Effects of pomegranate juice in circulating parameters, cytokines, and oxidative stress markers in endurance-based athletes: A randomized controlled trial

Abstract

Objective: The aim of the present study was to assess the effects of pomegranate juice on the level of oxidative stress in the blood of endurance-based athletes. Pomegranate juice is rich in polyphenols, conferring it a higher antioxidant capacity than other beverages with polyphenolic antioxidants. Methods: A randomized double-blind, multicenter trial was performed in athletes from three different sport clubs located in southeastern of Spain. Plasma oxidative stress markers (protein carbonyls and malondialdehyde [MDA]) as well as C-reactive protein and sE-selectin were measured. Thirty-one athletes participated in the study. Participants were divided into three groups. The first group was supplemented with 200 mL/d pomegranate juice (PJ; n = 10) over a 21-d period, the second with 200 mL/d pomegranate juice diluted 1:1 with water (PJD; n = 11), and a control group that did not consume pomegranate juice (C; n = 10). Nine athletes were excluded due to protocol violations (n = 4 in the PJ group and n = 5 in the PJD group) because they did not observe the 24 h of rest before the last blood test. Results: The control group increased levels of carbonyls (+0.7 ± 0.3 nmols/mg protein) and MDA (+3.2 ± 1.0 nmols/g protein), whereas the PJ and PJD groups maintained or decreased their levels, respectively. On the other hand, lactate levels increased in the PJ group (from 10.3 at day 0 to 21.2 mg/dL at day 22). A nonsignificant decrease was detected in sE-selectin and C-reactive protein in the groups consuming pomegranate juice. Conclusion: Consumption of pomegranate juice over a 21-d period improved MDA levels and carbonyls, and thus decreased the oxidative damage caused by exercise.