Many babies born short of vitamin D

Even in the womb, babies face a high risk of vitamin D deficiency, a new study finds. The sunshine vitamin is a building block for a hormone that not only helps build bone and muscle, but also fights infections and many chronic diseases.

Lisa M. Bodnar of the University of Pittsburgh School of Public Health and her colleagues collected blood samples from 400 first-time moms early in their pregnancies and again at delivery. Half the women were black, and half were white.

More than 90 percent of the participants took multivitamins—including vitamin D—during pregnancy. Half that group had also taken such vitamins before becoming pregnant. But by the end of their pregnancies, only 4 percent of the black women and 37 percent of the whites had vitamin D blood concentrations deemed sufficient for good health, the researchers report in the February Journal of Nutrition. Tests of umbilical cord blood showed that just 17 percent of black infants and half the white ones had sufficient vitamin D at birth.

The team expected to see a racial difference because heavily pigmented skin absorbs less sun and produces less vitamin D than light skin does. However, sunlight in northern latitudes is too weak in fall and winter to spur adequate vitamin production even in whites. The authors say that their findings could partly explain a reemergence of rickets among black children in the United States.