Beef liver is one of the most concentrated sources of vitamin B12. A 4-ounce raw serving contains 67 micrograms (mcg) of B12, nearly 3,000% of the recommended dietary allowance (RDA) for adults.

The amount of vitamin B12 in an egg depends on its size and a large egg contains about 0.6 mcg of vitamin B12 in it. The recommended daily intake for most adults is 2.4 mcg, meaning one large egg ...

In the case of vitamin ... B12 “varies depending on age, sex and other individual conditions,” says Aguirre. For “most adults ...