Creatine is a naturally occurring compound found in skeletal muscle (and the brain). Around one gram of creatine a day is synthesised in the liver and approximately two grams are lost daily in the urine. Creatine is also obtained through dietary intake mostly from meat and fish (1). There is large individual variation in endogenous creatine levels due to gender, age and dietary habits (vegetarians have lower levels of muscle creatine than meat eaters). A typical carnivorous diet supplies 1 to 2 g of creatine per day (2). Its ironic that one of the most popular sports supplements on the market is naturally made in our liver, kidneys and pancreas (3,4). So why do we want more of it?
Creatine has a role in the regulation of energy production and acts indirectly to help supply the body with ATP (the body’s fuel currency). Increased creatine stores can potentially enhance fatigue resistance by acting as a buffer for hydrogen ions produced during energy metabolism and thereby decrease acidosis (6). An enhanced time to fatigue is likely to lead to performance improvements during high-intensity, brief duration (<30 second) activities with short recovery periods. In summary supplementation can keep the anaerobic system running efficiently under short bouts of intense activity.
Who might benefit from creatine supplementation
Athletes who participate in sports with high anaerobic requirements with repeated brief, high intensity efforts or intermittent work patterns such as team sports, criterium bike racing, Cross-Fit, HYROX, middle distance running/swimming, racquet sports, boxing/marshal arts, sprinting and more, are most likely to benefit from creatine supplementation.
Sportspeople undertaking resistance training programs to increase lean muscle mass are also likely to benefit from supplementation. It should be noted individual responses to creatine are varied. Individuals with the lowest starting creatine stores have the greatest potential for a response to supplementation.
Recommended dosing strategy
Supplementation with creatine involves both a loading and maintenance phase (saturated muscle takes approximately 4 weeks to return to baseline levels). Loading can be done over a short (5 day) or slow (28 day) period followed by an ongoing maintenance dose (7,8). Each dose should be taken with a generous portion of carbohydrate to enhance uptake and storage of creatine in the muscles.
Dosage = 20 g/day (or 0.3 g/kg body mass/day) in four to five divided doses for five to seven days followed by a maintenance dose of 2-5 g/day (0.03 g/kg/day) for the next few months (5).
Potential side effects
Acute loading is typically associated with a small weight gain (~600-1000g) which may be counterproductive to athletes competing in sports where power-to-weight ratio is important (8). Anecdotal reports of muscle cramps, strains and tears but little evidence to substantiate an increased risk of these events.
It is important to note that the safety of creatine supplementation has not been studied in children and adolescents.
References
(1) 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.
(2) Jayasena DD, Jung S, Bae YS, et al. Changes in endogenous bioactive compounds of Korean native chicken meat at different ages and during cooking. Poult Sci. 2014;93:1842-1849.
(3) Momaya A, Fewal M, Estes R. Performance-enhancing substances in sports: a review of the literature. Sports Med. 2015;45:517-531
(4) 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.
(5) Bemben MG, Lamont HS. Creatine supplementation and exercise performance. Sports Med. 2005;35:107-125. Abstract available from: http://www.ncbi.nlm.nih.gov.ezproxy.uow.edu.au/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=15707376
(6) Butts J, Jacobs B, Silvis M. Creatine Use in Sports. Sports Health. 2018 Jan/Feb;10(1):31-34. doi: 10.1177/1941738117737248. Epub 2017 Oct 23. PMID: 29059531; PMCID: PMC5753968.
(7) Devries M, Phillips S. Creatine supplementation during resistance training in older adults—a meta-analysis. Med Sci Sports Exerc. 2014;46:1194-1203.
(8) Sports Dietitians Australia [SDA], available from; https://www.sportsdietitians.com.au/factsheets/supplements/creatine-athletes/
Ashley Thomas
Dietitian and Nutritionist (Masters)
Bachelor of Physical and Health Education
Instagram: ashthomo_nutrition
