Relation of green tea consumption to serum lipids and lipoproteins in Japanese men.

Animal experiments have shown a hypocholesterolemic effect of green tea extracts. Only few epidemiological studies have addressed the relation between green tea consumption and serum total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C). This paper examined the relation of green tea consumption to serum lipids and lipoproteins in 2,062 male self-defense officials in Japan, aged 49-55 years, who received a preretirement health examination at three hospitals of the Self-Defense Forces in 1991-1992. A self-administered questionnaire queried the consumption of green tea and a limited number of other dietary items as well as lifestyle characteristics. After adjustment for body mass index, waist-hip ratio, smoking, alcohol use, exercise, rank, and hospital, green tea consumption was inversely associated with serum levels of TC and LDL-C, but not with either high density lipoprotein cholesterol or triglycerides. Rice consumption was positively correlated with green tea consumption, and also was associated independently with lower levels of TC and LDL-C. Additional adjustment for rice, however, did not change the results. Daily drinking of 10 cups of green tea was associated with differences of 6.2 mg/dl in TC (95% confidence interval [CI] 0.4-12.1) and 6.2 mg/dl in LDL-C (95% CI 0.7-11.7). These findings of association of green tea with blood cholesterol hint at a possible causal relationship, which requires confirmation by further studies in humans using different methods.