More Vitamin D May Help Moms Prevent Asthma in Children


Mothers-to-be who are worried about their child developing asthma early in life may want to up their vitamin D intake, a new study suggests.

Appearing in the Journal of Allergy and Clinical Immunology, the study found that pregnant women who took extra vitamin D supplements during their second and third trimesters gave birth to babies whose blood exhibited signs of enhanced immune activity, a key marker for avoiding respiratory illnesses such as asthma.

An inhaler used to treat asthma attacks. Courtesy: Neil Turner/Flickr, CC BY 2.0

“The majority of all asthma cases are diagnosed in early childhood implying that the origin of the disease stems in fetal and early life,” said study author Catherine Hawrylowicz, a professor at King’s College London.

The new findings mark the first time that scientists have been able to positively identify a physical reaction in babies following vitamin D use among women.

“Studies to date that have investigated links between vitamin D and immunity in the baby have been observational. For the first time, we have shown that higher vitamin D levels in pregnancy can effectively alter the immune response of the newborn baby, which could help to protect the child from developing asthma. Future studies should look at the long-term impact on the immunity of the infant,” added Hawrylowicz.

Behind the Study

The researchers divided the study participants into two groups, both of whom received vitamin D supplements. Yet while the first group took 400 units, or the amount of vitamin D that’s currently recommended during pregnancy, the second group took about 4,400 units of the vitamin after the 18-week mark.

Fatty fish, such as salmon and tuna, as well as eggs and some dairy products are just some of the many ways to incorporate more Vitamin D into your diet. Image courtesy: Maggie Hoffman/Flickr, CC BY 2.0

At birth, the researchers tested the composition of each baby’s cord blood and found that those whose mothers consumed larger amounts of vitamin D showed enhanced signs of disease protection.

“Vitamin D exposure during fetal development influences the immune system of the neonate, which can contribute to protection from asthma-related, including infectious, outcomes in early life,” wrote the study authors.

That’s critical because the early intervention can help protect children from developing asthma when they’re young. About 8 percent of the population, or roughly 25 million people, have asthma in the United States, according to the American Academy of Allergy, Asthma and Immunology.

In addition to supplementation, Vitamin D can be found naturally in foods such as fatty fish, eggs and some dairy products.

Related: Vitamin D Deficiency May Cause Early Menopause

The researchers are cautiously optimistic that their findings can help move the needle on asthma prevention.

“Vitamin D is a promising area of research for asthma, however this study is just the first step of many needed to explore this topic,” said Dr. Samantha Walker, Director of Research and Policy at Asthma UK, a research organization based in England.

“Although this study shows that vitamin D supplementation in pregnancy may improve immune responses, much more research is needed to prove whether this does in fact lead to reduced asthma rates later in life,” added Walker.

Walker also noted that “years of underfunding in research mean that we still do not understand what causes asthma, or have the ability to predict which babies will go on to develop asthma. This is urgently needed if we are to develop strategies to treat, and ultimately prevent asthma in children.”

Related: Too Much Processed Meat Could Make Asthma Worse