London: Exposure to three hours of sunlight daily can practically halve breast cancer risk.
The research suggests that regular exposure to sun`s rays may have a powerful anti-cancer effect by stimulating the production of vitamin D in the skin.
Lab tests suggest that 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, the American Journal of Epidemiology reports.
Each one was quizzed on how much time they spent outdoors between April and October during four stages of life: their teens, 20s and 30s, 40s and 50s and from 60 to 74, according to the Daily Mail.
The results showed that women who had at least 21 hours a week exposure to the sun`s UV rays in their teens were 29 percent less likely to get cancer than those getting under an hour a day.
For women who spent the most time outside in their 40s and 50s, the risk fell by 26 percent 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 US research by Harvard School of Public Health, which followed nearly 119,000 adults for two decades found men who got at least 600 units of vitamin D per day were 16 percent less likely to develop heart problems or stroke than men who got less than 100 units.