Fructose Malabsorption: Testing,Treatment & Diet
Is it the cause of your stomach troubles?
You may have never heard of it, but fructose malabsorption may be causing your stomach problems.
What Is Fructose?
Fructose is a sugar that is found in many foods such as fresh fruits and honey, high fructose corn syrup, and many processed foods. It is also a component of plain table sugar, and some vegetables.
Some people cannot completely absorb fructose in their small intestine-the beginning part of the digestive tract. The undigested fructose is then carried to the colon where our normal bacteria rapidly devour it. In the process, the bacteria produce gases which cause the intestine to swell. This is experienced by the person as bloating, cramping, gas, and distention. Diarrhea may also occur due to the undigested particles of fructose.
This is also known as hereditary fructose intolerance. It is VERY different from fructose malabsorption and we will not cover it here except to say the following: it occurs in infants, is hereditary, and can lead to severe health problems such as liver disease, seizures, and mental retardation. The names are similar but the entities are VERY different. There is some confusion in that fructose malabsorption is at times referred to as DIETARY fructose intolerance. We are discussing FRUCTOSE MALABSORPTION.
Mimics Other Digestive Problems
The symptoms of other disorders such as celiac disease and non-celiac gluten sensitivity (NCGS) can be very similar to the symptoms of fructose malabsorption. Thus, the diagnoses’ may often be confused or difficult to make. Fructose malabsorption can also mimic lactose/milk intolerance, IBS, SIBO, IBD, FODMAP intolerance and more. Fructose malabsorption (FM) may also be seen with celiac disease or NCGS and should be considered in these patients who are already on a gluten-free diet, yet have ongoing symptoms. It needs to be thought of intentionally or it is easy to miss.
Symptoms Of Fructose Malabsorption
The onset of symptoms can occur at any age. Symptoms vary depending on the person and the amount of fructose they have eaten. Some people can tolerate much more fructose than others. The most common symptoms are bloating, gas, cramping, and diarrhea. When diarrhea occurs over prolonged periods, nutrient deficiencies and their symptoms may appear. The most common nutrients affected are folic acid, zinc, iron, tryptophan, calcium, vitamin c, and e. Elevated blood levels of amylase and lipase enzymes from the pancreas- may also be seen. Some people may also experience symptoms such as fatigue, headaches, brain fog, mood changes, and constipation.
Testing For Fructose Malabsorption
The standard test done to evaluate for fructose malabsorption is called a Fructose Malabsorption Breath Test. This is a simple test, that can be done in the office and requires no blood be drawn. Some patients choose to start with a fructose elimination diet in lieu of the breath test. This is best done in conjunction with a dietitian familiar with fructose malabsorption to assure the diet is initiated properly and adequate nutrition is maintained during the elimination period. If fructose malabsorption is the problem and the diet done correctly, it often yields good results. If the elimination diet does not yield clear results and fructose malabsorption is still a consideration, the breath test should be performed.
Treatment: Low Fructose Diet
The treatment for fructose malabsorption is a low fructose diet. This is a diet that limits foods containing high amounts of fructose or with a significant amount of fructans. Fructans are a form of fructose found in wheat and vegetables.
Some examples of high fructose foods include fruit, sweeteners including honey, juices, high fructose corn syrup and corn syrup solids
A complete LOW FRUCTOSE DIET HANDOUT is found here,
Does A Low FODMAP Diet Help?
The Low FODMAP diet is most commonly used for IBS and SIBO but also for other digestive disorders such as inflammatory bowel disease. The low FODMAP diet does eliminate fructose but it also eliminates other sugars/carbohydrates. It is much more restrictive than the low fructose diet. It will help fructose malabsorption but it typically is more limiting than a person with fructose malabsorption needs.
FODMAP stands for “ Fermentable, oligo-di and monosaccharides and polyols”. A low FODMAP diet eliminates:
- Lactose-the milk found in cow, sheep and goat milk
- Fructans-as mentioned above. A form of fructose found in wheat and vegetables. The most common vegetables are onions and garlic. Other common fructans are inulin and fructooligosaccharides (FOS). These are found in many probiotics and “nutrient fortified” foods.
- Galactans– a carbohydrate found in beans and lentils
- Polyols– A sugar alcohol. The most common are the artificial sweeteners sorbitol, xylitol and mannitol.
Permanent Or Temporary?
Everyone has a different tolerance level to fructose. If you have fructose malabsorption, it is recommended to eliminate fructose for 4-6wks. and then re-introduce fructose-containing foods one at a time every four days. Each individual will find their own tolerance level for dietary fructose. If your symptoms have subsided on a low fructose diet and they return upon reintroduction of food. You have found your sweet spot! The best news is you may have also found the answer to your digestive woes!
THIS ARTICLE IS COPYRIGHTED BY AMY BURKHART, MD, RD.
Dr. Amy Burkhart is a doctor (M.D.), Registered Dietitian, R.D., and fellowship-trained in integrative medicine. She specializes in treating chronic digestive disorders from an integrative/functional medicine perspective.