Low intestinal lactase activity - a 40 years perspective

Low intestinal lactase activity (hypolactasia) was discovered in the early 1960s as a cause of lactose intolerance. Since then, it has become clear that hypolactasia in adults is a normal phenomenon in man as in other mammals. Lactase persistence is a dominant autosomal trait, enriched during thousands of years in cattle-raising populations, where continued high capacity to digest lactose might have been related to better health and more children. Hypolactasia is a cause of lactose intolerance, but it should be noted that most people with hypolactasia tolerate considerable amounts of milk products, especially when distributed throughout the day and taken with meals. Perceived intolerance to a few grams of lactose may be due to other food components or related to a general "sensitivity" of the gastrointestinal tract. Keywords: Hypolactasia, lactose intolerance, malabsorption, milk