Effects Of Dietary Nitrate Supplementation Research Articles

Effects of Dietary Nitrate Supplementation on Physical Performance and Muscle Strength in Older People—A Systematic Review

Effects of Dietary Nitrate Supplementation on Physical Performance and Muscle Strength in Older People—A Systematic Review

Effects of Dietary Nitrate Supplementation on High-Intensity Cycling Sprint Performance in Recreationally Active Adults: A Systematic Review and Meta-Analysis.

This systematic review and meta-analysis investigated the influence of dietary nitrate supplementation on performance metrics during cycling sprint exercise according to the PRISMA guidelines. Searches were conducted on MEDLINE, PubMed, ScienceDirect, Scopus, and SPORTDiscus databases up to September 2023. Inclusion criteria were healthy recreationally active men and women who consumed nitrate-rich and nitrate-deficient beetroot juice to assess performance outcomes of mean power, peak power, time-to-peak power, and minimum power during 30-s cycling sprints. Risk of bias was assessed using the Cochrane Risk of Bias 2 and TESTEX tools and funnel plots. A random effects model was performed on six studies and showed that dietary nitrate had significant effects on time-to-peak power (SMD: -0.66, 95% CI: -1.127 to -0.192, p = 0.006) but not on mean power, peak power, or minimum power. Subgroup analysis revealed that an acute low nitrate dose improved time-to-peak power (SMD: -0.977, 95% CI: -1.524 to -0.430, p < 0.001) but not after a multiday moderate nitrate dose (SMD: -0.177, 95% CI: -0.619 to -0.264, p = 0.431). These data suggest that acute nitrate supplementation can benefit time-to-peak power during 30-s cycling sprints, but due to the limited availability of data and heterogeneity in methodology, these results should be interpreted with caution. There was insufficient data on women to analyze sex-based differences. Future studies are required to provide insight on how supplementation regimen and population impact the effects of dietary nitrate for enhancing cycling sprint performance.

The acute effects of dietary nitrate supplementation on postmenopausal endothelial resistance to ischemia reperfusion injury: a randomized, placebo-controlled, double blind, crossover clinical trial.

Postmenopausal cardiovascular health is a critical determinant of longevity. Consumption of beetroot juice (BR) and other nitrate-rich foods is a safe, effective non-pharmaceutical intervention to increase systemic bioavailability of the vasoprotective molecule, nitric oxide, through the exogenous nitrate (NO3 -)-nitrite (NO2 -)-nitric oxide (NO) pathway. We hypothesized that a single dose of nitrate-rich beetroot juice (BRnitrate 600 mg NO3 -/140 mL, BRplacebo ∼ 0 mg/140 mL) would improve resting endothelial function and resistance to ischemia-reperfusion (IR) injury to a greater extent in early-postmenopausal (1-6 years following their final menstrual period (FMP), n=12) compared to late-postmenopausal (6+years after FMP, n=12) women. Analyses with general linear models revealed a significant (p<0.05) time*treatment interaction effect for brachial artery adjusted flow-mediated dilation (FMD). Pairwise comparisons revealed that adjusted FMD was significantly lower following IR-injury in comparison to all other time points with BRplacebo (early FMD 2.51±1.18%, late FMD 1.30±1.10, p<0.001) and was lower than post-IR with BRnitrate (early FMD 3.84±1.21%, late FMD 3.21±1.13%, p=0.014). A single dose of BRnitrate significantly increased resting macrovascular function in the late postmenopausal group only (p=0.005). Considering the postmenopausal stage-dependent variations in endothelial responsiveness to dietary nitrate, we predict differing mechanisms underpin macrovascular protection against IR injury.

Effects of dietary nitrate supplementation on markers of oral health: A systematic review

The oral cavity is a vital part of the digestive system. Poor oral health can impact an individual’s ability to eat and has been associated with increased risk of non-communicable diseases and reduced longevity. Conversely, positive oral health has been associated with improved cardiometabolic, cognitive and systemic health and greater longevity. Consumption of dietary nitrate, which is processed in the mouth into nitrite, and is subsequently converted into nitric oxide (NO) in the body (1), has been demonstrated to reduce blood pressure, improve endothelial function, and enhance exercise performance. Interestingly, recent studies suggest that nitrate consumption could also positively modulate markers of oral health (2). To our knowledge, no systematic review has been published examining the effect of inorganic dietary nitrate on oral health. However, this could be valuable to summarise current state of the knowledge, identify effect modifiers and highlight gaps for future research. Therefore, this systematic review aims to investigate the effects of dietary nitrate supplements on markers of oral health in vivo in randomised controlled trials (RCTs).This study was pre-registered with PROSPERO (CRD42023411159). Five databases (PubMed, The Cochrane Library, CINAHL, MEDLINE, and SPORTDiscus) were searched from inception until March 2023 to identify studies that met the following criteria: adult participants (≥ 18 years) and RCTs investigating the effects of oral dietary nitrate versus placebo on markers of oral health. A narrative synthesis of data was conducted. Risk of bias was assessed using the Cochrane Risk of Bias 2 tool.Nine articles reporting data on 284 participants were included. Nitrate was provided via beetroot juice (six studies), a beetroot-derived supplement dissolved in mineral water (one study), and lettuce juice (two studies). The duration of the interventions ranged from one day to a maximum of six weeks. Dietary nitrate supplementation increased the relative abundance of several individual bacterial genera including Neisseria (increased in three studies) and Rothia (increased in three studies). Dietary nitrate supplementation increased salivary pH (increased in two studies) and decreased salivary acidification resulting from the consumption of a sugar-sweetened beverage (decreased in two studies). Furthermore, dietary nitrate supplementation resulted in a decrease in the gingival inflammation index in one study. Overall, the risk of bias in studies was mixed. One study had a low risk of bias, while the rest were rated as having some concerns. No study was considered to have a high risk of bias.The results show that dietary nitrate is a potential nutritional strategy that can potentially benefit oral health by modifying the oral microbiome, altering salivary pH, and minimising gingival inflammation.

Can the dietary inorganic nitrate supplementation mitigate the vascular dysfunction in elderly with Alzheimer’s disease?

Aging and Alzheimer disease (AD) are both characterized by progressive reduction in nitric oxide bioavailability and endothelial function impairment. Promising studies on young healthy individuals underly the positive effect of dietary nitrate supplementation on endothelial function. However, the pharmacokinetics of the plasma nitrate and nitrite (PN) and the accompanying endothelial responsiveness following the oral nitrate ingestion in healthy elderly (HE) and patients with AD is not clear. Our hypothesis was that due to the reduction of nitric oxide bioavailability during aging and AD, an equal dose of oral nitrate (ON) would ameliorate the endothelial responsiveness more in the HE and even more in patients with AD in comparison to healthy young subjects (HY). Therefore, with the aim of investigating the pharmacokinetics of PN and the time-course endothelial responsiveness in response to a single dose ON, 10 HY (25±4 YRS), 10 HE (72±8 YRS) and 13 AD (73±7 YRS) were recruited. PN levels and endothelial responsiveness (single-passive leg movement (ΔPLM)) were measured in the recruited individuals prior to (T0) and hourly for 4 hours (T1, T2, T3, and T4) after: a) a single dose of ON; and b) a single dose of placebo. As expected at T0 both PN and ΔPLM were significantly reduced in the HE and even more reduced in the AD in comparison to the HY (all p&lt;0.001). No changes in PN nor ΔPLM were detected in any group following placebo intake. PN increased significantly in all three groups at T1 (p&lt;0.001) and constantly increased up to T4, but no differences were detected between time points T1 to T4 in any group. ΔPLM increased significantly in all three groups at T2, reaching highest values at T4 (p&lt;0.001). However, AD exhibited significantly lower ΔPLM values at any time point compared to HY (p&lt;0.0001) and HE (p&lt;0.001). Significant correlation between PN and ΔPLM was found (p&lt;0.001, R2=0.1654). Contrary to our hypothesis, the results of this study suggest that the PN pharmacokinetics following a single dose of ON is similar in HY, HE and AD. Moreover, the expected time-course amelioration of the endothelial responsiveness was reduced in the HE and even more reduced in the AD, suggesting that other factors, rather than the nitric oxide bioavailability, are playing a role in the age- and AD-related vascular dysfunction. Ricerca di Base 2017 - RBVR17XRSA - Effectiveness of exercise and nitrate supplementation on progression of dementia in patients with Alzheimer’s disease. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

357 Effects of Dietary Nitrate Supplementation on Vascular Function in Individuals with Prediabetes

OBJECTIVES/GOALS: Impaired vascular function, a subclinical marker of cardiovascular disease, has been identified in prediabetes. Dietary nitrate supplementation has been shown to improve vascular function. However, this has not been studied in prediabetes. The purpose was to determine the effects of dietary nitrate on vascular function in prediabetes. METHODS/STUDY POPULATION: Five individuals with prediabetes (4 men, 1 woman; 55 ± 17 yr; HbA1c = 5.8 ± 0.2) participated in a double-blind, placebo-controlled, repeated measures study. Participants were randomly assigned to a 3-day nitrate supplementation (nitrate-rich beetroot juice, 12.9 mmol, 140 mL), or a placebo supplementation (nitrate-depleted beetroot juice, 0.05 mmol, 140 mL). Following supplementation, participants reported to the lab for measures of vascular function in the lower limb. Doppler ultrasonography was used to measure flow-mediated dilation (FMD) and post-occlusive reactive hyperemia (RH) of the superficial femoral artery in response to a 5-min bout of leg ischemia. RESULTS/ANTICIPATED RESULTS: FMD did not differ between the nitrate-rich (2.87 ± 2.01%) and placebo (2.24 ± 1.69%) conditions (p = 0.48; d = 0.35). Furthermore, peak RH did not differ between the nitrate-rich (1503 ± 443 ml/min) and placebo (1762 ± 414 ml/min) conditions (p = 0.36; d = 0.46). DISCUSSION/SIGNIFICANCE: These preliminary results suggest that dietary nitrate supplementation in the form of beetroot juice does not improve vascular function in individuals with prediabetes.

Corrigendum to “Effects of dietary nitrate supplementation on peak power output: Influence of supplementation strategy and population” [Nitric Oxide 136-137C (2023) 33–47

Corrigendum to “Effects of dietary nitrate supplementation on peak power output: Influence of supplementation strategy and population” [Nitric Oxide 136-137C (2023) 33–47

Effects of Dietary Nitrate Supplementation on Performance during Single and Repeated Bouts of Short-Duration High-Intensity Exercise: A Systematic Review and Meta-Analysis of Randomised Controlled Trials.

Inorganic nitrate (NO3-) has emerged as a potential ergogenic aid over the last couple of decades. While recent systematic reviews and meta-analyses have suggested some small positive effects of NO3- supplementation on performance across a range of exercise tasks, the effect of NO3- supplementation on performance during single and repeated bouts of short-duration, high-intensity exercise is unclear. This review was conducted following PRISMA guidelines. MEDLINE and SPORTDiscus were searched from inception to January 2023. A paired analysis model for cross-over trials was incorporated to perform a random effects meta-analysis for each performance outcome and to generate standardized mean differences (SMD) between the NO3- and placebo supplementation conditions. The systematic review and meta-analysis included 27 and 23 studies, respectively. Time to reach peak power (SMD: 0.75, p = 0.02), mean power output (SMD: 0.20, p = 0.02), and total distance covered in the Yo-Yo intermittent recovery level 1 test (SMD: 0.17, p < 0.0001) were all improved after NO3- supplementation. Dietary NO3- supplementation had small positive effects on some performance outcomes during single and repeated bouts of high-intensity exercise. Therefore, athletes competing in sports requiring single or repeated bouts of high-intensity exercise may benefit from NO3- supplementation.

Effects of Dietary Nitrate Supplementation on Back Squat and Bench Press Performance: A Systematic Review and Meta-Analysis.

This systematic review and meta-analysis investigated the influence of dietary nitrate supplementation on resistance exercise performance according to the PRISMA guidelines. Searches were conducted on MEDLINE, PubMed, ScienceDirect, Scopus and SPORTDiscus databases up to April 2023. Inclusion criteria were adult resistance-trained males who supplemented with a nitrate-rich supplement and nitrate-deficient placebo to assess repetitions-to-failure (RTF), peak power, mean power, peak velocity, and/or mean velocity during back squat and bench press exercise. A random effects model was performed on six studies and showed that nitrate supplementation improved RTF (standardized mean difference [SMD]: 0.43, 95% confidence intervals [95% CI]: 0.156 to 0.699, p = 0.002), mean power (SMD: 0.40, 95% CI: 0.127 to 0.678, p = 0.004), and mean velocity (SMD: 0.57, 95% CI: 0.07 to 1.061, p = 0.025) but had no effect on peak power (SMD: 0.204, 95% CI: -0.004 to 0.411, p = 0.054) or peak velocity (SMD: 0.00, 95% CI: -0.173 to 0.173, p = 1.000) when back squat and bench press were combined. Subgroup analyses revealed that back squats were more likely to be enhanced and that a dosing regimen may influence the efficacy of nitrate supplementation. Overall, nitrate supplementation had a small beneficial effect on some aspects of resistance exercise performance, but there were limited studies available and the variability was large. Additional studies that focus on upper and lower body resistance exercise and nitrate dosage are required to elucidate the efficacy of dietary nitrate supplementation on resistance exercise performance.

Effects of Dietary Nitrate Supplementation on Performance and Muscle Oxygenation during Resistance Exercise in Men.

The purpose of the current study was to assess the effects of acute and short-term nitrate (NO3−)-rich beetroot juice (BR) supplementation on performance outcomes and muscle oxygenation during bench press and back squat exercise. Fourteen recreationally active males were assigned in a randomized, double-blind, crossover design to supplement for 4 days in two conditions: (1) NO3−-depleted beetroot juice (PL; 0.10 mmol NO3− per day) and (2) BR (11.8 mmol NO3− per day). On days 1 and 4 of the supplementation periods, participants completed 2 sets of 2 × 70%1RM interspersed by 2 min of recovery, followed by one set of repetitions-to-failure (RTF) at 60%1RM for the determination of muscular power, velocity, and endurance. Quadriceps and pectoralis major tissue saturation index (TSI) were measured throughout exercise. Plasma [NO3−] and nitrite ([NO2−]) were higher after 1 and 4 days of supplementation with BR compared to PL (p < 0.05). Quadriceps and pectoralis major TSI were not different between conditions (p > 0.05). The number of RTF in bench press was 5% greater after acute BR ingestion compared to PL (PL: 23 ± 4 vs. BR: 24 ± 5, p < 0.05). There were no differences between BR and PL for RTF for back squat or power and velocity for back squat or bench press (p > 0.05). These data improve understanding on the ergogenic potential of BR supplementation during resistance exercise.

Dietary nitrate, aging and brain health: the latest evidence.

With an increasing population age, cognitive decline and age-associated neurodegenerative diseases are becoming increasingly prevalent and burdensome in society. Dietary supplementation with inorganic nitrate, which serves as a nitric oxide precursor, has been suggested as a potential nutritional strategy to improve brain health in older adults. In this review, we discuss recent findings in this area. A number of studies have emerged in the past 12-18 months exploring the effects of dietary nitrate supplementation on cognitive function, with typically (although not exclusively) null findings emerging. This research is characterized by small, acute/short-term studies, although observational studies and longer-duration randomised controlled trials are beginning to emerge. From the limited research reporting benefits of nitrate supplementation on cognitive function, one important discovery has been the identification of a potential pathway through which nitrate could impact cognitive health, involving modulation of the oral microbiome, which warrants further investigation. Despite some promising early findings, there is currently insufficient evidence to recommend increased dietary nitrate intake for the purpose of improving brain health. However, longer-term, larger-scale trials in potentially responsive groups are warranted to provide definitive evidence in this area.

Dietary Inorganic Nitrate as an Ergogenic Aid: An Expert Consensus Derived via the Modified Delphi Technique

IntroductionDietary inorganic nitrate is a popular nutritional supplement, which increases nitric oxide bioavailability and may improve exercise performance. Despite over a decade of research into the effects of dietary nitrate supplementation during exercise there is currently no expert consensus on how, when and for whom this compound could be recommended as an ergogenic aid. Moreover, there is no consensus on the safe administration of dietary nitrate as an ergogenic aid. This study aimed to address these research gaps.MethodsThe modified Delphi technique was used to establish the views of 12 expert panel members on the use of dietary nitrate as an ergogenic aid. Over three iterative rounds (two via questionnaire and one via videoconferencing), the expert panel members voted on 222 statements relating to dietary nitrate as an ergogenic aid. Consensus was reached when > 80% of the panel provided the same answer (i.e. yes or no). Statements for which > 80% of the panel cast a vote of insufficient evidence were categorised as such and removed from further voting. These statements were subsequently used to identify directions for future research.ResultsThe 12 panel members contributed to voting in all three rounds. A total of 39 statements (17.6%) reached consensus across the three rounds (20 yes, 19 no). In round one, 21 statements reached consensus (11 yes, 10 no). In round two, seven further statements reached consensus (4 yes, 3 no). In round three, an additional 11 statements reached consensus (5 yes, 6 no). The panel agreed that there was insufficient evidence for 134 (60.4%) of the statements, and were unable to agree on the outcome of the remaining statements.ConclusionsThis study provides information on the current expert consensus on dietary nitrate, which may be of value to athletes, coaches, practitioners and researchers. The effects of dietary nitrate appear to be diminished in individuals with a higher aerobic fitness (peak oxygen consumption [V̇O2peak] > 60 ml/kg/min), and therefore, aerobic fitness should be taken into account when considering use of dietary nitrate as an ergogenic aid. It is recommended that athletes looking to benefit from dietary nitrate supplementation should consume 8–16 mmol nitrate acutely or 4–16 mmol/day nitrate chronically (with the final dose ingested 2–4 h pre-exercise) to maximise ergogenic effects, taking into consideration that, from a safety perspective, athletes may be best advised to increase their intake of nitrate via vegetables and vegetable juices. Acute nitrate supplementation up to ~ 16 mmol is believed to be safe, although the safety of chronic nitrate supplementation requires further investigation. The expert panel agreed that there was insufficient evidence for most of the appraised statements, highlighting the need for future research in this area.Graphical

The effects of dietary nitrate supplementation in post‐menopausal women: Does timing matter?

There is a need for low risk, non‐estrogen therapies for cardiovascular disease prevention in post‐menopausal women, a population expected to reach 1.2 billion worldwide by 2030. Consumption of beetroot juice and other nitrate‐rich products (green leafy vegetables, supplements) is a promising non‐pharmaceutical strategy for increasing circulating nitric oxide levels and improving vascular function in post‐menopausal women. Whether time since menopause (reproductive age) influences the vasoprotective effects (arterial stiffness and endothelial function) of dietary nitrate supplementation has not been established.PURPOSETo determine the vascular protective mechanisms and efficacy of a nitric oxide boosting supplement (beetroot juice) in women at two post‐ menopausal stages (early‐ vs late‐post menopause).METHODSEarly‐ (1‐6 years following their final menstrual cycle, n=5) and late‐ (n=10) postmenopausal women consumed nitrate‐rich (300 mg/70 mL) and nitrate‐depleted beet root juice acutely and for 7 days. Percent brachial artery flow‐mediated dilation (FMD) was measured at baseline, acutely (90 minutes post‐BRJ consumption), and 15‐minutes and 30‐minutes after 20‐minute upper arm ischemia‐reperfusion (IR) injury for each drink. Brachial‐ankle pulse wave velocity (baPWV) was measured pre‐ and post‐ 7‐day supplementation.RESULTSDue to the nature of this double‐blind trial, data presented are from the baseline (pre‐juice consumption) visit only. Significant (p&lt;0.05) group differences were observed for baseline PWV (early = 1158+115 cm/s; late = 1469+296 cm/s) and FMD at the 30‐minute post‐IR injury timepoint (early = 8.4+4.6%; late = 5.8+2.7%). No group differences were observed in FMD responses at rest (p=0.2) or 15 minutes post‐IR injury (p=0.4).CONCLUSIONThese preliminary results suggest that time since menopause negatively influences arterial stiffness and may prolong recovery from endothelial IR injury in women.

The Effects of Dietary Nitrate Supplementation on Explosive Exercise Performance: A Systematic Review.

Dietary nitrate supplementation is evidenced to induce physiological effects on skeletal muscle function in fast-twitch muscle fibers and may enhance high-intensity exercise performance. An important component of sport-specific skills is the ability to perform explosive movements; however, it is unclear if nitrate supplementation can impact explosive efforts. We examined the existing evidence to determine whether nitrate supplementation improves explosive efforts lasting ≤ 6 s. PubMed, Scopus and Directory of Open Access Journals (DOAJ) were searched for articles using the following search strategy: (nitrate OR nitrite OR beetroot) AND (supplement OR supplementation) AND (explosive OR power OR high intensity OR high-intensity OR sprint* OR “athletic performance”). Out of 810 studies, 18 were eligible according to inclusion criteria. Results showed that 4 of the 10 sprint-type studies observed improved sprint time, power output, and total work in cycling or running, whereas 4 of the 10 resistance-based exercise studies observed improvements to power and velocity of free-weight bench press as well as isokinetic knee extension and flexion at certain angular velocities. These results suggest that nitrate potentially improves explosive exercise performance, but further work is required to clarify the factors influencing the efficacy of nitrate in different exercise modalities.

Effect Of Dietary Nitrate Supplementation On Adaptations To 11-weeks Of Off-season Training In Collegiate Athletes

Effect Of Dietary Nitrate Supplementation On Adaptations To 11-weeks Of Off-season Training In Collegiate Athletes

Marching to the Beet: The effect of dietary nitrate supplementation on high altitude exercise performance and adaptation during a military trekking expedition

PurposeThe aim was to investigate the effect of dietary nitrate supplementation (in the form of beetroot juice, BRJ) for 20 days on salivary nitrite (a potential precursor of bioactive nitric oxide), exercise performance and high altitude (HA) acclimatisation in field conditions (hypobaric hypoxia). MethodsThis was a single-blinded randomised control study of 22 healthy adult participants (12 men, 10 women, mean age 28 ± 12 years) across a HA military expedition. Participants were randomised pre-ascent to receive two 70 ml dose per day of either BRJ (~12.5 mmol nitrate per day; n = 11) or non-nitrate calorie matched control (n = 11). Participants ingested supplement doses daily, beginning 3 days prior to departure and continued until the highest sleeping altitude (4800 m) reached on day 17 of the expedition. Data were collected at baseline (44 m altitude), at 2350 m (day 9), 3400 m (day 12) and 4800 m (day 17). ResultsBRJ enhanced the salivary levels of nitrite (p = 0.007). There was a significant decrease in peripheral oxygen saturation and there were increases in heart rate, diastolic blood pressure, and rating of perceived exertion with increasing altitude (p=<0.001). Harvard Step Test fitness scores significantly declined at 4800 m in the control group (p = 0.003) compared with baseline. In contrast, there was no decline in fitness scores at 4800 m compared with baseline (p = 0.26) in the BRJ group. Heart rate recovery speed following exercise at 4800 m was significantly prolonged in the control group (p=<0.01) but was unchanged in the BRJ group (p = 0.61). BRJ did not affect the burden of HA illness (p = 1.00). ConclusionsBRJ increases salivary nitrite levels and ameliorates the decline in fitness at altitude but does not affect the occurrence of HA illness.

Influence of Dietary Nitrate Supplementation on Physical Performance and Body Composition Following Offseason Training in Division I Athletes

Purpose: To determine the effects of dietary nitrate supplementation, in the form of red spinach extract (RSE), on adaptations to offseason training in collegiate athletes. Methods: Sixteen Division I male baseball athletes (20.5 ± 1.7y, 90.4 ± 0.5 kg) enrolled in this study and were randomized into a RSE (n = 8) or placebo (n = 8; PL) group. Athletes completed an 11-week resistance training program during the offseason, which consisted of 2-3 workouts per week of upper and lower-body exercises and baseball-specific training. Athletes consumed a RSE (2 g; 180 mg nitrate) or PL supplement daily for the entire offseason training program. Pre and post-training, all athletes underwent one-repetition maximum (1RM) strength testing for the bench press and completed a Wingate anaerobic cycle test (WAnT). Body composition analysis was completed via a 4-compartment model, as well as muscle thickness (MT) measurement of the rectus femoris (RF) and vastus lateralis (VL) via ultrasonography. Resting heart rate and blood pressure (BP) were also obtained. Separate repeated measures analyses of variance were used to analyze all data. Results: Significant (p ≤ 0.05) main effects for time were observed for improved bench 1RM, fat-free mass, body fat percentage, RF MT, and VL MT. No significant group x time interactions (p > 0.05) were found for any measure of performance, body composition, or cardiovascular health. However, a trend for improved peak power in the WAnT was observed (p = 0.095; η2=0.200). Conclusions: These data suggest that daily RSE supplementation had no effect on performance, body composition, or cardiovascular measures in male Division I baseball players following offseason training.

Effect of Dietary Nitrate Supplementation on Sleep in Chronic Obstructive Pulmonary Disease Patients.

PurposePoor sleep quality in chronic obstructive pulmonary disease (COPD) is a result of oxygen desaturation secondary to compromised lung function. Nitrate supplementation with dietary beetroot juice is known to elevate plasma nitrate and to increase the efficiency of oxygen utilization in non-COPD individuals; whether it is of therapeutic benefit for sleep quality in COPD has not been reported.Patients and MethodsIn a counterbalanced within-subjects design involving 15 COPD patients as subjects, the subjects consumed either beetroot juice containing nitrate (BJ; ∼6.2 mmol NO3–) or placebo (NO3– -depleted juice) immediately before a night of polysomnographic monitoring. Nitrate was measured in plasma collected immediately after waking.ResultsWhile BJ consumption had no effect on the amount of time spent in any sleep stages, wake-to-N2 transitions and direct wake-to-rapid eye movement sleep (REMS) transitions, hallmarks of disordered sleep, were less frequent on the BJ night than on the placebo night. In the last two hours of the BJ night, percent time in REMS increased and delta power during deep (N3) non-REMS decreased, relative to the placebo night. Collectively, the reduced frequency of atypical transitions and the normalization of non-REMS/REMS dynamics after BJ are indicative of an improvement of sleep quality. BJ also resulted in sustained elevation of peripheral oxygen saturation (SpO2), during episodes of wake after sleep onset. Plasma nitrate was elevated nearly tenfold on the morning after BJ relative to placebo.ConclusionBJ has a normalizing effect on disordered sleep in COPD, which may be related to improved oxygen delivery.Clinical Trial RegistrationThe activities of the Regional Committees for Medical and Health Research Ethics (REC) are founded on the Norwegian law on research ethics and medical research. This study was approved by NTNU/REK midt, Det medisinske fakultet, Postboks 8905, 7491 Trondheim (REK midt 2016/1360).

The effects of dietary nitrate supplementation on endurance exercise performance and cardiorespiratory measures in healthy adults: a systematic review and meta-analysis

BackgroundNitrate supplementation is thought to improve performance in endurance sports.ObjectiveTo meta-analyze studies evaluating the effect of nitrate supplementation on endurance sports performance among adults.Data sourcesWe searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Web of Science and CINAHL without language restrictions.MethodsWe included studies that: 1) compared nitrate supplementation with placebo; 2) enrolled adults engaging in an endurance-based activity; and 3) reported a performance measure or surrogate physiologic outcome. We evaluated risk of bias using the Cochrane Collaboration tool and pooled data with a random-effects model. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to evaluate confidence in estimates.ResultsWe included 73 studies (n = 1061). Nitrate supplementation improved power output (MD 4.6 watts, P < 0.0001), time to exhaustion (MD 25.3 s, P < 0.00001), and distance travelled (MD 163.7 m, P = 0.03). We found no significant difference on perceived exertion, time trial performance and work done. Nitrate supplementation decreased VO2 (MD − 0.04 L/min, P < 0.00001) but had no significant effect on VO2max or blood lactate levels.ConclusionThe available evidence suggests that dietary nitrate supplementation benefits performance-related outcomes for endurance sports.

The Effect of Dietary Nitrate Supplementation on Isokinetic Torque in Adults: A Systematic Review and Meta-Analysis.

Dietary nitrate (NO3−) supplementation, which can enhance performance in exercise settings involving repeated high-intensity efforts, has been linked to improved skeletal muscle contractile function. Although muscular strength is an important component of explosive movements and sport-specific skills, few studies have quantified indices of muscular strength following NO3− supplementation, particularly isokinetic assessments at different angular velocities. We performed a systematic review and meta-analysis to determine whether dietary NO3− supplementation improves peak torque, as assessed by the gold standard method of isokinetic dynamometry, and if this effect was linked to the angular velocity imposed during the assessment. Dialnet, Directory of Open Access Journals, MEDLINE, PubMed, SciELO, Scopus, and SPORTDiscus were searched for articles using the following search strategy: (nitrate OR beet*) AND (supplement* OR nutr* OR diet*) AND (isokinetic OR strength OR “resistance exercise” OR “resistance training” OR “muscular power”). The meta-analysis of data from 5 studies with 60 participants revealed an overall effect size of −0.01 for the effect of nitrate supplementation on isokinetic peak torque, whereas trivial effect sizes ranging from −0.11 to 0.16 were observed for independent velocity-specific (90°/s, 180°/s, 270°/s, and 360°/s) isokinetic peak torque. Four of the five studies indicated that dietary NO3− supplementation is not likely to influence voluntary knee extensor isokinetic torque across a variety of angular velocities. These results suggest that NO3− supplementation does not influence isokinetic peak torque, but further work is required to elucidate the potential of NO3− supplementation to influence other indices of muscular strength, given the dearth of experimental evidence on this topic.