As taken from the Pediatric Medical Center ALLERY HANDBOOK.
Question: My 18-month-old son did fine on Similac formula but when I switched to regular milk at nine months of age he began having chronic congestion. I then took him off milk and he was put on calcium supplement and non-milk liquids, after which he remained clear. He now can eat “hard” processed cheese without problems but still gets nasal congestion when he drinks milk. Since Similac is a cow’s milk formula and cheese comes from milk, how can he tolerate them and not milk?
Answer: I suspect we have all known people who can eat cheese yet not drink milk or eat ice cream without getting symptoms. On the surface it seems contradictory but as you read on you will see it is reasonable.
Cow’s milk basically has five protein fractions: Beta-lacto-globulin, Casein, lactalbumin, bovine serum albumin and bovine gamma globulin. All are present in untreated milk but as milk is subjected to manufacturing processes some are destroyed. Heat is the primary way the proteins are altered. These five proteins can be divided into three groups according to their response to increased temperature. Casein is the most heat stable; it can withstand 120 degrees C for 15 minutes. Beta-lacto-globulin and lactalbumin are relatively heat stable in that they can withstand 100 degree C for 15 minutes. The least stable are bovine serum albumin and globulin. These two are destroyed when exposed to 80 degree C for 15 minutes.
Medical researchers vary in their opinions on which fractions are most allergenic. This concept is not critical since each patient is an individual and we must pattern the diet for a particular child.
It is important to know what ”dairy products” contain which protein fractions. Since a given patient may only be sensitive to one of the fractions certain “dairy products” may be available for the child to consume. Unfortunately, some patients are sensitive to all five fractions and thus must be kept away from all milk products. Raw milk, pasteurized milk, yogurt, cottage cheese, ice cream and sherbet contain all five fractions. Evaporated milk, infant formula, powdered milk and “hard” processed cheese are free of bovine serum albumin and globulin, but do contain the other three proteins. The answer to your question now becomes obvious. Assuming your observations are correct, your son would seem to be sensitive to either or both of the bovine serum proteins. As you can see infant formula and cheese are free of those two proteins. Also, your son may be able to tolerate evaporated milk and powdered milk. I have patients who exactly fit into your son’s situation. They can drink low-fat powdered milk and eat processed cheese without a problem. But a teaspoon of pasteurized milk or ice cream and symptoms present themselves. I must say that the majority of cow’s milk protein sensitive children are sensitive to more than the two heat labile fractions and thus can not tolerate powdered milk or cheese.
The importance of identifying these patients is clear. It is much more convenient and less costly to be able to give a patient cheese and powdered milk than to have to restrict all milk products from their diet. Any parent of a milk allergy patient can attest to that.
A work of caution: if anyone reading this column feels his “milk allergy” child may not be sensitive to all protein fractions, consult your physician before trying the products free of the heat labile proteins. Furthermore, a trial must be done very cautiously and under medical direction.