COW MILK ALLERGY
Key Allergens
There are 12 allergens associated with cows, 9 of them relate to an allergy to the milk they produce (rather than the consumption of meat they produce).
The allergenic proteins in cow's milk are generally split into albumins (commonly called whey) and casein. In human milk the split is usually 60% whey to 40% casein. In cow's milk the split is 20% whey to 80% casein. This massive difference in composition is thought to be the cause of IgE allergic reaction to cow's milk, with most people being allergic to casein proteins in the milk.
Cow's Milk Protein Allergy (also called CMPA) is not be confused with lactose intolerance. A true allergy is to proteins in a food, lactose intolerance is due to a reaction to sugars in milk. Lactose free products should not be used by people with an allergy as they may still contain proteins - always check your labels!
Cross reactivity is usually caused by the proteins in one food being similary shaped to those in another food. Unusually there is cross reactivity between the seed storage proteins in soya beans and the casein in cows milk. This is called non-homologous cross reactivity. This is a common anecdote, that babies allergic to cows milk can often not tolerate soya milk either and this would be the reason.
Cow's milk is usually the first food for many babies, which is why it seems such a common allergy. It is advisable to see your health provider if your baby has an allergy as many very young children with a milk allergy will outgrow it.
The allergenic proteins in cow's milk are generally split into albumins (commonly called whey) and casein. In human milk the split is usually 60% whey to 40% casein. In cow's milk the split is 20% whey to 80% casein. This massive difference in composition is thought to be the cause of IgE allergic reaction to cow's milk, with most people being allergic to casein proteins in the milk.
Cow's Milk Protein Allergy (also called CMPA) is not be confused with lactose intolerance. A true allergy is to proteins in a food, lactose intolerance is due to a reaction to sugars in milk. Lactose free products should not be used by people with an allergy as they may still contain proteins - always check your labels!
Cross reactivity is usually caused by the proteins in one food being similary shaped to those in another food. Unusually there is cross reactivity between the seed storage proteins in soya beans and the casein in cows milk. This is called non-homologous cross reactivity. This is a common anecdote, that babies allergic to cows milk can often not tolerate soya milk either and this would be the reason.
Cow's milk is usually the first food for many babies, which is why it seems such a common allergy. It is advisable to see your health provider if your baby has an allergy as many very young children with a milk allergy will outgrow it.
Associated Syndromes
Cow's milk allergy is not currently associated with any allergic syndromes.
Cross Reactivity
There is a lot of evidence of cross reactivity between cow's milk and eggs and this is due to serum albumin proteins found in both.
About 13 - 20% of cow's milk allergy sufferers will also react to beef when consumed. This is, again, due to serum albumin proteins found in both foods.
Cow's milk allergy has also been linked to a soya allergy - the soya protein component that cross-reacts with casein has been identified as a glycinin molecule.
About 13 - 20% of cow's milk allergy sufferers will also react to beef when consumed. This is, again, due to serum albumin proteins found in both foods.
Cow's milk allergy has also been linked to a soya allergy - the soya protein component that cross-reacts with casein has been identified as a glycinin molecule.
Resources
Websites
Allergen Encyclopedia - Cow's Milk
Allergy information for: Milk, cow (Bos taurus)
Allergy UK - Cow's Milk Allergy
Anaphylaxis Campaign - Milk Allergy
Articles and Journals
Long-term Outcomes of Children with Cow’s Milk Protein Allergy in a Pediatric Allergy Clinic, 2021
The effect of a cow’s milk-free diet on asthma control in children: a quasi-experimental study, 2021
Cross-reactivities of non-homologous allergens, 2019
The natural history of milk allergy in an observational cohort, 2013
Anaphylaxis to cow's milk and beef meat proteins, 2002
Gastroesophageal reflux and cow's milk allergy in infants: A prospective study, 1996
Allergen-specific IgE antibodies against antigenic components in cow milk and milk substitutes, 1986
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