Objective
Green tea (Camellia sinensis) has shown to exert cardio-protective benefits in observational studies. The objective of this clinical trial was to assess the effects of green tea on features of metabolic syndrome and inflammation in obese subjects.
Methods
We conducted a randomized controlled trial in obese subjects with metabolic syndrome. Thirty-five subjects [age (mean±SE) 42.5±1.7 years, BMI 36.1±1.3 kg/m2] completed the 8-week study and were randomly assigned to receive green tea (4 cups/day), green tea extract (2 capsules and 4 cups water/day), or no treatment (4 cups water/day). Both the beverage and extract groups had similar dosing of epigallocatechin-3-gallate (EGCG), the active green tea polyphenol. Fasting blood samples were collected at screening, four, and eight weeks of the study.
Results
Green tea beverage or extract supplementation did not significantly alter features of metabolic syndrome or biomarkers of inflammation including adiponectin, C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-1β (IL-1β), soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1), leptin, or leptin:adiponectin ratio. However, both green tea beverage and extracts significantly reduced plasma serum amyloid alpha (SAA) versus no treatment (p<0.005).
Conclusion
This study suggests that the daily consumption of green tea beverage or extracts for 8 weeks was well tolerated but did not affect the features of metabolic syndrome. However, green tea significantly reduced plasma SAA, an independent CVD risk factor, in obese subjects with metabolic syndrome.