A comparative study of the effect of green tea and sour tea on blood pressure and lipid profile in healthy adult men

BACKGROUND: Cardiovascular diseases (CVD) are a set of metabolic disorders affecting heart and blood vessels. Green tea and sour tea (Hibiscus sabdariffa L.) have attracted significant attention recently due to their high popularity, nutrient profile and therapeutic effects. The aim of the present study was to compare the effects of green tea and sour tea supplementation on blood pressure and lipid profile in healthy adult men. METHODS: This randomized, double-blind, placebo-controlled trial included 54 healthy adult men. The participants were randomly assigned to two intervention groups receiving 450 mg green tea or sour tea and one placebo group which consumed 450 mg placebo (maltodextrin) for 6 weeks. Blood pressure, lipid profile, dietary intake and physical activity were measured pre- and post-intervention and compared. RESULTS: After 6 weeks of intervention, sour tea supplementation led to a significant decrease in systolic blood pressure (SBP) compared with the placebo group. However, we faild to find any significant difference in SBP between green tea and control groups. Also, no significant changes were observed in diastolic blood pressure (DBP) and lipid profile between the three groups. In comparison with baseline, there was a significant increase in the mean level of serum high-density lipoprotein cholesterol (HDL-C) in green tea and sour tea groups. Also, the interventions resulted in significant decrease in the mean levels of serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) and DBP in the sour tea group compared with the pre-intervention value. CONCLUSION: On the basis of our findings, sour tea supplementation led to decreased SBP in healthy men compared with the placebo, but there was no significant difference between their effects on DBP and lipid profile.