Sunlight can prevent breast cancer

Newport News, Virginia United States city of Grant report, breast cancer and eating more animal fat, whereas the sun exposure on breast cancer prevention.

Grant in the 1989-1996 study in North America, South America, Asia and Europe 35 countries, food supply data, these data reflect only a country's food supply, does not reflect the different groups of food intake. Grant under the country's latitude, the sun's ultraviolet B irradiation estimated the situation.

The results show that animal food (eg meat) diet increases the high risk of breast cancer, and rich in vegetables, fruits, cereals and fish diet can reduce breast cancer risk. The reason why animal foods increase risk of breast cancer because they contain more insulin-like growth factor 1 and estrogen; vegetables contain antioxidants and phytoestrogens, which can reduce the risk of breast cancer. Alcohol can adjust the effect of estrogen on the breast. By vitamin D and fish ω-3 fatty acids reduce the risk of breast cancer.

Previous studies also found that a country's total fat intake and breast cancer incidence in the country concerned. Grant said the fat intake and breast cancer may reflect the relationship between diet high in animal foods and wine, and low plant food diet and the impact of fish.

However, Thun pointed out that the assessment of dietary factors on breast cancer is often not found in fat intake are risk factors, other studies are exploring other dietary factors other than fat role, such as the B vitamins folic acid is the role of the prevention of breast cancer, and exercise whether breast cancer prevention. American Cancer Society researchers believe that certain foods increase the risk of breast cancer, or reduce the risk of breast cancer is far from clear.

As for the role of the sun, Grant found that latitude and breast cancer, suggesting that more UV-B radiation on breast cancer prevention. UV-B can increase the synthesis of vitamin D, Grant believes that vitamin D and sun exposure preventive effects. Some studies suggest vitamin D has anti-cancer effect.

Thun noted the northeastern United States a higher incidence of breast cancer, and lower incidence of the southwest, some people think that sunlight and vitamin D role. However, Thun said: "The possible role of the sun never clear, we know that ultraviolet rays can cause skin cancer." There are other sources of vitamin D, such as fish and fortified milk. Grant reported the Nordic countries in winter higher levels of blood vitamin D, where consumption of fish may be the main source for vitamin D.