The Effect of Acute Consumption of Beetroot Juice Supplement on Anaerobic Performance Indices in Trained Subjects: A Systematic Review and Meta-Analysis

Background and Purpose
Beetroot juice (BRJ) is rich in dietary nitrates (NO₃⁻) and has gained popularity for its potential ergogenic properties. Nitrates are converted to nitric oxide (NO) in the body, which enhances blood flow, oxygen delivery, and mitochondrial efficiency, potentially improving exercise performance. While BRJ has been extensively studied for its effects on aerobic performance, its impact on anaerobic performance—characterized by short-duration, high-intensity activities—remains less understood.
Anaerobic performance metrics, such as peak power, minimum power, mean anaerobic power, and fatigue index, are critical for athletes in sports requiring explosive strength and speed. Despite the growing interest in BRJ as a performance-enhancing supplement, there has been no systematic evaluation of its acute effects on anaerobic performance in trained individuals.
This study aims to systematically review and meta-analyze the existing literature to determine whether acute BRJ supplementation influences anaerobic performance indicators in trained subjects.
 
Materials and Methods
This research adhered to the PRISMA guidelines for systematic reviews and meta-analyses. Relevant articles in English and Persian were retrieved from databases including PubMed, Web of Science, Google Scholar, SID, and Magiran, up to September 2024. Eligibility criteria were as below:

Studies involving trained individuals.
Use of cross-over designs.
Reporting of anaerobic performance metrics (e.g., peak power, minimum power, mean anaerobic power, fatigue index).

Sample demographics (age, gender, BMI), type and dosage of BRJ supplementation, and anaerobic performance outcomes were extracted. A random-effects model was used to calculate standardized mean differences (SMD) and 95% confidence intervals (CIs). Heterogeneity was assessed using the I² statistic. Publication bias was evaluated through funnel plots and Egger's test.
 
Results
A total of 11 studies involving 140 participants (42 women and 98 men) met the inclusion criteria. The average age of participants ranged from 20.3 to 30.86 years, and BMI ranged from 20.41 to 24.21. Among them, Hassanpour et al. investigated both 70 mL and 140 mL doses of beetroot juice; Hashemifard et al. examined a 100 mL dose; and Conger et al. assessed a single dose of beetroot juice powder. Seven studies evaluated a 70 mL dose of beetroot juic. Tatlıcı and Cakmakci administered beetroot supplementation at a dose of 2 grams per kilogram of body weight, and Baumann examined beetroot juice in volumes ranging from 235 to 355 mL.
Five studies administered the supplement dose three hours prior to the experimental protocol, while three studies administered it two hours before the protocol. Additionally, Hashemi Fard et al. administered the dose 1.5 hours before the experimental protocol; Tatlici et al., 2.5 hours before; and Baumann et al., between 2.5 to 3 hours prior to the experimental procedure. Key results are as below:

Peak Power: [SMD = -0.109 (-0.33 to 0.11), P = 0.33], I²=32.703, P=0.12
Minimum Power: [SMD = -0.120 (-0.32 to -0.08)], P = 0.25, I²=0.00, P=0.53
Mean Anaerobic Power: [SMD = -0.134 (-0.30 to -0.03), P=0.13], I²=3.922, P=0.40
Fatigue Index: [SMD = -0.105 (-0.46 to -0.25), P=0.56], I²=53.807, P=0.04

Subgroup Analyses demonstrated that variations in BRJ consumption timing and dosage did not influence outcomes. Also, consistent results were observed across studies using standardized tests like the Wingate Anaerobic Test (WAnT) and Running-Based Anaerobic Sprint Test (RAST).
Heterogeneity was moderate to high (I² = 45–65%); and, funnel plots and Egger's test indicated no significant publication bias.
 
Conclusions
The findings suggest that acute BRJ supplementation does not significantly enhance anaerobic performance in trained individuals. While BRJ is rich in nitrates, which are known to improve blood flow and oxygen delivery, these effects may not translate to short-duration, high-intensity activities that rely primarily on anaerobic energy systems.
Duration of Activity: Anaerobic performance relies on immediate energy sources (e.g., ATP-PCr and glycolytic systems), which may not benefit significantly from increased NO availability.
Timing of Supplementation: Acute BRJ consumption may not provide sufficient time for nitrate conversion to NO and subsequent physiological effects.
Training Status: Trained individuals may already have optimized physiological adaptations, limiting the ergogenic potential of BRJ.
Unlike aerobic performance, which benefits from enhanced oxygen utilization and mitochondrial efficiency, anaerobic performance is less dependent on these mechanisms. This may explain the lack of significant effects observed in this study. The study had some limitations that may affect he results, included: Variability in study designs, BRJ dosages, and participant characteristics may have influenced results; The limited number of studies and participants may reduce the generalizability of findings; The review focused on acute effects, leaving the potential benefits of chronic BRJ supplementation unexplored.
Article Message
The findings of the present study indicate that acute beetroot supplementation cannot be considered a definitive strategy for enhancing anaerobic performance in trained individuals. Therefore, it is suggested that although trained individuals who are eager to benefit from the remarkable effects and therapeutic properties of beetroot—and athletes and coaches who, in line with the International Olympic Committee's position, seek to observe improvements in anaerobic performance and its related indices—may be interested in its use, the current evidence does not support the efficacy of acute supplementation in this population. It is likely that short-term or chronic supplementation protocols, administered over longer durations or at higher doses, may be required to achieve meaningful effects.
 Funding
The present meta-analysis did not receive funding from any organization.
Authors’ Contributions
All authors contributed to the design, execution, and writing of all sections of this study.
Conflict of Interest
The authors declare no conflict of interest.
Acknowledgement
We would like to thank the authors who provided the data of their studies