Sources of Vitamin B-12

Vitamin B12, a water-soluble vitamin found in a variety of foods, helps maintain healthy red blood cells and nerve cells. It is also required to make deoxyribonucleic acid, or DNA, the genetic material found in all of the body's cells. In addition, vitamin B12 helps iron function properly in the body, aids in metabolizing fats and proteins, and helps convert food into fuel. The human body stores several years worth of vitamin B12 at a time, according to MayoClinic.com. Deficiencies are extremely rare, although strict vegans or vegetarians may have difficulty obtaining enough of the vitamin without taking a supplement.

Meat, Poultry and Fish

Vitamin B12 is found naturally in animal foods, such as meat, poultry and fish. Foods richest in the vitamin include beef liver and clams, according to the National Institutes of Health Office of Dietary Supplements. One slice of braised beef liver contains about 800 percent of the recommended daily value, and 3 oz. cooked clams contains about 570 percent. Other animal foods that provide significant vitamin B12 include rainbow trout, salmon, beef sirloin, ground beef, haddock, tuna, ham, eggs, beef kidney, beef brain, chicken, turkey, chicken liver, herring, oysters, lobster and shrimp.

Dairy Products

Dairy products are also good sources of vitamin B12, according to the University of Maryland Medical Center. A single 8 oz. serving of plain yogurt, for example, contains about 25 percent of the recommended daily value of vitamin B12. Other dairy products rich in the vitamin include milk and cheese. An 8 oz. serving of milk or a 1 oz. serving of Swiss cheese provides about 15 percent of the recommended daily value, or about 0.9mcg.

Other Sources

Vitamin B12 is generally found only in animal foods, because its synthesis is limited to bacteria. In his book "The Vitamins: Fundamental Aspects in Nutrition and Health," Gerald F. Combs explains that foods fermented with bacteria, such as nutritional yeast, may also contain small amounts of the vitamin. Fortified breakfast cereals are another good source of vitamin B12, particularly for individuals following a vegan or vegetarian diet. Cereals are typically fortified with 25 percent or 100 percent of the recommended daily value of vitamin B12, but this depends on the type of cereal and brand.