title: Effects of creatine supplementation along with resistance training on urinary formaldehyde and serum enzymes in wrestlers.
abstract: BACKGROUND
  Formaldehyde is a cytotoxic agent produced from creatine through a metabolic pathway, and in this regard, it has been claimed that creatine supplementation could be cytotoxic. Even though the cytotoxic effects of creatine supplementation have been widely studied, yet little is known about how resistance training can alter these toxic effects. This study aimed to determine the effects of short-term creatine supplementation plus resistance training on the level of urinary formaldehyde and concentrations of serum enzymes in young male wrestlers.
  
  
  METHODS
  In a double-blind design twenty-one subjects were randomized into creatine supplementation (Cr), creatine supplementation plus resistance training (Cr + T) and placebo plus resistance training (Pl + T) groups. Participants ingested creatine (0.3 g/kg/day) or placebo for 7 days. The training protocol consisted of 3 sessions in one week, each session including three sets of 6-9 repetitions at 80-85% of one-repetition maximum for whole-body exercise. Urine and blood samples were collected at baseline and at the end of the supplementation.
  
  
  RESULTS
  Creatine supplementation significantly increased the excretion rate of urinary formaldehyde in the Cr and Cr + T groups by 63.4% and 30.4%, respectively (P<0.05), indicating that resistance training could partially lower this rate by 17.7%. No significant differences were detected in the levels of serum enzymes across time and groups (P>0.05).
  
  
  CONCLUSIONS
  These findings indicate that resistance training may lower the increase of urinary formaldehyde excretion induced by creatine supplementation, suggesting that creatine consumption could be relatively less toxic when combined with resistance training.
authors.affiliation: Faculty of Physical Education and Exercise Sciences, University of Tabriz, Tabriz, Iran - naseri_azadeh@yahoo.com.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Nasseri
authors.forename: Afshar
authors.initials: A
authors.lastname: Jafari
mesh_terms: D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D003401:Creatine / Q000009:adverse effects* / Q000378:metabolism; D003402:Creatine Kinase / Q000097:blood; D019587:Dietary Supplements / Q000009:adverse effects*; D004311:Double-Blind Method; D005557:Formaldehyde / Q000652:urine*; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008297:Male; D011897:Random Allocation; D055070:Resistance Training / Q000379:methods*; D014952:Wrestling; D055815:Young Adult
chemical_list: D005557:Formaldehyde; D007770:L-Lactate Dehydrogenase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D003402:Creatine Kinase; D003401:Creatine