A number of recent observations indicate that creatine supplementation might have a beneficial impact on glucoregulation (regulation of glucose metabolism). For example, supplementation with creatine in combination with carbohydrates can stimulate post-exercise muscle glycogen resynthesis [1]. Also, creatine intake in combination with carbohydrates resulted in greater muscle creatine concentration than creatine intake alone [2], which may be due to the fact that transport of glucose and creatine [3] in muscle cells are stimulated by insulin.
We found an interesting study that might provide some evidence that cycling on and off creatine might be a good idea. It is well established that muscle inactivity and training are effective stimuli to down- and upregulate muscle GLUT4 (Glucose transporter type 4 is the insulin-regulated glucose transporter) content [4]. Therefore, Eijnde, B. et al. [5] investigated the effect of creatine supplementation on muscle GLUT4 protein, creatine and glycogen concentration in healthy volunteers during 2 weeks of leg immobilization and 10 weeks of subsequent rehabilitation training. This study was the first to prove that creatine supplementation prevents the loss of GLUT4 protein during muscle disuse. Researchers also noted that muscle glycogen concentration were increased during the initial stages of the creatine supplementation. The above-average increase vanished after about 5 weeks of rehabilitation despite the continued use (Pic 1). This study also suggests that creatine supplementation in humans may increase insulin sensitivity by increasing muscle GLUT4 content.
Pic. 1 – During immobilization and rehabilitation, subjects ingested creatine monohydrate (▪) or placebo (□).
Since there is not much evidence whether to creatine cycle off or not, we think it’s always a good idea to let your body return to its normal state.
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References
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Robinson, Tristan M., et al. “Role of submaximal exercise in promoting creatine and glycogen accumulation in human skeletal muscle.” Journal of Applied Physiology 87.2 (1999): 598-604.
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Green, A. L., et al. “Carbohydrate ingestion augments skeletal muscle creatine accumulation during creatine supplementation in humans.” American Journal of Physiology-Endocrinology And Metabolism 271.5 (1996): E821-E826.
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Odoom, Joseph E., Graham J. Kemp, and George K. Radda. “The regulation of total creatine content in a myoblast cell line.” Molecular and cellular biochemistry 158.2 (1996): 179-188.
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Houmard, JOSEPH A., et al. “Effect of reduced training and training cessation on insulin action and muscle GLUT-4.” Journal of Applied Physiology 81.3 (1996): 1162-1168.
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Eijnde, B., et al. “Effect of oral kreatine supplementation on human muscle GLUT4 protein content after immobilization.” Diabetes 50.1 (2001): 18-23.
