|Health and Safety Related Issues|
What are the possible side effects of creatine supplementation?
Research conducted on potential side effects of creatine supplementation focuses on three areas:
Supplementation and Musculotendinous Stiffness Watsford et al., 2003
Dehydration and Heat Illness
An anecdotal claim is that creatine supplementation increases the risk of dehydration and heat illness because it retains water in muscles that are need to regulate and maintain homeostasis in other regions of the body. Volek et al. (2001) examined this claim testing 20 healthy men who either supplemented with creatine (.3g/kg body weight) or a placebo for 7 days. The men performed a 30 minute cycling test at 60 - 70% of their VO2 max followed with three 10 second sprints in an environmental chamber at a temperature of 37*C and 80% humidity. Data collected for heart rate, blood pressure, sweat rate, rectal temperature showed no differences between the creatine and placebo groups. There were also no symptoms of cramping for either group. The creatine group also had higher increases of peak power during the cycling test then the placebo group. Research has developed several suggestions in regards to creatine loading prior to exercise.
Anecdotal reports also state that creatine supplementation has a negative effect on kidney function. However, research has found that this is not the case.
Kreider et al. (2003) examined for a 21 month period the effects of creatine supplementation on renal function in 98 collegiate NCAA Division IA football players by collecting data on blood variables (muscle and liver enzymes, electrolytes, lipid profiles) and urinary measures. The subjects were placed into 1 of 4 groups: 1.) non-users, 2.) users for 0 - 6 months, 3.) users for 7 - 12 months, and 4.) users for 12 - 21 months. No differences in blood or urinary analysis were shown between the groups and all of the results were within normal ranges (Rawson et al., 2003).
Research by Schilling et al. (2001) also confirmed that creatine supplementation did not effect kidney function. His study consisted of 26 collegiate athletes who supplemented creatine. The kidney function tests were within normal ranges for every athlete (Mottram, 2003).
Due to the lack of research regarding
the effects of creatine supplementation on pre-existing and recognized
kidney dysfunction individuals with these conditions are advised to avoid
creatine supplementation (Taes
et al., 2003).
Creatine's Effects on Hepatic (Liver) Function
Studies also show that creatine
supplementation does not effect liver function. Waldron et al. studied
the effects of creatine supplementation on liver function of 8 subjects
during a 5 week high intensity exercise routine. There were no reports
of changes in alanine aminotransferase (ALT), aspartate aminotransferase
(AST), alkaline phosphate, albumin, creatinine, or total bilirubin.
(Robinson et al., 2000)
Miscellaneous Informational Links
FDA report on long term safety of creatine monohydrate
is Creatine Monohydrate? / Metabolism
and Storage of Creatine / Energy
Creatine Loading / Creatine,
Exercise, and Sport Performance /Health
and Safety Related Issues / Age,
Gender, and Creatine Supplementation / Creatine
and Clinical Use / Additional
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