Green tea[i]
Green tea drinkers appear to have lower risk of many diseases including chronic degenerative conditions such as cardiovascular disease, cancer, stroke, oral disease, osteoporosis and infections.
Green tea is rich in flavonoids (30% by dry weight, in contrast black tea may contain only 3-10%) These include polyphenols including (epigallocatechin gallate (EGCG), which is a potent free radical scavenger. Three cups per day provide up to 320mg of polyphenols including 100 mg of EGCG.
i. Green Tea reduces death from all causes, especially Cardiovascular Disease
In one study, women who drink 5 cups or more of green tea showed 20% lower risk of dying from any cause 33% lower risk of dying from heart disease and 66% lower risk of dying from stroke, Men showed 10% lower risk of dying from any cause 20% lower risk of dying from CVD and 40% lower risk of dying from stroke. This relationship was not seen for black or oolong (fermented) teas.
A further study showed a 16% reduction in coronary artery disease and it has been suggested green tea inhibits atherosclerosis formation by lowering harmful fats in the blood. In one animal study the equivalent of 5 cups of green tea a day inhibited atherosclerosis by approximately 33% and 10 cups inhibited atherosclerosis by 50% . Green tea catechin inhibits the pro-inflammatory effects of meats , omega 6 oils (e.g. corn oil) and inhibiting blood cell clumping. Blood pressure is 50% lower in those who drank regular green tea. It has also been shown to be helpful in situation of acute heart attacks, by inhibiting heart cell damage and accelerating recovery. Similar findings have been shown in stroke situations.
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ii.Green Tea and Cancer
Women who consume the most green tea were approx 1/5th less likely to develop breast cancer independent of any other life style changes. Catechins are thought to be responsible and inhibiting formation of atherosclerosis and cancer. Catechins inhibit angiogenesis (new blood vessel formation which is essential for cancer cells to survive), but more intriguingly, Catechins cause cancerous but not normal cells to commit suicide (apoptose. Green tea has been shown to inhibit PSA (a marker for prostate cancer) rise in a dose dependent manner
The consumption of green tea plus Lycopene containing foods (e.g tomatoes, apricots, pink grapefruit, watermelon, papaya, and guava) is synergistic leading to was found to have an 80-90% reduced risk of prostate cancer. A further study showed an approx 50% reduction in advanced prostate cancer in regular green tea drinkers
Tea drinking prevents onset of ovarian cancer, by up to ¼ for one cup or so per day and up to a ½ for 2 cups. Each further cup of tea per day reduced risk of ovarian cancer by a further 20%. Even in women with established ovarian cancer drinking green tea lowered death rates by 50% over 3 years.
The combination of green tea and soy bean extract was shown to inhibit both breast cancer and prostate cancer.[ii] Combining green tea with other flavanoids (kaempferol) in broccoli and onions led to a 40% lower risk of ovarian cancer. Women consuming the flavonoid luteolin, in e.g. celery, parsley spinach. had a 34% reduced risk of ovarian cancer, compared those with the lowest luteolin intake.
Further studies suggest inhibition of Colorectal Cancer by 50% , Gallstones and Biliary Tract Cancers by a approximately a third and may offer some protection against lung cancer in smokers and inhibits spread in bladder cancers.
iii.Green Tea and Diabetes, Bone Density, Fat loss Viral infection and Exercise.
Green tea improves Insulin Sensitivity in Type 2. Green tea also protects against organ dysfunction after kidney transplant In addition it may prevent liver damage[iii] and has been shown to inhibit flu virus replication.
Green tea may significantly increase bone mineral density in Women who drank green tea 5 or more days per week even allowing for all other factors and the effects of green tea are similar to that of exercise on bone density. Loss of bone density per year was 1.6% per year in green tea drinkers compared to 4% per year in non tea drinker. Green tea seems to inhibit gum disease and protect the liver from the effects of alcohol and other toxins.
Green tea promotes fat loss. Green tea as catechins inhibits fat absorption from the blood by inhibiting some of the pancreatic and gastric enzymes involved. Long term consumption of green tea also promotes exercise endurance in animal models, in human beings this would equate to 4 cups per day
iv.Green Tea and Neural Function
EGCH in green tea protects against Cognitive Decline in a dose dependant fashion , with those consuming 2 cups per day showing ½ as much cognitive decline, Alzheimer's Disease and Parkinson's. The postulated mechanisms include scavenging of free radicals and activation of survival genes as well reduced formation of Beta amyloid protein which is seen in plaques Sin Alzheimer's disease. [iv]
One set of authors wrote
“The potential effect of tea drinking in protecting against the cognitive decline of advanced age thus has great significance, given the rapid aging of the population and the rising prevalence of vascular and Alzheimer-type dementia….,"
the study authors conclude…
"Because tea is cheap, nontoxic, and widely consumed, it has a huge potential effect in promoting cognitive health and perhaps delaying the onset of dementia. Further studies should investigate whether tea consumption lessens the risk of vascular and Alzheimer-type dementia”."[v]
One of the green teas that has been shown to have the highest levels of EGCG is “Long Jing” or otherwise known as “Dragon Well”.
See www.HealingThePerson.com for details.
[i] Much of the information was adapted from the excellent article at http://www.whfoods.com/genpage.php?tname=foodspice&dbid=146#healthbenefits
References quoted Adhami et al H. Oral consumption of green tea polyphenols inhibits insulin-like growth factor-I-induced signaling in an autochthonous mouse model of prostate cancer. Cancer Res. 2004 Dec 1;64(23):8715-22. Aneja R, et al Epigallocatechin, a green tea polyphenol, attenuates myocardial ischemia reperfusion injury in rats. Mol Med. 2004 Jan-Jun;10(1-6):55-62. Azam Prooxidant property of green tea polyphenols epicatechin and epigallocatechin-3-gallate: implications for anticancer properties. Toxicol In Vitro. 2004 Oct;18(5):555-61. Baek Epicatechin gallate-induced expression of NAG-1 is associated with growth inhibition and apoptosis in colon cancer cells. Carcinogenesis. 2004 Aug 12 Bastianetto S, Neuroprotective effects of green and black teas and their catechin gallate esters against beta-amyloid-induced toxicity. Eur J Neurosci. 2006 Jan;23(1):55-64. BBC Health News. Green tea 'may protect the heart. 2005/02/28, http://news.bbc.co.uk/go/pr/fr/-/1/hi/health/4298403.stm. Chen D Green tea and tea polyphenols in cancer prevention. Front Biosci. 2004 Sep 01;9:2618-31. PMID:15358585. Chen JH, Green tea polyphenols prevent toxin-induced hepatotoxicity in mice by down-regulating inducible nitric oxide-derived prooxidants. Am J Clin Nutr. 2004 Sep;80(3):742-51. Choi YB, Protective effect of epigallocatechin gallate on brain damage after transient middle cerebral artery occlusion in rats. Brain Res. 2004 Sep 3;1019(1-2):47-54. Chow Modulation of human glutathione s-transferases by polyphenon e intervention. Cancer Epidemiol Biomarkers Prev. 2007 Aug;16(8):1662-6.
[ii] Zhou et al. Combined inhibition of estrogen sensitive dependant human breast carcinoma by soy and tea bioactive components in mice. And Zhou et al. Soy phytochemical and tea bioactive components synergistically inhibit androgen sensitive human prostate cancers Journal of Nutrition. 2003;133:516-21
[iii] American Society for Nutrition J. Nutr. 138:323-331, February 2008 Green Tea Extract Protects Leptin-Deficient, Spontaneously Obese Mice from Hepatic Steatosis and Injury Bruno et al
[iv] Am J Clin Nutr. 2008;88:224-231.
[v] http://www.medscape.com/viewarticle/577461?src=mp&spon=17&uac=83420PY
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