A report published online on April 27, 2011 in the Journal of Nutrition describes protective benefits for green tea polyphenols against ultraviolet light-induced skin damage, as well as an ability to improve elasticity, density and other skin properties.
Researchers at the University of Witten-Herdecke and Heinrich Heine University in Germany assigned 60 women with light to normal ultraviolet sensitivity to receive a green tea beverage containing 1,402 milligrams per liter total catechins or a control beverage daily for twelve weeks. Before the treatment period and at six and twelve weeks, participants received a dose of irradiation to the skin from a solar simulator. Reddening, elasticity, roughness, scaling, density and water homeostasis were evaluated at these time points and blood samples were analyzed for flavonoids and other variables.
Ultraviolet-induced reddening of the skin was reduced by 16 percent after six weeks and 25 percent at 12 weeks compared to pretreatment responses among those who received green tea, indicating increased photoprotection. Skin elasticity, density, hydration, blood flow and oxygen saturation increased in those who received green tea, while roughness, volume and scaling declined. A decrease in scaling and volume and an increase in hydration were also observed in the control group; however, the degree of improvement was significantly less than that experienced by women who received green tea.
"Our green tea catechin beverage data are in accordance with the literature reporting protective effects of various polyphenols against UV-induced photo oxidation, induction of inflammation, oxidative stress, and DNA damage from different stress sources in cell cultures and animals," the authors write. "The mechanisms underlying photoprotective effects of flavonoids in humans have not been elucidated; however, they are efficient antioxidants contributing to photoprotection in plants."
"We demonstrated that ingestion of green tea catechins improved skin hydration, transepidermal water loss, density, and elasticity," they observe. "These observed skin changes were probably an outcome associated with long-term consumption of green tea polyphenols and not likely a transitory response."
Although there are many diseases that can affect the skin, the most common problems that we all have are the effects of our exposure to ultraviolet (UV) radiation from the sun over time. Having a healthy tan has, in the past, been a sign of good health. In the last 10 years, with the changes in the ozone layer in the upper atmosphere, it is clear that the effects of UV radiation from the sun are much more dangerous than originally thought.
The first preventive measure you can take is to reduce the amount of UV light that you are exposed to. This can be done either by avoiding the sun completely or more practically by wearing at least an SPF15 sunblock. One danger with using a sun block is that it tends to make people feel like they can go out in the sun more! So they end up with the same amount of UV radiation because they are simply out in the sun longer. For areas that are more exposed, such as the nose and cheekbones, a sun-blocking titanium oxide would probably be best.
Considerable interest has been generated about combining antioxidants with sunscreens to provide enhanced protection against UV rays. Two of the best-known antioxidants are vitamins C and E, both of which have been shown to be effective in different models of photodamage. In a study done on swine skin, vitamin C provided additive protection against acute UVB damage (sunburn cell formation) when combined with a UVB sunscreen. When a combination of vitamins E and C were used, very good protection from a UVB insult occurred. Vitamin C, however, was significantly better than vitamin E at protecting against a UVA-mediated phototoxic insult in this animal model (Darr et al. 1996).
It seems reasonable to avoid midday sun when possible and avoid tanning salons. Use protective clothing, hats, and umbrellas during prolonged sun exposure. Apply and reapply sunscreen or use preparations that contain micronized zinc oxide or titanium oxide for more complete protection.