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Baranauskas MN, Blechschmid TH, Long EB, Coggan AR, Carter SJ. Dietary NO 3- does not enhance endothelial dependent cutaneous vascular conductance in older women. Microvasc Res 2024; 155:104706. [PMID: 38871050 DOI: 10.1016/j.mvr.2024.104706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/24/2024] [Accepted: 06/08/2024] [Indexed: 06/15/2024]
Abstract
Prior work has yet to determine whether the reduction of dietary nitrate (NO3-) to NO, via the enterosalivary pathway, may modify cutaneous vascular conductance (CVC) responses to local heating in older women. Changes occurring with the transition to menopause related to hormonal flux, increased adiposity, and/or decreased physical activity may further compound the negative influence of aging on nitric oxide (NO)-dependent CVC. Herein, we characterized changes in NO-dependent CVC following acute ingestion of 140 mL of NO3--rich beetroot juice in 24 older women (age: 65 ± 5 y, BMI: 31.2 ± 3.7 kg/m2). Red blood cell (RBC) flux was measured continuously via laser-Doppler flowmetry on the dorsal aspect of the forearm during local skin heating to 39 °C/44 °C before and 3 h after NO3- ingestion. NO-dependent changes in CVC were calculated as RBC flux/mean arterial blood pressure at 39 °C and normalized as a proportion of maximal CVC at 44 °C (%CVCmax). Changes (Δ) in fractional exhaled NO (FeNO) following NO3- ingestion were used an index of NO bioavailability. Despite increased FeNO (+81 ± 70 %, P < 0.001), %CVCmax at 39 °C was reduced (-16 ± 10 %, P < 0.001) following NO3- ingestion. A greater reduction in %CVCmax was weakly to moderately associated with higher body fat% (r = 0.45 [0.05-0.72], P = 0.029), central adiposity% (r = 0.50 [0.13-0.75], P = 0.012), neutrophil% (r = 0.42 [0.02-0.70], P = 0.041), and higher neutrophil to lymphocyte ratio (r = 0.49 [0.11-0.75], P = 0.016). These findings demonstrate a single dose of dietary NO3- does not promote CVC responses to local heating in sedentary older women with overweight and obesity. Correlation with multiple biomarkers suggest systemic inflammation may be involved.
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Affiliation(s)
- Marissa N Baranauskas
- Department of Human Physiology & Nutrition, University of Colorado, Colorado Springs, CO, United States of America.
| | - Tyler H Blechschmid
- Department of Kinesiology, School of Public Health, Bloomington, IN, United States of America
| | - Emily B Long
- Department of Kinesiology, School of Public Health, Bloomington, IN, United States of America
| | - Andrew R Coggan
- Department of Kinesiology, Indiana University Indianapolis, Indianapolis, IN, United States of America; Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - Stephen J Carter
- Department of Kinesiology, School of Public Health, Bloomington, IN, United States of America
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2
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Olas B. The Cardioprotective Role of Nitrate-Rich Vegetables. Foods 2024; 13:691. [PMID: 38472804 DOI: 10.3390/foods13050691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/18/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024] Open
Abstract
Nitric oxide (NO) is an inorganic radical produced by both the non-enzymatic nitrate (NO3-)-nitrite (NO2-)-NO pathway and enzymatic reactions catalyzed by nitric oxide synthase (NOS). Also, as nitrate and nitrite from dietary and other endogenous sources can be reduced back to nitric oxide in vivo, the endogenous NO level can be increased through the consumption of nitrate-rich vegetables. Ingestion of dietary NO3- has beneficial effects which have been attributed to a subsequent increase in NO: a signaling molecule that may regulate various systems, including the cardiovascular system. A diet rich in NO3- from green leafy and root vegetables has cardioprotective effects, with beetroot products being particularly good sources of NO3-. For example, various studies have demonstrated a significant increase in nitrite levels (regarded as markers of NO) in plasma after the intake of beetroot juice. The present review describes the current literature concerning the role of nitrate-rich vegetables (especially beetroot products) in the prophylaxis and treatment of cardiovascular diseases (CVDs). This review is based on studies identified in electronic databases, including PubMed, ScienceDirect, Web of Knowledge, Sci Finder, Web of Science, and SCOPUS.
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Affiliation(s)
- Beata Olas
- Department of General Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland
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3
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Gao T, Wang X, Li Y, Ren F. The Role of Probiotics in Skin Health and Related Gut-Skin Axis: A Review. Nutrients 2023; 15:3123. [PMID: 37513540 PMCID: PMC10385652 DOI: 10.3390/nu15143123] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/03/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023] Open
Abstract
Aging skin, wrinkles, pigmentation, and dryness are problems that plague people, and researchers are working to solve them. Recent studies have shown that intestinal microbiota homeostasis can influence skin health, demonstrating the existence of a gut-skin axis. Recently, improving skin health through probiotic interventions has been proposed, and micro-ecological skin care is becoming a popular concept. By regulating skin health and gut-skin axis interactions, probiotics can be used as potential management tools to suppress and improve skin diseases in multiple ways, including decreasing oxidative stress, suppressing inflammatory responses, and keeping immune effects. The purpose of this paper is to provide a comprehensive review of the application and mechanisms of probiotic-mediated gut microbiota homeostasis in skin care and to offer a theoretical basis for the application of probiotics in skin care.
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Affiliation(s)
- Ting Gao
- Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education, Beijing Laboratory of Food Quality and Safety, Department of Nutrition and Health, China Agricultural University, Beijing 100083, China
| | - Xiaoyu Wang
- Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education, Beijing Laboratory of Food Quality and Safety, Department of Nutrition and Health, China Agricultural University, Beijing 100083, China
| | - Yixuan Li
- Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education, Beijing Laboratory of Food Quality and Safety, Department of Nutrition and Health, China Agricultural University, Beijing 100083, China
| | - Fazheng Ren
- Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education, Beijing Laboratory of Food Quality and Safety, Department of Nutrition and Health, China Agricultural University, Beijing 100083, China
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Moreno B, Morencos E, Vicente-Campos D, Muñoz A, González-García J, Veiga S. Effects of beetroot juice intake on repeated performance of competitive swimmers. Front Physiol 2023; 13:1076295. [PMID: 36703935 PMCID: PMC9871287 DOI: 10.3389/fphys.2022.1076295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/28/2022] [Indexed: 01/12/2023] Open
Abstract
Background: Beetroot juice is a sport supplement with a high level of evidence on the physical performance enhancement. However, in swimming, there is no clear data about the effects of beetroot juice on performance. Objective: To investigate whether an acute intake of beetroot juice (BJ) improves the performance of competitive swimmers in a repeated maximum swimming effort. Method: Thirteen national-level swimmers (six females and seven males), participated in this randomized, double-blind crossover study. In two different trials, swimmers ingested a 70-mL placebo shot (.04 mmol NO3 -; PLA) or a 70-mL Beet-It shot (6.4 mmol of NO3 -beet juice [BJ]) 3 h before undergoing a 6 × 100-m front-crawl maximal effort test with 7 min rest between each 100 m. Results: Overall, 100-m times showed no difference between the BJ and PLA groups (p = .364), although a possibly shorter time was observed for BJ in the last repetition (p = .104; mean difference [MD] = -.99 s, mean-based inference [MBI] = 49/51/0). Participants in the BJ condition showed a possibly lower rate of perceived exertion in the first (p = .242, MD = -.85, MBI = 70/28/2) and second repetitions (p = .165, MD = 1.15, MBI = 83/16/1), whereas Total Quality Recovery scale scores were likely higher in the first (p = .110, MD = 1.15, MBI = 83/16/1) and third (p = .082, MD = -.77, MBI = 70/29/1) repetitions compared with those in the PLA group. Blood lactate concentration [La+] levels showed no differences between groups in any of the repetitions (p > .05, unclear), and we observed an increase in 100-m times for both BJ and PLA (BJ: p = .014, MD = -1.51 s; PLA: p = .029, MD = -1.57 s) after the fifth repetition. Conclusion: No clear differences in performance were observed in a 6 × 100-m repeated sprint test by competitive swimmers when supplementing (or not) with BJ. However, there was a trend toward a better recovery between efforts and a better tolerance of fatigue when swimmers ingested BJ.
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Affiliation(s)
- Berta Moreno
- Facultad de Ciencias de la Salud, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Spain,Departamento de Deportes, Universidad Politécnica de Madrid, Madrid, Spain
| | - Esther Morencos
- Facultad de Ciencias de la Salud, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Spain
| | - Davinia Vicente-Campos
- Facultad de Ciencias de la Salud, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Spain
| | - Alejandro Muñoz
- Facultad de Ciencias de la Salud, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Spain
| | - Jaime González-García
- Facultad de Ciencias de la Salud, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Spain
| | - Santiago Veiga
- Departamento de Deportes, Universidad Politécnica de Madrid, Madrid, Spain,*Correspondence: Santiago Veiga,
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dos Santos Pinheiro V, Volino-Souza M, Vieira de Oliveira G, Adam Conte-Junior C, Silveira Alvares T. Effect of high-nitrate beetroot juice consumption on thyroid gland hormones and iodine levels in adults. FOOD BIOSCI 2021. [DOI: 10.1016/j.fbio.2020.100869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Effects of acute dietary nitrate supplementation on cold-induced vasodilation in healthy males. Eur J Appl Physiol 2021; 121:1431-1439. [PMID: 33620545 DOI: 10.1007/s00421-021-04621-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 02/05/2021] [Indexed: 11/27/2022]
Abstract
PURPOSE Cold-induced vasodilation (CIVD) is a paradoxical rise in blood flow to the digits that occur during prolonged cold exposure. CIVD is thought to occur through active vasodilation and/or sympathetic withdrawal, where nitric oxide (NO) may play a key role in mediating these mechanisms. Beetroot juice (BRJ) is high in dietary nitrate (NO3-) which undergoes sequential reduction to nitrite (NO2-) and subsequently NO. Using a double-blind, randomized, crossover design, we examined the effect of acute BRJ supplementation on the CIVD response in 10 healthy males. METHODS Participants had a resting blood pressure measurement taken prior to ingesting 140 mL of nitrate-rich BRJ (13 mmol NO3-) or a NO3--free placebo (PLA). After 2 h, participants immersed their hand in neutral water (~ 35 °C) for 10 min of baseline before cold water immersion (~ 8 °C) for 30 min. Laser-Doppler fluxmetry and skin temperature were measured continuously on the digits. RESULTS Compared to PLA (100 ± 3 mmHg), acute BRJ supplementation significantly reduced mean arterial pressure at -30 min (96 ± 2 mmHg; p = 0.007) and 0 min (94 ± 2 mmHg; p = 0.008). Acute BRJ supplementation had no effect on Laser-Doppler fluxmetry during CIVD (expressed as cutaneous vascular conductance) measured as area under the curve (BRJ: 843 ± 148 PU mmHg-1 s; PLA: 1086 ± 333 PU mmHg-1 s), amplitude (BRJ: 0.60 ± 0.12 PU mmHg-1; PLA: 0.69 ± 0.14 PU mmHg-1), and duration (BRJ: 895 ± 60 s; PLA: 894 ± 46 s). CONCLUSION Acute BRJ supplementation does not augment the CIVD response in healthy males.
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7
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Arnold JT, Bailey SJ, Hodder SG, Fujii N, Lloyd AB. Independent and combined impact of hypoxia and acute inorganic nitrate ingestion on thermoregulatory responses to the cold. Eur J Appl Physiol 2021; 121:1207-1218. [PMID: 33558988 PMCID: PMC7966143 DOI: 10.1007/s00421-021-04602-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 01/10/2021] [Indexed: 11/28/2022]
Abstract
Purpose This study assessed the impact of normobaric hypoxia and acute nitrate ingestion on shivering thermogenesis, cutaneous vascular control, and thermometrics in response to cold stress. Method Eleven male volunteers underwent passive cooling at 10 °C air temperature across four conditions: (1) normoxia with placebo ingestion, (2) hypoxia (0.130 FiO2) with placebo ingestion, (3) normoxia with 13 mmol nitrate ingestion, and (4) hypoxia with nitrate ingestion. Physiological metrics were assessed as a rate of change over 45 min to determine heat loss, and at the point of shivering onset to determine the thermogenic thermoeffector threshold. Result Independently, hypoxia expedited shivering onset time (p = 0.05) due to a faster cooling rate as opposed to a change in central thermoeffector thresholds. Specifically, compared to normoxia, hypoxia increased skin blood flow (p = 0.02), leading to an increased core-cooling rate (p = 0.04) and delta change in rectal temperature (p = 0.03) over 45 min, yet the same rectal temperature at shivering onset (p = 0.9). Independently, nitrate ingestion delayed shivering onset time (p = 0.01), mediated by a change in central thermoeffector thresholds, independent of changes in peripheral heat exchange. Specifically, compared to placebo ingestion, no difference was observed in skin blood flow (p = 0.5), core-cooling rate (p = 0.5), or delta change in rectal temperature (p = 0.7) over 45 min, while nitrate reduced rectal temperature at shivering onset (p = 0.04). No interaction was observed between hypoxia and nitrate ingestion. Conclusion These data improve our understanding of how hypoxia and nitric oxide modulate cold thermoregulation.
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Affiliation(s)
- Josh T Arnold
- Environmental Ergonomics Research Centre, James France Bldg, Design School, Loughborough University, Loughborough, LE11 3TU, UK
| | - Stephen J Bailey
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Simon G Hodder
- Environmental Ergonomics Research Centre, James France Bldg, Design School, Loughborough University, Loughborough, LE11 3TU, UK
| | - Naoto Fujii
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Alex B Lloyd
- Environmental Ergonomics Research Centre, James France Bldg, Design School, Loughborough University, Loughborough, LE11 3TU, UK.
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Cramer MN, Hieda M, Huang M, Moralez G, Crandall CG. Dietary nitrate supplementation does not influence thermoregulatory or cardiovascular strain in older individuals during severe ambient heat stress. Exp Physiol 2020; 105:1730-1741. [PMID: 32816341 DOI: 10.1113/ep088834] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 08/17/2020] [Indexed: 12/16/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does dietary nitrate supplementation with beetroot juice attenuate thermoregulatory and cardiovascular strain in older adults during severe heat stress? What is the main finding and its importance? A 7-day nitrate supplementation regimen lowered resting mean arterial pressure in thermoneutral conditions. During heat stress, core and mean skin temperatures, vasodilatory responses, sweat loss, heart rate and left ventricular function were unchanged, and mean arterial pressure was only transiently reduced, post-supplementation. These data suggest nitrate supplementation with beetroot juice does not mitigate thermoregulatory or cardiovascular strain in heat-stressed older individuals. ABSTRACT This study tested the hypothesis that dietary nitrate supplementation with concentrated beetroot juice attenuates thermoregulatory and cardiovascular strain in older individuals during environmental heat stress. Nine healthy older individuals (six females, three males; aged 67 ± 5 years) were exposed to 42.5 ± 0.1°C and 34.0 ± 0.5% relative humidity conditions for 120 min before (CON) and after 7 days of dietary nitrate supplementation with concentrated beetroot juice (BRJ; 280 ml, ∼16.8 mmol of nitrate daily). Core and skin temperatures, body mass changes (indicative of whole-body sweat loss), skin blood flow and cutaneous vascular conductance, forearm blood flow and vascular conductance, heart rate, arterial blood pressures and indices of cardiac function were measured. The 7-day beetroot juice regimen increased plasma nitrate/nitrite levels from 27.4 ± 15.2 to 477.0 ± 102.5 μmol l-1 (P < 0.01) and lowered resting mean arterial pressure from 90 ± 7 to 83 ± 10 mmHg at baseline under thermoneutral conditions (P = 0.02). However, during subsequent heat stress, no differences in core and skin temperatures, skin blood flow and vascular conductance, forearm blood flow and vascular conductance, whole-body sweat loss, heart rate, and echocardiographic indices of systolic function and diastolic filling were evident following nitrate supplementation (all P > 0.05). Mean arterial pressure was lower in BRJ vs. CON during heat stress (treatment-by-time interaction: P = 0.02). Overall, these findings suggest that dietary nitrate supplementation with concentrated beetroot juice does not attenuate thermoregulatory or cardiovascular strain in older individuals exposed to severe ambient heat stress.
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Affiliation(s)
- Matthew N Cramer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Michinari Hieda
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX, USA.,School of Medicine, Kyushu University, Fukuoka, Japan
| | - Mu Huang
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX, USA.,Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Gilbert Moralez
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX, USA.,Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX, USA
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Wong BJ, Turner CG, Miller JT, Walker DC, Sebeh Y, Hayat MJ, Otis JS, Quyyumi AA. Sensory nerve-mediated and nitric oxide-dependent cutaneous vasodilation in normotensive and prehypertensive non-Hispanic blacks and whites. Am J Physiol Heart Circ Physiol 2020; 319:H271-H281. [PMID: 32559139 DOI: 10.1152/ajpheart.00177.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The purpose of this study was to investigate the effect of race and subclinical elevations in blood pressure (i.e., prehypertension) on cutaneous sensory nerve-mediated and nitric oxide (NO)-dependent vasodilation. We recruited participants who self-identified as either non-Hispanic black (n = 16) or non-Hispanic white (n = 16). Within each group, participants were subdivided as either normotensive (n = 8 per group) or prehypertensive (n = 8 per group). Each participant was instrumented with four intradermal microdialysis fibers: 1) control (lactated Ringer's), 2) 5% lidocaine (sensory nerve inhibition), 3) 20 mM Nω-nitro-l-arginine methyl ester (l-NAME) (NO synthase inhibition), and 4) lidocaine + l-NAME. Skin blood flow was assessed via laser-Doppler flowmetry, and each site underwent local heating from 33°C to 39°C. At the plateau, 20 mM l-NAME were infused at control and lidocaine sites to quantify NO-dependent vasodilation. Maximal vasodilation was induced via 54 mM sodium nitroprusside and local heating to 43°C. Data are means ± SD. Sensory nerve-mediated cutaneous vasodilation was reduced in prehypertensive non-Hispanic white (34 ± 7%) and both non-Hispanic black groups (normotensive, 20 ± 9%, prehypertensive, 24 ± 15%) relative to normotensive non-Hispanic whites (54 ± 12%). NO-dependent vasodilation was also reduced in prehypertensive non-Hispanic white (41 ± 7%) and both non-Hispanic black groups (normotensive, 44 ± 7%, prehypertensive, 19 ± 7%) relative to normotensive non-Hispanic whites (60 ± 11%). The decrease in NO-dependent vasodilation in prehypertensive non-Hispanic blacks was further reduced relative to all other groups. These data suggest subclinical increases in blood pressure adversely affect sensory-mediated and NO-dependent vasodilation in both non-Hispanic blacks and whites.NEW & NOTEWORTHY Overt hypertension is known to reduce cutaneous sensory nerve-mediated and nitric oxide (NO)-dependent vasodilation, but the effect of subclinical increases in blood pressure (i.e., prehypertension) is unknown. The combined effect of race and prehypertension is also unknown. In this study, we found that prehypertension reduces cutaneous sensory nerve-mediated and NO-dependent vasodilation in both non-Hispanic white and black populations, with the greatest reductions observed in prehypertensive non-Hispanic blacks.
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Affiliation(s)
- Brett J Wong
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Casey G Turner
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - James T Miller
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Demetria C Walker
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Yesser Sebeh
- School of Public Health, Georgia State University, Atlanta, Georgia
| | - Matthew J Hayat
- School of Public Health, Georgia State University, Atlanta, Georgia
| | - Jeffrey S Otis
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Arshed A Quyyumi
- Emory Clinical Cardiovascular Research Institute, School of Medicine, Emory University, Atlanta, Georgia
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Zamani H, de Joode MEJR, Hossein IJ, Henckens NFT, Guggeis MA, Berends JE, de Kok TMCM, van Breda SGJ. The benefits and risks of beetroot juice consumption: a systematic review. Crit Rev Food Sci Nutr 2020; 61:788-804. [PMID: 32292042 DOI: 10.1080/10408398.2020.1746629] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Beetroot juice (BRJ) has become increasingly popular amongst athletes aiming to improve sport performances. BRJ contains high concentrations of nitrate, which can be converted into nitric oxide (NO) after consumption. NO has various functions in the human body, including a vasodilatory effect, which reduces blood pressure and increases oxygen- and nutrient delivery to various organs. These effects indicate that BRJ may have relevant applications in prevention and treatment of cardiovascular disease. Furthermore, the consumption of BRJ also has an impact on oxygen delivery to skeletal muscles, muscle efficiency, tolerance and endurance and may thus have a positive impact on sports performances. Aside from the beneficial aspects of BRJ consumption, there may also be potential health risks. Drinking BRJ may easily increase nitrate intake above the acceptable daily intake, which is known to stimulate the endogenous formation of N-nitroso compounds (NOC's), a class of compounds that is known to be carcinogenic and that may also induce several other adverse effects. Compared to studies on the beneficial effects, the amount of data and literature on the negative effects of BRJ is rather limited, and should be increased in order to perform a balanced risk assessment.
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Affiliation(s)
- H Zamani
- Department of Toxicogenomics, GROW-school for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands
| | - M E J R de Joode
- Department of Toxicogenomics, GROW-school for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands
| | - I J Hossein
- Department of Toxicogenomics, GROW-school for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands
| | - N F T Henckens
- Department of Toxicogenomics, GROW-school for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands
| | - M A Guggeis
- Department of Toxicogenomics, GROW-school for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands
| | - J E Berends
- Department of Toxicogenomics, GROW-school for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands
| | - T M C M de Kok
- Department of Toxicogenomics, GROW-school for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands
| | - S G J van Breda
- Department of Toxicogenomics, GROW-school for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands
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Fowler R, Jeffries O, Tallent J, Theis N, Heffernan SM, McNarry MA, Kilduff L, Waldron M. No thermoregulatory or ergogenic effect of dietary nitrate among physically inactive males, exercising above gas exchange threshold in hot and dry conditions. Eur J Sport Sci 2020; 21:370-378. [PMID: 32130090 DOI: 10.1080/17461391.2020.1739144] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The aim of this study was to determine the effect of five days dietary nitrate (NO3-) consumption on exercise tolerance and thermoregulation during cycling in hot, dry conditions. In a double-blind, randomised crossover design, 11 healthy males participated in an exercise tolerance test (Tlim) in the heat (35°C, 28% relative humidity), cycling above the thermoneutral gas exchange threshold, after five days of dietary supplementation, with either NO3-rich beetroot juice (BR; ∼ 9.2 mmol NO3-) or placebo (PLA). Changes in plasma [NO3-] and nitrite [NO2-], core and mean skin temperatures, mean local and whole-body sweat rates, heart rate, perceptual ratings and pulmonary gas exchange were measured during exercise, alongside calorimetric estimations of thermal balance. Mean arterial pressures (MAP) were recorded pre-Tlim. There were no differences in Tlim between conditions (BR = 22.8 ± 8.1 min; Placebo = 20.7 ± 7.9 min) (P = 0.184), despite increases in plasma [NO3-] and [NO2-] (P < 0.001) and a 3.8% reduction in resting MAP (P = 0.004) in the BR condition. There were no other differences in thermoregulatory, cardio-metabolic, perceptual or calorimetric responses to the Tlim between conditions (P > 0.05). Dietary NO3- supplementation had no effect on exercise tolerance or thermoregulation in hot, dry conditions, despite reductions in resting MAP and increases in plasma [NO3-] and [NO2-]. Healthy, yet physically inactive individuals with no known impairments in vasodilatory and sudomotor function do not appear to require BR for ergogenic or thermolytic effects during exercise in the heat.
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Affiliation(s)
- Rebecca Fowler
- Faulty of Sport, Health and Applied Sciences, St Mary's University, London, UK
| | - Owen Jeffries
- School of Biomedical, Nutritional and Sport Sciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Jamie Tallent
- Faulty of Sport, Health and Applied Sciences, St Mary's University, London, UK
| | - Nicola Theis
- School of Sport and Exercise, University of Gloucestershire, Gloucestershire, UK
| | | | | | - Liam Kilduff
- A-STEM, College of Engineering, Swansea University, Swansea, UK.,Welsh Institute of Performance Science, Swansea University, Swansea, UK
| | - Mark Waldron
- A-STEM, College of Engineering, Swansea University, Swansea, UK.,School of Science and Technology, University of New England, Armidale, Australia
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Shepherd AI, Costello JT, Bailey SJ, Bishop N, Wadley AJ, Young-Min S, Gilchrist M, Mayes H, White D, Gorczynski P, Saynor ZL, Massey H, Eglin CM. "Beet" the cold: beetroot juice supplementation improves peripheral blood flow, endothelial function, and anti-inflammatory status in individuals with Raynaud's phenomenon. J Appl Physiol (1985) 2019; 127:1478-1490. [PMID: 31343948 DOI: 10.1152/japplphysiol.00292.2019] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Raynaud's phenomenon (RP) is characterized by recurrent transient peripheral vasospasm and lower nitric oxide (NO) bioavailability in the cold. We investigated the effect of nitrate-rich beetroot juice (BJ) supplementation on 1) NO-mediated vasodilation, 2) cutaneous vascular conductance (CVC) and skin temperature (Tsk) following local cooling, and 3) systemic anti-inflammatory status. Following baseline testing, 23 individuals with RP attended four times, in a double-blind, randomized crossover design, following acute and chronic (14 days) BJ and nitrate-depleted beetroot juice (NDBJ) supplementation. Peripheral Tsk and CVC were measured during and after mild hand and foot cooling, and during transdermal delivery of acetylcholine and sodium nitroprusside. Markers of anti-inflammatory status were also measured. Plasma nitrite concentration ([nitrite]) was increased in the BJ conditions (P < 0.001). Compared with the baseline visit, thumb CVC was greater following chronic-BJ (Δ2.0 flux/mmHg, P = 0.02) and chronic-NDBJ (Δ1.45 flux/mmHg, P = 0.01) supplementation; however, no changes in Tsk were observed (P > 0.05). Plasma [interleukin-10] was greater, pan endothelin and systolic and diastolic blood pressure (BP) were reduced, and forearm endothelial function was improved, by both BJ and NDBJ supplementation (P < 0.05). Acute and chronic BJ and NDBJ supplementation improved anti-inflammatory status, endothelial function and blood pressure (BP). CVC following cooling increased post chronic-BJ and chronic-NDBJ supplementation, but no effect on Tsk was observed. The key findings are that beetroot supplementation improves thumb blood flow, improves endothelial function and anti-inflammatory status, and reduces BP in people with Raynaud's.NEW & NOTEWORTHY This is the first study to examine the effect of dietary nitrate supplementation in individuals with Raynaud's phenomenon. The principal novel findings from this study were that both beetroot juice and nitrate-depleted beetroot juice 1) increased blood flow in the thumb following a cold challenge; 2) enhanced endothelium-dependent and -independent vasodilation in the forearm; 3) reduced systolic and diastolic blood pressure, and pan-endothelin concentration; and 4) improved inflammatory status in comparison to baseline.
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Affiliation(s)
- Anthony I Shepherd
- School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
| | - Joseph T Costello
- School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
| | - Stephen J Bailey
- National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University, Epinal Way, Loughborough, United Kingdom
| | - Nicolette Bishop
- National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University, Epinal Way, Loughborough, United Kingdom.,University Hospitals of Leicester NHS Trust, Infirmary Square, Leicester, United Kingdom
| | - Alex J Wadley
- National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University, Epinal Way, Loughborough, United Kingdom.,University Hospitals of Leicester NHS Trust, Infirmary Square, Leicester, United Kingdom
| | - Steven Young-Min
- Rheumatology Department, Portsmouth Hospitals NHS Trust, Portsmouth, United Kingdom
| | - Mark Gilchrist
- University of Exeter Medical School and NIHR Exeter Clinical Research Facility, Royal Devon and Exeter Hospital, Exeter, Devon, United Kingdom
| | - Harry Mayes
- School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
| | - Danny White
- School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
| | - Paul Gorczynski
- School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
| | - Zoe L Saynor
- School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
| | - Heather Massey
- School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
| | - Clare M Eglin
- School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
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13
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An acute dose of inorganic dietary nitrate does not improve high-intensity, intermittent exercise performance in temperate or hot and humid conditions. Eur J Appl Physiol 2019; 119:723-733. [PMID: 30617465 PMCID: PMC6394696 DOI: 10.1007/s00421-018-04063-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 12/21/2018] [Indexed: 01/13/2023]
Abstract
Purpose Dietary nitrate (NO3−) has repeatedly been shown to improve endurance and intermittent, high-intensity events in temperate conditions. However, the ergogenic effects of dietary NO3− on intermittent exercise performance in hot conditions have yet to be investigated. Methods In a randomised, counterbalanced, double-blind crossover study, 12 recreationally trained males ingested a nitrate-rich beetroot juice shot (BRJ) (6.2 mmol NO3−) or a nitrate-depleted placebo (PLA) (< 0.004 mmol NO3−) 3 h prior to an intermittent sprint test (IST) in temperate (22 °C, 35% RH) and hot conditions (30 °C, 70% RH). The cycle ergometer IST consisted of twenty maximal 6 s sprints interspersed by 114 s of active recovery. Work done, power output, heart rate and RPE were measured throughout; tympanic temperature was measured prior to and upon completion. Results There were no significant effects of supplement on sprint performance in either temperate or hot, humid conditions (p > 0.05). There was a reduced peak (BRJ: 659 ± 100W vs. PLA: 693 ± 139W; p = 0.056) and mean power (BRJ: 543 ± 29W vs. PLA: 575 ± 38W; p = 0.081) following BRJ compared to PLA in the hot and humid condition, but this was not statistically significant. There was no effect of supplement on total work done irrespective of environmental condition. However, ~ 75% of participants experienced performance decreases following BRJ in the hot and humid environment. No differences were observed between trials for tympanic temperature measured at the conclusion of the exercise trial. Conclusion In conclusion, an acute dose of inorganic dietary NO3− does not improve repeated-sprint performance in either temperate, or hot and humid conditions.
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Carlström M, Lundberg JO, Weitzberg E. Mechanisms underlying blood pressure reduction by dietary inorganic nitrate. Acta Physiol (Oxf) 2018; 224:e13080. [PMID: 29694703 DOI: 10.1111/apha.13080] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/28/2018] [Accepted: 04/18/2018] [Indexed: 12/20/2022]
Abstract
Nitric oxide (NO) importantly contributes to cardiovascular homeostasis by regulating blood flow and maintaining endothelial integrity. Conversely, reduced NO bioavailability is a central feature during natural ageing and in many cardiovascular disorders, including hypertension. The inorganic anions nitrate and nitrite are endogenously formed after oxidation of NO synthase (NOS)-derived NO and are also present in our daily diet. Knowledge accumulated over the past two decades has demonstrated that these anions can be recycled back to NO and other bioactive nitrogen oxides via serial reductions that involve oral commensal bacteria and various enzymatic systems. Intake of inorganic nitrate, which is predominantly found in green leafy vegetables and beets, has a variety of favourable cardiovascular effects. As hypertension is a major risk factor of morbidity and mortality worldwide, much attention has been paid to the blood pressure reducing effect of inorganic nitrate. Here, we describe how dietary nitrate, via stimulation of the nitrate-nitrite-NO pathway, affects various organ systems and discuss underlying mechanisms that may contribute to the observed blood pressure-lowering effect.
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Affiliation(s)
- M. Carlström
- Department of Physiology and Pharmacology; Karolinska Institutet; Stockholm Sweden
| | - J. O. Lundberg
- Department of Physiology and Pharmacology; Karolinska Institutet; Stockholm Sweden
| | - E. Weitzberg
- Department of Physiology and Pharmacology; Karolinska Institutet; Stockholm Sweden
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Ashigai H, Mizutani M, Taniguchi Y, Matsukura Y, Nakashima K, Ikeshima E, Yajima H. Roasted Barley Extract (Mugi-cha) Containing Cyclo(d-Phe-l-Pro) Prevents Lowering of the Cutaneous Blood Flow and Skin Temperature under Air Conditioning: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:5901-5906. [PMID: 29792425 DOI: 10.1021/acs.jafc.8b02485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Roasted barley extract (RBE), also known as mugi-cha, is a well-known healthy non-caffeinated beverage, and its health functionality has been widely reported. Our previous clinical study showed that RBE affects the cutaneous blood flow and skin temperature after cold-water immersion and that cyclo(d-Phe-l-Pro) is responsible for its effect. In this study, we investigated whether cyclo(d-Phe-l-Pro)-containing RBE prevents the decrease in the cutaneous blood flow and skin temperature. Subjects remained in the air-conditioned room while ingesting RBE or a placebo. We measured the cutaneous blood flow and skin temperature. We evaluated the effect of RBE administration by two-way repeated measures analysis of variance. A total of 15 subjects were enrolled. The change in cutaneous blood flow in the RBE and placebo groups was -0.79 ± 0.38 and -2.03 ± 0.35 mL min-1 100 g-1, respectively ( p value of 0.041). The change in the skin temperature in the RBE and placebo groups was -1.85 ± 0.35 and -3.02 ± 0.30 °C, respectively ( p value of <0.001). We also did subclass analysis with cold-feeling subjects. For the seven subjects who had cold sensation, the change in the cutaneous blood flow in the RBE and placebo groups was -0.48 ± 0.58 and -2.56 ± 0.48 mL min-1 100 g-1, respectively ( p value of 0.008). The change in the skin temperature in the RBE and placebo groups was -1.46 ± 0.74 and -2.89 ± 0.39 °C, respectively ( p value of 0.009). Thus, RBE containing cyclo(d-Phe-l-Pro) prevents the decrease in the cutaneous blood flow and skin temperature under air conditioning.
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Affiliation(s)
- Hiroshi Ashigai
- Research Laboratories for Health Science and Food Technologies , Kirin Company, Limited , 1-17-1 Namamugi , Tsurumi, Yokohama , Kanagawa 230-8628 , Japan
| | - Mai Mizutani
- Research Laboratories for Health Science and Food Technologies , Kirin Company, Limited , 1-17-1 Namamugi , Tsurumi, Yokohama , Kanagawa 230-8628 , Japan
| | - Yoshimasa Taniguchi
- Development Division, Research Laboratories for Health Science and Food Research , Kirin Company, Limited , 1-13-5 Fukuura , Kanazawa, Yokohama , Kanagawa 236-0004 , Japan
| | - Yasuko Matsukura
- Development Division, Research Laboratories for Health Science and Food Research , Kirin Company, Limited , 1-13-5 Fukuura , Kanazawa, Yokohama , Kanagawa 236-0004 , Japan
| | - Keiko Nakashima
- Research Laboratories for Health Science and Food Technologies , Kirin Company Limited , 1-17-1 Namamugi , Tsurumi, Yokohama , Kanagawa 230-8628 , Japan
| | - Emiko Ikeshima
- Development Division, Research Laboratories for Health Science and Food Research , Kirin Company, Limited , 1-13-5 Fukuura , Kanazawa, Yokohama , Kanagawa 236-0004 , Japan
| | - Hiroaki Yajima
- Research and Development Division, Research and Development Planning Department , Kirin Company Limited , 4-10-2 Nakano , Nakano, Tokyo , Tokyo 164-0001 , Japan
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16
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Amano T, Okushima D, Breese BC, Bailey SJ, Koga S, Kondo N. Influence of dietary nitrate supplementation on local sweating and cutaneous vascular responses during exercise in a hot environment. Eur J Appl Physiol 2018; 118:1579-1588. [DOI: 10.1007/s00421-018-3889-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 05/10/2018] [Indexed: 01/03/2023]
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17
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Kent GL, Dawson B, Cox GR, Abbiss CR, Smith KJ, Croft KD, Lim ZX, Eastwood A, Burke LM, Peeling P. Effect of dietary nitrate supplementation on thermoregulatory and cardiovascular responses to submaximal cycling in the heat. Eur J Appl Physiol 2018; 118:657-668. [DOI: 10.1007/s00421-018-3809-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/15/2018] [Indexed: 12/19/2022]
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18
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Eglin CM, Costello JT, Bailey SJ, Gilchrist M, Massey H, Shepherd AI. Effects of dietary nitrate supplementation on the response to extremity cooling and endothelial function in individuals with cold sensitivity. A double blind, placebo controlled, crossover, randomised control trial. Nitric Oxide 2017; 70:76-85. [PMID: 28941934 DOI: 10.1016/j.niox.2017.09.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/18/2017] [Accepted: 09/18/2017] [Indexed: 01/09/2023]
Abstract
Individuals with cold sensitivity have low peripheral skin blood flow and skin temperature possibly due to reduced nitric oxide (NO•) bioavailability. Beetroot has a high concentration of inorganic nitrate and may increase NO-mediated vasodilation. Using a placebo-controlled, double blind, randomised, crossover design, this study tested the hypotheses that acute beetroot supplementation would increase the rate of cutaneous rewarming following a local cold challenge and augment endothelium-dependent vasodilation in cold sensitive individuals. Thirteen cold sensitive participants completed foot and hand cooling (separately, in 15 °C water for 2 min) with spontaneous rewarming in 30 °C air whilst skin temperature and cutaneous vascular conductance (CVC) were measured (Baseline). On two further separate visits, participants consumed 140 ml of either concentrated beetroot juice (nitrate supplementation) or nitrate-depleted beetroot juice (Placebo) 90 min before resting seated blood pressure was measured. Endothelial function was assessed by measuring CVC at the forearm, finger and foot during iontophoresis of 1% w/v acetylcholine followed by foot and hand cooling as for Baseline. Plasma nitrite concentrations significantly increased in nitrate supplementation compared to Placebo and Baseline (502 ± 246 nmol L-1; 73 ± 45 nmol L-1; 74 ± 49 nmol L-1 respectively; n = 11; P < 0.001). Resting blood pressure and the response to foot and hand cooling did not differ between conditions (all P > 0.05). Nitrate supplementation did not alter endothelial function in the forearm, finger or foot (all P > 0.05) compared to Placebo. Despite a physiologically meaningful rise in plasma nitrite concentrations, acute nitrate supplementation does not alter extremity rewarming, endothelial function or blood pressure in individuals with cold sensitivity.
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Affiliation(s)
- Clare M Eglin
- Department of Sport and Exercise Science, University of Portsmouth, UK
| | - Joseph T Costello
- Department of Sport and Exercise Science, University of Portsmouth, UK
| | - Stephen J Bailey
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Mark Gilchrist
- University of Exeter Medical School, NIHR Exeter Clinical Research Facility, Royal Devon and Exeter Hospital, Exeter, Devon, UK
| | - Heather Massey
- Department of Sport and Exercise Science, University of Portsmouth, UK
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19
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Wong BJ, Keen JT, Levitt EL. Cutaneous reactive hyperaemia is unaltered by dietary nitrate supplementation in healthy humans. Clin Physiol Funct Imaging 2017; 38:772-778. [DOI: 10.1111/cpf.12478] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 10/02/2017] [Indexed: 12/16/2022]
Affiliation(s)
- Brett J Wong
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA.,Department of Kinesiology & Health, Georgia State University, Atlanta, GA, USA
| | - Jeremy T Keen
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Erica L Levitt
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
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Abstract
During the past decade, scientists have made great strides in understanding the microbiome's role in human health. Today, the microbiome has become key in scientific research, therapeutic development, medical treatment, and as a news feature in the media. Most studies have focused on the microbiome of our gut, but recently researchers have turned their attention to other microbiomes, including that of the skin. These studies of gut and skin microbiomes are yielding very informative results, new treatment strategies, and the development of new prebiotic and probiotic products for the treatment of many skin conditions.
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Affiliation(s)
- Mia Maguire
- BioRegenerative Sciences, Inc., 505 Coast Blvd South #208, La Jolla, CA, 92037, USA
| | - Greg Maguire
- BioRegenerative Sciences, Inc., 505 Coast Blvd South #208, La Jolla, CA, 92037, USA.
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Concurrent Beet Juice and Carbohydrate Ingestion: Influence on Glucose Tolerance in Obese and Nonobese Adults. J Nutr Metab 2017; 2017:6436783. [PMID: 28203456 PMCID: PMC5288523 DOI: 10.1155/2017/6436783] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 12/12/2016] [Indexed: 01/09/2023] Open
Abstract
Insulin resistance and obesity are characterized by low nitric oxide (NO) bioavailability. Insulin sensitivity is improved with stimulation of NO generating pathways. Consumption of dietary nitrate (NO3−) increases NO formation, via NO3− reduction to nitrite (NO2−) by oral bacteria. We hypothesized that acute dietary nitrate (beet juice) ingestion improves insulin sensitivity in obese but not in nonobese adults. 12 nonobese (body mass index: 26.3 ± 0.8 kg/m2 (mean ± SE)) and 10 obese adults (34.0 ± 0.8 kg/m2) ingested beet juice, supplemented with 25 g of glucose (carbohydrate load: 75 g), with and without prior use of antibacterial mouthwash to inhibit NO3− reduction to NO2−. Blood glucose concentrations after beet juice and glucose ingestion were greater in obese compared with nonobese adults at 60 and 90 minutes (P = 0.004). Insulin sensitivity, as represented by the Matsuda Index (where higher values reflect greater insulin sensitivity), was lower in obese compared with nonobese adults (P = 0.009). Antibacterial mouthwash rinsing decreased insulin sensitivity in obese (5.7 ± 0.7 versus 4.9 ± 0.6) but not in nonobese (8.1 ± 1.0 versus 8.9 ± 0.9) adults (P = 0.048). In conclusion, insulin sensitivity was improved in obese but not in nonobese adults following coingestion of beet juice and glucose when oral bacteria nitrate reduction was not inhibited. Obese adults may benefit from ingestion of healthy nitrate-rich foods during meals.
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Oral nitrate and citrulline decrease blood pressure and increase vascular conductance in young adults: a potential therapy for heart failure. Eur J Appl Physiol 2016; 116:1651-61. [PMID: 27333912 PMCID: PMC4983290 DOI: 10.1007/s00421-016-3418-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/15/2016] [Indexed: 02/08/2023]
Abstract
Purpose Both inorganic nitrate and citrulline are known to alter the arginine–nitric oxide–nitrate system to increase the bioavailability of nitric oxide with potential benefits in the treatment of heart failure. However, their effects on cardiac electrical activity, vascular compliance and peripheral conductance are less well understood. This study examined the effect of nitrate and citrulline on cardiac electrical activity and blood flow. Methods Young adult subjects (n = 12) were recruited to investigate the effects of acute oral nitrate consumption (8 mg/kg) and chronic citrulline consumption (3 g/day) on cardiac electrical activity measured by ECG recording and blood pressure. Blood flow and vascular compliance were measured by IR-plethysmography at the thumb and the hallux. Results Nitrate (p < 0.05) and citrulline (p < 0.01) consumption both decreased diastolic blood pressure but had no effect on either pulse pressure or rate-pressure product (NS for both). Citrulline also decreased systolic pressure (p < 0.01). Nitrate and citrulline both decreased vascular compliance (p < 0.05 for both) prior to isometric grip exercise, but this was increased for nitrate following exercise (NS). Citrulline decreased R–R interval 9 % (p < 0.05) at rest and increased heart rate (p < 0.05) in addition to significantly decreasing pulse transit duration (6 %; p < 0.05). QRS duration was also decreased by 5 % for citrulline (p < 0.05) with the reduction in R–R interval. Conclusion Both nitrate and citrulline supplementation decreased vascular tone at rest but citrulline also altered sympathovagal balance to increase sympathetic tone. We suggest that both oral nitrate and citrulline may be suitable adjuvants for patients with heart failure to improve peripheral tissue oxygenation.
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23
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Tyler CJ, Coffey TRM, Hodges GJ. Acute l-arginine supplementation has no effect on cardiovascular or thermoregulatory responses to rest, exercise, and recovery in the heat. Eur J Appl Physiol 2015; 116:363-71. [DOI: 10.1007/s00421-015-3295-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 11/05/2015] [Indexed: 12/28/2022]
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