Molecular composition and kinetics of plasma phosphatidylcholine (PC) in response to choline supplementation. (A) PC molecular species grouped according to their content of different fatty acid residues in sn-position 2 (Sat. PC, C18:1-PC, C18:2-PC, C20:4-PC or C22:6-PC). White panels indicate the median PC composition prior to choline supplementation (visit [V] 2‒4, whereas grey panels are values after 84 d choline supplementation (V6-8). Striped panels indicate the molecular composition of PC synthesized de novo (D9-PC), whereas dotted panels indicate synthesis via methylation of phosphatidylethanolamine (D3-PC) [13,27]. (B) D9- and D3-enrichment of PC prior to and after choline supplementation. (C) The relative synthesis rates and kinetics of plasma PC sub-groups are identical prior to (visit [V] 2–4) and after (V6–8) 84 d choline supplementation. Data are medians and interquartile ranges of N = 10. Abbreviations: ** p < 0.01; *** p < 0.001.