Creatine supplementation affects glucose homeostasis but not insulin secretion in humans.
OBJECTIVE
In this study, it was investigated whether the glucose homeostasis is affected by dietary creatine supplementation. For this purpose, the plasma glucose concentration and the plasma insulin response to an oral glucose load were measured in creatine-supplemented vegetarians.


METHODS
The subjects were supplemented with either 5 g of creatine monohydrate (creatine-treated group, CREAT) or 5 g of maltodextrin (control group, CON) per day for 42 days. On days 0 and 43, blood samples were collected before as well as 10, 20, and 30 min following an oral glucose load and analyzed for plasma creatine, insulin, and glucose levels.


RESULTS
Creatine supplementation resulted in an increase in plasma creatine (CREAT 92.7 +/- 14.6 micro M vs. CON 31.2 +/- 3.2 micro M; p = 0.001). There was a trend (p = 0.07) towards elevated fasting plasma glucose levels following creatine supplementation, while the plasma glucose response to the glucose load was enhanced (CREAT 168.2 +/- 5.3 mM. min vs. CON 129.6 +/- 14.7 mM.min; p = 0.05). There was no difference observed in the plasma insulin response to the glucose load between the groups.


CONCLUSIONS
This study shows that creatine supplementation may result in abnormalities in glucose homeostasis in the absence of changes in insulin secretion.
Rooney
Kieron B
KB
Human Nutrition Unit, School of Molecular and Microbial Biosciences, University of Sydney, Australia. kroo436@mail.usyd.edu.au
Bryson
Janet M
JM
Digney
Alison L
AL
Rae
Caroline D
CD
Thompson
Campbell H
CH
D001786:Blood Glucose / Q000187:drug effects* / Q000378:metabolism*; D001835:Body Weight / Q000187:drug effects; D003401:Creatine / Q000494:pharmacology*; D014676:Diet, Vegetarian; D019587:Dietary Supplements; D005260:Female; D006706:Homeostasis / Q000187:drug effects*; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D008297:Male; D012016:Reference Values; D013997:Time Factors
D001786:Blood Glucose; D007328:Insulin; D003401:Creatine