ABSTRACT
BACKGROUND: We examined the influence of superoxide dismutase 3 (SOD3) Arg213Gly and Peroxisome Proliferator-Activated α-Receptor (PPARα) 7G/C polymorphisms to a single dose of purple grape juice supplementation on time-to-exhaustion running test, redox balance and muscle damage in recreational runners. METHODS: Forty-seven male recreational runners performed a running test until exhaustion after supplementation with grape juice or a control drink. Serum total antioxidant capacity (TAC), malondialdehyde (MDA), plasma nitrite (NO), creatine kinase (CK) and lactate dehydrogenase (LDH) were measured pre and post exercise. Also, polymorphisms were analyzed in DNA extracted from the oral mucosa. RESULTS: Grape juice improved the time-to-exhaustion. When analyzed by genotype, the recreational runners with GG+CG genotypes of the SOD3 gene had greater time-to-exhaustion than the CC genotype, but was no different for the PAPRα gene. A slight difference was noted in TAC, since the CC genotype of the SOD3 gene showed higher TAC values in the post-exercise compared to the baseline and with pre-exercise, but these values did not increase compared to the CG+GG group, respectively. The SOD3 and PPARα genes were similar at all times for the other biochemical variables. CONCLUSION: The ergogenic effect of grape juice was genotype-dependent for SOD3 Arg213Gly. However, biochemical redox balance markers did not explain this difference.
ABSTRACT
PURPOSE: To investigate the effects of a single dose of juice on physical performance, oxidative stress, inflammation and muscle damage in runners. METHODS: Fourteen recreational male runners (39 ± 9 years, VO2peak = 55.9 ± 6.5 ml/kg/min) performed two running tests to exhaustion at 80% of VO2max after ingesting grape juice or a placebo drink (10 ml/kg/day) randomly. Blood samples were taken before and 2 h after supplementation and immediately after running to analyze total antioxidant capacity (TAC), malondialdehyde (MDA), alpha-1 acid glycoprotein (A1GPA), high-sensitivity C-reactive protein (hs-CRP), creatine kinase (CK) and lactate dehydrogenase (LDH). RESULTS: The participants ran for an average of 59.2 ± 27.8 min until exhaustion in the placebo group and for 68.4 ± 29.7 min until exhaustion in the grape juice intake group, which was a significantly longer time (p = 0.008). This improvement in physical performance was accompanied by a 43.6% increase in TAC (p = 0.000) at the post-exercise timepoint compared to the level at baseline. MDA, A1GPA, hs-CRP, CK, and LDH did not exhibit changes. In contrast, no significant change in any variable was observed after consuming the placebo drink. CONCLUSION: The single-dose intake of purple grape juice demonstrated an ergogenic effect in recreational runners by increasing run time to exhaustion and increasing antioxidant activity.
