Green tea has been reported to have anti-inflammatory and anticancer properties that may be valuable as a skin treatment. The polyphenol epigallocatechin gallate (EGCG) is the predominant antioxidant in green tea. It is also the most beneficial polyphenol in green tea for cancer and anti-inflammation treatments.
Oxidation occurs when free radicals (+/– charged oxygen ions) react with molecules in our bodies and cause damage to cells. Browning fruit, rusting iron and ashes from your fireplace are all examples of oxidation. Oxidation is definitely something we want to prevent in our bodies. The paradox is that oxidation reactions that create free radicals are essential to our life. They include breathing (aerobic respiration), protein and fat metabolism and body tissue inflammatory response. Please note that free radicals are not just produced within our bodies; they are in our environment too. Pollutants, smoke, pesticides, alcohol and UV radiation in sunlight and also produce free radicals.
There really isn’t any way to avoid free radicals so we must battle them with antioxidants. Our bodies need a constant supply of antioxidants because once they pair up with free radicals they are no longer available to pair up with other free radicals. It is a permanent association and as long as we are alive we are also respiring, metabolizing and producing an endless supply of free radicals. The free radicals in our environment aren’t going anywhere either, unfortunately.
Psoriasis
Psoriasis is an autoimmune disease that is characterized by red, flaky lesions on the skin. The affected patches are made by inflammation and overproduction of skin cells. Scientists have identified a specific molecule called caspase 14 that plays an active role in determining which cells become skin cells, signaling cell death and in forming barrier cells. Psoriatic skin cells do not have caspase expression in the normal manner and skin cells increase in number exponentially which creates the characteristic lesions in Psoriasis. Hsu and colleagues have verified that human cells exhibiting signs of psoriasis do not contain caspase 14. In the same study they found that EGCG flips a “switch” that turns on caspace 14 activity so that normal skin cell growth can occur.1
The scientists set up another experiment based on the hypothesis that green tea phenols can bring about caspase14 activity. They studied molecular pathways required for EGCG-induced caspase 14 to work normally on skin cells by regulating cell differentiation and causing skin cell death. They concluded that a topical application of 0.5% green tea extracts significantly reduced the symptoms of psoriasis on the skin of mice by promoting efficient caspase 14 processing and cell number reduction in animal models. With further study and testing on human subjects, green tea extracts may prove useful to treat psoriatic skin disorders.2
Skin Aging from Sun Damage
Exposure to UV light from the sun is the cause of up to 90% of skin damage. Treatment of green tea polyphenols, most notably EGCG, to skin has been shown to regulate the biochemical pathways involved in inflammatory responses, including ultraviolet (UV) light-induced inflammatory markers of skin inflammation. The application of skin cream containing EGCG was found to prevent skin damage from sun exposure in animal models. The protective effects of green tea treatment on human skin are not well understood. Pharmaceutical and cosmetic companies touting the benefits of green tea in their skin care products are based on the results from studies on animal models, not necessarily on benefits obtained when applied to human skin.
Cosmetic Effects of Green Tea
There are many claims that green tea is the key to looking younger than you are. Many benefits that have been identified are not based on repeatable research of the anti-aging qualities of green tea because the research does not exist. Perhaps more research will be done in this area in the future, but for now research is focused on the anti-inflammatory and anticancerous benefits of green tea and the mechanisms behind them.
Of course, you can drink up to 5 cups of green tea each day and have negligible side effects, so long as you are not sensitive to caffeine or the tannins naturally occurring in tea. You can also use the skin products containing green tea or its extracts without risk of harm. Just don’t expect to take years off the age of your skin by using the skin products.
1Inhibition of autoantigen expression by (-)-epigallocatechin-3-gallate (the major constituent of green tea) in normal human cells. Hsu S, Dickinson DP, Qin H, Lapp C, Lapp D, Borke J, Walsh DS, Bollag WB, Stöppler H, Yamamoto T, Osaki T, Schuster G. J Pharmacol Exp Ther. 2005. 315(2):805-11. Epub 2005 Jul 26.
2Green tea polyphenol induces caspase 14 in epidermal keratinocytes via MAPK pathways and reduces psoriasiform lesions in the flaky skin mouse model. Hsu S, Dickinson D, Borke J, Walsh DS, Wood J, Qin H, Winger J, Pearl H, Schuster G, Bollag WB. Exp Dermatol. 2007. 16(8):678-684.
