Curtis James, MSc
The debate over whether sunbathing is healthy is, well, heating up
The debate over whether sunbathing is healthy is, well, heating up.
In the British Medical Journal, Bristol University researchers recently argued that the benefits from sunbathing might outweigh the risk of skin cancer. They were immediately accused of undermining years of public health campaigns that warned people to be wary of the dangers of the sun. But one of the doctors behind the article then clarified that while people should avoid excessive exposure to the sun, it should not be ignored that sunlight might help prevent vitamin D-related problems such as rickets, multiple sclerosis or even heart disease. And ultraviolet (UV) light can ameliorate depression. Certainly, rates of skin cancer are rising and sunlight plays a role in this, but at the same time, there may be some beneficial effects of exposure to sunlight.
Nature's Mood Booster
Researchers have found that exposure to natural sunlight increases the production of serotonin a chemical that stimulates the brain's pleasure centre thereby perking up our mood while warding off anxiety and clinical depression. But few people benefit from sun exposure as much as those who suffer from seasonal affective disorder or SAD, a form of depression that comes with the dark winter months. Also, one study showed that (for unknown reasons) exposure to sunlight reduced the incidence and recovery time of athletes from minor injuries.
Vitamin D Supply
Many disorders stem in part from vitamin D deficiency: breast cancer, osteoporosis, prostate cancer, psoriasis, acne and others. Humans have the ability to produce vitamin D naturally in their tissues with ultraviolet radiation as the catalyst. Ultraviolet B rays act upon fatty compounds called "sterols" to form vitamin D, which regulates the body's metabolism of calcium and phosphorus, nutrients that promote healthy bones and teeth.
Vitamin D is stored in fat cells and can remain there for months. So while Canadians cannot get enough sunlight during the winter months to produce vitamin D, they can help preserve bone strength by getting some sunlight during the rest of the year, thus creating a reserve. A few people can't digest fat adequately, which makes absorbing vitamin D a fat-soluble vitamin from the diet impossible. However, after a suntan is established, vitamin D production through the skin is stopped. To make certain you are getting enough vitamin D, take a supplement.
Reduce Your Cancer Risk
So what is the problem with sun exposure? Australians illustrate the point best. Australians think a good suntan is a sign of a healthy body and spend more time outside than people in most other countries; they also have the highest rate of skin cancer in the world. Two out of every three Australians who live to the age of 75 can expect to develop some type of skin cancer. That's twice the average risk. The reality is that a good suntan is a sign that you are being exposed to too much ultraviolet radiation.
Lip cancer from prolonged sunlight is quite common in outdoor workers. Your lips and the rest of your skin should be protected with sunscreen of SPF-15 or stronger.
But there's one problem with sunscreen. Recent studies suggest people are using sunscreens more frequently and exposing themselves more often to sun, increasing the total dose of radiation they receive.
Certain herbs and oils also make you more vulnerable. St. John's wort can promote sunburn, especially in fair-skinned people. Many essential oils (such as bergamot and geranium) can be photosensitizing when applied to the skin.
Ultraviolet light changes the behaviour of skin cells by changing the expression of genes or damaging DNA. Protective substances in cells such as "p53" can repair DNA damage, but imperfect repair leaves permanent mutations with changes in the growth characteristics of the skin. One of those changes is aging. The sun's psychological benefits should be weighed against the stresses associated with rapid skin aging.
Even if you are protected from direct sunrays, you may still be exposed to reflected UV radiation. Natural surfaces such as snow, sand, rock and water reflect sunlight, as do some metallic surfaces, especially aluminum. Remember: Exposure to solar UV radiation can still happen on cloudy or winter days.
Ultraviolet B waves disturb the body's immune system. Increased UV-B radiation could increase the severity of some infections. Furthermore, skin pigmentation (tanning) does not seem to provide much protection against the immunosuppressive effects of UV irradiation in humans.
The amount of UV-B radiation in sunlight is dependent upon the concentration of ozone molecules in the atmosphere. Unfortunately, air pollution is depleting the ozone layer.
Aside from your skin, remember your eyes. Long-term exposure to high, ambient solar radiation is associated with a 2.5-fold increased risk of cortical cataracts and a four-fold increased risk of mixed cataracts, according to a study of 2,600 residents in southern France. "These results raise the hope that simple preventive strategies, such as avoiding exposure at midday, may reduce the prevalence of cataracts," conclude the study authors in a report published by the Archives of Ophthalmology. Prolonged exposure can also damage the cornea or cause pterygia wing-shaped growths of tissue on the eye with symptoms similar to conjunctivitis. Protect your eyes with sunglasses when outdoors.
It's true: When the sun breaks through the darkened clouds, moods lift, eyes turn upward, zest for life returns and vitamin D levels are boosted. But don't overdo it, and wear protection during peak hours.
There are three main types of skin cancer. Basal cell carcinoma (BCC) is the most common but least dangerous type of skin cancer. Squamous cell carcinoma is less common but more dangerous than BCC. However, the least common but most dangerous skin cancer is melanoma. People who have a lot of moles seem to have a higher risk of developing melanoma, which can spread to internal organs and cause death if not detected and removed promptly.
Keratoses sometimes called sunspots are dry, rough, firm spots on the skin and are not skin cancers. However, they are early warning signs of excess UV radiation and very occasionally develop into skin cancer.