Dementia Risk Reduction: Need Another Reason to Drink Green Tea?

green tea cup and pot

There’s quite a lot to be said for green tea. It has no calorific content of its own to speak of, and doesn’t need sugar or cream to taste great. A steaming cup can warm you up in winter, or you can drop a couple of ice cubes in and cool off with a glass in midsummer. Now, new research suggests that aside from keeping your body trim and your palate pleased, a daily cup of green tea may help keep your mind sharp by warding off the onset of dementia.

Evidence: Researchers from Kanazawa University (Japan), led by neurology professor Masahito Yamada, recently wrapped up a five-year study on the connection between green tea consumption and mental health. During 2007 and 2008, the team interviewed 982 residents over the age of 60 living in Nanao City, located on the Noto Peninsula of Ishikawa Prefecture.

The study participants were asked about their consumption of green tea, black tea, and coffee, and also completed a series of exercises designed to gauge their cognitive capabilities. Five years later, the researchers once met with the 490 subjects who could be located and were available for retesting.

Japanese holding green tea

By comparing the results of the two tests, researchers were able to gauge which participants had developed dementia or other, less severe mental disorders in the time between the two meetings. Arranging the data by how much green tea the group drank showed an astounding difference.

  • Out of the 157 subjects who said they drank green tea every day, only 18, or 11.5 percent, showed mental disorders. The numbers were similar for the subset that drank green tea one to six times a week, with 29 out of 195, or 14.9 percent, having developed problems.
  • In contrast, 43 of the 138 people who said they never drank green tea – a whopping 31.2 percent – displayed signs of diminished mental functions. In other words, drinking green tea daily was associated with a reduction in a subject’s risk of developing dementia or dementia-like symptoms to roughly one-third of those who never partook of Japan’s favorite non-alcoholic beverage.

On the other hand, the researchers were unable to find any such benefits for drinkers of coffee or black tea.

My Take: This isn’t the first study to show a possible link between green tea and mental health. Professor Yamada asserts that the results of his team’s study have an especially high level of credibility, due to the length of time between the two tests. I would soften the statement, as while the study shows an association between green tea consumption and a lower risk of dementia, it does not establish causality. Still, this study adds to a growing body of evidence pointing to a potential role of green consumption in reducing your risk of dementia. Now if you’ll excuse me, I think my tea is ready.

The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

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Harvard AB Yale MD UPenn Radiation Oncology Radiation Oncologist, Seattle area

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