Getting out in the sun and eating foods rich in vitamin D could reduce the chance of having a stroke, according to research

By Stephen Adams, Medical Correspondent

American scientists have found that a lack of vitamin D – which is naturally manufactured by the skin when exposed to strong sunlight, and is also found in foods including nuts and oily fish – can raise stroke risk by more than a fifth.

They discovered that the quarter of people with the lowest vitamin D levels were at a 22 per cent higher risk of having a stroke than those in the top quarter. Low vitamin D levels increased the chance of having the more common type of stroke, known as an ischaemic stroke, where a clot becomes lodged in a brain blood vessel.

However, low levels did not affect the likelihood of the other type, called a haemorrhagic stroke, caused by a burst brain blood vessel.

The University of Hawaii team based their conclusions on a 34-year study of 7,500 middle-aged and elderly Japanese-American men living in the islands.

Participants were ranked on vitamin D levels purely on what they said they ate, not on how much sun they said they got.

Dr Gotaro Kojima, one of the researchers, said getting vitamin D from food or supplements was of greater importance for older people because synthesizing the vitamin from sunlight becomes more difficult with age.

He said: “Our study confirms that eating foods rich in vitamin D might be beneficial for stroke prevention.”

Writing in Stroke, a journal of the American Heart Association, he and colleagues advised: “Based on the results of this and other epidemiological studies, higher vitamin D intake or vitamin D supplementation may be beneficial for stroke prevention.”

However, they said large randomised controlled trials, specifically designed to test the theory, were needed.

© Telegraph Media Group Limited 2012