The medical community is becoming more aware of the epidemic proportions of Vitamin D deficiency in the USA. Low Vitamin D levels are not only the cause of rickets but also cause less obvious symptoms like mood swings. It is a misconception that vitamin D comes from sun exposure. Rather, our body needs the sun to convert inactive vitamin d derived from food sources (25-dihidroxy vitamin D) into an active form (1,25 – dihidroxy vitamin D).
Excessive sun exposure has been shown to increase your risk of skin cancer, however recent evidence shows that some of the chemicals used in sunscreens also increase your risk of developing skin cancer.
What to do?
In the interest of healthy Vitamin-D levels we recommend getting a moderate amount of sun but not enough to burn your skin. The length of time you spend in the sun is entirely dependent on your skin type and where you are in the world. If you will be out in the sun for an extended period of time we recommend covering up, finding shade, and using sunscreens that are low toxicity.
The environmental working group has a list of “good” sunscreens and “bad” sunscreens: http://www.ewg.org/newsrelease/whichsunscreenssafest
Our final word on the matter is this: Sun is good, sunscreen is not so great, burning is worse.