Epidemiological research has suggested that low levels of vitamin D are associated with a variety of serious health conditions including cancer, heart disease, inflammatory disorders, diabetes and dementia.
Another health problem where vitamin D has been thought to play a role is asthma. Research has suggested that vitamin D may be important for the immune system and for lung function during early development.
Could a Mother’s Vitamin D Supplement Prevent Asthma in her Baby?
To answer the question of whether prenatal vitamin D supplements might help prevent asthma in babies, investigators in Denmark and the U.S. carried out randomized controlled trials. In both studies, all the pregnant volunteers got prenatal vitamins with 400 IU vitamin D. Likewise in both trials, the women were randomized to get placebo or additional vitamin D. The children were followed up to age three.
The Danish Results:
In the Danish study, the women were given 2400 IU vitamin D. About 16% of their children had persistent wheezing, compared to 20% of those whose mothers took placebo pills. That difference was not significant.
The American Results:
In the US study, the experimental dose of vitamin D was higher, at 4000 IU. By age three, 24% of the children exposed to extra prenatal vitamin D had developed recurrent asthma, compared to 30% in the placebo group.
These results fall shy of statistical significance. They simply are not clear enough to tell for sure whether prenatal vitamins should contain more than 400 IU of vitamin D to reduce the risk of asthma in the children. (Current US standards offer a recommended dietary allowance, RDA, of 600 IU of vitamin D for pregnant women and nursing mothers.) More research is needed to resolve this question.
JAMA, Jan. 26, 2016, also here and here
Those with an interest in the topic of supplementation may wish to listen to our one-hour interview with Tieraona Low Dog, MD, author of Fortify Your Life: Your Guide to Vitamins, Minerals, and More.
