Effect of age, diet, and tissue type on PCr response to creatine supplementation.
Level 3 - non-randomized controlled study
Non-randomized sequential intervention study comparing distinct age and dietary cohorts
PubMed 28572496 · doi:10.1152/japplphysiol.00248.2017
What was done
Researchers evaluated how age, habitual diet, and tissue type affect phosphorylcreatine (PCr) accumulation following creatine supplementation. Sixty-four participants (15 children, 17 omnivorous adults, 14 vegetarian adults, and 18 elderly individuals) completed a single-blind protocol where they received a placebo followed sequentially by creatine (0.3 g·kg⁻¹·day⁻¹) for 7 days. Changes in muscle and brain PCr content were quantified using phosphorus magnetic resonance spectroscopy (³¹P-MRS).
What was found
Creatine loading increased muscle PCr in children (P < 0.0003), elderly participants (P < 0.001), and vegetarians (P < 0.0001), while the increase in adult omnivores did not reach statistical significance (P = 0.3348). Elderly participants had greater muscle PCr increases than children and omnivores (P < 0.0001 for both), and children had greater increases than omnivores (P = 0.0022). Muscle PCr increases ranged between +10.3% and +27.6%. In contrast, brain PCr content was not affected by creatine supplementation in any group, with delta changes ranging from -0.7% to +3.9%, which were significantly lower than muscle changes (P < 0.0001 for all comparisons).
Why it matters
Standard short-term creatine loading protocols increase muscle PCr primarily in populations with lower baseline stores (the elderly and vegetarians) but fail to alter brain PCr. Creatine protocols cannot follow a single universal standard for all tissues and demographics.
Limits
The study used a sequential, non-randomized before-and-after design with a single-blind approach. Subgroup sample sizes were small (14–18 participants per cohort). The intervention lasted only 7 days, which may be insufficient to observe changes in brain tissue.
Cited by
- supports A neuroimaging study from Brazil showed that vegans and omnivores have identical baseline brain creatine stores despite vegans having significantly lower skeletal muscle creatine content.