Allergy to cow’s milk has increased in the last few years. Researchers suggest that both genetics and environmental risk factors are germane to the development of this allergy which may precede the allergic march.
A study in Allergy noted a strong connection between the birth method of delivery and milk allergy. Children who are born through Caesarean section (CS)are twice as likely to develop a milk allergy or intolerance than other children. Dr Eggsboe and colleagues studied 2656 children in the Oslo Birth Cohort and found that a cow’s milk allergy or intolerance was twice as common in children delivered by CS as compared with children delivered vaginally.
Children who had been diagnosed with a milk allergy or intolerance but who became tolerant by the age of 2 years and 6 months were not delivered by CS, thus suggesting a negative association between CS and tolerance. There is an association between CS and persistent milk allergy.
The study concluded that a predisposition to allergy did not influence the results and that early intestinal colonization may play a major role in the etiology of food allergy. Intestinal microflora in children, related to the method of delivery may be associated with subsequent development of allergic disease. In effect, CS does not increase the overall risk of food allergy but rather increases the risk of persistency of allergy among children who have food allergies.
De Eggesboe and colleagues had previously reported a similar association between Caesarean section and egg, fish and nut allergy.
A more recent study also found that Caesarean delivery was a risk factor for the development of an IgE mediated milk allergy with an odds ratio of 0.42.
For children with a milk allergy it is essential that parents and caregivers know the different names under which milk can be listed in prepared foods. Avoidance of cows’ milk protein is necessary. Furthermore, substituting sheep or goat’s milk is not recommended because of a high degree of cross reactivity with cows’ milk.
Eggesbø M, Botten G, Stigum H, Samuelsen SO, Brunekreef B, Magnus P. Cesarean delivery and cow milk allergy/intolerance. Allergy. 2005;60(9):1172–3.
Sánchez-Valverde F1, Gil F et al. The impact of caesarean delivery and type of feeding on cow's milk allergy in infants and subsequent development of allergic march in childhood. Allergy. 2009 Jun;64(6):884–9. doi: 10.1111/j.1398-9995.2008.01931.x.