Vitamin D in Moms-to-Be: The Effect on Kids' Asthma

Vitamin D supplementation in pregnant women may not change asthma risk in their children

/ Author:  / Reviewed by: Jennifer Gershman, PharmD, CPh

(RxWiki News) Could the vitamin D in mom's diet during pregnancy affect her children's future health? Regarding asthma, that question might have been answered.

New studies from Denmark and the US looked at whether supplementing mothers' diets with vitamin D affected the rate at which children developed asthma and persistent wheezing. Neither study showed a significant impact, although the Denmark study did suggest that vitamin D decreased episodes of troublesome lung symptoms.

Asthma is among the most common chronic medical problems in children. Vitamin D deficiency is also common in western society, possibly due to lack of exposure to sunshine and low vitamin D in the diet. Vitamin D has immune system effects. Researchers have speculated that vitamin D deficiency during pregnancy may be linked to asthma in children.

Hans Bisgaard, MD, DMSc, of the University of Copenhagen in Denmark, led the first study of 623 women and 581 children.

In addition to a standard dose of 400 IU/d, half the women in this study received an additional 2,400 IU/d of vitamin D. The other half received a placebo, or fake pill. The women's children were followed for three years.

Sixteen percent of the children developed persistent wheeze in the vitamin D group — compared to 20 percent in the placebo group.

Children whose mothers received extra vitamin D had fewer episodes of troublesome lung symptoms. However, other immune system problems like asthma, eczema and allergies remained unchanged.

Dr. Bisgaard and colleagues noted that this was a small study and called for further research.

Augusto A. Litonjua, MD, MPH, led the second study at Brigham and Women’s Hospital in Boston.

Dr. Litonjua and colleagues divided 881 women into two groups. Both groups received 400 IU/d of vitamin D. The first group received an additional 4,000 IU/d. The second group received a placebo.

Of 810 babies, 24 percent in the vitamin D group developed asthma — compared to 30 percent in the control group. Noting that this was also a relatively small group, Dr. Litonjua and team called for further study.

In an editorial about these studies, Erika von Mutius, MD, MSc, of Ludwig Maximilians University in Munich, Germany, and Fernando D. Martinez, MD, of the University of Arizona, Tucson, wrote that "... it is too early to know if these findings indicate the potential for vitamin D supplementation to have any role in reducing the risk of asthma. For both trials, longer-term follow-up will be necessary to determine if maternal vitamin D supplementation in pregnancy might have any effect on risk of asthma during the early school years, if not beyond.”

Both studies and the editorial were published in the January issue of JAMA.

The US study was funded by the National Heart, Lung and Blood Institute and the National Centers for Advancing Translational Sciences. Several of the study authors received grants from the National Institutes of Health and/or fees from companies that make vitamin D supplements or asthma drugs, such as Aerocrine, GlaxoSmithKline, Genentech/Novartis and Merck.

The Denmark study was funded by various sources, such as the Lundbeck Foundation, Danish State Budget, Danish Council for Strategic Research, Danish Council for Independent Research and Capital Region Research Foundation. Dr. Bisgaard received consulting fees from Chiesi, which makes drugs used to treat asthma.

Review Date: 
January 22, 2016
Last Updated:
January 26, 2016