Low-dose creatine combined with protein during resistance training in older men.
OBJECTIVE
To determine whether low-dose creatine and protein supplementation during resistance training (RT; 3 d x wk(-1); 10 wk) in older men (59-77 yr) is effective for improving strength and muscle mass without producing potentially cytotoxic metabolites (formaldehyde).


METHODS
Older men were randomized (double-blind) to receive 0.1 g x kg(-1) creatine + 0.3 g x kg(-1) protein (CP; n = 10), creatine (C; n = 13), or placebo (PLA; n = 12) on training days. Measurements before and after RT included lean tissue mass (air-displacement plethysmography), muscle thickness (ultrasound) of elbow, knee, and ankle flexors and extensors, leg and bench press strength, and urinary indicators of cytotoxicity (formaldehyde), myofibrillar protein degradation [3-methylhistidine (3-MH)],and bone resorption [cross-linked N-telopeptides of type I collagen (NTx)].


RESULTS
Subjects in C and CP groups combined experienced greater increases in body mass and total muscle thickness than PLA (P < 0.05). Subjects who received CP increased lean tissue mass (+5.6%) more than C (+2.2%) or PLA (+1.0%; P < 0.05) and increased bench press strength (+25%) to a greater extent than C and PLA combined (+12.5%; P < 0.05). CP and C did not differ from PLA for changes in formaldehyde production (+24% each). Subjects receiving creatine (C and CP) experienced a decrease in 3-MH by 40% compared with an increase of 29% for PLA (P < 0.05) and a reduction in NTx (-27%) versus PLA (+13%; P = 0.05).


CONCLUSIONS
Low-dose creatine combined with protein supplementation increases lean tissue mass and results in a greater relative increase in bench press but not leg press strength. Low-dose creatine reduces muscle protein degradation and bone resorption without increasing formaldehyde production.
Candow
Darren G
DG
Faculty of Kinesiology and Health Studies, University of Regina, Regina, Saskatchewan, Canada.
Little
Jonathan P
JP
Chilibeck
Philip D
PD
Abeysekara
Saman
S
Zello
Gordon A
GA
Kazachkov
Michael
M
Cornish
Stephen M
SM
Yu
Peter H
PH
D000368:Aged; D001862:Bone Resorption / Q000378:metabolism; D003401:Creatine / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005557:Formaldehyde / Q000032:analysis / Q000652:urine; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D009210:Myofibrils / Q000378:metabolism; D010919:Placebos; D055070:Resistance Training
D004044:Dietary Proteins; D010919:Placebos; D005557:Formaldehyde; D003401:Creatine