High-Dose Vitamin D Supplementation Does Not Prevent Allergic Sensitization of Infants

To examine the effect of post-natal vitamin D supplementation on the development of allergic disease in the first year of life.

The study included 987 infants born to mothers of Northern European descent in Finland. Inclusion criteria included term birth with an appropriate weight for gestational age and newborns not requiring higher levels of care. The study population was followed from birth until 12 months of age.

The study was a double-blinded randomized control trial. The study population was randomly divided into two vitamin D supplementation groups: one group received daily vitamin D₃ of 400 IU (10 μg) and the other group received daily vitamin D₃ of 1200 IU (30 μg). At the time of delivery, pregnancy serum samples and cord blood were analyzed for 25(OH)D concentration. At 12 months of age, 25(OH)D concentration was measured for each infant as well as specific IgE antibodies to food allergens and aeroallergens. Parents of the 12-month-old infants also completed an allergy questionnaire that included questions regarding whether the infant had ever been diagnosed with food allergy, asthma, wheezing, or eczema.

There was no statistically significant difference between allergic diseases in infants receiving different doses of vitamin D supplementation. IgE sensitization at 12 months of age to food allergens and aeroallergens was observed in 16% and 4% of all infants enrolled in the study, respectively. There was no difference between the two groups in the development of eczema, asthma, or IgE sensitization to food allergens or aeroallergens. Physician-diagnosed cow milk allergy was higher in the group receiving higher vitamin D supplementation, but there was no difference in specific IgE to cow milk between the groups. In infants with cord blood 25(OH)D concentration greater than 100 nmol/L, the risk for IgE sensitization to food allergens was higher, compared with those with a lower cord blood vitamin D.

Increased post-natal vitamin D supplementation does not decrease the risk of allergic disease in infants. There was an increased risk of cow milk allergy in infants with higher vitamin D levels and an increase in allergic disease in those with higher cord blood vitamin D.

The incidence of allergic disease has drastically increased over the past twenty years, and vitamin D deficiency has been hypothesized as a potential cause. Multiple studies have been conducted that demonstrate an association between low vitamin D levels and allergic disease but it is not clear if this is a causal relationship. This study is the first randomized control trial looking at the effect of vitamin D supplementation on the development of allergic disease in infants, and further studies need to be done to include a more diverse population and those at higher risk for developmental of allergic disease.