Lactose intolerance

Lactose intolerance is the inability of adults and children to digest lactose, a sugar found in milk and to a lesser extent dairy products, causing side effects. It is due to a lactase deficiency, or hypolactasia. In some (rare) cases, individuals have congenital alactasia, a total absence of lactase caused by a genetic defect, which prevents them from being able to digest lactose from infancy.