I can't tell you how often parents present the following scenario in my office:
"Dr. Samson, I'm so frustrated because you told me that my child is allergic to cow's milk. I put him on lactose free milk and he still has cramps, diarrhea, nasal congestion and coughing. I don't give him any other dairy products but he is still sick all the time. Are you sure that your diagnosis is correct? What can I do?"
The common misconception that lactose free milk helps those people with milk allergy needs to come to an end. Even though an article on this subject has been published many times the concept continues. Let's review the difference between the two problems. 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. 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 that 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 LACTAID. This is essentially 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. Basically LACTAID has no place in the management of true cow's milk allergy patients.