Understanding B12: How much B12 is in kimchi?

November 4, 2025 •

3 min read

Despite kimchi's probiotic benefits, most standard commercial and homemade kimchi contains negligible to undetectable amounts of vitamin B12. The question of how much B12 is in kimchi? is often asked by those seeking plant-based sources, but the nutritional reality is more complex.

Quick Summary

Standard kimchi provides minimal or no vitamin B12, challenging the common belief that fermented foods are a reliable source. Its B12 content is inconsistent and generally too low to be nutritionally significant for humans, requiring reliable fortified foods or supplements instead.

Key Points

Minimal B12 in Standard Kimchi: Despite common belief, most standard commercial and homemade kimchi contains negligible to undetectable amounts of vitamin B12.
Inconsistent B12 Content: B12 levels in kimchi are highly variable due to the specific microbial strains present and potential environmental contamination during fermentation.
Not All Bacteria Produce B12: The Lactobacillus bacteria dominant in kimchi fermentation are typically not B12 producers, making wild fermentation unreliable for B12 synthesis.
Inactive B12 Analogues: Some fermented products can contain B12 analogues that are inactive in humans and may interfere with true B12 absorption.
Fortified Foods and Supplements are Best: For reliable B12 intake on a plant-based diet, fortified foods (plant milks, cereals, nutritional yeast) and supplements are the most recommended and effective options.

The surprising scarcity of B12 in kimchi

While celebrated for its gut-health-promoting probiotics, standard kimchi is not a reliable source of vitamin B12. The common assumption that all fermented foods contain significant B12 is a misconception, especially for plant-based ferments like kimchi.

The B12 production problem

Vitamin B12 is produced exclusively by microorganisms, not by animals or plants. The bacteria responsible for fermenting kimchi, primarily various species of Lactobacillus, are not known to be B12 producers. Any trace amounts of B12 found in kimchi are typically due to environmental microbial contamination during the preparation process. This means that the presence and quantity of B12 are unpredictable and not a guaranteed feature of the final product. Even with special inoculation techniques using B12-producing bacteria, the resulting B12 content remains low.

Inconsistent levels and inactive analogues

Scientific studies have confirmed the low and inconsistent B12 content in kimchi. A 2008 study found commercial kimchi contained only 0.013–0.03 µg of B12 per 100g, while a broader 2023 review concluded that most traditional Asian fermented foods contain less than 0.5 µg per 100g. To meet the recommended daily intake of 2.4 µg for adults, one would need to consume an unfeasibly large quantity of kimchi. Adding to the issue, some studies suggest that certain fermented foods may contain inactive B12 analogues, which are structurally similar to B12 but are not biologically available to humans and can even interfere with the absorption of true B12.

A comparative look: kimchi vs. other B12 sources

To highlight why kimchi is not a dependable B12 source, it's helpful to compare its content with other food options. The following table provides a general overview, noting that B12 levels in fermented products can vary significantly.


Food Source	Type	Estimated B12 Content	Reliability for B12 Intake
Beef, 3oz	Animal Product	1.5 µg	High (Excellent source)
Clams, 3oz	Animal Product	84 µg	High (Excellent source)
Fortified Cereal, 1 serving	Fortified Vegan Food	6 µg	High (Reliable source for vegans/vegetarians)
Fortified Nutritional Yeast, 1 tbsp	Fortified Vegan Food	~5 µg	High (Reliable source for vegans/vegetarians)
Purple Laver (Nori)	Plant/Algae	Up to 77 µg/100g dry weight	Variable (Bioavailable but depends on species and processing)
Tempeh	Fermented Soy	Variable, but some strains produce it	Variable/Unreliable (Unless explicitly fortified)
Standard Kimchi	Fermented Vegetable	0-0.2 µg/100g	Very Low/Unreliable (Not a practical source)
Sauerkraut	Fermented Vegetable	Trace to low, mostly inactive analogues	Very Low/Unreliable

Safer strategies for plant-based B12

Given the unreliability of kimchi and other wild-fermented plant foods for vitamin B12, vegans and vegetarians must employ a safer, more consistent strategy to meet their daily needs. This is critical for preventing deficiency, which can cause anemia and neurological problems.

Here are the most reliable options:

Fortified Foods: Many plant-based products have B12 added during manufacturing. Common examples include fortified plant milks (e.g., soy, almond), breakfast cereals, and yeast extracts. Always check the nutrition label to ensure B12 fortification.
Nutritional Yeast: Often a go-to for vegans, nutritional yeast has a cheesy flavor and is frequently fortified with significant amounts of B12. A tablespoon can often provide more than the daily recommended intake.
Supplements: Vitamin B12 supplements are a safe and effective way to ensure adequate intake, especially for those with low absorption or strict plant-based diets. The Vegan Society and other health organizations recommend regular supplementation.

Conclusion

While kimchi is a delicious and healthy fermented food, rich in probiotics that support gut health, it is a poor source of vitamin B12. The notion that it can be a primary B12 source for plant-based diets is largely unsupported by scientific research. Any B12 detected in kimchi is typically present in negligible and inconsistent amounts and can sometimes be inactive. For reliable B12 intake, especially for vegans and vegetarians, relying on fortified foods, nutritional yeast, and/or supplements is the safest and most effective strategy. Enjoy kimchi for its flavor and probiotic benefits, but look to other sources for your B12 needs.

More information on vegan B12 sources can be found here

Frequently Asked Questions

No, you should not rely on kimchi as your primary source of vitamin B12. The amounts found in standard kimchi are negligible and inconsistent. Relying on it could lead to a deficiency.

Claims about B12 in kimchi often stem from the fact that it's a fermented food, or from studies involving specific, inoculated bacterial strains that are not used in typical production. Trace amounts from environmental contamination might also be detected, but are not reliable.

Yes, fortified foods like cereals, nutritional yeast, and plant milks are a much more reliable and consistent source of B12 for those on a plant-based diet.

Pseudo-vitamin B12 is an inactive compound that is structurally similar to B12 but not usable by the human body. It can be found in some fermented products and can interfere with the absorption of true B12.

The B12 content in homemade kimchi is also inconsistent and unreliable, as it depends on the wild bacteria present during fermentation. Commercial products are unlikely to contain significant amounts unless specifically fortified.

Excellent animal-based sources of vitamin B12 include clams, salmon, trout, beef, milk, and eggs.

Reliable plant-based sources of vitamin B12 are fortified foods like plant milks and cereals, as well as fortified nutritional yeast. Supplements are also a very dependable option.