Antioxidant Effect of a Probiotic Product on a Model of Oxidative Stress Induced by High-Intensity and Duration Physical Exercise

This randomized double-blind and controlled single-center clinical trial was designed to evaluate the effect of a 6-week intake of a probiotic product (1 capsule/day) vs. a placebo on an oxidative stress model of physical exercise (high intensity and duration) in male cyclists (probiotic group, n = 22; placebo, n = 21). This probiotic included three lyophilized strains (Bifidobacterium longum CECT 7347, Lactobacillus casei CECT 9104, and Lactobacillus rhamnosus CECT 8361). Study variables were urinary isoprostane, serum malondialdehyde (MDA), serum oxidized low-density lipoprotein (Ox-LDL), urinary 8-hydroxy-2 '-deoxiguanosine (8-OHdG), serum protein carbonyl, serum glutathione peroxidase (GPx), and serum superoxide dismutase (SOD). At 6 weeks, as compared with baseline, significant differences in 8-OHdG (Delta mean difference -10.9 (95% CI -14.5 to -7.3); p < 0.001), MDA (Delta mean difference -207.6 (95% CI -349.1 to -66.1; p < 0.05), and Ox-LDL (Delta mean difference -122.5 (95% CI -240 to -4.5); p < 0.05) were found in the probiotic group only. Serum GPx did not increase in the probiotic group, whereas the mean difference was significant in the placebo group (477.8 (95% CI 112.5 to 843.2); p < 0.05). These findings suggest an antioxidant effect of this probiotic on underlying interacting oxidative stress mechanisms and their modulation in healthy subjects. The study was registered in ClinicalTrials.gov (NCT03798821).

Automated summary

This study aimed to assess the impact of a 6-week intake of a probiotic product on an oxidative stress model of physical exercise in male cyclists. Results showed significant reductions in urinary 8-OHdG, serum MDA, and Ox-LDL in the probiotic group compared to placebo, suggesting an antioxidant effect on oxidative stress mechanisms in healthy subjects. Serum GPx did not increase in the probiotic group, while it significantly increased in the placebo group.