Fructose malabsorption is a dietary disability of the small intestine in which the fructose carrier in enterocytes is deficient. Medical tests are similar as in lactose intolerance, requiring a hydrogen breath test for a clinical diagnosis.

Fructose Malabsorption is not to be confused with fructose intolerance or Dietary Fructose Intolerance (DFI), a hereditary condition in which the liver enzymes that break fructose up are deficient. In patients with fructose malabsorption, the small intestine fails to absorb fructose properly. In the large intestine the unabsorbed fructose osmotically reduces the absorption of water and is metabolized by normal colonic bacteria to short chain fatty acids and the gases hydrogen, carbon dioxide and methane. The abnormal increase in hydrogen is detected with the hydrogen breath test.

There is no known cure, but an appropriate diet will help. However, it is very difficult for undiagnosed sufferers to see any relationship between the foods they eat and the symptoms they suffer, even if they keep a daily diet diary. This is because most foods contain a mixture of fructose and glucose. Foods with more fructose than glucose are a problem, as are foods with a lot of fructose (regardless of the amount of glucose). However, depending upon the sufferer's sensitivity to fructose, small amounts of problem foods could be eaten (especially when they are not the main ingredient of a meal).

Foods with a high glucose content actually help sufferers absorb fructose.

Symptoms

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This condition is common in patients with symptoms of irritable bowel syndrome. A small proportion of patients with both fructose malabsorption and lactose intolerance also suffer from coeliac disease.

Typical symptoms of fructose malabsorption include:

• bloating
• diarrhea and / or constipation
• flatulence
• stomach pain (due to muscle spasms, which can vary from mild and chronic to acute but erratic)

Other possible symptoms of fructose malabsorption include:

• aching eyes
• fuzzy head
• fatigue
• depression

Foods with high fructose content

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Foods with a high fructose content include:

• apples
• coconut milk
• fruit juice (especially from apples and pears)
• guavas
• high fructose corn syrup (present in some soft drinks, and used to make sushi rice stick together)
• honey
• lychees
• mangos
• melons
• pawpaws
• pears
• persimmons
• quince

Foods with high fructan content

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Chains of fructose molecules, known as fructans occur naturally in many foods. The following foods have a high fructan content:

• artichokes
• asparagus
• green beans
• leeks
• onions (including spring onion)
• wheat (including most beers, breads, cakes, biscuits, breakfast cereals, pies, pastas, pizzas, and some noodles)

Other problem foods

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In addition, the following foods can cause symtoms of fructose malabsorption:

• dried fruit (including "health" bars containing dried fruit)
• tinned fruit in "natural" juice (which is often pear juice)
• sorbitol (present in some diet drinks and foods, and occurring naturally in some stone fruits)
• sweet wines
• Too much fruit of any kind in a short timeframe

Food labelling laws

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Sufferers of coeliac disease are often protected by food labelling laws, hence processed foods are required to be marked "gluten-free"

However, producers of processed food are not currently required by law to mark foods as "fructose-free". This can cause some surprises and pitfalls for fructose malabsorpers.

Note that foods (such as bread) marked "gluten-free" are usually suitable for fructose malabsorpers, though sufferers need to be careful of gluten-free foods that contain dried fruit or fructose itself in sugar form. However, fructose malabsorpers do not need to avoid gluten as do those with coeliac disease.

Fructose malabsorpers can eat breads and made from rye, spelt and corn flour. However, these may contain wheat unless marked "wheat-free" (or "gluten-free").

See also

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• Gastroenterology
• Invisible disability

References

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• Sugar - Chemical, Biological and Nutritional Aspects of Sucrose. John Yudkin, Jack Edelman and Leslie Hough (1971, 1973). The Butterworth Group. ISBN 0-408-70172-2
• Irrisitibles for the Irritable. A cookbook by accredited dietician Sue Shepherd. Shepherd Works. ISBN 0-9751957-0-0

External links

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• Understanding fructose malabsorption from Metabolic Solutions Inc.
• Fructose intolerance and fructose malabsorption from Foodintol.com
• Fructose- and sorbitol-reduced diet improves mood and gastrointestinal disturbances in fructose malabsorbers Ledochowski M, Widner B, Bair H, Probst T, Fuchs D. Dept. of Clinical Nutrition, Institute of Medical Chemistry and Biochemistry, University of Innsbruck, Austria.
• Fructose Malabsorption Is Associated with Lower Plasma Folic Acid Concentrations in Middle-Aged Subjects technical brief from Maximilian Ledochowski, Florian Überall, Theresia Propst and Dietmar Fuchs.
• Fructose malabsorption is associated with early signs of mental depression Ledochowski M, Sperner-Unterweger B, Widner B, Fuchs D. Dept. of Clinical Nutrition, Institute for Medical Chemistry and Biochemistry, University of Innsbruck, Austria.
• Fructose malabsorption is associated with decreased plasma tryptophan Ledochowski M, Widner B, Murr C, Sperner-Unterweger B, Fuchs D. Dept. of Clinical Nutrition, Institute for Medical Chemistry and Biochemistry, University of Innsbruck, Austria.
• Fructose may cause Irritable Bowel Syndrome by Gabe Mirkin, M.D.
• http://www.nahrungsmittel-intoleranz.com - deutschsprachige webseite

Genetic disorders | Medical terms | Metabolic disorders

Fruktosemalabsorption