Fructose
Malabsorption
FAQ
Frequently asked questions
about a shitty medical condition
Illustration adapted from Amanda Oleander
π What is fructose?
Fructose is a naturally occurring simple sugar. You can find it in fruit, hence the name fructose, vegetables, or honey. Fructose also makes up 50% of table sugar, sucrose, the other half being another simple sugar, glucose.
𧨠What is fructose malabsorption?
FM occurs when your body isn't able to absorb fructose in the small intestine and send it to the liver. Instead, fructose stays in the gut where it is not supposed to be and gets fermented by your gut microbiota. That disrupts the normal digestive process.
π© What are the symptoms?
Diarrhea or loose stools, gas, bloating, abdominal pain, chronic fatigue, headaches, nutritional deficiencies, possibly depression. Some also report constipation.
π¬ How do I get tested?
With a hydrogen breath test. Procedure: Arrive on empty stomach, brush teeth at doctor's office, drink fructose solution, breathe every 15 minutes into a plastic bag for 4 hours, discuss results. Don't get surprised if SIBO, small intestinal bacterial overgrowth, is diagnosed along with FM.
π©Ή What's the treatment?
As of 2020, there is no cure but it can be managed by strictly following a low- or no-fructose diet, and taking a xylose isomerase enzyme before a meal containing fructose. Brand names for xylose isomerase are Fructaid and Lutomerase.
π₯ What can I eat?
One of the best strategies, besides seeing a specialist, is to get a mobile app with a database of foods and their fructose content. For instance Food Intolerances or Monash University FODMAP Diet. A lesser-known option that is safe is to get nutritionally complete powder food. For example Super Body Fuel (except for strawberry flavor). For other brands, be sure to check their list of ingredients.
π§ Anything else to avoid besides fructose?
Yes, the general advice is to minimize or eliminate fructans and polyols. However, test the degree of your individual sensitivity. Fructans are chains of fructose molecules and are mainly found in garlic, onion, and wheat. Polyols are sugar alcohols and include sorbitol, mannitol, maltitol, xylitol, erythritol, isomalt.
πͺ Can I eat sweet things?
Yes, but only those sweetened with glucose ie. dextrose, lactose, monk fruit extract. Avoid foods sweetened with fructose, table sugar ie. sucrose, honey, high fructose corn syrup, which all contain fructose. This is not an exhaustive list, check your fructose diet mobile app for more.
π Do I need to go gluten-free?
No, unless you are a celiac or have a gluten sensitivity unrelated to fructose malabsorption. While the protein gluten itself is not an issue for fructose malabsorbers, wheat does contain fructans. Some gluten-containing grains, like oats, which contain gluten due to facility cross-contamination, are safe.
π What is a low FODMAP diet?
The acronym stands for Fermentable Oligo-, Di-, Mono-saccharides And Polyols, and the diet is recommended to IBS sufferers. Saccharide means carbohydrate and the prefixes refer to the number of sugar units β few, two, one β in one molecule of the saccharide. For fructose malabsorbers, the low FODMAP diet is overly restrictive as it advises against dairy products like yogurt, milk, and soft cheese due to the disaccharide lactose.
π§ββοΈ Will my family doctor be familiar with this disorder?
Unlikely, unfortunately. It seems FM is still quite unknown among physicians. However, your experience may vary.
𧬠Is it genetic?
There is anecdotal evidence fructose malabsorption runs in families, often undiagnosed. However, the origin of FM remains unresolved and more research is needed to better understand its causes.
π§ Is fructose malabsorption fructose intolerance?
Fructose intolerance usually refers to Hereditary fructose intolerance, which is a separate condition from fructose malabsorption. HFI is caused by mutations in the gene that codes for the enzyme aldolase B. This enzyme metabolizes fructose in the liver rather than in the small intestine.
β¨οΈ Are there any online communities?
Yes, r/fructosemalabsorption on Reddit, Fructose Malabsorption USA and Fructose Malabsorption Victoria on Facebook. If you join, be a good person, but use critical thinking and watch out for misinformation. Trust but verify.
About the Author
Inspired by the millionth fructose-induced diarrhea, David changed his major to molecular biology during graduate school. Now he is studying absorption and metabolism of fructose to identify the gene or genes that may be responsible for the development of fructose malabsorption.
