Children allergic to cow's milk are smaller and lighter: Study

Milk is known for its high content of calcium and is considered good for children's health, but a recent study suggests children who are allergic to cow's milk are smaller and weigh less than those who have allergies to peanuts or tree nuts.

The results from the longitudinal study are believed to be the first to characterise growth patterns from early childhood to adolescence in children with persistent food allergies.

The results of the study were published in the journal of Allergy and Clinical Immunology.

According to Karen A Robbins, MD, lead study author and an allergist in the Division of Allergy and Immunology at Children's National Hospital, "It remains unclear how these growth trends ultimately influence how tall these children will become and how much they'll weigh as adults."

"However, our findings align with recent research that suggests young adults with persistent cow's milk allergy may not reach their full growth potential," Dr Robbins says.

According to the Centers for Disease Control and Prevention, one in 13 US children has a food allergy with milk, eggs, fish, shellfish, wheat, soy, peanuts and tree nuts accounting for the most serious allergic reactions. Because there is no cure and such allergies can be life-threatening, most people eliminate one or more major allergen from their diets.

From November 1994 to March 2015, 191 children were enrolled in the study, 111 with cow's milk allergies and 80 with nut allergies. All told, they had 1,186 clinical visits between the ages of 2 to 12. Sixty-one per cent of children with cow's milk allergies were boys, while 51.3 per cent of children with peanut or tree nut allergies were boys.

In addition to children allergic to cow's milk being shorter, the height discrepancy was more pronounced by ages 5 to 8 and ages 9 to 12. And, for the 53 teens who had clinical data gathered after age 13, differences in their weight and height were even more notable.

"As these children often have multiple food allergies and other conditions, such as asthma, there are likely factors besides simply avoiding cow's milk that may contribute to these findings. These children also tend to restrict foods beyond cow's milk," she adds.

The way such food allergies are handled continues to evolve with more previously allergic children now introducing cow's milk via baked goods, a wider selection of allergen-free foods being available, and an improving understanding of the nutritional concerns related to food allergy.

Dr Robbins cautions that while most children outgrow cow's milk allergies in early childhood, children who do not may be at risk for growth discrepancies. Future research should focus on improving understanding of this phenomenon.