Sunscreens 481

For overseas travelers, it is important to realize that not all SPFs are the same. In Europe the SPF is called DIN (Deutsches Institut für Normung, the company that developed the system). The DIN uses lower numbers than the American SPF system for equivalent sun protection. For example, an SPF 12 is equal to DIN 9; SPF 19 is DIN 15.

sunscreens Products that protect the skin from the harmful effects of sunlight's radiation; all sunscreen products protect against ultraviolet-B (UVB); some products protect against both ultraviolet-A (UVA) and UVB. Sunscreens are used primarily to avoid sunburn, although they can also be used to prevent the rash caused by sun sensitivity.

While some skin exposure to sunlight is necessary for the body to produce vitamin d, overexposure can have a range of harmful effects, especially in fair-skinned children. The danger is significant, since even one blistering sunburn during childhood can result in skin cancer many years later.

Most sunscreens, including those preparations containing para-aminobenzoic acid (PABA), work by absorbing ultraviolet rays of the sun. Products containing other substances (such as titanium dioxide, an uncolored relative of zinc oxide) reflect the sun's rays.

However, researchers have found that while sunscreen protects against sunburn, it may impair the ability of immune cells to fight melanoma. In one study, despite wearing sunscreen, mice exposed to ultraviolet light had a higher incidence of melanoma than did mice who were not exposed to the UV light.

Sunscreens are designed to protect against UVB light, the type of radiation that causes sunburn. Most common sunscreens are not designed to protect against UVA, another kind of ultraviolet light produced by the sun that used to be considered less dangerous because it did not directly damage skin. However, more recent research suggests that UVA can cause malignant melanoma simply because sunlight contains so much of it, and it also contributes to aging. (Think UVA-aging, UVB-burn).

Only a few sunscreens offer protection from UVA rays; those that do list the ingredient "Parsol 1789" (avobenzone), the only ingredient approved by the Food and Drug Administration (FDA) specifically for blocking the UVA rays.

Many more products that contain certain other ingredients are also allowed to claim UvA protection, but none can say how much. Since each of these chemicals block only part of the UvA spectrum, it is a good idea to choose a product with more than one of them. Check the label for some of these names: dioxybenzone, oxybenzone, sulisobenzone, methyl anthranilate, octocrylene, and octyl methoxycinnamate (also called ethyl -hexyl p-methoxycinnamate).

The best sunscreens offer a broad spectrum of protection and include such ingredients as oxyben-zone, titanium dioxide, zinc oxide, or Parsol 1789.

While sunscreens are not perfect, they can prevent a burn, which is important since studies show burns are likely to develop into skin cancer. Sunscreen can also protect against some future freckling and brown spots, and they can lower the risk of developing actinic keratoses (precancerous lesions) and skin cancer. However, the only way to completely protect yourself against skin cancer is to avoid the sun.

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