Green tea is getting a ton of attention these days as medical research is finally catching up to naturopathic/alternative medicine. Due to the frequent lack of convincing research in alternative medicine, many potentially health-promoting or disease-fighting nutritional supplements are dismissed as viable options for treatment or prevention in mainstream clinical practice. This unfortunate, as many currently available therapies (i.e.drugs) are synthetic small-molecule compounds which are often associated with a number of adverse or potentially lethal effects. In an effort to treat or cure a disease we are affecting a number of other important biochemical processes to our detriment. It would seem that naturally derived products have the greatest potential in the prevention of disease, to use “food as a drug” as nature has most likely intended. Times are changing however, as modern science is proving more and more that treatments previously passed off as “snake oil” are actually powerful health promoting and disease-preventing agents.
Consumed for thousands of years as part of traditional Chinese medicine, green tea was to consider a health-promoting beverage. Traditional Chinese medicine has recommended green tea for headaches, aches and pains, depression, as an energy-promoting agent, detoxification, and in general to promote a long, healthful life. Once again, current medical research is beginning to catch up with ancient medical practice, as green tea is proving to be beneficial to health and fitness in a number of unexpected ways. It seems that the ancient Chinese medicine assertion that green tea “promotes health” is not far off from what researchers are beginning to uncover. Recent human research studies have suggested green tea may have the following beneficial effects:
- Reduction in the risk for cardiovascular disease
- Reduction in the risk for certain types of cancer
- Promotion of oral health
- Bodyweight control and improvements in body composition
- Antibacterial and antiviral activity
- Protection from harmful UV rays
- Associated with increases in bone mineral density
- protection form neruodegenerative diseases
The chemical composition of green tea is extremely complex, the potentially health-promoting compounds including the amino acids teanine, 5-Nethylglutamine, glutamic acid, tryptophan, glycine, serine, aspartic acid, tyrosine, valine, leucine, threonine, arginine, lysine, polyphenols, carbohydrates such as fructose, glucose, and fructose, lipids including EFAs, various plant sterols (hormone-like compounds present in plants), caffeine and theophylline, pigments such as chlorophyll and carotenoids, and trace-minerals such as calcium, magnesium, chromium, manganese , iron, copper, zinc, selenium, among others. It is likely that with the health-promoting and disease-preventing effects of green tea, as with many other natural products, the sum is greater than the whole. All the constituents of green tea likely act in a synergistic manner, at the right time and at the right place (biochemically speaking), just as nature intended. Read on to find out what we know about green tea and how it can benefit your health.
Antioxidant activity
The polyphenols present in green have generated lots of interest by researchers, as polyphenols, a large class of compounds found in plants, are antioxidants which have been associated with decreased risk of a number of diseases. The particular array of polyphenols in green tea has been shown to have extremely potent antioxidant activity, most likely associated with the reduction in cancer risk and cardiovascular disease. One of the particular polyphenol compounds in green tea, a catechin called epigallocatechin gallate (EGCG) has been shown to be a powerful antioxidant in addition to having potent anticarcinogenic and anti-lipogenic activity. Also present in green tea are carotenoids, tocopherols, ascorbic acid (vitamin C), and minerals such as Cr, Mn, Se or Zn. Important anti-oxidants in their own right, it is likely that the presence of these non-phenolic antioxidants can actually support the anti-oxidant activity of the polyphenols in green tea, acting in a synergistic manner. Extensive research has on the antioxidant effects of green tea has shown that when combined with a balanced diet, the consumption of green tea on a daily basis can protect against oxidative damage so intimately associated with aging and disease.
Energy-promoting/fat burning effects
Green has been associated for some time with fat loss and improvements in body composition, most like attributed to the caffeine and theophylline content. Contrary to the any anti-caffeine propaganda you may have encountered, caffeine has been shown time and time again to promote lipolysis (i.e fat burning). Theophylline acts synergistically with caffeine to promote its effects, and additionally opens up the airway (theophylline was often prescribed as an asthma treatment years ago). While the caffeine and theophylline are certainly involved in the fat-burning ability of green tea, there are other mechanisms by which green tea encourages fat loss and decreased body fat storage. In vitro studies using both mouse and human preadipocytes (basically “precursor” fat cells) have shown that the EGCG in green tea not only inhibits adipogenesis (differentiation to a mature fat cell), but also causes the fat cells to die! While in-vitro studies rarely correlate nicely with in vivo effects, many studies have shown that in humans, green tea promotes body fat loss and thermogenesis by mechanisms independent of those attributed to its caffeine and theophylline content; most likely involving the catechin EGCG. It is likely that the combination of caffeine, theophylline, and EGCG act in a synergistic manner to induce weight loss and fat-burning. While there is no definitive amount of green tea needed to induce its weight loss and fat burning effects, EGCG has been shown to accumulate over time and we already know the half-lives of caffeine and theophylline. A good recommendation for the amount of green tea needed to elicit weight loss and all of the other reported benefits would be 2-3 6-ounce servings/day.
Anti-carcinogenic effects
While there are certain genetic mutations that can pre-dispose or even guarantee that a person with get a certain type of cancer in their life-time, cancer is mostly associated with lifestyle and aging. If a person lives an unhealthy lifestyle associated with lack of exercise and a poor diet, there is a much higher incidence of cancer. It seems that there is strong link between oxidative damage and cellular aging, with greater oxidative damage occurring in the context of an unhealthy lifestyle. A new approach in cancer prevention research is to find dietary components that are capable of slowing cellular aging and carcinogenesis without affecting the normal growth of healthy cells. Countless in-vitro, animal studies, and epidemiological studies in humans have shown that green tea has a strong anticarcinogenic effect, both in the prevention of cancer in the first place and the inhibition or cancer cell growth and proliferation. This evidence has been so convincing that the National Cancer Institute has initiated a plan to utilize agents found in tea to develop chemo-preventative agents in human clinical trials. It seems that the cancer-inhibiting activity of green tea may extend far beyond it anti-oxidant activity, as green tea has also been impacted in the activation of detoxifying enzymes, an anti-inflammatory effect, and it seems that one or a number of components may directly inhibit cancer cell growth possibly even initiate apoptosis (programmed cell death, an abnormal cell will usually “commit suicide” to avoid becoming cancerous- cancer has the acquired ability to avoid this process, allowing it to proliferate)
Cardiovascular disease risk
Ancient Chinese medicine has used green tea extensively for its blood-pressure reducing effects and decreased risk of cardiovascular disease. While the mechanism behind these effects is not currently understood, they are most likely associated with the polyphenol-induced antioxidant and anti-inflammatory effects of green tea. Animal studies have shown that green tea polyphenols, particularly EGCG, are associated with a decrease in LDL (bad cholesterol) and total cholesterol levels. Any agent that acts to raise the HDL to LDL ratio is cardio-protective, preventing the formation of atherosclerotic lesions (buildup of plaque in the arteries which eventually causes blockage resulting in stroke or heart attack). Uncontrolled oxidation is also associated with atherosclerosis; it seems that the polyphenols found in green tea promote cardiovascular health through a number of mechanisms. We have yet to show many of these mechanisms at work in humans, but epidemiological studies have shown time and time again that green tea show similar cardio-protective effects in humans to those seen in animals.
Summing it up...
Green tea has been shown to have a wide variety of significant health-promoting effects in humans, animals, and in vitro cell culture. The polyphenols present in green tea, particularly the catechin EGCG, have been shown to have anti-oxidant and anti-carcinogenic properties in addition to preventing cardiovascular disease and promoting weight loss. It is no mystery that health and fitness are two intimately related concepts; with greater fitness comes greater health and vice-versa. Anything we can do, whether it is through exercise, weight loss, diet, or supplement intake, to influence either of these will be sure to promote a long, healthy life. Pharmaceuticals, although necessary, are not without their problems. If diseases could be prevented before dangerous pharmaceuticals are needed to treat them, the collective health of our society would increase exponentially. We may never be able to cure certain diseases with our current approaches; until we refine our techniques so that viable cures can be discovered with approaches such as gene therapy, the “cure” lies in prevention, not treatment of disease. With natural, health-promoting agents in addition to a healthy diet and exercise program we can conceivably prevent diseases such as cancer, diabetes, and cardiovascular disease before they occur. You cannot have fitness without health, and green tea has been shown to increase fitness and health at the same time. With all of the proven benefits, there lacks any good reason not to include green tea as a supplement in your diet and nutrition program; 2-3 6-ounce servings per day should be sufficient to reap all of its benefits for health and fitness.
