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A critical review of citrulline malate supplementation and exercise performance.
Gough, LA, Sparks, SA, McNaughton, LR, Higgins, MF, Newbury, JW, Trexler, E, Faghy, MA, Bridge, CA
European journal of applied physiology. 2021;(12):3283-3295
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Abstract
As a nitric oxide (NO) enhancer, citrulline malate (CM) has recently been touted as a potential ergogenic aid to both resistance and high-intensity exercise performance, as well as the recovery of muscular performance. The mechanism has been associated with enhanced blood flow to active musculature, however, it might be more far-reaching as either ammonia homeostasis could be improved, or ATP production could be increased via greater availability of malate. Moreover, CM might improve muscle recovery via increased nutrient delivery and/or removal of waste products. To date, a single acute 8 g dose of CM on either resistance exercise performance or cycling has been the most common approach, which has produced equivocal results. This makes the effectiveness of CM to improve exercise performance difficult to determine. Reasons for the disparity in conclusions seem to be due to methodological discrepancies such as the testing protocols and the associated test-retest reliability, dosing strategy (i.e., amount and timing), and the recent discovery of quality control issues with some manufacturers stated (i.e., citrulline:malate ratios). Further exploration of the optimal dose is therefore required including quantification of the bioavailability of NO, citrulline, and malate following ingestion of a range of CM doses. Similarly, further well-controlled studies using highly repeatable exercise protocols with a large aerobic component are required to assess the mechanisms associated with this supplement appropriately. Until such studies are completed, the efficacy of CM supplementation to improve exercise performance remains ambiguous.
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Dietary and Ergogenic Supplementation to Improve Elite Soccer Players' Performance.
Fernandes, H
Annals of nutrition & metabolism. 2021;(4):197-203
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Abstract
BACKGROUND Soccer is an extremely competitive sport, where the most match important moments can be defined in detail. Use of ergogenic supplements can be crucial to improve the performance of a high-performance athlete. Therefore, knowing which ergogenic supplements are important for soccer players can be an interesting strategy to maintain high level in this sport until final and decisive moments of the match. In addition, other supplements, such as dietary supplements, have been studied and increasingly referenced in the scientific literature. But, what if ergogenic supplements were combined with dietary supplements? This review brings some recommendations to improve performance of soccer athletes on the field through dietary and/or ergogenic supplements that can be used simultaneously. SUMMARY Soccer is a competitive sport, where the match important moments can be defined in detail. Thus, use of ergogenic supplements covered in this review can improve performance of elite soccer players maintaining high level in the match until final moments, such as creatine 3-5 g day-1, caffeine 3-6 mg kg-1 BW around 60 min before the match, sodium bicarbonate 0.1-0.4 g kg-1 BW starting from 30 to 180 min before the match, β-alanine 3.2 and 6.4 g day-1 provided in the sustained-release tablets divided into 4 times a day, and nitrate-rich beetroot juice 60 g in 200 mL of water (6 mmol of NO3- L) around 120 min before match or training, including a combination possible with taurine 50 mg kg-1 BW day-1, citrulline 1.2-3.4 g day-1, and arginine 1.2-6 g day-1. Key Messages: Soccer athletes can combine ergogenic and dietary supplements to improve their performance on the field. The ergogenic and dietary supplements used in a scientifically recommended dose did not demonstrate relevant side effects. The use of various evidence-based supplements can add up to further improvement in the performance of the elite soccer players.
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Creatine Supplementation in Children and Adolescents.
Jagim, AR, Kerksick, CM
Nutrients. 2021;(2)
Abstract
Creatine is a popular ergogenic aid among athletic populations with consistent evidence indicating that creatine supplementation also continues to be commonly used among adolescent populations. In addition, the evidence base supporting the therapeutic benefits of creatine supplementation for a plethora of clinical applications in both adults and children continues to grow. Among pediatric populations, a strong rationale exists for creatine to afford therapeutic benefits pertaining to multiple neuromuscular and metabolic disorders, with preliminary evidence for other subsets of clinical populations as well. Despite the strong evidence supporting the efficacy and safety of creatine supplementation among adult populations, less is known as to whether similar physiological benefits extend to children and adolescent populations, and in particular those adolescent populations who are regularly participating in high-intensity exercise training. While limited in scope, studies involving creatine supplementation and exercise performance in adolescent athletes generally report improvements in several ergogenic outcomes with limited evidence of ergolytic properties and consistent reports indicating no adverse events associated with supplementation. The purpose of this article is to summarize the rationale, prevalence of use, performance benefits, clinical applications, and safety of creatine use in children and adolescents.
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Effects of Nitrate Supplementation on Exercise Performance in Humans: A Narrative Review.
Macuh, M, Knap, B
Nutrients. 2021;(9)
Abstract
Nitrates have become increasingly popular for their potential role as an ergogenic aid. The purpose of this article was to review the current scientific evidence of nitrate supplementation on human performance. The current recommendation of nitrate supplementation is discussed, as well as possible health complications associated with nitrate intake for athletes, and dietary strategies of covering nitrate needs through sufficient intake of nitrate-rich foods alone are presented. Pubmed, Scopus, and Web of Science were searched for articles on the effects of nitrate supplementation in humans. Nitrates are an effective ergogenic aid when taken acutely or chronically in the range of ~5-16.8 mmol (~300-1041 mg) 2-3 h before exercise and primarily in the case of exercise duration of ~10-17 min in less trained individuals (VO2max < 65 mL/kg/min). Nitrate needs are most likely meet by ingesting approximately 250-500 g of leafy and root vegetables per day; however, dietary supplements might represent a more convenient and accurate way of covering an athlete's nitrate needs. Athletes should refrain from mouthwash usage when nitrate supplementation benefits are desired. Future research should focus on the potential beneficial effects of nitrate supplementation on brain function, possible negative impacts of chronic nitrate supplementation through different nitrate sources, and the effectiveness of nitrate supplementation on strength and high-intensity intermittent exercise.
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Ketogenic Diets and Exercise Performance.
Harvey, KL, Holcomb, LE, Kolwicz, SC
Nutrients. 2019;(10)
Abstract
The ketogenic diet (KD) has gained a resurgence in popularity due to its purported reputation for fighting obesity. The KD has also acquired attention as an alternative and/or supplemental method for producing energy in the form of ketone bodies. Recent scientific evidence highlights the KD as a promising strategy to treat obesity, diabetes, and cardiac dysfunction. In addition, studies support ketone body supplements as a potential method to induce ketosis and supply sustainable fuel sources to promote exercise performance. Despite the acceptance in the mainstream media, the KD remains controversial in the medical and scientific communities. Research suggests that the KD or ketone body supplementation may result in unexpected side effects, including altered blood lipid profiles, abnormal glucose homeostasis, increased adiposity, fatigue, and gastrointestinal distress. The purpose of this review article is to provide an overview of ketone body metabolism and a background on the KD and ketone body supplements in the context of obesity and exercise performance. The effectiveness of these dietary or supplementation strategies as a therapy for weight loss or as an ergogenic aid will be discussed. In addition, the recent evidence that indicates ketone body metabolism is a potential target for cardiac dysfunction will be reviewed.
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Potential benefits of dietary nitrate ingestion in healthy and clinical populations: A brief review.
McDonagh, STJ, Wylie, LJ, Thompson, C, Vanhatalo, A, Jones, AM
European journal of sport science. 2019;(1):15-29
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Abstract
This article provides an overview of the current literature relating to the efficacy of dietary nitrate (NO3-) ingestion in altering aspects of cardiovascular and metabolic health and exercise capacity in healthy and diseased individuals. The consumption of NO3--rich vegetables, such as spinach and beetroot, have been variously shown to promote nitric oxide bioavailability, reduce systemic blood pressure, enhance tissue blood flow, modulate muscle O2 utilisation and improve exercise tolerance both in normoxia and in hypoxia, as is commonly observed in a number of disease states. NO3- ingestion may, therefore, act as a natural means for augmenting performance and attenuating complications associated with limited O2 availability or transport, hypertension and the metabolic syndrome. Recent studies indicate that dietary NO3- might also augment intrinsic skeletal muscle contractility and improve the speed and power of muscle contraction. Moreover, several investigations suggest that NO3- supplementation may improve aspects of cognitive performance both at rest and during exercise. Collectively, these observations position NO3- as more than a putative ergogenic aid and suggest that increasing natural dietary NO3- intake may act as a prophylactic in countering the predations of senescence and certain cardiovascular-metabolic diseases.
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Timing of ergogenic aids and micronutrients on muscle and exercise performance.
Stecker, RA, Harty, PS, Jagim, AR, Candow, DG, Kerksick, CM
Journal of the International Society of Sports Nutrition. 2019;(1):37
Abstract
The timing of macronutrient ingestion in relation to exercise is a purported strategy to augment muscle accretion, muscle and athletic performance, and recovery. To date, the majority of macronutrient nutrient timing research has focused on carbohydrate and protein intake. However, emerging research suggests that the strategic ingestion of various ergogenic aids and micronutrients may also have beneficial effects. Therefore, the purpose of this narrative review is to critically evaluate and summarize the available literature examining the timing of ergogenic aids (caffeine, creatine, nitrates, sodium bicarbonate, beta-alanine) and micronutrients (iron, calcium) on muscle adaptations and exercise performance. In summary, preliminary data is available to indicate the timing of caffeine, nitrates, and creatine monohydrate may impact outcomes such as exercise performance, strength gains and other exercise training adaptations. Furthermore, data is available to suggest that timing the administration of beta-alanine and sodium bicarbonate may help to minimize known untoward adverse events while maintaining potential ergogenic outcomes. Finally, limited data indicates that timed ingestion of calcium and iron may help with the uptake and metabolism of these nutrients. While encouraging, much more research is needed to better understand how timed administration of these nutrients and others may impact performance, health, or other exercise training outcomes.
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Beyond muscle: the effects of creatine supplementation on brain creatine, cognitive processing, and traumatic brain injury.
Dolan, E, Gualano, B, Rawson, ES
European journal of sport science. 2019;(1):1-14
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Abstract
The ergogenic and therapeutic effects of increasing muscle creatine by supplementation are well-recognized. It appears that similar benefits to brain function and cognitive processing may also be achieved with creatine supplementation, however research in this area is more limited, and important knowledge gaps remain. The purpose of this review is to provide a comprehensive overview of the current state of knowledge about the influence of creatine supplementation on brain function in healthy individuals. It appears that brain creatine is responsive to supplementation, however higher, or more prolonged dosing strategies than those typically used to increase muscle creatine, may be required to elicit an increase in brain creatine. The optimal dosing strategy to induce this response, is currently unknown, and there is an urgent need for studies investigating this. When considering the influence of supplementation strategies on cognitive processes, it appears that creatine is most likely to exert an influence in situations whereby cognitive processes are stressed, e.g. during sleep deprivation, experimental hypoxia, or during the performance of more complex, and thus more cognitively demanding tasks. Evidence exists indicating that increased brain creatine may be effective at reducing the severity of, or enhancing recovery from mild traumatic brain injury, however, only limited data in humans are available to verify this hypothesis, thus representing an exciting area for further research.
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Carnosine in health and disease.
Artioli, GG, Sale, C, Jones, RL
European journal of sport science. 2019;(1):30-39
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Abstract
Carnosine was originally discovered in skeletal muscle, where it exists in larger amounts than in other tissues. The majority of research into the physiological roles of carnosine have been conducted on skeletal muscle. Given this and the potential for muscle carnosine content to be increased with supplementation, there is now a large body of research examining the ergogenic effects (or otherwise) of carnosine. More recent research, however, points towards a potential for carnosine to exert a wider range of physiological effects in other tissues, including the brain, heart, pancreas, kidney and cancer cells. Taken together, this is suggestive of a potential for carnosine to have therapeutic benefits in health and disease, although this is by no means without complication. Herein, we will provide a review of the current literature relating to the potential therapeutic effects of carnosine in health and disease.
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Multi-ingredient pre-workout supplements, safety implications, and performance outcomes: a brief review.
Harty, PS, Zabriskie, HA, Erickson, JL, Molling, PE, Kerksick, CM, Jagim, AR
Journal of the International Society of Sports Nutrition. 2018;(1):41
Abstract
In recent years, a new class of dietary supplements called multi-ingredient pre-workout supplements (MIPS) has increased in popularity. These supplements are intended to be taken prior to exercise and typically contain a blend of ingredients such as caffeine, creatine, beta-alanine, amino acids, and nitric oxide agents, the combination of which may elicit a synergistic effect on acute exercise performance and subsequent training adaptations compared to single ingredients alone. Therefore, the purpose of this article was to review the theoretical rationale and available scientific evidence assessing the potential ergogenic value of acute and chronic ingestion of MIPS, to address potential safety concerns surrounding MIPS supplementation, and to highlight potential areas for future research. Though direct comparisons between formulations of MIPS or between a MIPS and a single ingredient are challenging and often impossible due to the widespread use of "proprietary blends" that do not disclose specific amounts of ingredients in a given formulation, a substantial body of evidence suggests that the acute pre-exercise consumption of MIPS may positively influence muscular endurance and subjective mood, though mixed results have been reported regarding the acute effect of MIPS on force and power production. The chronic consumption of MIPS in conjunction with a periodized resistance training program appears to augment beneficial changes in body composition through increased lean mass accretion. However, the impact of long-term MIPS supplementation on force production, muscular endurance, aerobic performance, and subjective measures is less clear. MIPS ingestion appears to be relatively safe, though most studies that have assessed the safety of MIPS are relatively short (less than eight weeks) and thus more information is needed regarding the safety of long-term supplementation. As with any dietary supplement, the use of MIPS carries implications for the athlete, as many formulations may intentionally contain banned substances as ingredients or unintentionally as contaminants. We suggest that athletes thoroughly investigate the ingredients present in a given MIPS prior to consumption. In conclusion, it appears that multi-ingredient pre-workout supplements have promise as an ergogenic aid for active individuals, though further information is required regarding long-term efficacy and safety in a wider variety of populations.