Involved in energy metabolism, like the other B vitamins, but also plays a unique role in DNA production. It’s vital for maintaining cardiovascular, brain, and nervous system health. Because vitamin B12 is manufactured exclusively by microorganisms, it’s found mostly in animal foods that concentrate bacterially produced B12 in their cells, such as fish (especially sardines, salmon, tuna, and cod), shellfish such as shrimp and scallops, organ meat, beef, eggs, and poultry. Some fermented soy products like tempeh also contain vitamin B12.