Green Tea (Camellia sinensis)
The Tonic for Chronic Disease Prevention
The roots of naturopathic medicine start with prevention. The concept alone is missing in our society, especially, when talking about healthcare. The following should persuade the individual that daily cups of green tea do more for prevention than the average multivitamin.
Tea or cha, the dried leaf of the plant Camellia sinesis, is cultivated in over thirty countries. The plant originated in China, but is now grown and consumed worldwide. Camelia sinensis is an evergreen shrub or tree that can grow up to a height of 30 feet, but is usually maintained at a height of 2-3 feet by regular pruning. The shrub is heavily branched with young hairy leaves. Parts used are the leaf bud and the two adjacent young leaves together with the stem, broken between the second and third leaves. Older leaves are considered of inferior quality and thus are of less importance medicinally.
According to Chinese legend, tea was discovered accidentally by an emperor 4,000 years ago. Since then traditional Chinese Medicine has recommended green tea for headaches, body aches and pains, digestion, depression, immune enhancement, detoxification, as an energizer, and to prolong life. The plant was also listed in The Herbal Classic of the Divine Plowman written in 100 B.C. for its medicinal properties. At present tea production in China is the second largest in the world at about 600 million lbs/year, slightly below India’s 672 million lbs. China exports only only 70 million lbs of the tea; the rest (88%) is consumed by the Chinese not as a medicinal herb but as a daily beverage.
All teas (green, black, and oolong) are derived from the same plant, Camellia sinesis. Of the total amount of tea produced and consumed in the world 78% is black, 20% is green, and less than 2% is oolong. Black tea is primarily consumed in the western countries and in some Asian countries, whereas, green tea is consumed primarily in China, Japan, India, and a few countries in North Africa and Middle East. Oolong tea production and consumption are confined to southeastern China and Taiwan. Green, black, and oolong teas undergo different manufacturing processes. The difference is in how the plucked leaves are prepared. Green tea, unlike black and oolong tea, is not fermented, so the active constituents remain unaltered in the herb. Green tea is produced by lightly steaming the freshly cut leaf, while black tea is produced by the oxidation of the leaves. During oxidation, enzymes present in the tea convert many polyphenolic therapeutic substances to compounds with much less activity. With green tea oxidation is not allowed to take place because the steaming process inactivates these enzymes. The tea leaf compromises 1 to 5% alkaloids, including caffeine, theophylline, theobromine, and xanthine. Tannic acids constitute another 9 to 21% of the leaf. The leaf also contains approximately 5 to 10% of non-vitamin substances, mainly the polyphenols. These polyphenolic compounds give green tea a variety of medical properties and is the focus of current medical research. Among the polyphenols, epigallocatechin gallate (EGCG) is the primary catechin or active ingredient.
Current research involves these polyphenols and the role they play in the prevention of chronic diseases. These chronic disease states and inflammatory conditions are a result of oxidative stress and subsequent generation of free radicals. For example, coronary artery disease resulting from LDL oxidation, renal disease and failure, several types of cancer, skin exposure damage caused by ultraviolet (A and B) rays, and diseases associated with aging. Green tea polyphenols are potent free radical scavengers due to the hydroxyl groups in their chemical structure. The hydroxyl groups can form complexes with free radicals and neutralize them, preventing the progression of the disease process. Several studies have also exhibited protection against both bacterial and viral infections. One specific study in Japan showed how a green tea preparation (30.5% EGCG) was able to positively affect intestinal dysbiosis in nursing home patients by raising levels of Lactobacilli and Bifidobacteria while lowering levels of Enterobacteriaceae, Bacteroidaceae, and eubacteria. Levels of pathogenic bacterial metabolites were also decreased. Other studies, mostly in vitro, have shown anti-microbial activity against a variety of gram-positive and gram negative pathogenic bacteria that can potentially cause cystitis, pyelonephritis, diarrhea, dental caries, pneumonia, and skin infections. The polyphenols of green tea have shown to inhibit collaginase activity of the gums to prevent periodontitis. EGCG has been shown to be a potent inhibitor of human immunodeficiency virus type 1 reverse transcriptase (HIV-1RT) and other viruses (hepatitis B, herpes simplex). EGCG also potently stimulates interleukin-1 (IL-1) and TNF production by human peripheral blood mononuclear cells. Studies are also revealing that EGCG is a potent inhibitor of gastric H+/K+ ATPase, resulting in a reduction of gastric acid secretion. Despite these promising studies regarding the medicinal benefits of green tea the majority of research concentrates on green tea’s anti-cancer activities.
In conclusion, green tea should play a huge part of an individual who seeks prophylactic care of chronic disease, especially cancer. Good quality green tea, with high polyphenol content, could prove to be one of the safest, nontoxic natural substances that can easily be incorporated into the diet. The dosage for green tea beverage varies depending on the clinical situation and desired therapeutic effect. The polyphenol content of green tea infusion is between 50-100 mg polyphenols per cup, depending on species, harvesting variables, and brewing methods. Typical dosages range from 3 to 10 cups per day. Cancer preventative effects are usually associated with 10 cups per day as seen in the Saitama Prefecture Green Tea Study in Japan. Green tea extracts can be found standardized to 80 percent total polyphenols are dosed at an average of 500-1500 mg per day.
Suneil Jain, NMD