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!
Photo taken by Branko Gregov; Edited by Isabella Grevov & Lauren Renlund
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
These are a few examples of low and high fructose foods, obtained from Kate Scarlata.7
Diagnosis
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
Symptom Management
Symptoms of fructose malabsorption can be greatly reduced by consuming a diet low in fructose.3 Individuals who malabsorb fructose are commonly also sensitive to other FODMAPs and therefore dietitians typically will recommend trying a low FODMAP diet.8 A low FODMAP diet can help to manage digestive symptoms and identify which foods trigger symptoms. Click here for more information on the low FODMAP diet.
Please note that taking a glucose tablet when eating a high fructose food will not help to decrease digestive symptoms – click here for details of research on this area.
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. It is also essential to receive a diagnosis before trialling dietary changes. Once you have received a diagnosis, a registered dietitian can help you with making dietary changes, such as the low FODMAP diet.
References
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/
8. Shepherd Works, (n.d.). Fructose malabsorption. Retrieved from http://shepherdworks.com.au/disease-information/fructose-malabsorption/
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.
Hi Lauren!
I’m currently on a Low FODMAP diet.. I’m wondering if Fructose malabsorption is in anyway related to this?
If yes, do you have any tips? By the way thanks for this informative article!
Hello! Thanks for commenting. I have updated this article to better reflect recent research. If someone completes the low FODMAP diet and learns that fructose is one of their symptom triggers, then it is likely because they are malabsorbing fructose – the fructose then can reach the large intestine where it can cause trouble and trigger symptoms. I would recommend to follow the tips in my Introduction to the Low FODMAP Diet page 🙂 http://www.laurenrenlund.com/introduction-low-fodmap-diet/