From http://4me.style/ of 21st July 2017
Protect yourself from UV rays without blocking the synthesis of Vitamin D. This is the great challenge to which research is called. It is beyond doubt: exposure to the ultraviolet rays of the sun is one of the greatest risks for the development of skin cancers. The increase in cases of melanoma shows that we still do not protect ourselves sufficiently. In Australia, where the incidence of skin cancer is among the highest in the world, the key word to always be protected is “slip, slop, slap, wrap”.
Which means: wear a protective clothing (slip into protective clothing), spread sunscreen (slop on sunscreens), cover with a hat (slap on a protective hat), put on sunglasses (wrap on a pair of sunglasses). With this premise, I would like to remind you that the sun also produces many healthy effects essential for our body.
First of all, I say this as a dermatologist, exposure to the sun’s rays is good for the skin. We all know that the production of endorphins and a nice tan improve our mood. The immunosuppressive and anti-inflammatory action of solar radiation also produces a visible improvement of some dermatoses, including psoriasis, seborrheic dermatitis, atopic dermatitis and acne.
But where the sun is truly irreplaceable is in the production of Vitamin D. This steroid hormone (it is a “sui generis” vitamin) that has the function of regulating the metabolism of calcium and phosphorus, is produced by solar radiation in contact with the skin. Its deficiency is a cause of fragility in the bones (rickets in children and osteoporosis in the elderly) but it can also produce some types of cancer, type 1 diabetes, autoimmune diseases, hypertension and cardiovascular problems. An increasingly widespread emergency in the western world, where, incidentally, there is maximum risk awareness of UV rays. Because the portion that can be taken through food is scarcely bioavailable, 90% of the vitamin D we need to be produced by the action of the sun. But here’s the catch: the wavelengths responsible for vitamin D skin synthesis are all in the UVB range, ie they are the same that can cause erythema, sunburn and photocarcinogenesis. So how to “take the best of the sun” by avoiding exposure to the risk of a skin cancer? Michael Holick, the American dermatologist who initiated the debate on the risks of hypovitaminosis D, invites those who have Vitamin D deficiencies to expose themselves to the sun for 20% of the time necessary to burn themselves (in any case no more than 10 minutes) before applying protection solar. It is clear, however, that the solution to the dilemma is played mainly on the side of research and development of new products. We are already studying systems to measure the intensity of solar radiation that take into account the latitude, the time of day, the weather conditions and the reflectance of the ground, to be able to calibrate with greater accuracy the degree of protection necessary without preventing our skin to summarize the Vitamin D. Account to talk about it very soon.