Lactose intolerance is the inability to metabolize lactose, a sugar found in milk and other dairy products, because the required enzyme lactase is absent in the intestinal system or its availability is lowered. It is estimated that 75% of adults worldwide show some decrease in lactase activity during adulthood.[1] The frequency of decreased lactase activity ranges from as little as 5% in northern Europe, up to 71% for Sicily, to more than 90% in some African and Asian countries.[2]
Contents
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* 1 Classification
* 2 Lactase biology
o 2.1 Lactose intolerance by group
* 3 Diagnosis
o 3.1 Hydrogen breath test
o 3.2 Stool acidity test
o 3.3 Intestinal biopsy
o 3.4 History of diagnosis
o 3.5 Nomenclature
* 4 History of genetic prevalence
* 5 Managing lactose intolerance
o 5.1 Avoiding lactose-containing products
+ 5.1.1 Dairy products
+ 5.1.2 Lactose in non-dairy products
+ 5.1.3 Alternative products
o 5.2 Lactase supplementation
o 5.3 Rehabituation to dairy products
* 6 Nutritional concerns
o 6.1 Primary lactose intolerance
o 6.2 Secondary lactose intolerance
o 6.3 Congenital lactase deficiency
* 7 See also
* 8 References
o 8.1 Bibliography
o 8.2 Notes
* 9 External links