Carbohydrate ingestion augments creatine retention during creatine feeding in humans.
Blood and urine samples were obtained from four groups of healthy male subjects (A-D, total n = 22) before, during and after ingesting the following: group A, 5 g of creatine in solution; groups B and C, 5 g of creatine and 93 g of simple carbohydrate in solution: group D, a creatine- and carbohydrate-free solution. Subjects ingested the above preparations every 4 h for the remainder of the day and throughout the next day (total daily creatine dose = 20 g), and reported back to the laboratory on day 3 to undergo the same procedures as on day 1. Throughout this time, subjects weighed and recorded all dietary intake, and those in groups B and C ingested a prescribed isoenergetic high carbohydrate diet. Subjects in group C also performed 1 h of cycling exercise at 70% of their maximal oxygen consumption on the morning of each day. On both days 1 and 3, peak plasma creatine concentration, the area under the plasma creatine concentration/time curve and urinary creatine concentration were lower in groups B and C than in group A. Conversely, serum insulin concentration was higher in groups B and C than in A. No differences were evident when comparing groups B and C. These data suggest carbohydrate ingestion augmented creatine retention during creatine feeding and that creatine retention was not further increased when exercise was performed prior to ingestion.
Department of Physiology and Pharmacology, University Medical School, Queen's Medical Centre, Nottingham, UK.
A L
AL
Green
E J
EJ
Simpson
J J
JJ
Littlewood
I A
IA
Macdonald
P L
PL
Greenhaff
D000328:Adult; D003401:Creatine / Q000378:metabolism*; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007328:Insulin / Q000378:metabolism; D008297:Male
D004040:Dietary Carbohydrates; D007328:Insulin; D003401:Creatine