Seaweed | The Nutrition Source | Harvard T.H. Chan School of Public Health.
Does seaweed contain vitamin B12?*
Not afaik. Vegemite does contain B vitamins, but not B12.
I have a vegan friend who won’t eat honey due to the moral issues of bee farming.
I know anecdote is not the singular of data, but we’re in MPSIMS, so I will say: if you could OD on greens, I’d be dead by now. I have, and have had for a number of years now, a sweet potato patch, which produces ridiculous, and I do mean RIDICULOUS, quantities of sweet potato leaves. I scarf them up regularly in huge quantity. I also grow and regularly eat some kind of spinach (I dunno specifically what it is, a friend gave me the cutting), and I have so much basil that I eat it as a sandwich green.
If I die of a greens overdose, I’ll let y’all know.
My sister in law od’d on carrots, and turned orange briefly. But as others have said, the orange color is plenty of warning, and she cut back on the carrots and was fine.
I’ve never heard of a vegan worrying about overdosing on vitamins. And i know several vegans and talk with them about food and nutrition.
Re Seaweed and B12 - it does seem that you have to be very picky with your seaweed. But this paper says:
A survey of naturally occurring and high Vitamin B12-containing plant-derived food sources showed that nori, which is formed into a sheet and dried, is the most suitable Vitamin B12 source for vegetarians presently available. Consumption of approximately 4 g of dried purple laver (Vitamin B12 content: 77.6 μg /100 g dry weight) supplies the RDA of 2.4 μg/day. In Japan, several sheets of nori (9 × 3 cm2; approximately 0.3 g each) are often served for breakfast. A large amount of nori can be consumed as certain forms of sushi (vinegared rice rolled in nori).
Fermented beans and (some) mushrooms also get a degree of approval in that paper.
I don’t know if you know this US Department of Agriculture nutritional information website: https://fdc.nal.usda.gov/
It can be very detailed - you can get lost in there for days.
This is the entry for Marmite (yeasty stuff). Looks like 15g or so a day would keep you good for B12.
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ETA - just noticed that it says that Marmite is enriched with B12. Huh.
Brewer’s yeast does not appear to have been enriched. 20 g of that per day would work, but that sounds like tough sledding.
Yes, interesting vegemite contains maybe a trace of B12, but Marmite has a decent amount.
We need about 2.5 mcg, and a serving of Marmite has just under 2mcg, so two slices of buttered toast with Marmite would pretty much fill the bill.
Great cites here, thanks!