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 PCr responses vary as a function of age, diet, and tissue. Fifteen children, 17 omnivorous and 14 vegetarian adults, and 18 elderly individuals ("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 statistically 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 to those in 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. Where...
Source: Journal of Applied Physiology - Category: Physiology Authors: Tags: RESEARCH ARTICLE Source Type: research