Influence Of Nitrate Supplementation Research Articles

Influence of nitrate supplementation on motor unit activity during recovery following a sustained ischemic contraction in recreationally active young males

PurposeDietary nitrate (NO3−) supplementation enhances muscle blood flow and metabolic efficiency in hypoxia, however, its efficacy on neuromuscular function and specifically, the effect on motor unit (MU) activity is less clear. We investigated whether NO3− supplementation affected MU activity following a 3 min sustained ischemic contraction and whether this is influenced by blood flow restriction (BFR) during the recovery period.MethodIn a randomized, double-blinded, cross-over design, 14 males (mean ± SD, 25 ± 6 years) completed two trials following 5 days of supplementation with NO3−-rich (NIT) or NO3−-depleted (PLA) beetroot juice to modify plasma nitrite (NO2−) concentration (482 ± 92 vs. 198 ± 48 nmol·L−1, p < 0.001). Intramuscular electromyography was used to assess MU potential (MUP) size (duration and area) and mean firing rates (MUFR) during a 3 min submaximal (25% MVC) isometric contraction with BFR. These variables were also assessed during a 90 s recovery period with the first half completed with, and the second half completed without, BFR.ResultsThe change in MUP area and MUFR, did not differ between conditions (all p > 0.05), but NIT elicited a reduction in MUP recovery time during brief isometric contractions (p < 0.001), and during recoveries with (p = 0.002) and without (p = 0.012) BFR.ConclusionThese novel observations improve understanding of the effects of NO3− on the recovery of neuromuscular function post-exercise and might have implications for recovery of muscle contractile function.Trial registrationThe study was registered on clinicaltrials.gov with ID of NCT05993715 on August 08, 2023.

Influence of nitrate supplementation on in-vitro methane emission, milk production, ruminal fermentation, and microbial methanotrophs in dairy cows fed at two forage levels

Abstract Modifying the chemical composition of a diet can be a good strategy for reducing methane emission in the rumen. However, this strategy can have adverse effects on the ruminal microbial flora. The aim of our study was to reduce methane without disturbing ruminal function by stimulating the growth and propagation of methanotrophs. In this study, we randomly divided twenty multiparous Holstein dairy cows into 4 groups in a 2×2 factorial design with two forage levels (40% and 60%) and two nitrate supplementation levels (3.5% and zero). We examined the effect of experimental diets on cow performance, ruminal fermentation, blood metabolites and changes of ruminal microbial flora throughout the experimental period (45-day). Additionally, in vitro methane emission was evaluated. Animals fed diet with 60% forage had greater dry matter intake (DMI) and milk fat content, but lower lactose and milk urea content compared with those fed 40% forage diet. Moreover, nitrate supplementation had no significant effect on DMI and milk yield. Furthermore, the interactions showed that nitrate reduces DMI and milk fat independently of forage levels. Our findings showed that nitrate can increase ammonia concentration, pH, nitrite, and acetate while reducing the total volatile fatty acids concentration, propionate, and butyrate in the rumen. With increasing nitrate, methane emission was considerably decreased possibly due to the stimulated growth of Fibrobacteria, Proteobacteria, type II Methanotrophs, and Methanoperedense nitroreducens, especially with high forage level. Overall, nitrate supplementation could potentially increase methane oxidizing microorganisms without adversely affecting cattle performance.

Influence of Nitrate Supplementation on Endurance Cyclic Sports Performance: A Systematic Review.

Endurance can be defined as the capacity to maintain one’s velocity or power output for the longest possible time. Maintaining such activity can lead to the onset of fatigue. Dietary nitrate supplementation produces an ergogenic effect due to the improvement of mitochondrial oxygen efficiency through a reduction in the oxygen cost of exercise that increases vasodilation and blood flow to the skeletal muscle in recreationally active subjects. However, the effects of dietary nitrate supplementation on well-trained endurance athletes remain unclear; such supplementation could affect more performance areas. In the present study, a systematic review of the literature was conducted to clarify the use and effects of nitrate as a dietary supplement in endurance athletes trained in cyclic sports (repetitive movement sports). A systematic search was carried out following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines in the databases of SCOPUS, Web of Science (WOS), Medline (PubMed), and Sport Discus from 1 January 2010 to 30 November 2019. Twenty-seven studies were included in the study. The methodological quality of the articles was assessed using the McMaster Critical Review Form. Statistically significant ergogenic results were obtained in 8 (29.63%) of the 27 studies investigated, with significant results obtained for cardiorespiratory parameters and performance measures. Improvement in exercise tolerance was obtained, which could help with exhaustion over time, while the improvement in exercise economics was not as clear. Additionally, the dose necessary for this ergogenic effect seems to have a direct relationship with the physical condition of the athlete. The acute dose is around 6–12.4 mmol/day of nitrate administered 2–3 h before the activity, with the same amount given as a chronic dose over 6–15 days. Further studies are required to understand the factors that affect the potential ergogenic impacts of nitrate on athletic performance among endurance athletes.

Influence of dietary nitrate supplementation on lung function and exercise gas exchange in COPD patients

BackgroundDuring exercise as pulmonary blood flow rises, pulmonary capillary blood volume increases and gas exchange surface area expands through distention and recruitment. We have previously demonstrated that pulmonary capillary recruitment is limited in COPD patients with poorer exercise tolerance. Hypoxia and endothelial dysfunction lead to pulmonary vascular dysregulation possibly in part related to nitric oxide related pathways. PurposeTo determine if increasing dietary nitrate might influence lung surface area for gas exchange and subsequently impact exercise performance. MethodsSubjects had stable, medically treated COPD (n = 25), gave informed consent, filled out the St George Respiratory Questionnaire (SGRQ), had a baseline blood draw for Hgb, performed spirometry, and had exhaled nitric oxide (exNO) measured. Then they performed the intra-breath (IB) technique for lung diffusing capacity for carbon monoxide (DLCO) as well as pulmonary blood flow (Qc). Subsequently they completed a progressive semi-recumbent cycle ergometry test to exhaustion with measures of oxygen saturation (SpO2) and expired gases along with DLCO and Qc measured during the 1st work load only. Subjects were randomized to nitrate supplement group (beetroot juice) or placebo group (black currant juice) for 8 days and returned for repeat of the above protocol. ResultsExhaled nitric oxide levels rose >200% in the nitrate group (p < 0.05) with minimal change in placebo group. The SGRQ suggested a small fall in perceived symptom limitation in the nitrate group, but no measure of resting pulmonary function differed post nitrate supplementation. With exercise, there was no influence of nitrate supplementation on peak VO2 or other measures of respiratory gas exchange. There was a tendency for the exercise DLCO to increase slightly in the nitrate group with a trend towards a rise in the DLCO/Qc relationship (p = 0.08) but not in the placebo group. The only other significant finding was a fall in the exercise blood pressure in the nitrate group, but not placebo group (p < 0.05). ConclusionDespite evidence of a rise in exhaled nitric oxide levels with nitrate supplementation, there was minimal evidence for improvement in exercise performance or pulmonary gas exchange surface area in a stable medically treated COPD population.

Influence of nitrate supplementation on VO2 kinetics and endurance of elite cyclists

The present study examined if an elevated nitrate intake would improve VO(2) kinetics, endurance, and repeated sprint capacity in elite endurance athletes. Ten highly trained cyclists (72 ± 4 mL O(2) /kg/min, mean ± standard deviation) underwent testing for VO(2) kinetics (3 × 6 min at 298 ± 28 W), endurance (120 min preload followed by a 400-kcal time trial), and repeated sprint capacity (6 × 20 s sprints, recovery 100 s) during two 6-day periods in randomized order with a daily ingestion of either 0.5 L beetroot (BR) juice to increase nitrate levels or a 0.5 L placebo (PLA) drink with blackcurrant juice. Plasma NOx (nitrate + nitrite) levels were higher (P < 0.01) in BR (147 ± 102 and 159 ± 103 μM after 4 and 6 days of beverage intake, respectively) compared with PLA (41 ± 10 and 40 ± 7 μM). VO(2) kinetics and exercise economy were the same in BR and PLA. Time-trial performance was similar with an average completion time of 18:20 and 18:37 min:s in BR and PLA, respectively, with average power outputs of 290 ± 43 W in BR and 285 ± 44 W in PLA. Peak and mean power during repeated sprinting were similar in BR and PLA. In contrast to observations in moderately trained subjects intake of BR juice had no effect on VO(2) kinetics and performance in elite cyclists.

Interaction of nitrogen status and UVB sensitivity in a temperate phytoplankton assemblage

The influence of nitrate supplementation and ultraviolet-B (UVB; 280–320 nm) enhancement was tested on a coastal phytoplankton assemblage from eastern Canada exposed to ambient or supplemental UVB irradiance, equivalent to a local 60% ozone depletion. During a 10 d-long mesocosm experiment, 24-h surface bag incubations were repeated three times with half the bags supplemented with nitrate, phosphate and silicate while the other half received only phosphate and silicate. At beginning and the end of these 24-h surface incubations, chlorophyll fluorescence measurements were performed and the abundance of photoprotective pigments diadinoxanthin and diatoxanhtin, of the PSII reaction center D1 protein and of the large subunit of the ribulose-1,5-biphosphate carboxylase/oxygenase enzyme (RuBisCO LSU) was determined. Results showed that as long as nutrients were abundant inside the mesocosms, phytoplankton exposed to supplemental UVB at the surface were able to maintain their maximal quantum yield of PSII fluorescence. As nutrients became limiting inside the mesosocoms, however, phytoplankton showed an increased sensitivity to supplemental UVB and suffered more net photodamage to the PSII reaction centers (seen as decreases in D1 protein abundance). Supplemental UVB also resulted in low abundance of RuBisCO LSU and exacerbated photoinhibition compared to the phytoplankton exposed to surface ambient irradiance. Supplementing nitrate during this nutrient deficient period limited the inactivation of the PSII reaction centers and lowered photoinhibition. Nitrate supplementation had no clear effect on the abundance of the D1 protein but it helped the community to maintain a greater abundance of RuBisCO LSU. Overall, results from this study suggest that the sensitivity of the RuBisCO enzyme to the combined effects of supplemental UVB and nitrate limitation can influence the tolerance of PSII to UVB stress.