*3.1. Blood Concentrations of Betaine and Coline*

Figure 3A illustrates the results of betaine concentrations in plasma before and after 2 weeks of betaine or placebo supplementation. A two-way repeated ANOVA with treatment and time indicated the interaction between two factors was significant (*p* < 0.05). The plasma betaine concentration in subjects in the placebo trial exhibited no significant differences before and after the supplementation. However, the plasma betaine concentration in the participants of betaine trial after 2 weeks of supplementation was significantly higher than before supplementation (6.53 ± 3.71 μg/mL vs. 2.04 ± 0.61 μg/mL, *p* < 0.05). Moreover, after 2 weeks of supplementation, the plasma betaine concentration was significantly higher for the betaine trial than the placebo trial (6.53 ± 3.71 μg/mL vs. 1.90 ± 0.23 μg/mL, *p* < 0.05). Figure 3B presents of choline concentrations in plasma before and after 2 weeks of betaine or placebo supplementation. A two-way repeated ANOVA with treatment and time indicated there is no interaction between two factors. The result shows that the supplementation strategy of present study can effectively enhance the betaine concentrations in plasma, rather than choline metabolism.
