Midday sun is good for vitamin D levels, say scientists
say scientists with new research, which will add fuel to the
growing row between vitamin D supporters and skin cancer
The research, led by Ann Webb, an expert in ultra-violet radiation at the University of Manchester, supports claims that exposing unprotected skin to the sun for short periods helps the body to produce essential vitamin D.
Dr Webb has produced new figures which not only predict when is the best time to expose unprotected skin to the sun in order to maximise vitamin D production, but also for how long - depending on location.
She has calculated that '10 to 15 minutes at noon' is the optimum time for the average person in the UK to spend in the sun without the use of sunscreen.
However government health officials and skin cancer charities believe that exposing skin to the sun during the middle of the day - the time recommended by Dr Webb - puts fair-skinned people at risk of skin damage. Vitamin D levels can instead be raised by supplements or fortified foods.
Experts gathered recently by the American Academy of Dermatology Association said that recommending increased exposure to sunlight is "highly irresponsible".
Speaking at the Academy's Melanoma/Skin Cancer Detection and Prevention Month news conference, dermatologist Vincent A. DeLeo from Columbia University in New York said: "It is known that there is a high risk of developing skin cancer from repeated and intentional ultraviolet B exposure to boost vitamin D levels; the latter can be safely achieved by nutritional supplements."
There is growing evidence to show that many people in the northern hemisphere, especially the elderly and darker-skinned individuals, may be lacking sufficient vitamin D.
This has triggered the theory that increasing use of sun protection creams is keeping vitamin D levels too low.
Vitamin D promotes the absorption of calcium and phosphate from food and is essential in the formation of bones and teeth. A deficiency of vitamin D leads to a failure of the bones to grow and causes rickets in children and osteoporosis in adults, set to become a global healthcare problem give the ageing population.
Recent research also suggests that vitamin D can help reduce the risks of colon, breast and prostate cancer.
"The two sources of vitamin D are through your skin or through foods like sardines (fatty fish), but because our everyday diet isn't very rich in the vitamin it is essential that we get it from the sun," said Dr Webb.
Recommendations for sun exposure are likely to prove less popular among health officials than the approach currently used by Denmark. The country has issued information and advice to targeted groups to increase levels of vitamin D in the diet or through supplements.