The Sunshine Vitamin

The body also manufactures vitamin D from cholesterol, through a process triggered by the action of sunlight on skin, hence its nickname, "the sunshine vitamin." Yet some people do not make enough vitamin D from the sun, among them, people who have a darker skin tone, who are overweight, who are older, and who cover up when they are in the sun. Correctly applied sunscreen reduces our ability to absorb vitamin D by more than 90 per cent. And not all sunlight is created equal: The sun's ultraviolet B (UVB) rays the so-called "tanning" rays, and the rays that trigger the skin to produce vitamin D are stronger near the equator and weaker at higher latitudes. So in the fall and winter, people who live at higher latitudes (in the northern U.S. and Europe, for example) can't make much of any vitamin D from the sun.