International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine.

Creatine Supplementation in Exercise, Sport, and Medicine: A Brief Review

1. Introduction

Creatine is a non-protein amino acid compound that is naturally present in red meat and seafood. Roughly 1–2% of intramuscular creatine is degraded daily to creatinine, which should be replaced with 1–3 g of creatine per day. This can be further emphasised in vegetarians who have generally lower baseline stores of creatine, and are thought to benefit more than omnivores when supplemented.

2. Mechanisms of Action

Metabolic Function: Creatine and phosphate (Pi) combine to creatine kinase (CK) to generate phosphocreatine (PCr), which, when sodium hydroxide (NaOH) is added to latter, makes ATP available during high-intensity exercise.

Uptake: After transport into muscle cells by creatine transporters (CRTR), creatine stimulates glycolytic ATP production and increases cytosolic ATP/ADP ratio.

Supplementing Effects: Raises muscle creatine and PCr levels by 20-40%, and plasma levels peak approximately 60min following ingestion.

3. Ergogenic Benefits in Sports

Response: Creatine monohydrate (CrM) is the most effective nutritional supplement (ergogenic aid) available to athletes to improve high intensity exercise capacity and muscle lean mass during training.

Benefits extend to men and women of all ages, and both trained and untrained individuals. Loading Protocol Loading of 0.3 to 5 g/kg/day for 5 to 7 days (or 3 to 5 g/day for 3 to 4 weeks) saturates muscle stores. Co-ingestion with carbs/protein enhances retention.

Recovery & Injury Prevention: Decreases muscle damage (↓ CK, LDH, TNF-α), speeds rehab, and decreases chance of injury to athletes.

4. Clinical Applications

Neuromuscular & Metabolic Disorders: Better outcomes in creatine deficiency syndromes, gyrate atrophy, and type 2 diabetes (↓ HbA1c, ↑ GLUT-4 translocation).

Cardio protection: Phosphocreatine in cardioplegic solutions prevents ischemic arrhythmias.

Neuro protection: May protect against damage from TBI, concussions, and spinal cord injuries. Aging & Sarcopenia: Protects lean mass, strength, and bone density in elderly.

5. Safety and Tolerability

Adverse Reactions: The sole reported effect is weight gain (mostly secondary to water accumulation). There is no evidence for altered renal function, dehydration or gastro intestinal (GI) complaints in healthy populations.

Chronic Use: Doses of up to 30 g per day over 5 years have no side effects in clinical trials. Special Populations: Safety in children, adolescents, and pregnant women, (neonatal benefits reported in animal models).

6. Practical Recommendations

For Athletes: 3-5 g/d CrM PO post-exercise has been reported to optimise load/performance and recovery.

Clinical Application: High doses (0.5 to 0.8 g/kg/day) are acceptable in patients.

Myths Debunked: There are no substantiated claims that any other forms of CrM are better or safer.

7. Conclusion

CrM is still the benchmark by which other substances, for performance and in health related applications, are compared. Public policy must be based on evidence, not misinformation, to promote safe and informed use.

Reference:

Kreider, R.B., Kalman, D.S., Antonio, J., Ziegenfuss, T.N., Wildman, R., Collins, R., Candow, D.G., Kleiner, S.M., Almada, A.L. and Lopez, H.L., 2017. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Journal of the

International Society of Sports Nutrition, 14(1), p.18.