Effect of roasted purple laver (nori) on vitamin B12 nutritional status of vegetarians: a dose-response trial

The study design is an open-label, parallel, dose-response randomized controlled trial. Thirty vegetarians were assigned to control (no nori), low-dose (5 g nori, aiming to provide 2.4 µg vitamin B12 per day), or high-dose (8 g nori, aiming to provide 4 µg vitamin B12 per day) groups.