Protein- and carbohydrate-induced augmentation of whole body creatine retention in humans.
This study investigated the effect of creatine supplementation in conjunction with protein and/or carbohydrate (CHO) ingestion on plasma creatine and serum insulin concentrations and whole body creatine retention. Twelve men consumed 4 x 5 g of creatine on four occasions in combination with 1) 5 g of CHO, 2) 50 g of protein and 47 g of CHO, 3) 96 g of CHO, or 4) 50 g of CHO. The increase in serum insulin was no different when the protein-CHO and high-CHO treatments were compared, but both were greater than the response recorded for the low-CHO treatment (both P < 0.05). As a consequence, body creatine retention was augmented by approximately 25% for protein-CHO and high-CHO treatments compared with placebo treatment. The areas under creatine- and insulin-time curves were related during the first oral challenge (r = -0.920, P < 0.05) but not after the fourth (r = -0.342). It is concluded, first, that the ingestion of creatine in conjunction with approximately 50 g of protein and CHO is as effective at potentiating insulin release and creatine retention as ingesting creatine in combination with almost 100 g of CHO. Second, the stimulatory effect of insulin on creatine disposal was diminished within the initial 24 h of supplementation.
Steenge
G R
GR
School of Biomedical Sciences, University Medical School, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom.
Simpson
E J
EJ
Greenhaff
P L
PL
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D003401:Creatine / Q000097:blood / Q000378:metabolism* / Q000652:urine; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D004044:Dietary Proteins / Q000494:pharmacology*; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D007328:Insulin; D003401:Creatine