I remember reading about the exceptionlly long and healthy lives that natives of the mountain regions of Pakistan and Turkey enjoy. The two common features about their lifestyles turned out to be the water they drink being thousands of times richer in its calcium content and the fact that each community spends at least 8 hours in the sun everyday. The following story in News Target explains why they live longer:
Taking a daily 10 to 15 minute walk in the sun not only clears your head, relieves stress and increases circulation – it could also cut your risk of breast cancer in half. At least that’s what Esther John, an epidemiologist at the Northern California Cancer Center, recommends. In The Breast Cancer Prevention Diet, Dr. Robert Arnot claims that national rates of breast cancer inversely correlate to solar radiation exposure. In other words, breast cancer occurs at a much higher rate in colder, cloudier northern regions than in sunnier southern regions.
How does this work? There is in fact a scientific answer. The sun stimulates production of a hormone in your skin. Vitamin D3 isn’t exactly a vitamin, but rather a type of steroid hormone that can drastically improve your immune system function. Vitamin D3 also controls cellular growth and helps you absorb calcium from your digestive tract. Most importantly, this hormone/vitamin inhibits the growth of cancer cells.
More here.