Effects of natural polyphenol-rich pomegranate juice supplementation on plasma ion and lipid profiles following resistance exercise: a placebo-controlled trial

Background: Pomegranate juice (POMj) contains abundant soluble polyphenolic antioxidant compounds and is recommended for its cardioprotective/atheroprotective properties. However, very few studies have investigated the efficacy of POMj supplementation to alter physiological responses during intensive physical exercise. This placebo-controlled study aimed to examine whether supplementation with natural polyphenol-rich-POMj could influence the ionic or lipid responses to an intensive resistance training session in elite athletes. Methods: Nine elite weightlifters (21 ± 1 years) performed two Olympic-weightlifting sessions after ingesting placebo and POMj supplements. Venous blood samples were collected at rest and 3 min after each session for assessment of plasma sodium ([Na⁺]), potassium ([K⁺]), chloride ([Cl^-]), calcium ([Ca²⁺]), triglyceride ([TG]) and high-density lipoprotein ([HDL-C]), low-density lipoprotein ([HDL-C]) and total ([TC]) cholesterol concentrations. Results: Plasma [K⁺] and [TG] were lowered post-exercise compared to resting values in the PLA condition (p = 0.03 for K⁺ and p = 0.02 for TG) with no pre-to-post exercise differences in the other plasma ion and lipid markers (p > 0.05). Compared to rest, plasma [Na⁺] and [Cl^-] were increased (p = 0.04, %change = 4.10% for Na⁺ and p = 0.02, %change = 4.44% for Cl^-), but there were no differences in the other plasma ion or lipid markers post-exercise after POMj supplementation (p > 0.05). Post-exercise plasma [Na⁺], [Cl^-], and [HDL-C] were greater following POMj supplementation compared to PLA (p = 0.01 for Cl-A nd HDL-C, p = 0.02 for Na+, and p = 0.04 for TC), with no between-supplement post-exercise differences in the other ion and lipid markers (p > 0.05). Conclusion: In conclusion, supplementation with POMj has the potential to attenuate the acute imbalance of plasma [K⁺] and to improve blood lipid responses (i.e., HDL-C) following resistance exercises in elite weightlifters. However, further large research in both athletic and non-athletic populations is needed to corroborate these preliminary observations and to elucidate the potential underlying mechanisms and translational potential of our novel observations. Trial registration: Name of the registry: ClinicalTrials.gov PRS The registration number: NCT02697903. Date of Registry: 03/03/2016 'Retrospectively registered'. The registration title: Pomegranate Improve Biological Recovery Kinetics in Elite Weightlifter. Graphical abstract: [Figure not available: See fulltext.]