Vitamin B12 (cobalamin) is an absolute requirement for human life. It powers your nervous system, forms red blood cells, synthesizes DNA, and keeps your brain functioning at its peak. Yet, B12 deficiency is shockingly common. So, when trying to fix a deficiency or maintain healthy levels, we need to know a thing or two about the “energy vitamin’s” sources.
Here's how the main sources actually stack up
Nutritional Yeast: Fortified, Not Grown
Nutritional yeast has a reputation as a "natural" vegan B12 source, but the yeast itself doesn't produce B12. Manufacturers spray or soak the yeast flakes in synthetic cyanocobalamin after fermentation - the same compound used in most standard supplements. It may be a legitimate way to prevent deficiency, but nutritionally, a spoonful of nutritional yeast is closer to taking a supplement than to eating a whole natural food rich in the vitamin.
Spirulina's Pseudo-B12 Problem
Spirulina is often marketed as a plant-source B12, but lab analysis tells a different story. Most of the "B12" spirulina contains is actually pseudovitamin B12 - a look-alike compound where the lower ligand of the cobalamin molecule is swapped for adenine instead of the structure human enzymes recognize. We need more research to settle these things - but it seems that the pseudovitamin does not work as well as real vitamin B12 in humans, and may even block real B12 absorption, even though it may also serve other beneficial functions such as potentially being a prebiotic.
Other Seaweeds’ Real B12
The B12 in Ulva, Chlorella and Nori may be the real deal and that is fantastic for those that want a plant-based alternative source. However, the amounts will be much lower than in, for example, beef liver. The amounts will also vary by batch, and the plants may contain pseudovitamin B12 as well.
The Kimchi Question
Fermented vegetables like kimchi and sauerkraut may contain B12 since some bacterial strains in some batches will produce it. In practice, the strains typically involved in vegetable fermentation aren't reliable cobalamin producers, and B12 content varies wildly by batch, region, and fermentation method - nowhere near consistent enough to be relied on over time for your B12 levels, even if it can supply some at times.
Supplemental B12: Cyanocobalamin vs. Methylcobalamin
Most B12 supplements use one of two forms:
- Cyanocobalamin - the more synthetic, cheapest form, bound to a cyanide molecule your body has to cleave off before use.
- Methylcobalamin - one of the two "coenzyme" forms your body actually uses directly, the more natural option.
Methylcobalamin is a step closer to what's biologically active, but isolated in a pill, it's still stripped of the food matrix it would normally travel with: the fats, proteins, and cofactors (like folate and B6) that help your body actually put B12 to work. An isolated vitamin, however "bioidentical" it sounds, is not the same as the vitamin still embedded in food.
Why Liver Is the Ultimate Source
In 1926, physicians George Minot and William Murphy found that feeding pernicious anemia patients large daily amounts of raw liver reversed a disease that had been considered fatal. This work won the 1934 Nobel Prize in Physiology or Medicine, more than two decades before anyone had even isolated vitamin B12 as a molecule. Liver was the cure before science knew why.
That's because liver delivers B12 the way nature packages it: bound to animal protein, alongside the cofactors your body needs to actually use it (B6, folate, and iron among them) with no pseudovitamins potentially competing for absorption and nothing synthetic to metabolize first. It's simply one of the most concentrated, complete, bioavailable source of B12 that exists in nature.
This is exactly the logic behind our Primal Hunt beef liver supplement: freeze-dried, whole-food liver from properly raised animals. Not a pseudovitamin, not a synthetic, not a low dose. Just the same goodness our ancestors knew so well to cherish. Each daily dose actually gives you as much as 464% of the daily recommended intake in Norway.
The Bottom Line
Not all B12 is created equal. Some is inactive (spirulina). Some is added after the fact (nutritional yeast). Some is genuinely promising but with lower doses (Ulva, Kimchi). Some is synthetic and isolated (standard supplements). And some (liver) is the original, whole-food source that's been quietly doing the job since long before anyone even knew the vitamin's name.
If you're not eating liver weekly, a freeze-dried whole-food liver supplement is the closest thing to closing that gap the way nature intended.
Not medical advice. This article is for general educational purposes only and isn't intended to diagnose, treat, cure, or prevent any disease. If you have concerns about a deficiency or an underlying health condition, please speak with your doctor before changing your diet or supplement routine.
1 comment
I appreciate how much simpler it is to have a dedicated B12 supplement routine in terms of getting all of your levels on point. As long as you’re consistent it’s so much easier to track. For me, the less guesswork the better.