Dr. Craig Reese, DC. PC.
3000 Center Green Dr., Suite 230
Boulder, CO 80301
303-447-1300


SUN-FRIEND OR FOE?

Sunlight is vital to every living thing on the planet. We need it to touch our skin so our bodies can make Vitamin D and that helps us absorb calcium and strengthen our bones. Ultraviolet light needs to pass through our eyes so that the pineal and pituitary glands are stimulated which helps in the production of important hormones like Serotonin and Melatonin. Yet most of us have been made afraid of the sun. For decades now, we have been warned of the dangers of sunlight and it's role in cataracts and skin cancer. We have been warned to never go outside without wearing sunglasses or sunscreen. Has this advice been helpful or harmful?

We have seen a dramatic increase in osteoporosis in the past decade, which is caused by a lack of Vitamin D and mineral absorption. Also, depression and anxiety are supposedly at epidemic levels. Prozac is one of the most prescribed drugs on the market for depression because it helps keep Serotonin in the bloodstream longer. See any connection here? Skin cancer is on the rise since the sun scare began yet the ozone layer, except over Antarctica, has not changed. As early as 1991, researchers have found a direct correlation between sunscreen use and increased incidence of skin cancer. Now what are we supposed to do?

My advice is to use your head when it comes to sun exposure. I have never thought it was a good idea to smear a chemical concoction all over your body and then go bake in the sun. Most of you remember from high school chemistry that heat helps speed up a chemical reaction. Some of the worst sunburns I have seen in the past were on people using a high SPF sunscreen but they missed a spot on their skin. Sunscreen is not a suit of armor that allows you to go in the sun endlessly for hours with no consequences. Wide hats and light cotton clothing will protect you without causing cancer. Here in the West, we have a history of people working long hours in the sun panning for gold or driving cattle across the range. But the cowboys were smart enough not to ride off into the sunset in shorts and a tank top. They wore long sleeves, pants and a hat.

The best natural protection against the sun is a tan. You should gradually get sun on your skin to increase melanin production in the skin. This is the body's defense against sun radiation. Sunlight has 3 main components: 1) infared light which are the warming rays, 2) visible light which illuminates everything and 3) ultra-violet light which are the tanning rays. UV light is further broken down into UVA, UVB and UVC. Below is a table found at http://vvv.com/healthnews/sunscreens.html

Sunscreens: Do They Cause Skin Cancer?

ULTRAVIOLET RADIATION: UVA rays constitute 90-95% of the ultraviolet light reaching the earth. They have a relatively long wavelength (320-400 nm) and are not absorbed by the ozone layer. UVA light penetrates the furthest into the skin and is involved in the initial stages of suntanning. UVA tends to suppress the immune function and is implicated in premature aging of the skin(2,13,14). UVB rays are partially absorbed by the ozone layer and have a medium wavelength (290-320 nm). They do not penetrate the skin as far as the UVA rays do and are the primary cause of sunburn. They are also responsible for most of the tissue damage which results in wrinkles and aging of the skin and are implicated in cataract formation(2). UVC rays have the shortest wavelength (below 290 nm) and are almost totally absorbed by the ozone layer. As the ozone layer thins UVC rays may begin to contribute to sunburning and premature aging of the skin(2). All forms of ultraviolet radiation are believed to contribute to the development of skin cancer(2).

Too much of anything is harmful to the body. A little bit of sun is healthy. Too much sun exposure weakens the immune system, dehydrates the body and skin and will eventually cause wrinkles, premature aging, cataracts and skin cancer. The same article referenced above has a table on skin cancer and sunscreens:

There are three major forms of skin cancer.
BASAL CELL CARCINOMA is the most common form of skin cancer. It occurs most frequently in men who spend a great deal of time outdoors and primarily produces lesions on the head and neck(2). Basal cell carcinoma rarely spreads throughout the body but can invade neighbouring bone and nerves(3).
SQUAMOUS CELL CARCINOMA is the second most common skin cancer. It primarily affects people who sunburn easily, tan poorly, and have blue eyes and red or blonde hair. Squamous cell carcinoma most commonly develops from actinic keratoses and can metastasize if left untreated. Squamous cell carcinoma of the lip is 12 times more common among men than among women(4).
MALIGNANT MELANOMA is the rarest form of skin cancer but is the most deadly. It affects the cells which produce melanin and seems to be more prevalent among city-dwellers than among people who work out-of-doors. It does not necessarily occur on sun-exposed areas of the body and is thought to be linked to brief, intense periods of sun exposure and a history of severe sunburn in childhood or adolescence. Malignant melanoma metastasizes easily and is often fatal if not caught in time(2,5).

SUNSCREENS

SUNSCREENS : Sunscreens are designed to protect against sunburn (UVB rays) and generally provide little protection against UVA rays. They come in two forms:
CHEMICAL SUNSCREENS contain chemicals such as benzophenone or oxybenzone (benzophenone-3) as the active ingredient. They prevent sunburn by absorbing the ultraviolet (UVB) rays(2).
PHYSICAL SUNSCREENS contain inert minerals such as titanium dioxide, zinc oxide, or talc and work by reflecting the ultraviolet (UVA and UVB) rays away from the skin(2).
A sunscreen with a SPF of 15 filters out approximately 94% of the UVB rays. One with a SPF of 30 filters out 97%. The SPF applies for UVB rays only. The protection provided against UVA rays in chemical sunscreens is about 10% of the UVB rating(26).

The chemical sunscreens absorb the UVB but don't really do much for the UVA. Unfortunately, it is the UVA that is responsible for Melanoma and Basal Cell Carcinoma. So these sunscreens don't really protect you from the most deadly form of skin cancer. Good old zinc oxide, on the other hand, reflects both UVA and UVB. There is also evidence that sunscreens mixed with UV light cause damage to the DNA of the skin and promotes free radical production that may cause cancer.

If you have to be in the sun for long periods my recommendations are: 1) gradually work on getting a tan without burning, 2) cover the skin with hats and light clothing, 3) cover exposed areas with zinc oxide, 4) find shade whenever possible, 5) eat lots of fruits and vegetables for their antioxidants, and 6) keep hydrated with water and minerals.

Here's another interesting fact about sunlight. Light passing through the eyes stimulates the pituitary gland to produce Melanin Stimulating Hormone (note: Melanin from the Pituitary is for skin pigment and Melatonin from the pineal gland is for sleep) which helps you tan by increasing the body's Melanin production. If you wear sunglasses all the time that you are outside you will actually burn easier because your body won't produce MSH.

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