Impact of differing protein sources and a creatine containing nutritional formula after 12 weeks of resistance training.
OBJECTIVE
We evaluated whether colostrum (Col) or an isocaloric and isonitrogenous blend of whey and casein in addition to creatine (Cr) affects body composition, muscular strength and endurance, and anaerobic performance during resistance training.


METHODS
Forty-nine resistance-trained subjects participated in a standardized 12-wk total body resistance training program. In a double-blind and randomized manner, subjects supplemented their diet with a protein control (Pro), Pro/Col, Pro/Cr, or Col/Cr. Supplements were isocaloric and isonitrogenous and provided 60 g/d of casein/whey (Pro) or Col as the protein source. At 0, 8, and 12 wk of supplementation, subjects were weighed, had body composition determined using dual-energy X-ray absorptiometry (DXA), performed one-repetition maximum (1RM) and 80% of 1RM tests on the bench press and leg press, and 30-s anaerobic sprint capacity tests. Data (mean +/- SD) were analyzed by repeated measures analysis of variance and reported as raw data in all tables and as changes from baseline for all figures for the Pro, Pro/Col, Pro/Cr, and Col/Cr groups, respectively.


RESULTS
Resistance training increased 1RM strength, muscular endurance, and anaerobic sprint capacity equally in all groups. Significant main and interaction effects (P < 0.05) were found for body mass, DXA total scanned mass, and fat-free mass (FFM; lean plus bone), whereas no changes (P > 0.05) were noted for fat mass, percent fat, or bone content. Post hoc analysis showed that, compared with Pro, subjects ingesting Pro/Col, Pro/Cr, and Col/Cr showed greater gains in body mass and DXA total scanned mass. Subjects ingesting Pro/Cr and Col/Cr had greater increases in FFM during training in comparison with Pro/Col.


CONCLUSIONS
In conjunction with 12 wk of resistance training, ingestion of Col or a blend of whey and casein protein with a vitamin/mineral supplement containing Cr resulted in greater improvements in FFM in comparison with Pro and Pro/Col.
Kerksick
Chad M
CM
Applied Biochemistry and Molecular Physiology Laboratory, Health and Exercise Science Department, University of Oklahoma, Norman, Oklahoma, USA. chad_kerksick@ou.edu
Rasmussen
Chris
C
Lancaster
Stacy
S
Starks
Michael
M
Smith
Patty
P
Melton
Charlie
C
Greenwood
Mike
M
Almada
Anthony
A
Kreider
Richard
R
D015502:Absorptiometry, Photon / Q000379:methods; D000273:Adipose Tissue / Q000254:growth & development / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001823:Body Composition / Q000187:drug effects*; D002364:Caseins; D003126:Colostrum; D003401:Creatine / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D005526:Food, Formulated; D006801:Humans; D008297:Male; D008875:Middle Aged; D008894:Milk Proteins; D018482:Muscle, Skeletal / Q000254:growth & development / Q000378:metabolism*; D014891:Weight Lifting / Q000502:physiology*; D000067816:Whey Proteins
D002364:Caseins; D004044:Dietary Proteins; D008894:Milk Proteins; D000067816:Whey Proteins; D003401:Creatine