I worry about allergies. We have a lot of allergies in our family and I’m concerned that my child may develop milk allergies. How common are these and how do I recognize them? Milk allergies are over-diagnosed by the general population and under-diagnosed by doctors. The real incidence of milk allergies lies somewhere between the folklore and the skeptical view of many physicians. Around five percent of children and adults seem to be either allergic to milk or intolerant of it. One carefully controlled study showed that 75 percent of infants under one year of age were allergic to cow’s milk. Cow’s milk allergy is more likely to develop in children who have a family history of milk allergy. The good news is that of the approximately two percent of children who are truly allergic to milk, many will outgrow this allergy by the time they are two or three-years-old.
The protein in cow’s milk is what provokes the allergies. Because milk is a species-specific protein, cow’s milk is suited to bovine intestines. Exposure of human intestines to bovine protein may cause irritation and damage to the intestinal lining, allowing these allergenic proteins to be absorbed into the circulatory system. The immune system recognizes these proteins as foreign and attacks them, causing the usual allergy symptoms of wheezing, runny nose, or a red, rough, sandpaper-like rash, especially on the cheeks. Milk allergies are often the underlying cause of repeated colds and ear infections, due to fluid building up in the respiratory passages, sinuses, and eustachian tubes of the ears. Milk allergy has been implicated in subtle behavioral changes, such as irritability and nightwaking. Research has even shown that the allergic proteins in milk (beta lactalglobulin) can pass through a breastfeeding mother’s milk into her baby and cause some babies to react with colicky symptoms. The colic- cow’s milk connection should be suspected as a possible cause of fussy behavior in an otherwise, normal breastfed baby. The allergic reaction between the milk protein and the intestinal lining can cause minute gastrointestinal bleeding (sometimes so slight that it is missed) and be a subtle cause of anemia in infants and young children.
Chronic milk allergy can also weaken the intestinal lining, allowing foreign substances into the bloodstream that would ordinarily be screened out, a condition known as the leaky gut syndrome.
Since true milk allergy involves the protein in the milk, the fat content of the milk should not affect allergy symptoms. People who are allergic to milk may be able to tolerate cheese or yogurt, or milk in baked goods. When milk is heated, the proteins become less allergenic.