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Li G, Li Z, Liu J. Amino acids regulating skeletal muscle metabolism: mechanisms of action, physical training dosage recommendations and adverse effects. Nutr Metab (Lond) 2024; 21:41. [PMID: 38956658 PMCID: PMC11220999 DOI: 10.1186/s12986-024-00820-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 06/24/2024] [Indexed: 07/04/2024] Open
Abstract
Maintaining skeletal muscle mass is important for improving muscle strength and function. Hence, maximizing lean body mass (LBM) is the primary goal for both elite athletes and fitness enthusiasts. The use of amino acids as dietary supplements is widespread among athletes and physically active individuals. Extensive literature analysis reveals that branched-chain amino acids (BCAA), creatine, glutamine and β-alanine may be beneficial in regulating skeletal muscle metabolism, enhancing LBM and mitigating exercise-induced muscle damage. This review details the mechanisms of these amino acids, offering insights into their efficacy as supplements. Recommended dosage and potential side effects are then outlined to aid athletes in making informed choices and safeguard their health. Lastly, limitations within the current literature are addressed, highlighting opportunities for future research.
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Affiliation(s)
- Guangqi Li
- School of Physical Education, Northeast Normal university, No. 5268, Renmin Street, Changchun city, Jilin province, 130024, People's Republic of China
| | - Zhaojun Li
- Gaomi Municipal Center for Disease Control and Prevention, Gaomi city, Shandong, People's Republic of China
| | - Junyi Liu
- School of Physical Education, Northeast Normal university, No. 5268, Renmin Street, Changchun city, Jilin province, 130024, People's Republic of China.
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2
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Treibmann S, Venema K, Henle T. Glycation reactions of methylglyoxal during digestion in a dynamic, in vitro model of the upper gastrointestinal tract (TIM-1). Food Sci Nutr 2024; 12:4702-4712. [PMID: 39055211 PMCID: PMC11266905 DOI: 10.1002/fsn3.4118] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 03/02/2024] [Accepted: 03/09/2024] [Indexed: 07/27/2024] Open
Abstract
The 1,2-dicarbonyl compound methylglyoxal (MGO) can react with and thereby impair the function of proteins and DNA, leading to pathophysiological pathways in vivo. However, studies on the bioavailability of dietary MGO and its reactions during digestion have diverging results. Therefore, simulated digestion experiments of MGO, protein, and creatine were performed in the dynamic, in vitro model of the upper gastrointestinal tract (TIM-1). This multicompartment model continuously adjusts pH values and has realistic gastrointestinal transit times while also removing water and metabolites by dialysis. Samples were analyzed with HPLC-UV for MGO and HPLC-MS/MS for creatine and glycated amino compounds. MGO reacted with creatine during simulated digestion in TIM-1 to form the hydroimidazolone MG-HCr in similar amounts as in a human intervention study. 28%-69% of MGO from the meal were passively absorbed in TIM-1, depending on the addition of creatine and protein. Simultaneous digestion of MGO with ovalbumin led to the formation of the lysine adduct N ε -carboxyethyllysine (CEL) and the methylglyoxal-derived hydroimidazolone of arginine (MG-H1). The formation of both compounds decreased with added creatine. Hence, glycation compounds are formed during digestion and significantly contribute to other ingested dietary glycation compounds, whose physiological consequences are critically discussed.
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Affiliation(s)
| | - Koen Venema
- Centre for Healthy Eating & Food Innovation (HEFI)Maastricht University – Campus VenloVenloThe Netherlands
| | - Thomas Henle
- Chair of Food ChemistryTechnische Universität DresdenDresdenGermany
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3
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Sandkühler JF, Kersting X, Faust A, Königs EK, Altman G, Ettinger U, Lux S, Philipsen A, Müller H, Brauner J. The effects of creatine supplementation on cognitive performance-a randomised controlled study. BMC Med 2023; 21:440. [PMID: 37968687 PMCID: PMC10647179 DOI: 10.1186/s12916-023-03146-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 10/31/2023] [Indexed: 11/17/2023] Open
Abstract
BACKGROUND Creatine is an organic compound that facilitates the recycling of energy-providing adenosine triphosphate (ATP) in muscle and brain tissue. It is a safe, well-studied supplement for strength training. Previous studies have shown that supplementation increases brain creatine levels, which might increase cognitive performance. The results of studies that have tested cognitive performance differ greatly, possibly due to different populations, supplementation regimens, and cognitive tasks. This is the largest study on the effect of creatine supplementation on cognitive performance to date. METHODS Our trial was preregistered, cross-over, double-blind, placebo-controlled, and randomised, with daily supplementation of 5 g for 6 weeks each. We tested participants on Raven's Advanced Progressive Matrices (RAPM) and on the Backward Digit Span (BDS). In addition, we included eight exploratory cognitive tests. About half of our 123 participants were vegetarians and half were omnivores. RESULTS Bayesian evidence supported a small beneficial effect of creatine. The creatine effect bordered significance for BDS (p = 0.064, η2P = 0.029) but not RAPM (p = 0.327, η2P = 0.008). There was no indication that creatine improved the performance of our exploratory cognitive tasks. Side effects were reported significantly more often for creatine than for placebo supplementation (p = 0.002, RR = 4.25). Vegetarians did not benefit more from creatine than omnivores. CONCLUSIONS Our study, in combination with the literature, implies that creatine might have a small beneficial effect. Larger studies are needed to confirm or rule out this effect. Given the safety and broad availability of creatine, this is well worth investigating; a small effect could have large benefits when scaled over time and over many people. TRIAL REGISTRATION The trial was prospectively registered (drks.de identifier: DRKS00017250, https://osf.io/xpwkc/ ).
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Affiliation(s)
- Julia Fabienne Sandkühler
- Department of Psychology, University of Bonn, Kaiser-Karl-Ring 9, 53111, Bonn, Germany.
- Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany.
| | - Xenia Kersting
- Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany
- Department of Psychiatry and Psychotherapy, University Medical Center, Mainz, Germany
| | - Annika Faust
- Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany
| | - Eva Kathrin Königs
- Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany
| | - George Altman
- Manchester University NHS Foundation Trust, Manchester, UK
| | - Ulrich Ettinger
- Department of Psychology, University of Bonn, Kaiser-Karl-Ring 9, 53111, Bonn, Germany
| | - Silke Lux
- Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany
| | - Alexandra Philipsen
- Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany
| | - Helge Müller
- Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany
- Department of Health, Witten/Herdecke University, Witten, Germany
| | - Jan Brauner
- Department of Health, Witten/Herdecke University, Witten, Germany
- Department of Computer Science, University of Oxford, Oxford, UK
- Future of Humanity Institute, University of Oxford, Oxford, UK
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4
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Eneanya ND, Adingwupu OM, Kostelanetz S, Norris KC, Greene T, Lewis JB, Beddhu S, Boucher R, Miao S, Chaudhari J, Levey AS, Inker LA. Social Determinants of Health and Their Impact on the Black Race Coefficient in Serum Creatinine-Based Estimation of GFR: Secondary Analysis of MDRD and CRIC Studies. Clin J Am Soc Nephrol 2023; 18:446-454. [PMID: 36723299 PMCID: PMC10103283 DOI: 10.2215/cjn.0000000000000109] [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: 09/28/2022] [Accepted: 01/20/2023] [Indexed: 02/02/2023]
Abstract
BACKGROUND The cause for differences in serum creatinine between Black and non-Black individuals incorporated into prior GFR-estimating equations is not understood. We explored whether social determinants of health can account for this difference. METHODS We conducted a secondary analysis of baseline data of the Modification of Diet in Renal Disease and Chronic Renal Insufficiency Cohort studies ( N =1628 and 1423, respectively). Data in both study cohorts were stratified by race (Black versus non-Black). We first evaluated the extent to which the coefficient of Black race in estimating GFR from creatinine is explained by correlations of race with social determinants of health and non-GFR determinants of creatinine. Second, we evaluated whether the difference between race groups in adjusted mean creatinine can be explained by social determinants of health and non-GFR determinants of creatinine. RESULTS In models regressing measured GFR on creatinine, age, sex, and race, the coefficient for Black race was 21% (95% confidence interval, 0.176 to 0.245) in Modification of Diet in Renal Disease and 13% (95% confidence interval, 0.097 to 0.155) in the Chronic Renal Insufficiency Cohort and was not attenuated by the addition of social determinants of health, alone or in combination. In both studies, the coefficient for Black race was larger at lower versus higher income levels. In models, regressing creatinine on measured GFR, age, and sex, mean creatinine was higher in Black versus non-Black participants in both studies, with no effect of social determinants of health. CONCLUSIONS Adjustment for selected social determinants of health did not influence the relationship between Black race and creatinine-based estimated GFR.
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Affiliation(s)
- Nwamaka D. Eneanya
- Department of Medicine, Renal-Electrolyte and Hypertension Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ogechi M. Adingwupu
- Department of Medicine, Division of Nephrology, Tufts Medical Center, Boston, Massachusetts
| | | | - Keith C. Norris
- Department of Medicine, VA Greater Los Angeles Healthcare System, David Geffen School of Medicine, University of California, Los Angeles, California
| | - Tom Greene
- Division of Epidemiology, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Julia B. Lewis
- Department of Medicine, Division of Nephrology, Vanderbilt University, Nashville, Tennessee
| | - Srinivasan Beddhu
- Department of Internal Medicine, Division of Nephrology & Hypertension, University of Utah Health Sciences, Salt Lake City, Utah
| | - Robert Boucher
- Department of Internal Medicine, Division of Nephrology & Hypertension, University of Utah Health Sciences, Salt Lake City, Utah
| | - Shiyuan Miao
- Department of Medicine, Division of Nephrology, Tufts Medical Center, Boston, Massachusetts
| | - Juhi Chaudhari
- Department of Medicine, Division of Nephrology, Tufts Medical Center, Boston, Massachusetts
| | - Andrew S. Levey
- Department of Medicine, Division of Nephrology, Tufts Medical Center, Boston, Massachusetts
| | - Lesley A. Inker
- Department of Medicine, Division of Nephrology, Tufts Medical Center, Boston, Massachusetts
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5
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Tomczyńska-Mleko M, Mleko S, Terpiłowski K, Pérez-Huertas S, Nishinari K. Aerated whey protein gels as a controlled release system of creatine investigated in an artificial stomach. INNOV FOOD SCI EMERG 2022. [DOI: 10.1016/j.ifset.2022.103060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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6
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Candow DG, Forbes SC, Roberts MD, Roy BD, Antonio J, Smith-Ryan AE, Rawson ES, Gualano B, Roschel H. Creatine O'Clock: Does Timing of Ingestion Really Influence Muscle Mass and Performance? Front Sports Act Living 2022; 4:893714. [PMID: 35669557 PMCID: PMC9163789 DOI: 10.3389/fspor.2022.893714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
It is well-established that creatine supplementation augments the gains in muscle mass and performance during periods of resistance training. However, whether the timing of creatine ingestion influences these physical and physiological adaptations is unclear. Muscle contractions increase blood flow and possibly creatine transport kinetics which has led some to speculate that creatine in close proximity to resistance training sessions may lead to superior improvements in muscle mass and performance. Furthermore, creatine co-ingested with carbohydrates or a mixture of carbohydrates and protein that alter insulin enhance creatine uptake. The purpose of this narrative review is to (i) discuss the purported mechanisms and variables that possibly justify creatine timing strategies, (ii) to critically evaluate research examining the strategic ingestion of creatine during a resistance training program, and (iii) provide future research directions pertaining to creatine timing.
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Affiliation(s)
- Darren G. Candow
- Faculty of Kinesiology and Health Studies, University of Regina, Regina, SK, Canada
| | - Scott C. Forbes
- Department of Physical Education Studies, Faculty of Education, Brandon University, Brandon, MB, Canada
- *Correspondence: Scott C. Forbes
| | | | - Brian D. Roy
- Department of Kinesiology, Brock University, St. Catharines, ON, Canada
| | - Jose Antonio
- Department of Health and Human Performance, Nova Southeastern University, Fort Lauderdale, FL, United States
| | - Abbie E. Smith-Ryan
- Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Eric S. Rawson
- Department of Health, Nutrition, and Exercise Science, Messiah University, Mechanicsburg, PA, United States
| | - Bruno Gualano
- Applied Physiology & Nutrition Research Group, Rheumatology Division, Faculty of Medicine FMUSP, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Hamilton Roschel
- Applied Physiology & Nutrition Research Group, Rheumatology Division, Faculty of Medicine FMUSP, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
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7
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Supplementation and Performance for Wheelchair Athletes: A Systematic Review. Adapt Phys Activ Q 2022; 39:268-282. [PMID: 34758458 DOI: 10.1123/apaq.2020-0241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 08/20/2021] [Accepted: 09/02/2021] [Indexed: 12/29/2022] Open
Abstract
This systematic review aimed to identify nutritional interventions and supplements that improve the performance for wheelchair athletes. Intervention trials involving high-performance wheelchair athletes were analyzed, including those that comprised a nutritional intervention, defined as any intervention related to food, beverages, and supplementation aiming at evaluating the performance of wheelchair athletes. Of the included studies, four evaluated caffeine supplementation, of which one also evaluated sodium citrate supplementation; two studies evaluated vitamin D supplementation; one study assessed creatine monohydrate supplementation; and one assessed carbohydrate supplementation. Most studies were conducted on athletes with spinal cord injury. Athletes who consumed caffeine exhibited an improvement in performance, but this finding is not strong enough to become a recommendation.
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Kreider RB, Jäger R, Purpura M. Bioavailability, Efficacy, Safety, and Regulatory Status of Creatine and Related Compounds: A Critical Review. Nutrients 2022; 14:nu14051035. [PMID: 35268011 PMCID: PMC8912867 DOI: 10.3390/nu14051035] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 02/23/2022] [Accepted: 02/25/2022] [Indexed: 12/12/2022] Open
Abstract
In 2011, we published a paper providing an overview about the bioavailability, efficacy, and regulatory status of creatine monohydrate (CrM), as well as other “novel forms” of creatine that were being marketed at the time. This paper concluded that no other purported form of creatine had been shown to be a more effective source of creatine than CrM, and that CrM was recognized by international regulatory authorities as safe for use in dietary supplements. Moreover, that most purported “forms” of creatine that were being marketed at the time were either less bioavailable, less effective, more expensive, and/or not sufficiently studied in terms of safety and/or efficacy. We also provided examples of several “forms” of creatine that were being marketed that were not bioavailable sources of creatine or less effective than CrM in comparative effectiveness trials. We had hoped that this paper would encourage supplement manufacturers to use CrM in dietary supplements given the overwhelming efficacy and safety profile. Alternatively, encourage them to conduct research to show their purported “form” of creatine was a bioavailable, effective, and safe source of creatine before making unsubstantiated claims of greater efficacy and/or safety than CrM. Unfortunately, unsupported misrepresentations about the effectiveness and safety of various “forms” of creatine have continued. The purpose of this critical review is to: (1) provide an overview of the physiochemical properties, bioavailability, and safety of CrM; (2) describe the data needed to substantiate claims that a “novel form” of creatine is a bioavailable, effective, and safe source of creatine; (3) examine whether other marketed sources of creatine are more effective sources of creatine than CrM; (4) provide an update about the regulatory status of CrM and other purported sources of creatine sold as dietary supplements; and (5) provide guidance regarding the type of research needed to validate that a purported “new form” of creatine is a bioavailable, effective and safe source of creatine for dietary supplements. Based on this analysis, we categorized forms of creatine that are being sold as dietary supplements as either having strong, some, or no evidence of bioavailability and safety. As will be seen, CrM continues to be the only source of creatine that has substantial evidence to support bioavailability, efficacy, and safety. Additionally, CrM is the source of creatine recommended explicitly by professional societies and organizations and approved for use in global markets as a dietary ingredient or food additive.
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Affiliation(s)
- Richard B. Kreider
- Exercise & Sport Nutrition Lab, Human Clinical Research Facility, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843, USA
- Correspondence: ; Tel.: +1-972-458-1498
| | - Ralf Jäger
- Increnovo LLC, Milwaukee, WI 53202, USA; (R.J.); (M.P.)
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9
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Effects of Creatine Supplementation on Brain Function and Health. Nutrients 2022; 14:nu14050921. [PMID: 35267907 PMCID: PMC8912287 DOI: 10.3390/nu14050921] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 02/06/2023] Open
Abstract
While the vast majority of research involving creatine supplementation has focused on skeletal muscle, there is a small body of accumulating research that has focused on creatine and the brain. Preliminary studies indicate that creatine supplementation (and guanidinoacetic acid; GAA) has the ability to increase brain creatine content in humans. Furthermore, creatine has shown some promise for attenuating symptoms of concussion, mild traumatic brain injury and depression but its effect on neurodegenerative diseases appears to be lacking. The purpose of this narrative review is to summarize the current body of research pertaining to creatine supplementation on total creatine and phophorylcreatine (PCr) content, explore GAA as an alternative or adjunct to creatine supplementation on brain creatine uptake, assess the impact of creatine on cognition with a focus on sleep deprivation, discuss the effects of creatine supplementation on a variety of neurological and mental health conditions, and outline recent advances on creatine supplementation as a neuroprotective supplement following traumatic brain injury or concussion.
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10
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Burke LM. Nutritional approaches to counter performance constraints in high-level sports competition. Exp Physiol 2021; 106:2304-2323. [PMID: 34762329 PMCID: PMC9299184 DOI: 10.1113/ep088188] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 11/03/2021] [Indexed: 12/12/2022]
Abstract
New Findings What is the topic of this review? The nutritional strategies that athletes use during competition events to optimize performance and the reasons they use them. What advances does it highlight? A range of nutritional strategies can be used by competitive athletes, alone or in combination, to address various event‐specific factors that constrain event performance. Evidence for such practices is constantly evolving but must be combined with understanding of the complexities of real‐life sport for optimal implementation.
Abstract High‐performance athletes share a common goal despite the unique nature of their sport: to pace or manage their performance to achieve the highest sustainable outputs over the duration of the event. Periodic or sustained decline in the optimal performance of event tasks, involves an interplay between central and peripheral phenomena that can often be reduced or delayed in onset by nutritional strategies. Contemporary nutrition practices undertaken before, during or between events include strategies to ensure the availability of limited muscle fuel stores. This includes creatine supplementation to increase muscle phosphocreatine content and consideration of the type, amount and timing of dietary carbohydrate intake to optimize muscle and liver glycogen stores or to provide additional exogenous substrate. Although there is interest in ketogenic low‐carbohydrate high‐fat diets and exogenous ketone supplements to provide alternative fuels to spare muscle carbohydrate use, present evidence suggests a limited utility of these strategies. Mouth sensing of a range of food tastants (e.g., carbohydrate, quinine, menthol, caffeine, fluid, acetic acid) may provide a central nervous system derived boost to sports performance. Finally, despite decades of research on hypohydration and exercise capacity, there is still contention around their effect on sports performance and the best guidance around hydration for sporting events. A unifying model proposes that some scenarios require personalized fluid plans while others might be managed by an ad hoc approach (ad libitum or thirst‐driven drinking) to fluid intake.
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Affiliation(s)
- Louise M Burke
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
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11
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Timing of Creatine Supplementation around Exercise: A Real Concern? Nutrients 2021; 13:nu13082844. [PMID: 34445003 PMCID: PMC8401986 DOI: 10.3390/nu13082844] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 08/09/2021] [Accepted: 08/10/2021] [Indexed: 01/21/2023] Open
Abstract
Creatine has been considered an effective ergogenic aid for several decades; it can help athletes engaged in a variety of sports and obtain performance gains. Creatine supplementation increases muscle creatine stores; several factors have been identified that may modify the intramuscular increase and subsequent performance benefits, including baseline muscle Cr content, type II muscle fibre content and size, habitual dietary intake of Cr, aging, and exercise. Timing of creatine supplementation in relation to exercise has recently been proposed as an important consideration to optimise muscle loading and performance gains, although current consensus is lacking regarding the ideal ingestion time. Research has shifted towards comparing creatine supplementation strategies pre-, during-, or post-exercise. Emerging evidence suggests greater benefits when creatine is consumed after exercise compared to pre-exercise, although methodological limitations currently preclude solid conclusions. Furthermore, physiological and mechanistic data are lacking, in regard to claims that the timing of creatine supplementation around exercise moderates gains in muscle creatine and exercise performance. This review discusses novel scientific evidence on the timing of creatine intake, the possible mechanisms that may be involved, and whether the timing of creatine supplementation around exercise is truly a real concern.
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Abstract
ABSTRACT Creatine is a popular and widely used ergogenic dietary supplement among athletes, for which studies have consistently shown increased lean muscle mass and exercise capacity when used with short-duration, high-intensity exercise. In addition to strength gains, research has shown that creatine supplementation may provide additional benefits including enhanced postexercise recovery, injury prevention, rehabilitation, as well as a number of potential neurologic benefits that may be relevant to sports. Studies show that short- and long-term supplementation is safe and well tolerated in healthy individuals and in a number of patient populations.
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Affiliation(s)
- Matthew Hall
- Sports Medicine, UConn Primary Care Sports Medicine Fellowship, Department of Orthopedics, UConn Health, Farmington, CT
| | - Elizabeth Manetta
- Department of Family Medicine, University of Connecticut, St. Francis Hospital, Hartford, CT
| | - Kristofer Tupper
- Department of Family Medicine, University of Connecticut, St. Francis Hospital, Hartford, CT
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13
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Wax B, Kerksick CM, Jagim AR, Mayo JJ, Lyons BC, Kreider RB. Creatine for Exercise and Sports Performance, with Recovery Considerations for Healthy Populations. Nutrients 2021; 13:1915. [PMID: 34199588 PMCID: PMC8228369 DOI: 10.3390/nu13061915] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/27/2021] [Accepted: 05/30/2021] [Indexed: 02/06/2023] Open
Abstract
Creatine is one of the most studied and popular ergogenic aids for athletes and recreational weightlifters seeking to improve sport and exercise performance, augment exercise training adaptations, and mitigate recovery time. Studies consistently reveal that creatine supplementation exerts positive ergogenic effects on single and multiple bouts of short-duration, high-intensity exercise activities, in addition to potentiating exercise training adaptations. In this respect, supplementation consistently demonstrates the ability to enlarge the pool of intracellular creatine, leading to an amplification of the cell's ability to resynthesize adenosine triphosphate. This intracellular expansion is associated with several performance outcomes, including increases in maximal strength (low-speed strength), maximal work output, power production (high-speed strength), sprint performance, and fat-free mass. Additionally, creatine supplementation may speed up recovery time between bouts of intense exercise by mitigating muscle damage and promoting the faster recovery of lost force-production potential. Conversely, contradictory findings exist in the literature regarding the potential ergogenic benefits of creatine during intermittent and continuous endurance-type exercise, as well as in those athletic tasks where an increase in body mass may hinder enhanced performance. The purpose of this review was to summarize the existing literature surrounding the efficacy of creatine supplementation on exercise and sports performance, along with recovery factors in healthy populations.
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Affiliation(s)
- Benjamin Wax
- Applied Physiology Laboratory, Department of Kinesiology, Mississippi State University, Mississippi State, MS 39759, USA
| | - Chad M. Kerksick
- Exercise & Performance Nutrition Laboratory, College of Science, Technology, and Health, Lindenwood University, St. Charles, MO 63301, USA
| | - Andrew R. Jagim
- Sports Medicine, Mayo Clinic Health System, La Crosse, WI 54601, USA;
| | - Jerry J. Mayo
- Department of Nutrition and Family Sciences, University of Central Arkansas, Conway, AR 72035, USA;
| | - Brian C. Lyons
- Health, Kinesiology, and Sport Management Department, University of Wisconsin—Parkside, Kenosha, WI 53141, USA;
| | - Richard B. Kreider
- Exercise & Sport Nutrition Lab, Human Clinical Research Facility, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843, USA;
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14
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Creatine Supplementation in Women's Health: A Lifespan Perspective. Nutrients 2021; 13:nu13030877. [PMID: 33800439 PMCID: PMC7998865 DOI: 10.3390/nu13030877] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/01/2021] [Accepted: 03/05/2021] [Indexed: 12/14/2022] Open
Abstract
Despite extensive research on creatine, evidence for use among females is understudied. Creatine characteristics vary between males and females, with females exhibiting 70–80% lower endogenous creatine stores compared to males. Understanding creatine metabolism pre- and post-menopause yields important implications for creatine supplementation for performance and health among females. Due to the hormone-related changes to creatine kinetics and phosphocreatine resynthesis, supplementation may be particularly important during menses, pregnancy, post-partum, during and post-menopause. Creatine supplementation among pre-menopausal females appears to be effective for improving strength and exercise performance. Post-menopausal females may also experience benefits in skeletal muscle size and function when consuming high doses of creatine (0.3 g·kg−1·d−1); and favorable effects on bone when combined with resistance training. Pre-clinical and clinical evidence indicates positive effects from creatine supplementation on mood and cognition, possibly by restoring brain energy levels and homeostasis. Creatine supplementation may be even more effective for females by supporting a pro-energetic environment in the brain. The purpose of this review was to highlight the use of creatine in females across the lifespan with particular emphasis on performance, body composition, mood, and dosing strategies.
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Antonio J, Candow DG, Forbes SC, Gualano B, Jagim AR, Kreider RB, Rawson ES, Smith-Ryan AE, VanDusseldorp TA, Willoughby DS, Ziegenfuss TN. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show? J Int Soc Sports Nutr 2021; 18:13. [PMID: 33557850 PMCID: PMC7871530 DOI: 10.1186/s12970-021-00412-w] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/28/2021] [Indexed: 01/01/2023] Open
Abstract
Supplementing with creatine is very popular amongst athletes and exercising individuals for improving muscle mass, performance and recovery. Accumulating evidence also suggests that creatine supplementation produces a variety of beneficial effects in older and patient populations. Furthermore, evidence-based research shows that creatine supplementation is relatively well tolerated, especially at recommended dosages (i.e. 3-5 g/day or 0.1 g/kg of body mass/day). Although there are over 500 peer-refereed publications involving creatine supplementation, it is somewhat surprising that questions regarding the efficacy and safety of creatine still remain. These include, but are not limited to: 1. Does creatine lead to water retention? 2. Is creatine an anabolic steroid? 3. Does creatine cause kidney damage/renal dysfunction? 4. Does creatine cause hair loss / baldness? 5. Does creatine lead to dehydration and muscle cramping? 6. Is creatine harmful for children and adolescents? 7. Does creatine increase fat mass? 8. Is a creatine 'loading-phase' required? 9. Is creatine beneficial for older adults? 10. Is creatine only useful for resistance / power type activities? 11. Is creatine only effective for males? 12. Are other forms of creatine similar or superior to monohydrate and is creatine stable in solutions/beverages? To answer these questions, an internationally renowned team of research experts was formed to perform an evidence-based scientific evaluation of the literature regarding creatine supplementation.
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Affiliation(s)
- Jose Antonio
- Department of Health and Human Performance, Nova Southeastern University, Davie, Florida, USA.
| | - Darren G Candow
- Faculty of Kinesiology and Health Studies, University of Regina, Regina, Canada
| | - Scott C Forbes
- Department of Physical Education, Faculty of Education, Brandon University, Brandon, MB, Canada
| | - Bruno Gualano
- Applied Physiology & Nutrition Research Group; School of Medicine, FMUSP, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Andrew R Jagim
- Sports Medicine Department, Mayo Clinic Health System, La Crosse, WI, USA
| | - Richard B Kreider
- Exercise & Sport Nutrition Lab, Human Clinical Research Facility, Department of Health & Kinesiology, Texas A&M University, College Station, USA
| | - Eric S Rawson
- Department of Health, Nutrition, and Exercise Science, Messiah University, Mechanicsburg, PA, USA
| | - Abbie E Smith-Ryan
- Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, NC, USA
| | - Trisha A VanDusseldorp
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, GA, USA
| | - Darryn S Willoughby
- School of Exercise and Sport Science, University of Mary Hardin-Baylor, Belton, TX, USA
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16
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Kreider RB, Stout JR. Creatine in Health and Disease. Nutrients 2021; 13:nu13020447. [PMID: 33572884 PMCID: PMC7910963 DOI: 10.3390/nu13020447] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/22/2021] [Accepted: 01/27/2021] [Indexed: 12/14/2022] Open
Abstract
Although creatine has been mostly studied as an ergogenic aid for exercise, training, and sport, several health and potential therapeutic benefits have been reported. This is because creatine plays a critical role in cellular metabolism, particularly during metabolically stressed states, and limitations in the ability to transport and/or store creatine can impair metabolism. Moreover, increasing availability of creatine in tissue may enhance cellular metabolism and thereby lessen the severity of injury and/or disease conditions, particularly when oxygen availability is compromised. This systematic review assesses the peer-reviewed scientific and medical evidence related to creatine's role in promoting general health as we age and how creatine supplementation has been used as a nutritional strategy to help individuals recover from injury and/or manage chronic disease. Additionally, it provides reasonable conclusions about the role of creatine on health and disease based on current scientific evidence. Based on this analysis, it can be concluded that creatine supplementation has several health and therapeutic benefits throughout the lifespan.
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Affiliation(s)
- Richard B. Kreider
- Human Clinical Research Facility, Exercise & Sport Nutrition Lab, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843, USA
- Correspondence:
| | - Jeffery R. Stout
- Physiology of Work and Exercise Response (POWER) Laboratory, Institute of Exercise Physiology and Rehabilitation Science, School of Kinesiology and Physical Therapy, University of Central Florida, 12494 University Blvd., Orlando, FL 32816, USA;
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17
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Gnoni A, Longo S, Gnoni GV, Giudetti AM. Carnitine in Human Muscle Bioenergetics: Can Carnitine Supplementation Improve Physical Exercise? Molecules 2020; 25:E182. [PMID: 31906370 PMCID: PMC6982879 DOI: 10.3390/molecules25010182] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 12/27/2019] [Accepted: 12/31/2019] [Indexed: 12/18/2022] Open
Abstract
l-Carnitine is an amino acid derivative widely known for its involvement in the transport of long-chain fatty acids into the mitochondrial matrix, where fatty acid oxidation occurs. Moreover, l-Carnitine protects the cell from acyl-CoA accretion through the generation of acylcarnitines. Circulating carnitine is mainly supplied by animal-based food products and to a lesser extent by endogenous biosynthesis in the liver and kidney. Human muscle contains high amounts of carnitine but it depends on the uptake of this compound from the bloodstream, due to muscle inability to synthesize carnitine. Mitochondrial fatty acid oxidation represents an important energy source for muscle metabolism particularly during physical exercise. However, especially during high-intensity exercise, this process seems to be limited by the mitochondrial availability of free l-carnitine. Hence, fatty acid oxidation rapidly declines, increasing exercise intensity from moderate to high. Considering the important role of fatty acids in muscle bioenergetics, and the limiting effect of free carnitine in fatty acid oxidation during endurance exercise, l-carnitine supplementation has been hypothesized to improve exercise performance. So far, the question of the role of l-carnitine supplementation on muscle performance has not definitively been clarified. Differences in exercise intensity, training or conditioning of the subjects, amount of l-carnitine administered, route and timing of administration relative to the exercise led to different experimental results. In this review, we will describe the role of l-carnitine in muscle energetics and the main causes that led to conflicting data on the use of l-carnitine as a supplement.
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Affiliation(s)
- Antonio Gnoni
- Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari “Aldo Moro”, 70124 Bari, Italy;
| | - Serena Longo
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy; (S.L.); (G.V.G.)
| | - Gabriele V. Gnoni
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy; (S.L.); (G.V.G.)
| | - Anna M. Giudetti
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy; (S.L.); (G.V.G.)
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18
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Sports Foods and Dietary Supplements for Optimal Function and Performance Enhancement in Track-and-Field Athletes. Int J Sport Nutr Exerc Metab 2019; 29:198-209. [PMID: 30299192 DOI: 10.1123/ijsnem.2018-0271] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Athletes are exposed to numerous nutritional products, attractively marketed with claims of optimizing health, function, and performance. However, there is limited evidence to support many of these claims, and the efficacy and safety of many products is questionable. The variety of nutritional aids considered for use by track-and-field athletes includes sports foods, performance supplements, and therapeutic nutritional aids. Support for sports foods and five evidence-based performance supplements (caffeine, creatine, nitrate/beetroot juice, β-alanine, and bicarbonate) varies according to the event, the specific scenario of use, and the individual athlete's goals and responsiveness. Specific challenges include developing protocols to manage repeated use of performance supplements in multievent or heat-final competitions or the interaction between several products which are used concurrently. Potential disadvantages of supplement use include expense, false expectancy, and the risk of ingesting banned substances sometimes present as contaminants. However, a pragmatic approach to the decision-making process for supplement use is recommended. The authors conclude that it is pertinent for sports foods and nutritional supplements to be considered only where a strong evidence base supports their use as safe, legal, and effective and that such supplements are trialed thoroughly by the individual before committing to use in a competition setting.
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Avgerinos KI, Spyrou N, Bougioukas KI, Kapogiannis D. Effects of creatine supplementation on cognitive function of healthy individuals: A systematic review of randomized controlled trials. Exp Gerontol 2018; 108:166-173. [PMID: 29704637 DOI: 10.1016/j.exger.2018.04.013] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 04/03/2018] [Accepted: 04/18/2018] [Indexed: 10/17/2022]
Abstract
BACKGROUND AND AIMS Creatine is a supplement used by sportsmen to increase athletic performance by improving energy supply to muscle tissues. It is also an essential brain compound and some hypothesize that it aids cognition by improving energy supply and neuroprotection. The aim of this systematic review is to investigate the effects of oral creatine administration on cognitive function in healthy individuals. METHODS A search of multiple electronic databases was performed for the identification of randomized clinical trials (RCTs) examining the cognitive effects of oral creatine supplementation in healthy individuals. RESULTS Six studies (281 individuals) met our inclusion criteria. Generally, there was evidence that short term memory and intelligence/reasoning may be improved by creatine administration. Regarding other cognitive domains, such as long-term memory, spatial memory, memory scanning, attention, executive function, response inhibition, word fluency, reaction time and mental fatigue, the results were conflicting. Performance on cognitive tasks stayed unchanged in young individuals. Vegetarians responded better than meat-eaters in memory tasks but for other cognitive domains no differences were observed. CONCLUSIONS Oral creatine administration may improve short-term memory and intelligence/reasoning of healthy individuals but its effect on other cognitive domains remains unclear. Findings suggest potential benefit for aging and stressed individuals. Since creatine is safe, future studies should include larger sample sizes. It is imperative that creatine should be tested on patients with dementias or cognitive impairment.
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Affiliation(s)
- Konstantinos I Avgerinos
- 251 Hellenic Airforce General Hospital, Athens, Greece; Aristotle University of Thessaloniki, Faculty of Health Sciences, Department of Medicine, Greece.
| | - Nikolaos Spyrou
- 251 Hellenic Airforce General Hospital, Athens, Greece; Faculty of Medicine, National and Kapodistrian University of Athens, Greece
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20
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Maughan RJ, Burke LM, Dvorak J, Larson-Meyer DE, Peeling P, Phillips SM, Rawson ES, Walsh NP, Garthe I, Geyer H, Meeusen R, van Loon LJC, Shirreffs SM, Spriet LL, Stuart M, Vernec A, Currell K, Ali VM, Budgett RG, Ljungqvist A, Mountjoy M, Pitsiladis YP, Soligard T, Erdener U, Engebretsen L. IOC consensus statement: dietary supplements and the high-performance athlete. Br J Sports Med 2018; 52:439-455. [PMID: 29540367 PMCID: PMC5867441 DOI: 10.1136/bjsports-2018-099027] [Citation(s) in RCA: 337] [Impact Index Per Article: 56.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2018] [Indexed: 12/24/2022]
Abstract
Nutrition usually makes a small but potentially valuable contribution to successful performance in elite athletes, and dietary supplements can make a minor contribution to this nutrition programme. Nonetheless, supplement use is widespread at all levels of sport. Products described as supplements target different issues, including (1) the management of micronutrient deficiencies, (2) supply of convenient forms of energy and macronutrients, and (3) provision of direct benefits to performance or (4) indirect benefits such as supporting intense training regimens. The appropriate use of some supplements can benefit the athlete, but others may harm the athlete's health, performance, and/or livelihood and reputation (if an antidoping rule violation results). A complete nutritional assessment should be undertaken before decisions regarding supplement use are made. Supplements claiming to directly or indirectly enhance performance are typically the largest group of products marketed to athletes, but only a few (including caffeine, creatine, specific buffering agents and nitrate) have good evidence of benefits. However, responses are affected by the scenario of use and may vary widely between individuals because of factors that include genetics, the microbiome and habitual diet. Supplements intended to enhance performance should be thoroughly trialled in training or simulated competition before being used in competition. Inadvertent ingestion of substances prohibited under the antidoping codes that govern elite sport is a known risk of taking some supplements. Protection of the athlete's health and awareness of the potential for harm must be paramount; expert professional opinion and assistance is strongly advised before an athlete embarks on supplement use.
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Affiliation(s)
| | - Louise M Burke
- Sports Nutrition, Australian Institute of Sport, Canberra, Australia
- Mary MacKillop Institute for Health Research, Melbourne, Australia
| | - Jiri Dvorak
- Department of Neurology, Schulthess Clinic, Zurich, Switzerland
| | - D Enette Larson-Meyer
- Department of Family & Consumer Sciences (Human Nutrition), University of Wyoming, Laramie, Wyoming, USA
| | - Peter Peeling
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Crawley, Western Australia, Australia
- Western Australian Institute of Sport, Mount Claremont, Australia
| | | | - Eric S Rawson
- Department of Health, Nutrition, and Exercise Science, Messiah College, Mechanicsburg, Pennsylvania, USA
| | - Neil P Walsh
- College of Health and Behavioural Sciences, Bangor University, Bangor, UK
| | - Ina Garthe
- The Norwegian Olympic and Paralympic Committee and Confederation of Sport, Oslo, Norway
| | - Hans Geyer
- Institute of Biochemistry, Center for Preventive Doping Research, German Sport University, Cologne, Germany
| | - Romain Meeusen
- Human Physiology Research Group, Vrije Universiteit Brussel, Brussel, Belgium
| | - Lucas J C van Loon
- Mary MacKillop Institute for Health Research, Melbourne, Australia
- Department of Human Biology and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
| | | | - Lawrence L Spriet
- Human Health & Nutritional Sciences, University of Guelph, Ontario, Canada
| | | | - Alan Vernec
- Department of Science and Medicine, World Anti-Doping Agency (WADA), Montreal, Canada
| | | | - Vidya M Ali
- Medical and Scientific Commission, International Olympic Committee, Lausanne, Switzerland
| | - Richard Gm Budgett
- Medical and Scientific Department, International Olympic Committee, Lausanne, Switzerland
| | | | - Margo Mountjoy
- Human Health and Nutritional Sciences, Health and Performance, Centre University of Guelph, Guelph, Ontario, Canada
- Medical and Scientific Commission Games Group, International Olympic Committee, Lausanne, Switzerland
| | - Yannis P Pitsiladis
- Medical and Scientific Commission, International Olympic Committee, Lausanne, Switzerland
| | - Torbjørn Soligard
- Medical and Scientific Department, International Olympic Committee, Lausanne, Switzerland
| | - Uğur Erdener
- Medical and Scientific Commission, International Olympic Committee, Lausanne, Switzerland
| | - Lars Engebretsen
- Medical and Scientific Department, International Olympic Committee, Lausanne, Switzerland
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21
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IOC Consensus Statement: Dietary Supplements and the High-Performance Athlete. Int J Sport Nutr Exerc Metab 2018; 28:104-125. [PMID: 29589768 DOI: 10.1123/ijsnem.2018-0020] [Citation(s) in RCA: 270] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Nutrition usually makes a small but potentially valuable contribution to successful performance in elite athletes, and dietary supplements can make a minor contribution to this nutrition program. Nonetheless, supplement use is widespread at all levels of sport. Products described as supplements target different issues, including the management of micronutrient deficiencies, supply of convenient forms of energy and macronutrients, and provision of direct benefits to performance or indirect benefits such as supporting intense training regimens. The appropriate use of some supplements can offer benefits to the athlete, but others may be harmful to the athlete's health, performance, and/or livelihood and reputation if an anti-doping rule violation results. A complete nutritional assessment should be undertaken before decisions regarding supplement use are made. Supplements claiming to directly or indirectly enhance performance are typically the largest group of products marketed to athletes, but only a few (including caffeine, creatine, specific buffering agents and nitrate) have good evidence of benefits. However, responses are affected by the scenario of use and may vary widely between individuals because of factors that include genetics, the microbiome, and habitual diet. Supplements intended to enhance performance should be thoroughly trialed in training or simulated competition before implementation in competition. Inadvertent ingestion of substances prohibited under the anti-doping codes that govern elite sport is a known risk of taking some supplements. Protection of the athlete's health and awareness of the potential for harm must be paramount, and expert professional opinion and assistance is strongly advised before embarking on supplement use.
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22
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Abstract
A strong foundation in physical conditioning and sport-specific experience, in addition to a bespoke and periodized training and nutrition program, are essential for athlete development. Once these underpinning factors are accounted for, and the athlete reaches a training maturity and competition level where marginal gains determine success, a role may exist for the use of evidence-based performance supplements. However, it is important that any decisions surrounding performance supplements are made in consideration of robust information that suggests the use of a product is safe, legal, and effective. The following review focuses on the current evidence-base for a number of common (and emerging) performance supplements used in sport. The supplements discussed here are separated into three categories based on the level of evidence supporting their use for enhancing sports performance: (1) established (caffeine, creatine, nitrate, beta-alanine, bicarbonate); (2) equivocal (citrate, phosphate, carnitine); and (3) developing. Within each section, the relevant performance type, the potential mechanisms of action, and the most common protocols used in the supplement dosing schedule are summarized.
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23
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Abstract
Fat and carbohydrate are the major fuel sources utilised for oxidative, mitochondrial ATP resynthesis during human skeletal muscle contraction. The relative contribution of these two substrates to ATP resynthesis and total energy expenditure during exercise can vary substantially, and is predominantly determined by fuel availability and exercise intensity and duration. For example, the increased ATP demand that occurs with an increase in exercise intensity is met by increases in both fat and carbohydrate oxidation up to an intensity of approximately 60-70 % of maximal oxygen consumption. When exercise intensity increases beyond this workload, skeletal muscle carbohydrate utilisation is accelerated, which results in a reduction and inhibition of the relative and absolute contribution of fat oxidation to total energy expenditure. However, the precise mechanisms regulating muscle fuel selection and underpinning the decline in fat oxidation remain unclear. This brief review will primarily address the theory that a carbohydrate flux-mediated reduction in the availability of muscle carnitine to the mitochondrial enzyme carnitine palmitoyltransferase 1, a rate-limiting step in mitochondrial fat translocation, is a key mechanism for the decline in fat oxidation during high-intensity exercise. This is discussed in relation to recent work in this area investigating fuel metabolism at various exercise intensities and taking advantage of the discovery that skeletal muscle carnitine content can be nutritionally increased in vivo in human subjects.
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24
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Kreider RB, Kalman DS, Antonio J, Ziegenfuss TN, Wildman R, Collins R, Candow DG, Kleiner SM, Almada AL, Lopez HL. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr 2017; 14:18. [PMID: 28615996 PMCID: PMC5469049 DOI: 10.1186/s12970-017-0173-z] [Citation(s) in RCA: 333] [Impact Index Per Article: 47.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 05/30/2017] [Indexed: 12/16/2022] Open
Abstract
Creatine is one of the most popular nutritional ergogenic aids for athletes. Studies have consistently shown that creatine supplementation increases intramuscular creatine concentrations which may help explain the observed improvements in high intensity exercise performance leading to greater training adaptations. In addition to athletic and exercise improvement, research has shown that creatine supplementation may enhance post-exercise recovery, injury prevention, thermoregulation, rehabilitation, and concussion and/or spinal cord neuroprotection. Additionally, a number of clinical applications of creatine supplementation have been studied involving neurodegenerative diseases (e.g., muscular dystrophy, Parkinson's, Huntington's disease), diabetes, osteoarthritis, fibromyalgia, aging, brain and heart ischemia, adolescent depression, and pregnancy. These studies provide a large body of evidence that creatine can not only improve exercise performance, but can play a role in preventing and/or reducing the severity of injury, enhancing rehabilitation from injuries, and helping athletes tolerate heavy training loads. Additionally, researchers have identified a number of potentially beneficial clinical uses of creatine supplementation. These studies show that short and long-term supplementation (up to 30 g/day for 5 years) is safe and well-tolerated in healthy individuals and in a number of patient populations ranging from infants to the elderly. Moreover, significant health benefits may be provided by ensuring habitual low dietary creatine ingestion (e.g., 3 g/day) throughout the lifespan. The purpose of this review is to provide an update to the current literature regarding the role and safety of creatine supplementation in exercise, sport, and medicine and to update the position stand of International Society of Sports Nutrition (ISSN).
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Affiliation(s)
- Richard B. Kreider
- Exercise & Sport Nutrition Lab, Human Clinical Research Facility, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843-4243 USA
| | - Douglas S. Kalman
- Nutrition Research Unit, QPS, 6141 Sunset Drive Suite 301, Miami, FL 33143 USA
| | - Jose Antonio
- Department of Health and Human Performance, Nova Southeastern University, Davie, FL 33328 USA
| | - Tim N. Ziegenfuss
- The Center for Applied Health Sciences, 4302 Allen Road, STE 120, Stow, OH 44224 USA
| | - Robert Wildman
- Post Active Nutrition, 111 Leslie St, Dallas, TX 75208 USA
| | - Rick Collins
- Collins Gann McCloskey & Barry, PLLC, 138 Mineola Blvd., Mineola, NY 11501 USA
| | - Darren G. Candow
- Faculty of Kinesiology and Health Studies, University of Regina, Regina, SK S4S 0A2 Canada
| | | | | | - Hector L. Lopez
- The Center for Applied Health Sciences, 4302 Allen Road, STE 120, Stow, OH 44224 USA
- Supplement Safety Solutions, LLC, Bedford, MA 01730 USA
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25
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Oliveira CC, Ferreira D, Caetano C, Granja D, Pinto R, Mendes B, Sousa M. Nutrition and Supplementation in Soccer. Sports (Basel) 2017; 5:sports5020028. [PMID: 29910389 PMCID: PMC5968974 DOI: 10.3390/sports5020028] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 04/25/2017] [Accepted: 05/03/2017] [Indexed: 12/26/2022] Open
Abstract
Contemporary elite soccer features increased physical demands during match-play, as well as a larger number of matches per season. Now more than ever, aspects related to performance optimization are highly regarded by both players and soccer coaches. Here, nutrition takes a special role as most elite teams try to provide an adequate diet to guarantee maximum performance while ensuring a faster recovery from matches and training exertions. It is currently known that manipulation and periodization of macronutrients, as well as sound hydration practices, have the potential to interfere with training adaptation and recovery. A careful monitoring of micronutrient status is also relevant to prevent undue fatigue and immune impairment secondary to a deficiency status. Furthermore, the sensible use of evidence-based dietary supplements may also play a role in soccer performance optimization. In this sense, several nutritional recommendations have been issued. This detailed and comprehensive review addresses the most relevant and up-to-date nutritional recommendations for elite soccer players, covering from macro and micronutrients to hydration and selected supplements in different contexts (daily requirements, pre, peri and post training/match and competition).
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Affiliation(s)
- César Chaves Oliveira
- Instituto Politécnico de Viana do Castelo - Escola Superior de Desporto e Lazer, Viana do Castelo 4960-320, Portugal.
| | - Diogo Ferreira
- Benfica LAB, Sport Lisboa e Benfica, Lisbon 1500-313, Portugal.
| | - Carlos Caetano
- Benfica LAB, Sport Lisboa e Benfica, Lisbon 1500-313, Portugal.
| | - Diana Granja
- Benfica LAB, Sport Lisboa e Benfica, Lisbon 1500-313, Portugal.
| | - Ricardo Pinto
- Benfica LAB, Sport Lisboa e Benfica, Lisbon 1500-313, Portugal.
| | - Bruno Mendes
- Benfica LAB, Sport Lisboa e Benfica, Lisbon 1500-313, Portugal.
| | - Mónica Sousa
- Instituto Politécnico de Leiria - Escola Superior de Saúde, Leiria 2411-901, Portugal.
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26
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Yáñez-Silva A, Buzzachera CF, Piçarro IDC, Januario RSB, Ferreira LHB, McAnulty SR, Utter AC, Souza-Junior TP. Effect of low dose, short-term creatine supplementation on muscle power output in elite youth soccer players. J Int Soc Sports Nutr 2017; 14:5. [PMID: 28190980 PMCID: PMC5296953 DOI: 10.1186/s12970-017-0162-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 02/01/2017] [Indexed: 12/25/2022] Open
Abstract
Background To determine the effects of a low dose, short-term Creatine monohydrate (Cr) supplementation (0.03 g.kg.d−1 during 14 d) on muscle power output in elite youth soccer players. Methods Using a two-group matched, double blind, placebo-controlled design, nineteen male soccer players (mean age = 17.0 ± 0.5 years) were randomly assigned to either Cr (N = 9) or placebo (N = 10) group. Before and after supplementation, participants performed a 30s Wingate Anaerobic Test (WAnT) to assess peak power output (PPO), mean power output (MPO), fatigue index (FI), and total work. Results There were significant increases in both PPO and MPO after the Cr supplementation period (P ≤ 0.05) but not the placebo period. There were also significant increases in total work, but not FI, after the Cr supplementation and placebo periods (P ≤ 0.05). Notably, there were differences in total work between the Cr and placebo groups after (P ≤ 0.05) but not before the 14 d supplementation period. Conclusion There is substantial evidence to indicate that a low-dose, short-term oral Cr supplementation beneficially affected muscle power output in elite youth soccer players.
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Affiliation(s)
- Aquiles Yáñez-Silva
- Dirección de Investigación, Universidad Mayor Santiago de Chile; Universidad Santo Tomás, Talca. Chile. Carrera de Educación Física, Santiago de Chile, Chile
| | - Cosme F Buzzachera
- Department of Physical Education, North University of Parana, Londrina, Brazil
| | - Ivan Da C Piçarro
- School of Physical Education, Max Planck Faculty, Indaiatuba, Brazil
| | - Renata S B Januario
- Department of Physical Education, North University of Parana, Londrina, Brazil
| | - Luis H B Ferreira
- Department of Physical Education, Research Group on Metabolism, Nutrition and Strength Training, Curitiba, Brazil
| | - Steven R McAnulty
- Department of Health and Exercise Science, Appalachian State University, Boone, USA
| | - Alan C Utter
- Department of Health and Exercise Science, Appalachian State University, Boone, USA
| | - Tacito P Souza-Junior
- Department of Physical Education, Research Group on Metabolism, Nutrition and Strength Training, Curitiba, Brazil.,Department of Health and Exercise Science, Appalachian State University, Boone, USA
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27
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The effect of combined supplementation of carbohydrates and creatine on anaerobic performance. Biol Sport 2017; 34:169-175. [PMID: 28566811 PMCID: PMC5424457 DOI: 10.5114/biolsport.2017.65336] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 01/18/2016] [Accepted: 11/29/2016] [Indexed: 11/17/2022] Open
Abstract
The purpose of the study was to examine the effect of creatine (Cr) supplementation on anaerobic performance when ingesting creatine and carbohydrates (CHO) together. Twenty male physical education students comprised the two experimental (CR and CRCHO) and one control (CON) groups of the study. All groups performed three 30 s anaerobic Wingate tests (AWTs) interspersed with 6 minutes of recovery. The CR group (n = 7) ingested 5 g of Cr 5 times per day for 4 days. Subjects in the CRCHO group (n = 6) ingested the same quantity but additionally after each 5 g dose of Cr consumed 500 ml of a commercially available energy drink containing 100 g of simple sugars. Over all three AWTs average mean power improved significantly compared to baseline for the CR group (5.51%) but not for the CRCHO group (3.06%). Mean power for the second AWT was improved following the acute loading for the CR group only (4.54%) and for the third AWT for both CR (8.49%) and CRCHO (5.75%) groups. Over all three AWTs a significant change was recorded in average peak power following the acute loading for the CR group (8.26%) but not for the CRCHO group (4.11%). Peak power was significantly improved following the loading only for the CR group during the third AWT (19.79%). No changes in AWT performance were recorded for the CON group after intervention. The findings of the present study suggest that ingesting creatine together with carbohydrates will not further improve performance compared to the ingestion of creatine only.
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Naderi A, de Oliveira EP, Ziegenfuss TN, Willems MT. Timing, Optimal Dose and Intake Duration of Dietary Supplements with Evidence-Based Use in Sports Nutrition. J Exerc Nutrition Biochem 2016; 20:1-12. [PMID: 28150472 PMCID: PMC5545206 DOI: 10.20463/jenb.2016.0031] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
[Purpose] The aim of the present narrative review was to consider the evidence on the timing, optimal dose and intake duration of the main dietary supplements in sports nutrition, i.e. β-alanine, nitrate, caffeine, creatine, sodium bicarbonate, carbohydrate and protein. [Methods] This review article focuses on timing, optimal dose and intake duration of main dietary supplements in sports nutrition. [Results] This paper reviewed the evidence to determine the optimal time, efficacy doses and intake duration for sports supplements verified by scientific evidence that report a performance enhancing effect in both situation of laboratory and training settings. [Conclusion] Consumption of the supplements are usually suggested into 5 specific times, such as pre-exercise (nitrate, caffeine, sodium bicarbonate, carbohydrate and protein), during exercise (carbohydrate), post-exercise (creatine, carbohydrate, protein), meal time (β-alanine, creatine, sodium bicarbonate, nitrate, carbohydrate and protein), and before sleep (protein). In addition, the recommended dosing protocol for the supplements nitrate and β-alanine are fixed amounts irrespective of body weight, while dosing protocol for sodium bicarbonate, caffeine and creatine supplements are related to corrected body weight (mg/kg bw). Also, intake duration is suggested for creatine and β-alanine, being effective in chronic daily time < 2 weeks while caffeine, sodium bicarbonate are effective in acute daily time (1-3 hours). Plus, ingestion of nitrate supplement is required in both chronic daily time < 28 days and acute daily time (2- 2.5 h) prior exercise.
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Affiliation(s)
- Alireza Naderi
- Department of Sport Physiology, Boroujerd Branch, Islamic Azad University, Boroujerd, Iran
| | - Erick P de Oliveira
- School of Medicine, Federal University of Uberlandia, Uberlandia, Minas Gerais State, Brazil
| | | | - MarkE T Willems
- Department of Sport and Exercise Sciences, University of Chichester, College Lane, Chichester, United Kingdom
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Tomcik KA, Smiles WJ, Camera DM, Hügel HM, Hawley JA, Watts R. Fenugreek increases insulin-stimulated creatine content in L6C11 muscle myotubes. Eur J Nutr 2016; 56:973-979. [PMID: 26732502 DOI: 10.1007/s00394-015-1145-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 12/17/2015] [Indexed: 11/28/2022]
Abstract
PURPOSE Creatine uptake by muscle cells is increased in the presence of insulin. Accordingly, compounds with insulin-like actions may also augment creatine uptake. The aim of this study was to investigate whether Trigonella foenum-graecum (fenugreek), an insulin mimetic, increases total intracellular creatine levels in vitro. METHODS Total cellular creatine content was measured fluorometrically in L6C11 muscle myotubes treated for 1, 4, and 24 h with 0.5 mM creatine (CR), CR and 20 μg/mL fenugreek seed extract (CR + FEN), CR and 100 nM insulin (CR + INS), and CR + INS + FEN (n = 6 per treatment group). Alterations in the expression of the sodium- and chloride-dependent creatine transporter, SLC6A8, and key signaling proteins in the PI3-K/Akt pathway were determined. RESULTS Compared to control (CON), CR + INS + FEN increased total creatine content after 4 h (P < 0.05), whereas all conditions increased SLC6A8 protein expression above CON at this time (P < 0.05). Changes in insulin signaling were demonstrated via increases in AktThr308 phosphorylation, with CR + INS > CON and CR at 1 h (P < 0.05) and with CR + INS + FEN > CON, CR, and CR + INS at 4 h (P < 0.05). In contrast, no changes in PKCζ/λ or GLUT4 phosphorylation were detected. CONCLUSION Fenugreek, when combined with insulin, modulates creatine content via a mechanism which is independent of the activity of SLC6A8, suggesting that an alternative mechanism is responsible for the regulation and facilitation of insulin-mediated creatine uptake in skeletal muscle cells.
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Affiliation(s)
- Kristyen A Tomcik
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, 3065, Australia
| | - William J Smiles
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, 3065, Australia
| | - Donny M Camera
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, 3065, Australia
| | - Helmut M Hügel
- School of Applied Sciences and Health Innovations Research Institute, RMIT University, Melbourne, VIC, Australia
| | - John A Hawley
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, 3065, Australia. .,Research Institute for Sports and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.
| | - Rani Watts
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, 3065, Australia
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Shannon CE, Nixon AV, Greenhaff PL, Stephens FB. Protein ingestion acutely inhibits insulin-stimulated muscle carnitine uptake in healthy young men. Am J Clin Nutr 2016; 103:276-82. [PMID: 26675771 PMCID: PMC4756606 DOI: 10.3945/ajcn.115.119826] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 10/26/2015] [Indexed: 10/22/2022] Open
Abstract
BACKGROUND Increasing skeletal muscle carnitine content represents an appealing intervention in conditions of perturbed lipid metabolism such as obesity and type 2 diabetes but requires chronic L-carnitine feeding on a daily basis in a high-carbohydrate beverage. OBJECTIVE We investigated whether whey protein ingestion could reduce the carbohydrate load required to stimulate insulin-mediated muscle carnitine accretion. DESIGN Seven healthy men [mean ± SD age: 24 ± 5 y; body mass index (in kg/m(2)): 23 ± 3] ingested 80 g carbohydrate, 40 g carbohydrate + 40 g protein, or control (flavored water) beverages 60 min after the ingestion of 4.5 g L-carnitine tartrate (3 g L-carnitine; 0.1% (2)[H]3-L-carnitine). Serum insulin concentration, net forearm carnitine balance (NCB; arterialized-venous and venous plasma carnitine difference × brachial artery flow), and carnitine disappearance (Rd) and appearance (Ra) rates were determined at 20-min intervals for 180 min. RESULTS Serum insulin and plasma flow areas under the curve (AUCs) were similarly elevated by carbohydrate [4.5 ± 0.8 U/L · min (P < 0.01) and 0.5 ± 0.6 L (P < 0.05), respectively] and carbohydrate+protein [3.8 ± 0.6 U/L · min (P < 0.01) and 0.4 ± 0.6 L (P = 0.05), respectively] consumption, respectively, compared with the control visit (0.04 ± 0.1 U/L · min and -0.5 ± 0.2 L). Plasma carnitine AUC was greater after carbohydrate+protein consumption (3.5 ± 0.5 mmol/L · min) than after control and carbohydrate visits [2.1 ± 0.2 mmol/L · min (P < 0.05) and 1.9 ± 0.3 mmol/L · min (P < 0.01), respectively]. NCB AUC with carbohydrate (4.1 ± 3.1 μmol) was greater than during control and carbohydrate-protein visits (-8.6 ± 3.0 and -14.6 ± 6.4 μmol, respectively; P < 0.05), as was Rd AUC after carbohydrate (35.7 ± 25.2 μmol) compared with control and carbohydrate consumption [19.7 ± 15.5 μmol (P = 0.07) and 14.8 ± 9.6 μmol (P < 0.05), respectively]. CONCLUSIONS The insulin-mediated increase in forearm carnitine balance with carbohydrate consumption was acutely blunted by a carbohydrate+protein beverage, which suggests that carbohydrate+protein could inhibit chronic muscle carnitine accumulation.
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Affiliation(s)
- Chris E Shannon
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, United Kingdom
| | - Aline V Nixon
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, United Kingdom
| | - Paul L Greenhaff
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, United Kingdom
| | - Francis B Stephens
- Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham, United Kingdom
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The Effects of Hyperhydrating Supplements Containing Creatine and Glucose on Plasma Lipids and Insulin Sensitivity in Endurance-Trained Athletes. JOURNAL OF AMINO ACIDS 2015; 2015:352458. [PMID: 26167296 PMCID: PMC4488253 DOI: 10.1155/2015/352458] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 05/18/2015] [Accepted: 05/19/2015] [Indexed: 11/28/2022]
Abstract
The addition of carbohydrate (CHO) in the form of simple sugars to creatine (Cr) supplements is central. The study aimed to determine whether ingestion of glucose (Glu) simultaneously with Cr and glycerol (Cr/Gly) supplement is detrimental to plasma lipids of endurance-trained individuals and find out whether modification arising can be attenuated by replacing part of the Glu with alpha lipoic acid (Ala). Twenty-two endurance-trained cyclists were randomized to receive Cr/Gly/Glu (11.4 g Cr-H2O, 1 g Gly/kg BM, and 150 g Glu) or Cr/Gly/Glu/Ala (11.4 g Cr-H2O, 1 g Gly/kg BM, 100 g Glu, and 1 g Ala) for 7 days. Fasting concentration of TAG increased significantly (P < 0.01) after supplementation with Cr/Gly/Glu (before: 0.9 ± 0.2 mmol/L; after: 1.3 ± 0.4 mmol/L) and Cr/Gly/Glu/Ala (before: 0.8 ± 0.2 mmol/L; after: 1.2 ± 0.5 mmol/L) but changes were not different between the groups. Supplementation significantly (P < 0.05) increased the TAG to HDL-cholesterol ratio but had no effect on fasting concentration of total, HDL-, and LDL-cholesterol and insulin resistance. Thus, addition of Glu to Cr containing supplements enhances plasma TAG concentration and the TAG to HDL-cholesterol ratio and this enhancement cannot be attenuated by partial replacement of Glu with Ala.
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Smith RN, Agharkar AS, Gonzales EB. A review of creatine supplementation in age-related diseases: more than a supplement for athletes. F1000Res 2014; 3:222. [PMID: 25664170 PMCID: PMC4304302 DOI: 10.12688/f1000research.5218.1] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/10/2014] [Indexed: 12/12/2022] Open
Abstract
Creatine is an endogenous compound synthesized from arginine, glycine and methionine. This dietary supplement can be acquired from food sources such as meat and fish, along with athlete supplement powders. Since the majority of creatine is stored in skeletal muscle, dietary creatine supplementation has traditionally been important for athletes and bodybuilders to increase the power, strength, and mass of the skeletal muscle. However, new uses for creatine have emerged suggesting that it may be important in preventing or delaying the onset of neurodegenerative diseases associated with aging. On average, 30% of muscle mass is lost by age 80, while muscular weakness remains a vital cause for loss of independence in the elderly population. In light of these new roles of creatine, the dietary supplement's usage has been studied to determine its efficacy in treating congestive heart failure, gyrate atrophy, insulin insensitivity, cancer, and high cholesterol. In relation to the brain, creatine has been shown to have antioxidant properties, reduce mental fatigue, protect the brain from neurotoxicity, and improve facets/components of neurological disorders like depression and bipolar disorder. The combination of these benefits has made creatine a leading candidate in the fight against age-related diseases, such as Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, long-term memory impairments associated with the progression of Alzheimer's disease, and stroke. In this review, we explore the normal mechanisms by which creatine is produced and its necessary physiology, while paying special attention to the importance of creatine supplementation in improving diseases and disorders associated with brain aging and outlining the clinical trials involving creatine to treat these diseases.
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Affiliation(s)
- Rachel N. Smith
- Department of Pharmacology & Neuroscience, UNT Health Science Center, Fort Worth, TX, TX, 76107, USA
| | - Amruta S. Agharkar
- Department of Pharmacology & Neuroscience, UNT Health Science Center, Fort Worth, TX, TX, 76107, USA
| | - Eric B. Gonzales
- Department of Pharmacology & Neuroscience, UNT Health Science Center, Fort Worth, TX, TX, 76107, USA
- Institute for Aging and Alzheimer’s Disease Research, UNT Health Science Center, Fort Worth, TX, TX, 76107, USA
- Cardiovascular Research Institute, UNT Health Science Center, Fort Worth, TX, TX, 76107, USA
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Oliver JM, Jagim AR, Pischel I, Jäger R, Purpura M, Sanchez A, Fluckey J, Riechman S, Greenwood M, Kelly K, Meininger C, Rasmussen C, Kreider RB. Effects of short-term ingestion of Russian Tarragon prior to creatine monohydrate supplementation on whole body and muscle creatine retention and anaerobic sprint capacity: a preliminary investigation. J Int Soc Sports Nutr 2014; 11:6. [PMID: 24568653 PMCID: PMC3975968 DOI: 10.1186/1550-2783-11-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 02/19/2014] [Indexed: 11/28/2022] Open
Abstract
Background Extracts of Russian Tarragon (RT) have been reported to produce anti-hyperglycemic effects and influence plasma creatine (Cr) levels while supplementing with creatine monohydrate (CrM). The purpose of this preliminary study was to determine if short-term, low-dose aqueous RT extract ingestion prior to CrM supplementation influences whole body Cr retention, muscle Cr or measures of anaerobic sprint performance. Methods In a double-blind, randomized, and crossover manner; 10 recreationally trained males (20 ± 2 yrs; 179 ± 9 cm; 91.3 ± 34 kg) ingested 500 mg of aqueous RT extract (Finzelberg, Andernach, Germany) or 500 mg placebo 30-minutes prior to ingesting 5 g of CrM (Creapure®, AlzChem AG, Germany) twice per day for 5-days then repeated after a 6-week wash-out period. Urine was collected at baseline and during each of the 5-days of supplementation to determine urine Cr content. Whole body Cr retention was estimated from urine samples. Muscle biopsies were obtained for determination of muscle free Cr content. Participants also performed two 30-second Wingate anaerobic capacity tests prior to and following supplementation for determination of peak power (PP), mean power (MP), and total work (TW). Data were analysed by repeated measures MANOVA. Results Whole body daily Cr retention increased in both groups following supplementation (0.0 ± 0.0; 8.2 ± 1.4, 6.5 ± 2.4, 5.6 ± 3.2, 6.1 ± 2.6, 4.8 ± 3.2 g · d-1; p = 0.001) with no differences observed between groups (p = 0.59). After 3 and 5-days of supplementation, respectively, both supplementation protocols demonstrated a significant increase in muscle free Cr content from baseline (4.8 ± 16.7, 15.5 ± 23.6 mmol · kg-1 DW, p = 0.01) with no significant differences observed between groups (p = 0.34). Absolute change in MP (9 ± 57, 35 ± 57 W; p = 0.031), percent change in MP (2.5 ± 10.5, 6.7 ± 10.4%; p = 0.026), absolute change in TW (275 ± 1,700, 1,031 ± 1,721 J; p = 0.032), and percent change in TW (2.5 ± 10.5, 6.6 ± 10.4%; p = 0.027) increased over time in both groups with no differences observed between groups. Conclusions Short-term CrM supplementation (10 g · d-1 for 5-days) significantly increased whole body Cr retention and muscle free Cr content. However, ingesting 500 mg of RT 30-min prior to CrM supplementation did not affect whole body Cr retention, muscle free Cr content, or anaerobic sprint capacity in comparison to ingesting CrM with a placebo.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Richard B Kreider
- Department of Health and Kinesiology, Exercise and Sport Nutrition Lab, Texas A&M University, College Station, TX 77843-4243, USA.
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Hageböck M, Stahl U, Bader J. Stability of creatine derivatives during simulated digestion in an in vitro model. Food Funct 2013; 5:359-63. [PMID: 24366174 DOI: 10.1039/c3fo60453e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Newly developed forms of creatine are often claimed to exhibit improved bioavailability and efficacy. They are of great interest for sports nutrition and therapeutic uses. However, for most newer creatine forms stability after ingestion under physiological conditions is insufficiently documented, relevant data are inconsistent or even missing. Therefore, we developed a controlled simulated digestion system for testing different creatine derivatives in specific simulated parts of the human digestive system. All derivatives showed high stability with negligible formation of creatinine.
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Affiliation(s)
- Martin Hageböck
- Research and Teaching Institute for Brewing in Berlin, Seestraße 13, 13353 Berlin, Germany.
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STEGEN SANNE, BLANCQUAERT LAURA, EVERAERT INGE, BEX TINE, TAES YOURI, CALDERS PATRICK, ACHTEN ERIC, DERAVE WIM. Meal and Beta-Alanine Coingestion Enhances Muscle Carnosine Loading. Med Sci Sports Exerc 2013; 45:1478-85. [DOI: 10.1249/mss.0b013e31828ab073] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Jagim AR, Oliver JM, Sanchez A, Galvan E, Fluckey J, Riechman S, Greenwood M, Kelly K, Meininger C, Rasmussen C, Kreider RB. A buffered form of creatine does not promote greater changes in muscle creatine content, body composition, or training adaptations than creatine monohydrate. J Int Soc Sports Nutr 2012; 9:43. [PMID: 22971354 PMCID: PMC3479057 DOI: 10.1186/1550-2783-9-43] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 09/06/2012] [Indexed: 11/16/2022] Open
Abstract
Background Creatine monohydrate (CrM) has been consistently reported to increase muscle creatine content and improve high-intensity exercise capacity. However, a number of different forms of creatine have been purported to be more efficacious than CrM. The purpose of this study was to determine if a buffered creatine monohydrate (KA) that has been purported to promote greater creatine retention and training adaptations with fewer side effects at lower doses is more efficacious than CrM supplementation in resistance-trained individuals. Methods In a double-blind manner, 36 resistance-trained participants (20.2 ± 2 years, 181 ± 7 cm, 82.1 ± 12 kg, and 14.7 ± 5% body fat) were randomly assigned to supplement their diet with CrM (Creapure® AlzChem AG, Trostberg, Germany) at normal loading (4 x 5 g/d for 7-days) and maintenance (5 g/d for 21-days) doses; KA (Kre-Alkalyn®, All American Pharmaceutical, Billings, MT, USA) at manufacturer’s recommended doses (KA-L, 1.5 g/d for 28-days); or, KA with equivalent loading (4 x 5 g/d for 7-days) and maintenance (5 g/d) doses of CrM (KA-H). Participants were asked to maintain their current training programs and record all workouts. Muscle biopsies from the vastus lateralis, fasting blood samples, body weight, DEXA determined body composition, and Wingate Anaerobic Capacity (WAC) tests were performed at 0, 7, and 28-days while 1RM strength tests were performed at 0 and 28-days. Data were analyzed by a repeated measures multivariate analysis of variance (MANOVA) and are presented as mean ± SD changes from baseline after 7 and 28-days, respectively. Results Muscle free creatine content obtained in a subgroup of 25 participants increased in all groups over time (1.4 ± 20.7 and 11.9 ± 24.0 mmol/kg DW, p = 0.03) after 7 and 28-days, respectively, with no significant differences among groups (KA-L −7.9 ± 22.3, 4.7 ± 27.0; KA-H 1.0 ± 12.8, 9.1 ± 23.2; CrM 11.3 ± 23.9, 22.3 ± 21.0 mmol/kg DW, p = 0.46). However, while no overall group differences were observed (p = 0.14), pairwise comparison between the KA-L and CrM groups revealed that changes in muscle creatine content tended to be greater in the CrM group (KA-L −1.1 ± 4.3, CrM 11.2 ± 4.3 mmol/kg DW, p = 0.053 [mean ± SEM]). Although some significant time effects were observed, no significant group x time interactions (p > 0.05) were observed in changes in body mass, fat free mass, fat mass, percent body fat, or total body water; bench press and leg press 1RM strength; WAC mean power, peak power, or total work; serum blood lipids, markers of catabolism and bone status, and serum electrolyte status; or, whole blood makers of lymphocytes and red cells. Serum creatinine levels increased in all groups (p < 0.001) with higher doses of creatine promoting greater increases in serum creatinine (p = 0.03) but the increases observed (0.1 – 0.2 mg/dl) were well within normal values for active individuals (i.e., <1.28 ± 0.2 mg/dl). Serum LDL was decreased to a greater degree following ingesting loading doses in the CrM group but returned to baseline during the maintenance phase. No side effects were reported. Conclusions Neither manufacturers recommended doses of KA (1.5 g/d) or KA with equivalent loading (20 g/d for 7-days) and maintenance doses (5 g/d for 21-days) of CrM promoted greater changes in muscle creatine content, body composition, strength, or anaerobic capacity than CrM (20 g/d for 7-days, 5 g/d for 21-days). There was no evidence that supplementing the diet with a buffered form of creatine resulted in fewer side effects than CrM. These findings do not support claims that consuming a buffered form of creatine is a more efficacious and/or safer form of creatine to consume than creatine monohydrate.
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Affiliation(s)
- Andrew R Jagim
- Department of Health and Kinesiology, Exercise and Sport Nutrition Laboratory, Texas A&M University, College Station, TX 77843-4243, USA
| | - Jonathan M Oliver
- Department of Health and Kinesiology, Exercise and Sport Nutrition Laboratory, Texas A&M University, College Station, TX 77843-4243, USA.,Department of Sports Medicine and Nutrition, Neuromuscular Research Laboratory, University of Pittsburgh, Pittsburgh, PA, 15203, Oakland
| | - Adam Sanchez
- Department of Health and Kinesiology, Exercise and Sport Nutrition Laboratory, Texas A&M University, College Station, TX 77843-4243, USA
| | - Elfego Galvan
- Department of Health and Kinesiology, Exercise and Sport Nutrition Laboratory, Texas A&M University, College Station, TX 77843-4243, USA
| | - James Fluckey
- Department of Health and Kinesiology, Muscle Biology Laboratory, Texas A&M University, College Station, TX 77843-4243, USA
| | - Steven Riechman
- Department of Health and Kinesiology, Human Countermeasures Laboratory, Texas A&M University, College Station, TX 77843-4243, USA
| | - Michael Greenwood
- Department of Health and Kinesiology, Exercise and Sport Nutrition Laboratory, Texas A&M University, College Station, TX 77843-4243, USA
| | - Katherine Kelly
- Department of Systems Biology and Translational Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, USA
| | - Cynthia Meininger
- Department of Systems Biology and Translational Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, USA
| | - Christopher Rasmussen
- Department of Health and Kinesiology, Exercise and Sport Nutrition Laboratory, Texas A&M University, College Station, TX 77843-4243, USA
| | - Richard B Kreider
- Department of Health and Kinesiology, Exercise and Sport Nutrition Laboratory, Texas A&M University, College Station, TX 77843-4243, USA
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Cooper R, Naclerio F, Allgrove J, Jimenez A. Creatine supplementation with specific view to exercise/sports performance: an update. J Int Soc Sports Nutr 2012; 9:33. [PMID: 22817979 PMCID: PMC3407788 DOI: 10.1186/1550-2783-9-33] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 07/20/2012] [Indexed: 11/23/2022] Open
Abstract
Creatine is one of the most popular and widely researched natural supplements. The majority of studies have focused on the effects of creatine monohydrate on performance and health; however, many other forms of creatine exist and are commercially available in the sports nutrition/supplement market. Regardless of the form, supplementation with creatine has regularly shown to increase strength, fat free mass, and muscle morphology with concurrent heavy resistance training more than resistance training alone. Creatine may be of benefit in other modes of exercise such as high-intensity sprints or endurance training. However, it appears that the effects of creatine diminish as the length of time spent exercising increases. Even though not all individuals respond similarly to creatine supplementation, it is generally accepted that its supplementation increases creatine storage and promotes a faster regeneration of adenosine triphosphate between high intensity exercises. These improved outcomes will increase performance and promote greater training adaptations. More recent research suggests that creatine supplementation in amounts of 0.1 g/kg of body weight combined with resistance training improves training adaptations at a cellular and sub-cellular level. Finally, although presently ingesting creatine as an oral supplement is considered safe and ethical, the perception of safety cannot be guaranteed, especially when administered for long period of time to different populations (athletes, sedentary, patient, active, young or elderly).
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Affiliation(s)
- Robert Cooper
- Centre for Sports Science and Human Performance, School of Science, University of Greenwich at Medway, Central Avenue, Chatham Maritime, Kent, ME4 4TB, United Kingdom.
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Beis LY, Polyviou T, Malkova D, Pitsiladis YP. The effects of creatine and glycerol hyperhydration on running economy in well trained endurance runners. J Int Soc Sports Nutr 2011; 8:24. [PMID: 22176668 PMCID: PMC3283512 DOI: 10.1186/1550-2783-8-24] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 12/16/2011] [Indexed: 11/16/2022] Open
Abstract
Background Ingestion of creatine (Cr) and glycerol (Gly) has been reported to be an effective method in expanding water compartments within the human body, attenuating the rise in heart rate (HR) and core temperature (Tcore) during exercise in the heat. Despite these positive effects, a substantial water retention could potentially impair endurance performance through increasing body mass (BM) and consequently impacting negatively on running economy (RE). The objective of the present study was to investigate the effects of a combined Cr and Gly supplementation on thermoregulatory and cardiovascular responses and RE during running for 30 min at speed corresponding to 60% of maximal oxygen uptake (V˙O2max) in hot and cool conditions. Methods Cr·H2O (11.4 g), Gly (1 g·kg-1 BM) and Glucose polymer (75 g) were administered twice daily to 15 male endurance runners during a 7-day period. Exercise trials were conducted pre- and post-supplementation at 10 and 35°C and 70% relative humidity. Results BM and total body water increased by 0.90 ± 0.40 kg (P < 0.01; mean ± SD) and 0.71 ± 0.42 L (P < 0.01), respectively following supplementation. Despite the significant increase in BM, supplementation had no effect on V˙O2 and therefore RE. Both HR and Tcore were attenuated significantly after supplementation (P < 0.05, for both). Nevertheless, thermal comfort and rating of perceived exertion was not significantly different between pre- and post-supplementation. Similarly, no significant differences were found in sweat loss, serum osmolality, blood lactate and in plasma volume changes between pre- and post-supplementation. Conclusions Combining Cr and Gly is effective in reducing thermal and cardiovascular strain during exercise in the heat without negatively impacting on RE.
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Affiliation(s)
- Lukas Y Beis
- College of Medicine, Veterinary and Life Sciences, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK.
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Leland KM, McDonald TL, Drescher KM. Effect of creatine, creatinine, and creatine ethyl ester on TLR expression in macrophages. Int Immunopharmacol 2011; 11:1341-7. [PMID: 21575742 DOI: 10.1016/j.intimp.2011.04.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 04/27/2011] [Accepted: 04/28/2011] [Indexed: 11/18/2022]
Abstract
Despite the widespread availability and use of dietary supplements, minimal work has been performed to assess the potential dangers many of these supplements may have on the host's well-being, in particular the host's ability to respond to infection. One supplement extensively used by both adolescents and adults is creatine. Using Real-time PCR, we examined the impact of short-term exposure of a mouse macrophage cell line (RAW 264.7 cells) to two readily available forms of creatine used in supplements--creatine monohydrate (CR) and creatine ethyl ester (CEE) as well as the end product of creatine metabolism, creatinine (CRN), on expression of toll-like receptor-2 (TLR-2), TLR-3, TLR-4, and TLR-7. CR down-regulated TLR-2, TLR-3, TLR-4 and TLR-7 mRNA levels in RAW cells. Similar results were observed following exposure of RAW cells to CRN. Conversely CEE appears to possess immunostimulatory properties and increases expression of TLR-2, TLR-3, TLR-4, and TLR-7 in RAW cells. These data are supported by immunostaining using antibodies specific for the individual TLRs before and after exposure of RAW cells to CR, CRN, or CEE. To extend these findings, we isolated murine splenocytes and exposed the cells to CR, CEE, or CRN for 24 hours and performed immunofluorescent staining for TLR-2, TLR-3, TLR-4 and TLR-7. The results obtained from this study with primary splenocytes were consistent with the studies using RAW cells. Together, these data suggest that creatine and creatine derivatives may impact the ability of immune cells to sense a wide array of viral and bacterial pathogens. Of great interest, CRN--largely considered to be a waste product of the argenine biosynthesis pathway may also have immunosuppressive properties similar to those of CR.
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Affiliation(s)
- Korey M Leland
- Department of Medical Microbiology and Immunology, Creighton University Medical School, Omaha, Nebraska, USA.
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Low-dose creatine supplementation enhances fatigue resistance in the absence of weight gain. Nutrition 2011; 27:451-5. [DOI: 10.1016/j.nut.2010.04.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 04/07/2010] [Accepted: 04/07/2010] [Indexed: 11/20/2022]
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Jäger R, Purpura M, Shao A, Inoue T, Kreider RB. Analysis of the efficacy, safety, and regulatory status of novel forms of creatine. Amino Acids 2011; 40:1369-83. [PMID: 21424716 PMCID: PMC3080578 DOI: 10.1007/s00726-011-0874-6] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Accepted: 11/30/2010] [Indexed: 11/28/2022]
Abstract
Creatine has become one of the most popular dietary supplements in the sports nutrition market. The form of creatine that has been most extensively studied and commonly used in dietary supplements is creatine monohydrate (CM). Studies have consistently indicated that CM supplementation increases muscle creatine and phosphocreatine concentrations by approximately 15–40%, enhances anaerobic exercise capacity, and increases training volume leading to greater gains in strength, power, and muscle mass. A number of potential therapeutic benefits have also been suggested in various clinical populations. Studies have indicated that CM is not degraded during normal digestion and that nearly 99% of orally ingested CM is either taken up by muscle or excreted in urine. Further, no medically significant side effects have been reported in literature. Nevertheless, supplement manufacturers have continually introduced newer forms of creatine into the marketplace. These newer forms have been purported to have better physical and chemical properties, bioavailability, efficacy, and/or safety profiles than CM. However, there is little to no evidence that any of the newer forms of creatine are more effective and/or safer than CM whether ingested alone and/or in combination with other nutrients. In addition, whereas the safety, efficacy, and regulatory status of CM is clearly defined in almost all global markets; the safety, efficacy, and regulatory status of other forms of creatine present in today’s marketplace as a dietary or food supplement is less clear.
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Affiliation(s)
- Ralf Jäger
- Increnovo LLC, 2138 E Lafayette Pl., Milwaukee, WI 53202, USA
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Abstract
A well designed diet is the foundation upon which optimal training and performance can be developed. However, as long as competitive sports have existed, athletes have attempted to improve their performance by ingesting a variety of substances. This practice has given rise to a multi-billion-dollar industry that aggressively markets its products as performance enhancing, often without objective, scientific evidence to support such claims. While a number of excellent reviews have evaluated the performance-enhancing effects of most dietary supplements, less attention has been paid to the performance-enhancing claims of dietary supplements in the context of team-sport performance. Dietary supplements that enhance some types of athletic performance may not necessarily enhance team-sport performance (and vice versa). Thus, the first aim of this review is to critically evaluate the ergogenic value of the most common dietary supplements used by team-sport athletes. The term dietary supplements will be used in this review and is defined as any product taken by the mouth, in addition to common foods, that has been proposed to have a performance-enhancing effect; this review will only discuss substances that are not currently banned by the World Anti-Doping Agency. Evidence is emerging to support the performance-enhancing claims of some, but not all, dietary supplements that have been proposed to improve team-sport-related performance. For example, there is good evidence that caffeine can improve single-sprint performance, while caffeine, creatine and sodium bicarbonate ingestion have all been demonstrated to improve multiple-sprint performance. The evidence is not so strong for the performance-enhancing benefits of β-alanine or colostrum. Current evidence does not support the ingestion of ribose, branched-chain amino acids or β-hydroxy-β-methylbutyrate, especially in well trained athletes. More research on the performance-enhancing effects of the dietary supplements highlighted in this review needs to be conducted using team-sport athletes and using team-sport-relevant testing (e.g. single- and multiple-sprint performance). It should also be considered that there is no guarantee that dietary supplements that improve isolated performance (i.e. single-sprint or jump performance) will remain effective in the context of a team-sport match. Thus, more research is also required to investigate the effects of dietary supplements on simulated or actual team-sport performance. A second aim of this review was to investigate any health issues associated with the ingestion of the more commonly promoted dietary supplements. While most of the supplements described in the review appear safe when using the recommended dose, the effects of higher doses (as often taken by athletes) on indices of health remain unknown, and further research is warranted. Finally, anecdotal reports suggest that team-sport athletes often ingest more than one dietary supplement and very little is known about the potential adverse effects of ingesting multiple supplements. Supplements that have been demonstrated to be safe and efficacious when ingested on their own may have adverse effects when combined with other supplements. More research is required to investigate the effects of ingesting multiple supplements (both on performance and health).
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Affiliation(s)
- David Bishop
- Institute of Sport, Exercise and Active Living (ISEAL) and School of Sport and Exercise Science, Victoria University, Melbourne, Victoria, Australia.
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Pittas G, Hazell MD, Simpson EJ, Greenhaff PL. Optimization of insulin-mediated creatine retention during creatine feeding in humans. J Sports Sci 2010; 28:67-74. [DOI: 10.1080/02640410903390071] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Sale C, Harris RC, Florance J, Kumps A, Sanvura R, Poortmans JR. Urinary creatine and methylamine excretion following 4 × 5 g · day−1or 20 × 1 g · day−1of creatine monohydrate for 5 days. J Sports Sci 2009; 27:759-66. [DOI: 10.1080/02640410902838237] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Singh S, Dash AK. Chapter 1 creatine monohydrate. PROFILES OF DRUG SUBSTANCES, EXCIPIENTS, AND RELATED METHODOLOGY 2009; 34:1-35. [PMID: 22469171 DOI: 10.1016/s1871-5125(09)34001-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Rawson ES, Lieberman HR, Walsh TM, Zuber SM, Harhart JM, Matthews TC. Creatine supplementation does not improve cognitive function in young adults. Physiol Behav 2008; 95:130-4. [DOI: 10.1016/j.physbeh.2008.05.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Revised: 05/06/2008] [Accepted: 05/07/2008] [Indexed: 11/25/2022]
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CRIBB PAULJ, WILLIAMS ANDREWD, HAYES ALAN. A Creatine-Protein-Carbohydrate Supplement Enhances Responses to Resistance Training. Med Sci Sports Exerc 2007; 39:1960-8. [DOI: 10.1249/mss.0b013e31814fb52a] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Buford TW, Kreider RB, Stout JR, Greenwood M, Campbell B, Spano M, Ziegenfuss T, Lopez H, Landis J, Antonio J. International Society of Sports Nutrition position stand: creatine supplementation and exercise. J Int Soc Sports Nutr 2007; 4:6. [PMID: 17908288 PMCID: PMC2048496 DOI: 10.1186/1550-2783-4-6] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Accepted: 08/30/2007] [Indexed: 11/10/2022] Open
Affiliation(s)
- Thomas W Buford
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Richard B Kreider
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Jeffrey R Stout
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Mike Greenwood
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Bill Campbell
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Marie Spano
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Tim Ziegenfuss
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Hector Lopez
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Jamie Landis
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Jose Antonio
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
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Baker-Fulco CJ, Fulco CS, Kellogg MD, Glickman E, Young AJ. Voluntary Muscle Function after Creatine Supplementation in Acute Hypobaric Hypoxia. Med Sci Sports Exerc 2006; 38:1418-24. [PMID: 16888454 DOI: 10.1249/01.mss.0000228948.70399.38] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE To determine whether creatine (Cr) supplementation improves muscle performance during exposure to acute hypobaric hypoxia. METHODS Seven healthy men (28 +/- 6 yr, mean +/- SD) performed submaximal intermittent static knee contractions interspersed with maximal voluntary contractions (MVCs) every minute to exhaustion (approximately 50% of rested MVC force) in normoxia and hypobaric hypoxia (separated by 3 d) after supplementation with Cr (20 g.d(-1) for 7 d then 5 g.d(-1) for 4-7 d) or placebo (Pla) in a double-blind, randomized crossover study. A 5-wk period without supplementation separated treatments. Each test day, subjects performed two bouts (separated by 2 min) at their preset submaximal force, 32 +/- 4% rested MVC). RESULTS Rested MVC force (860 +/- 66 N) and MVC force at exhaustion (396 +/- 27 N; 47 +/- 3% rested MVC) did not differ among treatments or environments (P > 0.05). For bout 1, endurance time was shorter in hypobaria (26 +/- 3 min) than normoxia (34 +/- 2 min) (P < 0.01), but did not differ between Cr (27 +/- 3 min) and Pla (33 +/- 3 min) (P > 0.05). MVC force returned to similar levels (P >0.05) in bout 2 after recovery in all four sessions (to approximately 615 N). For bout 2, endurance time also was shorter in hypobaria (7 +/- 1 min) than normoxia (9 +/- 1 min) (P < 0.03) but did not differ between Cr and Pla (P > 0.05). CONCLUSION This study, which used an exercise model designed to impose the same target contraction force under all experimental conditions, found no effect of Cr on maximal force, muscle endurance, or recovery in normoxia or hypobaric hypoxia.
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Affiliation(s)
- Carol J Baker-Fulco
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760-5007, USA.
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