Does Dairy Increase B12? The Surprising Truth About Its Bioavailability

October 31, 2025 •

3 min read

Vitamin B12 is an essential nutrient found naturally only in animal products like meat, fish, and dairy. While this is a known fact, many people still wonder: does dairy increase B12 levels effectively, and can it be relied upon as a primary source?

Quick Summary

Dairy products such as milk, cheese, and yogurt are natural and effective sources of vitamin B12. The B12 from dairy is highly bioavailable, meaning the body absorbs it more efficiently than from some other animal sources. Incorporating dairy into your diet can help boost your B12 intake, though total requirements and absorption can vary by individual.

Key Points

Natural Source: Vitamin B12 is produced by bacteria in ruminant animals and is naturally present in their milk and dairy products.
Superior Bioavailability: Studies suggest that the vitamin B12 from dairy products is absorbed by the body more effectively than B12 from meat or supplements.
Concentrated in Cheese: Certain cheeses, like Swiss, contain higher concentrations of B12 due to the bacteria involved in their manufacturing process.
Crucial for Vegetarians: Dairy is a key source of B12 for lacto-vegetarians, but vegans must rely on fortified products or supplements.
Absorption Varies with Age: Older adults and individuals with specific medical conditions may have impaired absorption and might require fortified foods or supplements to meet their needs.
Part of a Broader Strategy: Relying solely on dairy may not be enough for all, so a comprehensive dietary strategy including other animal products, fortified foods, or supplements is often necessary.

The Origins of B12 in Dairy

Unlike most other B vitamins, vitamin B12 is produced exclusively by microorganisms like bacteria. Plants do not naturally contain it, which is why those on strict vegan diets must turn to fortified foods and supplements. For dairy, the B12 content is a result of synthesis within the digestive system of ruminant animals, such as cows. These microorganisms produce the vitamin, which is then absorbed by the animal and stored in its tissues and milk. When we consume dairy products, we are therefore benefiting from this natural biological process.

Dairy Products and B12 Bioavailability

One of the most significant advantages of obtaining vitamin B12 from dairy is its high bioavailability. Bioavailability refers to the proportion of a nutrient that is absorbed and utilized by the body. Several studies have shown that the B12 present in milk and other dairy products is more readily absorbed than the B12 from sources like meat, fish, and eggs. Research using a pig model, which is comparable to human nutrition, found that Cheddar cheese had a high bioavailability, outperforming both synthetic B12 supplements and other dairy products tested. The specific composition of dairy, including its proteins, is believed to facilitate this enhanced absorption. This makes dairy a particularly effective way for many people to get their vitamin B12, especially lacto-vegetarians.

B12 Content in Common Dairy Products

Milk: A single cup of 2% milk can provide about 1.3 micrograms (mcg) of vitamin B12, accounting for over 50% of the recommended daily value for adults. Its liquid form and protein profile contribute to its strong absorption.
Yogurt: Plain, fat-free yogurt is another excellent source. An 8-ounce serving can contain around 1.0 to 1.2 mcg of B12. The fermentation process affects the final vitamin content, but it remains a strong contributor.
Cheese: B12 concentration varies widely across different cheeses. Swiss cheese is particularly high due to the activity of specific bacteria (Propionibacterium shermanii) during its ripening process. Swiss cheese and mozzarella can contain significantly more B12 per gram than cheddar or cream cheese.

Dairy vs. Other B12 Sources

To understand the full picture, it's helpful to compare dairy with other sources of vitamin B12. While dairy is a significant source, it is not the most concentrated, and other factors affect overall intake.


Source	Example Serving	B12 Content (approx.)	Bioavailability Notes
Dairy	1 cup milk	~1.3 mcg	High; absorbed more efficiently than B12 from meat.
Meat	3 oz. ground beef	~2.4 mcg	Good, but bioavailability may be lower than dairy.
Fish	3 oz. salmon	~2.6 mcg	Excellent; one of the richest natural sources.
Eggs	1 large egg	~0.5 mcg	Moderate; lower absorption rate than milk.
Fortified Cereal	1 serving (check label)	Varies greatly	High; fortified foods are a reliable source for non-dairy consumers.
Nutritional Yeast	1 tbsp (fortified)	~2.4 mcg	Excellent; a common vegan source.
Clams	3 oz. cooked	~17 mcg	Extremely high; one of the highest concentrated natural sources.

Limitations and Considerations for Dairy B12

While dairy is a potent source, it's not a universal solution for everyone. Several factors can influence B12 status, and for some, relying solely on dairy is not enough.

Dietary Restrictions: For vegans, who do not consume any animal products, dairy is off-limits. Fortified plant-based milks and nutritional yeast become necessary alternatives, along with supplements.
Aging and Absorption: Older adults, especially those over 75, often have reduced stomach acid (hydrochloric acid), which is required to release B12 from food proteins for absorption. For this group, B12 from fortified foods or supplements is often more readily absorbed than naturally occurring food B12.
Medical Conditions: Certain medical conditions, such as pernicious anemia, atrophic gastritis, Crohn's disease, and some bariatric surgeries, can severely impair B12 absorption. In such cases, high-dose oral supplements or B12 injections are required, regardless of dairy intake.

Conclusion: The Final Word on Dairy and B12

In conclusion, dairy products are a significant and effective source of vitamin B12 for many people. The bioavailability of B12 from milk, cheese, and yogurt is notably high, making them a valuable part of a balanced diet for those who consume them. However, the importance of dairy as a B12 source varies depending on individual dietary choices and physiological factors. While dairy can help prevent deficiency, individuals with absorption issues or those following a vegan diet must consider alternatives like fortified foods and supplements to maintain adequate levels. For personalized advice, it is always best to consult a healthcare provider or a registered dietitian. For more information on dietary needs, the NIH Office of Dietary Supplements provides authoritative resources on vitamin B12.

Frequently Asked Questions

For omnivores, dairy contributes significantly to B12 intake. For lacto-vegetarians, it is a primary source. However, depending on individual needs and health factors like age and medical conditions, relying solely on dairy might not be sufficient, and supplementation may be needed.

Both milk and yogurt are good sources of vitamin B12. Research has shown high bioavailability for B12 from milk and dairy in general, making both excellent options. The final content can vary based on processing and fermentation.

Yes, most cheeses contain vitamin B12. However, the concentration can differ significantly. Swiss cheese, for example, is known for its particularly high B12 content due to the specific bacteria used in its production.

Studies suggest that the specific proteins in milk and the way B12 is bound within the dairy matrix may facilitate its release and absorption in the digestive tract more efficiently than in meat.

Yes, fortified plant-based milks are excellent sources of B12, especially for vegans. Since they have B12 added, they can provide a reliable and consistent amount of the vitamin.

While some processing can affect vitamin levels, B12 is relatively heat-stable, and significant amounts are retained during pasteurization and common cooking methods. However, prolonged high-heat cooking may lead to some vitamin loss.

For individuals who cannot consume dairy due to lactose intolerance or allergy, excellent B12 sources include fortified breakfast cereals, nutritional yeast, certain fortified plant-based milks, and of course, dietary supplements.