Lactose Sensitivity—A Large Problem

     Lactose (milk sugar) is the principal carbohydrate of milk and often causes symptoms ranging from mild to serious, mainly gastrointestinal, in a large percentage of persons who use dairy products.  When a patient has vague gastrointestinal complaints, it is always necessary to think of lactose intolerance.  Lactase is an enzyme that helps in the digestion of lactose, and if there is incomplete digestion of milk, irritation can result, or the formation of gas or acids.

     Thirty-three million Americans have low lactase levels.  There is a normal, post-weaning reduction in lactase activity in all mammals.  If lactose cannot be digested because of insufficient lactase, the un-split lactose passes into the colon where fermentation produces gas, alcohols, and irritating organic acids such as lactic and acetic acids.  There is a great likelihood that intestinal production of the enzyme lactase is absent or low in persons with digestive complaints at all ages.  An acid stool with a pH of less than six is significant in making the diagnosis of lactase insufficiency.  Patient Care   February 15, 1976


     Many persons with misdiagnosed lactose intolerance have been said to have functional bowel disease, nervous or ulcerative colitis, spastic, neurotic, or irritable bowel syndrome.  These persons suffer from diarrhea, nausea, cramps, vomiting and abdominal pain.  Some degree of lactose intolerance is present in almost 100% of adult Africans, Orientals, and American Indians, and 60-70% of descendants of Ashkenazi Jews, Black Americans, and Mexican Americans.  Ten to fifteen percent of white Americans, of Scandinavian or northern European descent are lactose intolerant.  Forty percent of United States black elementary students and 75% of black teenagers are intolerant to milk.  Approximately 80% of the world’s population does not produce sufficient lactase, and consequently cannot completely split the lactose present in any reasonable serving of dairy products.  In these low lactase producers, symptoms are common.  Most infants with demonstrated lactose intolerance will have a complete relief  of abdominal pain upon withdrawing milk and milk products from the diet.

     In many parts of China, the use of milk and eggs is thought of with disgust and aversion, much as Americans regard with disgust the use of blood as food or beverage.  Many Chinese develop abdominal discomfort after drinking milk due to an inability to metabolize lactose.  Lactose intolerance producing aversion to milk may be one physiological mechanism in the development of culturally determined attitudes toward food.  An easy way to make the diagnosis of lactose intolerance is by stopping the mik intake for about a week, then giving two glasses of cold milk (which produces symptoms more readily than warm milk).  It can thereby be easily determined if there is a relationship between milk drinking and the physical complaints.  Hospital Practice  October 1976


     The mandatory milk distribution programs in school lunch rooms are not only not beneficial, but are probably harmful to most non-Caucasians.  Elevated temperatures, vomiting, or diarrhea with weight loss are signs of lactose sensitivity, along with a multiplicity of other symptoms related to the abdomen or to other systems.  Lactase deficiency may lead to the development of cataracts since the improper digestion of milk can allow certain parts of the milk, notably galactose, to accumulate, and cataracts are more common when galactose is high in the diet.

A. & C. Thrash