Drinking green tea weeks before taking green tea extract supplements for weight loss may offer protection against potential liver toxicity, according to researchers in Penn State's College of Agricultural Sciences.
Tea, Camellia sinensis, is rich in catechins, polyphenols that are natural antioxidants, and a number of animal studies have shown the preventive effects of green tea polyphenols against obesity.
During the study, researchers gave mice high doses of the green tea polyphenol epigallocatechin-3-gallate (EGCG), which was equivalent to the amount of the polyphenol found in some dietary supplements taken by humans. The research data shows that dietary pre-treatment with the green tea polyphenol protects mice from liver toxicity caused by subsequent high oral doses of the same compound. Researcher Josh Lambert suggested that the research has relevance to people who are taking or are considering taking supplements containing green tea extract.
Lambert said, "Drinking green tea rather than taking supplements will allow you to realize the benefits and avoid the risk of liver toxicity and the beneficial effects that people have reported as being associated with green tea are the result of dietary consumption rather than the use of supplements. The relative risk of using supplements remains unclear. A recent analysis of 11 human trials with green tea preparations reported a nearly three-pound average body weight loss in intervention groups compared to control groups. Green tea's effect on weight loss may be more noticeable if a person exercises."
Lead researcher Sarah said, "It appears that EGCG can modulate its own bio-availability and that dietary treatment may reduce the toxic potential of acute high oral doses of EGCG. These data may partly explain the observed variation in liver toxicity response to dietary supplements containing green tea."
The study appears in journal Food and Chemical Toxicology.