Carlos A. Camargo at Harvard Medical School and colleagues published a study in the Jan 2011 issue of Pediatrics suggesting that sufficient prenatal vitamin D may help prevent infections in newborn babies and young children.

The study was intended to reveal an association between cord blood 25-hydroxyvitamin D levels and risk of respiratory infection, wheezing and asthma. The researchers say in their report that higher maternal intake of vitamin D during pregnancy has already been linked with a lower risk of wheezing in babies.

For the study, the researchers tested cord blood samples from 922 newborns for 25(OH)D, a form of vitamin D.  Parents were asked to report respiratory infections at 3 months of age , wheezing at 15 months and thereafter annually.

The cord blood levels of 25(OH)D were inversely associated with risk of respiratory infection by 3 months of age and wheezing risk by 15 months, three years and five years of age.

Compared with children who had the highest levels of vitamin D in their cord blood, greater than 75 nmol/L, those who had only less than 25 nmol/L were nearly twice as likely to suffer respiratory infection by three months of age.

The associations remained the same after adjustment for more than 12 possible confounders.

However, vitamin D levels in cord blood were not associated with incident asthma by five years of age.

All the study results suggest that pregnant women need to have sufficient exposure to sunshine, which is needed for the biosynthesis of vitamin D, during pregnancy. If that is not possible, high doses of vitamin D supplements should be taken.

Dr. John Cannell, Director of Vitamin D Council and a vitamin D expert, says that vitamin D deficiency has been associated with many diseases including cancer, heart disease, autism, depression, hypertension, diabetes, autoimmune diseases, stroke, osteoporosis, muscle weakness, birth defects, periodontal disease among others.

Scientists including Dr. Cannell have proved that vitamin D plays a role in innate immunity against infectious viruses and bacteria.

Dr. Cannell and many other vitamin D experts criticized the Institute of Medicine for their recent recommendations on vitamin D saying the recommended doses are way too low to have an protective effect against diseases.

David Liu