Obese women who become pregnant may not be passing on enough vitamin D to their babies, a new study indicates.

Vitamin D is essential for healthy bones, but is present in very few foods. It is also known as the sunshine vitamin, because it is made in the body when ultraviolet rays from sunlight strike the skin.

The vitamin is fat soluble and previous research has suggested that obese people have lower levels of it in their blood.

This latest US study found that babies born to mothers of a healthy weight had at least a 30% higher amount of vitamin D in their bodies compared to babies born to obese women.

This was despite the fact that both groups of mothers had similar levels of vitamin D in their own bodies at the end of their pregnancies.

"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," explained lead scientist, Dr Jami Josefson, of Northwestern University in Chicago.

She said that it may be possible that vitamin D ‘gets sequestered in excess fat and is not transferred sufficiently from an obese pregnant woman to her baby'.

Dr Josefson said that more studies need to be carried out to investigate the role of vitamin D in babies' health.
However, she emphasised that these findings indicate that obese women ‘may need larger amounts of vitamin D supplementation to provide their babies with sufficient levels of vitamin D while they are in the womb'.

Details of these findings are published in the Journal of Clinical Endocrinology and Metabolism.

Since 2011, the HSE and Department of Health here have advised the parents of infants under 12 months of age to give them a daily supplement of vitamin D. For more information on this, click here