Is green tea extract all it has been cracked up to be?
Long touted for the ability to help ‘burn fat,’ ‘boost’ metabolism, and help protect against cancer – green tea extract has faced a lot of criticism for potential “dangers” associated with the health supplement, while many others simply declare it a fad.
What is “EGCG,” and What Are Catechins?
First, it is important to mention the ‘catechins’ in green tea extract – which are the compounds associated with all of the reported health concerns.
Catechins are part of the family of flavonoids. These phenols, antioxidants, are phytochemicals that naturally exist in foods such as tea, berries, and legumes. They are healthful and thought to be responsible for the health-promoting properties in teas.
Catechins seem to possess protective qualities in terms of degenerative diseases and cancers. Some of these compounds, particularly one that is exclusively found in tea – EGCG – have become an area of research and debate as to their safety and efficacy.
Green tea, in particular, seems to contain the highest levels of catechins. The primary catechins in green tea are EGCG (epigallocatechin gallate), EC (epicatechin), GC (gallocatechin), and ECG (Epicatechin gallate). EGCG, for example, is only found in tea.
Should I Be Worried About Liver Function?
Concerns have arisen concerning liver toxicity with high-dose, long-term use of EGCG in particular due to the way catechins are processed in the body when consumed in high amounts.
Research does show that a dose of over 866 mg EGCG per day, when used long-term, could potentially be harmful to the liver.
However, studies using under 800 mg did not correlate to any liver toxicity or damage, while the average intake from tea drinkers is estimated to be 90 to 300mg (not from supplements, but just ol’ fashioned tea infusions).
After a review of 38 different studies, it was concluded that doses of or above 800 mg EGCG for longer than 4 months were associated with markers of liver toxicity in a small percentage (10%) of the population.
Studies showed that there was no reported liver toxicity at levels below 800 mg EGCG per day when taken for up to 12 months.
If more reassurance is needed, hepatotoxicity from Green Tea Extract is quite rare, and in the cases in which it was reported, once the large doses of EGCG were stopped, liver function resolved fully after discontinuation.
There is no documentation of fatal injury from EGCG or Green Tea Extract, even at doses of up to 1,800 mg per day.
For most people, using the supplement at the recommended dosage (typically 200 mg – 600 mg) for a period of 1-3 months is not causing concern, provided they have been cleared by their doctor or physician to do so.
Of course, if you have a pre-existing liver injury, EGCG and Green Tea Extract may not be the right supplement for you.
Most supplements are sold at a dosage of 400 mg Green Tea Extract, which often contains ~200 mg EGCG (50%) – well below the threshold for safety limits.
Real Benefits to EGCG and Catechins from Green Tea Extract
Tea has always been renowned for its weight loss benefits, and for promoting longevity. Most of these benefits can be ascribed to the polyphenol antioxidant content of teas – particularly from catechins.
Studies in animal trials and exploring weight loss in people show promising results, with numerous published studies reaffirming the traditional beliefs in the effects of green tea on body composition, cancer prevention, and longevity.
The first study shows that even in rats fed a high-fat diet for a period of 6 months, those that were also given EGCG were able to reduce body fat while increasing lean mass, glucose tolerance, and better fat synthesis. There were also no negative effects on liver tissue reported. In the second study, 690 mg catechins were consumed for 12 weeks, and body weight, waist size, body fat, and total fat all were dramatically lower in the EGCG group compared to the control, without any other change.
These studies, among many others, display Green Tea Extract and EGCG – catechins – ability to help in reducing body fat and improve metabolic health markers all-around.