Fig. 3.

Violin plots of distribution in changes in serum (a) vitamin B₁₂, (b) holotranscobalamin, (c) homocysteine, (d) methylmalonic acid, (e) 4cB12 score, and (f) folate. *P-value < 0.05; **P-value < 0.01 for within-group changes comparing pre- and post-intervention, calculated by Wilcoxon signed-rank test. Across-group comparison were performed using Kruskal-Wallis test (χ² and P-value shown in lower left corner); when this test is significant, between-group differences were calculated using Dwass, Steel, Critchlow-Fligner procedure. Abbreviations: 4cB12 score, Four combined index of vitamin B₁₂ score