Green Tea Supplement Side Effects
Harmful Extract Pills?

Take any healthy food excessively, it is likely to turn into a poison.

Green tea supplements have been found to kill dogs at high doses. It is a double whammy. A green tea supplement is usually made from the lowest grade tea. And now the scientists are warning it is easy to overdose.

One study found that green tea is good for you only when used in moderation. While it has been found to prevent heart disease and cancer, it could cause liver and kidney damage when consumed in very large quantities.

"People shouldn't be too alarmed by this, but those taking supplements may experience problems," says lead author Chung Yang of Rutgers, the State University of New Jersey.

"Up to 10 small cups of green tea a day is fine. Problems are likely in people who take supplements, which can contain up to 50 times as much polyphenols as a single cup of tea."

Another study conducted by Bonkovsky reported 9 individuals suffering from liver toxicity after overdosing on supplements (at 10 to 29 milligrams per kilogram per day). 

Their symptoms disappeared when they stopped taking the pills, only to return when they started taking them again. A cause–effect relationship was suggested but not proven, as most of the products contained other ingredients in addition to green tea extract.

A laboratory study performed by the University of Mississippi found that high doses of green tea extract containing epicatechin gallate (ECG) may increase tumour growth. Low doses have been found to suppress new tumour growth with no observed side effects.

Researchers cautioned that results are preliminary. They also said the benefits of green tea are evidenced in those who drink the tea, but not necessarily those who consume supplements.

This green tea supplement side effects study was published in the Journal of Natural Products.

According to the Mayoclinic, one cup of tea contains 80 to 100 milligrams of green tea polyphenols, depending on the strength and size of the cup. 

A green tea supplement can contain anywhere from 100 to 750 milligrams per tablet. Currently, there is no established recommended dose.

To decide how many green tea tablets to consume, follow the advice given by your green tea product or medical adviser.

Drinking green tea is safer. It is difficult to overdose. The United Kingdom Tea Council recommends up to 6 cups of tea a day.

Joshua D. Lambert, Shengmin Sang, and Chung S. Yang (2007). Possible Controversy over Dietary Polyphenols: Benefits vs Risks. Chem. Res. Toxicol., 20 (4), 583 -585, 2007. 10.1021/tx7000515 S0893-228x(70)00051-6

Bonkovsky, H. L. (2006). Hepatotoxicity associated with supplements containing Chinese green tea (Camellia sinensis). Ann. Intern. Med. 144, 68-71.

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