Effect of Creatine Monohydrate Supplementation on Macro- and Microvascular Endothelial Function in Older Adults: A Pilot Study

Background/Objectives: A pilot study was conducted to investigate the effect of four weeks of creatine monohydrate (CrM) on vascular endothelial function in older adults. Methods: In a double-blind, randomized crossover trial, twelve sedentary, healthy older adults were allocated to either the CrM or placebo (PL) group for four weeks, at a dose of 4 x 5 g/day for 5 days, followed by 1 x 5 g/day for 23 days. Macrovascular function (flow-mediated dilation [FMD%], normalized FMD%, brachial-ankle pulse wave velocity [baPWV], pulse wave analysis [PWA]), microvascular function (microvascular reperfusion rate [% StO(2)/sec]), and biomarkers of vascular function (tetrahydrobiopterin [BH4], malondialdehyde [MDA], oxidized low-density lipoprotein [oxLDL], glucose, lipids) were assessed pre- and post-supplementation with a four-week washout period. Results: CrM significantly increased FMD% (pre-CrM, 7.68 +/- 2.25%; post-CrM, 8.9 +/- 1.99%; p < 0.005), and normalized FMD% (pre-CrM, 2.57 x 10(-4) +/- 1.03 x 10(-4)%/AUC(SR); post-CrM, 3.42 x 10(-4) +/- 1.69 x 10(-4)%/AUC(SR); p < 0.05), compared to PL. Microvascular reperfusion rates increased following CrM (pre-CrM, 2.29 +/- 1.42%/sec; post-CrM, 3.71 +/- 1.44%/sec; p < 0.05), with no change following PL. A significant reduction in fasting glucose (pre-CrM, 103.64 +/- 6.28; post-CrM, 99 +/- 4.9 mg/dL; p < 0.05) and triglycerides (pre-CrM, 99.82 +/- 35.35; post-CrM, 83.82 +/- 37.65 mg/dL; p < 0.05) was observed following CrM. No significant differences were observed for any other outcome. Conclusions: These pilot data indicate that four weeks of CrM supplementation resulted in favorable effects on several indices of vascular function in older adults.