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The leaf and bud of the Camellia sinensis plant are the basis of both green and black tea. Unlike black tea, which is fermented, green tea is steamed dry immediately after harvesting, which leaves it with larger amounts of polyphenols. Its most effective polyphenol is epigallocatechin gallate (EGCG). Most of the benefits of Green Tea consumption appear to be preventive in nature.
The health benefits of Tea have become well known in recent years. Next to water, tea is the most popular beverage worldwide. Their anti-oxidant, anti-carcinogenic, anti-bacterial and lipid controlling properties have been the center of many studies over the past several years. Green Tea differs from black tea in that black tea has been through a fermenting process (Oolong varieties are semi-fermented.) While both green and black tea contain similar, complex chemical characteristics, most of the clinical studies have been performed with green tea.
Source
You can buy encapsulated extracts standardized for chemicals called polyphenols. An average dose is 200mg of an extract standardized for 25% polyphenols. You can also buy the dried herb and make tea; it is available in various grades.
Decaffeinated green tea does have the same amount of EGCG as regular green tea. Check your local health food store for decaffeinated green tea capsules. Depending on the brand, one capsule can supply as much EGCG as four cups of tea.
Green Tea is most often used by steeping in hot water, as a supplmement in capsules, or added to food products.
Function; Reasons For Use
Green Tea has demonstrated superior antioxidant properties in experimental studies than vitamin C or E. Green Tea also has the capability to increase the activity of antioxidant enzymes.
The evidence for Green Tea's potent antioxidant effects continues to accumulate. In a recent study researchers found that Green Tea compounds not only directly scavenge free radicals but also enhance the effectiveness of the body's natural antioxidant systems.
The catechin polyphenol, which works with other chemicals, increases levels of fat oxidation and thermogenesis (where the body burns fuel, such as fat, to create heat). This increase in energy expenditure is probably the mechanism causing weight loss.
Tea contains between 1 and 5% caffeine as well as other alkaloids. Caffeine is a common central nervous system stimulant found in coffee at similar or higher levels. Tea also contains flavonoids such as quercetin, rutin, etc; as well as tannins, fats, amino acids and nearly 300 other components. Current research into the anticancer polyphenols is sure to keep extracts of Green Tea in the news for years to come.
Studies indicate that green tea may help protect against cancers of the lungs, skin, liver, pancreas and stomach; it also boosts cardiovascular health and may work as a weight-loss agent by increasing fat metabolism and regulating blood sugar and insulin levels. Green tea benefits the heart by lowering cholesterol levels and reducing the tendency of blood platelets to stick together. It contains numerous cancer-fighting polyphenol compounds, including the antioxidant flavonoid catechin.
Green tea extract may promote weight loss, according to an article in the American Journal of Clinical Nutrition [1999; 70: pp.1040-5]. Green tea extract may also help dieters shed fat. Green tea is a safe alternative to traditional pharmaceuticals because its use is not accompanied by an increase in heart rate.
EGCG inhibits growth as well as the actual initiation of cancer. Green Tea shows special promise against cancer of the esophagus. Skin care products may contain EGCG.
There are significant results in scientific studies showing that daily Green Tea consumption can prevent high blood pressure. Studies have shown that several cups of Green Tea a day can substantially reduce an individual's risk for heart disease and stroke.
Reducing total cholesterol and LDL, it also increases the levels of positive cholesterol (HDL).
Green Tea can strengthen a weak immune system against common illnesses such as the flu, bronchitis or infections that take a long time to heal or return quickly. It is especially beneficial to chemotherapy patients who experience declining cell counts.
Oxygen is very important to us, but it can also be a very harmful agent in the form of active or free radical oxygen. When the active oxygen is combined with fats in our body, it is called lipid peroxide. As we get older, this lipid peroxide is more easily generated and less easily purged and tends to accumulate in our body, causing more serious diseases and also weakens the skin against infectious changes in cell tissues. Therefore, one way to slow aging may be to prevent the accumulation of active oxygen and lipid peroxide in our body. Antioxidants in Green Tea are really twenty times stronger than Vitamin E as confirmed in laboratory tests.
Fluoride in Green Tea stabilizes tooth enamel and the ECGC reduces the development of bacteria growing in the plaque. Green Tea can also kill other oral bacteria that cause bad breath. Green Tea stimulates the production of saliva and it will reduce the harmful acids formed in the mouth.
Although there is no epidemiologic data, anecdotal evidence indicates that people in countries where green tea is consumed are far less likely to have rheumatoid arthritis
People who drink Green Tea on a daily basis on average have unusually low rates of heart disease and cancer, and they also live longer.
Directions
It is not known exactly how much you need to reap the potential benefits, but four cups a day or more may be required for benefit. Do not add milk if possible, as it reduces the availability of the active flavonoid.
Side-Effects
Unlike some other antioxidants, those found in Green Tea cause no toxic side-effects.
The most worrisome chemical in green tea is caffeine, but this occurs in small amounts (an average of 20 to 30mg per cup, if brewed for two to three minutes). This is much less caffeine than in coffee.
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Green Tea can help with the following:
Green Tea can help prevent the following: | | | | | Circulation |  Hypertension | Regular and substantial consumption of green tea may provide protective effect against hypertension. |
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Environment / Toxicity |
Sun Damage/Overexposure| | Drinking four or more cups of green tea each day may help stave off skin cancer. This substance could be similarly effective if incorporated into skin care creams, but the quantity and consistency of EGCG (active compound found in green tea) should be questioned. |
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Tumors, Malignant |
 Esophageal Cancer| | Regular and substantial consumption of green tea may provide protective effect against this type of cancer. |
Cancer, General| | Green tea can delay or prevent the occurrence of some cancers, but typically must be consumed in large quantities (up to 10 cups or more) daily to achieve this effect. Extracts taken in pill form may be more convenient. |
Bladder Cancer| | Regular and substantial consumption of green tea may provide protective effect against this type of cancer. |
Colon Cancer| | Regular and substantial consumption of green tea may provide protective effect against this type of cancer. |
Pancreatic Cancer| | Regular and substantial consumption of green tea may provide protective effect against this type of cancer. |
Stomach Cancer| | Regular and substantial consumption of green tea may provide protective effect against this type of cancer. |
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KEY | | May do some good | | | Likely to help |
GLOSSARY
Alopecia
Loss of hair.
Amino Acid (Amino Acids)
An organic acid containing nitrogen chemical building blocks that aid in the production of protein in the body. Eight of the twenty-two known amino acids are considered "essential," and must be obtained from dietary sources because the body can not synthesize them.
Antioxidant (Antioxidants)
A chemical compound that slows or prevents oxygen from reacting with other compounds. Some antioxidants have been shown to have cancer-protecting potential because they neutralize free radicals. Examples include vitamins C and E, beta carotene, the minerals selenium and germanium, superoxide dismutase (SOD), coenzyme Q10, catalase, and some amino acids.
Bacteria (Bacterial, Bacterium)
Microscopic germs. Some bacteria are "harmful" and can cause disease, while other "friendly" bacteria protect the body from harmful invading organisms.
Bioflavonoid (Bioflavonoids, Flavonoid, Flavonoids)
Vitamin P. Any of a group of colored flavones (crystalline compounds) found next to the peel in many fruits. Essential for the stability and absorption of ascorbic acid.
Bronchitis
Inflammation of the mucous membrane of the bronchial tubes, frequently accompanied by cough, hypersecretion of mucus, and expectoration of sputum. Acute bronchitis is usually caused by an infectious agent and of short duration. Chronic bronchitis, generally the result of smoking, may also be known as Chronic Obstructive Pulmonary Disease (COPD) or Emphysema.
Cancer
Refers to the various types of malignant neoplasms that contain cells growing out of control and invading adjacent tissues, which may metastasize to distant tissues.
Cardiovascular
Pertaining to the heart and blood vessels.
Central Nervous System (CNS)
A collective term for the brain, spinal cord, their nerves, and the sensory end organs. More broadly, this can even include the
neurotransmitting hormones instigated by the CNS that control the chemical nervous system, the endocrine glands.
Chemotherapy
A treatment of disease by any chemicals. Used most often to refer to the chemical treatments used to combat cancer cells. Chemotherapy is usually given in cycles: a treatment period followed by a recovery period, then another treatment period, and so on. Most anticancer drugs are given by injection into a blood vessel (IV); some are given by mouth. Chemotherapy is a systemic therapy, meaning that the drugs enter the bloodstream and travel throughout the body. Usually, a patient has chemotherapy as an outpatient (at the hospital, at the doctor's office, or at home). However, depending on which drugs are given and the patient's general health, a short hospital stay may be needed.
Cholesterol
A waxy, fat-like substance manufactured in the liver and found in all tissues, it facilitates the transport and absorption of fatty acids. In foods, only animal products contain cholesterol. An excess of cholesterol in the bloodstream can contribute to the development of atherosclerosis.
Cup (Cups)
A unit of volume measurement equal to 8 fluid oz, or roughly 250ml. It also equals 1/2 pint, 1/4 quart and 1/16 gallon.
Enzymes (Enzyme)
Specific protein catalysts produced by the cells that are crucial in chemical reactions and in building up or synthesizing most compounds in the body. Each enzyme performs a specific function without itself being consumed. For example, the digestive enzyme amylase acts on carbohydrates in foods to break them down.
Esophagus (Esophageal)
Commonly called the "food pipe", it is a narrow muscular tube, about nine and a half inches long, that begins below the tongue and ends at the stomach. It consists of an outer layer of fibrous tissue, a middle layer containing smoother muscle, and an inner membrane, which contains numerous tiny glands. It has muscular sphincters at both its upper and lower ends. The upper sphincter relaxes to allow passage of swallowed food that is then propelled down the esophagus into the stomach by the wave-like peristaltic contractions of the esophageal muscles. There is no protective mucosal layer, so problems can arise when digestive acids reflux into the esophagus from the stomach.
Estrogen (Oestrogen)
One of the female sex hormones produced by the ovaries.
Free Radical (Free Radicals)
A free radical is an atom or group of atoms that has at least one unpaired electron. Because another element can easily pick up this free electron and cause a chemical reaction, these free radicals can effect dramatic and destructive changes in the body. Free radicals are activated in heated and rancid oils and by radiation in the atmosphere, among other things.
Herbs (Herb, Herbal)
Herbs may be used as dried extracts (capsules, powders, teas), glycerites (glycerine extracts), or tinctures (alcohol extracts). Unless otherwise indicated, teas should be made with one teaspoon herb per cup of hot water. Steep covered 5 to 10 minutes for leaf or flowers, and 10 to 20 minutes for roots. Tinctures may be used singly or in combination as noted. The high doses of single herbs suggested may be best taken as dried extracts (in capsules), although tinctures (60 drops four times per day) and teas (4 to 6 cups per day) may also be used.
High-Density Lipoprotein (HDL)
Also known as "good" cholesterol, HDLs are large, dense, protein-fat particles that circulate in the blood picking up already used and unused cholesterol and taking them back to the liver as part of a recycling process. Higher levels of HDLs are associated with a lower risk of cardiovascular disease because the cholesterol is cleared more readily from the blood.
Hormones (Hormone)
Chemical substances secreted by a variety of body organs that are carried by the bloodstream and usually influence cells some distance from the source of production. Hormones signal certain enzymes to perform their functions and, in this way, regulate such body functions as blood sugar levels, insulin levels, the menstrual cycle, and growth. These can be prescription, over-the-counter, synthetic or natural agents. Examples include adrenal hormones such as corticosteroids and aldosterone; glucagon, growth hormone, insulin, testosterone, estrogens, progestins, progesterone, DHEA, melatonin, and thyroid hormones such as thyroxine and calcitonin.
Hypertension
High blood pressure. Hypertension increases the risk of heart attack, stroke, and kidney failure because it adds to the workload of the heart, causing it to enlarge and, over time, to weaken; in addition, it may damage the walls of the arteries.
Immune System (Immune Response, Immunity)
A complex that protects the body from disease organisms and other foreign bodies. The system includes the humoral immune response and the cell-mediated response. The immune system also protects the body from invasion by making local barriers and inflammation. The process may involve acquired immunity (the ability to learn and remember a specific infectious agent), or innate immunity (the genetically programmed system of responses that attack, digest, remove, and initiate inflammation and tissue healing).
Insulin
A hormone secreted by the pancreas in response to elevated blood glucose levels. Insulin stimulates the liver, muscles, and fat cells to remove glucose from the blood for use or storage.
Lipid (Lipids)
Fat-soluble substances derived from animal or vegetable cells by nonpolar solvents (e.g. ether); the term can include the following types of materials: fatty acids, glycerides, phospholipids, alcohols and waxes.
Liver (Hepatic)
The largest and one of the most complex organs of the body, the liver is responsible for much of the metabolism of fats, proteins and carbohydrates. It is the site of much of the body's detoxification. It is connected very closely with digestion and the regulation of blood sugar, among many other functions. Found behind the ribs on the right side of the abdomen, it has many important functions such as removing harmful material from the blood, making enzymes and bile that help digest food, and converting food into substances needed for life and growth. Hepatic: Pertaining to the liver.
Low-Density Lipoprotein (LDL)
Also known as "bad" cholesterol, LDLs are large, dense, protein-fat particles composed of a moderate proportion of protein and a high proportion of cholesterol. Higher levels of LDLs are associated with a greater risk of cardiovascular disease.
Lung (Lungs, Pulmonary)
Organ of the body, located in the chest cavity which is designed to bring oxygen from the air into the blood stream, while also expelling carbon dioxide and other waste gases out of the body. Pulmonary: Related to the lungs.
Metabolism (Metabolic, Metabolize, Metabolizes, Metabolizing)
The chemical processes of living cells in which energy is produced in order to replace and repair tissues and maintain a healthy body. Responsible for the production of energy, biosynthesis of important substances, and degradation of various compounds. Also defined as the sum total of changes in an organism in order to achieve a balance (homeostasis): Catabolic burns up, anabolic stores and builds up; the sum of their work is metabolism.
Milligram (mg, Milligrams)
0.001 or a thousandth of a gram.
Pancreas (Pancreatic)
Opposite the liver and behind the stomach, the pancreas has two main functions - to manufacture various enzymes for digestion, and to release hormones to help control the body's use of carbohydrates. It releases insulin to help each cell absorb glucose to burn as energy. In this way, insulin controls the amount of sugar (glucose) in the blood. Proper pancreatic function is very important: too much, too little, or no insulin production can be life-threatening. Some of the chemicals released by the pancreas are not hormones, but stimulate other glands to make hormones. Once again, balance is necessary. Nutritional requirements for the pancreas are many. Research indicates that chromium vitamins C, E, B-complex, calcium, magnesium and potassium are especially important.
Peroxides (Peroxide)
Free radicals that are by-products formed in our bodies when molecules of fat react with oxygen.
Platelets (Platelet)
Cells that help the blood to clot.
Quercetin
A highly active bioflavonoid which is absorbed most effectively in combination with bromelain.
Rheumatoid Arthritis
A long-term, destructive connective tissue disease that results from the body rejecting its own tissue cells (autoimmune reaction).
Rutin
A bioflavonoid obtained from buckwheat leaves.
Saliva (Salivary)
The watery mixture of secretions from the salivary and oral mucous glands that lubricates chewed food and moistens the oral walls.
Serum
The cell-free fluid of the bloodstream. It appears in a test tube after the blood clots and is often used in expressions relating to the levels of certain compounds in the blood stream.
SHBG (Sex Hormone Binding Globulin, Sex Hormone-Binding Globulin)
A glycoprotein, synthesized in the liver, which binds testosterone and 5 alpha-dihydrotestosterone strongly, and estradiol somewhat less strongly. Circulating testosterone is mainly bound to protein - primarily SHBG, but also to albumin and cortisol-binding globulin. Since variations in the carrier protein levels may affect the concentration of testosterone in circulation, SHBG levels are commonly measured as a supplement to total testosterone determinations. The "free androgen index" (FAI), calculated as the ratio of total testosterone to SHBG, has proved to be a useful indicator of abnormal androgen status in conditions such as hirsutism.
Stomach
A hollow, muscular, J-shaped pouch located in the upper part of the abdomen to the left of the midline. The upper end (fundus) is large and dome-shaped; the area just below the fundus is called the body of the stomach. The fundus and the body are often referred to as the cardiac portion of the stomach. The lower (pyloric) portion curves downward and to the right and includes the antrum and the pylorus. The function of the stomach is to begin digestion by physically breaking down food received from the esophagus. The tissues of the stomach wall are composed of three types of muscle fibers: circular, longitudinal and oblique. These fibers create structural elasticity and contractibility, both of which are needed for digestion. The stomach mucosa contains cells which secrete hydrochloric acid and this in turn activates the other gastric enzymes pepsin and rennin. To protect itself from being destroyed by its own enzymes, the stomach’s mucous lining must constantly regenerate itself.
Stroke (Stroke-Type Event)
A sudden loss of brain function caused by a blockage or rupture of a blood vessel that supplies the brain, characterized by loss of muscular control, complete or partial loss of sensation or consciousness, dizziness, slurred speech, or other symptoms that vary with the extent and severity of the damage to the brain. The most common manifestation is some degree of paralysis, but small strokes may occur without symptoms. Usually caused by arteriosclerosis, it often results in brain damage.
Vitamin C (Ascorbic Acid)
A water-soluble antioxidant vitamin essential to the body's health. When bound to other nutrients, for example calcium, it would be referred to as "calcium ascorbate". As an antioxidant, it inhibits the formation of nitrosamines (a suspected carcinogen). Vitamin C is important for maintenance of bones, teeth, collagen and blood vessels (capillaries), enhances iron absorption and red blood cell formation, helps in the utilization of carbohydrates and synthesis of fats and proteins, aids in fighting bacterial infections, and interacts with other nutrients. It is present in citrus fruits, tomatoes, berries, potatoes and fresh, green leafy vegetables.
Vitamin E
An essential fat-soluble vitamin. As an antioxidant, helps protect cell membranes, lipoproteins, fats and vitamin A from destructive oxidation. It helps protect red blood cells and is important for the proper function of nerves and muscles. For Vitamin E only, 1mg translates to 1 IU.
Last updated: Apr 13, 2008
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