Australasian Science Magazine

By Stephen Luntz

Further evidence has emerged of the importance of healthy maternal vitamin D levels during pregnancy, with children whose mothers had low concentrations of vitamin D in their blood during their second and third trimester more likely to struggle with speech.

“The developing baby is completely reliant on the mother for its vitamin D levels, and what we have shown is that this might have an impact on the child’s brain development,” says A/Prof Andrew Whitehouse of the Telethon Institute for Child Health Research.

Blood samples were taken from 740 pregnant women almost 20 years ago and tested for vitamin D levels. The Telethon Institute has since tracked the children, looking for signs of lasting effects.

Pediatrics has published Whitehouse’s results, including the finding that children whose mothers were vitamin D-deficient are twice as likely to experience language difficulties. This is particularly concerning because vitamin D levels have dropped substantially among Australian women over the past 20 years, partially as a result of anti-skin cancer campaigns.

“The latest advice from the Cancer Council is that, while people shouldn’t go out in the summer sun unprotected, they should get half an hour a day of sunlight in winter,” Whitehouse says. However, he does not know if this message is getting through. At the time of the study the low vitamin D levels were overwhelmingly in winter.

The study also looked for evidence of behavioural or emotional problems resulting from vitamin D deficiency in utero. No correlation was found despite other evidence indicating a substantially increased risk of schizophrenia (AS, Dec 2010, p.5). “Although schizophrenia has subtle signs during childhood, it does not usually strongly affect behaviour until the late teens for males and late twenties for women,” Whitehouse says. “We will be following this cohort through to see if there are effects as they get older.”

Whitehouse says Prof John McGrath’s discovery that vitamin D deficiency affects brain development in animals was important for his research, but there is also plenty of evidence of physical effects, such as a relationship with asthma and weak bones.

Epidemiological research has shown that children born during winter and spring at high latitudes are more vulnerable to schizophrenia, but Whitehouse says this is harder to measure for language, although he hopes to collaborate on studies of Scandinavian children born in different seasons.