  25 g of fructose is the cut-off dose to investigate fructose malabsorption, with a positive breath test at this dose suggesting poor fructose absorption capacity.  This low level may be regularly consumed in the daily diet, resulting in frequent symptoms of fructose malabsorption.

Fructose 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 IBS.