Consumption of Pomegranate Juice Attenuates Exercise - Induced Oxidative Stress, Blood Pressure and Urinary Cortisol/Cortisone Ratio in Human Adults

Abstract

Background: Oxidative stress is exacerbated in overweight and obese individuals after acute exercise compared with their nonobese counterparts. Antioxidants supplementation of the diet may be one intervention to reduce exercise-induced oxidative stress in this vulnerable population. The aim of this study was to investigate whether polyphenol-rich pomegranate juice attenuates postexercise oxidative stress and contributors to oxidative stress (glucocorticoids) and blood pressure in healthy overweight subjects. Methods: Males and females participated in a randomized placebo controlled parallel pilot-study (mean BMI: 26.7 ± 6.6 kg/m2 ). Two groups of (n = 12) participants received either pomegranate pure juice (500 mL/day containing total polyphenols of 1685 mg GAE/L) or placebo (water matched for total energy) and all participants completed two standardized 30 min treadmill tests (50% Wmax) at baseline and after one week of the intervention. Results: Exercise induced lipid peroxidation (MDA) was lower following pomegranate juice consumption compared with placebo (31.2 ± 10.6 to 26.5 ± 9.8 MDA µmole/day) after 1 week (P = 0.035). Urinary free cortisol was reduced from 179.4 ± 53.2 to 125.6 ± 43.5 nmole/24h which was significant (p = 0.042). In addition, there was a statistically significant increase in urinary free cortisone: from 112.2 ± 40.4 to 187.6 ± 90.2 nmole/24 h (p = 0.045), and a significant decrease in the urinary free cortisol/cortisone ratio (p=0.009) from 1.6 ± 1.1 to 0.67 ± 0.55 following one week of pomegranate juice intake. Pomegranate juice consumption was also found to decrease systolic blood pressure pre-exercise (136.7 ± 11.7 to 131.8 ± 8.8 mmHg (p = 0.007), and post-exercise from 158.8 ± 15.8 to 148.1 ± 12.3 mmHg (p < 0.01) and diastolic blood pressure (86.3 ± 10.6 to 82.5 ± 6.8 mmHg (p = 0.04) and 103.1 ±12.5 to 93.9 ± 11.5 mmHg (p = 0.001), pre and post exercise, respectively. Correlation results between the change in Cortisol/cortisone ratio with the effect on blood pressure showed a negative significant association post pomegranate juice intake (p = 0.028 for systolic and p = 0,008 for diastolic BP). There were no changes in lipid peroxidation or blood pressure following placebo treatment. Conclusions: These findings suggest that pomegranate juice consumption prior to an acute bout of moderate intensity exercise can alleviate blood pressure and exercise-induced stress in the overweight and obese population.