The results of a randomized controlled trial were evaluated in a study published in June 2022. In the trial the effects of prenatal vitamin D supplementation were examined primarily with a view to children’s bone density. The fact that vitamin D has an effect on the immune system and consequently on skin condition has long been known. This time scientists were interested in how the mother’s vitamin D supplementation influenced the occurrence of childhood eczema which affects one in six young children on average.

More than 700 pregnant women participated in the trial. They were divided into two groups. Starting from the 14^th week of pregnancy up to the day of giving birth the members of one group were given 1000 IU vitamin D3 while the members of the other group received placebo.

In the case of the children whose mothers took vitamin D3, by their 1^st birthday the occurrence of eczema became 45% lower so the risk decreased nearly by half. Later, between the ages of 2 and 4 the initial results dropped to 25% which suggests that the protection provided by a higher vitamin D level weakened because the children didn’t get vitamin supplementation.

This finding could also be supported by the fact that for children who were breastfed for longer than a month the risk of eczema decreased even more significantly by the time they reached 1 year of age, altogether by more than 50%. Most probably the mothers taking vitamin supplementation during breastfeeding filled their babies up with vitamin D.