Researchers at the University of Pittsburgh say that even regular use of prenatal multivitamin supplements is not adequate to prevent vitamin D deficiency during pregnancy. Writing in the Journal of Nutrition, they warn that vitamin D deficiency in newborns is associated with rickets as well as increased risk for diabetes, asthma and schizophrenia. Worryingly, the researchers found that vitamin D insufficiency was widespread among women during pregnancy, particularly in the northern latitudes. "More than 80 percent of African-American women and nearly half of white women tested at delivery had levels of vitamin D that were too low, even though more than 90 percent of them used prenatal vitamins during pregnancy," said Lisa Bodnar, lead author of the study. "The numbers also were striking for their newborns - 92 percent of African-American babies and 66 percent of white infants were found to have insufficient vitamin D at birth."
Bodnar explained that a newborn's vitamin D levels were completely reliant on vitamin D from the mother. "Not surprisingly, poor maternal vitamin D status during pregnancy is a major risk factor for infant rickets, which again is becoming a major health problem," she noted.
Vitamin D is made by the body in reaction to sunlight exposure and it has long been known that vitamin D deficiency is more common among darker-skinned individuals, particularly in more northern latitudes, where less ultraviolet radiation reaches the Earth. Lack of sunlight means that deficiency is more than three times as common in winter than in summer. Vitamin D is also found naturally in fatty fish but few other foods. Because of the lack of alternative sources, adequate sun exposure remains critical.
"Our study shows that current vitamin D dietary intake recommendations are not enough to meet the demands of pregnancy. Improving vitamin D status has tremendous capacity to benefit public health," Bodnar concluded.
Source: University of Pittsburgh
