Green tea benefits for health

Benefits of green tea: science and myths

Green Tea Benefits
Fig. 1 – Green Tea Benefits

Tea drinking, particularly green tea, has always been associated, at least in East Asia cultures (mainly in China and Japan) with health benefits. Only recently, the scientific community has begun to study the health benefits of tea consumption, recognizing its preventive value in many diseases.

Green tea benefits in preventing cancer

Several epidemiological and laboratory studies have shown encouraging results with respect to possible preventive role of tea, particularly green tea and its catechins, a subgroup of flavonoids (the most abundant polyphenols in human diet) against the development of some cancers like:

  • oral and digestive tract cancers;
  • lung cancer among those who have never smoked, not among smokers.

Tea polyphenols, the most active of which is epigallocatechin-3-gallate (EGCG), seem to act not only as antioxidants, but also as molecules that, directly, may influence gene expression and diverse metabolic pathways.

Green tea and cardiovascular disease

Cardiovascular disease is the main cause of deaths worldwide, particularly in low- and middle-income countries, with an estimate of about 17 million deaths in 2008 that will increase up to 23.3 million by 2030.
Daily tea consumption, especially green tea, seems to be associated with a reduced risk of developing cardiovascular disease, such as hypertension and stroke.
Among the proposed mechanisms, the improved bioactivity of the endothelium-derived vasodilator nitric oxide (NO), due to the action of tea polyphenols that enhance nitric oxide synthesis, and/or decrease superoxide-mediated nitric oxide breakdown seem to be important.

Green tea and antioxidant properties

Tea polyphenols may act, in vitro, as free radical scavengers.
Since radical damage plays a pivotal role in the development of many diseases such as atherosclerosis, rheumatoid arthritis, cancer, or in ischemia-reoxygenation injury, tea polyphenols, particularly green tea catechins, may have a preventive role.

Green tea benefits in weight loss and weight maintenance

Green tea, but also oolong tea, that is, catechins and caffeine rich teas, has a potential thermogenic effect. This has made them a potential tool for:

  • weight loss, by increasing energy expenditure and fat oxidation;
  • weight maintenance, ensuring a high energy expenditure during the maintenance of weight loss.

Indeed, it has been shown that green tea and green tea extracts are not an aid in weight loss and weight maintenance, since:

  • they are not able to induce a significant weight loss in overweight and obese adults;
  • they are not helpful in the maintenance of weight loss.

Green tea and preventing dental decay

Animal and in vitro studies have shown that tea, and in particular its polyphenols, seems to possess:

  • antibacterial properties against pathogenic action of cariogenic bacteria, as Streptococcus mutans, particularly green tea EGCG;
  • inhibitory action on salivary and bacterial amylase (it seems that black tea thearubigins and theaflavins are more effective than green tea catechins);
  • it is able to inhibit acid production in the oral cavity.

All these properties make green tea and black tea, beverages with potential anticariogenic activity.

References

Arab L., Khan F., and Lam H. Tea consumption and cardiovascular disease risk. Am J Clin Nutr 2013;98:1651S-1659S doi:10.3945/ajcn.113.059345

Dwyer J.T. and Peterson J. Tea and flavonoids: where we are, where to go next. Am J Clin Nutr 2013;98:1611S-1618S doi:10.3945/ajcn.113.059584

Goenka P., Sarawgi A., Karun V., Nigam A.G., Dutta S., Marwah N. Camellia sinensis (Tea): implications and role in preventing dental decay. Phcog Rev 2013;7:152-6 doi:10.4103/0973-7847.120515

Grassi D., Desideri G., Di Giosia P., De Feo M., Fellini E., Cheli P., Ferri L., and Ferri C. Tea, flavonoids, and cardiovascular health: endothelial protection. Am J Clin Nutr 2013;98:1660S-1666S doi:10.3945/ajcn.113.058313

Hursel R. and Westerterp-Plantenga M.S. Catechin- and caffeine-rich teas for control of body weight in humans. Am J Clin Nutr 2013;98:1682S-1693S doi:10.3945/ajcn.113.058396

Hursel R., Viechtbauer W. and Westerterp-Plantenga M.S. The effects of green tea on weight loss and weight maintenance: a meta-analysis. Int J Obesity 2009;33:956-961 doi:10.1038/ijo.2009.135

Jurgens T.M., Whelan A.M., Killian L., Doucette S., Kirk S., Foy E. Green tea for weight loss and weight maintenance in overweight or obese adults. Editorial group: Cochrane Metabolic and Endocrine Disorders Group. 2012:12 Art. No.: CD008650 doi:10.1002/14651858.CD008650.pub2

Lagari V.S., Levis S. Phytoestrogens for menopausal bone loss and climacteric symptoms. J Steroid Biochem Mol Biol 2014;139:294-301 doi:10.1016/j.jsbmb.2012.12.002

Lambert J.D. Does tea prevent cancer? Evidence from laboratory and human intervention studies. Am J Clin Nutr 2013;98:1667S-1675S doi:10.3945/ajcn.113.059352

Lethaby A., Marjoribanks J., Kronenberg F., Roberts H., Eden J., Brown J. Phytoestrogens for menopausal vasomotor symptoms. Cochrane Database Syst Rev 2013:10;12 Art. No.: CD001395 doi:10.1002/14651858.CD001395.pub4

Levis S., Strickman-Stein N., Ganjei-Azar P., Xu P., Doerge D.R., Krischer J. Soy isoflavones in the prevention of menopausal bone loss and menopausal symptoms: a randomized, double-blind trial. Arch Intern Med 2011:8;171(15):1363-9 doi:10.1001/archinternmed.2011.330

Lorenz M. Cellular targets for the beneficial actions of tea polyphenols. Am J Clin Nutr 2013;98:1642S-1650S doi:10.3945/ajcn.113.058230

Sharma V.K., Bhattacharya A., Kumar A. and Sharma H.K. Health benefits of tea consumption. Trop J Pharm Res 2007;6(3):785-792.

Yang Y-C., Lu F-H., Wu J-S., Wu C-H., Chang C-J. The protective effect of habitual tea consumption on hypertension. Arch Intern Med 2004;164:1534-1540 doi:10.1001/archinte.164.14.1534

Yuan J-M. Cancer prevention by green tea: evidence from epidemiologic studies. Am J Clin Nutr 2013;98:1676S-1681S doi:10.3945/ajcn.113.058271

One thought on “Green tea benefits for health”

  1. Really Green tea not only normal tea. It’s so many medicne quality & health benefitis.
    I don’t know before it’s a existing cancer protect element & protect capable from cardiovascular disease and I know many unknown information.
    Thank you very much

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