Green tea extracts and liver disease

green tea extractI think we are safe in saying that green tea doesn’t make taste buds frolic. So why do people drink it? The same reason for which the Chinese have been consuming it for millennia. Its supposed health benefits. Green tea doesn’t contain the flavourful compounds that form when tea leaves are allowed to ferment. During fermentation enzymes are released that convert the naturally occurring polyphenols in the leaves to a host of tasty compounds. Instead of being fermented, green tea is made by steaming or drying fresh tea leaves in order to prevent oxidation of the polyphenols. It is these polyphenols that in laboratory and animal studies show anti-cancer effects as well as increased rates of metabolism.

But how can on benefit from tea’s polyphenols without having to put up with green tea’s unappealing flavor? Supplement manufacturers have found a way. Just extract the catechins, the main class of polyphenols in tea, and plunk them in a pill. Then promote the pill as a cancer-fighting or fat burning supplement. But here we run into a problem. Such dietary supplements are poorly regulated and the amount of catechins they contain can be far greater than that available from drinking tea. The high doses may indeed help to increase metabolism and result in weight loss but possibly at a high cost. Just ask the teenager who walked into the emergency room at Texas Children’s Hospital with his chest, face and eyes bright yellow due to severe liver damage after using a concentrated green tea extract he bought at a nutrition store as a “fat burning” supplement. Doctors feared he may need a liver transplant but luckily his liver, an organ that has regenerative properties, managed to recover. He did, however, have to give up sporting activities and will require regular checkups of his liver function.

Unfortunately this is not an isolated case and such cases are not limited to green tea extracts. Various herbal supplements have been linked with liver damage, some because of undeclared ingredients, such as steroids. These are promoted as bodybuilding supplements and may actually have an effect because of the hidden steroids. People generally assume that herbal products that are sold are tested for safety and efficacy but this is not the case. Until regulations are tightened the incidence of liver damage from dietary supplements is going to continue to increase.

 Joe Schwarcz

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