Sunlight vit d prevents breast colon lung prostate cancer
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Doctors see a sunnier outlook on cancer front
By Peter Pallot
Doctors who believe that the campaign to avoid the sun may be over zealous have received another boost in a study which found that the recovery rates for lung cancer patients were much better if they were operated on in the summer.
The medical profession appears to be split over the amount of sunlight we need, with increasing numbers saying "sunlight robbery" has gone too far. Divisions among specialists opened up two months ago when Cancer Research UK launched its SunSmart drive. Its aim is to avert 21,000 projected cases of skin cancer a year by 2035.
Critics said the uncompromising line adopted by the charity was over the top. They argued that, while sunburn itself was unequivocally bad, moderate exposure was important to cancer prevention because rays prompted the production of vitamin D.
Now the new study from researchers at Harvard Medical School who found that lung cancer patients operated on in the summer months doubled their chances of five-year survival compared to those operated on in winter.
A meeting of the American Association for Cancer Research heard that the study - involving 456 early-stage patients - was structured to exclude distorting factors such as diet and surgical techniques.
The researchers therefore concluded that the happier outcome for summer patients was due to sunlight boosting vitamin D levels.
However, head researcher Dr Wei Zhou said: "This study in no way suggests that people should try to time their cancer surgeries for a particular season - that would obviously be impossible."
Vitamin D is thought to slow cell growth and spread. Statistics show that the sunnier the climate in which fair-skinned people live, the greater their chance of developing melanoma.
However, cases of prostate, colon and breast cancer decline. Incidents of multiple sclerosis are also fewer.
The Harvard study closely follows a sharp revision in Australia of tanning recommendations.
The country's Cancer Council called for "balance" to sun exposure after years of stressing the need for cover-up and sun-block. The policy switch was made in light of research showing that vitamin D deficiency in one of the world's sunniest countries was far greater than supposed.
Responding to the Harvard study, Dr Kat Arney, of Cancer Research UK, said: "Although vitamin D is made in our bodies we actually need relatively little exposure to maintain levels."