Primary study

Unclassified

Year 2013
Journal Journal of Science and Medicine in Sport
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Introduction: Beetroot juice is a naturally rich source of nitrate (NO3-), a compound hypothesized to enhance endurance performance by improving exercise efficiency. This study investigated the effect of multiple doses of beetroot juice on 2000m ergometer rowing performance in well trained athletes. Methods: Ten highly trained male rowers (17±3.4 h training per week) volunteered to participate in a counterbalanced, placebo controlled, cross-over study. Subjects were given either 0mmol (PLACEBO), 4.2mmol (SINGLE) or 8.4mmol (DOUBLE) NO3- via a beetroot juice supplement 2 h before undertaking a 2000mtest on a rowing ergometer. Blood samples were taken before supplement ingestion and immediately before the rowing test for later analysis of plasma [NO3-] and [nitrite (NO2-)]. Results: The SINGLE dose demonstrated a trivial effect compared to PLACEBO on 2000m time to completion. A possibly beneficial effect of DOUBLE was found compared to SINGLE (mean difference: -1.8±2.1 s) and PLACEBO (-1.6±1.6 s) respectively. Plasma [NO2-] and [NO3-] demonstrated a dose-response effect, with greater amounts of nitrate ingested leading to substantially higher concentrations (DOUBLE > SINGLE > PLACEBO). There was a moderate but insignificant positive correlation (r = 0.573, p = 0.065) between change in plasma [NO2-] and improvement in performance. Conclusion: When compared with placebo, a high (8.4mmol NO3-) but not moderate (4.2mmol NO3-) dose of beetroot juice 2 h before exercise improved 2000mrowing performance in highly trained athletes.

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Unclassified

Year 2023
Journal Current Developments in Nutrition
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Objectives: Cardiovascular disease (CVD) is the leading cause of death in women, with the risk being greater following menopause. Consumption of beetroot juice and other nitraterich foods is a promising non‐pharmacological strategy for increasing systemic nitric oxide to improve endothelial function in elderly populations. The purpose of this randomized, placebo‐controlled, crossover clinical trial was to determine if short‐term dietary nitrate supplementation, in the form of beetroot juice, could improve baseline endothelial function in postmenopausal women at two distinct stages of menopause. Methods: Early‐ (1–6 years following their final menstrual period (FMP), n=12) and late‐ (>6 years FMP, n=12) postmenopausal women consumed nitrate‐rich (300 mg/70mL) and nitrate‐depleted beetroot juice (0 mg/70 mL, placebo) for 7 days. Brachial artery flow mediated dilation (FMD)was measured pre‐ and post‐7‐day supplementation. Results: Analyses with general linear models (SPSS) revealed a significant (p<0.05) treatment*time interaction (p=0.047) for baseline FMD (FMDnitrate=4.43±2.80% and FMDplacebo=5.27±2.37%) and post‐supplementation FMD (FMDnitrate=6.47±2.52% and FMDplacebo=5.09±3.01%). Stratification of postmenopausal women into early‐ and lategroups revealed no significant interaction effect. Conclusions: These results suggest that 7 days of nitrate‐rich (300 mg/70 mL) beetroot juice supplementation is sufficient to increase resting endothelial function to a similar extent in postmenopausal women at both postmenopausal stages. Funding Sources: T32DK120509, T32GM108563, UL1 TR002014.

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Primary study

Unclassified

Year 2016
Journal American journal of physiology. Gastrointestinal and liver physiology
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Nitric oxide alters gastric blood flow, improves vascular function, and mediates glucose uptake within the intestines and skeletal muscle. Dietary nitrate, acting as a source of nitric oxide, appears to be a potential low-cost therapy that may help maintain glucose homeostasis. In a randomized, double-blind, placebo-controlled crossover study, 31 young and older adult participants had a standardized breakfast, supplemented with either nitrate-rich beetroot juice (11.91 mmol nitrate) or nitrate-depleted beetroot juice as placebo (0.01 mmol nitrate). MRI was used to assess apparent diffusion coefficient (ADC), portal vein flux, and velocity. Plasma glucose, incretin, and C-peptide concentrations and blood pressure were assessed. Outcome variables were measured at baseline and hourly for 3 h. Compared with a placebo, beetroot juice resulted in a significant elevation in plasma nitrate and plasma nitrite concentration. No differences were seen for the young or older adult cohorts between placebo and beetroot juice for ADC, or portal vein flux. There was an interaction effect in the young adults between visits for portal vein velocity. Nitrate supplementation did not reduce plasma glucose, active GLP-1, total GLP-1, or plasma C-peptide concentrations for the young or older adult cohorts. Despite a significant elevation in plasma nitrite concentration following an acute dose of (11.91 mmol) nitrate, there was no effect on hepatic blood flow, plasma glucose, C-peptide, or incretin concentration in healthy adults.

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Primary study

Unclassified

Year 2017
Authors Wake Forest University
Registry of Trials clinicaltrials.gov
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The objective of this study was to determine the chronic effects of beetroot juice supplementation on the acute (90-minute post nitrate consumption) efficacy of converting dietary nitrate to plasma nitrate and plasma nitrite in healthy middle-to-older aged adults. the investigators were also interested in determining the effect of this intervention on fasting levels of plasma nitrate and nitrite over time. Furthermore, the number of participants classified as \"non-responders\" was determined based on increases in plasma nitrite achieved using tolerable volumes of beetroot juice by other studies.

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Primary study

Unclassified

Year 2020
Registry of Trials clinicaltrials.gov
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Objective: To investigate whether an acute intake of Beetroot Juice (BJ) improved performance factors in a repeated swimming effort at maximum speed in elite swimmers.

Methods: A total of 13 elite swimmers (6 girls and 7 boys) participated in this randomised, double-blind study. In 2 different trials, the swimmers ingested an injection of Beet-It (70 ml placebo (PL) or an injection of Beet-It 70 ml beetroot juice (BJ)) 3 hours before undergoing a 6x100m crawl intermittent maximal speed performance test.

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Primary study

Unclassified

Year 2023
Journal Arquivos brasileiros de cardiologia
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Abstract Background The diet's inorganic nitrate (NO3-) may provide a physiological substrate for reducing nitrate (NO2-) to NO independent of the endothelium. Studies suggest that inorganic NO3- has beneficial effects on cardiovascular health. Objective This study evaluated the acute effects of 500 mL nitrate-rich beetroot juice (BRJ; containing 11.5mmol NO3-) on blood pressure and endothelial function in treated hypertensive patients. Methods A randomized, placebo-controlled, crossover study was conducted in treated hypertensive patients (n=37; women=62%) who underwent clinical and nutritional evaluation and assessment of central hemodynamic parameters and microvascular reactivity. The significance level was p<0.05. Results The mean age was 59±7 years, and mean systolic and diastolic blood pressures were 142±10/83±9mmHg. There was a significant increase in the subendocardial viability ratio (SEVR; 149±25 vs. 165±30%, p<0.001) and reduction in ejection duration (ED; 37±4 vs. 34±4%, p<0.001) in the beetroot phase but no significant SEVR difference in the control phase. The % increase in perfusion (155 vs. 159 %, p=0.042) was significantly increased in the beetroot phase, which was not observed in the control phase. In the beetroot phase, the change in SEVR showed a significant correlation with the change in the area under the curve of post-occlusive reactive hyperemia (AUC-PORH) (r=0.45, p=0.012). The change in ED showed a significant correlation with the post-intervention perfusion peak (r=-0.37, p=0.031) and AUC-PORH (r=-0.36, p=0.046). Conclusions The acute ingestion of BRJ by hypertensive patients resulted in an improvement of endothelial function, which was associated with higher subendocardial viability and performance in myocardial contraction.

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Primary study

Unclassified

Year 2024
Authors University of Vienna
Registry of Trials clinicaltrials.gov
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The purpose of this clinical study in women after menopause is to investigate whether the daily intake of nitrate from beetroot juice over 12 weeks enhances the positive effect of exercise training on vascular function, blood pressure and physical performance.

The risk of cardiovascular diseases (CVD) increases with advancing age and women are particularly affected. In women, the decline in the sex hormone oestrogen in the blood circulation with menopause contributes to impaired vascular function and an increased CVD risk; in part through increased inflammatory processes, oxidative stress, and a reduced body\'s own production of nitric oxide (NO). NO is a signaling molecule that is important for vascular function. Endurance-based exercise training is a key lifestyle strategy to prevent CVD. However, studies indicate that exercise is less effective in terms of its health-promoting adaptations in women after menopause as compared with men of similar age.

This study investigates the effect of exercise training in combination with the intake of nitrate-rich beetroot juice on functions of the cardiovascular system. Nitrate is a nitrogen compound that is found naturally in plant foods (e.g. beetroot juice) and is converted to NO in the human body. Results of previous studies indicate vasodilatory, blood pressure-lowering and performance-enhancing effects as well as positive influences on inflammatory processes and oxidative stress following nitrate intake. The hypothesis is that nitrate intake concomitant to training promotes training adaptations and further improves vascular function, blood pressure and physical performance compared to training without nitrate intake.

For the study, 54 untrained postmenopausal women (with the ages between 45 and 65 years) will be recruited and randomly allocated into two groups. Both groups will undergo 12 weeks of endurance-based exercise training. One group will receive nitrate-rich beetroot juice, and the other nitrate-depleted beetroot juice (as placebo). Vascular function, blood pressure, maximum oxygen uptake, and blood biomarkers for nitrate metabolism, inflammation status and oxidative stress will be examined.

The anticipated study results will provide new insights into whether nitrate as a \'training adjunct\' improves health-promoting training adaptations in women after menopause. The overall aim is to improve the cardiovascular health and performance of middle-aged women and reduce their increased CVD risk.

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Primary study

Unclassified

Year 2019
Journal Contemporary clinical trials communications
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The burden of hypertension in Sub-Saharan African countries is rising. Low-cost and effective interventions are needed to mitigate these alarming trends. No evidence is available on the use of dietary nitrate for treating hypertension in African populations. The objectives of this study are to assess the feasibility and efficacy of using beetroot and folate as a combined dietary intervention to treat Tanzanian adults with pre- and mild to moderate hypertension. This was a three-arm double-blind, placebo-controlled, parallel randomised clinical trial conducted within the Hai Demographic Surveillance Site in the Kilimanjaro region in Tanzania. 48 participants were randomised to one of three groups for a 60-day intervention period. Group 1: Combined dietary intervention (beetroot juice and folate), Group 2: Single dietary intervention (beetroot juice and placebo capsule), and Group 3: Control group (placebo beetroot juice and placebo capsule). The primary outcome of the trial was to evaluate the feasibility of the study in a low-income setting. Trial assessments included resting clinic and ambulatory 24-hr blood pressure measurements, lifestyle and dietary questionnaires and collection of biological samples. Our cohort included 8 (16.7%) males and 40 (83.3%) females with mean age 60.7 years (SD 6.5). The mean (SD) BMI, clinic systolic blood pressure and ambulatory systolic blood pressure at baseline were 27.6 kg/m2 (5.4), 151.0 (19.4), and 140.4 (15.0) mmHg, respectively. Eight (16.7%) participants were classified as pre-hypertensive, 20 (41.7%) as stage-1 hypertensive, and 20 (41.7%) as stage-2 hypertensive. Overall, the results support the feasibility of a study of this nature within a hypertensive African population. Trial registration number: ISRCTN67978523. © 2019 The Author(s)

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Primary study

Unclassified

Year 2014
Authors Bond V , Curry BH , Adams RG , Millis RM , Haddad GE
Journal Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme
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The advent of medical nutrition therapy and nutritional physiology affords the opportunity to link diet to specific cardiovascular mechanisms, suggesting novel treatments for cardiovascular disease. This study tests the hypothesis that beetroot juice increases the plasma nitric oxide (NO) concentration, which is associated with improvements in cardiorespiratory function at rest and during submaximal aerobic exercise. The subjects were 12 healthy, young adult, normotensive African-American females, with a body mass of 61 ± 2 kg, body fat of 28% ± 4%, and peak oxygen consumption of 26 ± 3 mL·kg(-1)·min(-1). The subjects were studied at rest and during cycle ergometer exercise at 40%, 60%, and 80% of peak oxygen consumption. Plasma NO concentration, respiratory quotient (RQ), minute ventilation, systolic and diastolic blood pressure (SBP and DBP), heart rate, and oxygen consumption were compared between isocaloric, isovolumetric placebo control orange juice and experimental beetroot juice treatments on separate days. The beetroot juice treatment increased plasma NO concentration and decreased oxygen consumption, SBP, and the heart rate-SBP product at rest and at 40%, 60%, and 80% of peak oxygen consumption in the absence of significant effects on RQ, minute ventilation, heart rate, and DBP. These findings suggest that, in healthy subjects, beetroot juice treatments increase plasma NO concentration and decrease cardiac afterload and myocardial oxygen demand at rest and during 3 submaximal levels of aerobic exercise. Future studies should determine the cellular and molecular mechanisms responsible for the improvement in cardiorespiratory function associated with dietary nitrate supplementation and whether they translate into better cardiovascular function and exercise tolerance in individuals with a compromised cardiovascular system.

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Primary study

Unclassified

Year 2018
Journal Nitric oxide : biology and chemistry
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Inorganic nitrate (NO3-) supplementation has been shown to improve cardiovascular health indices in healthy adults. The purpose of this study was to investigate how the vehicle of NO3- administration can influence NO3- metabolism and the subsequent blood pressure response. Ten healthy males consumed an acute equimolar dose of NO3- (∼5.76 mmol) in the form of a concentrated beetroot juice drink (BR; 55 mL), a non-concentrated beetroot juice drink (BL; 456 mL) and a solid beetroot flapjack (BF; 60 g). A drink containing soluble beetroot crystals (BC; ∼1.40 mmol NO3-) and a control drink (CON; 70 mL deionised water) were also ingested. BP and plasma, salivary and urinary [NO3-] and [NO2-] were determined before and up to 24 h after ingestion. All NO3--rich vehicles elevated plasma, salivary and urinary nitric oxide metabolites compared with baseline and CON (P<0.05). The peak increases in plasma [NO2-] were greater in BF (371 ± 136 nM) and BR (369 ± 167 nM) compared to BL (283 ± 93 nM; all P<0.05) and BC (232 ± 51 nM). BR, but not BF, BL and BC, reduced systolic (∼5 mmHg) and mean arterial pressure (∼3-4 mmHg; P<0.05), whereas BF reduced diastolic BP (∼4 mmHg; P < 0.05). Although plasma [NO2-] was elevated in all conditions, the consumption of a small, concentrated NO3--rich fluid (BR) was the most effective means of reducing BP. These findings have implications for the use of dietary NO3-supplements when the main objective is to maintain or improve indices of cardiovascular health.

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