North-south divide in vitamin D deficiency revealed

Women in the north of the UK are more deprived of vitamin D from sunlight compared with their southern counterparts.

Scientists found those living north of the border are exposed to 50 per cent less sunlight during the summer months. This undermines the body's ability to generate vitamin D, which is essential to protect the body from osteoporosis.

The researchers say the findings highlight the need for better public advice on ways to boost vitamin D levels during the winter months.

In the study, more than 500 women between the ages of 55 and 70 living in Aberdeen and Surrey were asked to wear a badge with a film that detected the amount of UVB rays they were exposed to daily.

Between the months of November and April, 40 per cent of women in Aberdeen showed less than the threshold levels of vitamin D needed to protect the body from risk of osteoporosis, compared to only 10 per cent of women in Surrey.

Although the figures fell during the summer months, nine per cent of women in Aberdeen were still deficient in the sunshine vitamin.

Both groups of women obtained similar amounts of vitamin D from their diet alone but this was not enough to make up for the deficit in sun exposure.

Dr Helen Macdonald, from the University of Aberdeen’s Institute of Medical Sciences, said: “Vitamin D is highly important in the prevention of bone diseases such as osteoporosis, helping our bodies absorb more calcium through our diet.

“Studies have also suggested those who are deficient of vitamin D — may be more at risk of diseases including heart disease, cancer and muscular sclerosis.

“Our results showed Caucasian women in the north of the country were significantly more deprived of UVB rays than in the south."

Women should not rely upon diet alone to provide adequate levels of vitamin D. Oily fish and egg yolks are both rich in vitamin D, Dr Macdonald added.

“Dietary sources of vitamin D are important but the vitamin D status in the current diet of women in the UK is unlikely to be adequate, she said.

“We cannot assume that winter requirements of vitamin D are met by the stores accumulated over summer if people do not get enough sunlight to make sufficient vitamin D.

"We need to look at appropriate guidelines regarding safe sunlight exposure, to strike the balance between ensuring adequate protection from the sun and obtaining vitamin D from UVB rays," she added.

The findings are published in the journal Osteoporosis International.

This article was published on Wed 24 November 2010