Pregnant women who have dark skin or wear veils are at high risk of vitamin D deficiency, which can lead to rickets in children, studies in Melbourne have found.
A study reported in the journal of medicine found that a high proportion of dark-skinned and or veiled women had vitamin D levels below the ideal. As well as problems such as rickets for the infants, a deficiency in adults can lead to bone-softening conditions such as osteomalacia and muscle disorders.
Ninety per cent of vitamin D in the body is derived from the chemical reaction that occurs when ultraviolet B light hits the skin. Dark skin does not absorb as much ultraviolet B as light skin, and people who wear clothing that covers all their skin are not exposed to the sun.
Of the 82 women screened, 66 (80 per cent) recorded vitamin D levels below the ideal level. Women who were both dark-skinned and consistently covered (including head, arms and neck at all times) were at particularly high risk, with 91 per cent under the safe level of vitamin D.
When ultraviolet B light hits the skin, blood picks up the initial 'inactive' form of vitamin D and takes it to the kidneys, where it is converted into the active form, a steroid hormone that allows bones to absorb calcium and develop.Only 10 per cent of vitamin D in the body is from dietary sources - which include oily fish, eggs, butter and margarine - and this goes for babies too.