Is Kefir Good for B12 Deficiency?

December 10, 2025 •

4 min read

According to the NIH, an estimated 6% of the U.S. population has a vitamin B12 deficiency. Is kefir good for B12 deficiency? It can contribute to your B12 intake, but is generally not a sufficient standalone treatment for a diagnosed deficiency.

Quick Summary

Kefir can be a valuable dietary source of vitamin B12, but its variable content and insufficient potency mean it is not a cure for a diagnosed deficiency. It's best used as a supplement to other, more reliable B12 sources or medical treatment. The probiotic benefits may also aid overall nutrient absorption.

Key Points

Limited B12 content: The amount of vitamin B12 in kefir can be low and inconsistent, especially in non-fortified versions, making it an unreliable treatment for a deficiency.
Enhances nutrient absorption: The probiotics in kefir can improve gut health, which may help the body absorb nutrients more effectively, but this won't fix a malabsorption issue.
Not a substitute for medical treatment: A diagnosed B12 deficiency requires consultation with a healthcare professional, who may prescribe supplements or injections.
Consider fortified kefir: For a more reliable source of B12, especially for those on restricted diets, fortified kefir products can provide a more consistent dose.
Best as a dietary supplement: Use kefir as part of a balanced diet that includes other robust sources of B12, like meat, fish, eggs, and fortified cereals.

Kefir: A Source of B12, But Not a Cure

While some kefir products naturally contain vitamin B12, and the fermentation process can enrich its vitamin content, it is crucial to understand that it is generally not a robust enough solution for those with a clinical B12 deficiency. A confirmed deficiency, especially a severe one, typically requires more potent interventions, such as high-dose oral supplements or injections, under medical supervision. However, as part of a balanced diet, kefir can contribute to your overall nutrient intake.

The Fermentation Factor: Natural vs. Fortified

The vitamin B12 content in kefir can vary significantly based on its preparation. The type of milk, the starter cultures, and the fermentation process all influence the final nutritional profile. While some bacteria and yeasts in the kefir grains produce B vitamins, the resulting levels can be inconsistent. Fortified kefir, on the other hand, contains B12 that has been added artificially, ensuring a more standardized and potentially higher dose. For individuals on vegetarian diets, choosing a fortified version is often a more reliable way to ensure adequate B12 intake from kefir.

Kefir's Role in Gut Health and Absorption

A potentially more significant benefit of kefir for those with nutrient deficiencies lies in its profound effect on gut health. The diverse range of probiotics in kefir helps support a balanced gut microbiome, which is essential for proper digestion and nutrient absorption. Some causes of B12 deficiency are related to malabsorption issues caused by conditions like Crohn's disease or pernicious anemia. By improving the health and function of the digestive tract, kefir's probiotics may indirectly aid the body's ability to absorb nutrients more effectively, though it won't correct a foundational absorption disorder.

Addressing the Root Cause of B12 Deficiency

For a true vitamin B12 deficiency, it is vital to address the underlying cause rather than relying solely on dietary adjustments. Causes can range from dietary restrictions (such as veganism) to medical conditions and aging, which reduces the body's ability to absorb the vitamin. Simply adding a source of B12 to the diet might not be enough if the issue stems from poor absorption. This is why medical guidance is essential for diagnosis and treatment. In addition to supplements or injections, diet changes may be recommended, and kefir can play a supporting, rather than primary, role.

Natural vs. Fortified B12: A Comparative Look


Feature	Naturally-Occurring B12 in Kefir	B12 Fortified in Foods/Supplements
Source	Produced by bacteria during fermentation; depends on culture and milk type.	Synthetically produced; added during processing.
Potency	Levels can be inconsistent and may be too low for clinical deficiencies.	Offers a guaranteed, high dose, which is often necessary to correct deficiencies.
Bioavailability	Potentially easier to absorb than B12 from meat for some people.	Absorbed effectively, especially in its free form in supplements or fortified foods.
Ideal for	Supporting general B12 intake as part of a balanced diet; not a primary treatment.	Treating diagnosed deficiencies, especially for vegans, vegetarians, and those with absorption issues.
Considerations	May not provide enough B12 if the deficiency is significant or caused by malabsorption.	Ensures a reliable intake, bypassing potential dietary absorption issues.

Dietary Strategies to Support B12 Levels

Incorporating a variety of B12-rich foods into your diet is the most effective natural approach. For meat-eaters, this includes meat, fish, and eggs. Vegans and vegetarians can turn to fortified foods or nutritional yeast. Here is a list of other reliable food sources for B12:

Meat and Poultry: Beef, lamb, and chicken are excellent sources.
Fish and Seafood: Clams, salmon, tuna, and sardines are exceptionally rich in B12.
Dairy Products: Along with kefir, milk and cheese also contain B12.
Eggs: A good source of B12, particularly in the yolk.
Fortified Breakfast Cereals: Many cereals are fortified with B12, which can be a reliable source.
Nutritional Yeast: Often fortified and a popular choice for vegans to get their B12.

Remember, if a deficiency is caused by malabsorption, even a diet rich in B12 may not be enough, and supplements or injections may be necessary.

Conclusion: Kefir as a Supplement, Not a Standalone Cure

In summary, while kefir does contain vitamin B12 and offers significant benefits for gut health that can support overall nutrient absorption, it is not a sufficient primary treatment for a clinical B12 deficiency. Its B12 content is often inconsistent and much lower than what is required to correct a diagnosed deficiency. For most people, consuming kefir as part of a varied diet can help maintain healthy B12 levels. However, those with a confirmed deficiency should consult a healthcare provider to determine the underlying cause and receive a proper treatment plan, which may include high-dose supplements or injections. Kefir is a valuable dietary addition for general health but should not be relied upon to reverse a significant B12 deficit.

Visit the NIH Office of Dietary Supplements for more facts on Vitamin B12.

Frequently Asked Questions

No, drinking kefir is generally not enough to reverse a severe B12 deficiency. A clinical deficiency requires more concentrated and reliable forms of B12, such as supplements or injections, under a doctor's supervision.

The B12 content in kefir can vary, but typically a cup of milk kefir provides a moderate percentage of the daily value, far less than what is needed for therapeutic treatment of a deficiency.

Yes, fortified kefir is a more reliable dietary source of B12 because the vitamin has been added, resulting in a more consistent and higher dose compared to unfortified versions.

Yes, proper gut health is crucial for B12 absorption. The probiotics in kefir may support a healthy gut microbiome, which can aid in the digestive processes necessary for absorbing nutrients like B12.

The best food sources for B12 include organ meats (like liver), clams, fortified nutritional yeast, beef, salmon, and fortified cereals.

Individuals on vegan or strict vegetarian diets, older adults, and people with digestive disorders like pernicious anemia, Crohn's disease, or those who have had gastric surgery are most at risk for B12 deficiency.

The time it takes for B12 levels to increase depends on the treatment method. While supplements or injections work faster, relying solely on dietary changes with foods like kefir will likely take much longer and may not be sufficient for a diagnosed deficiency.