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Bowles EF, Burleigh M, Mira A, Van Breda SGJ, Weitzberg E, Rosier BT. Nitrate: "the source makes the poison". Crit Rev Food Sci Nutr 2024:1-27. [PMID: 39213282 DOI: 10.1080/10408398.2024.2395488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Interest in the role of dietary nitrate in human health and disease has grown exponentially in recent years. However, consensus is yet to be reached as to whether consuming nitrate from various food sources is beneficial or harmful to health. Global authorities continue to recommend an acceptable daily intake (ADI) of nitrate of 3.7 mg/kg-bw/day due to concerns over its carcinogenicity. This is despite evidence showing that nitrate consumption from vegetable sources, exceeding the ADI, is associated with decreased cancer prevalence and improvements in cardiovascular, oral, metabolic and neurocognitive health. This review examines the paradox between dietary nitrate and health and disease and highlights the key role of the dietary source and food matrix in moderating this interaction. We present mechanistic and epidemiological evidence to support the notion that consuming vegetable-derived nitrate promotes a beneficial increase in nitric oxide generation and limits toxic N-nitroso compound formation seen with high intakes of nitrate added during food processing or present in contaminated water. We demonstrate the need for a more pragmatic approach to nitrate-related nutritional research and guidelines. Ultimately, we provide an overview of our knowledge in this field to facilitate the various therapeutic applications of dietary nitrate, whilst maintaining population safety.
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Affiliation(s)
- E F Bowles
- Department of Human Nutrition, School of Medicine, University of Glasgow, Glasgow, UK
| | - M Burleigh
- Sport and Physical Activity Research Institute, University of the West of Scotland, Blantyre, Scotland
| | - A Mira
- Department of Genomics and Health, FISABIO Foundation, Centre for Advanced Research in Public Health, Valencia, Spain
| | - S G J Van Breda
- Department of Toxicogenomics, GROW Research Institute for Oncology and Reproduction, Maastricht University Medical Center, Maastricht, the Netherlands
| | - E Weitzberg
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - B T Rosier
- Department of Genomics and Health, FISABIO Foundation, Centre for Advanced Research in Public Health, Valencia, Spain
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2
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Wei C, Vanhatalo A, Black MI, Blackwell JR, Rajaram R, Kadach S, Jones AM. Relationships between nitric oxide biomarkers and physiological outcomes following dietary nitrate supplementation. Nitric Oxide 2024; 148:23-33. [PMID: 38697467 DOI: 10.1016/j.niox.2024.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 03/21/2024] [Accepted: 04/30/2024] [Indexed: 05/05/2024]
Abstract
Dietary nitrate (NO3-) supplementation can increase nitric oxide (NO) bioavailability, reduce blood pressure (BP) and improve muscle contractile function in humans. Plasma nitrite concentration (plasma [NO2-]) is the most oft-used biomarker of NO bioavailability. However, it is unclear which of several NO biomarkers (NO3-, NO2-, S-nitrosothiols (RSNOs)) in plasma, whole blood (WB), red blood cells (RBC) and skeletal muscle correlate with the physiological effects of acute and chronic dietary NO3- supplementation. Using a randomized, double-blind, crossover design, 12 participants (9 males) consumed NO3--rich beetroot juice (BR) (∼12.8 mmol NO3-) and NO3--depleted placebo beetroot juice (PL) acutely and then chronically (for two weeks). Biological samples were collected, resting BP was assessed, and 10 maximal voluntary isometric contractions of the knee extensors were performed at 2.5-3.5 h following supplement ingestion on day 1 and day 14. Diastolic BP was significantly lower in BR (-2 ± 3 mmHg, P = 0.03) compared to PL following acute supplementation, while the absolute rate of torque development (RTD) was significantly greater in BR at 0-30 ms (39 ± 57 N m s-1, P = 0.03) and 0-50 ms (79 ± 99 N m s-1, P = 0.02) compared to PL following two weeks supplementation. Greater WB [RSNOs] rather than plasma [NO2-] was correlated with lower diastolic BP (r = -0.68, P = 0.02) in BR compared to PL following acute supplementation, while greater skeletal muscle [NO3-] was correlated with greater RTD at 0-30 ms (r = 0.64, P=0.03) in BR compared to PL following chronic supplementation. We conclude that [RSNOs] in blood, and [NO3-] in skeletal muscle, are relevant biomarkers of NO bioavailability which are related to the reduction of BP and the enhanced muscle contractile function following dietary NO3- ingestion in humans.
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Affiliation(s)
- Chenguang Wei
- University of Exeter Medical School, Faculty of Health and Life Sciences, University of Exeter, St Luke's campus, Exeter, EX81JS, UK
| | - Anni Vanhatalo
- University of Exeter Medical School, Faculty of Health and Life Sciences, University of Exeter, St Luke's campus, Exeter, EX81JS, UK
| | - Matthew I Black
- University of Exeter Medical School, Faculty of Health and Life Sciences, University of Exeter, St Luke's campus, Exeter, EX81JS, UK
| | - Jamie R Blackwell
- University of Exeter Medical School, Faculty of Health and Life Sciences, University of Exeter, St Luke's campus, Exeter, EX81JS, UK
| | - Raghini Rajaram
- University of Exeter Medical School, Faculty of Health and Life Sciences, University of Exeter, St Luke's campus, Exeter, EX81JS, UK
| | - Stefan Kadach
- University of Exeter Medical School, Faculty of Health and Life Sciences, University of Exeter, St Luke's campus, Exeter, EX81JS, UK
| | - Andrew M Jones
- University of Exeter Medical School, Faculty of Health and Life Sciences, University of Exeter, St Luke's campus, Exeter, EX81JS, UK.
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3
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Evangelista JF, Meirelles CM, Aguiar GS, Alves R, Matsuura C. Effects of Beetroot-Based Supplements on Muscular Endurance and Strength in Healthy Male Individuals: A Systematic Review and Meta-Analysis. JOURNAL OF THE AMERICAN NUTRITION ASSOCIATION 2024; 43:77-91. [PMID: 37167368 DOI: 10.1080/27697061.2023.2211318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 04/03/2023] [Indexed: 05/13/2023]
Abstract
The aim of this study was to systematically review the current literature and analyze the effects of beetroot-based supplements (BRS) on muscular performance. Randomized controlled trials that assessed the acute or short-term effects of BRS administration on muscular endurance and/or strength in healthy male individuals were retrieved from PubMed, EMBASE, CENTRAL, and Web of Science databases from inception to February 20th, 2023. In addition, we also searched preprint papers in medRxiv.org, bibRxiv.org; thesis and dissertations included in oatd.org; and clinical trials published in ClinicalTrials.gov. Data extraction, risk of bias, and study quality were assessed by 2 authors. Meta-analyses and subgroup analyses of standardized mean differences (SMD) were performed using a random-effects model. A total of 1486 records were identified in the databases and 2 were obtained by manual search in the reference list. Of those, 27 studies attended eligibility criteria and composed this systematic review. BRS administration resulted in a positive effect on muscular endurance (SMD: 0.31; 95% confidence interval (CI): 0.10 to 0.51; p < 0.01; n = 16 studies). There was an overall significative effect for muscular strength (SMD: 0.26; 95% CI: 0.03 to 0.48; p < 0.05; n = 18 studies), but a subgroup analysis showed that significant effects were found when strength was measured in a fatigued (SMD: 0.64; 95% CI: 0.25 to 1.03; p < 0.01), but not resting state. BRS administration have a small ergogenic effect on muscular endurance and attenuate the decline in muscular strength in a fatigued state in healthy male individuals.
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Affiliation(s)
| | | | - Gabriella Salles Aguiar
- Department of Pharmacology and Psychobiology, University of the State of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Renata Alves
- Department of Pharmacology and Psychobiology, University of the State of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Cristiane Matsuura
- Department of Pharmacology and Psychobiology, University of the State of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Zoughaib WS, Hoffman RL, Yates BA, Moorthi RN, Lim K, Coggan AR. Short-term beetroot juice supplementation improves muscle speed and power but does not reduce blood pressure or oxidative stress in 65-79 y old men and women. Nitric Oxide 2023; 138-139:34-41. [PMID: 37244392 PMCID: PMC10527284 DOI: 10.1016/j.niox.2023.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/08/2023] [Accepted: 05/24/2023] [Indexed: 05/29/2023]
Abstract
We have previously demonstrated that acute ingestion of inorganic nitrate (NO3-)-rich beetroot juice (BRJ), a source of nitric oxide (NO) via the NO3- → nitrite (NO2-) → NO pathway, can improve muscle speed and power in older individuals. It is not known, however, whether this effect is maintained or perhaps even enhanced with repeated ingestion, or if tolerance develops as with organic nitrates, e.g., nitroglycerin. Using a double-blind, placebo-controlled, crossover design, we therefore studied 16 community-dwelling older (age 71 ± 5 y) individuals after both acute and short-term (i.e., daily for 2 wk) BRJ supplementation. Blood samples were drawn and blood pressure was measured periodically during each ∼3 h experiment, with muscle function determined using isokinetic dynamometry. Acute ingestion of BRJ containing 18.2 ± 6.2 mmol of NO3- increased plasma NO3- and NO2- concentrations 23 ± 11 and 2.7 ± 2.1-fold over placebo, respectively. This was accompanied by 5 ± 11% and 7 ± 13% increases in maximal knee extensor speed (Vmax) and power (Pmax), respectively. After daily supplementation for 2 wk, BRJ ingestion elevated NO3- and NO2- levels 24 ± 12 and 3.3 ± 4.0-fold, respectively, whereas Vmax and Pmax were 7 ± 9% and 9 ± 11% higher than baseline. No changes were observed in blood pressure or in plasma markers of oxidative stress with either acute or short-term NO3- supplementation. We conclude that both acute and short-term dietary NO3- supplementation result in similar improvements in muscle function in older individuals. The magnitudes of these improvements are sufficient to offset the decline resulting from a decade or more of aging and are therefore likely to be clinically significant.
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Affiliation(s)
- William S Zoughaib
- Department of Kinesiology, School of Health & Human Sciences, Indiana University Purdue University, Indianapolis, USA
| | - Richard L Hoffman
- Department of Kinesiology, School of Health & Human Sciences, Indiana University Purdue University, Indianapolis, USA
| | - Brandon A Yates
- Indiana Center for Musculoskeletal Health, School of Medicine, Indiana University School of Medicine, USA
| | - Ranjani N Moorthi
- Division of Nephrology & Hypertension, School of Medicine, Indiana University School of Medicine, USA
| | - Kenneth Lim
- Division of Nephrology & Hypertension, School of Medicine, Indiana University School of Medicine, USA
| | - Andrew R Coggan
- Department of Kinesiology, School of Health & Human Sciences, Indiana University Purdue University, Indianapolis, USA; Indiana Center for Musculoskeletal Health, School of Medicine, Indiana University School of Medicine, USA.
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Tan R, Baranauskas MN, Karl ST, Ortiz de Zevallos J, Shei RJ, Paris HL, Wiggins CC, Bailey SJ. Effects of dietary nitrate supplementation on muscular power output: Influence of supplementation strategy and population. Nitric Oxide 2023:S1089-8603(23)00047-2. [PMID: 37244391 DOI: 10.1016/j.niox.2023.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 05/18/2023] [Indexed: 05/29/2023]
Abstract
Increasing evidence indicates that dietary nitrate supplementation has the potential to increase muscular power output during skeletal muscle contractions. However, there is still a paucity of data characterizing the impact of different nitrate dosing regimens on nitric oxide bioavailability its potential ergogenic effects across various population groups. This narrative review discusses the potential influence of different dietary nitrate supplementation strategies on nitric oxide bioavailability and muscular power output in healthy adults, athletes, older adults and some clinical populations. Areas for further research are also recommended including a focus individualized nitrate dosing regimens to optimize nitric oxide bioavailability and to promote muscular power enhancements in different populations.
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Affiliation(s)
- Rachel Tan
- Department of Sports Medicine, Pepperdine University, Malibu, CA, 90263, USA.
| | - Marissa N Baranauskas
- Department of Human Physiology & Nutrition, University of Colorado, Colorado Springs, CO, 80918, USA
| | - Sean T Karl
- Department of Sports Medicine, Pepperdine University, Malibu, CA, 90263, USA
| | | | - Ren-Jay Shei
- Indiana University Alumni Association, Indiana University, Bloomington, IN, 47408, USA
| | - Hunter L Paris
- Department of Sports Medicine, Pepperdine University, Malibu, CA, 90263, USA
| | - Chad C Wiggins
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Stephen J Bailey
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, LE11 3TU, UK
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Dietary nitrate supplementation increases nitrate and nitrite concentrations in human skin interstitial fluid. Nitric Oxide 2023; 134-135:10-16. [PMID: 36889537 DOI: 10.1016/j.niox.2023.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/17/2023] [Accepted: 02/27/2023] [Indexed: 03/08/2023]
Abstract
Acute dietary nitrate (NO3-) supplementation can increase [NO3-], but not nitrite ([NO2-]), in human skeletal muscle, though its effect on [NO3-] and [NO2-] in skin remains unknown. In an independent group design, 11 young adults ingested 140 mL of NO3--rich beetroot juice (BR; 9.6 mmol NO3-), and 6 young adults ingested 140 mL of a NO3--depleted placebo (PL). Skin dialysate, acquired through intradermal microdialysis, and venous blood samples were collected at baseline and every hour post-ingestion up to 4 h to assess dialysate and plasma [NO3-] and [NO2-]. The relative recovery rate of NO3- and NO2- through the microdialysis probe (73.1% and 62.8%), determined in a separate experiment, was used to estimate skin interstitial [NO3-] and [NO2-]. Baseline [NO3-] was lower, whereas baseline [NO2-] was higher in the skin interstitial fluid relative to plasma (both P < 0.001). Acute BR ingestion increased [NO3-] and [NO2-] in the skin interstitial fluid and plasma (all P < 0.001), with the magnitude being smaller in the skin interstitial fluid (e.g., 183 ± 54 vs. 491 ± 62 μM for Δ[NO3-] from baseline and 155 ± 190 vs. 217 ± 204 nM for Δ[NO2-] from baseline at 3 h post BR ingestion, both P ≤ 0.037). However, due to the aforementioned baseline differences, skin interstitial fluid [NO2-] post BR ingestion was higher, whereas [NO3-] was lower relative to plasma (all P < 0.001). These findings extend our understanding of NO3- and NO2- distribution at rest and indicate that acute BR supplementation increases [NO3-] and [NO2-] in human skin interstitial fluid.
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Kadach S, Park JW, Stoyanov Z, Black MI, Vanhatalo A, Burnley M, Walter PJ, Cai H, Schechter AN, Piknova B, Jones AM. 15 N-labeled dietary nitrate supplementation increases human skeletal muscle nitrate concentration and improves muscle torque production. Acta Physiol (Oxf) 2023; 237:e13924. [PMID: 36606507 DOI: 10.1111/apha.13924] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/24/2022] [Accepted: 01/02/2023] [Indexed: 01/07/2023]
Abstract
AIM Dietary nitrate (NO3 - ) supplementation increases nitric oxide bioavailability and can enhance exercise performance. We investigated the distribution and metabolic fate of ingested NO3 - at rest and during exercise with a focus on skeletal muscle. METHODS In a randomized, crossover study, 10 healthy volunteers consumed 12.8 mmol 15 N-labeled potassium nitrate (K15 NO3 ; NIT) or potassium chloride placebo (PLA). Muscle biopsies were taken at baseline, at 1- and 3-h post-supplement ingestion, and immediately following the completion of 60 maximal intermittent contractions of the knee extensors. Muscle, plasma, saliva, and urine samples were analyzed using chemiluminescence to determine absolute [NO3 - ] and [NO2 - ], and by mass spectrometry to determine the proportion of NO3 - and NO2 - that was 15 N-labeled. RESULTS Neither muscle [NO3 - ] nor [NO2 - ] were altered by PLA. Following NIT, muscle [NO3 - ] (but not [NO2 - ]) was elevated at 1-h (from ~35 to 147 nmol/g, p < 0.001) and 3-h, with almost all of the increase being 15 N-labeled. There was a significant reduction in 15 N-labeled muscle [NO3 - ] from pre- to post-exercise. Relative to PLA, mean muscle torque production was ~7% greater during the first 18 contractions following NIT. This improvement in torque was correlated with the pre-exercise 15 N-labeled muscle [NO3 - ] and the magnitude of decline in 15 N-labeled muscle [NO3 - ] during exercise (r = 0.66 and r = 0.62, respectively; p < 0.01). CONCLUSION This study shows, for the first time, that skeletal muscle rapidly takes up dietary NO3 - , the elevated muscle [NO3 - ] following NO3 - ingestion declines during exercise, and muscle NO3 - dynamics are associated with enhanced torque production during maximal intermittent muscle contractions.
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Affiliation(s)
- Stefan Kadach
- Faculty of Health and Life Sciences, University of Exeter Medical School, Exeter, UK
| | - Ji Won Park
- Molecular Medicine Branch, NIDDK, National Institutes of Health, Bethesda, Maryland, USA
| | - Zdravko Stoyanov
- Faculty of Health and Life Sciences, University of Exeter Medical School, Exeter, UK
| | - Matthew I Black
- Faculty of Health and Life Sciences, University of Exeter Medical School, Exeter, UK
| | - Anni Vanhatalo
- Faculty of Health and Life Sciences, University of Exeter Medical School, Exeter, UK
| | - Mark Burnley
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Peter J Walter
- Clinical Mass Spectrometry Core, NIDDK, National Institutes of Health, Bethesda, Maryland, USA
| | - Hongyi Cai
- Clinical Mass Spectrometry Core, NIDDK, National Institutes of Health, Bethesda, Maryland, USA
| | - Alan N Schechter
- Molecular Medicine Branch, NIDDK, National Institutes of Health, Bethesda, Maryland, USA
| | - Barbora Piknova
- Molecular Medicine Branch, NIDDK, National Institutes of Health, Bethesda, Maryland, USA
| | - Andrew M Jones
- Faculty of Health and Life Sciences, University of Exeter Medical School, Exeter, UK
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Piknova B, Woessner MN, de Zevallos JO, Kraus WE, VanBruggen MD, Schechter AN, Allen JD. Human skeletal muscle nitrate and nitrite in individuals with peripheral arterial disease: Effect of inorganic nitrate supplementation and exercise. Physiol Rep 2022; 10:e15531. [PMID: 36461652 PMCID: PMC9718944 DOI: 10.14814/phy2.15531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/28/2022] [Accepted: 11/11/2022] [Indexed: 05/15/2023] Open
Abstract
Skeletal muscle may act as a reservoir for N-oxides following inorganic nitrate supplementation. This idea is most intriguing in individuals with peripheral artery disease (PAD) who are unable to endogenously upregulate nitric oxide. This study analyzed plasma and skeletal muscle nitrate and nitrite concentrations along with exercise performance, prior to and following 12-weeks of exercise training combined with oral inorganic nitrate supplementation (EX+BR) or placebo (EX+PL) in participants with PAD. Non-supplemented, at baseline, there were no differences in plasma and muscle nitrate. For nitrite, muscle concentration was higher than plasma (+0.10 nmol.g-1 ). After 12 -weeks, acute oral nitrate increased both plasma and muscle nitrate (455.04 and 121.14 nmol.g-1 , p < 0.01), which were correlated (r = 0.63, p < 0.01), plasma nitrate increase was greater than in muscle (p < 0.01). Nitrite increased in the plasma (1.01 nmol.g-1 , p < 0.05) but not in the muscle (0.22 nmol.g-1 ) (p < 0.05 between compartments). Peak walk time (PWT) increased in both groups (PL + 257.6 s;BR + 315.0 s). Six-minute walk (6 MW) distance increased only in the (EX+BR) group (BR + 75.4 m). We report no substantial gradient of nitrate (or nitrite) from skeletal muscle to plasma, suggesting a lack of reservoir-like function in participants with PAD. Oral nitrate supplementation produced increases in skeletal muscle nitrate, but not skeletal muscle nitrite. The related changes in nitrate concentration between plasma and muscle suggests a potential for inter-compartmental nitrate "communication". Skeletal muscle did not appear to play a role in within compartment nitrate reduction. Muscle nitrate and nitrite concentrations did not appear to contribute to exercise performance in patients with PAD.
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Affiliation(s)
- Barbora Piknova
- Molecular Medicine Branch, NIDDKNational Institutes of HealthBethesdaMarylandUSA
| | - Mary N. Woessner
- Institute for Health and Sport (IHES)Victoria UniversityMelbourneAustralia
| | - Joaquin Ortiz de Zevallos
- Department of Kinesiology, School of Health and Human DevelopmentUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - William E. Kraus
- Duke Molecular Physiology Institute, Duke University School of MedicineDurhamNorth CarolinaUSA
| | - Mitch D. VanBruggen
- Duke Molecular Physiology Institute, Duke University School of MedicineDurhamNorth CarolinaUSA
| | - Alan N. Schechter
- Molecular Medicine Branch, NIDDKNational Institutes of HealthBethesdaMarylandUSA
| | - Jason D. Allen
- Department of Kinesiology, School of Health and Human DevelopmentUniversity of VirginiaCharlottesvilleVirginiaUSA
- Division of Cardiovascular Medicine, School of MedicineUniversity of VirginiaCharlottesvilleVirginiaUSA
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9
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Skeletal muscle as a reservoir for nitrate and nitrite: The role of xanthine oxidase reductase (XOR). Nitric Oxide 2022; 129:102-109. [DOI: 10.1016/j.niox.2022.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 09/16/2022] [Accepted: 10/20/2022] [Indexed: 11/06/2022]
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Tan R, Pennell A, Price KM, Karl ST, Seekamp-Hicks NG, Paniagua KK, Weiderman GD, Powell JP, Sharabidze LK, Lincoln IG, Kim JM, Espinoza MF, Hammer MA, Goulding RP, Bailey SJ. Effects of Dietary Nitrate Supplementation on Performance and Muscle Oxygenation during Resistance Exercise in Men. Nutrients 2022; 14:nu14183703. [PMID: 36145080 PMCID: PMC9504620 DOI: 10.3390/nu14183703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/31/2022] [Accepted: 09/05/2022] [Indexed: 11/16/2022] Open
Abstract
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.
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Affiliation(s)
- Rachel Tan
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
- Correspondence: ; Tel.: +1-3105067041
| | - Adam Pennell
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | - Katherine M. Price
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | - Sean T. Karl
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | | | | | - Grant D. Weiderman
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | - Joanna P. Powell
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | - Luka K. Sharabidze
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | | | - Justin M. Kim
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | | | - Maya A. Hammer
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | - Richie P. Goulding
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, 1081 HZ Amsterdam, The Netherlands
| | - Stephen J. Bailey
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough LE11 3TU, UK
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11
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Enhancement of Nitric Oxide Bioavailability by Modulation of Cutaneous Nitric Oxide Stores. Biomedicines 2022; 10:biomedicines10092124. [PMID: 36140225 PMCID: PMC9496039 DOI: 10.3390/biomedicines10092124] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/22/2022] [Accepted: 08/26/2022] [Indexed: 11/17/2022] Open
Abstract
The generation of nitric oxide (NO) in the skin plays a critical role in wound healing and the response to several stimuli, such as UV exposure, heat, infection, and inflammation. Furthermore, in the human body, NO is involved in vascular homeostasis and the regulation of blood pressure. Physiologically, a family of enzymes termed nitric oxide synthases (NOS) generates NO. In addition, there are many methods of non-enzymatic/NOS-independent NO generation, e.g., the reduction of NO derivates (NODs) such as nitrite, nitrate, and nitrosylated proteins under certain conditions. The skin is the largest and heaviest human organ and contains a comparatively high concentration of these NODs; therefore, it represents a promising target for many therapeutic strategies for NO-dependent pathological conditions. In this review, we give an overview of how the cutaneous NOD stores can be targeted and modulated, leading to a further accumulation of NO-related compounds and/or the local and systemic release of bioactive NO, and eventually, NO-related physiological effects with a potential therapeutical use for diseases such as hypertension, disturbed microcirculation, impaired wound healing, and skin infections.
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12
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Silva KVC, Costa BD, Gomes AC, Saunders B, Mota JF. Factors that Moderate the Effect of Nitrate Ingestion on Exercise Performance in Adults: A Systematic Review with Meta-Analyses and Meta-Regressions. Adv Nutr 2022; 13:1866-1881. [PMID: 35580578 PMCID: PMC9526841 DOI: 10.1093/advances/nmac054] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 11/16/2021] [Accepted: 05/09/2022] [Indexed: 01/28/2023] Open
Abstract
To identify how variables such as exercise condition, supplementation strategy, participant characteristics and demographics, and practices that control oral microbiota diversity could modify the effect of inorganic nitrate ingestion (as nitrate salt supplements, beetroot juice, and nitrate-rich vegetables) on exercise performance, we conducted a systematic review with meta-analysis. Studies were identified in PubMed, Embase, and Cochrane databases. Eligibility criteria included randomized controlled trials assessing the effect of inorganic nitrate on exercise performance in healthy adults. To assess the variation in effect size, we used meta-regression models for continuous variables and subgroup analysis for categorical variables. A total of 123 studies were included in this meta-analysis, comprising 1705 participants. Nitrate was effective for improving exercise performance (standardized mean difference [SMD]: 0.101; 95% CI: 0.051, 0.151, P <0.001, I2 = 0%), although nitrate salts supplementation was not as effective (P = 0.629) as ingestion via beetroot juice (P <0.001) or a high-nitrate diet (P = 0.005). Practices that control oral microbiota diversity influenced the nitrate effect, with practices harmful to oral bacteria decreasing the ergogenic effect of nitrate. The ingestion of nitrate was most effective for exercise lasting between 2 and 10 min (P <0.001). An inverse dose-response relation between the fraction of inspired oxygen and the effect size (coefficient: -0.045, 95% CI: -0.085, -0.005, P = 0.028) suggests that nitrate was more effective in increasingly hypoxic conditions. There was a dose-response relation for acute administration (P = 0.049). The most effective acute dose was between 5 and 14.9 mmol provided ≥150 min prior to exercise (P <0.001). An inverse dose-response for protocols ≥2 d was observed (P = 0.025), with the optimal dose between 5 and 9.9 mmol·d-1 (P <0.001). Nitrate, via beetroot juice or a high-nitrate diet, improved exercise performance, in particular, in sessions lasting between 2 and 10 min. Ingestion of 5-14.9 mmol⋅d-1 taken ≥150 min prior to exercise appears optimal for performance gains and athletes should be aware that practices controlling oral microbiota diversity may decrease the effect of nitrate.
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Affiliation(s)
| | - Breno Duarte Costa
- Applied Physiology and Nutrition Research Group, Rheumatology Division, Faculty of Medicine, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Aline Corado Gomes
- Faculty of Nutrition, Federal University of Goiás (UFG), Goiania, Goiás, Brazil
| | - Bryan Saunders
- Applied Physiology and Nutrition Research Group, Rheumatology Division, Faculty of Medicine, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
- Institute of Orthopaedics and Traumatology, Faculty of Medicine FMUSP, University of São Paulo, São Paulo, Brazil
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Kadach S, Piknova B, Black MI, Park JW, Wylie LJ, Stoyanov Z, Thomas SM, McMahon NF, Vanhatalo A, Schechter AN, Jones AM. Time course of human skeletal muscle nitrate and nitrite concentration changes following dietary nitrate ingestion. Nitric Oxide 2022; 121:1-10. [PMID: 35032643 PMCID: PMC8860874 DOI: 10.1016/j.niox.2022.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/08/2022] [Accepted: 01/10/2022] [Indexed: 12/11/2022]
Abstract
Dietary nitrate (NO3−) ingestion can be beneficial for health and exercise performance. Recently, based on animal and limited human studies, a skeletal muscle NO3− reservoir has been suggested to be important in whole body nitric oxide (NO) homeostasis. The purpose of this study was to determine the time course of changes in human skeletal muscle NO3− concentration ([NO3− ) following the ingestion of dietary NO3−. Sixteen participants were allocated to either an experimental group (NIT: n = 11) which consumed a bolus of ~1300 mg (12.8 mmol) potassium nitrate (KNO3), or a placebo group (PLA: n = 5) which consumed a bolus of potassium chloride (KCl). Biological samples (muscle (vastus lateralis), blood, saliva and urine) were collected shortly before NIT or PLA ingestion and at intervals over the course of the subsequent 24 h. At baseline, no differences were observed for muscle [NO3−] and [NO2−] between NIT and PLA (P > 0.05). In PLA, there were no changes in muscle [NO3−] or [NO2−] over time. In NIT, muscle [NO3−] was significantly elevated above baseline (54 ± 29 nmol/g) at 0.5 h, reached a peak at 3 h (181 ± 128 nmol/g), and was not different to baseline from 9 h onwards (P > 0.05). Muscle [NO2−] did not change significantly over time. Following ingestion of a bolus of dietary NO3− skeletal muscle [NO3−] increases rapidly, reaches a peak at ~3 h and subsequently declines towards baseline values. Following dietary NO3− ingestion, human m. vastus lateralis [NO3−] expressed a slightly delayed pharmacokinetic profile compared to plasma [NO3−].
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Affiliation(s)
- Stefan Kadach
- University of Exeter, College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, EX1 2LU, UK
| | - Barbora Piknova
- Molecular Medicine Branch, NIDDK, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Matthew I Black
- University of Exeter, College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, EX1 2LU, UK
| | - Ji Won Park
- Molecular Medicine Branch, NIDDK, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Lee J Wylie
- University of Exeter, College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, EX1 2LU, UK
| | - Zdravko Stoyanov
- University of Exeter, College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, EX1 2LU, UK
| | - Samantha M Thomas
- Molecular Medicine Branch, NIDDK, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Nicholas F McMahon
- University of Queensland, School of Human Movement and Nutrition Sciences, University of Queensland, St Lucia, QLD, 4072, Australia
| | - Anni Vanhatalo
- University of Exeter, College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, EX1 2LU, UK
| | - Alan N Schechter
- Molecular Medicine Branch, NIDDK, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Andrew M Jones
- University of Exeter, College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, EX1 2LU, UK.
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14
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Oxygen flux from capillary to mitochondria: integration of contemporary discoveries. Eur J Appl Physiol 2022; 122:7-28. [PMID: 34940908 PMCID: PMC8890444 DOI: 10.1007/s00421-021-04854-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 11/18/2021] [Indexed: 01/03/2023]
Abstract
Resting humans transport ~ 100 quintillion (1018) oxygen (O2) molecules every second to tissues for consumption. The final, short distance (< 50 µm) from capillary to the most distant mitochondria, in skeletal muscle where exercising O2 demands may increase 100-fold, challenges our understanding of O2 transport. To power cellular energetics O2 reaches its muscle mitochondrial target by dissociating from hemoglobin, crossing the red cell membrane, plasma, endothelial surface layer, endothelial cell, interstitial space, myocyte sarcolemma and a variable expanse of cytoplasm before traversing the mitochondrial outer/inner membranes and reacting with reduced cytochrome c and protons. This past century our understanding of O2's passage across the body's final O2 frontier has been completely revised. This review considers the latest structural and functional data, challenging the following entrenched notions: (1) That O2 moves freely across blood cell membranes. (2) The Krogh-Erlang model whereby O2 pressure decreases systematically from capillary to mitochondria. (3) Whether intramyocyte diffusion distances matter. (4) That mitochondria are separate organelles rather than coordinated and highly plastic syncytia. (5) The roles of free versus myoglobin-facilitated O2 diffusion. (6) That myocytes develop anoxic loci. These questions, and the intriguing notions that (1) cellular membranes, including interconnected mitochondrial membranes, act as low resistance conduits for O2, lipids and H+-electrochemical transport and (2) that myoglobin oxy/deoxygenation state controls mitochondrial oxidative function via nitric oxide, challenge established tenets of muscle metabolic control. These elements redefine muscle O2 transport models essential for the development of effective therapeutic countermeasures to pathological decrements in O2 supply and physical performance.
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15
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Piknova B, Schechter AN, Park JW, Vanhatalo A, Jones AM. Skeletal Muscle Nitrate as a Regulator of Systemic Nitric Oxide Homeostasis. Exerc Sport Sci Rev 2021; 50:2-13. [PMID: 34669624 DOI: 10.1249/jes.0000000000000272] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ABSTRACT Non-enzymatic nitric oxide (NO) generation via the reduction of nitrate and nitrite ions, along with remarkably high levels of nitrate ions in skeletal muscle, have been recently described. Skeletal muscle nitrate storage may be critical for maintenance of NO homeostasis in healthy ageing and nitrate supplementation may be useful for treatment of specific pathophysiologies as well as enhancing normal functions.
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Affiliation(s)
- Barbora Piknova
- Molecular Medicine Branch, NIDDK, National Institutes of Health,Bethesda, MD 20892, U.S. Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
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16
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Arazi H, Eghbali E. Possible Effects of Beetroot Supplementation on Physical Performance Through Metabolic, Neuroendocrine, and Antioxidant Mechanisms: A Narrative Review of the Literature. Front Nutr 2021; 8:660150. [PMID: 34055855 PMCID: PMC8155490 DOI: 10.3389/fnut.2021.660150] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/16/2021] [Indexed: 12/20/2022] Open
Abstract
Athletes often seek to use dietary supplements to increase performance during exercise. Among various supplements, much attention has been paid to beetroot in recent years. Beetroot is a source of carbohydrates, fiber, protein, minerals, and vitamins; also, it is a natural source of nitrate and associated with improved sports performance. Nitrates can the modification of skeletal muscle contractile proteins or calcium handling after translation. The time to reach the peak plasma nitrate is between 1 and 3 h after consumption of a single dose of nitrate. Nitrate is metabolized by conversion to nitrite and subsequently nitric oxide. Beetroot can have various effects on athletic performance through nitric oxide. Nitric oxide is an intracellular and extracellular messenger for regulating certain cellular functions and causes vasodilation of blood vessels and increases blood flow. Nitric oxide seems to be effective in improving athletic performance by increasing oxygen, glucose, and other nutrients for better muscle fueling. Nitric oxide plays the main role in anabolic hormones, modulates the release of several neurotransmitters and the major mediators of stress involved in the acute hypothalamic-pituitary-adrenal response to exercise. Beetroot is an important source of compounds such as ascorbic acid, carotenoids, phenolic acids, flavonoids, betaline, and highly active phenolics and has high antioxidant properties. Beetroot supplement provides an important source of dietary polyphenols and due to the many health benefits. Phytochemicals of Beetroot through signaling pathways inhibit inflammatory diseases. In this study, the mechanisms responsible for these effects were examined and the research in this regard was reviewed.
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Affiliation(s)
- Hamid Arazi
- Department of Exercise Physiology, Faculty of Sport Sciences, University of Guilan, Rasht, Iran
| | - Ehsan Eghbali
- Department of Exercise Physiology, Faculty of Sport Sciences, University of Guilan, Rasht, Iran
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17
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Park JW, Thomas SM, Schechter AN, Piknova B. Control of rat muscle nitrate levels after perturbation of steady state dietary nitrate intake. Nitric Oxide 2021; 109-110:42-49. [PMID: 33713800 PMCID: PMC8020733 DOI: 10.1016/j.niox.2021.03.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/02/2021] [Accepted: 03/05/2021] [Indexed: 12/17/2022]
Abstract
The roles of nitrate and nitrite ions as nitric oxide (NO) sources in mammals, complementing NOS enzymes, have recently been the focus of much research. We previously reported that rat skeletal muscle serves as a nitrate reservoir, with the amount of stored nitrate being highly dependent on dietary nitrate availability, as well as its synthesis by NOS1 enzymes and its subsequent utilization. We showed that at conditions of increased NO need, this nitrate reservoir is used in situ to generate nitrite and NO, at least in part via the nitrate reductase activity of xanthine oxidoreductase (XOR). We now further investigate the dynamics of nitrate/nitrite fluxes in rat skeletal muscle after first increasing nitrate levels in drinking water and then returning to the original intake level. Nitrate/nitrite levels were analyzed in liver, blood and several skeletal muscle samples, and expression of proteins involved in nitrate metabolism and transport were also measured. Increased nitrate supply elevated nitrate and nitrite levels in all measured tissues. Surprisingly, after high nitrate diet termination, levels of both ions in liver and all muscle samples first declined to lower levels than the original baseline. During the course of the overall experiment there was a gradual increase of XOR expression in muscle tissue, which likely led to enhanced nitrate to nitrite reduction. We also noted differences in basal levels of nitrate in the different types of muscles. These findings suggest complex control of muscle nitrate levels, perhaps with multiple processes to preserve its intracellular levels.
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Affiliation(s)
- Ji Won Park
- Molecular Medicine Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Samantha M Thomas
- Molecular Medicine Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Alan N Schechter
- Molecular Medicine Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Barbora Piknova
- Molecular Medicine Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
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18
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Townsend JR, Hart TL, Haynes JT, Woods CA, Toy AM, Pihera BC, Aziz MA, Zimmerman GA, Jones MD, Vantrease WC, Gonzalez AM. Influence of Dietary Nitrate Supplementation on Physical Performance and Body Composition Following Offseason Training in Division I Athletes. J Diet Suppl 2021; 19:534-549. [PMID: 33754923 DOI: 10.1080/19390211.2021.1900482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
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.
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Affiliation(s)
| | - Tricia L Hart
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN
| | - James T Haynes
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN
| | - Clint A Woods
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN
| | - Ann M Toy
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN
| | - Bailey C Pihera
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN
| | - Marko A Aziz
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN
| | - Grace A Zimmerman
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN
| | - Megan D Jones
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN
| | - William C Vantrease
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN
| | - Adam M Gonzalez
- Department of Health Professions, Hofstra University, Hempstead, NY
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Jones AM, Vanhatalo A, Seals DR, Rossman MJ, Piknova B, Jonvik KL. Dietary Nitrate and Nitric Oxide Metabolism: Mouth, Circulation, Skeletal Muscle, and Exercise Performance. Med Sci Sports Exerc 2021; 53:280-294. [PMID: 32735111 DOI: 10.1249/mss.0000000000002470] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Nitric oxide (NO) is a gaseous signaling molecule that plays an important role in myriad physiological processes, including the regulation of vascular tone, neurotransmission, mitochondrial respiration, and skeletal muscle contractile function. NO may be produced via the canonical NO synthase-catalyzed oxidation of l-arginine and also by the sequential reduction of nitrate to nitrite and then NO. The body's nitrate stores can be augmented by the ingestion of nitrate-rich foods (primarily green leafy vegetables). NO bioavailability is greatly enhanced by the activity of bacteria residing in the mouth, which reduce nitrate to nitrite, thereby increasing the concentration of circulating nitrite, which can be reduced further to NO in regions of low oxygen availability. Recent investigations have focused on promoting this nitrate-nitrite-NO pathway to positively affect indices of cardiovascular health and exercise tolerance. It has been reported that dietary nitrate supplementation with beetroot juice lowers blood pressure in hypertensive patients, and sodium nitrite supplementation improves vascular endothelial function and reduces the stiffening of large elastic arteries in older humans. Nitrate supplementation has also been shown to enhance skeletal muscle function and to improve exercise performance in some circumstances. Recently, it has been established that nitrate concentration in skeletal muscle is much higher than that in blood and that muscle nitrate stores are exquisitely sensitive to dietary nitrate supplementation and deprivation. In this review, we consider the possibility that nitrate represents an essential storage form of NO and discuss the integrated function of the oral microbiome, circulation, and skeletal muscle in nitrate-nitrite-NO metabolism, as well as the practical relevance for health and performance.
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Affiliation(s)
- Andrew M Jones
- Department of Sport and Health Sciences, University of Exeter, Exeter, UNITED KINGDOM
| | - Anni Vanhatalo
- Department of Sport and Health Sciences, University of Exeter, Exeter, UNITED KINGDOM
| | - Douglas R Seals
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO
| | - Matthew J Rossman
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO
| | - Barbora Piknova
- Molecular Medicine Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
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20
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Beet on Alps: Time-course changes of plasma nitrate and nitrite concentrations during acclimatization to high-altitude. Nitric Oxide 2020; 107:66-72. [PMID: 33346127 DOI: 10.1016/j.niox.2020.12.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/03/2020] [Accepted: 12/14/2020] [Indexed: 11/21/2022]
Abstract
Nitric oxide seems to be involved in the altitude acclimatization process due to its ability to regulate pulmonary, cardiovascular and muscular responses to hypoxia. In this study, we investigated the plasma nitrate (NO3-) and nitrite (NO2-) response to hypobaric hypoxia in two groups of lowlanders exposed at different altitudes. For seven days, fourteen subjects were evaluated at Casati Hut (3269 m a.s.l. M.CEVEDALE) and eleven individuals were studied at Capanna Regina Margherita (4554 m a.s.l. M.ROSA). Before expeditions and at different time points during high-altitude sojourn, plasma NO3- and NO2- concentrations were measured by chemiluminescence. Resting peripheral arterial oxygen saturation (SpO2), heart rate (HR) and mean arterial blood pressure (MAP) were monitored during the experimental period. Possible confounding factors such as dietary NO3- intake, physical activity and altitude changes were controlled. Sea level plasma NO3- and NO2- concentrations significantly increased at altitude in both M.CEVEDALE group (+26.2 μM, p ≤ 0.0001, 95% CI [+17.6, +34.8] and +559.2 nM, p ≤ 0.0001, [+332.8, +785.6]) and M.ROSA group (+18.7 μM, p ≤ 0.0001, [+10.8, +26.5] and +463.7 nM, p ≤ 0.0001, [+314.3, +613.0]). Average peak value in NO metabolites concentration occurred earlier in M.CEVEDALE group vs M.ROSA group (NO3-, day 3 vs day 5, p = 0.007; NO2-, day 3 vs day 5, p = 0.019). In both groups, resting SpO2, HR and MAP values changed according to altitude levels. This study shows that exposure to hypobaric hypoxia affects nitric oxide metabolites, resulting in a significant increase in plasma NO3- and NO2- concentrations from sea level values. Interestingly, the higher the altitude reached, the longer the time taken to reach a peak in plasma concentrations of nitric oxide metabolites.
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Simultaneous Pharmacokinetic Analysis of Nitrate and its Reduced Metabolite, Nitrite, Following Ingestion of Inorganic Nitrate in a Mixed Patient Population. Pharm Res 2020; 37:235. [PMID: 33140122 DOI: 10.1007/s11095-020-02959-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 10/16/2020] [Indexed: 01/23/2023]
Abstract
PURPOSE The pharmacokinetic properties of plasma NO3- and its reduced metabolite, NO2-, have been separately described, but there has been no reported attempt to simultaneously model their pharmacokinetics following NO3- ingestion. This report describes development of such a model from retrospective analyses of concentrations largely obtained from primary endpoint efficacy trials. METHODS Linear and non-linear mixed effects analyses were used to statistically define concentration dependency on time, dose, as well as patient and study variables, and to integrate NO3- and NO2- concentrations from studies conducted at different times, locations, patient groups, and several studies in which sample range was limited to a few hours. Published pharmacokinetic studies for both substances were used to supplement model development. RESULTS A population pharmacokinetic model relating NO3- and NO2- concentrations was developed. The model incorporated endogenous levels of the two entities, and determined these were not influenced by exogenous NO3- delivery. Covariate analysis revealed intersubject variability in NO3- exposure was partially described by body weight differences influencing volume of distribution. The model was applied to visualize exposure versus response (muscle contraction performance) in individual patients. CONCLUSIONS Extension of the present first-generation model, to ultimately optimize NO3- dose versus pharmacological effects, is warranted.
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22
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Kumar RA, Kelley RC, Hahn D, Ferreira LF. Dietary nitrate supplementation increases diaphragm peak power in old mice. J Physiol 2020; 598:4357-4369. [PMID: 33460123 PMCID: PMC10195135 DOI: 10.1113/jp280027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 07/14/2020] [Indexed: 02/01/2023] Open
Abstract
KEY POINTS Respiratory muscle function declines with ageing, contributing to breathing complications in the elderly. Here we report greater in vitro respiratory muscle contractile function in old mice receiving supplemental NaNO3 for 14 days compared with age-matched controls. Myofibrillar protein phosphorylation, which enhances contractile function, did not change in our study - a finding inconsistent with the hypothesis that this post-translational modification is a mechanism for dietary nitrate to improve muscle contractile function. Nitrate supplementation did not change the abundance of calcium-handling proteins in the diaphragm of old mice, in contrast with findings from the limb muscles of young mice in previous studies. Our findings suggest that nitrate supplementation enhances myofibrillar protein function without affecting the phosphorylation status of key myofibrillar proteins. ABSTRACT Inspiratory muscle (diaphragm) function declines with age, contributing to ventilatory dysfunction, impaired airway clearance, and overall decreased quality of life. Diaphragm isotonic and isometric contractile properties are reduced with ageing, including maximal specific force, shortening velocity and peak power. Contractile properties of limb muscle in both humans and rodents can be improved by dietary nitrate supplementation, but effects on the diaphragm and mechanisms behind these improvements remain poorly understood. One potential explanation underlying the nitrate effects on contractile properties is increased phosphorylation of myofibrillar proteins, a downstream outcome of nitrate reduction to nitrite and nitric oxide. We hypothesized that dietary nitrate supplementation would improve diaphragm contractile properties in aged mice. To test our hypothesis, we measured the diaphragm function of old (24 months) mice allocated to 1 mm NaNO3 in drinking water for 14 days (n = 8) or untreated water (n = 6). The maximal rate of isometric force development (∼30%) and peak power (40%) increased with nitrate supplementation (P < 0.05). There were no differences in the phosphorylation status of key myofibrillar proteins and abundance of Ca2+-release proteins in nitrate vs. control animals. In general, our study demonstrates improved diaphragm contractile function with dietary nitrate supplementation and supports the use of this strategy to improve inspiratory function in ageing populations. Additionally, our findings suggest that dietary nitrate improves diaphragm contractile properties independent of changes in abundance of Ca2+-release proteins or phosphorylation of myofibrillar proteins.
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Affiliation(s)
- Ravi A Kumar
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL
| | - Rachel C Kelley
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL
| | - Dongwoo Hahn
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL
| | - Leonardo F Ferreira
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL
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Sodium nitrate co-supplementation does not exacerbate low dose metronomic doxorubicin-induced cachexia in healthy mice. Sci Rep 2020; 10:15044. [PMID: 32973229 PMCID: PMC7518269 DOI: 10.1038/s41598-020-71974-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 08/17/2020] [Indexed: 12/18/2022] Open
Abstract
The purpose of this study was to determine whether (1) sodium nitrate (SN) treatment progressed or alleviated doxorubicin (DOX)-induced cachexia and muscle wasting; and (2) if a more-clinically relevant low-dose metronomic (LDM) DOX treatment regimen compared to the high dosage bolus commonly used in animal research, was sufficient to induce cachexia in mice. Six-week old male Balb/C mice (n = 16) were treated with three intraperitoneal injections of either vehicle (0.9% NaCl; VEH) or DOX (4 mg/kg) over one week. To test the hypothesis that sodium nitrate treatment could protect against DOX-induced symptomology, a group of mice (n = 8) were treated with 1 mM NaNO3 in drinking water during DOX (4 mg/kg) treatment (DOX + SN). Body composition indices were assessed using echoMRI scanning, whilst physical and metabolic activity were assessed via indirect calorimetry, before and after the treatment regimen. Skeletal and cardiac muscles were excised to investigate histological and molecular parameters. LDM DOX treatment induced cachexia with significant impacts on both body and lean mass, and fatigue/malaise (i.e. it reduced voluntary wheel running and energy expenditure) that was associated with oxidative/nitrostative stress sufficient to induce the molecular cytotoxic stress regulator, nuclear factor erythroid-2-related factor 2 (NRF-2). SN co-treatment afforded no therapeutic potential, nor did it promote the wasting of lean tissue. Our data re-affirm a cardioprotective effect for SN against DOX-induced collagen deposition. In our mouse model, SN protected against LDM DOX-induced cardiac fibrosis but had no effect on cachexia at the conclusion of the regimen.
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Effects of Dietary Nitrates on Time Trial Performance in Athletes with Different Training Status: Systematic Review. Nutrients 2020; 12:nu12092734. [PMID: 32911636 PMCID: PMC7551808 DOI: 10.3390/nu12092734] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 09/04/2020] [Indexed: 12/14/2022] Open
Abstract
Much research has been done in sports nutrition in recent years as the demand for performance-enhancing substances increases. Higher intake of nitrates from the diet can increase the bioavailability of nitric oxide (NO) via the nitrate-nitrite-NO pathway. Nevertheless, the increased availability of NO does not always lead to improved performance in some individuals. This review aims to evaluate the relationship between the athlete's training status and the change in time trial performance after increased dietary nitrate intake. Articles indexed by Scopus and PubMed published from 2015 to 2019 were reviewed. Thirteen articles met the eligibility criteria: clinical trial studies on healthy participants with different training status (according to VO2max), conducting time trial tests after dietary nitrate supplementation. The PRISMA guidelines were followed to process the review. We found a statistically significant relationship between VO2max and ergogenicity in time trial performance using one-way ANOVA (p = 0.001) in less-trained athletes (VO2 < 55 mL/kg/min). A strong positive correlation was observed in experimental situations using a chronic supplementation protocol but not in acute protocol situations. In the context of our results and recent histological observations of muscle fibres, there might be a fibre-type specific role in nitric oxide production and, therefore, supplement of ergogenicity.
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San Juan AF, Dominguez R, Lago-Rodríguez Á, Montoya JJ, Tan R, Bailey SJ. Effects of Dietary Nitrate Supplementation on Weightlifting Exercise Performance in Healthy Adults: A Systematic Review. Nutrients 2020; 12:E2227. [PMID: 32722588 PMCID: PMC7469052 DOI: 10.3390/nu12082227] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 02/07/2023] Open
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.
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Affiliation(s)
- Alejandro F. San Juan
- Department of Health and Human Performance, Sport Biomechanics Laboratory, Facultad de Ciencias de la Actividad Física y del Deporte—INEF, Universidad Politécnica de Madrid, 28040 Madrid, Spain;
| | - Raul Dominguez
- Faculty of Health Science, Universidad Isabel I, 09003 Burgos, Spain;
| | | | - Juan José Montoya
- Faculty of Medicine, School of Medicine of Physical Education and Sport, Complutense University, 28040 Madrid, Spain;
| | - Rachel Tan
- Faculty of Sports Medicine, Natural Sciences Division, Pepperdine University, Malibu, CA 90263, USA;
| | - Stephen J. Bailey
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, LE11 3TU, UK;
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Nyakayiru J, van Loon LJC, Verdijk LB. Could intramuscular storage of dietary nitrate contribute to its ergogenic effect? A mini-review. Free Radic Biol Med 2020; 152:295-300. [PMID: 32224084 DOI: 10.1016/j.freeradbiomed.2020.03.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 03/09/2020] [Accepted: 03/24/2020] [Indexed: 11/19/2022]
Abstract
Extensive research performed over the past 10 years has resulted in dietary nitrate being considered a nutritional supplement that can improve exercise performance. However, there is still limited insight in the metabolic fate of dietary nitrate following the appearance of nitrate and nitrite in the circulation. Recent observations in humans suggest the storage of nitrate in skeletal muscle tissue. This short review discusses the possibility of nitrate being stored and utilized in human skeletal muscle tissue, and why confirming this may increase our understanding of how the nitrate-nitrite-NO pathway improves exercise performance. Further insight in skeletal muscle nitrate storage and metabolism may provide answers to current gaps in knowledge, such as the ergogenic benefit of acute vs multiday dietary nitrate supplementation, as well as the suggested muscle fiber-type specific effects on exercise performance. In this mini-review, specific questions that need further exploration are also discussed.
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Affiliation(s)
- Jean Nyakayiru
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, the Netherlands
| | - Luc J C van Loon
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, the Netherlands; Institute of Sports and Exercise Studies, HAN University of Applied Sciences, Nijmegen, the Netherlands
| | - Lex B Verdijk
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, the Netherlands.
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Gonzalez AM, Church DD, Townsend JR, Bagheri R. Emerging Nutritional Supplements for Strength and Hypertrophy: An Update of the Current Literature. Strength Cond J 2020. [DOI: 10.1519/ssc.0000000000000552] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Wickham KA, McCarthy DG, Pereira JM, Cervone DT, Verdijk LB, van Loon LJC, Power GA, Spriet LL. No effect of beetroot juice supplementation on exercise economy and performance in recreationally active females despite increased torque production. Physiol Rep 2020; 7:e13982. [PMID: 30653856 PMCID: PMC6336290 DOI: 10.14814/phy2.13982] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 12/18/2018] [Indexed: 01/06/2023] Open
Abstract
This study investigated the effects of acute and chronic beetroot juice (BRJ) supplementation on submaximal exercise oxygen uptake (VO2), time trial (TT) performance, and contractile properties of the plantar flexors in females. Study 1: Using a double blind, randomized, crossover design, 12 recreationally active females using hormonal contraceptives supplemented acutely (2.5 h) and chronically (8 days) with 280 mL BRJ/d (~26 mmoles nitrate [NO3−]) or a NO3−‐free placebo (PLA). On days 1 and 8, participants cycled for 10 min at 50% and 70% VO2peak and completed a 4 kJ/kg body mass TT. Plasma [NO3−] and nitrite ([NO2−]) increased significantly following BRJ supplementation versus PLA. There was no effect of BRJ supplementation on VO2 at 50% or 70% VO2peak, or TT performance. Study 2: 12 recreationally active females (n = 7 from Study 1) using hormonal contraceptives participated in a baseline visit and were supplemented acutely (2.5 h) and chronically (8 days) with 280 mL BRJ/d. Maximum voluntary strength (MVC) of the plantar flexors was assessed and a torque‐frequency curve performed. BRJ had no effect on MVC, voluntary activation, peak twitch torque, time to peak torque, or half relaxation time. Following both acute (46.6 ± 4.9% of 100 Hz torque) and chronic (47.2 ± 4.4%) supplementation, 10 Hz torque was significantly greater compared to baseline (32.9 ± 2.6%). In summary, BRJ may not be an effective ergogenic aid in recreationally active females as it did not reduce submaximal exercise VO2 or improve aerobic TT performance despite increasing low frequency torque production.
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Affiliation(s)
- Kate A Wickham
- Department of Human Health and Nutritional Sciences, University of Guelph, Ontario, Canada
| | - Devin G McCarthy
- Department of Human Health and Nutritional Sciences, University of Guelph, Ontario, Canada
| | - Jamie M Pereira
- Department of Human Health and Nutritional Sciences, University of Guelph, Ontario, Canada
| | - Daniel T Cervone
- Department of Human Health and Nutritional Sciences, University of Guelph, Ontario, Canada
| | - Lex B Verdijk
- Department of Human Biology, Maastricht University, Maastricht, The Netherlands
| | - Luc J C van Loon
- Department of Human Biology, Maastricht University, Maastricht, The Netherlands
| | - Geoffrey A Power
- Department of Human Health and Nutritional Sciences, University of Guelph, Ontario, Canada
| | - Lawrence L Spriet
- Department of Human Health and Nutritional Sciences, University of Guelph, Ontario, Canada
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Williams JK, Smallwood MJ, Benjamin N, D'Souza RJ, Shore AC, Winyard PG, Gilchrist M. Renal nitrate clearance in chronic kidney disease. Nitric Oxide 2020; 97:16-19. [PMID: 32007629 DOI: 10.1016/j.niox.2020.01.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/27/2020] [Accepted: 01/29/2020] [Indexed: 12/30/2022]
Abstract
BACKGROUND Nitric oxide (NO) is rapidly oxidised in humans to nitrite and nitrate, with nitrate being present in much greater abundance. These oxidation products can be recycled back into nitric oxide via a complex entero-salivary pathway, thus preserving NO activity. Approximately 65% of circulating nitrate is excreted in the urine in 48 h, with the excretory pathway of the remainder unknown. The effect of declining renal function on nitrate clearance is unknown METHODS: Forty five subjects, 21 M, 24F, median age 69 (range 27-75 years) with renal function assessed by CKD-EPI eGFR between 9 and 89 ml/min/1.73 m2 completed the study. Following a 24 h low nitrate diet a microplate spectrophotometric method was employed to measure plasma nitrate concentration and 24 h urinary nitrate excretion were measured to determine renal nitrate clearance. RESULTS There was a strong positive correlation between urinary nitrate clearance and eGFR, (Spearman R = 0.7665, p < 0.0001) with a moderate negative correlation between plasma nitrate concentration and CKD-EPI eGFR, (Spearman's R = -0.37, p = 0.012). There was a trend between fractional excretion of nitrate and CKD-EPI eGFR (ml/min/1.73 m2) Spearman's R 0.27, p = 0.07 though this did not reach statistical significance. Plasma nitrate concentration and serum creatinine concentration were positively correlated, Spearman's R = 0.39, p = 0.008. CONCLUSIONS We have observed a strong positive association between renal nitrate clearance and renal function such that plasma nitrate rises as renal function falls. Fractional excretion of nitrate appears to decline as renal function falls. As such, urinary nitrate excretion is unlikely to be a reliable marker of endogenous NO synthesis in settings where renal function is altered.
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Affiliation(s)
- J K Williams
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Road, EX2 5AX, UK
| | - M J Smallwood
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Road, EX2 5AX, UK
| | - N Benjamin
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Road, EX2 5AX, UK
| | - R J D'Souza
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Road, EX2 5AX, UK
| | - A C Shore
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Road, EX2 5AX, UK
| | - P G Winyard
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Road, EX2 5AX, UK
| | - M Gilchrist
- NIHR Exeter Clinical Research Facility, University of Exeter Medical School, Barrack Road, EX2 5AX, UK.
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30
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Srihirun S, Park JW, Teng R, Sawaengdee W, Piknova B, Schechter AN. Nitrate uptake and metabolism in human skeletal muscle cell cultures. Nitric Oxide 2020; 94:1-8. [PMID: 31604144 PMCID: PMC7341890 DOI: 10.1016/j.niox.2019.10.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 09/06/2019] [Accepted: 10/07/2019] [Indexed: 12/17/2022]
Abstract
Several studies show that dietary nitrate enhances exercise performance, presumably by increasing muscle blood flow and improving oxygen utilization. These effects are likely mediated by nitrate metabolites, including nitrite and nitric oxide (NO). However, the mechanisms of nitrate production, storage, and metabolism to nitrite and NO in skeletal muscle cells are still unclear. We hypothesized that exogenous nitrate can be taken up and metabolized to nitrite/NO inside the skeletal muscle. We found rapid uptake of exogeneous nitrate in both myoblasts and myotubes, increasing nitrite levels in myotubes, but not myoblasts. During differentiation we found increased expression of molybdenum containing proteins, such as xanthine oxidoreductase (XOR) and the mitochondrial amidoxime-reducing component (MARC); nitrate and nitrite reductases. Sialin, a known nitrate transporter, was detected in myoblasts; nitrate uptake decreased after sialin knockdown. Inhibition of chloride channel 1 (CLC1) also led to significantly decreased uptake of nitrate. Addition of exogenous nitrite, which resulted in higher intracellular nitrite levels, increased intracellular cGMP levels in myotubes. In summary, our results demonstrate for the first time the presence of the nitrate/nitrite/NO pathway in skeletal muscle cells, namely the existence of strong uptake of exogenous nitrate into cells and conversion of intracellular nitrate to nitrite and NO. Our results further support our previously formulated hypothesis about the importance of the nitrate to nitrite to NO intrinsic reduction pathways in skeletal muscles, which likely contributes to improved exercise tolerance after nitrate ingestion.
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Affiliation(s)
- Sirada Srihirun
- Department of Pharmacology, Faculty of Dentistry, Mahidol University, Bangkok, Thailand; Molecular Medicine Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institute of Health, Bethesda, MD, USA
| | - Ji Won Park
- Molecular Medicine Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institute of Health, Bethesda, MD, USA
| | - Rujia Teng
- Molecular Medicine Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institute of Health, Bethesda, MD, USA
| | - Waritta Sawaengdee
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Barbora Piknova
- Molecular Medicine Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institute of Health, Bethesda, MD, USA
| | - Alan N Schechter
- Molecular Medicine Branch, National Institute of Diabetes, Digestive and Kidney Diseases, National Institute of Health, Bethesda, MD, USA.
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31
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Wickham KA, Nyakayiru J, McCarthy DG, Cervone DT. Skeletal muscle nitrate storage - the missing piece of the nitrate supplementation puzzle? J Physiol 2019; 597:5323-5325. [PMID: 31520400 DOI: 10.1113/jp278785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 09/12/2019] [Indexed: 11/08/2022] Open
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32
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Wickham KA, Spriet LL. No longer beeting around the bush: a review of potential sex differences with dietary nitrate supplementation. Appl Physiol Nutr Metab 2019; 44:915-924. [DOI: 10.1139/apnm-2019-0063] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Over the last decade there has been substantial interest in the health and athletic performance benefits associated with acute and chronic dietary nitrate (NO3–) supplementation. Dietary NO3–, commonly found in leafy green and root vegetables, undergoes sequential reduction to nitrite and nitric oxide (NO) via the enterosalivary circulation. Importantly, NO has been shown to elicit a number of biological effects ranging from blood pressure reduction to improved exercise economy and athletic performance. However, a common absence within biological research is the lack of female participants, which is often attributed to the added complexity of hormonal fluctuations throughout the menstrual cycle. Despite mounting evidence supporting significant anthropometric, metabolic, and physiological differences between the sexes, this problem extends to the field of dietary NO3– supplementation where women are underrepresented as research participants. This review examines the existing dietary NO3– supplementation research with regards to dietary NO3– pharmacokinetics, resting blood pressure, exercise economy and performance, and mechanisms of action. It also provides evidence and rationale for potential sex differences in response to dietary NO3– supplementation and future directions for this field of research. Novelty Dietary NO3– supplementation has been shown to have positive impacts on health and athletic performance in generally male populations. However, women are underrepresented in dietary NO3– supplementation research. The present evidence suggests that sex differences exist in response to dietary NO3– supplementation and this review highlights avenues for future research.
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Affiliation(s)
- Kate A. Wickham
- Faculty of Applied Health Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Lawrence L. Spriet
- Human Health & Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
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Wylie LJ, Park JW, Vanhatalo A, Kadach S, Black MI, Stoyanov Z, Schechter AN, Jones AM, Piknova B. Human skeletal muscle nitrate store: influence of dietary nitrate supplementation and exercise. J Physiol 2019; 597:5565-5576. [PMID: 31350908 PMCID: PMC9358602 DOI: 10.1113/jp278076] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 07/22/2019] [Indexed: 12/18/2022] Open
Abstract
Rodent skeletal muscle contains a large store of nitrate that can be augmented by the consumption of dietary nitrate. This muscle nitrate reservoir has been found to be an important source of nitrite and nitric oxide (NO) via its reduction by tissue xanthine oxidoreductase. To explore if this pathway is also active in human skeletal muscle during exercise, and if it is sensitive to local nitrate availability, we assessed exercise-induced changes in muscle nitrate and nitrite concentrations in young healthy humans, under baseline conditions and following dietary nitrate consumption. We found that baseline nitrate and nitrite concentrations were far higher in muscle than in plasma (~4-fold and ~29-fold, respectively), and that the consumption of a single bolus of dietary nitrate (12.8 mmol) significantly elevated nitrate concentration in both plasma (~19-fold) and muscle (~5-fold). Consistent with these observations, and with previous suggestions of active muscle nitrate transport, we present western blot data to show significant expression of the active nitrate/nitrite transporter sialin in human skeletal muscle. Furthermore, we report an exercise-induced reduction in human muscle nitrate concentration (by ~39%), but only in the presence of an increased muscle nitrate store. Our results indicate that human skeletal muscle nitrate stores are sensitive to dietary nitrate intake and may contribute to NO generation during exercise. Together, these findings suggest that skeletal muscle plays an important role in the transport, storage and metabolism of nitrate in humans.
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Affiliation(s)
- Lee J. Wylie
- Sport and Health SciencesCollege of Life and Environmental SciencesSt Luke's CampusUniversity of Exeter Exeter EX1 2LU UK
| | - Ji Won Park
- Molecular Medicine BranchNIDDKNational Institutes of Health Bethesda MD 20892–1822 USA
| | - Anni Vanhatalo
- Sport and Health SciencesCollege of Life and Environmental SciencesSt Luke's CampusUniversity of Exeter Exeter EX1 2LU UK
| | - Stefan Kadach
- Sport and Health SciencesCollege of Life and Environmental SciencesSt Luke's CampusUniversity of Exeter Exeter EX1 2LU UK
| | - Matthew I. Black
- Sport and Health SciencesCollege of Life and Environmental SciencesSt Luke's CampusUniversity of Exeter Exeter EX1 2LU UK
| | - Zdravko Stoyanov
- Sport and Health SciencesCollege of Life and Environmental SciencesSt Luke's CampusUniversity of Exeter Exeter EX1 2LU UK
| | - Alan N. Schechter
- Molecular Medicine BranchNIDDKNational Institutes of Health Bethesda MD 20892–1822 USA
| | - Andrew M. Jones
- Sport and Health SciencesCollege of Life and Environmental SciencesSt Luke's CampusUniversity of Exeter Exeter EX1 2LU UK
| | - Barbora Piknova
- Molecular Medicine BranchNIDDKNational Institutes of Health Bethesda MD 20892–1822 USA
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Influence of Equimolar Doses of Beetroot Juice and Sodium Nitrate on Time Trial Performance in Handcycling. Nutrients 2019; 11:nu11071642. [PMID: 31323779 PMCID: PMC6683039 DOI: 10.3390/nu11071642] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/11/2019] [Accepted: 07/16/2019] [Indexed: 12/17/2022] Open
Abstract
This study aimed to investigate the influence of a single dose of either beetroot juice (BR) or sodium nitrate (NIT) on performance in a 10 km handcycling time trial (TT) in able-bodied individuals and paracyclists. In total, 14 able-bodied individuals [mean ± SD; age: 28 ± 7 years, height: 183 ± 5 cm, body mass (BM): 82 ± 9 kg, peak oxygen consumption (VO2peak): 33.9 ± 4.2 mL/min/kg] and eight paracyclists (age: 40 ± 11 years, height: 176 ± 9cm, BM: 65 ± 9 kg, VO2peak: 38.6 ± 10.5 mL/min/kg) participated in the study. All participants had to perform three TT on different days, receiving either 6 mmol nitrate as BR or NIT or water as a placebo. Time-to-complete the TT, power output (PO), as well as oxygen uptake (VO2) were measured. No significant differences in time-to-complete the TT were found between the three interventions in able-bodied individuals (p = 0.80) or in paracyclists (p = 0.61). Furthermore, VO2 was not significantly changed after the ingestion of BR or NIT in either group (p < 0.05). The PO to VO2 ratio was significantly higher in some kilometers of the TT in able-bodied individuals (p < 0.05). The ingestion of BR or NIT did not increase handcycling performance in able-bodied individuals or in paracyclists.
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Clanton TL. Managing the power grid: how myoglobin can regulate PO2 and energy distribution in skeletal muscle. J Appl Physiol (1985) 2019; 126:787-790. [DOI: 10.1152/japplphysiol.00614.2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Affiliation(s)
- Thomas L. Clanton
- Department of Applied Physiology and Kinesiology, the University of Florida Gainesville, Florida
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36
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Troutman AD, Gallardo EJ, Brown MB, Coggan AR. Measurement of nitrate and nitrite in biopsy-sized muscle samples using HPLC. J Appl Physiol (1985) 2018; 125:1475-1481. [PMID: 30113272 DOI: 10.1152/japplphysiol.00625.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Studies of rats have indicated that skeletal muscle plays a central role in whole-body nitrate ( NO3- )/nitrite ( NO2- )/nitric oxide (NO) metabolism. Extending these results to humans, however, is challenging due to the small size of needle biopsy samples. We therefore developed a method to precisely and accurately quantify NO3- and NO2- in biopsy-sized muscle samples. NO3- and NO2- were extracted from rat soleus samples using methanol combined with mechanical homogenization + ultrasound, bead beating, pulverization at liquid N2 temperature or pulverization + 0.5% Triton X-100. After centrifugation to remove proteins, NO3- and NO2- were measured using HPLC. Mechanical homogenization + ultrasound resulted in the lowest NO3- content (62 ± 20 pmol/mg), with high variability [coefficient of variation (CV) >50%] across samples from the same muscle. The NO2- / NO3- ratio (0.019 ± 0.006) was also elevated, suggestive of NO3- reduction during tissue processing. Bead beating or pulverization yielded lower NO2- and slightly higher NO3- levels, but reproducibility was still poor. Pulverization + 0.5% Triton X-100 provided the highest NO3- content (124 ± 12 pmol/mg) and lowest NO2- / NO3- ratio (0.008 ± 0.001), with the least variability between duplicate samples (CV ~15%). These values are consistent with literature data from larger rat muscle samples analyzed using chemiluminescence. Samples were stable for at least 5 wk at -80°C, provided residual xanthine oxidoreductase activity was blocked using 0.1 mmol/l oxypurinol. We have developed a method capable of measuring NO3- and NO2- in <1 mg of muscle. This method should prove highly useful in investigating the role of skeletal muscle in NO3- / NO2- /NO metabolism in human health and disease. NEW & NOTEWORTHY Measurement of nitrate and especially nitrite in small, i.e., biopsy-sized, muscle samples is analytically challenging. We have developed a precise, accurate, and convenient method for doing so using an affordable commercial HPLC system.
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Affiliation(s)
- Ashley D Troutman
- Department of Kinesiology, Indiana University-Purdue University Indianapolis , Indianapolis, Indiana.,Department of Physical Therapy, Indiana University-Purdue University Indianapolis , Indianapolis, Indiana
| | - Edgar J Gallardo
- Department of Kinesiology, Indiana University-Purdue University Indianapolis , Indianapolis, Indiana
| | - Mary Beth Brown
- Department of Physical Therapy, Indiana University-Purdue University Indianapolis , Indianapolis, Indiana
| | - Andrew R Coggan
- Department of Kinesiology, Indiana University-Purdue University Indianapolis , Indianapolis, Indiana.,Department of Cellular and Integrative Physiology, Indiana-University Purdue University Indianapolis , Indianapolis, Indiana
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37
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Wang L, Almeida LEF, Kamimura S, van der Meulen JH, Nagaraju K, Quezado M, Wakim P, Quezado ZMN. The role of nitrite in muscle function, susceptibility to contraction injury, and fatigability in sickle cell mice. Nitric Oxide 2018; 80:70-81. [PMID: 30114530 PMCID: PMC6186197 DOI: 10.1016/j.niox.2018.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 07/05/2018] [Accepted: 08/07/2018] [Indexed: 12/17/2022]
Abstract
Sickle cell disease (SCD) patients can have limited exercise capacity and muscle dysfunction characterized by decreased force, atrophy, microvascular abnormalities, fiber distribution changes, and skeletal muscle energetics abnormalities. Growing evidence suggests that in SCD there is alteration in nitric oxide (NO) availability/signaling and that nitrate/nitrite can serve as a NO reservoir and enhance muscle performance. Here, we examined effects of nitrite on muscle strength, exercise capacity, and on contractile properties of fast-(extensor digitorum longus, EDL) and slow-twitch (soleus) muscles in SCD mice. Compared to controls, homozygotes (sickling) had decreased grip strength, impaired wheel running performance, and decreased muscle mass of fast-twitch, but not slow-twitch muscle. Nitrite treatment yielded increases in nitrite plasma levels in controls, heterozygotes, and homozygotes but decreases in muscle nitrite levels in heterozygotes and homozygotes. Regardless of genotype, nitrite yielded increases in grip strength, which were coupled with increases in specific force in EDL, but not in soleus muscle. Further, nitrite increased EDL, but not soleus, fatigability in all genotypes. Conversely, in controls, nitrite decreased, whereas in homozygotes, it increased EDL susceptibility to contraction-induced injury. Interestingly, nitrite yielded no changes in distances ran on the running wheel. These differential effects of nitrite in fast- and slow-twitch muscles suggest that its ergogenic effects would be observed in high-intensity/short exercises as found with grip force increases but no changes on wheel running distances. Further, the differential effects of nitrite in homozygotes and control animals suggests that sickling mice, which have altered NO availability/signaling, handle nitrite differently than do control animals.
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Affiliation(s)
- Li Wang
- The Sheikh Zayed Institute for Pediatric Surgical Innovation and Center for Neuroscience Research, Children's Research Institute, Washington, DC, 20010, USA
| | - Luis E F Almeida
- Department of Perioperative Medicine, National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sayuri Kamimura
- Department of Perioperative Medicine, National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jack H van der Meulen
- Center for Genetic Medicine Research, Children's Research Institute, Children's National Health System, Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Washington, DC, 20010, USA
| | - Kanneboyina Nagaraju
- Center for Genetic Medicine Research, Children's Research Institute, Children's National Health System, Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Washington, DC, 20010, USA
| | - Martha Quezado
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Paul Wakim
- Biostatistics and Clinical Epidemiology Service, National Institutes of Health Clinical Center, Bethesda, MD, 20892, USA
| | - Zenaide M N Quezado
- Department of Perioperative Medicine, National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA.
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38
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Coggan AR, Peterson LR. Dietary Nitrate Enhances the Contractile Properties of Human Skeletal Muscle. Exerc Sport Sci Rev 2018; 46:254-261. [PMID: 30001275 PMCID: PMC6138552 DOI: 10.1249/jes.0000000000000167] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We review recent studies of the effects of dietary nitrate on human muscle contractile function and discuss possible underlying mechanisms. Dietary nitrate, a source of nitric oxide (NO), improves the contractile properties of human muscle. We present the hypothesis that this is due to nitrosylation of the ryanodine receptor and increased NO signaling via the soluble guanyl cyclase-cyclic guanosine monophosphate-protein kinase G pathway, which together increase the free intracellular Ca2+ concentration along with the Ca2+ sensitivity of the myofilaments themselves.
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Affiliation(s)
- Andrew R Coggan
- Departments of Kinesiology and.,Cellular and Integrative Physiology, Indiana University Purdue University Indianapolis, Indianapolis, IN
| | - Linda R Peterson
- Medicine and.,Radiology, Washington University School of Medicine, St. Louis, MO
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39
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Bender D, Townsend JR, Vantrease WC, Marshall AC, Henry RN, Heffington SH, Johnson KD. Acute beetroot juice administration improves peak isometric force production in adolescent males. Appl Physiol Nutr Metab 2018. [DOI: 10.1139/apnm-2018-0050] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The purpose of this study was to examine the effects of acute beetroot juice (BR) administration on repeated sprint performance and isometric force production in adolescent males. Twelve male adolescents (age, 16.8 ± 1.0 years; height, 178.8 ± 9.2 cm; mass, 74.8 ± 12.5 kg; peak height velocity, 2.53 ± 1.2 years) participated in this double-blind, placebo-controlled, crossover designed study. Participants consumed 2 × 70 mL of BR (∼12.9 mmol NO3−; Beet It Sport) or a nitrate-depleted placebo (PL) at 2.5 h prior to performing isometric mid-thigh pulls (IMTP) and 4 repeated 20-s Wingate sprints interspersed with 4 min of rest. Sprint data were analyzed by a 2 × 4 (group × time) repeated-measures ANOVA while a dependent t test was used to compare conditions for IMTP peak force. A significant main effect for time (p < 0.05) was observed for peak power (PP), average power (Pavg), and fatigue index (FI) across sprints. Compared with sprint 1, sprint 4 resulted in significant decreases in PP (p < 0.000; −16.6%) and Pavg (p = 0.000; −21.8%) and FI was significantly elevated (p < 0.000; 15.2%). No significant group × time interactions were observed between conditions for PP (p = 0.402), Pavg (p = 0.479), or FI (p = 0.37). IMTP peak force was significantly higher (p = 0.004; 13.9%) following BR consumption compared with PL. The repeated sprint protocol resulted in significant fatigue while BR did not influence sprint performance. However, it appears BR administration may improve peak force production in adolescent males.
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Affiliation(s)
- David Bender
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN 37204, USA
| | - Jeremy R. Townsend
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN 37204, USA
| | - William C. Vantrease
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN 37204, USA
| | - Autumn C. Marshall
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN 37204, USA
| | - Ruth N. Henry
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN 37204, USA
| | - Stephen H. Heffington
- School of Physician Assistant Studies, Lipscomb University, Nashville, TN 37204, USA
| | - Kent D. Johnson
- Exercise and Nutrition Science Graduate Program, Lipscomb University, Nashville, TN 37204, USA
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40
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Tan R, Wylie LJ, Thompson C, Blackwell JR, Bailey SJ, Vanhatalo A, Jones AM. Beetroot juice ingestion during prolonged moderate-intensity exercise attenuates progressive rise in O2 uptake. J Appl Physiol (1985) 2018; 124:1254-1263. [DOI: 10.1152/japplphysiol.01006.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Nitrate-rich beetroot juice (BR) supplementation has been shown to increase biomarkers of nitric oxide availability with implications for the physiological responses to exercise. We hypothesized that BR supplementation before and during prolonged moderate-intensity exercise would maintain an elevated plasma nitrite concentration ([[Formula: see text]]), attenuate the expected progressive increase in V̇o2 over time, and improve performance in a subsequent time trial (TT). In a double-blind, randomized, crossover design, 12 men completed 2 h of moderate-intensity cycle exercise followed by a 100-kJ TT in three conditions: 1) BR before and 1 h into exercise (BR + BR); 2) BR before and placebo (PL) 1 h into exercise (BR + PL); and 3) PL before and 1 h into exercise (PL + PL). During the 2-h moderate-intensity exercise bout, plasma [[Formula: see text]] declined by ~17% in BR + PL but increased by ~8% in BR + BR such that, at 2 h, plasma [[Formula: see text]] was greater in BR + BR than both BR + PL and PL + PL ( P < 0.05). V̇o2 was not different among conditions over the first 90 min of exercise but was lower at 120 min in BR + BR (1.73 ± 0.24 l/min) compared with BR + PL (1.80 ± 0.21 l/min; P = 0.08) and PL + PL (1.83 ± 0.27 l/min; P < 0.01). The decline in muscle glycogen concentration over the 2-h exercise bout was attenuated in BR + BR (~28% decline) compared with BR + PL (~44% decline) and PL + PL (~44% decline; n = 9, P < 0.05). TT performance was not different among conditions ( P > 0.05). BR supplementation before and during prolonged moderate-intensity exercise attenuated the progressive rise in V̇o2 over time and appeared to reduce muscle glycogen depletion but did not enhance subsequent TT performance. NEW & NOTEWORTHY We show for the first time that ingestion of nitrate during exercise preserves elevated plasma [nitrite] and negates the progressive rise in O2 uptake during prolonged moderate-intensity exercise.
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Affiliation(s)
- Rachel Tan
- Sports and Health Sciences, College of Life and Environmental Sciences, St. Luke’s Campus, University of Exeter, Exeter, United Kingdom
| | - Lee J. Wylie
- Sports and Health Sciences, College of Life and Environmental Sciences, St. Luke’s Campus, University of Exeter, Exeter, United Kingdom
| | - Christopher Thompson
- Sports and Health Sciences, College of Life and Environmental Sciences, St. Luke’s Campus, University of Exeter, Exeter, United Kingdom
| | - Jamie R. Blackwell
- Sports and Health Sciences, College of Life and Environmental Sciences, St. Luke’s Campus, University of Exeter, Exeter, United Kingdom
| | - Stephen J. Bailey
- Sports and Health Sciences, College of Life and Environmental Sciences, St. Luke’s Campus, University of Exeter, Exeter, United Kingdom
| | - Anni Vanhatalo
- Sports and Health Sciences, College of Life and Environmental Sciences, St. Luke’s Campus, University of Exeter, Exeter, United Kingdom
| | - Andrew M. Jones
- Sports and Health Sciences, College of Life and Environmental Sciences, St. Luke’s Campus, University of Exeter, Exeter, United Kingdom
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41
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Gilliard CN, Lam JK, Cassel KS, Park JW, Schechter AN, Piknova B. Effect of dietary nitrate levels on nitrate fluxes in rat skeletal muscle and liver. Nitric Oxide 2018; 75:1-7. [PMID: 29378248 DOI: 10.1016/j.niox.2018.01.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 01/17/2018] [Accepted: 01/23/2018] [Indexed: 01/28/2023]
Abstract
Rodent skeletal muscle has high levels of nitrate ions and this endogenous nitrate reservoir can supply nitrite/nitric oxide (NO) for functional hyperemia and/or for other physiological processes in muscle during exercise. Mice with a NOS1 knockout have markedly reduced muscle nitrate levels, suggesting NO production by NOS and its reaction with oxymyoglobin as a source of nitrate. However, oxygen levels are normally low in most internal organs, which raises the possibility that nitrate-derived NO pathway is physiologically important even at "normoxia", and muscle nitrate reservoir is the main endogenous NO backup when exogeneous (dietary) nitrate intake is low. Using dietary nitrate manipulations, we explore the importance of diet for maintaining and renewal of muscle nitrate reservoir and its levels in other tissues. We found that skeletal muscle nitrate is extensively used when nitrate in diet is low. One week of nitrate starvation leads to dramatic nitrate depletion in skeletal muscle and a substantial decrease in liver. Nitrate depleted from skeletal muscle during starvation is quickly recovered from new dietary sources, with an unexpected significant "overload" compared with animals not subjected to nitrate starvation. Our results suggest the importance of dietary nitrate for nitrate reserves in muscle and in other tissues, when compared with endogenous NOS-derived sources. This requires an active transport mechanism for sequestering nitrate into cells, stimulated by lack of dietary nitrate or other enzymatic changes. These results confirm the hypothesis that muscle is a major storage site for nitrate in mammals.
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Affiliation(s)
- Cameron N Gilliard
- Molecular Medicine Branch, NIDDK, NIH, Bethesda, MD, United States; Penn State Health Milton S. Hershey Medical Center, Department of Anesthesiology, Hershey, PA, United States
| | - Jeff K Lam
- Molecular Medicine Branch, NIDDK, NIH, Bethesda, MD, United States; Icahn School of Medicine, Mt. Sinai, New York, NY, United States
| | - Katelyn S Cassel
- Molecular Medicine Branch, NIDDK, NIH, Bethesda, MD, United States
| | - Ji Won Park
- Molecular Medicine Branch, NIDDK, NIH, Bethesda, MD, United States
| | - Alan N Schechter
- Molecular Medicine Branch, NIDDK, NIH, Bethesda, MD, United States
| | - Barbora Piknova
- Molecular Medicine Branch, NIDDK, NIH, Bethesda, MD, United States.
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