Why too little sun is sapping our strength

We’re not getting enough Vitamin D

SCOTLAND’S bad weather may have helped build our character, but it could now be sapping the nation’s strength.

Overcast skies are to blame for a Vitamin D shortage which weakens muscles, a new study suggests.

Scientists at Aberdeen University found even a small increase of the sunshine vitamin in volunteers’ blood improved muscle tone.

They believe that if everyone met the national daily guidelines, there could be an increase of up to 20 per cent in our strength.

Scotland gets a third less ultraviolet radiation – the chief source of Vitamin D – from the Sun than the rest of the UK due to our higher latitude and more persistent low cloud cover. Lack of Vitamin D has been blamed for our poor health record and linked to conditions including MS and high blood pressure.

Last year, the Scientific Advisory Commission on Nutrition advised Scots to take supplements all year round, particularly in autumn and winter.

The recommended level of Vitamin D is 50 nanomols per litre (nmo/L) of blood – with half the population failing to reach half that figure.

Report co-author Dr Stuart Gray said: ‘With supplementation you might expect an increase of Vitamin D in the region of 25-30 nmol/L and that would potentially translate into an increase of about 20 per cent in somebody’s strength.’

The study followed more than 70 overseas students staying in Scotland. The volunteers, who had regular blood tests, were asked to carry out muscle strength tests throughout the 15-month trial.

There were seasonal fluctuations, but Dr Gray said: ‘The average Vitamin D level was 24 nmol/L. To be honest, that is not far off what we would see, depending on the time of year, in the Scottish population anyway.

‘People often use 50 as a target to reach – so with supplementa- tion you could get these people up to 50. We might then expect their muscle strength to increase by around the 15 to 20 per cent mark as well.’

Scientists are unsure exactly why Vitamin D affects muscle strength, but it may be linked to a receptor in body tissue. It could also be linked to the role the vitamin plays in building bone, regulating calcium absorption.

Professor Helen Macdonald, who also co-authored the report, published in Osteoporosis International, said: ‘Previously, we would say if you are a normal healthy adult we would not worry about Vitamin D. You would make enough in the summer to get through the winter.

‘Now we realise you cannot spot who is getting enough sunlight or not. Those people who most need it don’t tend to take supplements – so some think maybe we should fortify foods and get it that way.’

This week, a major study in the BMJ suggested adding Vitamin D to food would significantly cut NHS costs.

Vitamin D is found in foods such as oily fish, red meat, liver and egg yolks.

‘Maybe we should fortify foods’