Green tea diet and its benefits

Green tea has been claimed to have many health benefits and numerous properties for which it is known and used worldwide, some of these benefits and properties include claims about its anti-cancer properties, its ability to lower cholesterol, protect the skin against oxidation and aging, cardiovascular disease and neurodegenerative disorders, being a powerful antioxidant with even more antioxidant capacity than some vitamins as vitamin C or E, and last but not least, green tea diet claims green tea is able to help you lower your weight, but, how much truth is behind that statement? Let's find out what scientist and doctors said about such claim and which scientific studies and clinical trials can confirm or deny such statement.

CAMELIA SINENSIS

Family: Teaceae
Genus: Camelia
Common name: Green tea

Green tea extract green tea extract high in catechins reduces body fat [7]

GREEN TEA CATECHINS

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Green tea is rich in catechins, a type of flavonoids that can be found in apples, cherries, pears, tea and even in wine and known to exert antioxidant properties. In fact, catechins are the major active constituent found in tea [1]. It is believed that catechins have a direct influence on body fat reduction in humans, or at least that's what a study on the subject showed, after verifying the effects of green tea intake in two study groups, on which the group having a higher intake of tea rich in catechins experienced a lower body weight, BMI, body fat and waist circumference compared with the group having a lower intake of catechins [1].

A excess of polyphenols intake could lead to harmful situations for our body health

GREEN TEA AND MILK DIET

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Another study on the effects of green tea combined with milk (milk-protein), showed also that green tea is even more effective on weight reduction when combined with milk protein.

It seems that this effect is achieved by the diet-induced thermogenesis that the combination of both, green tea and milk protein, exerts on humans, showing how green tea and proteins can induce weight loss when consumed in adequate amounts.

These effects are possibly due to the complexes formed between proteins and tea polyphenols [2].

Green tea is even more effective on weight reduction when combined with milk protein

TOO MUCH POLYPHENOLS MAY BE DANGEROUS

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Are green tea diet pills safe? Is diet green tea good for you? can too much green tea be harmful?

As they say, even the best things in excess could be harmful. Green tea polyphenols are not a exception of the rule, and as it was published in the April 2007 issue of Chemical Research in Toxicology, an excess of polyphenols intake could lead to harmful situations for our body health, becoming even toxic [5,6].

In spite no known research on humans could yet prove it, in laboratory trials done on dogs, excessive doses of epigallocatechin-3-gallate (EGCG) were linked to liver, kidney and gastrointestinal toxicities, but these toxic effects are believed to occur on individuals having an additional green tea supplement intake, most of them containing up to fifty times the polyphenols content of one single cup of tea [5]. Already back in 2008 regulatory agencies in France and Spain suspended market authorization of a weight-loss product containing green tea extract because of hepatotoxicity concerns [8].

Anyway this amount of polyphenols will of course never enter into any normal green tea diet.

GREEN TEA AND MILD COGNITIVE IMPAIRMENT

A recent scientific study on the use of a combination of green tea extract and l-Theanine, demonstrated the beneficial effects that such a cocktail had on the improvement of cognition.

In the study, where a double-blind placebo control was used, patients affected by mild cognitive impairment (MCI), among which 13 were men and 32 women, the volunteers performed different neuropsicological tests and their electroencephalography analyzed.

The results showed that an increase on memory and selective attention on those receiving the green tea extract and l-Theanine cocktail, showing the potential use and benefits of green tea extract and l-Theanine for the treatment of cognitive impairment patients.

REFERENCES

[1] Ingestion of a tea rich in catechins leads to a reduction in body fat and malondialdehyde-modified LDL in men.
Nagao T, Komine Y, Soga S, Meguro S, Hase T, Tanaka Y, Tokimitsu I.
Health Care Products Research Laboratories No.1, Kao Corporation, Tokyo.

[2] Consumption of milk-protein combined with green tea modulates diet-induced thermogenesis.
Hursel R, Westerterp-Plantenga MS.
Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, P.O. Box 616, Maastricht 6200 MD, The Netherlands;

[4] Anti-obesity action of oolong tea.
Han LK, Takaku T, Li J, Kimura Y, Okuda H.
2nd Department of Medical Biochemistry, School of Medicine, Ehime University, Japan.

[5] Diet and Nutrition: Temperance in Green Tea
M. Nathaniel Mead

[6] April 2007 issue of Chemical Research in Toxicology.

[7] A green tea extract high in catechins reduces body fat and cardiovascular risks in humans.
Nagao T, Hase T, Tokimitsu I.
Health Care Food Research Laboratories, Kao Corporation, 2-1-3, Bunka, Sumida-ku, Tokyo, 131-8501, Japan.

[8] Safety of green tea extracts : a systematic review by the US Pharmacopeia.
Sarma DN, Barrett ML, Chavez ML, Gardiner P, Ko R, Mahady GB, Marles RJ, Pellicore LS, Giancaspro GI, Low Dog T.
US Pharmacopeia, Rockville, Maryland 20852-1790, USA.

[9] A Combination of Green Tea Extract and l-Theanine Improves Memory and Attention in Subjects with Mild Cognitive Impairment: A Double-Blind Placebo-Controlled Study.Park SK, Jung IC, Lee WK, Lee YS, Park HK, Go HJ, Kim K, Lim NK, Hong JT, Ly SY, Rho SS. LG Household and Health Care Co., Ltd., Daejeon, Korea.