The Effects of Green Tea on Serum Lipids, Antioxidants, and Coagulation Tests in Stable Coronary Artery Disease: a Prospective Interventional Study

IntroductionBrewed from the leaf of Camellia sinensis, which is derived from the family Theaceae, tea is the most common beverage in the world after water. It has various pharmacological effects. In this study, we investigated the effect of green tea on the paraclinical parameters of patients with chronic stable coronary artery disease. MethodsThis prospective, interventional study was conducted on 100 patients with known coronary artery disease, referred to our cardiac clinic. The diagnostic criteria were physical examination, electrocardiogram, exercise stress test, thallium scan, and coronary angiography where necessary. The patients consumed brewed green tea for one month (4g per day in 2 divided doses). Lipid levels, antioxidants, fibrinogen level, homocysteine level, prothrombin time (PT), partial thromboplastin time (PTT), bleeding time (BT), and clotting time (CT) were assayed before and after the consumption of green tea for the one month’s study period. The antioxidants of serum were measured with the ferric reduction antioxidation power (FRAP) method. PT, PTT, fibrinogen, and homocysteine were measured with the ELISA method. For the statistical analysis, the paired t-test was used. ResultsThe mean age (± SD) was 50.9 ± 9.2 years. The mean total cholesterol, LDL, triglycerides, and lipoprotein a (Lp–a) were decreased significantly after one month’s consumption of green tea (P< 0.001). Also, there was a significant decrease in fibrinogen and homocysteine levels. There was an increase in HDL and antioxidant levels after the consumption of green tea (P<0.001). In addition, average PT and PTT measurements were decreased significantly (P = 0.001 and P= 0.012, respectively). ConclusionRegular consumption of 4g/d green tea for one month had beneficial effects on serum lipid parameters and antioxidant levels (Iranian Heart Journal 2008; 9 (3):47 -52).