Hello food friends! Today I have a special blog post for you. This is the first guest post on my blog. It was written by one of my nutrition student volunteers, Isabella Gregov. I reviewed and edited the post, and I am so excited to share it today. Get ready to learn all about fructose malabsorption!
When I tell people that I have fructose malabsorption, the inevitable follow-up question is, “what does that mean?” If you have never heard of fructose malabsorption before and are wondering the same thing, or if you have just been diagnosed and are looking for more information, here is a good place to start!
What is fructose malabsorption?
Fructose is a simple sugar found in foods such as fruit, honey, and high-fructose corn syrup (glucose-fructose).4 Keep in mind that fruits and vegetables that are high in fructose are still excellent sources of nutrients and should not be avoided unless you have a food intolerance.
Fructose malabsorption occurs when the small intestine doesn’t absorb all of the fructose you consume.1 This unabsorbed fructose becomes a feast for the bacteria in your large intestine, producing gases and causing symptoms such as bloating, flatulence, diarrhea and abdominal cramps.2 The severity of symptoms, along with the amount of fructose that can be tolerated, varies between individuals.
It is important to note that fructose malabsorption may also be referred to as fructose intolerance. However, the condition is very different from hereditary fructose intolerance (HFI). HFI is a rare genetic condition in which an enzyme required to break down fructose does not function properly.5 Symptoms are severe and consumption of fructose leads to fructose toxicity.5
Fructose malabsorption may be diagnosed using the hydrogen breath test.1 Certain gases produced by the bacteria that feed on unabsorbed fructose can be measured on the breath. If levels of hydrogen rise beyond a specified peak amount following the consumption of pure fructose, the patient will be diagnosed with fructose malabsorption.4
However, recent research has shown that the hydrogen breath test is not as reliable as once thought.6 Completing an elimination diet under the guidance of a dietitian may be more effective in identifying whether or not fructose malabsorption is the cause of your symptoms.6 Elimination diets can also help you determine how much fructose you can consume before experiencing symptoms.
The causes of fructose malabsorption are not fully understood. Scientists are currently investigating the role of certain fructose transporters in the development of fructose malabsorption.1 Since fructose transporters allow the small intestine to absorb fructose, it is thought that defects in certain transporters may reduce fructose absorption.1
Symptoms of fructose malabsorption can be greatly reduced by consuming a diet low in fructose.3 Reducing the amount of fructans (essentially long chains of fructose molecules) may also improve symptoms.3
Studies also suggest that consuming fructose along with glucose, another simple sugar, aids the absorption of fructose and reduces symptoms.1 For this reason, table sugar, which is a combination of glucose and fructose, may be tolerated. Certain fruits that contain glucose and fructose in roughly equal amounts may also be tolerated by some individuals.1
What to Do Now
Please see your doctor if you are experiencing digestive symptoms. It is not recommended to cut groups of food out of your diet on your own, as it puts you at risk for nutrient deficiencies. If you are struggling with digestive symptoms and/or fructose malabsorption, a Registered Dietitian can help you identify dietary triggers for your symptoms and provide tips on maintaining a low-fructose diet. If your symptoms are improved but not completely alleviated by a low fructose diet, your dietitian may help you implement the low FODMAP diet.
1. Ebert, K. & Witt, H. (2016). Fructose malabsorption. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4755956/
2. Hamilton Health Sciences (2007). Your child’s diet with dietary fructose intolerance (DFI). Retrieved from http://www.hamiltonhealthsciences.ca/documents/Patient%20Education/DFI-trh.pdf
3. Shepherd, S. J. & Gibson, P. R. (2006). Fructose malabsorption and symptoms of irritable bowel syndrome: Guidelines for effective dietary management. Retrieved from http://sacfs.asn.au/download/SueShepherd_sarticle.pdf
4. Skoog, S. M. & Bharucha, A. E. (2004). Dietary fructose and gastrointestinal symptoms: A review. Retrieved from http://www.bashaar.org.il/files/101022005111814.pdf
5. U.S. National Library of Medicine. (2017). Hereditary fructose intolerance. Retrieved from https://ghr.nlm.nih.gov/condition/hereditary-fructose-intolerance#diagnosis
6. Yao, C. K., Tuck, C. J., Barrett, J. S., Canale, K. E. K., Philpott, H. L., Gibson, P. R. (2016). Poor reproducibility of breath hydrogen testing: Implications for its application in functional bowel disorders. Retrieved from http://journals.sagepub.com/doi/full/10.1177/2050640616657978
7. Scarlata, S. (2017). Low and high FODMAP diet checklists. Retrieved from http://www.katescarlata.com/lowfodmapdietchecklists/
About the Guest Author
Isabella Gregov is majoring in Applied Human Nutrition at the University of Guelph. She has first-hand experience living with various types of gastrointestinal problems and specialized diets. She is passionate about sharing her knowledge and experiences and helping others suffering from dietary complaints. Isabella hopes to earn her degree and complete an internship to become a Registered Dietitian.