Mykyta,

I cover it in the section on Nori above: https://staging.veganhealth.org/vitamin-b12/vitamin-b12-plant-foods/#nori

It definitely needs more testing before it can be considered a source of vitamin B12.

Luann,
I can’t explain why your B12 status is still adequate after 10 years of apparently not supplementing or eating fortified foods, but there’s no reason to think it’s because you eat morning dew. I would suggest you start making sure you meet our B12 recommendations before your B12 status begins to deteriorate.

“The foods with the highest betaine concentration (mg/100 g) were: wheat bran (1339), wheat germ (1241), spinach (645), pretzels (237), shrimp (218) and wheat bread (201).”
https://pubmed.ncbi.nlm.nih.gov/12730414/

Betaine is a stimulator of vitamin B12 overproduction in some bacteria
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC240058/

Kelsey,

> Why would studies conclude that foods like nori are good sources of Vitamin B12 if they aren’t?

I wondered the same thing, but they did. I provide their results in the table—they clearly show that nori didn’t improve vitamin B12 status as shown by uMMA increasing in response to both types of nori.

As we state in the article, “It cannot be emphasized enough that until a particular food, obtained from multiple regions, consistently improves vitamin B12 status (by lowering MMA levels) in humans, it should not be relied upon as a source of vitamin B12.”

They also say drying the nori did not affect B12 levels, unlike what you concluded.

Adam,

To keep things simple, I’ve changed this paragraph (which has a typo):

Given the number of vegans who’ve suffered from B12 deficiency, and that vegans have traditionally interest in organic foods in the U.S. and U.K., it’s safe to assume that organic foods normally don’t provide B12. Only until organic foods are chosen randomly from markets and grocery stores throughout the country (or world) and are consistently shown to decrease MMA levels will someone not be taking a considerable risk in relying on organic foods for B12.

To this:

It’s prudent not to assume that vegans who eat organic produce will be protected from B12 deficiency. Unless organic foods are consistently shown to decrease MMA levels, vegans should not rely on them for vitamin B12.

You said:

> I don’t think that you’d weaken your argument for vegans taking a B12 supplement in 2019 if you merely acknowledged that there is evidence that humans may have obtained active B12 from untreated water, fermented foods or unwashed organic plant foods in the past.

I’ve reviewed that evidence in this section, so in that respect, I am acknowledging it—but it’s not very persuasive. If I’m missing any (relatively direct) evidence, please let me know.