日本人提供了第一个流行病学证据，喝茶也许可以预防痴呆。

American Journal of Clinical Nutrition, Vol. 83, No. 2, 355-361, February 2006
© 2006 American Society for Clinical Nutrition

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ORIGINAL RESEARCH COMMUNICATION

Green tea consumption and cognitive function

Background: Although considerable experimental and animal evidence shows that green tea may possess potent activities of neuroprotection, neurorescue, and amyloid precursor protein processing that may lead to cognitive enhancement, no human data are available.

Design: We analyzed cross-sectional data from a community-based Comprehensive Geriatric Assessment (CGA) conducted in 2002. The subjects were 1003 Japanese subjects aged 70 y. They completed a self-administered questionnaire that included questions about the frequency of green tea consumption. We evaluated cognitive function by using the Mini-Mental State Examination with cutoffs of <28, <26, and <24 and calculated multivariate-adjusted odds ratios (ORs) of cognitive impairment.

Results: Higher consumption of green tea was associated with a lower prevalence of cognitive impairment. At the <26 cutoff, after adjustment for potential confounders, the ORs for the cognitive impairment associated with different frequencies of green tea consumption were 1.00 (reference) for 3 cups/wk, 0.62 (95% CI: 0.33, 1.19) for 4–6 cups/wk or 1 cup/d, and 0.46 (95% CI: 0.30, 0.72) for 2 cups/d (P for trend = 0.0006).

Conclusion: A higher consumption of green tea is associated with a lower prevalence of cognitive impairment in humans.