Fig. 1

The mean dietary intake of creatine across ten NHANES rounds (1999–2000 to 2017–18) in three age-specific categories; the amounts are presented in grams (Panel A) and milligrams per kilogram of body weight (Panel B), with error bars indicate 95% confidence interval. Lines with circle ends indicate a significant difference between marked NHANES rounds at P < 0.05. Dashed lines are trendlines for each age category, with Kendall’s tau-b coefficient shown in case of significant trend detected (P < 0.05)