Until I got tested for it, I never knew fructose malabsorption even existed. However, it did explain why I could never really pin point why some foods worked well with me sometimes and not others. In fact, it explained a lot of my digestive troubles.
What is it?
Fructose malabsorption should not be confused with fructose intolerance, which is a much more serious disease. Basically, when fructose hits your small intestine, it uses what are called GLUT5 transporters to get distributed to your blood stream before being metabolized by your liver so that it can be used by your organs. Someone with fructose malabsorption does not have enough of these transporters, so the fructose never gets properly digested, it ferments and bacteria feeds off it and this can lead to gas, bloating, diarrhea and a host of other digestive symptoms. Symptoms vary depending on the person and some can tolerate more fructose than others. You can consume fructose but it needs to be limited. Studies have shown that over 30% of the population have this condition and that it is a lot more prevalant than lactose intolerance.
What foods have fructose?
Fructose can be found in fruits, honey and basically any condiment or product that uses corn or fructose syrup. Some fruits have an equal amount or more of glucose than fructose – in these cases, they can use other transporters than GLUT5, which means the fructose can get digested. For example, berries have more glucose than fructose so they are ok to eat.
Fructans, a form of fructose, can also be found in vegetables and wheat. To me, this was the hardest thing to cut down on and it turns out fructans is what I react the most violently to.
What causes it?
There is a lot of speculation as to what causes FM. The expression of GLUT5 is apparently significantly affected by diabetes, hypertension, obesity, and overall inflammation in the body. It is also more common among women, however, it has not yet been determined what the root cause is.
How to test
The most accurate way of testing it is to take a hyrdogen breath test whereby you ingest fructose and a sample of your breath is taken every 20 minutes to measure hydrogen levels. It takes around 2 hours. Here in Dubai, a good gastroenterologist should be able to conduct this test. I got mine done at the Health Bay Polyclinic in Umm Suqeim. I was also very well advised by a nutritionist called Stephanie Karl here in Dubai.
How to treat
The most common way to manage fructose malasborption is to follow the Low FODMAP diet, a nutritional regime that eliminates Fermentable Olygosaccharides, Disaccharides, Monosaccharides And Polyols. It is quite restrictive in some ways but like I said earlier, you can have tiny quantities of these foods. Also, it encourages you to eat whole foods and forces you to look at the ingredients of what you put in your mouth. Since I’ve been doing this, not only have I become a lot more informed but my bloating has gone way down and I don’t remember feeling this good in my adult life.
Over time, you can start re-introducing a few foods to understand how sensitive you are to them because everyone is different when it comes this. Some may react very badly to certain fruits, whereas others just can’t stomach broccoli, beans or specific food additives.
The Monash University in Australia have done a lot of studies on this and offer an app you can use as a guide to the Low FODMAP diet. There is also a Dr Kate Scarlata, who has a lot of great resources on her website.
Keep mind though that if you have had fructose malabsorption for a long time, you likely have an imbalance in terms of your gut bacteria so it is wise to run tests and understand if you have developed other issues as a result. For example, you could also have a case of yeast overgrowth or even parasites. The best thing is to get tested for these to make sure you really get a big picture of where your digestive health is at.
