Pomegranate Juice Consumption Influences Antioxidant Capacity, Total Phenolics, Glucocorticoid

Pomegranate juice consumption influences antioxidant capacity, total phenolics, glucocorticoid levels, blood pressure and exercise-induced oxidative stress in healthy volunteers by C Tsang1, G Good1, S Al Moosawi2and E A S Al-Dujaili1

1School of Health Sciences, Dietetics, Nutrition and Biological Sciences, Queen Margaret University, Edinburgh, UK, EH21-6UU, 2MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge, CB1 9NL

It is widely accepted that diet and exerciseare important factors in the prevention of cardiovascular disease1. Exercise induces the production of reactive oxygen species leading to tissue damage and lipid peroxidation. Pomegranate (Punica granatum L) provides a rich and varied source of polyphenolic compounds, and there is evidence that consumption of the fruit juice enhances antioxidant status, reduces blood pressure and improves insulin resistance2.The aim of this study is to investigate the effects of pomegranate juice consumption on blood pressure, lipid peroxidation, antioxidant status and urinary glucocorticoid levels before and after a moderate exercise bout. A randomized controlled study was conducted with20 healthy participants. Subjects attended two 30 minute treadmill exercise sessions (50% Wmax); pre and one week post pomegranate juice (500mL daily containing 842 mg total phenolics) or water consumption. 24 hour urine samples were collected after each exercise session. Blood pressure was monitored before and after each session. Antioxidant status, total phenolics, lipid peroxidation, free cortisol and cortisone levels were determined in all urine samples. Pomegranate juice consumption was found to significantly decrease systolic blood pressure (Pre-exercise: 147±20.7 to 138.1±17.3, p=0.007 and post-exercise:156.4±17.5 to 149.5±10.2mmHg, p=0.04), diastolic blood pressure (95.9 ±11.6 to 91.1±8.7, p=0.04 and 102.6±23.9 to 94.6±20.4mmHg, p=0.05) and levels of lipid peroxidation due to exercise (0.312 ±0.106 to 0.264 ±0.098 MDA mM/L, p=0.035). Antioxidant status and total phenolics were significantly enhanced following juice consumption (1.09±0.51 to 1.44±0.69 mM Fe2+, p=0.027; 673.75±302.9 to 872.2±413.6 mg/day gallic acid equivalents, p=0.041, respectively). There was no significant change in lipid peroxidation or blood pressure for subjects consuming water. Urinary free cortisol was reduced from 39.1 ±26.6 to 26.4 ±16.5 nmole/24h (p=0.064), however there was a statistically significant increase in urinary free cortisone (28.1 ±20.4 to 51.9 ±45.1 nmole/24h, p=0.045), and decrease in free cortisol/cortisone ratio (1.81 ±1.24 to 0.82 ±0.56, p=0.009). In conclusion, our results suggest that pomegranate juice enhances antioxidant status, reduces blood pressure and lipid peroxidation levels. Functional foods rich in polyphenols, such as pomegranate juice, may be beneficial in reducing blood pressure and exercise-induced oxidative stress as part of a healthy balanced diet.

1. Nanchahal, K, Morris, JN, Sullivan LM and Wilson PWF (2005). Coronary heart disease risk in men and the epidemic of overweight and obesity. International journal of obesity, 29, 317-320
2. Avriam, M & Dornfield, L (2000). PJ consumption inhibits serum angiotensin converting enzyme activity and reduces systolic blood pressure. Atherosclerosis 158 (1) 195-198.