Health Benefits of Green Tea
About Green Tea
Latin Name: Camellia sinensis
Tea has been consumed for over 4,000 years. Though tea originated in India and China, green tea consumption took root in China first. Most cultures around the world consume tea as a beverage in some form or the other. Milk may or may not be used to prepare tea.
There are 3 main varieties of tea: black, oolong, and green. The essential difference in all these teas is in their processing method. Green tea is the least processed and therefore contains the highest concentrations of polphenols: the catechins.
Tea plants grown on a higher altitude have a richer flavor as the leaves mature slower. Tea plants remain commercially productive for almost 100 years.
Nutrients in Green Tea
Tea contains various catechin polyphenols of which epigallocatechin-3-gallate (EGCG) is the most abundant and the most beneficial.
Green tea also contains phytochemicals, carotenoids, tocopherols, vitamins C, A, K, and many of the B-complex vitamins. It also contains chromium, manganese, selenium, zinc, potassium, and magnesium. Green tea is free of calories.
Green tea also contains caffeine (theine), tannin (flavonols), theophylline, theobromine, and saponins. In fact, green tea contains over 450 organic compounds.
Health Benefits of Green Tea
One cup of green tea provides 80-105 mg of polyphenols, while it provides 20-35 mg of EGCG.
Many studies have been conducted on the benefits of green tea. It has been found that those who drink green tea regularly have a lower risk of certain conditions, infections, and diseases.
Green Tea and Cholesterol
Green tea lowers LDL cholesterol, raises HDL cholesterol, and lowers total cholesterol. The polyphenols in green tea not only prevent the intestinal absorption of cholesterol but also help in removal of cholesterol.
Green Tea and Weight Loss
Those who drink tea with the aim to lose eight will be glad to learn that green tea aids in weight loss. In fact, it helps burn fat by boosting the metabolism. The catechins, caffeine, and theanine in green tea do just that.
Interestingly, green tea acts to effect the fat loss from the abdomen and viscera. A study published in the American Journal of Clinical Nutrition, January 2005 issue, indicates that green tea lowers body fat, waist measurements, and helps in reducing weight.
Green Tea and Cancer
The catechin polyphenols, especially EGCG, in green tea may play a role in cancer prevention as they kill the cancer cells. Green tea may reduce the risk of a variety of cancers like those of the ovary, prostrate, prostrate, colon, rectum, lungs, bladder, breast, oesophagus, pancreas, stomach, and skin.
Green tea also helps in shrinking malignant brain tumors in affected children.
Research at the University of Strathclyde, in Glasgow, Scotland, points toward this as reported in the Huffpost, Canada (see sources below).
Green tea helps in protecting against cancer. The October 2004 issue of the journal of Pharmacy and Pharmacology reports that green tea polyphenols improve the efficacy of cancer drugs while the August 2004 issue of Cancer Letters reports that green tea reduces the negative side effects of cancer drugs.
Green Tea and the Heart
Green tea reduces risk of heart disease as it lowers cholesterol and triglycerides. High cholesterol and triglycerides are indicted in atherosclerosis. Consumption of 3 cups of green tea a day cuts down the risk of heart attacks by as much as 11%.
Drinking 5 cups of green tea also lowered the risk of death from chronic vascular disease and stroke by 23%-62% in women and by 12%-42% in men. Women interestingly were better protected. A study in Japan published this report in the September 2006 issue of JAMA.
The catechins in green tea make the blood thin thus preventing formation of blood clots and thereby reducing the risk of strokes. EGCG also protects the heart muscle from damage in those with acute coronary artery disease.
Green tea also helps in faster recovery after a stroke or heart attack as it reduces heart cell death. It also protects the brain cells and reduces brain damage following a stroke.
Therefore daily intake of green tea is very beneficial for the heart and brain.
Studies also indicate that green tea lowers high blood pressure by as much as 65% in those who drank more than 2-1/2 cups of green tea daily.
Green Tea and Diabetes
As reported in the August 2004 issue of BMC Pharmocology, green tea increases the ability of the body to better utilize blood sugar. Also, EGCG improves insulin sensitivity in those with type 2 diabetes.
Green Tea and Liver disease
The metabolism of alcohol produces free radicals that damage the liver if they are cannot be countered by the antioxidants in the liver. Green tea catechins, in particular EGCG, protects liver against the damaging free radicals. Thus green tea can be taken not only to protect but also treat liver disease as research suggests.
Green Tea and Immunity
Green tea raises the number of T cells in the body, which are necessary for proper immunity development as research from Linus Pauling Institute at Oregon State University indicates. This study was published in the journal Immunology Letters.
Green Tea and Rheumatoid Arthritis
The catechin EGCG in green tea is shown to reduce inflammation and joint damage in Rheumatoid Arthritis, as research by scientists from the University of Michigan Medical School shows.
EGCG reduces the production of inflammatory chemicals and in higher doses halts their production, the research shows.
Green Tea for Digestion
The catechin EGCG in green tea along with other polyphenols counter the bacteria and virus present in the digstive tract, reduce inflammation, and swelling in the stomach.
Green Tea and Kidney Disease
Green tea helps in controlling the production of free radicals by certain immunosuppresant drugs that are needed to be given after an organ transplant.
Other parameters of kidney function like serum creatinine, uric acid, blood urea nitrogen, and urinary excretion of glucose were also bettered.
These were shown in an animal study published in January 2005 issue of Pharmacological Research.
Green Tea and Bone Density
The catechins in green tea increase bone density as a study by researchers at the University of Tokyo has shown.
Green tea makes bones and teeth healthy, thus effectively preventing osteoporosis and peridontal disease. The catechins prevent the bacteria responsible for gum disease from producing toxic products that destroy bones.
Green Tea and Endurance
Green tea increases endurance in studies on lab rats. It is to be noted however that a single dose before exercise is not effective. Green tea had to be taken daily over a period of weeks to get the benefit of increased endurance.
It is estimated that about 4 cups of green tea should be taken everyday by athletes wanting to get the same levels of endurance benefits as observed in these test animals.
Green Tea and Neurodegenerative Diseases
Neurodegenerative diseases cause death of brain cells mainly due to over production of free radicals due to various causes.
The catechins in green tea protect against the degenerative changes in the nerves and subsequent reduction in damage and death of brain cells.
The main causes of brain damage are the accumulation of iron in particular areas of the brain and damage to the brain cells and damage to the brain cells by the free radicals. These 2 factors have been found to be the causes of Parkinson's, Alzheimer's, cognitive decline and other neurodegenerative disease conditions as one ages.
Studies on animals at the Douglas Hospital Research Center, McGill University, Quebec, Canada suggest that drinking 1-2 cups of green tea daily is beneficial in cutting down Alzheimer's disease risk.
Also consuming 2 cups and more of green tea is beneficial in lowering risk of Parkinson's and cognitive decline.
Two reports - one in the February 2006 issue of the American Journal of Clinical nutrition and the second by researchers at Japan's Tohuko University show that consumption of 1-2 cups of green tea daily reduced the rate of cognitive decline, memory loss, dementia, and Alzheimer's disease.
The catechin EGCG is believed to benefit in multiple ways in keeping the memory sharp, of those advanced in age.
Green Tea and the Flu
Green tea's main catechin EGCG fight the flu virus and both prevents and reduces the length of the flu attack. Reports published in the November 2005 issue of Antiviral Research indicates this.
Green Tea and Memory/Cognition
In a study a drink containing an extract of green tea was found to activate an area of the brain that is associated with memory.
Green tea polyphenols also increase the blood supply to the brain by widening the blood vessels.
Green tea also prevents senile plaques that hinder cognition from depositing in the brain.
Green Tea and Black Pepper?
It has been observed that simultaneous consumption of black pepper with green tea increases the absorption of epigallocatechin-3-gallate (EGCG) markedly by more than double than if green tea was taken alone.
It would therefore be beneficial to add black pepper to soups, salads or meals if green tea is being taken along with them.
Green tea hydrates even though it contains caffeine since it contains only 30 to 60 mg caffeine in 250 ml of tea compared to more than 100 mg caffeine in coffee. However it may cause insomnia due to the caffeine content.
Note about Bottled Tea
To obtain the antioxidant benefits of green tea do not drink bottled green tea but drink it freshly brewed. These are the findings of a recent report.
Bottled green tea not only had varying amounts EGCG which varied in brands but also has added sugar thus not offering one the full health benefits of green tea.
Always Consult Your Physician
The information provided in this hub is not a substitute for professional medical advice. Please consult your physician, or health care provider before taking any home remedies, supplements or starting a new health regime.
© 2012 Rajan Singh Jolly