Green tea is a drink made from the leaves of Camellia sinensis, which differs from black tea solely in terms of processing. The lesser processing (which minimises oxidation) involved in green tea is the reason why many nutritive substances are preserved compared to black tea.


It is interesting to know that around 5000 years ago, a Chinese physician named Shennong claimed in 'The Divine Farmer's Herb-Root Classic ' that green tea infusions were useful for treating conditions including tumours, abscesses, bladder ailments, and lethargy. Some of these treatments have been shown in modern scientific studies to be true!

A lot of scientific researches (some of which will be covered below) that have been done on green tea showed its potential in preventing diseases. More indepth scientific researches can help to usher in application of green tea to benefit patients having certain types of cancers, Parkinson disease, multiple sclerosis, HIV, stroke and cardiovascular diseases (atherosclerosis).

Tea catechins are strong antibacterial and antiviral agents which can be exploited for treating multiple diseases. The amount of green tea to be drunk per day is rather unclear and varies differently in various scientific researches. Some experts (e.g. Dr. Zuo Feng Zhang, cancer epidemiology researcher at UCLA and studies by the University of Maryland Medical Center) say that the minimum should be two to three cups per day while others claim that it has to be five cups per day (studies by Dr Toru Naganuma of Tohoku University suggests 5 cups per day for prevention of blood cancers)!

Catechins are unstable in non-acidic environments such as the intestines and less than 20 percent of the total remains after digestion. Research by Purdue University (published in the November 2007 Molecular Nutrition and Food Research) suggested that vitamin C addition increased recovered levels of the two most abundant catechins by sixfold and 13-fold, respectively. Also, the best catechin preservation happens at levels of 20 to 50 percent juice. Therefore, maximise your green tea-drinking benefit by also drinking fruit juices that contain high levels of Vitamin C!



Cancer
As we already know, green tea contains a type of polyphenols called catechins which are rich antioxidants. Catechins scavenge for free radicals that can damage DNA and contribute to cancer, blood clots, and atherosclerosis. Epigallocatechin-3-gallate (EGCG), are a type of catechins and are more concentrated in green tea compared to black tea. EGCG was found to be 100 times more effective than vitamin C, 25 times more effective than Vitamin E and twice as powerful as resveratrol in neutralising free radicals. Most of the health benefits from green tea originate from EGCG. Scientific research by Professor Emeritus Tak-Hang Chan, PhD, McGill University showed that a synthetic form of green tea's EGCG can regulate and inhibit cancer growth (prostate cancer tumors) and kill cells that are growing inappropriately.

There are many other studies that show promising results for other types of cancer (breast, stomach, colon, gastric, lung, solid tumor and skin cancers) too. For example, the Journal of the National Cancer Institute (1994) mentioned that drinking green tea reduced the risk of esophageal cancer in Chinese men and women by almost 60%!

Saitama Cancer Research Institute also discovered fewer recurrences of breast cancer and lesser spreading of the cancer cells in women whom drink five cups or more of green tea daily.



Cardiovascular Diseases
Green tea reduces risk of thrombosis (abnormal formation of blood clots), arterial sclerosis, and cerebral strokes which result in heart attacks.

In a 1997 study, University of Kansas researchers concluded that EGCG is twice as powerful as resveratrol (a substance found in red wine and grapes which have been promoted by science as being beneficial for preventing cardiovascular diseases). This may be the reason why the rate of heart disease is quite low among Japanese men even though about 75% of them are smokers.

Green tea also lowers total cholesterol levels and improves the ratio of good (HDL) cholesterol to bad (LDL) cholesterol.



Blood Pressure
Regular consumption of green tea may help to reduce high blood pressure.



Diabetes
There are some whom claim that green tea can aid in regulation of glucose levels (improves glucose metabolisms, prevents sharp increases in blood sugar level and balances the metabolism rate). Thus, it has been claimed that both high blood sugar spikes and resulting fat storage are prevented and can be used in management of diabetes. The researchers from Pharmanex Beijing Pharmacology Center whom conducted test on rat concluded that results clearly show green tea intervention can significantly reduce visceral fat deposition and increase insulin sensitivity.



Rheumatoid Arthritis
A study by Cleveland's Western Reserve University concluded that drinking four or more cups of green tea per day could help prevent rheumatoid arthritis or reduce symptoms in individuals already suffering from the disease.



Alzheimers and Parkinsons
Green tea can delay the deterioration caused by both Alzheimer’s and Parkinson’s. Studies have shown that brain cells were protected from dying and damaged brain cells were restored. (“Green tea polyphenol (–)-epigallocatechin-3-gallate prevents N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced dopaminergic neurodegeneration” by Yona Levites, Orly Weinreb, Gila Maor, Moussa B. H. Youdim, Silvia Mandel)

People consuming green tea are less likely to progress with Parkinson’s. Though modern medical science claims no cure for Alzheimer’s, green tea has been proven to slow the process of reduced acetylcholine in the brain (which leads to Alzheimer’s).

Green tea’s antioxidants helps prevent against cell damage in the brain, which could lead to Parkinson’s. EGCG reduced production of beta-amyloid, a protein that forms the plaques that clog the brains of Alzheimer's patients.

Those who drink more than two cups of green tea per day may reduce the risk of dementia by half and have a 50% lower possibility of having cognitive impairment compared to those who drink less than three cups a week.

Green tea consumption inhibited three important brain-harming chemicals (acetylcholinesterase, butyrylcholinesterase, and beta-secretase). These chemicals are associated with breaking down chemical messengers and formation of plaques and protein deposits in the gray matter of the brain.



Multiple Sclerosis (MS)
The Journal of Immunology (November 1, 2004 Vol. 173 no. 9 5794-5800) stated that EGCG is able to directly protect one against neuronal injury in living brain tissue. It is hoped that EGCG will pave the way for new therapeutic medication to treat MS via combination of its anti-inflammatory and neuroprotective properties.



Human immunodeficiency virus (HIV)
Some scientists in the University of Tokyo discovered that EGCG in green tea can prevent HIV from binding to healthy immune cells. This translates as green tea being able to halt HIV from spreading.



Hepatitis C virus inhibition
Green tea inhibits the hepatitis C virus from entering liver cells according to a study in the journal Hepatology. This is a great news for helping the many patients who don’t respond to standard treatment, as well as people subjected to liver transplants because of the disease, who have a high risk of being reinfected



Herpes treatment
Researchers from the Department of Obstetrics and Gynecology in University of California showed that external genital warts can be treated with catechins from green tea. Green tea increases the effectiveness of topical interferon treatment of herpes and it has been recommended that green tea compress is applied first, then leaving the skin to dry before commencing interferon treatment.



Anxiety, Stress, Depression & Insomnia
Theanine is an amino acid naturally found in tea leaves that relieves anxiety, stress and reduction in depression via its relaxing and tranquilising effect. Theanine also improves mental alertness. Theanine has been included in supplements (eg. In Malaysia - Rilax Zzz® ) to aid patient to sleep better by inducing a relaxing effect and has been found useful for insomniacs.



Improve immune system
Researchers from Kyushu University School of Agriculture have indicated that green tea may help stop the human body from reacting to allergens (e.g. pollen, pet dander and dust). People whom have allergies may want to experiment with green tea drinking to reduce allergy induced symptoms. It has been suggested that green tea is also bactericidal (able to kill bacteria) and prevent food poisoning by killing both the bacteria and the toxins produced by those bacteria.



Weight loss
Green tea promotes weight loss via increase in metabolism which speeds up burning of fats. Did you know that green tea can help burn up to 70 calories in one day? That calculates to 7 pounds in one year! Thus, some claim that, green tea is effective in burning fats at the abs section and it has been included in slimming and weight loss products.



Dental benefits
Studies (e.g. Faculty of Pharmacy, University of the Punjab) suggests that catechins can kill/halt the growth of bacteria (e.g. growth of streptococcus which can cause cavities and gingivitis is reduced ) and viruses that cause throat infections, dental caries and other dental conditions.



Acne, skin care & protection
Green tea can help with skin conditions such as acne, wrinkles, and some even say that it can prevent skin cancer. Signs of ageing are significantly reduced thanks to green tea's antioxidants that fight against skin damaging free radicals and its anti-inflammatory properties. It has been demonstrated that topical application of green tea in humans can reduce damage caused by sunlight. Its ability in protecting skin has been well leveraged in the cosmetics industry. This is evident with the fact that various skincare brands have come up with lines of products using green tea as its main ingredient.



Green tea’s dark nature! (only if you are extremely devoted to green tea!)
Disadvantages of green tea include insomnia due to its caffeine content. Nonetheless, the caffeine content in green tea is still lower than that found in black tea. Drinking more than five cups a day may lead to caffeine-related side effects (such as headache, nervousness, sleep problems, and irregular heartbeat). It has been said that high intake of caffeine may also aggravate some health conditions, which can lead to irritability, insomnia, heart palpitations, and dizziness. Also take note that caffeine overdose can cause nausea, vomiting, diarrhoea, headaches, and loss of appetite. Vomiting or abdominal spasms are symptoms of caffeine poisoning.

Green tea is very sensitive to environmental pollutants such as aluminium and is known to absorb them. It is best to drink green tea, which leaves are grown organically to avoid consumption of dangerous environmental pollutants. Green tea can also decrease the amount of iron from food being absorbed into the body. It is best to avoid drinking tea around mealtimes especially for those suffering from anaemia.

People suffering from heart problems or high blood pressure, kidney problems, liver problems, stomach ulcers, and psychological disorders, or any type of anxiety issues should consult with healthcare professionals should they want to take green-tea based supplements. Similarly, people with anaemia, diabetes, glaucoma, or osteoporosis should consult their health care provider before drinking green tea or taking an extract. Pregnant and breastfeeding women are advised to avoid drinking green tea due to its caffeine content.

Excessive drinking of green tea have been linked to liver and kidney damage but according to Chung Yang of Rutgers, the State University of New Jersey, one does not need to worry as up to 10 small cups of green tea a day poses no harm.

Generally, from the findings as illustrated in the above, the benefits from drinking green tea shows great promise. However, it is always important to remind oneself that anything in excess is never good. Otherwise, we would say that the moderate daily intake of green tea would do good for one's health.



You may also be interested in:
Turmeric: One of Nature’s Most Powerful Healer
Chia Seeds, Tiny Seeds With Huge Health Potential
Stevia, A Natural Sweetener



Authors: Silambarasu Karuppiah & Genevieve Tan Shu Thung

Copyright © 2012 Sandhya Maarga Holistic Living Resources
Holistic Living Annex (AUGUST 2012)