Tea is an ancient herbal drink known for its stimulant qualities largely attributed to caffeine. In modern times, it also became touted as a health food allegedly helpful in preventing or ameliorating a variety of conditions, from heart disease and cancer, to gum disease, skin aging and weight loss. The major types of tea include black, green and white (oolong), differing by the method of harvesting and processing.
Active principles in tea
The medicinal properties of tea are attributed to flavonoid phytochemicals called polyphenols. The polyphenols found in tea mainly belong to the subtype called catechins. Green tea has more catechins than black tea (about 25% vs 4%). White tea is almost as rich in catechins as green tea but is different in composition and less well studied. The main catechins in green tea include gallocatechin (GC), epigallocatechin (EGC), epicatechin (EC), and epigallocatechin gallate (EGCG).
Tea and general heath
Numerous studies have shown tea polyphenols to have protective effects against free radicals, cardiovascular damage, some cancers, infections, toxins and so forth. But there is a catch. Most of the direct studies of the green tea effects have been done in tissue culture (test tubes) and animal models. The majority of human studies have been based on statistical correlations, i.e. the researchers used statistics to link tea consumption and the incidence of various diseases. Such correlational (a.k.a. epidemiological) data is by no means proof or even strong evidence of cause and effect - although it is a useful starting point for designing clinical trials.
As of the time of this writing, the overall impression from the limited human clinical trials is that tea (especially green and white) increases antioxidant capacity of tissues, particularly the blood, and that it improves some aspects of the lipid profile, such as the level and stickiness of LDL (bad cholesterol).
The full heath benefits of tea consumption in humans, if any, may take decades to investigate beyond reasonable doubt. However, considering tea’s high safety and a large amount of indirect evidence suggestive of many potential health benefits, switching to tea (especially green or write) from other beverages makes good sense. Due to lack of direct long-tern studies, opinions vary as to how much tea should be consumed for optimal health. Most experts suggest drinking from three to ten cups per day. Those who wish to avoid caffeine or do not wish to bother with tea brewing, can take a supplement of green tea extract. A typical dosage is 100 to 150 mg three times a day of a green tea extract standardized to contain 80% total polyphenols and 50% epigallocatechin gallate. Whether the extract offers the same benefits as freshly brewed tea remains unknown.
Skin benefits of green tea
There have been a number of encouraging studies of skin benefits of green tea. Animal studies showed protection from skin cancer. Both animal and human studies have credibly demonstrated that topical green tea formulations reduce sun damage. Green tea appears to exert sun damage protection by quenching free radicals and reducing inflammation rather than by blocking UV rays. Therefore, green tea may synergistically enhance sun protection when used in addition to a sunscreen.
A small study showed benefits of 2% polyphenone (via a particular type of green tea extract) in papulopustular rosacea. In particular, a significant reduction in inflammatory lesion was reported compared to placebo.
What about wrinkles, skin sag and other signs of aging? Can green tea help? Considering their well-documented antioxidant and anti-inflammatory activities, topical green tea polyphenols are likely to slow down the development of some signs of aging. Whether green tea can actually diminish wrinkles and skin sag is far more uncertain. In a 2005 study, forty women with moderate photoaging were randomized to either a combination regimen of 10% green tea cream and 300 mg twice-daily green tea oral supplementation or a placebo regimen for 8 weeks. No significant differences in clinical grading were found between the green tea-treated and placebo groups. On the other hand, histologic grading of skin biopsies did show significant improvement in the elastic tissue content of treated specimens. More human studies are needed to not only determine the scope of anti-aging skin benefits of green tea but also to work out the optimal usage.
How to use green tea in your skin care
Some uncertainty regarding the extent of green tea benefits and its optimal usage is likely to remain for years to come. Yet, if you wish to include green tea in your skin care today, there are sensible ways to go about it.
In particular, since sun protection benefits of green tea are particularly well documented, it could make sense to apply a green tea formula under your sunscreen when venturing into the sun. It is best to combine green tea with zinc oxide-based sunscreens because zinc oxide is chemically inert and should not react with green tea (which some chemical sunscreens might do, especially in sunlight).
It may also be useful to incorporate green tea into your skin maintenance routine to possibly slow down skin aging. However, simply buying a green tea cream may not necessarily be the best way to go. Like most other antioxidants, green tea polyphenols are oxidized and lose their activity when exposed to air. Whether commercial green tea creams retain the activity is unclear and may vary widely from product to product.
If you are willing to put in a bit of extra effort, here is some alternatives. Freeze freshly brewed green tea as ice cubes and use them as a toner. (Just don’t apply ice cubes to your skin right out of the freezer, let them start thawing first or you may get a freeze burn.) Or you can make your own fresh green tea cream using standardized extract as an active ingredient . You can also drink lots of green tea or take green tea extract in capsules as discussed above - the polyphenols might reach your skin via the bloodstream in sufficient amounts to make a difference.
by mulanol.com
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