Effect of increased tea consumption on oxidative DNA damage among smokers: A randomized controlled study
Effect of increased tea consumption on oxidative DNA damage among smokers: A randomized controlled study
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DOI：
10.1093/jn/133.10.3303s
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发表时间：
2003-10-01
影响因子：
4.2
通讯作者：
Talbot, W
中科院分区：
文献类型：
--
作者：
Hakim, IA;Harris, RB;Talbot, W
饮茶与癌症和心脏病发病率降低有关。这些发现的一个潜在机制是茶多酚具有很强的抗氧化作用。一项II期随机对照茶饮干预试验旨在研究在4个月期间，大量饮用（每天4杯）无咖啡因绿茶或红茶对吸烟者尿液中8 - 羟基脱氧鸟苷（8 - OHdG）所衡量的氧化性DNA损伤的影响。共有143名年龄在18 - 79岁的重度吸烟者被随机分配饮用绿茶、红茶或水。每月测量血浆和尿液中儿茶素水平以及尿液中8 - OHdG的含量。143名吸烟者中共有133人完成了4个月的干预。采用多元线性回归模型来评估饮用绿茶和红茶对肌酐调整后的尿液8 - OHdG的主要影响以及交互作用，同时考虑或不考虑潜在混杂因素进行调整。与其他两组相比，绿茶组血浆和尿液中的儿茶素水平显著升高。在对基线测量值和其他潜在混杂因素进行调整后，对尿液8 - OHdG的评估显示，饮用无咖啡因绿茶4个月后，尿液8 - OHdG显著降低（-31%）（P = 0.002）。被分配到红茶组的吸烟者尿液8 - OHdG没有变化。这些数据表明，经常饮用绿茶可能保护吸烟者免受氧化损伤，并可能降低癌症风险或其他由吸烟相关自由基引起的疾病。
Tea drinking has been associated with decreased occurrence of cancer and heart disease. One potential mechanism for these findings is the strong antioxidant effect of tea polyphenols. A phase II randomized controlled tea intervention trial was designed to study the effect of high consumption (4 cups/d) of decaffeinated green or black tea on oxidative DNA damage as measured by urinary 8-hydroxydeoxyguanosine (8-OHdG) among smokers over a 4-mo period. A total of 143 heavy smokers, aged 18-79 y, were randomized to drink either green or black tea or water. Levels of plasma and urinary catechins and urinary 8-OHdG were measured monthly. A total of 133 of 143 smokers completed the 4-mo intervention. Multiple linear regression models were used to estimate the main effects and interaction effect of green and black tea consumption on creatinine-adjusted urinary 8-OHdG, with or without adjustment for potential confounders. Plasma and urinary levels of catechins rose significantly in the green tea group compared with the other two groups. Assessment of urinary 8-OHdG after adjustment for baseline measurements and other potential confounders revealed a highly significant decrease in urinary 8-OHdG (-31 %) after 4 mo of drinking decaffeinated green tea (P = 0.002). No change in urinary 8-OHdG was seen among smokers assigned to the black tea group. These data suggest that regular green tea drinking might protect smokers from oxidative damages and could reduce cancer risk or other diseases caused by free radicals associated with smoking.