Obese moms may put babies at risk of vitamin D deficiency

Researchers from Northwestern University found that babies born to lean mothers had a third higher amount of vitamin D compared to babies born to obese moms.

Vitamin D is fat-soluble, and previous studies have found that people who are obese tend to have lower levels of the vitamin in their blood.

In this study, both obese and lean mothers had very similar levels of vitamin D at the end of their pregnancies, yet obese women transferred less vitamin D to their offspring compared to lean women.

"Nearly all of mothers in this study reported taking prenatal vitamins, which may be the reason why their own vitamin D levels were sufficient, but the babies born to the obese mothers had reduced levels of vitamin D," said Jami L Josefson, first author of the study.

"It's possible that vitamin D may get sequestered in excess fat and not transferred sufficiently from an obese pregnant woman to her baby," Josefson said in a statement.

Recent studies have linked low vitamin D in adults to an increase in autoimmune diseases, inflammation and obesity.

Researchers included the analysis of the mothers' and babies' vitamin D levels. Sixty-one women who gave birth at Prentice Women's Hospital of Northwestern Memorial Hospital in Chicago participated in the study.

They all had pre-pregnancy body mass indexes that were either normal or obese.

Vitamin D levels were measured from blood collected from mothers at 36 to 38 weeks gestation and umbilical cord blood was collected from their babies immediately following birth.

Body fat, weight and volume of the babies were also measured.

"The range of body fat of the babies in this study was similar to other studies reporting neonatal body fat. What was novel about this study was that we found babies born with higher vitamin D levels had more body fat," Josefson said.

"That's in contrast to studies in children and adults who have an inverse relationship between levels of vitamin D and body fat, where the higher their vitamin D, the lower their fat," Josefson added.

The study was published in the Journal of Clinical Endocrinology and Metabolism.