Malignant Melanoma: Sun, Sunscreens, and Vitamin D

Malignant melanoma is a very dangerous, often deadly form of skin cancer. Its occurrence increased most rapidly in recent years - at least amongst people with a relatively fair complexion. The increase is commonly blamed on the sun and exaggerated exposure to its light: UV radiation.

This might be true to an extent, but the whole problem is more complicated than that.

This area is subject to a lot of research. New "facts" are regularly discovered – some of them disastrously erroneous, some of them certainly right. Only time will show which is which. But some background knowledge and common sense can help you make well-founded choices about how to deal with sun in your own life. For deal with it you must; sunlight is essential. It is part of the preconditions for life on this planet, and of our lives throughout our whole evolutionary history. It is life to us, and it might be death. This is a balance on a knife's edge, and knowledge is the tool that makes us capable of keeping this sensitive balance.

This text represents current information and my interpretation of it.

Sunlight causes DNA-damage, especially oxidation of the skin and the eyes. That contributes to skin "ageing", to the development of malignant melanoma, other skin cancers, to cataract (an eye disease), and to other eye damage.

Oxidation damage is avoided by a rich intake of antioxidants and a reduced exposure to oxidants. The oxidant we are particularly interested in this time is sunlight, ultraviolet radiation. It consists of UV-A, UV-B, and UV-C. UV-C might be the most harmful, but most of it is filtered out  by the atmosphere.

UV-A radiation causes high level oxidation, and it does not cause acute sunburn. This is very dangerous, because you will not easily notice when the level is harmful, as you do with UV-B which causes burns. The tanning from UV-A is much more dangerous than the one obtained from UV-B, and the damage reaches deeper into the skin. UV-A destroys vitamin A and D.

So, UV-B causes burns and harms DNA, but under the right circumstances it can make you produce vitamin D. This is very essential. Vitamin D deficiency has been shown to be involved in the development of a large number of diseases, for instance: Alzheimer's disease, schizophrenia, asthma, cystic fibrosis, hypertension, migraines, type 1 diabetes, rheumatoid arthritis, multiple sclerosis, even tuberculosis, and possibly autism - and, of course, cancer. It is strongly indicated in all cases of malignant melanoma. This vitamin regulates thousands of different genes. Diet is often deficient of high quality vitamin D, and artificial intake can be dangerous, so sunlight is the best source.

The tendency of UV-B to cause burns is a warning system, so you notice when you reach a dangerous level of radiation and it is time to move into the shade. This might very well be the evolutionary cause of the skin's reaction.

But if sunlight causes malignant melanoma, while UV-B generates vitamin D that protects from it, why doesn't this very vitamin D neutralise the effect of UV light in this respect, so that no cancer occurs?

The answer is simple: it might do so. There is good reason to believe that under natural circumstances - vitamin D in combination with a gradually developing  pigmentation - it would. But it is human nature to try to manipulate everything, so we have a "denatured" situation. There are two points to consider here: radiation, and the preconditions for vitamin D production.

Radiation

Natural sunlight consists of both UV-A and UV-B. If you get it filtered through polluted air, glass, or clouds, UV-B is reduced or gone, while UV-A passes through. You get the damage, but no vitamin D. This is illustrated by tuberculosis, which was often cured by sunlight, but this treatment did not work anymore when they took the patients indoors so there were windows between them and the sun. They no longer got any D-vitamin!

Chemical sunblockers, or sunscreens are similar. Most of them block UV-B most efficiently, while they let UV-A pass. You are harmed but get no protection. It is worse than that: since you avoid burns you do not notice when the sunlight becomes too much for you, so you overexpose yourself to the radiation in a most dangerous way. The use of sunscreens actually increases the frequency of malignant melanoma! (This was originally written in 2010, today many sunblockers block UV-A as well.)

In addition to that, sunblockers contain chemicals which are toxic in themselves, either they are oxidants or they imitate female sex hormones (which is very dangerous). Quite frankly, despite having a very fair skin by nature and spending a lot of time in tropical or almost tropical climate, I would never touch a chemical sunblocker myself. But if you feel tempted anyway, note that the only blocking substances without any known toxicity are titanium dioxide and zinc oxide.

Production Of Vitamin D

By exposure of the skin to sunlight, vitamin D can be formed on it by fat and certain provitamins. Then it is absorbed through the skin and into the body. This is quite commonly known. But note that it is UV-B that causes this, it will not work through polluted city air, a windscreen, or a sunblocker. Then the right preconditions on the skin are required: fat and certain provitamins. If you use sun oil, you have totally destroyed this local environment, it must be your own natural skin fat. It contains everything required, applied oils do not. Actually, they just increase oxidation.

Also note that the process takes place on the skin surface. It takes some time before the vitamin is absorbed into the body. If you, for instance, bathe very soon after the exposure (within 30 minutes), you might wash off the vitamin.

Some Further Comments

Melanin, the colour pigment developing in the skin when you expose it to sunlight, protects you from damage. So take it gradually and let your body slowly become "tanned" without getting burns. Then you will be able spend more and more time in the sun without harm. On the other hand, the darker pigmentation you have, whether it is natural/permanent, or caused by sunlight, the more light you need in order to produce sufficient vitamin D.

There are some nutrients known to protect against sun-related skin damage. Carotenoids, which serve this purpose in the plant kingdom too; Nicotinic Acid, a form of vitamin B3, which accelerates the formation of melanin; and the antioxidants Selenium, vitamin C, and vitamin E. Also note that sunlight destroys vitamin A, so an extra intake is justified if you regularly expose yourself to sunlight. [Beta carotene is fine. Remember, however, that it becomes vitamin A only if the intestinal microflora is perfect, and only if it is combined with a small amount of fat.] But do not forget a general antioxidant program; it is essentially unknown which others might contribute here. I have said this before, but it deserves to be repeated: antioxidants are all interdependent, protecting different tissues and one another in a way we are not even close to understand fully yet.

Studies indicate that coffee protects against malignant melanoma. How strong a protection it offers, however, still is not sufficiently studied, but it is not insignificant.

PABA, a B-vitamin, applied externally, protects very sensitive people to some extent, even albinos, and PABA deficiency increases skin sensitivity.

While your skin will develop tan, which to some degree protects against damage; remember that some areas, if exposed, remain unprotected: eyes, lips, and nipples (of both sexes)! Males should be very restrictive in exposing their testicles to direct sunlight. They are very sensitive, and their location near the surface places them within reach for penetrating UV-light. Oxidation there might cause inheritable damage.

In the end, the best protection from sun-related damage is provided by clothes and shade. Avoid exposing naked skin to the strongest sunlight, especially at midday, unless you know you can manage it unharmed. Even if sun provides you with the healthy vitamin D, do not overdo it. Realise that too much or too strong sunlight is not good, nor is too little. Keep your exposure moderate.

Some medical drugs increase the sensitivity to sunlight, most notably antibiotics and contraceptive pills. But generally, for any regular medication, discuss the possible effect on sun-sensitivity with your doctor before you expose yourself to more than moderate sunlight

Sunbeds, or tanning beds, are linked to increased frequency of malignant melanoma. I would certainly recommend not to use any form of sunbed. The connection between its use and skin cancer is overwhelmingly obvious.

When you turn red by sunburn, you have a physical damage, and blood flow increases. More oxygen and nutrients are transported to the damaged place, and more waste and dead cells are removed in order to facilitate healing. Signs of the body's efforts to heal something are evidence of a present damage. It is always wise to heed such signs.

In order to draw your attention to the fact that you are injured, signals are sent to your brain, generating pain. Your skin becomes sensitive, it hurts if you touch it. Don't touch it then! The signal is there to show you that touching is not good. For the same reason it hurts if you expose it to more sunlight before it has healed completely. If you do, you can cause irreparable damage and you increase the risk for melanoma (skin cancer) considerably.

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Lead Image, National Cancer Institute, Public Domain.