Essentials of Creatine in Sports and Health PDF
Preview Essentials of Creatine in Sports and Health
ESSENTIALS OF CREATINE IN SPORTS AND HEALTH StrengthPro® is a proud sponsor ofthe International Society of Sports Nutrition. This textbook was made possible via an educational grant from StrengthPro®. ContactinformationforStrengthPro® www.strengthpro.com StrengthProInc. 6640 S. Tenaya WaySuite 150 LasVegas, NV89113 [email protected] ESSENTIALS OF CREATINE IN SPORTS AND HEALTH Edited by R. JEFFREY STOUT, PhD DepartmentofHealth andSports Science University ofOklahoma, Norman, Oklahoma JOSE ANTONIO, phD International Society ofSports Nutrition DeerfieldBeach, Florida and DOUGLAS KALMAN, PhD, RD Division ofNutrition andEndocrinology Miami ResearchAssociates Miami, Florida H P ,\1', umana ress 7),\' ©2008HumanaPressInc.,apartofSpringerScience+BusinessMedia 999RiverviewDrive,Suite208 Totowa,NewJersey07512 Allrightsreserved. Nopartofthisbookmaybereproduced,storedinaretrievalsystem,or transmittedinanyformorbyanymeans,electronic,mechanical,photocopying,microfilming, recording,orotherwisewithoutwrittenpermissionfromthePublisher. Allauthoredpapers,comments,opinions,conclusions,orrecommendationsarethoseofthe author(s),anddonotnecessarilyreflecttheviewsofthepublisher. CoverdesignbyShirleyKarina. ProductionEditor:AmyThau Foradditionalcopies,pricingforbulkpurchases,and/orinformationaboutother Humanatitles,contactHumanaattheaboveaddressoratanyofthefollowingnumbers: Tel.:973-256-1699;Fax:973-256-8341;orvisitourwebsiteathttp://humanapress.com Thispublicationisprintedonacid-freepaper.@ ANSIZ39.48-1984(AmericanNationalStandardsInstitute)PermanenceofPaperforPrinted LibraryMaterials. PhotocopyAuthorizationPolicy: Authorizationtophotocopyitemsforinternalorpersonaluse,ortheinternalorpersonaluse ofspecificclients,isgrantedbyHumanaPressInc.,providedthatthefeeofUS$30.00per copyispaiddirectlytotheCopyrightClearanceCenterat222RosewoodDrive,Danvers,MA 01923.ForthoseorganizationsthathavebeengrantedaphotocopylicensefromtheCCC,a separatesystemofpaymenthasbeenarrangedandisacceptabletoHumanaPressInc.Thefee codeforusersoftheTransactionalReportingServiceis: [978-1-58829-690-0/08$30.00]. PrintedintheUnitedStatesofAmerica. 10 9 8 7 6 5 4 3 2 1 elSBN 13:978-1-59745-573-2 LibraryofCongressControlNumber: 2007940765 Preface The Dietary Supplement Industry is a booming $21.3 billion dollar industry in the United States alone. This industry includes vitamins, minerals, herbs, specialtysupplements,meal replacementpowdersand bars, as well as sports nutrition and weight loss supplements. There is perhaps no single ingredient in the history ofdietary supplements that has been studies more thoroughly than creatine monohydrate. In a nutshell, creatine works and is safe. A PubMed search of"creatine monohydrate" alone brings up 234 research articles, and there are cer tainly many more peer-reviewed publications on creatine that do not appear on the NLM and NIH databases. With all of the misinformation regarding the effects of creatine supplementation on health and sports performance, Essentials of Creatine in Sports andHealth brings together the information on how creatine affecs body composition, exercise performance, and health. Supported by the International Society ofSports Nutrition, this book is timely and vital for all professionals in the field ofsports nutrition. Propersupplementationwithcreatinecanimproveperformanceinboth enduranceandstrength-powersports(seechaptersbyDrs. Willoughby and Cramer). As far as safety, perhaps no othersingle supplement has been shown to be extraordinarily safe while still being effective. Dr. Poortmans' chapter edifies the reader on the safety and health data regarding creatine. This text will bring the student, academic scientist, clinician, and sports nutritionist up to date on the latest science ofcreatine, as well as dispel the common myths that have pervadedthe mainstream press regarding this truly remarkable ergogenic aid. Jeffrey R. Stout, PhD Jose Antonio, PhD Douglas Kalman, PhD, RD v Contents Preface v Contributors ix 1 An Overview ofCreatine Metabolism 1 JeffS. Volek, Kevin D. Ballard, andCassandra E. Forsythe 2 Creatine Supplementation in Strength-Power Sports 25 Darryn S. Willoughby 3 Creatine Supplementation in Endurance Sports .45 Joel P. Cramer 4 Creatine Supplementation and Woman Athletes 101 Joan Eckerson 5 Creatine Consumption and Health 127 Jacques R. Poortmans andMarc Francaux 6 Clinical Application 173 Joseph Weir 7 Creatine Overview: Facts, Fallacies, andFuture 211 Mike Greenwood Index 241 vii Contributors JOSE ANTONIO, PhD • International Society ofSports Nutrition, Boca Raton, Florida JOEL T. CRAMER, PhD· DepartmentofHealth andExercise Science, University ofOklahoma, Norman, Oklahoma KEVIN D. BAllARD, MS • DepartmentofKinesiology, University ofConnecticut, Storrs, Connecticut JOAN ECKERSON, PhD· DepartmentofExercise Science andAthletic Training, Creighton University, Omaha, Nebraska CASSANDRA E. FORSYTHE, MS • DepartmentofKinesiology, University ofConnecticut, Storrs, Connecticut MARC FRANCAUX, PhD· Institut Superieurd'Education Physique etde Readaption, Faculte de Medecine, Universite Catholique de Louvain, Louvain-la-neuve, Belgium MIKE GREENWOOD, PhD • Department ofHealth, Human Performance, andRecreation. Baylor University, Waco, Texas DOUGLAS KALMAN, PhD, RD • Division ofNutrition andEndocrinology, Miami Research Associates, Miami, Florida JACQUES R. POORTMANS, PhD· Institut Superieurd'Education Physique etde Kinesitherapie, Universite Librede Bruxelles, Brussels, Belgium JEFFREY R. STOU1, PhD· Department ofHealth andSports Science [/niversity olOklahoma. Norman, Oklahoma .JEfF S. VOlEK, PhD, RD • Department o/Kinesiology, Universit,v o/Connecticut, Storrs, Connecticut JOSEPH P. WEIR, PhD· Physical Therapy Program, Des Moines University~Osteopathic Medical Center, Des Moines, Iowa DARRYN S. WillOUGHBY, PhD • DepartmentofHealth, Human Performance. andRecreation, Baylor University, Waco, Texas ix 1 Overview ofCreatine Metabolism JeffS. Volek, PhD, RD, Kevin D. Ballard, and MS, Cassandra E. Forsythe, MS 1. INTRODUCTION Creatine (Cr) was first discovered as an organic constituent ofmeat some time in the early 1800s. Later in the 1800s, Cr was consistently detected in muscle tissue extracted from various mammals. It was noted that foxes killed in a hunt immediately after running, contained significantly more Cr than normaL providing the first indication that muscular contraction results in an accumulation of Cr. Around the same time, a substance called creatinine (Crn) was detected in the urine and later determined to be a breakdown product of Cr. Phosphocreatine (PCr) was first isolated from muscle tissue in 1927 and found to play an important role in the transfer ofenergy. Around the same time, two researchers who consumed large quantities of Cr noted that a percentage of the Cr ingested could not be accounted for by excretion in the urine (J). This study was one ofthe first to indicate that "Cr loading'" in muscle is possible when large amounts of Cr are consumed. A great deal of research has been done since this early work to further define the importance ofCrin humans, and the impact ofCrsupplementation. In this chapter,the basicmetabolism andfunction of Cr in humans will be overviewed. To what extent and what factors influence blood- and muscle-Cr levels in response to Cr supplementa tion will be discussed. Also some of the proposed mechanisms that account for the ergogenic effects from Cr usage observed in many studies will be explored. From: EssentialsofCreatine in SportsandHealth Edited by: J. R. Stout. J. Antonioand D. Kalman © HumanaPress Inc..Totowa, NJ 1 2 VoleketaI. Fig. 1.StructureofCr. 2. LITERATURE REVIEW Cr (Fig. 1), also known as methylguanidino acetic acid, is a term derived from the Greek work kreas, meaning flesh. Indeed, the highest quantities (-94%) ofCr are in muscular tissues, such as skeletal mus cleandheart(2).Crisanexampleofaphysiologicallyimportantnitroge nous compound synthesized from amino acids. However, because rates ofCrbiosynthesis are sufficientto maintain normal Crlevels, Cris not consideredanessentialdietary nutrient. Cris also notconsideredapro tein, even though it contains nitrogen and is made from amino acids. Unlike proteins, Cr synthesis does not involve formation of peptide bonds and its degradation does not involve deamination (removal of nitrogen) when it is excreted by the kidney. Thus, the concern that Cr poses a threat to renal function because itrepresents a nitrogen loadon the kidney is unlikely and has not been substantiated (for more infor mation, see Chapter5). 2.1. Endogenous Cr Synthesis In all mammals, muscle tissues do not have the ability to synthesize Cr, so the compound must be taken up from the blood originating from endogenous biosynthesis or dietary sources. Synthesis ofCr in humans occurs primarily in the liver, from the conditionally essential amino acid arginine, the nonessential amino acid glycine, and the potent methyl donor, S-adenosyl-methionine(SAM) (2).Thefirst stepinCrbiosynthe sisinvolvestransferoftheamidinogroupofarginine to glycine, forming L-ornithine and guanidinoacetic acid. This reaction is catalyzed by the enzyme L-arginine:glycine amidinotransferase (AGAT). In the next step, guanidinoacetic acid is methylated by SAM through the action of the
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