Plasma riboflavin and flavin mononucleotide
Among control group participants (taking a supplement without riboflavin), as expected, plasma riboflavin was similar at preconception baseline and 1 month after supplementation commencement, then decreased by 0.24 (0.11 to 0.38, Plasma flavin mononucleotide, a marker of riboflavin sufficiency, in the control group showed a similar longitudinal pattern to plasma riboflavin but increased by 0.21 (0.11 to 0.31, 