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Pashayee-Khamene F, Heidari Z, Asbaghi O, Ashtary-Larky D, Goudarzi K, Forbes SC, Candow DG, Bagheri R, Ghanavati M, Dutheil F. Creatine supplementation protocols with or without training interventions on body composition: a GRADE-assessed systematic review and dose-response meta-analysis. J Int Soc Sports Nutr 2024; 21:2380058. [PMID: 39042054 PMCID: PMC11268231 DOI: 10.1080/15502783.2024.2380058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 07/02/2024] [Indexed: 07/24/2024] Open
Abstract
BACKGROUND Despite the robust evidence demonstrating positive effects from creatine supplementation (primarily when associated with resistance training) on measures of body composition, there is a lack of a comprehensive evaluation regarding the influence of creatine protocol parameters (including dose and form) on body mass and estimates of fat-free and fat mass. METHODS Randomized controlled trials (RCTs) evaluating the effect of creatine supplementation on body composition were included. Electronic databases, including PubMed, Web of Science, and Scopus were searched up to July 2023. Heterogeneity tests were performed. Random effect models were assessed based on the heterogeneity tests, and pooled data were examined to determine the weighted mean difference (WMD) with a 95% confidence interval (CI). RESULTS From 4831 initial records, a total of 143 studies met the inclusion criteria. Creatine supplementation increased body mass (WMD: 0.86 kg; 95% CI: 0.76 to 0.96, I2 = 0%) and fat-free mass (WMD: 0.82 kg; 95% CI: 0.57 to 1.06, I2 = 0%) while reducing body fat percentage (WMD: -0.28 %; 95% CI: -0.47 to -0.09; I2 = 0%). Studies that incorporated a maintenance dose of creatine or performed resistance training in conjunction with supplementation had greater effects on body composition. CONCLUSION Creatine supplementation has a small effect on body mass and estimates of fat-free mass and body fat percentage. These findings were more robust when combined with resistance training.
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Affiliation(s)
| | - Zeinab Heidari
- Ahvaz Jundishapur University of Medical Sciences, Student research committee, Ahvaz, Iran
| | - Omid Asbaghi
- Shahid Beheshti University of Medical Sciences, Cancer Research Center, Tehran, Iran
| | - Damoon Ashtary-Larky
- Ahvaz Jundishapur University of Medical Sciences, Nutrition and Metabolic Diseases Research Center, Ahvaz, Iran
| | - Kian Goudarzi
- Shahid Beheshti University of Medical Sciences, Faculty of Medicine, Tehran, Iran
| | - Scott C Forbes
- Brandon University, Department of Physical Education Studies, Brandon, MB, Canada
| | - Darren G. Candow
- University of Regina, Faculty of Kinesiology and Health Studies, Regina, SK, Canada
| | - Reza Bagheri
- University of Isfahan, Department of Exercise Physiology, Isfahan, Iran
| | - Matin Ghanavati
- Shahid Beheshti University of Medical Sciences, National Nutrition and Food Technology Research Institute, (Faculty of Nutrition Science and Food Technology), Tehran, Iran
| | - Fred Dutheil
- University Hospital of Clermont–Ferrand, Université Clermont Auvergne, CNRS, LaPSCo, Physiological and Psychosocial Stress, CHU Clermont–Ferrand, Occupational and Environmental Medicine, Clermont–Ferrand, France
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Moore SR, Gordon AN, Cabre HE, Hackney AC, Smith-Ryan AE. A Randomized Controlled Trial of Changes in Fluid Distribution across Menstrual Phases with Creatine Supplementation. Nutrients 2023; 15:nu15020429. [PMID: 36678300 PMCID: PMC9865497 DOI: 10.3390/nu15020429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/10/2023] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
This study examined the effects of creatine (Cr) loading on body mass (BM) and fluid markers of total body water (TBW), extra-cellular fluid (ECF), and intra-cellular fluid (ICF) across the menstrual cycle (MC). Thirty moderately active females, either naturally-menstruating (NM) or using hormonal contraceptives (HC), were randomized to Cr (Cr; 4 × 5 g/day of creatine monohydrate for 5 days; n = 15) or a non-caloric placebo (PL; n = 15) using a double-blind, placebo-controlled design, with a menstrual phase crossover. BM, TBW, ECF, and ICF were measured at pre- and post-supplementation in randomized order of follicular phase (FP; NM: MC days 0−8, HC: inactive pill days) or luteal phase (LP; NM: ≤15 days from next projected cycle start date, HC: active pill days) using bioelectrical impedance spectroscopy. Acute hydration status and salivary estrogen were used as covariates. Change in BM was not different between groups across MC ([PL-Cr] Δ 0.40 ± 0.50 kg; p = 0.427) or between MC phase across groups ([FP-LP] Δ 0.31 ± 0.48 kg; p = 0.528). TBW (p = 0.802), ECF (p = 0.373), and ICF (p = 0.795) were not different between supplement groups at pre-supplementation/FP time points. There were no significant differences between the NM and HC subjects at any time point, for any outcome (p > 0.05). Following LP supplementation, significant changes were observed in TBW (Cr: Δ 0.83 ± 0.38 L, PL: Δ −0.62 ± 0.38 L; p = 0.021), ECF (Cr: Δ 0.46 ± 0.15 L, PL: Δ −0.19 ± 0.15 L; p = 0.013), and ICF (Cr: Δ 0.74 ± 0.23 L, PL: Δ −0.02 ± 0.23 L; p = 0.041). These data demonstrate an increase in all fluid compartments in the LP following Cr loading, without observed alterations in body weight for females.
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Affiliation(s)
- Sam R. Moore
- Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Human Movement Science Curriculum, Department of Health Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Amanda N. Gordon
- Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Hannah E. Cabre
- Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Human Movement Science Curriculum, Department of Health Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Anthony C. Hackney
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Abbie E. Smith-Ryan
- Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Human Movement Science Curriculum, Department of Health Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Correspondence: ; Tel.: +1-919-962-2574
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Li Y, Zang Y, Zhao X, Liu L, Qiu Q, Ouyang K, Qu M. Dietary Supplementation With Creatine Pyruvate Alters Rumen Microbiota Protein Function in Heat-Stressed Beef Cattle. Front Microbiol 2021; 12:715088. [PMID: 34512594 PMCID: PMC8431830 DOI: 10.3389/fmicb.2021.715088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 07/26/2021] [Indexed: 11/13/2022] Open
Abstract
Creatine pyruvate (CrPyr) is a new multifunctional nutrient that can provide both pyruvate and creatine. It has been shown to relieve the heat stress of beef cattle by improving antioxidant activity and rumen microbial protein synthesis, but the mechanism of CrPyr influencing rumen fermentation remains unclear. This study aimed to combine 16S rDNA sequencing and metaproteomics technologies to investigate the microbial composition and function in rumen fluid samples taken from heat-stressed beef cattle treated with or without 60 g/day CrPyr. 16S rDNA sequencing revealed that there were no significant differences in the α-diversity indices between the two groups. By analyzing the level profiles of 700 distinct proteins, we found that the CrPyr administration increased the expression of enzymes involved in specific metabolic pathways including (i) fatty acid β-oxidation; (ii) interconversion from pyruvate to phosphoenolpyruvate, oxaloacetate, acetyl-CoA, and malate; (iii) glycolysis/gluconeogenesis and citrate cycle metabolism; and (iv) biosynthesis of amino acids. These results indicated that the increased generation of adenosine triphosphate during fatty acid β-oxidation or citrate cycle and the up-regulation synthesis of microbial protein in rumen of beef cattle treated with CrPyr may help decrease oxidative stress, regulate energy metabolism, and further improve the rumen fermentation characteristic under heat stress.
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Affiliation(s)
- Yanjiao Li
- Jiangxi Province Key Laboratory of Animal Nutrition/Animal Nutrition and Feed Safety Innovation Team, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Yitian Zang
- Jiangxi Province Key Laboratory of Animal Nutrition/Animal Nutrition and Feed Safety Innovation Team, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Xianghui Zhao
- Jiangxi Province Key Laboratory of Animal Nutrition/Animal Nutrition and Feed Safety Innovation Team, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Lin Liu
- Jiangxi Province Key Laboratory of Animal Nutrition/Animal Nutrition and Feed Safety Innovation Team, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Qinghua Qiu
- Jiangxi Province Key Laboratory of Animal Nutrition/Animal Nutrition and Feed Safety Innovation Team, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Kehui Ouyang
- Jiangxi Province Key Laboratory of Animal Nutrition/Animal Nutrition and Feed Safety Innovation Team, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Mingren Qu
- Jiangxi Province Key Laboratory of Animal Nutrition/Animal Nutrition and Feed Safety Innovation Team, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
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Liu L, Zhang W, Yu H, Xu L, Qu M, Li Y. Improved antioxidant activity and rumen fermentation in beef cattle under heat stress by dietary supplementation with creatine pyruvate. Anim Sci J 2020; 91:e13486. [PMID: 33222328 DOI: 10.1111/asj.13486] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 10/19/2020] [Accepted: 10/22/2020] [Indexed: 11/30/2022]
Abstract
Pyruvate and creatine, energetics and antioxidant substances, can promote rumen fermentation and metabolism. This study aimed to evaluate the stress resistance and rumen fermentation effects of the compound creatine pyruvate (CrPyr) in diets for beef cattle under heat stress. Four Jinjiang steers fitted with permanent rumen cannulas were used in a 4 × 4 Latin square design and fed a diet supplemented with CrPyr at 0, 20, 40, or 60 g/d. Heat stress was employed for 62 of 64 days. Supplementing with CrPyr elevated their levels of free triiodothyronine and triiodothyronine, superoxide dismutase activity, ruminal pH value, microbial crude protein concentration, crude fat digestibility, nitrogen intake, and levels of urine allantoin and total purine derivatives. It also reduced their levels of cortisol and corticosterone, malondialdehyde concentration, lactate dehydrogenase activity, and urine nitrogen excretion. In conclusion, CrPyr relieves the heat stress of beef cattle by improving antioxidant activity and rumen microbial protein synthesis.
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Affiliation(s)
- Lin Liu
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Wenjing Zhang
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Hanjing Yu
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Lanjiao Xu
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Mingren Qu
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
| | - Yanjiao Li
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang, China
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Nutrition and Supplementation Considerations to Limit Endotoxemia When Exercising in the Heat. Sports (Basel) 2018; 6:sports6010012. [PMID: 29910316 PMCID: PMC5969196 DOI: 10.3390/sports6010012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/25/2018] [Accepted: 01/31/2018] [Indexed: 02/07/2023] Open
Abstract
Exercise-induced heat production is further elevated by exercise performed in hot conditions and this can subsequently impact inflammation, and gastrointestinal (GI) health. Implementing nutrition and supplementation strategies under these conditions may support the hyperthermic response, the systemic inflammatory response, GI permeability and integrity, and exercise performance. Therefore, the aim of this brief review is to explore athletes' inflammatory response of two key biomarkers, lipopolysaccharide (LPS), and interleukin-6 (IL-6), and provide nutrition and supplementation recommendations when exercising in hot conditions. There is emerging evidence that probiotics, glutamine, and vitamin C can preserve GI integrity, which may improve performance during exercise in the heat. Glucose rich food when consumed with water, before and during exercise in the heat, also appear to limit endotoxemia, preserve GI integrity, and reduce the incidence of GI disturbances compared with water alone. The use of non-steroidal anti-inflammatory drugs (NSAIDs) may compromise GI integrity and this may result in greater leakage of endotoxins during long duration exercise in the heat. Further work is required to elucidate the impact of nutrition and supplementation strategies, in particular the use of NSAIDs, when exercising in the heat.
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Havenetidis K. The use of creatine supplements in the military. J ROY ARMY MED CORPS 2015; 162:242-8. [DOI: 10.1136/jramc-2014-000400] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 03/08/2015] [Indexed: 01/06/2023]
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Alhidary IA, Shini S, Al Jassim RAM, Abudabos AM, Gaughan JB. Effects of selenium and vitamin E on performance, physiological response, and selenium balance in heat-stressed sheep1. J Anim Sci 2015; 93:576-88. [DOI: 10.2527/jas.2014-8419] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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Antonio J, Ciccone V. The effects of pre versus post workout supplementation of creatine monohydrate on body composition and strength. J Int Soc Sports Nutr 2013; 10:36. [PMID: 23919405 PMCID: PMC3750511 DOI: 10.1186/1550-2783-10-36] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 07/10/2013] [Indexed: 01/07/2023] Open
Abstract
Background Chronic supplementation with creatine monohydrate has been shown to promote increases in total intramuscular creatine, phosphocreatine, skeletal muscle mass, lean body mass and muscle fiber size. Furthermore, there is robust evidence that muscular strength and power will also increase after supplementing with creatine. However, it is not known if the timing of creatine supplementation will affect the adaptive response to exercise. Thus, the purpose of this investigation was to determine the difference between pre versus post exercise supplementation of creatine on measures of body composition and strength. Methods Nineteen healthy recreational male bodybuilders (mean ± SD; age: 23.1 ± 2.9; height: 166.0 ± 23.2 cm; weight: 80.18 ± 10.43 kg) participated in this study. Subjects were randomly assigned to one of the following groups: PRE-SUPP or POST-SUPP workout supplementation of creatine (5 grams). The PRE-SUPP group consumed 5 grams of creatine immediately before exercise. On the other hand, the POST-SUPP group consumed 5 grams immediately after exercise. Subjects trained on average five days per week for four weeks. Subjects consumed the supplement on the two non-training days at their convenience. Subjects performed a periodized, split-routine, bodybuilding workout five days per week (Chest-shoulders-triceps; Back-biceps, Legs, etc.). Body composition (Bod Pod®) and 1-RM bench press (BP) were determined. Diet logs were collected and analyzed (one random day per week; four total days analyzed). Results 2x2 ANOVA results - There was a significant time effect for fat-free mass (FFM) (F = 19.9; p = 0.001) and BP (F = 18.9; p < 0.001), however, fat mass (FM) and body weight did not reach significance. While there were trends, no significant interactions were found. However, using magnitude-based inference, supplementation with creatine post workout is possibly more beneficial in comparison to pre workout supplementation with regards to FFM, FM and 1-RM BP. The mean change in the PRE-SUPP and POST-SUPP groups for body weight (BW kg), FFM (kg), FM (kg) and 1-RM bench press (kg) were as follows, respectively: Mean ± SD; BW: 0.4 ± 2.2 vs. 0.8 ± 0.9; FFM: 0.9 ± 1.8 vs. 2.0 ± 1.2; FM: -0.1 ± 2.0 vs. −1.2 ± 1.6; Bench Press 1-RM: 6.6 ± 8.2 vs. 7.6 ± 6.1. Qualitative inference represents the likelihood that the true value will have the observed magnitude. Furthermore, there were no differences in caloric or macronutrient intake between the groups. Conclusions Creatine supplementation plus resistance exercise increases fat-free mass and strength. Based on the magnitude inferences it appears that consuming creatine immediately post-workout is superior to pre-workout vis a vis body composition and strength.
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Affiliation(s)
- Jose Antonio
- Exercise and Sports Sciences, Nova Southeastern University, 3532 S. University Drive, University Park Plaza Suite 3532, Davie, FL 33314, USA
| | - Victoria Ciccone
- Exercise and Sports Sciences, Nova Southeastern University, 3532 S. University Drive, University Park Plaza Suite 3532, Davie, FL 33314, USA
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Alhidary IA, Shini S, Al Jassim RAM, Gaughan JB. Physiological responses of Australian Merino wethers exposed to high heat load. J Anim Sci 2011; 90:212-20. [PMID: 21841087 DOI: 10.2527/jas.2011-3972] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Twelve 9-mo-old Merino wethers (30.4 ± 3.2 kg of BW) were used in a crossover study to investigate the heat tolerance of Australian Merino sheep by testing their physiological responses to repeated heat loads that occurred during summer months. Wethers were randomly divided into 2 groups of 6 wethers each, housed individually in an environmental chamber, and subjected to 2 d of thermoneutral conditions (TNC) followed by either 7 d of TNC (maximum temperature of 24°C, minimum temperature of 16°C) or 7 d of hot conditions (maximum temperature of 38°C, minimum temperature of 28°C), and then 2 d of TNC. These treatments were applied in 2 replicates, with each replicate in a separate environmental chamber. Rectal temperature (RT) and respiration rate were measured daily at 0600, 0800, 1000, 1200, 1400, 1600, and 1800 h. Feed and water intakes were measured daily, and wethers were weighed on d 1 and 11. Blood samples were collected from each whether on d 2 and 6, and serum was assayed for concentrations of creatine, glucose, total protein, cholesterol, NEFA, calcium, sodium, and potassium. Exposure to a high ambient temperature resulted in an 0.8°C increase in RT (P < 0.001), an increase in respiration rate (P < 0.001) by 66 breaths/min, and a 2.7 L/d increase in water intake (P < 0.0001). Feed intake decreased by 22% (P < 0.0001), BW decreased by 5.2% (P < 0.03), and creatine concentration was reduced (P < 0.05). No differences (P > 0.05) between treatments were observed for any of the remaining serum variables. These results indicate that Australian Merino sheep were able to maintain RT within the normal range during exposure to a prolonged increase in heat and that they recovered quickly from the negative effect of heat stress within 2 d of conditions returning to TNC. It would appear that they have a high heat tolerance, and further studies are needed to examine the effects of a greater heat load to determine the temperature-humidity index thresholds for Australian Merino sheep.
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Affiliation(s)
- I A Alhidary
- Department of Animal Production, College of Food Science and Agriculture, King Saud University, Riyadh 11451, Saudi Arabia.
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Lopez RM, Casa DJ. The influence of nutritional ergogenic aids on exercise heat tolerance and hydration status. Curr Sports Med Rep 2009; 8:192-9. [PMID: 19584606 DOI: 10.1249/jsr.0b013e3181ae4f66] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Exercise in the heat may predispose an athlete to an exertional heat illness. It is imperative to be knowledgeable on the influence of various nutritional supplements on exercise tolerance and hydration status. Because of the variety of nutritional ergogenic aids that are easily accessible to athletes, medical and health professionals must rely on empirical evidence when making conclusions about the efficacy of a supplement while not ignoring significant anecdotal reports that may resemble real-life situations more closely.
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Affiliation(s)
- Rebecca M Lopez
- Human Performance Laboratory, Department of Kinesiology, Neag School of Education, University of Connecticut, Storrs, Connecticut 06269-1110, USA.
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Lopez RM, Casa DJ, McDermott BP, Ganio MS, Armstrong LE, Maresh CM. Does creatine supplementation hinder exercise heat tolerance or hydration status? A systematic review with meta-analyses. J Athl Train 2009; 44:215-23. [PMID: 19295968 DOI: 10.4085/1062-6050-44.2.215] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To critically assess original research addressing the effect of creatine supplementation on exercise heat tolerance and hydration status. DATA SOURCES We searched the electronic databases PubMed, Scopus, Web of Science, SPORTDiscus, and Rehabilitation & Physical Medicine, without date limitations, for the following key words: creatine, exercise, thermoregulation, dehydration, hyperthermia, heat tolerance, exertional heat illnesses, and renal function. Our goal was to identify randomized clinical trials investigating the effect of creatine supplementation on hydration status and thermoregulation. Citations from related articles also were identified and retrieved. DATA SYNTHESIS Original research was reviewed using the Physiotherapy Evidence Database (PEDro) Scale. One author initially screened all articles. Fifteen of 95 articles examined the effects of creatine on thermoregulation or hydration status (or both). Two independent reviewers then reviewed these articles. Ten studies were selected on the basis of inclusion and exclusion criteria. The PEDro scores for the 10 studies ranged from 7 to 10 points (maximum possible score = 10 points). CONCLUSIONS No evidence supports the concept that creatine supplementation either hinders the body's ability to dissipate heat or negatively affects the athlete's body fluid balance. Controlled experimental trials of athletes exercising in the heat resulted in no adverse effects from creatine supplementation at recommended dosages.
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Abstract
The literature on creatine supplementation supporting its efficacy has grown rapidly and has included studies in both healthy volunteers and patient populations. However, the first rule in the development of therapeutic agents is safety. Creatine is well-tolerated in most individuals in short-term studies. However, isolated reports suggest creatine may be associated with various side effects affecting several organ systems including skeletal muscle, the kidney and the gastrointestinal tract. The majority of clinical studies fail to find an increased incidence of side effects with creatine supplementation. To date, studies have not found clinically significant deviations from normal values in renal, hepatic, cardiac or muscle function. Few data are available on the long-term consequences of creatine supplementation.
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Affiliation(s)
- Adam M Persky
- Division of Pharmacotherapy and Experimental Therapeutics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7360, USA
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Abstract
Creatine monohydrate (creatine) has become an increasingly popular ingredient in dietary supplements, especially sports nutrition products. A large body of human and animal research suggests that creatine does have a consistent ergogenic effect, particularly with exercises or activities requiring high intensity short bursts of energy. Human data are primarily derived from three types of studies: acute studies, involving high doses (20 g/d) with short duration (< or = 1 week), chronic studies involving lower doses (3-5 g/d) and longer duration (1 year), or a combination of both. Systematic evaluation of the research designs and data do not provide a basis for risk assessment and the usual safe Upper Level of Intake (UL) derived from it unless the newer methods described as the Observed Safe Level (OSL) or Highest Observed Intake (HOI) are utilized. The OSL risk assessment method indicates that the evidence of safety is strong at intakes up to 5 g/d for chronic supplementation, and this level is identified as the OSL. Although much higher levels have been tested under acute conditions without adverse effects and may be safe, the data for intakes above 5 g/d are not sufficient for a confident conclusion of long-term safety.
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Affiliation(s)
- Andrew Shao
- Council for Responsible Nutrition, 1828 L St., NW, Suite 900,Washington, DC 20036-5114, USA.
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