For decades now, the public has been warned that exposure to ultraviolet (UV) radiation from the sun increases the risk of developing melanoma, the most serious type of skin cancer. But there is a problem with this generalised warning, because in America studies found that only indoor workers have increasing rates of melanoma (and the rates have been increasing since before 1940) although they get three to nine times less solar UV exposure than outdoor workers.
There are two primary types of UV rays from sunlight, the vitamin-D-producing UVB rays, and the skin-damaging UVA light. Both UVA and UVB can cause tanning and burning, although UVB does so far more rapidly. UVA, however, penetrates the skin more deeply than UVB, and may be a much more important factor in aging, wrinkles and skin cancers.
The latest studies suggest that indoor workers may have increased rates of melanoma because they’re exposed to sunlight through windows, and only UVA light, unlike UVB, can pass through window glass. At the same time, these indoor workers are missing out on exposure to the beneficial UVB rays, and have lower levels of vitamin D. So it’s the combination of exposure to UVA light and lower vitamin D levels that appear to be causing the increased rates of melanoma and the indoor workers could clearly benefit from spending some time outdoors in the sun.
Appropriate sun exposure actually helps prevent skin cancer; melanoma occurrence has been found to decrease with greater sun exposure. On the other hand it can be increased by using sunscreens which have many toxic ingredients.
It is important to realize that the sun can increase genetic damage in your skin and cause skin cancer, especially if you get regularly sunburned. But what the media and many “experts” fail to understand and explain to the public is that regular and safe exposure to sunlight allows vitamin D to be formed in your skin. The vitamin D then directly modulates genes in the skin that actually help prevent the types of abnormalities that ultraviolet light causes. Optimizing your vitamin D levels can help you to prevent as many as16 different types of cancer including pancreatic, lung, breast, ovarian, prostate, and colon cancers.
Sunscreen is not a blessing. For many years sunscreens only protected a person from the beneficial UVB rays, while letting through skin-damaging UVA light. If you do decide to use sunscreen, make sure you choose one that is non-toxic and blocks both UVA and UVB rays. Two non-toxic ingredients that scatter both UVB and the more damaging UVA rays are titanium dioxide and zinc oxide. They’ve been used all over the world for over 75 years as safe sunscreens.
When is the best time to go out in the sun? The optimal time for vitamin D production is as near to the middle of the day as possible. That would be between roughly 10:00am and 2:00pm. During this time you need the shortest exposure time to produce vitamin D because UVB rays are most intense at this time.
If you want to get out in the sun to maximize your vitamin D production, and minimize your risk of malignant melanoma, the middle of the day is the best and safest time to go. Be very careful about the length of your exposure – you only need enough exposure to have your skin turn the lightest shade of pink. This may only be a few minutes for some. Some will need less, others more. The darker your skin, the longer exposure you will need to optimize your vitamin D production.
(Info from www.dr mercola.com)