Q & A Library
Green Tea for Longer Life?
I heard that something in green tea could help people live longer. Is this true?
Answer (Published 10/22/2009)
It might be. You may be referring to findings from a study in Hong Kong suggesting that people who drink green tea regularly may be younger, biologically, than those who don't drink green tea or consume only small amounts. The science here is somewhat complex, so bear with me while I summarize this fascinating new study. The researchers looked at the length of telomeres, repeating DNA sequences at the ends of chromosomes. (One expert suggests thinking about telomeres as the caps on the ends of shoelaces that prevent the laces from unraveling.) In cells, telomeres prevent chromosomes from fusing with one another or rearranging - undesirable changes that could lead to cancer and other life-threatening diseases.
Research has shown that as cells replicate and age, telomeres get shorter and shorter and that when telomeres finally disappear, the cells can no longer replicate. Some experts have suggested that the length of telomeres may be a marker for biological aging. The shorter your telomeres, the "older" you are. Earlier studies have suggested that telomeres are highly susceptible to oxidative stress.
Now, for the Hong Kong study findings: researchers looked at telomere lengths of 976 Chinese men and 1,030 Chinese women, all over the age of 65. All the study participants completed a food frequency questionnaire.
The researchers reported that telomere length was associated only with tea drinking – participants with the highest intake, three cups per day of tea, had longer telomeres than participants who drank an average of only one quarter of a cup of tea daily. Most participants drank green tea while a few drank black tea. The investigators reported that the average difference in telomere length corresponded to "approximately a difference of five years of life" and that the "antioxidative properties of tea and its constituent nutrients may protect telomeres from oxidative damage in the normal aging process." The study was published online on August 12, 2009.
Incidentally, a recent U.S. study found that telomere length was longer in women who took multivitamins regularly. Here, researchers looked at multivitamin use in a group of 586 women between the ages of 35 and 74. They found that higher intakes of the antioxidant vitamins C and E from food were associated with longer telomere length. The findings were published in the June 2009 issue of the American Journal of Clinical Nutrition.
Andrew Weil, M.D.
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