B12 in Mushrooms
A 2012 study from the Watanabe group (1) was released today on PubMed. I have added the following to B12 in Tempeh, Seaweeds, Organic Produce, and Other Plant Foods.
They found what they thought was active vitamin B12 in the following mushrooms (per 100 g of dry weight):
- 2.9 – 3.9 µg in black trumpet (Craterellus cornucopioides)
- 1.3 – 2.1 µg in golden chanterelle (Cantharellus cibarius)
- 1.3 µg in parasol (Macrolepiota procera)
- .3 – .4 µg in porcini (Boletus spp.)
- .2 µg in oyster (Pleurotus ostreatus)
- .1 µg in black morels (Morchella conica)
The authors noted that 100 g of dry weight was the equivalent of about 1 kg of fresh mushrooms. They said that a moderate intake of black trumpet or golden chanterelle “may contribute slightly to the prevention of severe B12 deficiency in vegetarians.” They did not know why the mushrooms contained B12 and also did not test the mushrooms in humans to determine their ability to lower methylmalonic acid (MMA) levels.
As always, I will add a word of caution that vegans should not rely on any plant food for vitamin B12 until a number of batches have consistently lowered MMA levels in humans.