Spending an average of three hours a day exposed to sunlight can slash the risk of breast cancer by up to 50 per cent, according to research.
The research is the latest in a series of studies suggesting regular exposure to the sun’s rays may have a powerful anti-cancer effect by stimulating the production of vitamin D in the skin.
A research team from the Northern California Cancer Center, the University of Southern California, and Wake Forest University School of Medicine found that increased exposure to sunlight – which increases levels of vitamin D in the body -- may decrease the risk of advanced breast cancer. Women with high sun exposure had half the risk of developing advanced breast cancer, which is cancer that has spread beyond the breast, compared to women with low sun exposure.
“If future studies continue to show reductions in breast cancer risk associated with sun exposure, increasing vitamin D intake from diet and supplements may be the safest solution to achieve adequate levels of vitamin D,” said Gary Schwartz, Ph.D., a co-researcher from the Comprehensive Cancer Center at Wake Forest University School of Medicine.
Laboratory tests suggest breast cells are capable of converting vitamin D to a hormone that has anti-cancer properties.
Canadian researchers compared 3,101 breast cancer victims with 3,471 healthy women who had not suffered tumours.
Each one was quizzed on how much time they spent outdoors between April and October during four stages of life: their teens, twenties and thirties, forties and fifties and from 60 to 74.
The results, published in the American Journal of Epidemiology, showed that women who had at least 21 hours a week exposure to the sun’s UV rays in their teens were 29 per cent less likely to get cancer than those getting under an hour a day.
For women who spent the most time out side in their forties and fifties, the risk fell by 26 per cent and for those above 60, sunshine halved their chances of a tumour.
Meanwhile, men who get the recommended amount of vitamin D are less likely to suffer heart attacks or strokes, a study has found.
The U.S. research, which followed nearly 119,000 adults for two decades found men who got at least 600 IU of vitamin D per day were 16 per cent less likely to develop heart problems or stroke than men who got less than 100 IUD. But there was no such pattern among women, the researchers at Harvard School of Public Health found.
Both findings should be balanced in terms of burning with increased exposure to the sun, experts cautioned.