Most plant foods don’t contain any vitamin B12 at all — but NIH specifically calls out one exception: fortified nutritional yeast. Here’s how much B12 you’re actually getting per serving, and whether the other fortified vitamins on the label are something to watch.
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This article is for informational purposes only and is not medical advice. Talk to your doctor before starting any new supplement or making major changes to how you get key nutrients.
Why Nutritional Yeast Is Considered a Real B12 Source (Not Just a Cheese Substitute)
Vitamin B12 is one of the few nutrients that plant foods genuinely lack. It’s made by bacteria, not plants, which is why B12 deficiency is a real concern for people eating fully plant-based diets.
NIH’s Office of Dietary Supplements is direct about the one notable exception: “Plant foods do not naturally contain vitamin B12. However, fortified breakfast cereals and fortified nutritional yeasts are readily available sources of vitamin B12 that have high bioavailability.” That’s a meaningful distinction — it’s not nutritional yeast itself that supplies the B12, it’s the fact that manufacturers add it during fortification. A non-fortified nutritional yeast product (some brands sell these, marketed as more “natural”) won’t have any meaningful B12 at all, because the yeast itself doesn’t produce it.
So how much B12 are you actually getting per serving?
How Much B12 (and Other B Vitamins) Is Actually in a Serving
A two-tablespoon serving of Bragg’s Premium Nutritional Yeast Seasoning provides 15 micrograms of vitamin B12 — about 630 percent of the daily value, and roughly six times the RDA of 2.4 micrograms a day for adults. The same serving also delivers 6.2mg of thiamin (B1), 6.3mg of riboflavin (B2), 35mg of niacin (B3), 7.2mg of vitamin B6, and 353mcg DFE of folate (B9), according to the manufacturer’s own nutrition label.
The same dose-dependent absorption pattern that applies to B12 supplements applies here too: NIH data shows absorption is around 50 percent at doses under 1 to 2 micrograms, then drops off sharply as the dose increases, because intrinsic factor — the protein that shuttles B12 through the gut efficiently — can only handle so much at once. Fifteen micrograms sits well above that low-dose range, so the absorption rate is very likely lower than 50 percent. NIH’s data doesn’t give an exact figure at that specific dose, so it’s not possible to say precisely how much of it you’re absorbing. What is clear is that the RDA is so small (2.4mcg) that even a reduced absorption rate at 15 micrograms should still comfortably cover a day’s requirement.
The B12 story looks solid. But two other nutrients on that label are worth a second look.
Where It Gets Interesting: Niacin Lines Up With the Safety Limit
That same two-tablespoon serving contains 35mg of niacin. NIH sets the tolerable upper intake level (UL) for supplemental niacin at 35mg a day for adults — meaning this one serving lines up exactly with that ceiling.
Here’s where it gets genuinely unclear: NIH’s guidance says no adverse effects have been reported from niacin that occurs naturally in food, and that the UL applies specifically to niacin taken as a supplement. This product’s niacin isn’t naturally occurring — it’s added during fortification. NIH’s fact sheet doesn’t spell out which category fortified-food niacin falls into, so it’s not accurate to say definitively whether this counts toward the supplement-style UL or gets treated like food-based niacin. What’s worth knowing regardless: if you’re the type of person who sprinkles this on popcorn, then pasta, then a salad in the same day, those 35mg servings add up fast, and the form of niacin used (nicotinic acid versus nicotinamide, which behave differently) isn’t specified on the label.
Vitamin B6 tells a very different story.
Vitamin B6 Is Nowhere Close to Being a Problem Here
A two-tablespoon serving provides 7.2mg of vitamin B6 — a small fraction of the 100mg a day tolerable upper intake level that NIH sets for adults. That’s worth putting in context: some B-complex supplement pills pack a full 100mg of B6 into a single daily dose, landing right at that same safety ceiling. This nutritional yeast seasoning delivers about 7 percent of that amount per serving, even after accounting for multiple servings across a day, the margin here is wide.
That gap is a useful illustration of the difference between food-based fortification and megadose supplement pills: both technically deliver vitamin B6, but the amounts involved aren’t remotely comparable.
The Bottom Line
Fortified nutritional yeast — like Bragg’s Premium Nutritional Yeast Seasoning — is one of the few plant-based foods NIH specifically recognizes as a genuine, high-bioavailability source of B12, not just a cheese-flavored seasoning. A single serving delivers far more B12 than the daily RDA, even accounting for reduced absorption at higher doses. The niacin content happens to land exactly at the official upper limit, though whether that limit even applies to fortified food niacin isn’t something NIH’s fact sheet clarifies — worth knowing if you use this liberally throughout the day. Vitamin B6, on the other hand, isn’t close to a concern at this dose.
Two tablespoons of nutritional yeast won’t cure a deficiency on their own — but as far as plant-based B12 sources go, this one has the NIH’s own fact sheet behind it.