This study examined whether beetroot juice (BTJ) would attenuate inflammation and muscle damage following a marathon. Using a double blind, independent group’s design, 34 runners(~16 previous marathons completed) consumed either BTJ or an isocaloric placebo (PLA) for3 days following a marathon. Maximal isometric voluntary contractions (MIVC),counter movement jumps (CMJ), muscle soreness, serum cytokines, leucocytosis, creatinekinase (CK), high sensitivity C-reactive protein (hs-CRP) and aspartate aminotransferase(AST) were measured pre, post, and on the 2 days after the marathon. CMJ and MIVC were reduced after the marathon (P<0.05) but no group differences were observed (P>0.05).Muscle soreness was increased in the day after the marathon (BTJ; 45±48 vs. PLA; 46±39mm) and had returned to baseline by day 2, irrespective of supplementation (P=0.694).Cytokines (Interleukin-6; IL-6, interleukin-8, tumour necrosis factor-α) were increased immediately post-marathon but apart from IL-6 had returned to baseline values by day 1 post.No interaction effects were evident for IL-6 (P=0.213). Leucocytes increased 1.7 fold after the race and remained elevated 2 days post, irrespective of supplement (P<0.0001). CKpeaked at 1 day post marathon (BTJ: 965±967 & PLA: 1141±979 IU·L-1) and like AST andhs-CRP, was still elevated 2 days after the marathon (P<0.05); however, no group differences were present for these variables. Beetroot juice did not attenuate inflammation or reduce muscle damage following a marathon, possibly because most of these indices were not markedly different from baseline values in the days after the marathon.
Clifford, T., Allerton, D. M., Brown, M. A., Harper, L., Horsburgh, S., Keane, K. M., Stevenson, E. J., & Howatson, G. (2017). Minimal muscle damage after a marathon and no influence of beetroot juice on inflammation and recovery. Applied Physiology, Nutrition and Metabolism, 42(3), 263-270. https://doi.org/10.1139/apnm-2016-0525