laktoseintolerance

Laktoseintolerance is the common term for the inability to digest lactose, the main sugar in milk, due to reduced activity of the intestinal enzyme lactase. When lactose remains undigested, it passes into the colon where bacteria ferment it, producing gas and osmotic effects that can cause abdominal discomfort and altered bowel movements.

There are several forms: primary lactase deficiency (lactase non-persistence) that typically becomes apparent in adolescence or adulthood; secondary lactase deficiency caused by injury or disease of the small intestine (for example celiac disease, gastroenteritis, inflammatory bowel disease); congenital lactase deficiency present from birth; and rare developmental forms.

Symptoms include abdominal pain, bloating, excessive gas, diarrhea, nausea, and sometimes vomiting after consuming lactose-containing foods. The severity depends on the amount of lactose consumed and the level of lactase activity in the gut.

Diagnosis is clinical and may be confirmed with tests such as the lactose hydrogen breath test, a lactose tolerance test, or genetic testing for lactase persistence. An elimination and reintroduction diet can help determine an individual’s tolerance.

Management centers on dietary modification. Most people can reduce symptoms by limiting lactose-containing foods or using lactose-free dairy products. Lactase enzyme supplements taken with dairy can also help. It is important to maintain adequate calcium and vitamin D intake from non-dairy sources if dairy is restricted.

Epidemiology varies by ethnicity and region. Lactase non-persistence is common in many parts of Asia and Africa, less common among people of Northern European descent. The condition is not dangerous by itself, but persistent symptoms can affect quality of life and nutritional balance if dairy is a major food source.