Is Green Tea the Panacea We Have Been Searching For? A Review of the Scientific Literature on Green Tea and Human Health.

There are many claims surrounding the health benefits of consuming green tea, some of which involve its use in the treatment of medical conditions as wide ranging as cancer, diabetes, and neurodegenerative disorders. The desire for the use of non-toxic and natural drugs to treat various diseases makes any health-benefitting claims about green tea and its components important to investigate for their potential public health benefits. I conducted a critical review of the research literature on green tea and its effects on human health and synthesised the results. There is convincing epidemiological evidence pointing to the health benefits derived from consumption of green tea, but National Institutes of Health (NIH)-funded clinical trials are few in number and have produced only modest results. The main biologically active compound in green tea, epigallocatechin gallate (EGCG), does not demonstrate specific binding to biological molecules and varies greatly in its concentration in green tea. EGCG also has a weak, but notable, relationship between dose and maximum plasma concentration in humans; however, most concentrations of EGCG used in laboratory studies are far beyond the physiologically achievable levels. Additionally, there is evidence that high doses of EGCG may lead to liver damage. Finally, green tea polyphenols are implicated in a vast number of interactions, but these are not well understood and suggest the possibility of pan-assay interference. Without clear mechanistic evidence or reliable dosing strategies, it is unlikely that green tea will be suitable for pharmaceutical uses in the treatment of human disease