Where does B12 come from?
Besvaret 27. oktober 2026
Yes, B12 is made by bacteria, not by the animals themselves. But animals are not just a channel for supplements. In ruminants such as cows, microbes in the rumen make B12 themselves, as long as the feed contains enough cobalt. Humans and most animals with a single stomach need ready-made B12 from their food.
B12 has been added to animal feed for decades, according to the EU food safety authority EFSA. Its assessment rests on data from the vitamin makers who applied for approval. Dairy cows are recommended a cobalt supplement so their rumen bacteria make more B12. A British commentary notes that pork today has about a third less B12 than in the early 1990s, most likely because pigs are no longer fed animal offal.
So the animal step can be skipped: the Danish food authority advises vegans to take 4 µg of B12 a day.
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- Gennemgang fra Universidad de León, 2020Samler mange studier · OversigtsartikelRelationship between Vitamin B12 and Cobalt Metabolism in Domestic Ruminant: An Update
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