Lactose intolerance at a glance
Lactose intolerance is an inability to digest lactose, the main sugar in milk, that gives rise to gastrointestinal symptoms.
Lactose intolerance is caused by a deficiency of the intestinal enzyme lactase that splits lactose into two smaller sugars, glucose and galactose, and allows lactose to be absorbed from the intestine.
The primary symptoms of lactose intolerance are diarrhea, flatulence (passing gas), and abdominal pain. Abdominal bloating, abdominal distention, and nausea also may occur.
Lactose intolerance can be diagnosed by eliminating lactose from the diet, milk challenge, breath test, blood glucose test, stool acidity test, and intestinal biopsy.
Lactose intolerance is treated with dietary changes, supplements of lactase enzyme, and adaptation to increasing amounts of milk.
Avoidance of milk and milk-containing products can lead to a dietary deficiency of calcium and vitamin D that, in turn, can lead to bone disease (osteoporosis