A Perspective on Milk Intolerance

Abstract

Lactose-intolerance is defined as the occurrence of gastrointestinal symptoms after ingestion of a test dose of lactose, usually 50 g in aqueous solution. The amount of lactose in an 8-oz. glass of milk (i.e., that amount normally considered a serving when making dietary recommendations) is only 12 g and is present in a mixture of proteins, fats, salts, vitamins and water. Unfortunately, many people, both in the scientific and health communities, believe lactose-intolerance implies intolerance to milk because of its lactose content. The result has been unwarranted recommendations to reduce or restrict milk consumption for people who may be lactose-intolerant but able to tolerate a normal serving of milk. This may mean an unnecessary loss of milk's important nutrients. Milk has long been recognized as a valuable food in feeding programs directed at overcoming protein-calorie malnutrition and maintaining a nutritionally balanced diet for all people. Milk is a major supplier of three nutrients — calcium, riboflavin and vitamin A — which are commonly found lacking in the American diet. For those people who are truly milk-intolerant, suitable alternatives include cultured dairy products (such as some yogurts), and cheeses, the recommendation to consume smaller quantities of milk more frequently throughout the day, and lactose-hydrolyzed milk. Possible beneficial effects of milk containing bacterial cultures such as Lactobacillus acidophilus also are being studied.