This is the first study describing temporal trends in dietary creatine intake at the populational level to the authors’ knowledge. We found that creatine consumption fluctuates among U.S. children and adults during the past two decades, with the absolute intake tended to decline in infants, children, and adolescents while the relative amount of creatine consumed kept relatively steady during this monitoring period. The highest intake of creatine among adults was reported during the NHANES 2011–12 round (0.87 g/day), yet the amount remains below recommended levels of 1.0 g/day for an average adult [2]. Besides, it appears that 68.6% of adults (35,983 out of 52,487 individuals) consumed less than one gram of creatine daily, indicating a relatively high proportion of inadequate dietary creatine intake in this age group. Such a prediction for non-adults remains unattainable since no dietary creatine requirements or recommendations for younger age are available at the moment.
During the 20-year period, dietary creatine intake decreased in U.S. infants, children, and adolescents. Our data also suggest that for each additional round of NHANES completed from 1999 to 2000 onwards, the expected amount of creatine consumed significantly decreased for 2.08 mg in infants, and for 3.22 mg in children and adolescents. Although this amount appears small, the trend might be of high clinical relevance owing to the fundamental role that dietary creatine plays in normal growth and health, with lower creatine availability appears to jeopardize young brain development in preclinical and clinical nutrition [7]. Whether dietary creatine shortfall affects children’s well-being currently remains unaddressed at the community-wide level. The possible factor contributing to the reduction of dietary creatine intake in youth might include lower meat consumption across U.S. households [8]. Since lean red meat, fish, and poultry are the primary dietary sources of creatine, eating less meat is likely accompanied by reduced dietary creatine exposure. This perhaps justifies backing diets rich in creatine-containing foods and low-dose supplementation or food fortification with creatine to optimize its dietary load in the general public [4]. Adding creatine to a regular diet normalizes creatine utilization and brain function in children with inborn errors of creatine metabolism [9]. Nevertheless, prospective studies must establish adequate dietary allowances for creatine to meet healthy persons’ needs across various life-stage groups.
The limitations of our study include the following: (a) the use of 24-h recall method to measure food consumption of NHANES participants; (b) implementing the identical amount of creatine across all creatine-containing meat-based foods while the creatine content can vary greatly across animal protein subgroups [3]; (c) not including non-meat creatine foods (e.g., milk and milk products) and nutritional supplements in computing daily creatine intake although their contribution to daily creatine intake appears relatively negligible [3]; (d) an inability to include pre-1999 NHANES data for more comprehensive comparisons, and (e) not accounting for endogenous creatine synthesis that contributes to total creatine turnover. Still, the mean daily intake of creatine in the current study appears similar to other reports using the NHANES database published recently [3,4,5]; a minor variation between studies may reflect different techniques employed to handle fragmented dietary entries and missing data, and non-identical sample composition and scaling. A few studies to date have combined or compared creatine intake data from several NHANES rounds across multiple years by maximizing sample size, which is the main advantage of current trial.