Effects of Dietary Nitrate Supplementation on Weightlifting Exercise Performance in Healthy Adults: A Systematic Review

Abstract

Dietary nitrate (NO3−) supplementation has been evidenced to induce an ergogenic effect in endurance and sprint-type exercise, which may be underpinned by enhanced muscle contractility and perfusion, particularly in type II muscle fibers. However, limited data are available to evaluate the ergogenic potential of NO3− supplementation during other exercise modalities that mandate type II fiber recruitment, such as weightlifting exercise (i.e., resistance exercise). In this systematic review, we examine the existing evidence basis for NO3− supplementation to improve muscular power, velocity of contraction, and muscular endurance during weightlifting exercise in healthy adults. We also discuss the potential mechanistic bases for any positive effects of NO3− supplementation on resistance exercise performance. Dialnet, Directory of Open Access Journals, Medline, Pubmed, Scielo, Scopus and SPORT Discus databases were searched for articles using the keywords: nitrate or beetroot and supplement or nut*r or diet and strength or “resistance exercise” or “resistance training” or “muscular power”. Four articles fulfilling the inclusion criteria were identified. Two of the four studies indicated that NO3− supplementation could increase aspects of upper body weightlifting exercise (i.e., bench press) performance (increases in mean power/velocity of contraction/number of repetitions to failure), whereas another study observed an increase in the number of repetitions to failure during lower limb weightlifting exercise (i.e., back squat). Although these preliminary observations are encouraging, further research is required for the ergogenic potential of NO3− supplementation on weightlifting exercise performance to be determined.

Effect of dietary nitrate on human muscle power: a systematic review and individual participant data meta-analysis

“…This is the first systematic review and meta-analysis evaluating the effects of dietary NO 3 − supplementation on maximal neuromuscular power in humans, and also the first individual participant data meta-analysis of the effects of dietary NO 3 − on any aspect of human performance. Our primary finding is that NO 3 − intake significantly enhances muscle power, thus supporting the conclusions of previous narrative reviews [14,17]. This effect was statistically independent of subject age or sex and was evident during both small and large muscle Fig.…”

“…The present meta-analysis lends quantitative support to previous narrative reviews [14,17] that have concluded that NO 3 − supplementation enhances maximal neuromuscular power in humans. Based on the currently available literature, this ergogenic effect is seemingly independent of subject age, sex, or the amount of muscle mass engaged in the activity but may be greater with acute vs. repeated dosing.…”

“…More recently, attention has shifted to the effects of dietary NO 3 − supplementation on performance during strength-or sprint-type activities, i.e., during brief skeletal muscle activity wherein aerobic ATP production is minimal. As recently reviewed by Alvares et al [13], dietary NO 3 − supplementation seems to have only a trivial impact on maximal force output during isometric or low velocity isotonic or isokinetic muscle contractions, although it may enhance the number of such repetitions that can be completed before failure [13,14]. Animal studies, however, have demonstrated that the primary effects of NO on the contractile properties of muscle are not on force but on speed, i.e., on the maximal velocity of shortening, and hence on maximal muscle power, i.e., the product of force and speed [15,16].…”

A Survey on Dietary Supplement Consumption in Amateur and Professional Rugby Players

“…Thus, supplementation with B-alanine increases muscle carnosine synthesis, favouring the regulation of the acid–base balance at the intramuscular level and enhancing muscle contractility [ 77 , 78 , 79 ]), its ergogenic effect on efforts with a high glycolytic component having been demonstrated [ 80 , 81 ], while sodium bicarbonate (due to an improvement in the regulation of extracellular pH and the consequent delay in fatigue) [ 82 , 83 ]) has an ergogenic effect in intermittent endurance tests [ 84 ] and muscular endurance [ 85 ]. On the other hand, supplementation with beet juice is a nutritional source rich in nitrate that can increase the bioavailability of nitric oxide, improving the performance of muscle strength [ 86 ], endurance capacity [ 87 ] and intermittent high- intensity efforts [ 88 ].…”

Effects of Nitrate Supplementation on Exercise Performance in Humans: A Narrative Review

“…Some research, however, focuses on investigating these effects on high-intensity exercise and strength, where mixed results are observed. Thompson et al (2016) − on upper body strength and the number of repetitions performed in upper body strength test (bench press) as well as lower body strength test (squat) [92]. We certainly need more research into the impact of NO 3 − on high-intensity exercise and strength, but preliminary results suggest that NO 3 − could be beneficial in this sport context as well.…”