girl tan

Sun tanning describes a darkening of the skin in a natural physiological response stimulated by exposure to ultraviolet radiation from sunshine (or a sunbed). With excess exposure to the sun, a suntanned area can also develop sunburn, and skin cancer in the long run.

Mechanism of sun tunning

Darkening of the skin is caused by an increased release of the pigment melanin into the skin’s cells after exposure to ultraviolet radiation. Melanin is produced by cells called melanocytes and protects the body from absorbing an excess of solar radiation, which can be harmful. Depending on genetics, some people can darken quickly and deeply whereas others do not darken much at all.

The ultraviolet frequencies responsible for tanning are often divided into the UVA (315 to 400nm wavelength) and UVB (280 to 315nm wavelength) ranges. UVB have higher energy than UVA waves and are therefore more damaging and more carcinogenic.

UVB

  • triggers creation and secretion of new melanin into the skin
  • is thought to cause the formation of moles and some types of skin cancer (but not melanoma)
  • causes skin aging (but at a far slower rate than UVA.)
  • stimulates the production of Vitamin D
  • is more likely to cause a sunburn than UVA as a result of overexposure, however moderate exposure can be healthy
  • is almost completely blocked by virtually all sunscreens

UVA

  • causes release of preexisting melanin from the melanocytes
  • causes the melanin to combine with oxygen (oxidize), which creates the actual tan color in the skin
  • seems to cause cancer less than UVB, but causes melanoma, a far more dangerous type of skin cancer than other types
  • is not blocked by many sunscreens but is blocked to some degree by clothing
  • is present more uniformly throughout the day, and throughout the seasons than UVB

A class issue

Intentionally darkening one’s skin did not become a socially desirable phenomenon until the mid-20th century. For centuries, sharp divisions existed in most societies between the upper classes, whose members held positions of power and leisure indoors, and the commonfolk who typically led agrarian lives toiling outside. As a result, wealthier people tended to be fairer-skinned and this correlation made pale skin more desirable. Hence, the word “fair” came to mean “beautiful”. The Industrial Revolution brought poor laborers and wealthy industrialists alike inside under the same roofs and this distinction began to evaporate. By the end of World War II, the economic boom the United States experienced gave middle class citizens more time and money to devote to leisurely pursuits. Vacations became standard practice and the advent of air travel made warmer, tropical destinations a more realistic possibility for average people. Tanned skin became associated not with a hard life of labor in the fields, but with swimming pools, backyard barbeques and dinner parties, and exotic vacations.

Veneration of fair skin is still present in the world. The geisha of Japan continue to captivate and enchant with their brilliant white painted faces, and the color white is associated with purity and divinity in many Eastern religions. In post-colonial Africa and India, dark skin is heavily associated with a lower class status, and some people resort to skin bleaching to achieve a skin color they view as more socially acceptable.

To tan or not to tan?

http://www.sephora.com/assets/browse/sun_main.jpg

Basically, there are two theories about sun tanning, with very convinced pros and cons. Let’s start with the bright side:

Health benefits

In 2002, Dr. William B. Grant published an article in the claiming that 23,800 premature deaths occur in the US annually from cancer due to insufficient UVB exposures (apparently via vitamin D deficiency).[1] This is higher than 8,800 deaths occurred from melanoma or squamous cell carcinoma, so the overall effect of sun tanning might be beneficial. Another research estimates that 50,000–63,000 individuals in the United States and 19,000 – 25,000 in the UK die prematurely from cancer annually due to insufficient vitamin D.

Another effect of vitamin D deficiency is osteomalacia, which can result in bone pain, difficulty in weight bearing and sometimes fractures. This work has been updated in Grant et al. 2005 and Grant and Garland, 2006 In addition, it was reported that in Spain, risk of non-melanoma skin cancer is balanced by reduced risk of 16 types of cancer.

Ultraviolet radiation has other medical applications, in the treatment of skin conditions such as psoriasis and vitiligo. Sunshine is informally used as a short term way to treat or hide acne, but research shows that in the long term, acne worsens with sunlight exposure and safer treatments now exist

Nothing wrong with a healthy tan

Andrew R. Ness, a researcher from the UK, wrote:

For years the medical establishment has been bombarding the public with advice to stay out of the sun, slather on sunscreen, and in general consider the sun as an enemy rather than as a friend. Fortunately, the public has been slow to accept this message and most people still like to be in the sun and consider a suntan to be a sign of good health. The original reason for the restricting sun exposure was to reduce the incidence of melanoma. Some studies had shown that a severe sunburn, especially at a young age, and intermittent exposure to strong sunlight are indeed strong risk factors for melanoma. Other studies, however, have shown that regular exposure to sunlight reduces the risk of melanoma. Melanoma is a relatively rare disease. In 1995 fewer than 1400 people died from this condition in England and Wales combined. In comparison, during the same period over 130,000 men and women died from ischemic heart disease in the same geographic area. Researchers at the University of Bristol are now sounding the warning bells. They point out that some sun exposure (without sunscreen coverage) is required in order to produce enough vitamin D to prevent rickets, osteomalacia, bone fractures, and perhaps multiple sclerosis. They also point to a recent study which found that adequate vitamin-D levels protect strongly against heart attacks. There is also considerable evidence that sunlight exposure improves mood, may combat depression, and in general creates a subjective feeling of greater wellbeing. The researchers conclude that the benefits of sunlight exposure may outweigh the widely publicised adverse effects. Says one member of the research team “Those of us who enjoy spending time in the sun can rest assured that the chance that we will be one of the people dying from our tan is small.”

British Medical Journal, Vol. 319, July 10, 1999, pp. 114-16

Now, let’s have a peek at the criticism:

There are no healthy tans

You see a ‘beautiful’ tan and your immediate thought might be that it is healthy looking, however that tanned look is actually your skin’s response to the damaging effects of ultraviolet radiation. Ultraviolet rays from the sun penetrate into the upper layers of unprotected skin, quickly damaging skin cells even before you start showing any signs of sunburn or tan. That “healthy glow” is caused by the release of enzymes by your skin’s defense mechanism, in an attempt to repair the damaged cells – basically your body’s ‘cry for help’. The intense redness of over-exposed, sunburned skin, is due to the increased blood flow caused by the release of chemicals or enzymes by the damaged skin. Over time, your body’s repair efforts may end up leading to skin cancer.

Who Gets Skin Cancer?

Skin cancer used to be considered a disease of old or middle age, but the number of cases in younger people has risen steadily due to increased exposure to the sun. Some researchers believe depletion of the atmosphere’s protective ozone layer, which allows more of the sun’s rays to hit the earth, is also responsible for the increase in cases of skin cancer. Artificial sources of UV radiation, such as sun lamps and tanning booths, can cause skin cancer as well.

People with any of the characteristics listed below are at higher risk for skin cancer and they should be particularly careful of sun exposure.

  • Fair skin. Although anyone can get skin cancer, the risk is greatest for people who have fair skin that freckles easily– a description that often includes redheads or blondes with blue or light-colored eyes. Light skin is most vulnerable because it has less melanin, the pigment that helps prevent burning.
  • Place of residence. People who live in areas that get high levels of UV radiation from the sun are more likely to get skin cancer. In the United States, for example, skin cancer is more common in Texas than in Minnesota, where the sun is not as strong.
  • Long-term exposure to UV radiation. People who work outdoors, such as farmers and construction workers, and those who go boating often, play a lot of outdoor sports, or sunbathe, are at highest risk of developing skin cancer. Keep in mind that even though most skin cancers appear after age 50, the sun’s damaging effects begin at an early age. Therefore, protection should start in childhood.
  • Sudden and intense sun exposure. People who work indoors all week and then bask in the sun for hours on end over the weekend are also at increased risk of developing melanoma.
  • Moles. Certain moles make it more likely that a person will develop melanoma. See a doctor if you have a mole with any of the following characteristics: It is asymmetrical (one half is unlike the other half); its borders are uneven or irregular; it has uneven coloring (varying shades of brown, black and pink within a single mole); its diameter is over 6 mm (the diameter of a pencil eraser). Some moles which are present at birth and often dubbed “birthmarks” are also linked to melanoma.
  • Family history. Those with close relatives who’ve had skin cancer are at greater risk of developing it themselves.
  • Diet. As early as 1939, animal studies indicated that mice fed a high-fat diet who were exposed to UV radiation developed cancer at higher rates than those on a lower fat regimen. About a decade ago, researchers at the Baylor College of Medicine in Houston, found that humans who have a high-fat diet also are at greater risk for pre-malignant tumors and skin cancers associated with UV exposure.

Other skin-protective dietary measures include eating more foods rich in antioxidants (found in a wide variety of fruits and vegetables) and selenium (in whole wheat flour, mushrooms and tuna).

  1. Exposure to x-rays. Professionals who use x-rays in their work, such as dentists and radiologists, and people who have had x-ray treatments for acne or other conditions are at increased risk for skin cancer.
  2. Exposure to certain industrial compounds. Long-term contact with coal tar, pitch, arsenic, and other industrial compounds can cause skin cancer. Strong government regulations have mostly eliminated the threat from such compounds, but arsenic may still be present in some well water.

But both sides agree in the fact that we need to protect our skin from excessive sun exposure.

Prevention

Philosophy The Healthy Tan

To avoid sunburn or excess tanning, covering up skin, wearing hats and staying out of direct sunlight is the primary defense.

If long sun exposure cannot be avoided or is desired one may use sunscreen or various over-the-counter creams to reduce sun exposure. The SPF (Sun Protection Factor) number on a sunscreen product shows its rated effectiveness. Products with a higher SPF number are those designed to provide more defense for the skin against the effects of solar radiation. However in 1998, the Annual Meeting of the American Association for the Advancement of Science reported that some sunscreens advertising UVA and UVB protection do not provide adequate safety from UVA radiation and could give sun tanners a false sense of protection.

Tanning oils or creams, when applied, are usually thicker on some parts of skin than on others. This causes some parts of skin to get more UVA and UVB than others and thus get sunburns. For this reason, improper application of tanning oils or creams may increase the occurrence of skin cancer and other skin diseases.[citation needed]

For those who choose to tan, some dermatologists recommend the following preventative measures:

  • Make sure the sunscreen blocks both UVA and UVB rays. These types of sunscreens, called broad-spectrum sunscreens, contain more active ingredients. Ideally a sunscreen should also be hypoallergenic and noncomedogenic so it doesn’t cause a rash or clog the pores, which can cause acne.
  • Sunscreen needs to be applied thickly enough to make a difference. People often do not put on enough sunscreen to get the full SPF protection. In case of uncertainty about how much product to use, or discomfort with the amount applied, switching to a sunscreen with a higher SPF may help.
  • Reapply sunscreen every 2 to 3 hours and after swimming or sweating. In direct sun, wear a sunscreen with a higher SPF (such as SPF 30). For playing sports the sunscreen should also be waterproof and sweatproof.
  • The rays of the sun are strongest between 10 a.m. and 4 p.m (see http://www.epa.gov/sunwise/actionsteps.html), so frequent shade breaks are recommended during these hours. Sun rays are stronger at higher elevations (mountains) and lower latitudes (near the equator). One way to deal with time zones, daylight savings (summer time) and latitude is to check shadow length. If a person’s shadow is shorter than their actual height, the risk of sunburn is much higher.
  • Wear a hat with a brim and anti-UV sunglasses which can provide almost 100% protection against ultraviolet radiation entering the eyes.
  • Be aware that reflective surfaces like snow and water can greatly increase the amount of UV radiation to which the skin is exposed.

The American Academy of Dermatology recommends the use of sunscreens, wearing sun protective clothing and avoiding the sun altogether.

Sources: wikipedia, the health pages

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