FIGURE 3.

Mean (±SEM) isotopic enrichment of plasma and urinary choline metabolites [labeled metabolite/(labeled + unlabeled metabolite)] grouped by choline intake (A; n = 10–12 per choline intake group) or 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T genotype (B; n = 7 with 677CC; n = 13 with 677TT) or both (C; n = 4–8 per group) at week 12 in folate-compromised Mexican American men who consumed 15% of their total choline intake as d9-choline from weeks 10 to 12. Data were analyzed by 2-factor ANOVA; P < 0.05 was considered significant. For the enrichment ratio of d9-betaine to d9-phosphatidylcholine (d9-PtdCho), an interaction between MTHFR C677T and choline intake was detected (P = 0.03; C). Thus, the data are presented after stratification by MTHFR C677T genotype. DMG, dimethylglycine.