They Changed the Light and the Algae Started Making the Vitamin B12 a Human Can Actually Use
Ordinary spirulina is full of a B12 lookalike the body cannot use, which is why it has never been the answer for anyone avoiding animal food. Adjusting the light it grows under produced 1.64 micrograms of the active form per 100 grams.
Outspoken Digest Nutrition Desk
Monday, August 31, 2026/3 min read
Spirulina has been sold as a vitamin B12 source for decades and it has never really been one. Researchers have now grown a version that is, by changing the light.
The resulting biomass carried 1.64 micrograms of biologically active B12 per 100 grams. Beef, for comparison, carries somewhere between 0.7 and 1.5 micrograms per 100 grams. The work was led by Dr Asaf Tzachor at Reichman University with collaborators in Iceland, Denmark and Austria, and published in Discover Food.
The problem this solves is older than the product
Conventional spirulina is full of pseudovitamin B12.
It is a structural near copy of the real thing. It shows up as B12 in the crude tests that food labels have historically relied on, which is how the health claim got established. Human beings cannot use it. Worse, there has long been a concern that it may compete with real B12 for absorption, meaning a supplement marketed as a fix could in principle work against the problem.
That is not a small footnote about one algae. B12 deficiency is the single most predictable nutritional failure of a diet with no animal products in it, because the vitamin is made by bacteria and reaches humans almost entirely through animals that have concentrated it. Every credible vegan nutrition guide for thirty years has said the same thing: this one is not optional and it does not come from plants.
What the researchers actually did
Changed the light environment the algae grew in, and the metabolism changed with it.
That is a more interesting result than a bigger number would have been, because it says the capacity was there and the growing conditions were suppressing it. Commercial spirulina is grown for yield in open ponds and raceways under whatever the sun provides. Controlling the spectrum is a production change rather than a genetic one.
The team describe the biomass as carbon neutral, and that claim deserves the same scepticism as any other carbon claim about a novel food: it depends entirely on where the energy for those lights comes from, and controlled spectrum cultivation is not a low energy process.
What has not been shown
That anyone's B12 status improves by eating it.
This is measurement of a compound in a food, not a feeding trial. The chain from here to a useful product has several links that have all broken before for other foods: the active form has to survive processing and storage, it has to be absorbed by a human gut, absorption has to be enough to shift blood markers, and the whole thing has to be reproducible at commercial scale rather than in a controlled vessel.
None of those are reasons to dismiss the finding. They are the reasons it is a first step, and the release itself notes this is the first time biologically active B12 has been identified in spirulina.
The awkward part
A B12 supplement costs almost nothing and works.
Cyanocobalamin has been cheap, stable, effective and vegan for a very long time. So the honest question about engineered spirulina is not whether it beats deficiency, it is whether it beats a tablet, and on cost it will not.
Where it could matter is in places where supplement supply chains are unreliable but local cultivation is possible, and in the general project of making plant based diets nutritionally complete from food rather than from pills. That is a real goal and this is real progress toward it. It is not news that changes what anyone should do this week.
What to do meanwhile
If you avoid animal products, take B12. Do not rely on any algae, seaweed, fermented food or unfortified plant product, whatever the label says, until a human trial says otherwise for that specific product.
The wider lesson is the one that keeps coming back on this desk: a nutrient present in a food is not a nutrient in a person. We made the same point about what the label does and does not tell you in plant protein versus animal protein, and about a category being described by what it is not in yesterday's survey of plant based products.
Published in The Outspoken Digest
Editorial desk
Outspoken Digest Nutrition DeskDiet, food science and the evidence behind claims about what we eat.
Newsletter
The Digest, in your inbox
One edition, sent when it is ready. No noise, and your address is never passed on.
Read Next
More Nutrition →
Every One of 212 Plant Based Products Tested in Britain Contained a Fungal Toxin
Aug 30, 2026/4 min read
Wine Drinkers Died Less Often in a 340,000 Person Study, and the Most Likely Explanation Is Dinner
Aug 28, 2026/4 min read
The Mice Kept Eating Less and Put the Weight Back On Anyway. That Is the Interesting Part.
Aug 25, 2026/4 min read
Tahini Is One Ingredient, and the Jar in Your Cupboard Is Probably the Wrong One
Aug 21, 2026/3 min read