In a recent study published in the European Journal of Clinical Nutrition, researchers from Finland examined whether adolescents who suffered from cow’s milk allergy during their infancy but were now tolerant to cow’s milk continued to consume lower amounts of dairy as compared to their peers who were not allergic to cow’s milk in their infancy.
They also examined the vitamin D concentration in these adolescents and potential associations between cow’s milk allergy and height differences.
Study: Dairy consumption and vitamin D concentration in adolescents with challenge-confirmed cow’s milk allergy during infancy. Image Credit: goffkein.pro/Shutterstock.com
Background
Between 0.5% and 2.4% of children in Europe are diagnosed with cow’s milk allergy in their infancy and are required to follow a milk-elimination diet. While milk is a natural source of essential nutrients such as calcium, protein, and iodine, in many countries, it is also fortified with vitamin D3 or cholecalciferol.
Liquid dairy products and fat spreads in Finland are fortified with vitamin D3, and the serum concentrations of 25-hydroxyvitamin D among children are determined largely by milk consumption.
However, cow’s milk allergy is also associated with lower vitamin D levels among Finnish children. Furthermore, while most children become tolerant to cow’s milk by the age of three years, studies have indicated that some remain allergic and that the milk elimination diet has been linked to shorter heights.
About the study
In the present study, the researchers examined whether the implementation of milk elimination diets during the first three years of life in children suffering from cow’s milk allergy had lasting effects on the food habits of these children when they reach adolescence, as well as on their serum vitamin D concentration levels and growth.
Studies have reported that food preferences in children are generally formed in the first three years of life, and children who followed the milk elimination diet during early childhood due to cow’s milk allergy showed lower overall variation in their diet.
However, the data on the dietary habits of adolescents who were allergic to cow’s milk and followed a milk elimination diet during their infancy is limited.
Furthermore, examining the dietary preferences of adolescents with a history of cow’s milk allergy is important since adolescence is the developmental stage when an individual undergoes various transitional changes, including dietary preferences.
To compare the dietary preferences and dairy product intake between adolescents with and without a history of cow’s milk allergy during their infancy, the researchers invited adolescents who had participated in a previous randomized control trial examining cow’s milk allergy in infants. They also recruited age-matched controls without cow’s milk allergy.
Food-frequency questionnaires were used to collect data on vitamin D sources in the diet and cheese consumption. The questionnaire on vitamin D sources assessed the quantity of milk consumed in the diet directly, with cereal, in the form of yoghurt or porridge, and added to tea or coffee.
Other vitamin D sources in the diet, such as eggs and egg-based food products, meat, poultry, fish, cooking fat, fat spreads, and wild mushrooms, were also examined in this questionnaire. The questionnaires were also used to calculate the Healthy Eating Index.
Anthropometric variables of the participants, such as height and weight, were measured, and blood samples collected after overnight fasting were analyzed using immunoassays to determine 25-hydroxyvitamin D levels in the serum.
Results
The study found that adolescents who had cow’s milk allergy in their infancy did not face milk reintroduction failure during their adolescence or vitamin D insufficiency compared to their peers who did not suffer from cow’s milk allergy when they were infants.
Furthermore, no differences were observed in the Healthy Eating Index scores between the two groups. While the intake of dairy products in liquid form for all the participants was below the recommended limits in Finland, the vitamin D levels in the serum did not indicate any insufficiency.
The study also found that the body mass index and height standard deviation scores indicated no difference between adolescents who were allergic to cow’s milk during infancy and those who were not.
These results were supported by previous studies that showed that overall growth in children with cow’s milk allergies caught up to normal levels as soon as the milk elimination diet had been discontinued.
The median intake of dairy products such as milk also did not differ significantly between adolescents with a history of cow’s milk allergy and those not allergic to cow’s milk during their infancy.
Conclusions
The study showed that the milk elimination diet used to treat cow’s milk allergy in infants did not significantly affect the reintroduction of milk and dairy products into the diet during adolescence or impact their vitamin D levels or growth.
Furthermore, the current methods to manage cow’s milk allergies seemed adequate in countering the nutritional disadvantages of the cow’s milk elimination diet.
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