Carbohydrate ingestion augments creatine retention during creatine feeding in humans.
Level 3 - non-randomized controlled study
Controlled parallel-group experimental trial without explicit mention of randomization in the abstract
PubMed 8899067 · doi:10.1046/j.1365-201X.1996.528300000.x
What was done
Four groups of healthy male participants (total n = 22) were tested before, during, and after taking test solutions every 4 hours across two full days (20 g total daily creatine dose) and re-evaluated on day 3. Group A ingested 5 g creatine; groups B and C ingested 5 g creatine plus 93 g simple carbohydrates alongside a prescribed isoenergetic high-carbohydrate diet; group D received a creatine- and carbohydrate-free solution. Group C also completed 1 hour of cycling at 70% VO2 max each morning. Dietary intake was weighed and recorded, and blood and urine samples were measured for creatine and insulin kinetics.
What was found
On days 1 and 3, peak plasma creatine concentration, area under the plasma creatine concentration-time curve, and urinary creatine concentration were lower in carbohydrate-fed groups (B and C) compared to creatine alone (group A). Serum insulin concentrations were higher in groups B and C than in group A. No significant differences were observed between group B and group C. Exact numerical values were not reported in the abstract.
Why it matters
The study showed that co-ingesting simple carbohydrates with creatine increases circulating insulin and enhances whole-body creatine retention, without additional augmentation from pre-ingestion cycling exercise.
Limits
The sample size is very small (22 men across four groups). The abstract does not report randomization, exact numerical results, or variance. Findings apply only to healthy males consuming large amounts of simple carbohydrates (93 g per 5 g creatine dose), and direct intramuscular creatine concentrations were not measured in the abstract.
Cited by
- supports More than 75 grams of carbohydrates is required to augment creatine uptake into muscle.