Plain language summary
Yerba mate is a popular tea-like beverage, traditionally consumed in Latin and South America. Yerba mate contains a range of plant compounds that may have beneficial effects on health, such as weight loss and antioxidant activity. This study aimed to evaluate the effect of the intake of yerba mate and green tea on serum levels of leptin, a hormone involved in regulating appetite, and paraoxonase-1 (PON-1), an enzyme that can destroy harmful oxidised fats in the blood. 142 overweight or obese adults aged 35-60 years, with abnormal levels of fats in the blood and no history of coronary artery disease took part in this controlled, randomised clinical trial. Participants drank 1 litre of either yerba mate, green tea or apple tea daily for eight weeks. Blood PON-1 and leptin levels were measured at the beginning and end of the study. The group drinking yerba mate showed a significant 9.7% increase in blood levels of PON-1, but no difference in leptin levels. The consumption of green tea resulted in no significant differences in the levels of PON-1 or leptin. The increase in PON-1 levels in the yerba mate group was significantly associated with increased levels of high-density lipoprotein (HDL-c - often called ‘good’ cholesterol). The authors concluded that drinking yerba mate increased antioxidant capacity by increasing blood levels of PON-1 and was positively associated with increased HDL-c, demonstrating a protective role of this beverage against thickening and hardening of the arteries.
BACKGROUND This study aimed to evaluate the effect of the intake of yerba mate (YM) and green tea (GT) on serum levels of leptin and paraoxonase-1 (PON-1), compared to control. METHODS Controlled, randomized clinical trial (RCT) that evaluated 142 men and women affected by overweight or obesity aged 35-60 years, untreated dyslipidemia and no history of coronary artery disease. Participants were randomized to ingest 1000 mL GT, YM or apple tea (AT, control group) daily, during eight weeks. Serum PON-1 and leptin levels were analyzed by ELISA immunoassay at the beginning (baseline) and after eight weeks of intervention. RESULTS The intake of 1 l of YM/day resulted in significant increase in serum levels of PON-1 (9.7%; p = 0.005). The consumption of GT induced no significant difference in the levels of PON-1 (p = 0.154) and leptin (p = 0.783). Intergroup analysis showed a significant difference (p = 0.036) in the variation of PON-1 levels in the YM group when compared to GT and AT groups. In addition, the increase in PON-1 levels in the YM group was significantly associated with increased HDL-c (p = 0.004). CONCLUSIONS The intake of yerba mate increased the antioxidant capacity by increasing serum levels of PON-1 and was positively associated with increased HDL-c, stressing the protective role of this beverage against atherosclerotic diseases. GT intake had no significant effect on serum levels of PON-1 and leptin. TRIAL REGISTRATION This study is registered with ClinicalTrials.gov under protocol number NCT00933647.