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Cow’s milk protein allergy (CMPA)

Posted On: April 12, 2021 By Elzette Struwig
12 Apr

Cow’s milk protein allergy (CMPA) and the lactating mother by Elzette Struwig RD(SA)

An allergy is an immune-mediated response.

A food allergy occurs when the immune system identifies a food protein as hazardous, which causes the immune system to become activated. This is to protect the body from this protein. Symptoms that range from asthma, eczema, rashes, rhinitis, or even anaphylaxis can then occur. Regarding food allergies, IgE-mediated Cow’s milk protein allergy (CMPA) is the most common allergy in infants during the first year of life [1].

Cow’s milk protein allergy (CMPA) can often manifest in a breastfed or formula-fed infant through delayed reactions, such as vomiting, diarrhea, colic, and intestinal constipation [2]. The diagnosis of CMPA is based on the improvement of symptoms on the exclusion of cow’s milk protein (CMP) from the diet or IgE blood tests, which can be very traumatizing for the infant [2]. The treatment option is the exclusion of the allergen from the diet. In a breastfeeding mother, the milk protein is transferred from the mother’s bloodstream, due to intake from her diet, to the breastmilk. A breastfeeding mother may and ideally should continue breastfeeding her infant with CMPA. A mother who makes this decision, for the benefit of her child, should then exclude CMP from her diet. Cow’s milk elimination (in a child who is no longer being breastfed) without adequate replacement feed may impair the normal growth and development of the child [2]. Please keep in mind that this allergy is not related to lactose (the sugar found in dairy products), but whey and casein, the protein found in dairy products. In this case, lactose-free products would make no difference. Unfortunately, whey (the CMPA seen more often), is found in an even greater variety of food products than lactose. For example, whey is often used as a seasoning in food sources such as chips, sauces, and baked goods.

A lactating mother of an infant with CMPA should exclude all the allergens from her own diet. This can be done by proper label reading. Or better yet, to avoid products contained in packages and wrapping and rather stick to natural options such as fruit, vegetables, meat, fish, eggs, and foods high in fatty acids such as nuts, seeds, avocado, and oils. 

Once the infant’s symptoms start to improve, it is a confirmation that the CMPA was the cause for the little one’s discomfort. It is recommended to reintroduce an allergen with the supervision of a dietitian. The reintroduction of an allergen is called a food challenge and it is to determine whether the infant has outgrown the allergy. Ideally, a mother should first start using cow’s milk protein products again, before providing it directly to her infant.

The mother and infant need to maintain a well-balanced dietary intake while excluding cow’s milk protein from the diet. A dietitian can help to establish these requirements and assist with the reintroduction of the allergen.


  1. Perezabad L, López-Abente J, Alonso-Lebrero E, Seoane E, Pion M, Correa-Rocha R. The establishment of cow’s milk protein allergy in infants is related with a deficit of regulatory T cells (Treg) and vitamin D. Pediatric Research. 2017: 5 (81); 722.
  2. Faria D, Cortez A, Speridião P, Morais M. Knowledge and practice of pediatricians and nutritionists regarding the treatment of cow’s milk protein allergy in infants. Rev. Nutr. 2018;31(6):535-546.
Elzette Struwig
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