CARBOHYDRATE INGESTION AUGMENTS SKELETAL-MUSCLE CREATINE ACCUMULATIONDURING CREATINE SUPPLEMENTATION IN HUMANS

This study investigated the effect of carbohydrate (CHO) ingestion on skeletal muscle creatine (Cr) accumulation during Cr supplementation i n humans. Muscle biopsy, urine, and plasma samples were obtained from 24 males before and after ingesting 5 g Cr in solution (group A) or 5 g Cr followed, 30 min later, by 93 g simple CHO in solution (group B) four times each day for 5 days. Supplementation resulted in an increas e in muscle phosphocreatine (PCr), Cr, and total creatine (TCr; sum of PCr and Cr) concentration in groups A and B, but the increase in TCr in group B was 60% greater than in group A (P < 0.01). There was also a corresponding decrease in urinary Cr excretion in group B (P < 0.001 ). Creatine supplementation had no effect on serum insulin concentrati on, but Cr and CHO ingestion dramatically elevated insulin concentrati on (P < 0.001). These findings demonstrate that CHO ingestion substant ially augments muscle Cr accumulation during Cr feeding in humans, whi ch appears to be insulin mediated.