What proteins contain vitamin B12?

January 6, 2026 •

3 min read

According to the National Institutes of Health, vitamin B12 is found almost exclusively in animal-based foods naturally, which means individuals following a vegan or vegetarian diet must rely on fortified products or supplements for this essential nutrient. This vitamin, also known as cobalamin, plays a critical role in nerve function, DNA synthesis, and red blood cell formation.

Quick Summary

Vitamin B12 is naturally present in animal products, including meat, poultry, fish, eggs, and dairy, where it is bound to protein. Vegans and vegetarians can get B12 from fortified foods like nutritional yeast, cereals, and plant-based milks.

Key Points

Animal-Based Sources: Vitamin B12 is found naturally in animal proteins like meat, poultry, eggs, fish, and dairy products.
Fortified Foods for Vegans: Individuals on plant-based diets can obtain B12 from fortified products such as nutritional yeast, plant milks, and breakfast cereals.
High-Potency Sources: Beef liver, clams, and fortified nutritional yeast are among the most concentrated sources of vitamin B12.
Essential Bodily Function: B12 is crucial for red blood cell production, DNA synthesis, and maintaining a healthy nervous system.
Risk of Deficiency: Vegans, vegetarians, older adults, and those with certain digestive disorders are at higher risk of B12 deficiency.
Supplementation May Be Necessary: For many, especially those avoiding animal products, supplementation is a reliable and safe way to ensure adequate B12 intake.

Natural Animal-Based Proteins Rich in Vitamin B12

For those who include animal products in their diet, a wide array of protein sources provide naturally occurring vitamin B12. These are often considered the most bioavailable sources, though absorption can vary.

Red Meat and Poultry

Beef liver stands out as one of the most potent sources of vitamin B12, with a 3-ounce serving offering thousands of times the daily value. Other cuts of beef and lamb also contain significant amounts, providing a readily available source of this nutrient. Chicken and turkey are moderate sources of B12, contributing to daily needs and helping to support muscle growth and repair.

Seafood

Seafood provides several excellent sources of vitamin B12, often rich in other beneficial nutrients like omega-3 fatty acids.

Clams and Oysters: These shellfish are exceptionally high in B12, with just a small serving providing well over the recommended daily amount.
Salmon and Trout: These fatty fish are not only rich in heart-healthy fats but also serve as a great source of B12.
Tuna: A convenient protein source, canned tuna also delivers a solid dose of vitamin B12.

Dairy and Eggs

For vegetarians, dairy products and eggs are important contributors of B12 to the diet. A single large egg contains a decent amount of the vitamin, while milk, yogurt, and cheese all contribute to the daily intake.

Fortified Plant-Based Sources of Vitamin B12

Since vitamin B12 does not naturally occur in plants, vegetarians and vegans must be proactive about their intake through fortified foods or supplements. The B12 added to these products is easily absorbed by the body.

Nutritional Yeast: A popular ingredient in vegan cooking for its cheesy flavor, nutritional yeast is a reliable source of B12 when fortified. A single tablespoon can provide a substantial portion of the daily requirement.
Fortified Plant Milks: Many non-dairy milk alternatives, including soy, almond, and oat milk, are fortified with B12 to help meet the needs of those on plant-based diets.
Breakfast Cereals: Certain breakfast cereals are fortified with B12, offering a convenient way to start the day with this vital nutrient. Check the nutrition label to confirm fortification levels.
Meat Substitutes and Spreads: Various meat substitutes and products like yeast extract are often fortified with B12, making it easier to maintain adequate levels.

Comparison of Vitamin B12 Protein Sources

To put these sources into perspective, here is a comparison of some common protein foods and their estimated vitamin B12 content based on research from the NIH Office of Dietary Supplements.


Source	Serving Size	Approximate B12 Content (mcg)	Notes
Beef Liver	3 oz, cooked	70.7	High protein, iron, and other nutrients
Clams	3 oz, cooked	17.0	Highest concentration of B12
Salmon	3 oz, cooked	2.6	Rich in omega-3s
Tuna	3 oz, canned in water	2.5	Convenient, widely available
Fortified Nutritional Yeast	1/4 cup	8.3–24.0	Excellent vegan option, check label
Beef, Ground	3 oz, cooked	2.4	Common and versatile protein source
Milk, 2%	1 cup	1.3	Good dairy source
Egg, Large	1 whole, cooked	0.5	Also a good source of choline
Fortified Cereal	1 serving	Varies	Check packaging for percentage daily value

The Importance of Vitamin B12

Vitamin B12 is essential for numerous bodily functions. It's a key player in the synthesis of DNA, the formation of red blood cells, and the maintenance of a healthy nervous system. A deficiency can lead to megaloblastic anemia, where red blood cells become abnormally large and cannot transport oxygen efficiently, causing fatigue and weakness. Severe or prolonged deficiency can also result in irreversible neurological damage. Proper absorption relies on a protein called intrinsic factor, which is produced in the stomach.

Conclusion

Vitamin B12 is a critical nutrient, and its natural protein sources are almost exclusively from animal products. Fortunately, for those on a plant-based diet, a growing number of fortified foods and reliable supplements make it possible to meet daily intake recommendations. Whether through animal proteins like seafood and meat or fortified vegan alternatives such as nutritional yeast, ensuring an adequate B12 intake is key to maintaining overall health and preventing deficiency. Consulting a healthcare provider or a registered dietitian is recommended to determine the best approach for your specific dietary needs. For additional information on dietary sources and daily recommendations, visit the NIH Office of Dietary Supplements.

Visit the NIH Office of Dietary Supplements for more B12 information

Frequently Asked Questions

Among the most concentrated food sources of vitamin B12 are beef liver and clams, which provide exceptionally high amounts of the vitamin in a single serving.

Yes, you can obtain sufficient vitamin B12 on a plant-based diet by regularly consuming fortified foods like nutritional yeast, fortified plant milks, and cereals, and potentially through supplementation.

B12 is produced by certain bacteria, which are ingested by animals. The vitamin is then absorbed into the animal's tissues, making animal products the primary natural dietary source.

The vitamin B12 used to fortify foods and in supplements is easily absorbed by the body, often more efficiently than the B12 from some animal products.

A deficiency in vitamin B12 can lead to serious health issues, including megaloblastic anemia, fatigue, neurological problems like tingling hands and feet, memory issues, and mood changes.

Yes, dairy products such as milk, yogurt, and cheese, along with eggs, are good sources of vitamin B12, making them important for many vegetarian diets.

The recommended daily amount of vitamin B12 for adults is 2.4 micrograms (mcg), though pregnant and breastfeeding individuals need a slightly higher amount.