Effect of age, diet and tissue type on PCr response to creatine supplementation

Creatine/phosphorylcreatine (PCr) responses to creatine supplementation may be modulated by age, diet and tissue, but studies assessing this possibility are lacking. Therefore, we aimed to determine whether the PCr responses vary as a function of age, diet, and tissue. Fifteen children, 17 omnivorous and 14 vegetarian adults, and 18 elderly participated in this study. Participants were given placebo and subsequently creatine (0.3 g•kg^-1•day^-1) for 7 days in a single-blind fashion. PCr was measured through phosphorus magnetic resonance spectroscopy (³¹P-MRS) in muscle and brain. Creatine supplementation increased muscle PCr in children (p<0.0003) and elderly (p<0.001), whereas the increase in omnivores did not reach statistical significant difference (p=0.3348). Elderly had greater PCr increases than children and omnivores (p<0.0001 for both), whereas children experienced greater PCr increases than omnivores (p=0.0022). In relation to diet, vegetarians (p<0.0001), but not omnivores, had significant increases in muscle PCr content. Brain PCr content was not affected by creatine supplementation in any group, and delta changes in brain PCr (-0.7 to +3.9%) were inferior than muscle PCr content (+10.3 to +27.6%; p<0.0001 for all comparisons). PCr responses to a standardized creatine protocol (0.3 g•kg^-1•day^-1 for 7 days) may be affected by age, diet and tissue. While creatine supplementation was able to increase muscle PCr in all groups, although to different extents, brain PCr was shown to be unresponsive overall. These findings demonstrate the need to tailor creatine protocols to optimise creatine/PCr accumulation both in muscle and in brain, enabling a better appreciation of the pleiotropic properties of creatine.

from Physiology via xlomafota13 on Inoreader http://ift.tt/2suzxxp
via IFTTT