Women with low levels of vitamin D are nearly 50% more likely to develop multiple sclerosis than those who get enough, according to a new study published in Neurology. This strengthens findings of existing research showing a link between vitamin D status and MS.
Around 100,000 people in Britain have MS which normally gets diagnosed between the ages of 20 and 40. It is a condition which affects the brain and spinal cord, with symptoms including problems with vision, arm or leg movement, sensation or balance. In worst case scenarios MS can leave people wheelchair-bound by severely damaging their muscles.
It is believed the 'sunshine vitamin' may help to suppress immune cells that attack the body to cause MS
Researchers at Harvard TH Chan School of Public Health in Boston examined blood samples from a large number of women - blood samples from more than 800,000 women in Finland were used, taken originally as part of prenatal testing.
A total of 1,092 women were diagnosed with MS on average 9 years after giving blood samples. They were compared to 2,123 women who did not develop the disease.
Of the women who developed MS, 58% had deficient levels of vitamin D, compared to 52% of the women who did not develop the disease. Researchers found that with each 50 nmol/L increase in vitamin D levels in the blood, the risk of developing MS later in life decreased by 39%.
Those deficient in vitamin D had a 43% higher chance of getting MS than women with adequate levels. The risk was 27% higher for those deficient in vitamin D as compared with those with just insufficient levels.
N.B. Deficient levels of vitamin D were defined as fewer than 30 nanomoles per litre (nmol/L). Insufficient levels were 30 to 49 nmol/L and adequate levels were 50 nmol/L or higher.
Lead author of the study Kassandra Munger states:
"'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."
The body needs vitamin D to help absorb different nutrients
The body needs vitamin D to help absorb different nutrients, and is most commonly absorbed through natural sunlight. It is known that MS is more common in countries further away from the equator, which adds to the thinking that the lack of sunlight and subsequent vitamin D could well be linked to the increased chance of MS.
Dr Mungar concluded: "More research is needed on the optimal dose of vitamin D for reducing risk of MS 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.
It is critically importance to maintain healthy levels of vitamin D intake throughout the year
So as we enter the winter months, in the absence of the sun, it is of critical importance for us to maintain healthy levels of vitamin D intake.
Vitamin D can be obtained through diet by eating oily fish such as tuna, mackerel and salmon, with eggs, meat and fortified products such as cereals and margarine also being great sources.
However, dietary sources alone may not provide sufficient levels of vitamin D. Last year Public Health England recommended that everyone take a 10mcg vitamin D supplement daily.
It is also vitally important to supplement vitamin D orally on a daily basis across the year if you are not spending time outdoors or in the sun. Office workers, pregnant women and the elderly are among those said to be at risk of falling dangerously low on vitamin D.