Everything in moderation: does that go for green tea, too?

William Atkins
Monday, 07 May 2007 02:41

Science - Health

The polyphenols (antioxidants) in green tea are thought to help in preventing chronic diseases such as cardiovascular (heart) disease, cancer, and various inflammatory diseases. (Other foods also possess the same benefit, including olive oil, berries, cereals.)

However, according to the Rutgers researchers, when large quantities of polyphenols were given to laboratory rodents and dogs, they died from liver poisoning. Cases are also sited where humans overdosed on green-tea-bases supplements, resulting in liver toxicity. Less severe cases found that people have symptoms associated with liver problems when taking green-tea supplements but those symptoms disappeared when the pills were discontinued.

The Rutgers researchers suggest that about ten small cups of green tea each day is safe. However, they stress that one green-tea supplement pill can contain up to 50 times as much polyphenol as one cup of tea.

The conclusions of Chung Yang, Joshua Lambert, and Shengmin Sang (titled “Possible controversy over dietary polyphenols: Benefits vs. risks”) appear in the American Chemical Society’s journal Chemical Research in Toxicology, 2007, volume 20, pages 583-585.

However, the paper is not without its critics. Daniel Fabricant, who is vice president of scientific and regulatory affairs at The Natural Products Association, states that adverse effects of polyphenol are virtually nonexistent in many different studies performed on green tea. Fabricant calls the paper of Yang-Lambert-Sang “paper science with no real world value”. [Fabricant]

Whatever the truth is here, it is well known that moderation is good in just about everything we do.

Please note the ITwire article “Pistachios, Coffee, and Green Tea: Good, Good, and Good for you!” at http://www.itwire.com.au/content/view/11751/1066/.