Green tea consumption and serum lipids and lipoproteins in a population of healthy workers in Japan.
OBJECTIVE
To examine the relation between green tea consumption and serum lipids and lipoproteins.


METHODS
The subjects were 13,916 workers (8476 men and 5440 women) aged 40-69 years at over 1000 workplaces in Nagano prefecture, central Japan. They underwent health screening offered by a single medical institute between April 1995 and March 1996 and did not have morbid conditions affecting serum cholesterol levels. Serum concentrations of total cholesterol, high-density lipoprotein (HDL) cholesterol and triglycerides were measured at the screening. The consumption of green tea and other life-style characteristics were ascertained by a questionnaire. The data were analyzed with multivariate linear model.


RESULTS
Daily consumption of green tea was reported by 86.7% of subjects. Green tea consumption was, statistically, significantly associated with lower levels of serum total cholesterol in both men and women while its associations with serum triglycerides and HDL cholesterol were not statistically significant. The inverse association of serum total cholesterol with green tea consumption appeared to level off at the consumption of more than 10 cups/day. Excluding the outlying subjects drinking more than 10 cups/day (0.4%), the regression analysis adjusting for age, body mass index, ethanol intake, smoking habit, coffee intake, and type of work showed that daily consumption of one cup of green tea was associated with a reduction in serum total cholesterol by 0.015 mmol/L (95% confidence interval 0.006 to 0.024, p < 0.001) in men and 0.015 mmol/L (0.004 to 0.025, p < 0.01) in women. After additional adjustment for selected dietary factors, the inverse association remained statistically significant; one cup of green tea per day was associated with a reduction in serum total cholesterol by 0.010 mmol/L (0.001 to 0.019, p = 0.03) in men and 0.012 mmol/L (0.001 to 0.022, p = 0.03) in women.


CONCLUSIONS
Consumption of green tea was associated with lower serum concentration of total cholesterol in Japanese healthy workers age 40-69 years; however, green tea consumption was unrelated to serum HDL-cholesterol and triglycerides.
Tokunaga
Shoji
S
Department of Preventive Medicine, Graduate School of Medical School of Medical Sciences, Kyushu University, Fukuoka, Japan. Toksan@phealth.med.kyushu-u.ac.jp
White
Ian R
IR
Frost
Chris
C
Tanaka
Keitaro
K
Kono
Suminori
S
Tokudome
Shinkan
S
Akamatsu
Takashi
T
Moriyama
Takeshi
T
Zakouji
Hidemoto
H
D000328:Adult; D000368:Aged; D000924:Anticholesteremic Agents / Q000494:pharmacology*; D028241:Camellia sinensis; D002392:Catechin / Q000494:pharmacology*; D008076:Cholesterol, HDL / Q000097:blood; D004032:Diet; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008019:Life Style; D008055:Lipids / Q000097:blood*; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D016272:Occupational Health / Q000706:statistics & numerical data; D013662:Tea; D014280:Triglycerides / Q000097:blood
D000924:Anticholesteremic Agents; D008076:Cholesterol, HDL; D008055:Lipids; D013662:Tea; D014280:Triglycerides; D002392:Catechin