A new study finds a high incidence of vitamin D deficiency in breast-fed babies, mostly during winter. Such a deficiency limits the body's use of calcium, which is essential for healthy bones and teeth.
As part of a trial of iron supplementation, Ekhard E. Ziegler of the University of Iowa in Iowa City and his colleagues regularly took blood samples over 2 years from 84 newborns who were initially breastfed exclusively. The researchers noticed that few infants were getting supplemental vitamin D.
The scientists evaluated vitamin D in the infants' blood. They report in the August Pediatrics that 78 percent of breastfeeding youngsters not receiving vitamin D in supplements were deficient in that nutrient during winter, but only 4 percent showed the deficiency in summer. None of the 49 infants getting vitamin supplements showed the deficiency at any time.