Background: Hypertension, obesity and hyperlipidemia are key interlinked features of both metabolic syndrome and cardiovascular disease. Numerous studies have suggested that green tea may reduce blood pressure by activating endothelial nitric oxide synthase and reducing total cholesterol by disrupting the production of apo B and synthesis of chylomicrons and thus have cardio-protective effects. The aim of this pilot study was to investigate the effects of increasing the consumption of green tea-rich catechins on blood pressure (BP), total cholesterol and other body composition parameters in healthy volunteers living in Scotland.
Methods: Following a 2 day green tea free period, participants (n=12; 9 females and 3 males) were asked to drink 4 cups of green tea (organic Mao Jian Green Tea from the Zhejiang region of China) for 14 days (~800 ml green tea infusion containing 600800 mg total catechins). Fasting total plasma cholesterol, BP, weight, BMI and %body fat were measured at day 0 (baseline), day 7 and day 14.
Results: Mean systolic BP was reduced significantly by 7.1 mmHg (P<0.0001) and mean diastolic BP reduced by 7.8 mmHg over 14 days (P<0.0001). Mean fasting total cholesterol was reduced significantly by 0.556 mmol/l (P<0.008), BMI by 0.34 kg/m2 (P<0.001), body weight by 0.96 kg (P<0.001) and body fat by 2.36% (P<0.005).
Conclusion: Our results has shown that short term consumption of commercial green tea reduces systolic and diastolic BP, fasting total cholesterol, %body fat and body weight suggesting a role for green tea in decreasing established potential cardiovascular risk factors. This study also suggests that reductions may be more pronounced in the overweight population where a significant proportion are obese and have a high risk of cardiovascular disease. Green tea consumption is cost effective, accepted by patients and has no reported side effects.