Dietary nitrate supplements and nitrate-rich foods are considered 'Group A' performance enhancing supplements by the Australian Institute of Sport due to strong evidence backing their potential to boost athletic performance and permitted use in many sports.
A meta-analysis of 80 randomised placebo-controlled trials (RCTs) involving 1300 participants revealed statistically significant, measurable and repeatable improvements in exercise performance when used by active, young, healthy men and highly trained athletes. The performance-enhancing effects of beetroot juice are attributed to the nitrate content which enhances the effects of Nitric Oxide and is shown to help regulate blood pressure, blood flow, muscle contraction and immune function.
Evidence suggests the benefit is mostly seen when ingesting nitrate-rich foods (e.g. 200mL beetroot juice), around 2 to 3.5 hours before exercise such as cycling and running events of 4 to 30 minutes duration, as well as team sports involving intermittent exercise.
According to the robust findings of this study, the performance-enhancing effects of dietary nitrate and beetroot juice might be highly meaningful to athletes looking to enhance performance, especially in participants with excellent aerobic fitness that have already optimised other training parameters.
References:
1. Group A Supplements [Internet]. Sport Australia. 2021 [cited 19 May 2021]. Available from: https://www.ais.gov.au/nutrition/supplements/group_a
2. SENEFELD, J., WIGGINS, C., REGIMBAL, R., DOMINELLI, P., BAKER, S., & JOYNER, M. (2020). Ergogenic Effect of Nitrate Supplementation: A Systematic Review and Meta-analysis. Medicine and Science in Sports and Exercise, 52(10), 2250-2261. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7494956/