WOMEN thinking of becoming pregnant have been urged to ensure they are getting enough vitamin D, as findings suggest deficiency in pregnancy may cause the baby to develop schizophrenia in later life.
The results, unveiled at a conference in Sydney yesterday, suggests vitamin D - previously associated mainly with building strong bones and preventing rickets - may have a far wider role than experts thought. Vitamin D is made in the skin when exposed to sunlight. Some foods - mainly oily fish and some fortified milk and dairy products - also contain the nutrient, which can also be taken in dietary supplements.
Lead researcher Darryl Eyles, of the Queensland Centre for Mental Health Research, said that because the latest results were based on work on rats, a link between vitamin D deficiency and schizophrenia in humans remained to be proved. "However, there are compelling indicators that women considering becoming pregnant should ensure they have moderate exposure to sunlight, or supplement their diets with vitamin D-fortified dairy products before they conceive," he said.
"It is becoming clearer that low developmental vitamin D is a candidate risk factor for later onset neuropsychotic disease (such as schizophrenia) and degenerative conditions such as multiple sclerosis. This research clearly has emerging implications for public health interventions."
But the findings have already prompted cancer experts to warn women not to interpret the results as carte blanche to ignore existing healthy sun exposure limits. Cancer Council Australia CEO Alan Coates said people could get "all the vitamin D you need" in less time than it took to get sunburnt.
"We say a little bit of sun isn't harmful - but enough to burn you certainly is," Professor Coates said.
In the study on four groups of 24 pregnant rats, the researchers found that if the mothers were deprived of vitamin D from the point of conception, that precipitated abnormal behaviour in the grown-up pups, analagous to that seen in schizophrenia - even though the pups themselves had adequate vitamin D. Giving vitamin D to conceiving rats previously deficient prevented these abnormalities.
Dr Eyles said the findings gave "biological plausibility" to the theory that vitamin D deficiency in the uterus and schizophrenia were linked. He is about to travel to Denmark to conduct research on blood samples of babies born over the past 30 years, which he says should test his hypothesis.
Ian Hickie, professor of psychiatry and director of the Brain and Mind Research Institute, said it was "an interesting idea ... but it's early days to be suggesting that this may have a major preventive ... effect".