抄録
Objective: To evaluate the effects of short-term consumption of a large amount of tea catechins on chromosomal damage, oxidative stress markers, serum lipid, folic acid, and total homocysteine levels in middle-aged healthy volunteers.
Methods: Forty volunteers (40-63 years) participated in a randomized, double-blind study. After a 1-week washout, the catechin group consumed approximately 1069 mg/day of total catechins for 1 week. The micronucleated binucleate cells (MNi) frequency in the cytokinesis-block micronucleus cytome assay, urinary 8-hydroxydeoxyguanosine (8-OHdG), isoprostane, lymphocyte and plasma vitamin C, serum lipid, folic acid, and total homocysteine levels were measured at the beginning and end of the intervention.
Results: No significant differences were observed between the catechin and placebo groups in terms of MNi frequency, urinary 8-OHdG, isoprostane, or lymphocyte and plasma vitamin C levels. The serum LDL-cholesterol level in the catechin group significantly decreased compared with pre-intervention period, and there was a decreased tendency in the catechin group compared with the placebo group, but the difference was not significant (P= 0.105). The serum folic acid level decreased (P= 0.073) and the total homocysteine level significantly increased in the catechin group (P= 0.029). No serious adverse events were observed during the study.
Conclusions: A large amount of tea catechins, which corresponds to approximately 10 cups of green tea per day for 1 week, seemed to be well tolerated, and did not influence chromosomal damage and the oxidative stress markers. Further long-term and large-scale studies are required to clarify the long-term effect of the consumption of a large amount of tea catechins on these markers as well as on improving dyslipidemia.
Trial Registration: ClinicalTrials. gov ID, NCT00448513
