Mukamal Kenneth J, MacDermott Kristen, Vinson Joe A, Oyama Noriko, Manning Warren J, Mittleman Murray A
Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02446, USA.
Am Heart J. 2007 Oct;154(4):724.e1-6. doi: 10.1016/j.ahj.2007.07.008.
The effects of black tea consumption on cardiovascular risk factors have been inconsistent in previous randomized trials, all of which have been limited to a few weeks duration.
We conducted a pilot parallel-design randomized controlled trial among 31 adults aged 55 years and older with either diabetes or 2 other cardiovascular risk factors but no established clinical cardiovascular disease. Participants were randomized to drink 3 glasses daily of either a standardized black tea preparation or water for 6 months. Cardiovascular risk factors were measured at the beginning and conclusion of the study.
Three participants dropped out of the study, leaving 14 participants assigned to tea and 14 assigned to water eligible for analyses. We found no statistically significant effects of black tea on cardiovascular biomarkers, including lipids, inflammatory markers, hemoglobin, adhesion molecules, prothrombotic and fibrinolytic parameters, and lipoprotein oxidizability. Assignment to tea did not appreciably influence blood pressure, and heart rate among participants assigned to tea was marginally higher than among control participants at 3 months (P = .07) but not 6 months.
In this randomized trial of black tea intake over 6 months among older adults with known cardiovascular risk factors, black tea did not appreciably influence any traditional or novel biomarkers of cardiovascular risk. Longer randomized trials are needed to verify the inverse association of tea with risk of cardiovascular disease seen in cohort studies and identify potential candidate mechanisms for such an association.
在以往的随机试验中，饮用红茶对心血管危险因素的影响并不一致，且所有试验的持续时间都限制在几周内。
我们在31名55岁及以上患有糖尿病或其他两种心血管危险因素但无确诊临床心血管疾病的成年人中进行了一项平行设计的随机对照试验。参与者被随机分为两组，一组每天饮用3杯标准化红茶制剂，另一组每天饮用3杯水，为期6个月。在研究开始和结束时测量心血管危险因素。
3名参与者退出研究，剩余14名分配到红茶组和14名分配到水组的参与者符合分析条件。我们发现红茶对心血管生物标志物没有统计学上的显著影响，这些生物标志物包括血脂、炎症标志物、血红蛋白、黏附分子、血栓前和纤溶参数以及脂蛋白氧化能力。分配到红茶组对血压没有明显影响，在3个月时，分配到红茶组的参与者的心率略高于对照组参与者（P = 0.07），但在6个月时没有差异。
在这项针对有已知心血管危险因素的老年人进行的为期6个月的红茶摄入随机试验中，红茶对任何传统或新型心血管风险生物标志物均无明显影响。需要进行更长时间的随机试验来验证队列研究中观察到的茶与心血管疾病风险之间的负相关关系，并确定这种关联的潜在候选机制。
