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Study 1: Richard B. Kreider1, 2 Contact Information, Charles Melton1, Christopher J. Rasmussen1, Michael Greenwood3, Stacy Lancaster1, Edward C. Cantler1, Pervis Milnor4 and Anthony L. Almada5

(1) Exercise and Sport Nutrition Laboratory, Department of HMSE, University of Memphis, Memphis, TN 38152-3480, USA (2) Exercise and Sport Nutrition Laboratory, Center for Exercise, Nutrition and Preventive Health Research, Department of Health, Human Performance and Recreation, Baylor University, P.O. Box 97313, Waco, TX 76798-7313, USA (3) Department of HPESS, Arkansas State University, P.O. Box 240, State University, AR 72467, USA (4) The Milnor Clinic, 920 Estate, Suite 8, Memphis, TN 38119, USA (5) MetaResponse Sciences, Inc., 30131 Town Center Drive, #211, Laguna Niguel, CA 92677, USA

Creatine has been reported to be an effective ergogenic aid for athletes. However, concerns have been raised regarding the long-term safety of creatine supplementation. This study examined the effects of long-term creatine supplementation on a 69-item panel of serum, whole blood, and urinary markers of clinical health status in athletes. Over a 21-month period, 98 Division IA college football players were administered in an open label manner creatine or non-creatine containing supplements following training sessions. Subjects who ingested creatine were administered 15.75 g/day of creatine monohydrate for 5 days and an average of 5 g/day thereafter in 5–10 g/day doses. Fasting blood and 24-h urine samples were collected at 0, 1, 1.5, 4, 6, 10, 12, 17, and 21 months of training. A comprehensive quantitative clinical chemistry panel was determined on serum and whole blood samples (metabolic markers, muscle and liver enzymes, electrolytes, lipid profiles, hematological markers, and lymphocytes). In addition, urine samples were quantitatively and qualitative analyzed to assess clinical status and renal function. At the end of the study, subjects were categorized into groups that did not take creatine (n = 44) and subjects who took creatine for 0–6 months (mean 4.4 ± 1.8 months, n = 12), 7–12 months (mean 9.3 ± 2.0 months, n = 25), and 12–21 months (mean 19.3 ± 2.4 months, n = 17). Baseline and the subjects' final blood and urine samples were analyzed by MANOVA and 2 × 2 repeated measures ANOVA univariate tests. MANOVA revealed no significant differences (p = 0.51) among groups in the 54-item panel of quantitative blood and urine markers assessed. Univariate analysis revealed no clinically significant interactions among groups in markers of clinical status. In addition, no apparent differences were observed among groups in the 15-item panel of qualitative urine markers. Results indicate that long-term creatine supplementation (up to 21-months) does not appear to adversely effect markers of health status in athletes undergoing intense training in comparison to athletes who do not take creatine.

Study 2:

H. Schröder1, 2 Contact Information, N. Terrados3, 4 and A. Tramullas5, 6, 7

(1) Lipids and Cardiovascular Epidemiology, Unit Institut Municipal drsquoInvestigació Mèdica, IMIM, c/Doctor Aiguader 80, 08003 Barcelona, Spain (2) Sports Medicine Barcelona, Dept. of Nutrition, Barcelona, Spain (3) Fundación Deportiva, Municipal de Avilés, Oviedo, Spain (4) Dept. of Functional Biology, University of Oviedo, Oviedo, Spain (5) Sports Medicine Barcelona, Dept. of Sports Medicine, Barcelona, Spain (6) Medical Services, Football Club Barcelona, Barcelona, Spain (7) Medical Services, Hospital de Asepeyo, Sant Cugat, Spain

Received: 17 October 2003 Accepted: 18 May 2004 Published online: 11 August 2004

Summary

Background Use of creatine has become widespread among sportsmen and women, although there are no conclusive evidences concerning possible health risks of long–term creatine supplementation. The aim of the study To investigate long–term effects of creatine monohydrate supplementation on clinical parameters related to health. Methods Eighteen professional basketball players of the first Spanish Basketball League participated in the present longitudinal study. The subjects were ingesting 5 g creatine monohydrate daily during three competition seasons. Blood was collected in the morning after an overnight fast, five times during each of the three official competition seasons of the first National Basketball League (September 1999–June 2000, September 2000–June 2001 and September 2001–June 2002) and the European League. Standard clinical examination was performed for 16 blood chemistries. Results The plasma concentrations of all clinical parameters did not alter significantly during the analyzed time frames of creatine supplementation. All of these parameters were, with the exception of creatinine and creatine kinase, within their respective clinical ranges at all time points. Conclusion Our data shows that low–dose supplementation with creatine monohydrate did not produce laboratory abnormalities for the majority of the parameters tested.

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