Sunshine, salt, sugar and fat all used to be categorized among the pleasures of life. Lately we are told that all are dangerous to our health, not as bad as smoking but worse than coffee or chocolate. There is a case for the other side in terms of health benefits. Each of the above—sugar, salt, and fat—is essential to life and health—but there is an optimal dose at which benefits are obvious, and a toxic dose at which illness develops. The same general interpretation applies to sunlight.
How about the good effects of sun? Not only does it keep us warm and grow our crops, it actually is the primal source of the energy of life. Sunlight is also required for vitamin D, which is actually formed by the interaction of ultraviolet light and cholesterol in the skin. At least 15 minutes a day exposure to midday summer sun is required for best results. Otherwise one must eat liver or cod liver oil regularly. Egg yolk and milk fat contain smaller amounts and all fruits and vegetables are devoid of both cholesterol and vitamin D.
Repeat: if you don't get your vitamin D by regular exposure to ultraviolet radiation from the sun, you risk deficiency of this essential nutrient. Vitamin D deficiency is common, particularly amongst those who stay indoors a lot and eat a low fat diet.
Sunbathing is a pleasurable experience, universally popular with the lucky people who get to enjoy vacation, travel and leisure activities. Fantasies of sunny outdoor scenes at the beach or in the mountains are among the most common screen memories that my patients bring up when asked to identify with pleasure. "Sun-worship" is now only a little less intense than in earlier times, such as the ancient Egyptian dynasties, when Ra, the sun god, was God.
How is it then that our medical establishment has come down so strongly against sun exposure? We are told to limit our exposure to no more than 15 minutes, and to keep indoors or wear total sun-block agents and especially to avoid the mid-day sun. Why? Because of the recent increase in skin cancer and melanoma, an increase so severe as to deserve the title, epidemic.
There are now over 600,000 new cases of skin cancer per year in the US and melanoma accounts for 30,000 new cases and 6500 deaths. Ultraviolet type B (UVB) radiation, wavelength 290 to 320 nm, has been blamed but research does not support recent exposure as the cause. Instead blistering sunburns in childhood have been associated with a double rate of melanoma in adulthood, median age of diagnosis 53 years old.
National attention has been focused on skin cancer in the 1980s because of the fact that both Presidents Reagan and Bush have had basal cell cancers removed from the face. Ultraviolet radiation damage to cell membranes and nucleic acids is a cause of this type of cancer but there are other factors as well.
Unsaturated fatty acids are normally present in our cell membranes. The electrical bonds of these molecules act as a storehouse of oxidative energy, including electrons donated by sunlight. Protection against oxidative damage to these fatty acids in the cell membrane is provided by antioxidant vitamins and enzymes, particularly carotene, vitamins C and E, and glutathione. Overdose of ultraviolet radiation can overwhelm the capacity of the cell defenses. Sunburn gives immediate evidence of this. Premature aging and the occurrence of skin cancer are more insidious and do not show up for months or years.
It is accepted as fact that ultraviolet light radiation can cause cancer. UVB the wavelength 290-320 nm is the most intense energy source and therefore most likely to cause burning and cell damage. UVA with wavelength 320-400 nm is less intense but penetrates more readily through the atmosphere year round and deeper into the skin. Thus its effect is more accumulative, about 100 times greater than UVB. It is possible that UVA is a greater hazard than UVB because it goes unrecognized, doing its damage without heat or sunburn to warn us that protection may be needed.
UVB but not UVA induces the skin to produce vitamin D, which is a protective agent AGAINST cancer. This applies not only to skin cancer but internal cancers as well. The most recent studies show an inverse relationship between sun exposure and cancer. All cancers, and especially melanoma, occur less often in persons with outdoor occupations. This is believed due to the increased vitamin D produced in the skin by sun exposure. Vitamin D not only inhibits proliferation of the skin cells, it also influences the cells (keratinocytes) to mature to the healthy, differentiated state.
Vitamin D has other health benefits, the best known of which is the absorption of calcium, essential to prevent bone weakness, called rickets in children and osteoporosis in the elderly. Sun exposure also lowers blood pressure and therefore reduces risk of stroke. A large part of the cholesterol stores of the body are in skin and a total body sunbath can activate large amounts for excretion, thus reducing blood cholesterol by as much as 15 percent! Thus, sunlight exerts a protective effect against atherosclerosis.
Sunlight increases the secretion of insulin and also the stores of glycogen in the liver, thus improving control of both diabetes and hypoglycemia. The female hormone, estrogen and to an even greater extent the male hormone, testosterone, increase after sun exposure and thus increase the pleasures of sexuality, to be sure. As body builders know, testosterone also stimulates muscle growth, a fact that was appreciated by the ancient Greeks, who held exercise classes on the beach and in the nude for training their athletes. While vitamin D production is most pronounced after exposure of the skin of the back and shoulders, the testosterone effect is almost doubled if the genital area is exposed to the sun.
Sunlight has a mood elevating effect and in some victims of seasonal depression, light exposure is the accepted treatment. The mechanism behind this is unproved but it is known that light turns off the pineal gland production of melatonin. This releases the pituitary and adrenal glands to produce their full complement of anti-stress hormones and with a stimulating effect on mood. Unlike other animals, humans require strong light to entrain the circadian rhythms and the reproductive cycle. Ordinary room light is insufficient! For the many people who are indoors all day, regular exposure to strong sunlight may offer better sleep, mood and adaptability.
Sunlight also protects against infection. In the first place sunlight actually kills germs on contact, a fact reported over 100 years ago by Drs. Downes and Blunt. Dr. Niels Finsen was awarded a Nobel Prize in 1903 for successfully treating tuberculosis of the skin with ultraviolet light. Not only does ultraviolet light kill germs, it also charges the oils in skin so they become bactericidal in themselves. Sunlight dramatically increases the oxygen content of the blood, an effect that lasts for several days after a single exposure. This contributes to the enhanced germ-killing ability of the neutrophils. Some studies found a double ability to engulf bacteria. In addition sunlight produces a significant increase in the number of lymphocytes as well as their anti-viral products, interferons.
Despite all these facts in support of the health benefits of sunlight, medical authorities have adopted a rather one-sided view, warning only of the dangers of ultraviolet exposure. The media and the advertisers have picked up this theme to such an extent that fear of sunlight is close to mass hysteria. The use of total sunblockers (SPF 15 and up) has increased dramatically. These are so effective at blocking UVB that vitamin D blood levels are reduced up to 50 percent. However UVA usually gets through and it appears that the net effect is to increase cancer risk, not only for skin but for colon and breast also. In a geographic study of total sun energy, areas with half the sunshine had a triple rate of breast cancer. In Japan, which has almost no breast cancer, the vitamin D intake is about ten-fold greater than in the US, due to their high intake of fish oils. In the US, women consume only about a quarter of the RDA—and thus depend more on sunlight for protection against cancer, osteoporosis and infection.
To be sure there are arguments against these ideas, particularly since the increase in melanoma began in advance of the widespread use of sunscreens. In my opinion, environmental pollution is the more likely cause of increased skin cancer, especially the chlorinated hydrocarbons, such as DDT, chlordane and lindane and PCBs. PCBs were banned in 1977 but are still measurable in most of us and they concentrate in skin. It is intriguing that office workers, exposed to PCB drippings from transformer coils in lighting fixtures, have more melanoma risk than do outdoor workers.
One of the most encouraging findings about the health benefits of sunlight is that by speeding up metabolism, detoxification of environmental pollutants is enhanced. Lead, mercury, fluoride, pesticides and dusts are all eliminated from double to twenty-fold more quickly after sunlight treatments.
What should one do for the best relationship to the sun? Dr. Zane Kime, in his 1980 book, Sunlight, (World Health Publications, Penryn, CA) recommends limiting first exposure to two minutes after first bathing to remove soap and cosmetic residues. I recommend the use of antioxidant nutrient-enriched tropical sun oils. Coconut oil is time tested, non-irritating and resists oxidation. Carotene is the most effective sun-protective antioxidant nutrient, even more potent than vitamin E. If you do opt for a high SPF sunblocker, PABA is the best despite the bad publicity of a few years ago. The allergic reactions turned out to be caused by impurities, not due to PABA itself. Who should use a sunblock? Those who have photosensitivity reactions, hereditary photodermatitis, polymorphic light eruption, porphyria and especially anyone with xeroderma pigmentosum, which carries a thousand-fold increased risk of cancer.
Normal skin, once adapted to sun, a process that requires one to two weeks, can protect itself and may be healthier without blocking the ultraviolet light at all—so long as the nutrient antioxidants are intact. In laboratory research, animals exposed to UVB were completely protected by vitamins C, D and E. One in four of their littermates on a regular diet got skin cancer within 6 months from the same UV exposure.
This is the most important news in personal skin care: nutrients can be applied directly to the skin to concentrate benefits in the skin. This is at least as important in preventing sunburn as controlling the dose of ultraviolet. With the right nutrient support you can relate to sunshine as a source of pleasure and health. Putting Nutrition First is the best way to healthy skin.
©2007 Richard A. Kunin, M.D.