Lactose intolerance in the adolescent

Abstract

What do Oriental adults, some American blacks, Eskimos, American Indians, American Jews, and some adolescents with abdominal pain have in common? The answer is lactose intolerance. An individual with lactose intolerance is unable to adequately digest a large lactose load equivalent to one or two quarts of milk. Approximately half of such lactose intolerant adults will have recognized that one or two glasses of milk will cause bloating, flatulence or a laxative effect (1). In these otherwise healthy adolescents and adults, this carbohydrate digestion problem is due to a postinfancy fall in intestinal lactase levels which is inherited as an autosomal recessive trait. Adults with isolated low lactase levels comprise over 90% of many populations including Orientals, Australian Aborigines, Peruvian Indians, American Indians, and certain Nigerian tribes believed to be the ancestors of many American Blacks. The prevalence of lactose intolerance is 70% in American blacks, 60% in American Jews and Mexican-Alnericans, and 10-15% in the U.S. white population who are of northwestern European or Scandinavian extraction (2). These otherwise healthy' people, who could drink large quantities of milk as children, are apparently genetically programed to have low intestinal lactase levels and to become milk: intolerant as adults. Do they first become aware of milk intolerance during teenage? Is lactose intolerance a factor in some teenagers with recurrent abdominal pain? Is this something to be considered in such patients? How can one test for lactose maldigestion in the adolescent? Is milk the appropriate protein-calcium source for all teenagers with special nutritional needs, such as pregnancy or illness? These are some of the ques-