Fructose malabsorption may be caused by deficient fructose carriers in the small intestine’s enterocytes. This results in an increased concentration of fructose in the entire small intestine. Fructose is a sugar that is found in many foods, usually fruits, honey, processed foods and foods with high fructose corn syrup and even some vegetables. Fructose is also found in table sugar, comprising 50% of it, with the other component being glucose.

Some people cannot completely absorb fructose in their small intestine. The excess, undigested fructose attracts water, often leading to diarrhoea. Additionally, the undigested fructose is then carried to the large intestine or colon, where normal bacteria rapidly break it down. The breakdown of fructose in the large intestine causes bloating, gas, and other symptoms.

  • What are the symptoms of fructose malabsorption?

    Patients suffering from fructose malabsorption experience a variety of symptoms, including:

    • Diarrhoea

    • Abdominal cramps

    • Bloating

    • Gas

    • Nausea, and sometimes, vomiting

  • What is a hydrogen and methane breath test for fructose malabsorption?

    A hydrogen and methane breath test is a reliable, non-invasive test for fructose malabsorption. Following a 12-hour fast and 12-hour dietary prep, the fructose malabsorption breath test measures the breakdown of a specific amount of fructose over the course of time by capturing breath samples at regular 40 minute intervals. In a person with fructose malabsorption, the fructose will not be completely absorbed in the small intestine, so it will reach the colon, where bacteria will break it down to hydrogen or methane that will be absorbed into the blood and will reach the lungs. Larger than normal amounts of exhaled hydrogen or methane measured during a breath test indicate that you aren’t fully digesting and absorbing fructose and may suffer from fructose malabsorption.

  • Triggers

    Overuse of high fructose foods (especially those sweetened by high fructose corn syrup), bacterial abnormalities in the gut, inflammation, stress


This site is protected by reCAPTCHA and the Google
Privacy Policy and Terms of Service apply.

0161 302 7777


Contact Us

Please call us now on 0161 302 7777. You can email us at:


Contact Us

Please call us now on 0161 302 7777. You can email us for out of hours support too: