Nutrition
Are fermented foods enough as a source of vitamin B12?
Short answer
Unfortunately no — that is one of the more common myths. Fermentation is genuinely good for gut flora, but the bacteria that produce B12 in pickled foods usually do not make a form the human body can absorb. Rather than relying on cabbage or cucumbers, it is better to use a supplement or fortified foods — plant milks, breakfast cereals or nutritional yeast with added B12.
NIH lists reliable B12 sources as a supplement and fortified foods — not pickles. The bacteria in sauerkraut do not make B12 in doses you can build a diet on.
“Sauerkraut heals B12” is a popular wellness myth. Safe practice: a regular supplement or fortified foods such as plant drinks, breakfast cereals or nutritional yeast.