most important studies on green tea


The individual studies:

Half of all deaths in the industrialised nations are due to cardiovascular diseases, and the trend is increasing.[1] The effects proven in studies on the cardiovascular system, which are not just therapeutic, but also preventative, can be hoped for.

The effect on mortality due to cardiovascular failure has been very impressively demonstrated in several studies.[2] A meta-analysis of 17 studies showed that consuming three cups of tea a day allows for a reduction in cardiovascular risk of about 11 %.[3]

In a study on 1,900 patients who had an acute myocardial infarction, those who drank up to 14 cups of tea a week the year before the infarction had a 20 % lower mortality rate; with more than 14 cups a week, the death rate even fell by half.[4]

Yang and Koo showed that green tea-containing catechins prevent harmful LDL oxidation in endothelial cells.[5] In another study, Japanese researchers demonstrated that EGCG contained in green tea completely suppresses collagen-induced platelet aggregation (blood clumping).[6]

The Ohsaki study

An eleven-year study in Japan involving 40,530 people between the ages of 40 and 79 has shown amazing positive features in the cardiovascular system. The subjects drank at least five cups of green tea daily. Male subjects were able to reduce their death rate by 12 %, female subjects by 23 %. Cardiovascular disease mortality fell significantly, 31 % for women and 22 % for men. [7]

The protective effect on the cardiovascular system is attributed to the polyphenols contained in green tea (epigallocatechin gallate, EGCG).

Green tea for high blood pressure/high blood pressure

High blood pressure is considered a dangerous factor, which often gradually leads to heart failure. In 1,500 volunteers at Cheng Kung University in Taiwan, the risk of high blood pressure was reduced by 46 % with daily tea consumption of two to four cups, with a higher daily consumption reducing the risk by as much as 65 %.[8]

Green tea inhibits atherosclerosis

The progression of atherosclerosis, which is mainly responsible for heart attack and stroke, has been arrested in various studies.[9]

Effect of green tea on cancer

While half of all deaths in developed countries are due to cardiovascular disease, the second most common cause is cancer. And so, one in two people[10] suffers from cancer.

Japanese researchers may have been the first to observe the biochemical mechanism that explains the anti-cancer effect: according to their research, an ingredient of green tea attaches specifically to tumour cells and slows the growth of cancer.

This docking site is important for the formation of cell contacts and is present on different tumour cells. According to the statement, enjoying just two to four cups of green tea a day triggers this protective effect.[11]

Tea flavonoids, which are particularly common in green tea, are potent antioxidants that protect cell proteins and DNA from cancer.[12] Tea flavonoids affect the intracellular signalling cascades and intercellular communication, enabling them to prevent tumorigenesis and inhibit the growth of acute cancer.[13] Cancer growth and metastasis are inhibited by the abundance of EGCG present in green tea.[14] There is a large body of work on the diverse effects of tea extracts on different tumour cell lines.[15]

Prostate cancer

A study on patients with prostate cancer conducted at the Center for Human Nutrition at the David Geffen School of Medicine at UCLA revealed that the EGCG derived from green tea was detectable in tumours and could significantly inhibit tumour cell growth. The researchers concluded that green tea could help prevent prostate cancer and inhibit its growth.

Effect of green tea on diabetes

In in vitro tests, the activation of insulin production was demonstrated to be more than 15-times higher for the EGCG contained in green tea.[16] Another Japanese study showed a prophylactic effect against diabetic nephropathy, a diabetes-related kidney disease. The researchers based their findings on the assumption that the polyphenols contained in green tea intercept free radicals, possibly reducing the accumulation of glucose in the body's own proteins, providing effective protection for the kidneys.[17]

Effect of green tea on Huntington's chorea

Huntington’s chorea is an inherited neuro-degenerative disease. It has been demonstrated on model organisms that green tea can delay the plaque formation that leads to the disease. The researchers attributed the effect to the substance EGCG, which is present in green tea.[18]

Green tea inhibits arthritis 

In animal experiments, the polyphenol present in green tea reduced the symptoms of arthritis and had an anti-inflammatory effect.[19]

Effect of green tea on kidney function

In animal experiments, tannin found in green tea showed positive effects on kidney function.[20]

Effect of green tea on Alzheimer's and Parkinson's

Alzheimer's and Parkinson's are among the neurodegenerative diseases caused by the formation of amyloid fibrils. It has been found that EGCG contained in green tea prevents the formation of amyloid fibrils by binding to native, unfolded polypeptide chains. As a result, harmless oligomers are formed instead of the toxic amyloid fibrils.[21]


Antimicrobial effect of green tea

Several studies have shown the antimicrobial effects of green tea catechins.[22]

Effect of green tea on gum disease

Green tea catechin reduces gum diseases, such as periodontal disease.[23]

Green tea prevents tooth decay

Green tea's EGCG and ECG inhibit the growth of caries bacteria, the streptococci.[24]

Green tea for multiple sclerosis

Chronic inflammatory processes in the central nervous system are responsible for multiple sclerosis. As recent research at the Institute of Neuroimmunology of the Charité in Berlin under the direction of Professor Frauke Zipp suggests, green tea may prevent this, or at least curb it. This positive effect is again attributed to the green tea flavonoid EGCG (epigallocatechin-3-gallate). This can obviously both throttle a misguided immune system and protect the nerve cells from harmful influences. The scientists tested the effectiveness of the substance in animal experiments as well as in cultures of human immune and nerve cells and stated: 

EGCG is the first drug we have found that is administered orally and has immunomodulatory and nerve cell protecting properties’.

This important finding could be a milestone in the treatment of multiple sclerosis. The effect is justified by the scientists as follows:

EGCG seems to attack the destructive disease processes of multiple sclerosis from two angles. In addition, the substance has the advantage that it is unlikely to cause side effects’.

Furthermore, the scientists Aktas, Prozorovski and their colleagues were able to prove that the EGCG contained in the green tea intervenes in the growth of activated immune cells, known as T-lymphocytes, and inhibits the expansion of these harmful cells. Alongside this, the EGCG protects the nerve cells from various harmful substances that are released by the immune system.

Aktas: ‘The results are very promising, especially since the therapeutic successes with previously known treatment options are comparatively modest. Our experiments have shown that EGCG also works on animals which are already ill. This corresponds to the treatment situation in patients presenting to their doctor after the first episode of multiple sclerosis’.

In the next step, further studies are planned to be performed on patients with relapsing-remitting MS. ‘If these studies are positive, EGCG may soon provide a new treatment for patients with multiple sclerosis’, said Aktas.[25]

Green tea enhances the effects of antibiotics

Dr. Mervat Kassem, an Egyptian scientist, has been able to demonstrate that antibiotics work better on a large scale when patients also take green tea. Together with his research team, he tested the effect on pathogens of 28 infectious diseases, with the result that green tea increased the effect in all cases and even pathogens that were no longer responsive to the antibiotics became vulnerable again.[26]

Green tea helps combat osteoporosis

Green tea contains large amounts of manganese, which is responsible inter alia for the formation of connective tissue and bone. Manganese transports calcium from food into the bones and can therefore counteract osteoporosis very successfully.



Green tea for heartburn and irritated stomach

The aluminium compounds contained in green tea are not toxic, they act as a buffer against stomach acid and thus counteract heartburn and gastric irritation.

Green tea promotes fat burning and helps weight loss

Several studies support the positive influence of green tea on body weight. It supports the metabolism by accelerating thermogenesis and thus helps with weight loss.[27] This is attributed to the catechins and caffeine contained in the green tea.

Thermogenesis increases fat burning and lasts up to 24 hours after tea consumption. Green tea proves to be a potent aid to dieting.


[2] Hertog et al., 1997, Nakachi et al., 2000, Arts et al., 2001 or Kuriyama et al., 2006.

[3] Peters et al., 2001

[4] Mukamal et al., 2002.

[5] Yang and Koo, 2000

[6] Sagesaka-Mitane et al., 1990

[7] Shinichi K. et al.: Green tea consumption and mortality due to cardiovascular disease, cancer and all causes in Japan, in JAMA, 296/2006, pp. 1255-65.


[9]Geleinjse et al., 1999; Sazuki et al., 2000


[11]  Nature Structural & Molecular Biology  (online pre-publication DOI: 10.1038/nsmb743

[12] Hecht and Hoffmann, 1998; Gordon, 1996; Yoshioka et al., 1996.

[13]Lin et al., 1999, Chen et al., 1999, Chung et al., 1999.

[14] Jankun et al., 1997.

[15] Dufresne and Farnworth, 2001.

[16] Anderson and Polanski, 2002

[17], Green Tea and Rooibos Tea in Kidney Disease caused by Diabetes, retrieved on November 26, 2007

[18]Press release from the Max Delbrück Centre for Molecular Medicine (MDC) Berlin-Buch, September 8, 2006, Green tea Reduces Plaque Formation in Huntington's Chorea  - First results in model organisms; Ehrnhoefer D. et al., Green tea (-) – epigallocatechin-gallate modulates early events in Huntington misfolding and reduced toxicity in Huntington's disease models, in Journal Human Molecular Genetics, 15/2006, pp. 2743-51.

[19] Haqqi et al., 1999

[20] Yokozawa et al., 1996

[21] Ehrnhoefer et al. Nat. Struct. Mol. Biol. 2008, doi:10.1038/nsmb.1437

[22] Diker et al., 1991; Inoue et al.; 1996, Toda et al., 1991

[23] Kushiyama M., Shimazaki Y., Murakami M., Yamashita Y. (2009). Relationship between intake of green tea and periodontal disease. Journal of Periodontology. 80, pp. 372-377

[24] Sakanaka et al., 1990



[27] Dulloo AG., Duret C., et al. ‘Efficacy of a green tea extract rich in catechins polyphenols and caffeine in increasing 24h energy expenditure and fat oxidation in humans’ Am J. Clinc Nutr. 1999; 70 p. 1040–1045.