Effects of grape juice consumption on oxidative stress and inflammation in male volleyball players: A randomized, double-blind, placebo-controlled clinical trial.

INTRODUCTION: Some foods are also demonstrated benefits, such as anti-inflammatory, antioxidant, and ergogenic activity, similar to that of sports supplements. Grape juice has been considered an important source of polyphenols and these compounds could promote positive effects to the sports players. In this sense, the objective was to evaluate the effects of purple grape juice consumption on indicators of oxidative stress, inflammation, muscle damage, global histone H4 acetylation levels, and muscle strength and muscle power in volleyball athletes. METHODS: This is a randomized double-blind clinical trial in which 12 male volleyball players (16 ± 0.6 years old) participated in three different moments with match simulation: control (without beverage) (WB), grape juice (GJ) and placebo (PLA) (400 mL/day of grape juice or placebo (maltodextrin) for 14 days in a cross-over model). Before and immediately after each match, blood collection for analysis of indicators of systemic redox status, systemic concentrations of Interferon-γ (IFN- γ) and Interleukin-4 (IL-4), muscle damage, by Creatine Kinase (CK-NAC) and levels of global histone H4 acetylation were performed, as well as handgrip strength (HG) and lower limb power tests. RESULTS: Consumption of grape juice significantly reduced lipid peroxidation (p = 0.04) and Deoxyribonucleic Acid (DNA) damage (p = 0.01) after the match. IFN-γ levels, IL-4, CK-NAC, and histone H4 acetylation post-match did not alter with the grape juice consumption. Lower limb power improved after acute exercise in WB and GJ conditions (p < 0.001). CONCLUSION: In this pilot trial, the intake of grape juice for two weeks seems to reduce the protein oxidation and DNA damage by intermittent physical exercise, without epigenetics influence.

Supplementation of Probiotics and Its Effects on Physically Active Individuals and Athletes: Systematic Review.

The aim of this study was to conduct a systematic review of the effects of probiotic supplementation on physically active individuals. The participants, interventions, comparisons, outcome and study design inclusion criteria were (a) studies involving healthy adults or older subjects of both sexes who did physical exercise (including athletes and physically active individuals), (b) interventions with probiotics, (c) inclusion of a control group, (d) outcomes not previously defined, and (e) clinical trials and randomized clinical trials, with no language or date restrictions. The search was conducted in the following scientific databases: MEDLINE, Embase, SciELO, Scopus, and Lilacs. Search terms were "Probiotics" OR "Prebiotics" OR "Microbiota" AND "Exercise" OR "Athletes." The articles were first screened by title and abstract by two independent reviewers and disagreements resolved by a third reviewer. Data were extracted independently by the same two reviewers; results were extracted in duplicate and then compared to avoid errors. A total of 544 articles were retrieved and 24 were included. A total of 1,680 patients were included, most of them being male (n = 1,134, 67.5%), with a mean age of 30.9 ± 6.1 years. Following probiotic supplementation, positive effects have been reported for several outcomes including respiratory tract infection, immunologic markers, and gastrointestinal symptoms in both athletes and nonathletes. However, published studies have distinct protocols and measured outcomes, and some of them have small sample size and failed to prove beneficial effect on probiotic supplementation, leading to inconclusive results for standardized supplementation protocols.