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Beetroot juice - a suitable post-marathon metabolic recovery supplement?
Stander, Z, Luies, L, van Reenen, M, Howatson, G, Keane, KM, Clifford, T, Stevenson, EJ, Loots, DT
Journal of the International Society of Sports Nutrition. 2021;(1):72
Abstract
BACKGROUND Red beetroot (Beta vulgaris L.) is a multifunctional functional food that reportedly exhibits potent anti-inflammatory, antioxidant, vasodilation, and cellular regulatory properties. This vegetable has gained a fair amount of scientific attention as a possible cost-effective supplement to enhance performance and expedite recovery after physical exercise. To date, no study has investigated the effects of incremental beetroot juice ingestion on the metabolic recovery of athletes after an endurance race. Considering this, as well as the beneficial glucose and insulin regulatory roles of beetroot, this study investigated the effects of beetroot juice supplementation on the metabolic recovery trend of athletes within 48 h after completing a marathon. METHODS By employing an untargeted two-dimensional gas chromatography time-of-flight mass spectrometry approach, serum samples (collected pre-, post-, 24 h post-, and 48 h post-marathon) of 31 marathon athletes that ingested a series (n = 7; 250 ml) of either beetroot juice (n = 15 athletes) or isocaloric placebo (n = 16 athletes) supplements within 48 h post-marathon, were analysed and statistically compared. RESULTS The metabolic profiles of the beetroot-ingesting cohort recovered to a pre-marathon-related state within 48 h post-marathon, mimicking the metabolic recovery trend observed in the placebo cohort. Since random inter-individual variation was observed immediately post-marathon, only metabolites with large practical significance (p-value ≤0.05 and d-value ≥0.5) within 24 h and 48 h post-marathon were considered representative of the effects of beetroot juice on metabolic recovery. These (n = 4) mainly included carbohydrates (arabitol and xylose) and odd-chain fatty acids (nonanoate and undecanoate). The majority of these were attributed to beetroot content and possible microbial fermentation thereof. CONCLUSION Apart from the global metabolic recovery trends of the two opposing cohorts, it appears that beetroot ingestion did not expedite metabolic recovery in athletes within 48 h post-marathon.
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Roles of reversible and irreversible aggregation in sugar processing.
Uchimiya, M
Critical reviews in food science and nutrition. 2017;(6):1206-1214
Abstract
Colloids (1-1000-nm particles) in sugarcane/beet juice originate from non-sucrose impurities (polyphenolic colorants, residual soil, polysaccharides) of the plant materials; additional colloids form during the high temperature processing. Colloids are reactive toward aggregation, sorption, desorption, and redox/hydrolysis/thermal transformation reactions. Both Derjaguin-Landau-Verwey-Overbeek (DLVO; van der Waals and electrostatic forces) and non-DLVO (involving hydrophilic colloids) interactions control the stability of colloids in juice. Heteroaggregation causes a range of feedstock and end product problems, including turbidity, viscosity, color, gelling, crystallization, starch ghost, and heat transfer problems. Even after intensive clarification and refining, trace colloidal impurities on white (refined) sugar remain to cause a problem known as acid beverage floc. Acid beverage floc is an example of DLVO-type aggregation of oppositely charged particles at decreased pH. Examples of irreversible aggregates include starch ghost and recalcitrant organomineral composites formed at elevated temperature that resist heat transfer. Fundamental knowledge in aggregation kinetics is necessary to predict the occurrence of undesirable aggregates, as pH, ionic strength, temperature, and sucrose concentration change during the processing of sugarcane/beet juice.
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The Nitrate-Independent Blood Pressure-Lowering Effect of Beetroot Juice: A Systematic Review and Meta-Analysis.
Bahadoran, Z, Mirmiran, P, Kabir, A, Azizi, F, Ghasemi, A
Advances in nutrition (Bethesda, Md.). 2017;(6):830-838
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Abstract
Beetroot is considered a complementary treatment for hypertension because of its high content of inorganic NO3 This systematic review and meta-analysis aimed to clarify several aspects of beetroot juice supplementation on systolic blood pressure (SBP) and diastolic blood pressure (DBP). We searched PubMed, Scopus, and Embase databases, and the reference lists of previous reviews. Randomized clinical trials that investigated the effects of beetroot juice on resting blood pressure in humans were recruited for quality assessment, meta-analyses, subgroup analyses, and meta-regressions; of these, 22 were conducted between 2009 and 2017 and included a total of 47 intervention (n = 650) and 43 control (n = 598) groups. Overall, SBP (-3.55 mm Hg; 95% CI: -4.55, -2.54 mm Hg) and DBP (-1.32 mm Hg; 95% CI: -1.97, -0.68 mm Hg) were significantly lower in the beetroot juice-supplemented groups than in the control groups. The mean difference of SBP was larger between beetroot juice-supplemented and control groups in the longer than in the shorter (≥14 compared with <14 d) study durations (-5.11 compared with -2.67 mm Hg) and the highest compared with the lowest (500 compared with 70 and 140 mL/d) doses of beetroot juice (-4.78 compared with -2.37 mm Hg). A positive correlation was observed between beetroot juice doses and the mean differences of blood pressures. In contrast, a smaller effect size of blood pressures was observed after supplementation with higher NO3 (milligrams per 100 mL beetroot juice). A weak effect size was observed in a meta-analysis of trials that used NO3-depleted beetroot juice as a placebo compared with other interventions (-3.09 compared with -4.51 mm Hg for SBP and -0.81 compared with -2.01 mm Hg for DBP). Our results demonstrate the blood pressure-lowering effects of beetroot juice and highlight its potential NO3-independent effects.
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Performance and Health Benefits of Dietary Nitrate Supplementation in Older Adults: A Systematic Review.
Stanaway, L, Rutherfurd-Markwick, K, Page, R, Ali, A
Nutrients. 2017;(11)
Abstract
Supplementation with nitrate (NO₃-)-rich beetroot juice has been shown to improve exercise performance and cardiovascular (CV) responses, due to an increased nitric oxide (NO) availability. However, it is unclear whether these benefits are greater in older adults who have an age-related decrease in NO and higher risk of disease. This systematic review examines 12 randomised, crossover, control trials, investigating food-based NO₃- supplementation in older adults and its potential benefits on physiological and cognitive performances, and CV, cerebrovascular and metabolic health. Four studies found improvements in physiological performance (time to exhaustion) following dietary NO₃- supplementation in older adults. Benefits on cognitive performance were unclear. Six studies reported improvements in CV health (blood pressure and blood flow), while six found no improvement. One study showed improvements in cerebrovascular health and two found no improvement in metabolic health. The current literature indicates positive effects of dietary NO₃- supplementation in older adults on physiological performance, with some evidence indicating benefits on cardiovascular and cerebrovascular health. Effects on cognitive performance were mixed and studies on metabolic health indicated no benefit. However, there has been limited research conducted on the effects of dietary NO₃- supplementation in older adults, thus, further study, utilising a randomised, double-blind, control trial design, is warranted.
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"Beet-ing" the Mountain: A Review of the Physiological and Performance Effects of Dietary Nitrate Supplementation at Simulated and Terrestrial Altitude.
Shannon, OM, McGawley, K, Nybäck, L, Duckworth, L, Barlow, MJ, Woods, D, Siervo, M, O'Hara, JP
Sports medicine (Auckland, N.Z.). 2017;(11):2155-2169
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Abstract
Exposure to altitude results in multiple physiological consequences. These include, but are not limited to, a reduced maximal oxygen consumption, drop in arterial oxygen saturation, and increase in muscle metabolic perturbations at a fixed sub-maximal work rate. Exercise capacity during fixed work rate or incremental exercise and time-trial performance are also impaired at altitude relative to sea level. Recently, dietary nitrate (NO3-) supplementation has attracted considerable interest as a nutritional aid during altitude exposure. In this review, we summarise and critically evaluate the physiological and performance effects of dietary NO3- supplementation during exposure to simulated and terrestrial altitude. Previous investigations at simulated altitude indicate that NO3- supplementation may reduce the oxygen cost of exercise, elevate arterial and tissue oxygen saturation, improve muscle metabolic function, and enhance exercise capacity/performance. Conversely, current evidence suggests that NO3- supplementation does not augment the training response at simulated altitude. Few studies have evaluated the effects of NO3- at terrestrial altitude. Current evidence indicates potential improvements in endothelial function at terrestrial altitude following NO3- supplementation. No effects of NO3- supplementation have been observed on oxygen consumption or arterial oxygen saturation at terrestrial altitude, although further research is warranted. Limitations of the present body of literature are discussed, and directions for future research are provided.
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Enjoy your heart-beets. The role of dietary inorganic nitrate in cardiovascular health.
Beręsewicz, A, Gajos-Draus, A
Kardiologia polska. 2016;(5):403-10
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Dietary Nitrate and Skeletal Muscle Contractile Function in Heart Failure.
Coggan, AR, Peterson, LR
Current heart failure reports. 2016;(4):158-65
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Heart failure (HF) patients suffer from exercise intolerance that diminishes their ability to perform normal activities of daily living and hence compromises their quality of life. This is due largely to detrimental changes in skeletal muscle mass, structure, metabolism, and function. This includes an impairment of muscle contractile performance, i.e., a decline in the maximal force, speed, and power of muscle shortening. Although numerous mechanisms underlie this reduction in contractility, one contributing factor may be a decrease in nitric oxide (NO) bioavailability. Consistent with this, recent data demonstrate that acute ingestion of NO3 (-)-rich beetroot juice, a source of NO via the NO synthase-independent enterosalivary pathway, markedly increases maximal muscle speed and power in HF patients. This review discusses the role of muscle contractile dysfunction in the exercise intolerance characteristic of HF, and the evidence that dietary NO3 (-) supplementation may represent a novel and simple therapy for this currently underappreciated problem.
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Effects of inorganic nitrate and beetroot supplementation on endothelial function: a systematic review and meta-analysis.
Lara, J, Ashor, AW, Oggioni, C, Ahluwalia, A, Mathers, JC, Siervo, M
European journal of nutrition. 2016;(2):451-459
Abstract
BACKGROUND Diets rich in inorganic nitrate are associated with lower blood pressure, an effect that may be mediated by an improvement of endothelial function (EF). Therefore, a systematic review and meta-analysis of randomised controlled trials (RCTs) were conducted to examine the effects of inorganic nitrate and beetroot supplementation on measures of EF. METHODS MEDLINE, EMBASE and Scopus databases were searched from inception until November 2014. Specific inclusion criteria were as follows: (1) RCTs; (2) trials comparing inorganic nitrate or beetroot supplementation with placebo control groups; and (3) trials reporting effects of these interventions on outcomes of vascular function. Random-effect models were used to assess the pooled effect sizes showed as standardised mean differences (SMD). RESULTS Nine crossover trials and three parallel trials met our inclusion criteria. The trials were conducted between 2008 and 2014 and included a total of 246 participants with 10-64 participants per study. The duration of each intervention ranged from 1.5 h to 28 days. Inorganic nitrate and beetroot consumption was associated with an improvement in vascular function (SMD 0.36; 95 % CI 0.16, 0.56; P < 0.001). The effect on EF was significantly associated with the dose of inorganic nitrate (β = 0.04, SE = 0.01, P < 0.001), age (β = -0.01, SE = 0.004, P = 0.02), baseline BMI (β = -0.04, SE = 0.02, P = 0.05) and systolic BP (β = -0.01, SE = 0.005, P = 0.02). CONCLUSIONS Inorganic nitrate and beetroot supplementation was associated with beneficial effects on EF. These effects appear to be reduced in older subjects and in subjects with greater cardiometabolic risk.
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Inorganic nitrate and beetroot juice supplementation reduces blood pressure in adults: a systematic review and meta-analysis.
Siervo, M, Lara, J, Ogbonmwan, I, Mathers, JC
The Journal of nutrition. 2013;(6):818-26
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Diets including food products rich in inorganic nitrate are associated with lower blood pressure (BP). The evidence for the BP-lowering effects of inorganic nitrate and beetroot in randomized clinical trials has not been systematically assessed. The objective was to conduct a systematic review and meta-analysis of randomized clinical trials that examined the effects of inorganic nitrate and beetroot supplementation on BP. Medline, EMBASE, and Scopus databases were searched from inception to February 2013. The specific inclusion criteria were: 1) randomized clinical trials; 2) trials reporting effects on systolic or diastolic BP or both; and 3) trials comparing inorganic nitrate or beetroot juice supplementation with placebo control groups. Random-effects models were used to assess the pooled BP effect sizes. Sixteen trials met the eligibility criteria for the systematic review. All studies had a crossover study design. The trials were conducted between 2006 and 2012 and included a total of 254 participants with 7-30 participants/study. The duration of each intervention ranged from 2 h to 15 d. Inorganic nitrate and beetroot juice consumption were associated with greater changes in systolic BP [-4.4 mm Hg (95% CI: -5.9, -2.8); P < 0.001] than diastolic BP [-1.1 mm Hg (95% CI: -2.2, 0.1); P = 0.06]. The meta-regression showed an association between daily dose of inorganic nitrate and changes in systolic BP (P < 0.05). Inorganic nitrate and beetroot juice supplementation was associated with a significant reduction in systolic BP. These findings need to be tested in long-term trials and in individuals at greater cardiovascular risk.
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Nutritional and functional potential of Beta vulgaris cicla and rubra.
Ninfali, P, Angelino, D
Fitoterapia. 2013;:188-99
Abstract
Swiss chard (Beta vulgaris cicla, BVc) and beetroot (Beta vulgaris rubra, BVr) are vegetables of the Chenopodiaceae family, widely consumed in traditional western cooking. These vegetables represent a highly renewable and cheap source of nutrients. They can be cultivated in soils with scarce organic material and little light and water. BVc and BVr have a long history of use in folk medicine. Modern pharmacology shows that BVc extracts possess antihypertensive and hypoglycaemic activity as well as excellent antioxidant activity. BVc contains apigenin flavonoids, namely vitexin, vitexin-2-O-rhamnoside and vitexin-2-O-xyloside, which show antiproliferative activity on cancer cell lines. BVr contains secondary metabolites, called betalains, which are used as natural dyes in food industry and show anticancer activity. In this light, BVc and BVr can be considered functional foods. Moreover, the promising results of their phytochemicals in health protection suggest the opportunity to take advantage of the large availability of this crop for purification of chemopreventive molecules to be used in functional foods and nutraceutical products.