B12 Status of Whole Foods Vegans Consuming Nori and Mushrooms
In a 2014 study from Germany (1), a group of 10 whole foods vegans, who did not take supplements, were found to have methylmalonic acid (MMA) levels of almost 400 nmol/l. MMA is the most specific way to measure vitamin B12 status, with healthy levels being 270 nmol/l or less.
A second group of vegans who supplemented – it’s not clear with how much but it seems to have been at least 2 doses of 1,000 µg/week of B12 on average – had MMA levels of just above 200 nmol/l.
The whole foods-only vegans were given a minimum of 12 g/week of nori and 15 g/week of sun dried mushrooms, which the researchers calculated to contain an average of 3.1 µg/day of vitamin B12; the RDA is 2.4 µg. Their MMA levels were measured every 2 months for 8 months and they did not dip much below 350 nmol/l.
The vegans who took supplements were given more B12 than normal (though it’s not clear how much), and their MMA levels steadily decreased to about 150 nmol/l at 6 months, but then back up to 200 nmol/l at 8 months.
This research indicates that at the amounts given, nori and sun dried mushrooms do not improve vitamin B12 status.
I have updated the VeganHealth.org article B12 in Plant Foods with this information.
1. Schwarz J, Dschietzig T, Schwarz J, Dura A, Nelle E, Watanabe F, Wintgens KF, Reich M, Armbruster FP. The influence of a whole food vegan diet with Nori algae and wild mushrooms on selected blood parameters. Clin Lab. 2014;60(12):2039-50. | link