Table 2.

Dietary intakes of vitamin B₁₂ in control and intervention groups

		Control group (n = 10)			Low-dose group (n = 10)			High-dose group (n = 10)			Among-group P-value#
		Median	P25	P75	Median	P25	P75	Median	P25	P75
Total dietary intakes of vitamin B12 including nori (µg/day)†	Pre	0.8	0.7	2.4	0.3	0.2	1.0	0.5	0.4	0.8	0.21
	Post	0.9	0.3	1.6	2.0 **	1.9	2.8	3.5 **	3.3	4.1	0.0003
Dietary intakes of vitamin B12 from foods other than nori (µg/day)	Pre	0.8	0.7	2.4	0.2	0.2	1.0	0.5	0.3	0.8	0.16
	Post	0.9	0.3	1.6	0.2	0.1	1.0	0.4	0.3	0.9	0.10

Data are presented as median, p25, p75. ^*P-value < 0.05; ^**P-value < 0.01 for within-group changes between post-intervention and pre-intervention calculated by Wilcoxon signed-rank test. ^# Among-group P-value comparison using Kruskal-Wallis test. ^† Total dietary intake of vitamin B₁₂ at post-intervention included intakes from both non-nori sources and study-prescribed nori provided for intervention groups (nori vitamin B₁₂ calculated using 38.6 µg/100 g assessed by our study)