September 1, 2017

Beet Root Juice: An Ergogenic Aid for Exercise and the Aging Brain

By:Petrie, M (Petrie, Meredith)1 ] Rejeski, WJ (Rejeski, W. Jack)2 ] Basu, S (Basu, Swati)3 ] Laurienti, PJ (Laurienti, Paul J.)1 ] Marsh, AP (Marsh, Anthony P.)2 ] Norris, JL (Norris, James L.)4 ] Kim-Shapiro, DB (Kim-Shapiro, Daniel B.)3 ] Burdette, JH (Burdette, Jonathan H.)1 ]

JOURNALS OF GERONTOLOGY SERIES A-BIOLOGICAL SCIENCES AND MEDICAL SCIENCES

Volume: 72 

Issue: 9

Pages: 1284-1289

DOI: 10.1093/gerona/glw219

Published: SEP 2017

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Abstract

Background: Exercise has positive neuroplastic effects on the aging brain. It has also been shown that ingestion of beet root juice (BRJ) increases blood flow to the brain and enhances exercise performance. Here, we examined whether there are synergistic effects of BRJ and exercise on neuroplasticity in the aging brain. 


Methods: Peak metabolic equivalent (MET) capacity and resting-state magnetic resonance imaging functional brain network organization are reported on 26 older (mean age = 65.4 years) participants randomly assigned to 6 weeks of exercise + BRJ or exercise + placebo. 

Results: Somatomotor community structure consistency was significantly enhanced in the exercise + BRJ group following the intervention (M-BRJ = -2.27, SE = 0.145, M-Placebo = -2.89, SE = 0.156, p = .007). Differences in second-order connections between the somatomotor cortex and insular cortex were also significant; the exercise + BRJ group (M = 3.28, SE = 0.167) had a significantly lower number of connections than exercise + placebo (M = 3.91, SE = 0.18, p =.017) following the intervention. Evaluation of peak MET capacity revealed a trend for the exercise + BRJ group to have higher MET capacity following the intervention. 

Conclusions: Older adults who exercised and consumed BRJ demonstrated greater consistency within the motor community and fewer secondary connections with the insular cortex compared with those who exercised without BRJ. The exercise + BRJ group had brain networks that more closely resembled those of younger adults, showing the potential enhanced neuroplasticity conferred by combining exercise and BRJ consumption.

April 1, 2017 

The Effect of Dietary Nitrate Supplementation on Endurance Exercise Performance in Healthy Adults: A Systematic Review and Meta-Analysis

 By:McMahon, NF (McMahon, Nicholas F.)1 ] Leveritt, MD (Leveritt, Michael D.)1 ] Pavey, TG (Pavey, Toby G.)2 ]

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SPORTS MEDICINE

Volume: 47

 Issue: 4

 Pages: 735-756

DOI: 10.1007/s40279-016-0617-7

Published: APR 2017

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Abstract

Background Recent research into the use of dietary nitrates and their role in vascular function has led to it becoming progressively more popular amongst athletes attempting to enhance performance. 

Objective The objective of this review was to perform a systematic review and meta-analysis of the literature to evaluate the effect of dietary nitrate (NO3-) supplementation on endurance exercise performance. An additional aim was to determine whether the performance outcomes are affected by potential moderator variables. 

Data sources Relevant databases such as Cochrane Library, Embase, PubMed, Ovid, Scopus and Web of Science were searched for the following search terms 'nitrates OR nitrate OR beetroot OR table beet OR garden beet OR red red AND exercise AND performance' from inception to October 2015. 

Study selection Studies were included if a placebo versus dietary nitrate-only supplementation protocol was able to be compared, and if a quantifiable measure of exercise performance was >= 30 s (for a single bout of exercise or the combined total for multiple bouts). 

Study appraisal and synthesis The literature search identified 1038 studies, with 47 (76 trials) meeting the inclusion criteria. Data from the 76 trials were extracted for inclusion in the meta-analysis. A fixed-effects meta-analysis was conducted for time trial (TT) (n = 28), time to exhaustion (TTE) (n = 22) and graded-exercise test (GXT) (n = 8) protocols. Univariate meta-regression was used to assess potential moderator variables (exercise type, dose duration, NO3- type, study quality, fitness level and percentage nitrite change). 

Results Pooled analysis identified a trivial but non-significant effect in favour of dietary NO3- supplementation [ effect size (ES) = -0.10, 95 % Cl = -0.27 to 0.06, p > 0.05]. TTE trials had a small to moderate statistically significant effect in favour of dietary NO3- supplementation (ES = 0.33, 95 % Cl = 0.15-0.50, p < 0.01). GXT trials had a small but non-significant effect in favour of dietary NO3- supplementation in GXT performance measures (ES = 0.25, 95 % Cl = -0.06 to 0.56, p > 0.05). No significant heterogeneity was detected in the meta-analysis. No statistically significant effects were observed from the meta-regression analysis. 

Conclusion Dietary NO3- supplementation is likely to elicit a positive outcome when testing endurance exercise capacity, whereas dietary NO3- supplementation is less likely to be effective for time-trial performance. Further work is needed to understand the optimal dosing strategies, which population is most likely to benefit, and under which conditions dietary nitrates are likely to be most effective for performance

November 1, 2017

Anti-obesity and anti-diabetic effects of nitrate and nitrite

By:Ghasemi, A (Ghasemi, Asghar)1 ] Jeddi, S (Jeddi, Sajad)1 ]

NITRIC OXIDE-BIOLOGY AND CHEMISTRY

Volume: 70

Pages: 9-24

DOI: 10.1016/j.niox.2017.08.003

Published: NOV 1 2017

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Abstract

Prevalence of obesity is increasing worldwide and type 2 diabetes to date is the most devastating complication of obesity. Decreased nitric oxide bioavailability is a feature of obesity and diabetes that links these two pathologies. Nitric oxide is synthesized both by nitric oxide synthase enzymes from L-arginine and nitric oxide synthase-independent from nitrate/nitrite. Nitric oxide production from nitrate/nitrite could potentially be used for nutrition-based therapy in obesity and diabetes. Nitric oxide deficiency also contributes to pathogeneses of cardiovascular disease and hypertension, which are associated with obesity and diabetes. This review summarizes pathways for nitric oxide production and focuses on the anti-diabetic and anti-obesity effects of the nitrate-nitrite-nitric oxide pathway. In addition to increasing nitric oxide production, nitrate and nitrite reduce oxidative stress, increase adipose tissue browning, have favorable effects on nitric oxide synthase expression, and increase insulin secretion, all effects that are potentially promising for management of obesity and diabetes. Based on current data, it could be suggested that amplifying the nitrate/nitrite nitric oxide pathway is a diet-based strategy for increasing nitric oxide bioavailability and the management of these two interlinked conditions. Adding nitrate/nitrite to drugs that are currently used for managing diabetes (e.g. metformin) and possibly anti obesity drugs may also enhance their efficacy. (C) 2017 Elsevier Inc. All rights reserved.