Pages Menu

Column originally published May 17, 2011

Breastfeeding Can Prevent Cows Milk Protein Allergy

Question: Our son is two years old. I put him on formula after he was born. A few weeks later he started vomiting and then passed blood in his stool. His skin also broke out with a rash. We were referred to a paediatrician who diagnosed him with cows milk allergy. He gradually got better on soy formula. In the last few months, when we give him homogenized milk, he would complain of belly pain and become congested. Our family doctor suggested that he may be developing asthma. I wonder whether this may be related to his cows milk allergy. Now I am pregnant with our second child, I wonder what I can do to prevent the same problem from happening to this baby.


From your description, your son likely has significant cows milk allergy. He is allergic to the protein in the cows milk. This is not an uncommon problem at all. The trouble is that it doesnʼt happen right away when a baby is started on cows milk formula after birth. It usually takes several weeks before the symptoms become obvious, and by that time it is too late to consider breast feeding.

As you have experienced, the most common symptoms of cows milk allergy are vomiting, diarrhea, presence of blood in the stool, and skin rashes that are called eczema. There are less common, but potentially more dangerous problems like losing protein in the intestines, as well as asthma.

Most of the time, cows milk allergy symptoms improve after the baby is put on non-cows milk formula. The most common and commercially available ones are soy formula. They are just as safe as cows milk formula, and they are produced under the same kind of strict guideline set out by the government. Unfortunately, about ten percent of those babies who are allergic to cows milk can also become allergic to soy formula. It is not possible to predict which child will react to soy. This is really a trial and error situation. Other alternatives include goats milk and highly digested cows milk formula. Goats milk formula is often available in supermarkets and pharmacies. Goats milk is deficient in a vitamin called folic acid, but goats milk formula is supplemented with this vitamin already. Highly digested cows milk formula are very expensive, and usually not recommended unless a baby is allergic to other less expensive choices.

Occasionally, asthma-like symptoms can occur in children with cows milk allergy. They become congested even without any cold symptoms. If a child has other symptoms of cows milk allergy and has chest congestion, it is worthwhile to avoid cows milk for several weeks to see whether the symptoms improve. Since your son is already two years old, you can give him soy milk from supermarket. Sometimes it is necessary to read labels of other processed foods because cows milk protein (whey or casein) is often added to them to increase their protein content.

I am glad that you are looking ahead to see how you can prevent your next child from going through the same problem. Since allergy is a genetic condition that is passed from generation to generation through the parentsʼ genes, your second child may be allergic to cows milk also. There is no definitive research to recommend whether you should avoid cows milk during pregnancy or not. There may be some potential benefit from the allergy standpoint, but you have to make sure that you get enough calcium and vitamin D from other sources, including vitamins.

The best way to prevent your next baby from cows milk allergy is to breastfeed him or her right after birth. Since you did not breastfeed your first boy, you have to learn to do that. Many maternity nurses have training and are very supportive of breastfeeding mothers. There can be challenges but most women can breastfeed effectively if they stick to it. Most breastfeeding babies need to be nursed more frequently than bottle-fed babies because breast milk is natural and easy to digest, so babies end up getting hungry sooner. Formula, on the other hand, are harder for babies to digest, and they stay in the stomach for longer, so that these babies need feeding less frequently. As you can see in your sonʼs situation, he got into other troubles that could have been prevented by breastfeeding.

Once in a while, a breastfed baby can still develop cows milk allergy. This happens when the mother is consuming dairy products like cows milk or cheese. Those babies that develop cows milk allergy through the motherʼs breast milk are likely very allergic babies. In that situation, we have recommended mothers to stop all dairy products while nursing. Once again, you need to make sure that you are consuming enough calcium and vitamin D from other sources.

There is some new research suggesting that highly allergic children have a higher chance of developing wheat allergy if they are given wheat much later than 6 months of age. This information is still regarded as preliminary, more definitive research is cur- rently being done. Therefore, it may be advisable for you to start your next baby on wheat-based cereal between 4 to six months of age.

I hope this information is useful for you as well as many mothers out there who have children with cows milk allergy. One needs to remember that cows milk were made for cows. We borrowed them for our use. Motherʼs breast milk is most suitable for our babies. Women should try to breastfeed if at all possible.