scholarly journals Acute Dietary Nitrate Supplementation Improves Flow Mediated Dilatation of the Superficial Femoral Artery in Healthy Older Males

Nutrients ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 954 ◽  
Author(s):  
Meegan A. Walker ◽  
Tom G. Bailey ◽  
Luke McIlvenna ◽  
Jason D. Allen ◽  
Daniel J. Green ◽  
...  
Keyword(s):  
Femoral Artery ◽  
Superficial Femoral Artery ◽  
Vascular Function ◽  
Augmentation Index ◽  
Fold Increase ◽  
Beetroot Juice ◽  
Double Blind ◽  
Dietary Nitrate ◽  
Flow Mediated Dilatation ◽  
No Bioavailability

Aging is often associated with reduced leg blood flow, increased arterial stiffness, and endothelial dysfunction, all of which are related to declining nitric oxide (NO) bioavailability. Flow mediated dilatation (FMD) and passive leg movement (PLM) hyperaemia are two techniques used to measure NO-dependent vascular function. We hypothesised that acute dietary nitrate (NO3−) supplementation would improve NO bioavailability, leg FMD, and PLM hyperaemia. Fifteen healthy older men (69 ± 4 years) attended two experiment sessions and consumed either 140 mL of concentrated beetroot juice (800 mg NO3−) or placebo (NO3−-depleted beetroot juice) in a randomised, double blind, cross-over design study. Plasma nitrite (NO2−) and NO3−, blood pressure (BP), augmentation index (AIx75), pulse wave velocity (PWV), FMD of the superficial femoral artery, and PLM hyperaemia were measured immediately before and 2.5 h after consuming NO3− and placebo. Placebo had no effect but NO3− led to an 8.6-fold increase in plasma NO2−, which was accompanied by an increase in FMD (NO3−: +1.18 ± 0.94% vs. placebo: 0.23 ± 1.13%, p = 0.002), and a reduction in AIx75 (NO3−: −8.7 ± 11.6% vs. placebo: −4.6 ± 5.5%, p = 0.027). PLM hyperaemia, BP, and PWV were unchanged during both trials. This study showed that a dose of dietary NO3− improved NO bioavailability and enhanced endothelial function as measured by femoral artery FMD. These findings provide insight into the specific central and peripheral vascular responses to dietary NO3− supplementation in older adults.

scholarly journals The Effect of Dietary Nitrate Supplementation on Physiology and Performance in Trained Cyclists

2017 ◽  
Vol 12 (5) ◽  
pp. 684-689 ◽  
Author(s):  
Joseph A. McQuillan ◽  
Deborah K. Dulson ◽  
Paul B. Laursen ◽  
Andrew E. Kilding
Keyword(s):  
Time Trial ◽  
Crossover Design ◽  
Moderate Intensity ◽  
Beetroot Juice ◽  
Double Blind ◽  
Dietary Nitrate ◽  
Performance Time ◽  
Exercise Economy ◽  
Nitrate Supplementation ◽  
And Performance

Purpose:To determine the effect of dietary nitrate (NO3 –) supplementation on physiology and performance in well-trained cyclists after 6–8 d of NO3 – supplementation.Methods:Eight competitive male cyclists (mean ± SD age 26 ± 8 y, body mass 76.7 ± 6.9 kg, VO2peak 63 ± 4 mL · kg–1 · min–1) participated in a double-blind, placebo-controlled, crossover-design study in which participants ingested 70 mL of beetroot juice containing ~4 mmol NO3 – (NIT) or a NO3 –-depleted placebo (PLA), each for 8 d. Replicating pretreatment measures, participants undertook an incremental ramp assessment to determine VO2peak and first (VT1) and second (VT2) ventilatory thresholds on d 6 (NIT6 and PLA6), moderate-intensity cycling economy on d 7 (NIT7 and PLA7), and a 4-km time trial (TT) on d 8 (NIT8 and PLA8).Results:Relative to PLA, 6 d of NIT supplementation produced unclear effects for VO2peak (mean ± 95% confidence limit: 1.8% ± 5.5%) and VT1 (3.7% ± 12.3%) and trivial effects for both VT2 (–1.0% ± 3.0%) and exercise economy on d 7 (–1.0% ± 1.6%). However, effects for TT performance time (–0.7% ± 0.9%) and power (2.4% ± 2.5%) on d 8 were likely beneficial.Conclusions:Despite mostly unclear outcomes for standard physiological determinants of performance, 8 d of NO3 – supplementation resulted in likely beneficial improvements to 4-km TT performance in well-trained male endurance cyclists.

scholarly journals Acute beetroot juice supplementation on sympathetic nerve activity: a randomized, double-blind, placebo-controlled proof-of-concept study

2017 ◽  
Vol 313 (1) ◽  
pp. H59-H65 ◽  
Author(s):  
Karambir Notay ◽  
Anthony V. Incognito ◽  
Philip J. Millar
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Sympathetic Outflow ◽  
Beetroot Juice ◽  
Proof Of Concept ◽  
Burst Frequency ◽  
Double Blind ◽  
Dietary Nitrate ◽  
Nitrate Supplementation ◽  
Central Sympathetic Outflow

Acute dietary nitrate ([Formula: see text]) supplementation reduces resting blood pressure in healthy normotensives. This response has been attributed to increased nitric oxide bioavailability and peripheral vasodilation, although nitric oxide also tonically inhibits central sympathetic outflow. We hypothesized that acute dietary [Formula: see text] supplementation using beetroot (BR) juice would reduce blood pressure and muscle sympathetic nerve activity (MSNA) at rest and during exercise. Fourteen participants (7 men and 7 women, age: 25 ± 10 yr) underwent blood pressure and MSNA measurements before and after (165–180 min) ingestion of 70ml high-[Formula: see text] (~6.4 mmol [Formula: see text]) BR or [Formula: see text]-depleted BR placebo (PL; ~0.0055 mmol [Formula: see text]) in a double-blind, randomized, crossover design. Blood pressure and MSNA were also collected during 2 min of static handgrip (30% maximal voluntary contraction). The changes in resting MSNA burst frequency (−3 ± 5 vs. 3 ± 4 bursts/min, P = 0.001) and burst incidence (−4 ± 7 vs. 4 ± 5 bursts/100 heart beats, P = 0.002) were lower after BR versus PL, whereas systolic blood pressure (−1 ± 5 vs. 2 ± 5 mmHg, P = 0.30) and diastolic blood pressure (4 ± 5 vs. 5 ± 7 mmHg, P = 0.68) as well as spontaneous arterial sympathetic baroreflex sensitivity ( P = 0.95) were not different. During static handgrip, the change in MSNA burst incidence (1 ± 8 vs. 8 ± 9 bursts/100 heart beats, P = 0.04) was lower after BR versus PL, whereas MSNA burst frequency (6 ± 6 vs. 11 ± 10 bursts/min, P = 0.11) as well as systolic blood pressure (11 ± 7 vs. 12 ± 8 mmHg, P = 0.94) and diastolic blood pressure (11 ± 4 vs. 11 ± 4 mmHg, P = 0.60) were not different. Collectively, these data provide proof of principle that acute BR supplementation can decrease central sympathetic outflow at rest and during exercise. Dietary [Formula: see text] supplementation may represent a novel intervention to target exaggerated sympathetic outflow in clinical populations. NEW & NOTEWORTHY The hemodynamic benefits of dietary nitrate supplementation have been attributed to nitric oxide-mediated peripheral vasodilation. Here, we provide proof of concept that acute dietary nitrate supplementation using beetroot juice can decrease muscle sympathetic outflow at rest and during exercise in a normotensive population. These results have applications for targeting central sympathetic overactivation in disease.

Abstract WP166: Dietary Nitrate Supplements and Ischemic Stroke Recovery: A Pilot Study

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Cheryl Bushnell ◽  
Daniel Beavers ◽  
Gary Miller ◽  
Susan Reeves ◽  
Pamela Duncan ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Placebo Group ◽  
Adverse Events ◽  
Gait Speed ◽  
Stroke Recovery ◽  
Beetroot Juice ◽  
Stroke Patients ◽  
Double Blind ◽  
Dietary Nitrate ◽  
Nitrate And Nitrite

Introduction: Dietary nitrate improves cerebral blood flow and enhances physical performance by improving exercise capacity. We designed a proof-of-concept study to show increases in plasma nitrate and nitrite levels in ischemic stroke patients treated with beetroot juice shots vs placebo juice (nitrate removed). We assessed gait speed after 30 days and safety/adverse events with both groups. Methods: In a randomized placebo-controlled double-blind design, patients with NIHSS of ≥ 2 but < 20, with fair or good sitting balance and score >0 on hip flexion on the short Fugl-Meyer, within 5 days of stroke onset were enrolled. Those treated with IV alteplase or endovascular therapy, gait speed > 0.8 cm/sec, or taking nitrate-containing medications were excluded. After consent, patients were randomized to beetroot vs placebo juice. On days 1 and 30, blood was drawn for nitrate and nitrite levels before and one hour after drinking 70 cc (3.8 mM nitrate) beetroot juice (James White Fruit Juices) or an identically-appearing placebo juice, plus vitamin C 500 mg daily for 30 days in each group. On day 30, gait speed (using the 4 m walk) was assessed. Results: Eighteen participants (6 women, 12 men, 12 white, 4 African American and 2 other race-ethnicities, median age 64.6 IQR (58.7, 70.0)) were consented, 17 completed treatment (1 terminated treatment because of nausea), 16 followed for 30 days and 13 for 90 days. Baseline characteristics were balanced with regard to admission NIHSS (median 5.0 in each group), age, sex, race, risk factors, baseline gait speed (median 0.17 m/sec in active and 0.13 m/sec in placebo), and baseline nitrate/nitrite levels. There was no difference in adverse events in the two groups. The mean treatment-specific changes in nitrate were 236 micromoles/L (95% CI 170, 302) in the active and 0 (95% CI -64, 64) in the placebo group (p<0.0001). For nitrite, active group increased by 313 nanomoles/L (37, 588) and 20 nanomoles for placebo (-211, 252); p=0.045. Gait speed increased by 0.26m/sec in the active and 0.30m/sec in placebo group. Conclusions: Beetroot juice was associated with an increase in nitrate and nitrite levels, but was not associated with a change in gait speed after 30 days. Further studies with a larger population of stroke patients may be warranted.

Dietary nitrate supplementation: effects on plasma nitrite and pulmonary O2 uptake dynamics during exercise in hypoxia and normoxia

2014 ◽  
Vol 307 (7) ◽  
pp. R920-R930 ◽  
Author(s):  
James Kelly ◽  
Anni Vanhatalo ◽  
Stephen J. Bailey ◽  
Lee J. Wylie ◽  
Christopher Tucker ◽  
...  
Keyword(s):  
Exercise Tolerance ◽  
Moderate Intensity ◽  
Beetroot Juice ◽  
Moderate Intensity Exercise ◽  
Exercise Tests ◽  
Double Blind ◽  
Dietary Nitrate ◽  
Severe Intensity ◽  
Rate Of Decline ◽  
Plasma Nitrite

We investigated the effects of dietary nitrate (NO3−) supplementation on the concentration of plasma nitrite ([NO2−]), oxygen uptake (V̇o2) kinetics, and exercise tolerance in normoxia (N) and hypoxia (H). In a double-blind, crossover study, 12 healthy subjects completed cycle exercise tests, twice in N (20.9% O2) and twice in H (13.1% O2). Subjects ingested either 140 ml/day of NO3−-rich beetroot juice (8.4 mmol NO3; BR) or NO3−-depleted beetroot juice (PL) for 3 days prior to moderate-intensity and severe-intensity exercise tests in H and N. Preexercise plasma [NO2−] was significantly elevated in H-BR and N-BR compared with H-PL ( P < 0.01) and N-PL ( P < 0.01). The rate of decline in plasma [NO2−] was greater during severe-intensity exercise in H-BR [−30 ± 22 nM/min, 95% confidence interval (CI); −44, −16] compared with H-PL (−7 ± 10 nM/min, 95% CI; −13, −1; P < 0.01) and in N-BR (−26 ± 19 nM/min, 95% CI; −38, −14) compared with N-PL (−1 ± 6 nM/min, 95% CI; −5, 2; P < 0.01). During moderate-intensity exercise, steady-state pulmonary V̇o2 was lower in H-BR (1.91 ± 0.28 l/min, 95% CI; 1.77, 2.13) compared with H-PL (2.05 ± 0.25 l/min, 95% CI; 1.93, 2.26; P = 0.02), and V̇o2 kinetics was faster in H-BR (τ: 24 ± 13 s, 95% CI; 15, 32) compared with H-PL (31 ± 11 s, 95% CI; 23, 38; P = 0.04). NO3− supplementation had no significant effect on V̇o2 kinetics during severe-intensity exercise in hypoxia, or during moderate-intensity or severe-intensity exercise in normoxia. Tolerance to severe-intensity exercise was improved by NO3− in hypoxia (H-PL: 197 ± 28; 95% CI; 173, 220 vs. H-BR: 214 ± 43 s, 95% CI; 177, 249; P = 0.04) but not normoxia. The metabolism of NO2− during exercise is altered by NO3− supplementation, exercise, and to a lesser extent, hypoxia. In hypoxia, NO3− supplementation enhances V̇o2 kinetics during moderate-intensity exercise and improves severe-intensity exercise tolerance. These findings may have important implications for individuals exercising at altitude.

Blunted Hyperemic Response to Mental Stress in Young, Non-Hispanic Black Men is not Impacted by Acute Dietary Nitrate Supplementation

2021 ◽  
Author(s):  
John D. Akins ◽  
Bryon M. Curtis ◽  
Jordan C. Patik ◽  
Guillermo Olvera ◽  
Aida Nasirian ◽  
...  
Keyword(s):  
Blood Flow ◽  
Vascular Function ◽  
Mental Stress ◽  
Forearm Blood Flow ◽  
Phase 1 ◽  
Nitrate Content ◽  
Phase 2 ◽  
Dietary Nitrate ◽  
Nitrate Supplementation ◽  
No Bioavailability

Non-Hispanic black individuals have an elevated prevalence of cardiovascular disease in large part, related to impaired vascular function, secondary to reduced nitric oxide (NO) bioavailability. Nitrate supplementation increases NO bioavailability and improves vascular function. This study tested the hypothesis that forearm blood flow responses in young, non-Hispanic, black (BL) men during mental stress are blunted relative to, non-Hispanic, white (WH) men and that acute dietary nitrate supplementation would improve this response in BL men. This study was comprised of two parts. Phase 1 investigated the blood flow responses between young, BL and WH men whereas Phase 2 investigated the effect of acute nitrate supplementation in a subset of the BL men. Eleven (9 for Phase 2) BL and 8 WH men (23 ± 3 vs. 24 ± 4 y, respectively) participated. During each visit, brachial artery blood flow was assessed during 3 min of mental stress. Phase 1 was completed in one visit, while Phase 2 was completed over two visits separated by ~1-wk. During Phase 2, data were collected before and 2-h post-consumption of a beverage high in nitrate content or nitrate depleted. In Phase 1, peak forearm blood flow (FBF, P < 0.01), total FBF (P < 0.05), and forearm vascular conductance (P < 0.001) were blunted in the BL. During Phase 2, pre-beverage responses were unaffected following beverage consumption (P > 0.05 for all). Young, BL men have blunted microvascular vasodilatory responses to acute mental stress, which may not be altered following acute nitrate supplementation.

Resistive exercise versus resistive vibration exercise to counteract vascular adaptations to bed rest

2010 ◽  
Vol 108 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Noortje T. L. van Duijnhoven ◽  
Dick H. J. Thijssen ◽  
Daniel J. Green ◽  
Dieter Felsenberg ◽  
Daniel L. Belavý ◽  
...  
Keyword(s):  
Blood Flow ◽  
Femoral Artery ◽  
Superficial Femoral Artery ◽  
Vascular Function ◽  
Bed Rest ◽  
Flow Mediated Dilation ◽  
Resistive Exercise ◽  
Vibration Exercise ◽  
Echo Doppler Ultrasound ◽  
The Impact

Bed rest results in marked vascular adaptations, and resistive vibration exercise (RVE) has been shown to be an effective countermeasure. As vibration exercise has practical and logistical limitations, the use of resistive exercise (RES) alone has the preference under specific circumstances. However, it is unknown if RES is sufficient to prevent vascular adaptations to bed rest. Therefore, the purpose of the present study was to examine the impact of RES and RVE on the vascular function and structure of the superficial femoral artery in young men exposed to 60 days of bed rest. Eighteen healthy men (age: 31 ± 8 yr) were assigned to bed rest and randomly allocated to control, RES, or RVE groups. Exercise was applied 3 times/wk for 5–7 min/session. Resting diameter, blood flow, flow-mediated dilation (FMD), and dilator capacity of the superficial femoral artery were measured using echo-Doppler ultrasound. Bed rest decreased superficial femoral artery diameter and dilator capacity ( P < 0.001), which were significantly attenuated in the RVE group ( P < 0.01 and P < 0.05, respectively) but not in the RES group ( P = 0.202 and P = 0.696, respectively). Bed rest significantly increased FMD ( P < 0.001), an effect that was abolished by RVE ( P < 0.005) but not RES ( P = 0.078). Resting and hyperemic blood flow did not change in any of the groups. Thus, RVE abolished the marked increase in FMD and decrease in baseline diameter and dilator capacity normally associated with prolonged bed rest. However, the stimulus provided by RES alone was insufficient to counteract the vascular adaptations to bed rest.

scholarly journals Acute dietary nitrate supplementation does not augment submaximal forearm exercise hyperemia in healthy young men

2015 ◽  
Vol 40 (2) ◽  
pp. 122-128 ◽  
Author(s):  
Jin-Kwang Kim ◽  
David J. Moore ◽  
David G. Maurer ◽  
Daniel B. Kim-Shapiro ◽  
Swati Basu ◽  
...  
Keyword(s):  
Blood Flow ◽  
Brachial Artery ◽  
Young Men ◽  
Evidence Base ◽  
Beetroot Juice ◽  
Double Blind ◽  
Brachial Artery Diameter ◽  
Dietary Nitrate ◽  
Nitrate Supplementation ◽  
Forearm Exercise

Despite the popularity of dietary nitrate supplementation and the growing evidence base of its potential ergogenic and vascular health benefits, there is no direct information about its effects on exercising limb blood flow in humans. We hypothesized that acute dietary nitrate supplementation from beetroot juice would augment the increases in forearm blood flow, as well as the progressive dilation of the brachial artery, during graded handgrip exercise in healthy young men. In a randomized, double-blind, placebo-controlled crossover study, 12 young (22 ± 2 years) healthy men consumed a beetroot juice (140 mL Beet-It Sport, James White Juice Company) that provided 12.9 mmol (0.8 g) of nitrate or placebo (nitrate-depleted Beet-It Sport) on 2 study visits. At 3 h postconsumption, brachial artery diameter, flow, and blood velocity were measured (Doppler ultrasound) at rest and during 6 exercise intensities. Nitrate supplementation raised plasma nitrate (19.5-fold) and nitrite (1.6-fold) concentrations, and lowered resting arterial pulse wave velocity (PWV) versus placebo (all p < 0.05), indicating absorption, conversion, and a biological effect of this supplement. The supplement-associated lowering of PWV was also negatively correlated with plasma nitrite (r = –0.72, p = 0.0127). Despite these systemic effects, nitrate supplementation had no effect on brachial artery diameter, flow, or shear rates at rest (all p ≥ 0.28) or during any exercise workload (all p ≥ 0.18). These findings suggest that acute dietary nitrate supplementation favorably modifies arterial PWV, but does not augment blood flow or brachial artery vasodilation during nonfatiguing forearm exercise in healthy young men.

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