Fructose Intolerance and Fructose Malabsorption

Hereditary fructose intolerance is an inherited disease characterized by a congenital enzyme deficiency of fructose-1-phosphate aldolase. Its frequency of occurrence is 1:20,000 - 1:130,000 (depending on the source) and causes liver damage, kidney damage and hypoglycemia. In this case fructose is absorbed by a transport system in the bowel, but it cannot be properly degraded in the liver.

Intestinal fructose intolerance (fructose malabsorption, fructose hypersensitivity), by contrast, is an acquired disorder caused by a defective transport system in the small intestine, i. e. fructose is not absorbed sufficiently by the body. Yet once it has made its way into the body, it is easily degraded.

Public usage of the term “fructose intolerance” refers almost exclusively to intestinal fructose intolerance or fructose malabsorption.

How much fructose can be found in food?

  • Honey: 38.8 g/100 g
    equals 5.8 g per portion (portion size 15 g)
  • Strawberry jam: 18.8 g/100 g
    equals 2.8 g per portion (portion size 15 g)
  • Apple sauce: 7.5 g/100 g
    equals 11.3 g per portion (portion size 150 g)
  • Apple: 5.7 g/100 g
    equals 8.6 g/100 g per portion (portion size 150 g)
  • Orange juice: 2.5 g/100 g
    equals 6.4 g per portion (portion size 250 ml)
  • Tomato: 1.4 g/100 g
    equals 1.4 g per portion (portion size 100 g)
  • Carrot: 1.6 g/100 g
    equals 1.3 g per portion (portion size 80 g)

Source: Souci/Fachmann/Kraut "Food Composition and Nutrition Tables", 7th revised and completed edition (April 1st, 2008), Wissenschaftliche Verlagsgesellschaft mbH, Stuttgart