5 Apr 2012


“Do not lie on the beach without using a sunscreen lotion with at least SPF 30.” This is common advice given by doctors. Sun Protection Factor (SPF) 30 gives a person 30 times more protection from the sun than using no lotion at all. (See Figure -11.) You may wonder why we even need to be protected from the sun. Doesn’t the light of the sun provide energy for life on Earth? Although the sun’s energy is vitally important for life on Earth, sunlight also contains ultraviolet (UV) radiation. When the highenergy waves of ultraviolet light strike cells in a person’s skin, the DNA in those cells is damaged. Mutations at specific places in the DNA can occur

This damage occurs all the time. After all, the sun is shining on us much of the time, not just when we are at the beach, but also when we walk down the street or attend a ball game. In addition, other factors, including a variety of chemicals, tobacco smoke, and X rays, can cause mutations in DNA. All of these substances, including sunlight, are referred to as mutagens.

Finally, as we have mentioned, mutations occur naturally or spontaneously in the cells of our bodies all the time. What keeps our bodies operating normally most of the time is our own built-in repair system. This system consists of a series of repair enzymes that detect damaged pieces of DNA. The damaged pieces are removed, and the DNA is repaired. The problem is that sometimes, if the exposure to the mutagen is too great, too much damage occurs. The repair enzymes are unable to fix the damage. Mutations go uncorrected. Mutations frequently produce cancers, although this disease may occur many years after exposure to the mutagen. That is the reason for using the SPF 30 lotion. Ultraviolet radiation from the sun today greatly increases the risk of skin cancer later in life. One of the three types of skin cancer, malignant melanoma, has the ability to metastasize or spread throughout the body. It can kill. A blistering sunburn early in life increases the risk of cancer years later. It is necessary to help the body protect itself by minimizing one’s exposure to mutagens.

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