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.
Unwashed? E.g., the mushrooms still have dirt, with the appropriate microorganisms, on them?
And how certain are you they are right that it is the active form?
Finally, it might be useful to your readers if you could estimate how much someone could get from a serving, and compare it to your recommended daily intake.
> Unwashed? E.g., the mushrooms still have dirt, with the appropriate microorganisms, on them?
I’d be surprised if microorganisms on the top of food could produce enough B12 to be measurable. But they could have been grown using organic fertilizer.
> And how certain are you they are right that it is the active form?
I should be certain based on their testing methods, but I’m not. You also have to consider inactive analogues interfering with active B12. They said they didn’t find much, but I’m not sure they tested for all of them of which there appears to be many. That’s why I think it’s necessary to feed multiple batches to people to see what effect it has on their B12 status.
> Finally, it might be useful to your readers if you could estimate how much someone could get from a serving, and compare it to your recommended daily intake.
1 kg of fresh weight would be about 18.5 cups of chanterelles, so it would take about 20 Cups of the golden chanterelles to reach the RDA using the 2.1 µg number.
Thanks! The problem with some vegans is they just say, “Mushrooms have B12!” Good to point out just how little they have, and we can’t be sure it is the active version.
February 21st, 2013 at 6:48 am
Unwashed? E.g., the mushrooms still have dirt, with the appropriate microorganisms, on them?
And how certain are you they are right that it is the active form?
Finally, it might be useful to your readers if you could estimate how much someone could get from a serving, and compare it to your recommended daily intake.
February 21st, 2013 at 11:10 am
Bertrand,
> Unwashed? E.g., the mushrooms still have dirt, with the appropriate microorganisms, on them?
I’d be surprised if microorganisms on the top of food could produce enough B12 to be measurable. But they could have been grown using organic fertilizer.
> And how certain are you they are right that it is the active form?
I should be certain based on their testing methods, but I’m not. You also have to consider inactive analogues interfering with active B12. They said they didn’t find much, but I’m not sure they tested for all of them of which there appears to be many. That’s why I think it’s necessary to feed multiple batches to people to see what effect it has on their B12 status.
> Finally, it might be useful to your readers if you could estimate how much someone could get from a serving, and compare it to your recommended daily intake.
1 kg of fresh weight would be about 18.5 cups of chanterelles, so it would take about 20 Cups of the golden chanterelles to reach the RDA using the 2.1 µg number.
February 24th, 2013 at 9:39 am
Thanks! The problem with some vegans is they just say, “Mushrooms have B12!” Good to point out just how little they have, and we can’t be sure it is the active version.