Question: My two-year-old son gets a runny nose and cough whenever he drinks whole or low fat milk. Several weeks ago my neighbor told me to use LACTAID because it was good for people who couldn’t tolerate regular milk. She said it was treated with an enzyme that changed it. I took her advice and he gets the runny nose and cough whenever he drinks it. Why doesn’t it work, or is my son not allergic to milk?
Answer: Your neighbor shares a very common misconception with many people. Frequently the condition of cow’s milk protein allergy and lactose intolerance are confused.
Cow’s milk contains specific proteins as well as the carbohydrate, lactose (milk sugar). A patient who is allergic to milk is reacting to the protein in it. That is, he has made specific antibodies to the bovine protein. The reaction between the antibody and the protein causes release of substances from the various body cells which provoke the symptoms of allergy. Depending on the individual patient the symptoms can range from nasal discharge and cough to diarrhea, vomiting, rashes and behavior changes.
A child who has an intolerance to lactose may develop diarrhea, cramps, abdominal distension and even vomiting whenever he ingests dairy products. Respiratory symptoms are not provoked by this condition.
The problems come from a lack of an enzyme lactase produced by the intestine. The enzyme is needed to break down lactose to the absorbable molecules of glucose and galactose. Thus, if lactase activity is insufficient the undigested lactose remains in the bowel leading to the symptoms described above.
Keeping these two conditions in mind let us look at the product you mentioned. LACTAID essentially is cow’s milk treated with lactase, which causes the breakdown of lactose. Unfortunately it is not completely changed. The manufacturers state that 70% of the lactose is turned into its digestible fractions. The remaining 30%, in some patients, may still cause symptoms. Nevertheless, for some lactose intolerant patients it can be a very helpful product.
The allergic patient is reacting to the protein, and thus, altering the carbohydrate fraction will not help prevent allergic reactions. We must remember that the cow protein is not altered in LACTAID.
To specifically answer your questions it certainly sounds like your son is allergic to cow’s milk. Furthermore, I think you can see why LACTAID did not help him. Basically LACTAID has no place in the management of true cow’s milk allergy.