Thousands of cases of breast cancer and rectal cancer can be prevented by increasing the level of consumption of vitamin D in countries with cold climates - say the results of new research. The study examined the relationship between the number of sunny days per year, the level of vitamin D in the blood and the incidence of cancer in 15 countries. The result revealed that the level of breast cancer and rectal cancer is much lower in southern latitudes. The protective effect of vitamin D to colon cancer occurs when its concentration in the blood at 22 ng / mL and for breast cancer - 32 ng / mL. As the researchers say, if people in northern latitudes have been able to make vitamin D to 55 ng / mL, the incidence of colorectal cancer could be reduced to 250 000 per year, breast cancer - 350 000. This could be achieved when a balanced diet and 10-15 minutes in the sun daily. But there is no need for sunbathing fully clothed - exposure of 40% of the skin sufficiently to produce the necessary level of vitamin.