The Association Between Green Tea Intake and Metabolic Syndrome: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

Introduction: This review is the first to assess the effects of green tea on blood pressure, lipid profile, and glucose in people with metabolic syndrome, highlighting its potential anti-inflammatory and metabolic benefits.

Methods: We used Standardized Mean Differences (SMD) and Cohen's d for group comparisons, while heterogeneity and publication bias were assessed using the I² statistic, Cochrane Q test, Begg's funnel plot, and Egger's test.

Results: Our results showed that green tea consumption did not significantly affect FBS (SMD: -0.03; 95%; P = 0.95), HbA1C (SMD: 4.87; 95%; P = 0.63), systolic blood pressure (SMD: -0.42; 95%; P = 0.36), diastolic blood pressure (SMD: -0.24; 95%; P = 0.53), total cholesterol (SMD: -0.38; 95%; P = 0.19), TG (SMD: -0.17; 95%; P = 0.34), HDL-C (SMD: -0.07; 95%; P = 0.75), or LDL-C (SMD: -0.45; 95%; P = 0.25). Subgroup analyses showed that short-term green tea intake (<8 weeks) significantly reduced FBS (SMD: -1.62), total cholesterol (SMD: -1.09), TG (SMD: -0.74), and LDL-C (SMD: -0.83). Doses below 3000 mg/day were also linked to lower total cholesterol (SMD: -0.69) and LDL-C (SMD: -0.83). Among women, green tea improved total cholesterol (SMD: -0.79), HDL-C (SMD: 0.50), LDL-C (SMD: -1.25), and systolic blood pressure (SMD: -1.74), despite overall high heterogeneity and publication bias.

Conclusion: Although our results found no significant difference in the measurement factor in patients with MetS. subgroup analyses suggested potential benefits in women, those consuming lower doses (<3000 mg/day), and those with shorter intervention durations (<8 weeks).