Pregnant women should take vitamin D supplements to protect their offspring from multiple sclerosis, a UK-based expert has urged.
Recent studies have shown that exposure to sunlight - key in the production of the vitamin by the body - during early life protects against the uncurable disease.
This is why many experts believe that the lack of vitamin D in people living in northern, less sunny climates is responsible for their increased risk of the disease.
An Oxford University team reported in the 7 December issue of last year's BMJ that babies born in Scotland in May have the highest risk of developing MS while children born in November had the lowest risk.
Their research on more than 29,000 patients in Scotland and Canada concluded that a mother's exposure to sunlight during pregnancy may be a factor in whether her child develops the neurological condition in later life.
Last year a 20-year survey of more than 185,000 American women found that those who took multivitamins containing vitamin D were 40 per cent less likely to develop MS.
Dr Abhijit Chaudhuri, a neurologist at Glasgow's Southern General hospital, claims that modifying an important environmental factor - sunlight exposure and vitamin D intake - could be a practical and cost-effective way to reduce the burden of the disease in future generations.
"In areas of high MS prevalence, dietary supplementation of vitamin D in early life may reduce the incidence of MS," he writes in the latest issue of Medical Hypotheses (vol 64, issue 3 , pp 608-618)."In addition, like folic acid, vitamin D supplementation should also be routinely recommended in pregnancy."
Chaudhuri believes that other northern countries such as Greenland and Norway have lower MS rates than Scotland because of higher consumption of oily fish, which is rich in vitamin D and compensates for the lack of sunlight.
An estimated 2.5 million people in the world have MS but it is much more common in women than men - at a ratio of 2 men to 3 women, according to the Multiple Sclerosis International Federation.
The cause of the disease is unknown but researchers do know that the number of cases of MS increases the farther you get from the equator.