Suntan
The result of the body’s attempt at protecting itself from the damage of the sun’s ultraviolet rays. During exposure to the sun, the skin begins to produce more of the dark pigment called melanin to absorb the damaging rays. The result is a darkened skin tone. While a suntan is widely considered to be desirable, it is in fact a sign that the skin has been damaged. Melanin does provide some protection from skin damage; that is the reason dark, thick, oily skin gets fewer wrinkles than badly sun-damaged fair skin.
Even with frequent applications of SUNSCREEN, sunbathers may be at risk for developing melanoma (the most serious form of skin cancer). In fact, skin cells can undergo changes not just by exposure to the sun’s ultraviolet-B (UV-B) light (rays between 280 and 320 nanometers) but also light with longer wavelengths, including ultraviolet-A (UV-A) light.
In the past scientists had linked melanoma to damaged DNA because those who inherit a defect in their ability to repair DNA are more than 1,000 times more likely than others to get this type of cancer. Because DNA absorbs only UV-B energy, many researchers believed that only this type of light caused the damage. Others suspected UV-A light but lacked hard evidence of a link between the light and cancer.
While studying light exposure with fish susceptible to the development of melanoma, scientists at Brookhaven National Laboratory in Upton, New York, found that exposure to a wavelength of 365 nanometers (UV-A used in black lights) resulted in tumors in 38 of 85 fish tested. Of the 61 fish treated with violet light (405 nanometers), 18 developed melanoma; only one of 20 control fish kept in subdued yellow light got cancer. It is believed that melanin absorbs light, setting off a chemical reaction that produces compounds damaging to DNA.
Even with frequent applications of SUNSCREEN, sunbathers may be at risk for developing melanoma (the most serious form of skin cancer). In fact, skin cells can undergo changes not just by exposure to the sun’s ultraviolet-B (UV-B) light (rays between 280 and 320 nanometers) but also light with longer wavelengths, including ultraviolet-A (UV-A) light.
In the past scientists had linked melanoma to damaged DNA because those who inherit a defect in their ability to repair DNA are more than 1,000 times more likely than others to get this type of cancer. Because DNA absorbs only UV-B energy, many researchers believed that only this type of light caused the damage. Others suspected UV-A light but lacked hard evidence of a link between the light and cancer.
While studying light exposure with fish susceptible to the development of melanoma, scientists at Brookhaven National Laboratory in Upton, New York, found that exposure to a wavelength of 365 nanometers (UV-A used in black lights) resulted in tumors in 38 of 85 fish tested. Of the 61 fish treated with violet light (405 nanometers), 18 developed melanoma; only one of 20 control fish kept in subdued yellow light got cancer. It is believed that melanin absorbs light, setting off a chemical reaction that produces compounds damaging to DNA.
Tags: darkened skin tone, exposure to the sun, melanoma, most serious form of skin cancer, protection from skin damage, sunscreen, Suntan, sun’s ultraviolet rays
Posted in Health and Wellness
