Tea and Cancer Prevention: Green, Black, Oolong, or White, Powerful Medicine in a Cup
Tea, after water, is the most popular beverage in the world. Knowing recent research on tea and cancer prevention, this is really good news. All tea comes from the same plant, Camellia sinensis, and the varieties (white, green, oolong, and black) are the result of how the leaves are processed.
There are of course many other herbal teas or infusions of plants with a history of social or medicinal use, such as chamomile or ginger, but technically these also should not be called tea, reserving that very exclusive verbal property to the hot water extract of the leaves of the shrub Camellia sinensis. So whether white tea, Chinese green tea, black tea, or oolong tea, all tea is valuable for cancer prevention, but research has demonstrated some differences in benefits.
The leaves of green tea are processed less than black tea (which is oxidized and heated), so that green tea has exceptionally high levels of antioxidants, notably one called EGCG (epigallocatechin gallate; it is a type of flavonoid). White tea is processed even less than green tea. White tea is so named because at the time of harvest, the new tea leaves are still curled up and covered with a fine white hair. All white tea is hand harvested at that early stage of growth, and is therefore more expensive than other teas. The leaves are allowed to dry naturally and minimally heated to stop oxidation. The best white teas are loose leaf rather than in bags, and the tea has a slightly sweet and pleasant flavor, and not at all “grassy” like some green teas. But if you could see and identify the flood of molecules and the complex mix of natural compounds which pours out of those leaves into your cup as they steep in the hot water, that’s when you would get really excited about tea and cancer prevention.
Volumes of research have documented the health benefits of EGCG as found in green tea. Analysis has consistently shown that white tea also provides very high levels of EGCG, and I was able to find some research literature suggesting that white tea may have even higher cancer preventing ability in laboratory experiments than green tea. Laboratory studies on tea and cancer prevention have shown that EGCG slows the growth of breast cancer cells, even cells that have become resistant to some types of chemotherapy. The cancer inhibitory effects of tea have been well studied, and are certainly due to a synergistic effect of the multiple compounds from the leaf, more than just EGCG or any single antioxidant. This is why I am certain that your best health strategy with regard to tea is to drink it as a whole food, and not to rely on extracts found in pills.
But what about prevention? When it comes to tea and cancer prevention strategies, green or white tea is on par with the best dietary strategies we have discussed so far. There is very good laboratory evidence that green tea (ECGC) can inhibit the development of breast cancer by suppressing tumor-associated fatty acid synthase. Additionally, one very interesting study, (American Journal of Clinical Nutrition, 2007) looked at the effect of combined soy protein and tea as a cancer prevention strategy (specifically preventing breast and prostate cancer).
Another point I need to make about tea before leaving this chapter has to do with the problems of convenience marketing of food products and the exploitation of health claims. Instant iced tea has virtually no catechin antioxidants, but you can be sure that the purveyors of that beverage would like to ride the coat-tails of media attention on tea and cancer prevention. If you want iced tea, brew up a pot of black or green tea, and add ice. It will still have significant antioxidant effect even though some of the antioxidant compounds adhere to the ice. And perhaps worse yet than instant tea is the new phenomenon of ready to drink tea in plastic bottles. The “green tea” which is now rivaling sodas and bottled water, being sold by the case in 16 or 20 ounce plastic bottles, is not something I would recommend. The second ingredient after water is high fructose corn syrup, which may completely negate the possible health benefits of the small amount of surviving green tea in that highly processed bottle. That spike in blood sugar will not only promote obesity, but is also promoting inflammation.In the meantime…
How to prepare a really good cup of tea
Take 1 tsp loose green tea leaves in the bottom of a glass measuring cup (Pyrex or other heat resistant), and pour 8 oz water over them that is very hot but not boiling. Use filtered water that tastes good; bad water makes bad tea. Avoid boiling water on green tea, since it “cooks” the leaves and destroys some of their delicate flavor. Let it steep for 2 minutes and not longer if you want to prevent some of the bitterness. Most of the health promoting antioxidants are already in the water after 2 minutes. You can then pour it through a strainer into your favorite tea-cup. Add to the health benefits of this experience by drinking it slowly, giving yourself some space for quiet breathing or peaceful music.
I hope this short introduction to tea and cancer prevention has convinced you to make this wonderful drink a daily habit. Perhaps we can have a cup together sometime!
to your health and wellness,
Robert Pendergrast, MD
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