Cow's milk allergy and cow's milk intolerance are often used interchangeably, resulting in confusion in clinical practice and public understanding. Cow's milk intolerance refers to non-allergic, non-immunological reactions to cow's milk such as disorders of digestion, absorption or metabolism of certain cow's milk components. It is generally a benign condition with mild, nonspecific and highly individual symptoms limited to the gastrointestinal tract (diarrhoea, bloating and distension, flatulence and abdominal pain). The severity of symptoms varies with the amount of lactose; conditions under which lactose is consumed; and the ability to tolerate the lactose load. Congenital lactase deficiency in infants is a rare condition. A primary lactase deficiency is the most common cause of cow's milk intolerance, affecting all age groups and may be life-long. Clinical manifestations usually only become evident at puberty or late adolescence. In contrast, a secondary lactase deficiency is a transient condition which develops secondary to bacterial or viral infection. Diagnosis of lactase deficiency is made on the basis of a history of gastrointestinal symptoms, occurring after and aggravated by milk ingestion; response to an empiric trial of dietary lactose reduction or avoidance; a breath test demonstrating abnormal hydrogen levels; an abnormal lactose tolerance test; stool sample for reducing substances or acidic pH; and/or small intestinal biopsy to assess direct lactase enzyme activity Symptoms are alleviated by complete elimination or reduced consumption of lactose-containing foods. Most lactose intolerant adults, however, can consume some lactose without major symptoms, thereby reducing the need for strict elimination of dairy (excellent source of calcium, phosphorous, magnesium, vitamin A, riboflavin and protein). The literature is explored on how much is needed to cause actual clinical symptoms. Controversial associations regarding the role of lactose intolerance in irritable bowel syndrome, infant colic and inflammatory bowel disease are discussed as well as the possible beneficial role in reducing the incidence of 'developed society' large bowel diseases in the black African population. Public awareness and misunderstanding of lactose intolerance are at an all time high. Health professionals need to alleviate patients' fears about lactose intolerance, discuss the importance of calcium-richfoods and recommend dietary strategies to improve lactose tolerance only when intolerance is clinically proven. With the help of a qualified dietitian, individual lactose tolerance threshold levels can be determined to adjust the amount of lactose that can be consumed comfortably at any one time. Strategies are discussed to ensure this inclusion of milk and other dairy products without implementing strict elimination diets.
