Green tea consumption in everyday life and mental health.
OBJECTIVE
Green tea has been widely acknowledged in Japan to induce a pleasurable mental feeling. Recent laboratory studies have suggested positive psychological effects as a result of consuming green tea. The present study examined whether green tea consumption in everyday life in Japan is associated with positive mental health.


METHODS
A cross-sectional study was performed in February-March 2002.


METHODS
The subjects of the study consisted of a general population of 600 Japanese aged 20-69 years. Responses of 380 subjects, obtained by home-visit interview, were analysed. The questionnaire inquired about consumption of brewed green tea and other beverages, perceived mental health status, lifestyle and others. The 12-item General Health Questionnaire (GHQ 12) was used for the assessment of mental ill-health (GHQ score >or=4).


RESULTS
After adjustments for age, area, perceived mental stress, lifestyle and daily caffeine intake, the consumption of brewed green tea was not statistically associated with any decrease in risk of mental ill-health among either males or females (odds ratio (OR)=0.78, 95% confidence interval (CI)=0.47-1.29 for males; OR=0.77, 95% CI=0.51-1.14 for females). Daily caffeine intake (100 mg) inclusive of green tea, black tea, coffee and other caffeine-containing beverages was associated with a higher risk of mental ill-health among females (OR=1.26, 95% CI=1.01-1.56).


CONCLUSIONS
The results provide population-based evidence on the consumption of brewed green tea in everyday life and mental health, together with information on consumption patterns of various beverages and lifestyles.
Shimbo
Mari
M
Health Promotion/International Health, Division of Public Health, Graduate School of Tokyo Medical and Dental University, Yushima 1-5-45, Japan.
Nakamura
Keiko
K
Jing Shi
Hui
H
Kizuki
Masashi
M
Seino
Kaoruko
K
Inose
Tomoko
T
Takano
Takehito
T
D000328:Adult; D000368:Aged; D001628:Beverages; D002110:Caffeine / Q000008:administration & dosage* / Q000009:adverse effects; D003072:Cognition Disorders / Q000453:epidemiology*; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D006304:Health Status; D006801:Humans; D007564:Japan; D008019:Life Style; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D016017:Odds Ratio; D011594:Psychometrics; D012737:Sex Factors; D011795:Surveys and Questionnaires; D013662:Tea / Q000737:chemistry*
D013662:Tea; D002110:Caffeine