Over the past decade a great deal of research has been published about the benefits of green tea.
It seems that those populations that have the highest consumption of green (and black) tea have the lowest risks of a variety of cancers.
Some studies, from Japan, have shown that tea consumption can both delay cancer onset and prevent recurrence. Some of these include Esophageal and Stomach, Lung and Respiratory tract, Skin, Breast and Prostate Cancer.
The "active" ingredients in green and black tea are epigallocatechins, epicatechins, theaflavins and polyphenols. These are excellent antioxidants, based on specific research and also confer significant cardiovascular protection and benefit.
The majority of the data recommends at least 3 to 5 cups of tea daily; this is where the benefit begins. Those who had 5 to 10 cups per day had the highest levels of protection, and the lowest rates of cancer.
Dr. Chris Calapai
When we think of all of the beverages that people drink , daily, and look at the lack of benefit and the potential downside or side effects, it is extremely wise to consider switching to green and black tea.
An excellent source of green tea as well as a variety of other antioxidants and healthy vegetable components is found in a green food supplement called Genesis.
Click here to look at the ingredients in Genesis.
Mechanistic Findings of Green Tea as Cancer Preventive for Humans
Based on our initial work with green tea, in which repeated topical applications of (−)-epigallocatechin gallate (EGCG), the main green tea polyphenol, inhibited tumor promotion in a two-stage carcinogenesis experiment on mouse skin (Phytother Res 1, 44–47, 1987), numerous scientists have since provided so much additional evidence of the benefits of drinking green tea that it is now an acknowledged cancer preventive in Japan, and will possibly soon be recognized as such in other countries.
Our work has so far produced several important results with EGCG and green tea: a wide range of target organs in animal experiments for cancer prevention, wide bioavailability of 3H-EGCG in various organs of mice, delayed cancer onset of patients with a history of consuming over 10 cups of green tea per day, and absence of any severe adverse effects among volunteers who took 15 green tea tablets per day (2.25 g green tea extracts, 337.5 mg EGCG, and 135 mg caffeine) for 6 months.
This paper introduces three new findings: 1) EGCG interacted with the phospholipid bilayer membrane resulting in confirmation of the sealing effect of EGCG; 2) EGCG inhibited TNF-α gene expression in the cells and TNF-α release from the cells; 3) high consumption of green tea was closely associated with decreased numbers of axillary lymph node metastases among premenopausal Stage I and II breast cancer patients, and with increased expression of progesterone and estrogen receptors among postmenopausal ones.
These results provide new insights into our understanding of the mechanisms of action of tea polyphenols and green tea extract as a cancer preventive.
Theaflavins in Black Tea and Catechins in Green Tea Are Equally Effective Antioxidants
Green tea catechins, including (-)-epicatechin (EC), (-)-epicatechin gallate(ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate(EGCG), are oxidized and dimerized during the manufacture of blacktea and oolong tea to form orange-red pigments, theaflavins (TF),a mixture of theaflavin (TF1), theaflavin-3-gallate (TF2A),theaflavin-3′-gallate (TF2B) and theaflavin-3,3′-digallate (TF3).
The present study was designed to compare the antioxidant activitiesof individual TF with that of each catechin using human LDLoxidation as a model. All catechins and TF tested inhibitedCu+2-mediated LDL oxidation. Analysis of the thiobarbituricacid–reactive substances (TBARS) and conjugated dienesproduced during LDL oxidation revealed that the antioxidantactivity was in the order: TF3 > ECG > EGCG =" type="#_x0000_t75">TF2B =" type="#_x0000_t75">TF2A >TF1 =" type="#_x0000_t75">EC > EGC. Four TF derivatives also demonstrated a dose-dependentantioxidant activity in Cu+2-mediated LDL oxidation at concentrationsof 5–40 µmol/L.
These results demonstrate that theTF present in black tea possess at least the same antioxidantpotency as catechins present in green tea, and that the conversionof catechins to TF during fermentation in making black tea doesnot alter significantly their free radical–scavengingactivity.
Preventive effects of drinking green tea on cancer and cardiovascular disease: Epidemiological evidence for multiple targeting prevention
The significance of drinking green tea in prevention of two of the main lifestyle-related diseases, cancer and cardiovascular disease, was demonstrated in terms of a prospective cohort study on a total of 8,552 general residents in Saitama Prefecture, Japan.
On the basis of the follow-up study, we revealed decreased relative risk of cancer incidence for those consuming over 10 cups a day, compared with those consuming below 3 cups: 0.54 (95% men, 0.57 (0.34–0.98) for women, and 0.59 (0.35–0.98) for both sexes. Furthermore, a significant delay in cancer onset was associated with increased consumption of green tea.
Next, decreased relative risk of death from cardiovascular disease was 0.58 (0.34–0.99) for men, 0.82 (0.49–1.38) for women, and 0.72 (0.60–1.04) for members of both sexes consuming over 10 cups a day. Finally, we evaluated the life-prolonging effects of drinking green tea on cumulative survival, using the life table.
Green tea: Health benefits as cancer preventive for humans
Green tea is an acknowledged cancer preventive in Japan. The aim of this review article is to develop the concept of cancer prevention with green tea beverage for humans, which has largely been our exclusive research territory.
This paper briefly reviews several topics, beginning with the introduction of our initial work on penta-O-galloyl- -D-glucose and (-)-epigallocatechin gallate (EGCG), the main constituent of green tea extract. The mechanisms of EGCG action, particularly the reduction of TNF- are discussed, and we show how use of 3H-EGCG revealed a wide range of target organs for cancer prevention. The results of an epidemiological study in Saitama Prefecture allowed us to determine the cancer preventive amount of green tea – 10 Japanese-size cups per day, about 2.5 g green tea extract – which made it possible for us to introduce the two-stage strategy of cancer prevention with green tea. The first stage is the delay of cancer onset for the general population.
The second stage is the prevention of recurrence of cancer for patients following cancer treatment. Combination cancer prevention with green tea and cancer preventive drugs is proving especially beneficial for Japanese, who drink green tea every day. And finally, the stimulating comments of Prof. Jim Watson have encouraged green tea scientists.