Green tea consumption and cognitive function: a cross-sectional
study from the Tsurugaya Project1–3
Shinichi Kuriyama, Atsushi Hozawa, Kaori Ohmori, Taichi Shimazu, Toshifumi Matsui, Satoru Ebihara, Shuichi Awata,Ryoichi Nagatomi, Hiroyuki Arai, and Ichiro Tsuji
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
Objective: The objective was to examine the association between
green tea consumption and cognitive function in humans.
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 of28,26, and24 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) for3 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). Corresponding ORs were 1.00
(reference), 0.60 (95% CI: 0.35, 1.02), and 0.87 (95% CI: 0.55, 1.38)
(Pfor trend0.33) for black or oolong tea and 1.00 (reference), 1.16
(95% CI: 0.78, 1.73), and 1.03 (95% CI: 0.59, 1.80) (P for trend
0.70) for coffee. The results were essentially the same at cutoffs of
28 and 24.
Conclusion: A higher consumption of green tea is associated with a
lower prevalence of cognitive impairment in humans. AmJ Clin
Nutr 2006;83:355– 61.
KEY WORDS Cognitive function, elderly, green tea, Japanese,
Mini-Mental State Examination