Definition: Lactase is the enzyme that helps us digest lactose, which is the sugar in milk and dairy products. Lactose cannot be absorbed by the body unless it is broken down by lactase into glucose and galactose. People who don’t have enough lactase in their intestines can get abdominal cramps, flatulence and diarrhea when they eat milk products.
Lactase is mostly produced in the cells (called enterocytes) of the villi, which line the interior of the small intestine. When the lining of the small intestine is damaged (as happens in untreated celiac disease), lactase production is lowered and lactose intolerance can result.
