Sunburn

Were all familiar with sunburn—the short-term skin inflammation caused by overexposure to the sun. Besides the familiar redness, pain, blistering, and flaking, overexposure to sunlight can lead to long-term skin damage, including premature aging and an increased risk of skin cancer.

The chief culprit in sunburn is not the suns heat but its ultraviolet radiation, which occurs in the forms UVA and UVB. This radiation acts on substances in our skin to form chemicals called free radicals. These free radicals appear to be partly responsible for the short-term damage of sunburn, and perhaps for long-term damage from the sun as well.

Conventional approaches to sunburn focus on prevention: staying out of the sun (especially when the sun is strongest), wearing protective clothing, and using sunscreen. Sunscreen blocks much of the radiation from our skin and helps prevent inflammation. A recent study of 1,383 Australians suggests that regular sunscreen use may also diminish the number of tumors caused by one form of skin cancer, squamous cell carcinoma.

Many drugs and herbs may increase your sensitivity to the sun. Some of the drugs that increase sun sensitivity are sulfa drugs, tetracycline, phenothiazines, and piroxicam. Herbs which might increase sensitivity to the sun include St. Johns wort and dong quai. Particular care should be taken when combining any of these substances, as they could amplify each others effects.

Principal Proposed Treatments for Sunburn:

Several studies have found that vitamins C and E, and EGCG, a bioflavonoid present in green tea, may help to prevent sunburn. Many manufacturers already add vitamin E to sunscreens. Taking these substances by mouth also appears to help.

Vitamins C and E

Antioxidants such as vitamins C and E neutralize free radicals in the blood and in other parts of our bodies. Test tube and animal studies suggest that they perform the same job in the skin. Levels of these antioxidants in skin cells decrease after exposure to ultraviolet radiation, suggesting they may be temporarily depleted.

What Is the Scientific Evidence for Vitamins C and E?

In several animal studies, vitamins C and E applied to the skin helped to protect against ultraviolet damage. One study found that topical vitamin E seemed to work best against UVB, topical C protected more against UVA, and the two vitamins together worked better than either one by itself. Vitamin E was effective even when applied to mouse skin 8 hours after ultraviolet exposure had occurred. Combining the vitamins with sunscreen yielded the best result, adding to the UV-protection offered by sunscreen alone.

In addition, preliminary evidence from a small double-blind placebo-controlled trial suggests that a face cream containing vitamin C could improve the appearance of sun-damaged skin.

Oral use of combined C and E may be beneficial as well, although more research is needed. So far the benefits appear to be milder than those of sunscreen. One double-blind study of 10 people found that 2 g of vitamin C and 1,000 IU of E taken for 8 days resulted in a modest decrease in "sunburn" induced by ultraviolet light. A 50-day placebo-controlled study of 40 people found that higher doses of these vitamins provided a sun-protection factor of about 2. (Compare this to the sun protection factor of 15 or higher in many sunscreens.) However, so far research hasnt found that these vitamins, taken separately, are any more helpful than placebo.

For more information, including dosage and safety issues, see the full articles on vitamin C and vitamin E.

EGCG

Green tea contains a potent antioxidant known as epigallocatechin gallate, or EGCG. Applied to the skin, EGCG may help to minimize sunburn damage and possibly help prevent skin cancer.

What Is the Scientific Evidence for EGCG?

According to several studies, mice given green tea to drink or receiving topical applications of green tea were protected against skin inflammation and carcinogenesis caused by exposure to UVB. Benefits were also seen in two preliminary human trials.

Dosage

A proposed dose of EGCG is 3 mg per square inch of skin.

Safety Issues

Green tea is widely consumed in many Asian countries and as a beverage or flavoring is presumably safe. No formal toxicology studies have been published on oral or topical EGCG.

Other Proposed Treatments for Sunburn:

Beta-Carotene and Mixed Carotenoids

Beta-carotene belongs to a large family of natural chemicals known as carotenoids or carotenes. Widely found in plants, carotenoids (along with another group of chemicals, the bioflavonoids) give color to fruits, vegetables, and other plants. Beta-carotene is important nutritionally because the body uses it to produce vitamin A.

Beta-carotene, alone or in combination with other carotenoids, may be able to reduce the effects of sunburn, but study results are mixed.

What Is the Scientific Evidence for Carotenoids?

In a double-blind study, 20 young women took 30 mg daily of beta-carotene or placebo for 10 weeks before a 13-day stretch of controlled sun exposure at a sea-level vacation spot.Those whod taken the beta-carotene before and during the sun exposure experienced less skin redness than those taking placebo, even when both groups used sunscreen.

Two open studies of mixed carotenoids found similar results. These trials, one of 20 and one of 22 people, found that after taking mixed carotenoids for 12 to 24 weeks, participants could tolerate more ultraviolet radiation before developing skin redness. Vitamin E (500 IU per day) taken along with beta-carotene in one of the studies didnt significantly affect the results. However, since these two studies didnt include control groups, the results are less reliable.

However, not every study has found beta-carotene or mixed carotenoids to be helpful. In a double-blind trial of 16 older women, high doses of beta-carotene taken for 23 days didnt provide any more protection than placebo against simulated sun exposure nor did high doses of mixed carotenoids protect against UVA- and UVB-induced redness in a 4-week uncontrolled study of 23 people.

Some carotenoid advocates explain these negative results by pointing at the short length of these negative trials. Carotene might simply need to be taken for longer than a month to make an impact on sunburn. However, an earlier 10-week study found that high doses of beta-carotene produced only very minor (though statistically significant) protection against sunburn among 30 men exposed to natural sunshine, compared to placebo. The study authors didnt feel this small improvement was enough to warrant using beta-carotene to prevent sunburn.

For more information, including dosage and safety issues, see the full beta-carotene article.

Other Natural Treatments

Although research information is lacking, topical jojoba, poplar bud (Populi gemma), and Aloe vera are sometimes recommended for soothing sunburn pain and itch.However, one small study found that applying aloe vera gel after UVB exposure had no effect on skin redness.