Women with low levels of vitamin D are nearly 50 per cent more likely to develop multiple sclerosis than those who get enough, according to a study.
The findings could help to explain why there are higher rates of the disease among those in the North who get less sunlight, which helps the body make vitamin D.
It is believed the 'sunshine vitamin', also found in eggs, red meat and oily fish, may help to suppress immune cells that attack the body to cause MS. The disease can leave people wheelchair-bound by severely damaging their muscles.
Women with low levels of vitamin D are nearly 50 per cent more likely to develop multiple sclerosis than those who get enough, according to a study
US researchers at Harvard TH Chan School of Public Health in Boston examined blood samples from more than 3,200 women, who are two to three times more likely to be diagnosed with MS than men.
Those deficient in vitamin D had a 43 per cent higher chance of getting MS than women with adequate levels. The risk was 27 per cent higher for those deficient in vitamin D as compared with those with just insufficient levels.
Lead author Dr Kassandra Munger said: 'We do know there is a higher incidence of MS in more northern countries, the further you move away from the equator.
'One hypothesis put forth for this is that these populations have a lack of vitamin D due to a lack of sun exposure.
'Our study adds to the evidence that vitamin D deficiency is a risk factor for MS and that correcting this in women of reproductive age may reduce their risk of developing it. People should discuss with their doctor whether they need a supplement.'
Office workers, pregnant women and the elderly are among those said to be at risk of falling dangerously low on vitamin D.
The findings could help to explain why there are higher rates of the disease among those in the North who get less sunlight, which helps the body make vitamin D
The sunshine vitamin is measured in nanomoles, and people are deficient if they have less than 30 nanomoles per litre of blood. This can be raised to adequate levels of 50 nanomoles with a daily tablet.
The American study, published in the journal Neurology, used blood samples from women in Finland.
Dr Munger said: 'More research is needed… but striving to achieve vitamin D sufficiency over the course of a person's life will likely have multiple health benefits.'
Dr David Schley, of the MS Society, said the study shows that vitamin D remains a crucial area of research.