Beetroot juice and vitamin C co-supplementation enhances anaerobic performance and reduces post-exercise glycemia in wrestlers: a randomized, double-blind, placebo-controlled crossover trial.

BACKGROUND: Wrestling, characterized by high-intensity intermittent efforts, demands exceptional anaerobic power and recovery capacity. Nitrate-rich beetroot juice (BRJ), supplemented with vitamin C, has emerged as a potential ergogenic aid through increased nitric oxide bioavailability. However, limited data exists regarding its acute effects on anaerobic performance in combat sport athletes. This study investigated the acute effects of BRJ supplemented with vitamin C on upper- and lower-body anaerobic test performance and selected biochemical markers in collegiate wrestlers. METHODS: In a randomized, double-blind, placebo-controlled crossover trial, 28 collegiate male wrestlers (18–24 years) consumed a single 250-ml BRJ drink (8.4 mmol nitrate + 90 mg vitamin C) or an isocaloric nitrate-free placebo three hours prior to testing, with a 14-day washout between conditions. Participants performed sequential 30-second upper- and lower-body Wingate anaerobic test (WAnTs) separated by 90 s. Venous blood was collected pre-test, immediately post-test, and 24 h post-test and was analyzed for blood glucose, creatine kinase (CK), and lactate dehydrogenase (LDH). RESULTS: 24 completed the study. BRJ+vitamin C significantly increased upper-body WAnT peak power (419 ± 98 W vs. 403 ± 103 W, P < 0.001) and lower-body WAnT mean power (390 ± 89 W vs. 376 ± 89 W, P = 0.002) compared with placebo. Post-exercise blood glucose was significantly lower in the BRJ + vitamin C group (96.3 ± 19.2 mg/dl vs. 112.5 ± 20.4 mg/dl, P < 0.001). No significant differences were observed for CK (P = 0.59) or LDH (P = 0.27) at any measured time point. CONCLUSION: Acute BRJ + vitamin C supplementation improved anaerobic capacity and lowered post-exercise blood glucose in collegiate wrestlers, offering a potential ergogenic strategy for combat sports. Further studies with larger, diverse populations and chronic supplementation are needed to confirm and extend these findings. TRIAL REGISTRATION AND DATE: Iranian Registry of Clinical Trials (IRCT20240407061440N1); registration date: June 7, 2024.