Is lactose intolerance a disease?
Dr. Paige: You need to distinguish between lactose intolerance that may occur secondarily to an intestinal insult in an infant and the mechanism that occurs in normal healthy older children and adults. Here in the United States, where so many are of western European extraction, we think of lactose intolerance almost as though it were a disease. But if you look at the mammalian world as a whole, although both human and animal babies drink mother’s milk for a time, after infancy mammals usually lose the ability to digest lactose, and they go on to other foods. So-called lactose intolerance is the normal state of affairs in adults. But all baby mammals start out as “lactose-tolerant.” One of the defining criteria for being a mammal, after all, is that as an infant it drinks mother’s milk. True milk allergy to human milk or formula occurs in only 1 percent to 8 percent of all babies and is not related to lactose intolerance.
