The term B-12 is applied to any vitamin within the cobalamin family. While this term can apply to a variety of compounds, the most active groups are cyanocobalamin and hydroxycobalamin. Cyanocobalamin is commonly listed as an ingredient in multivitamins while hydroxycobalamin is made naturally by bacteria in the human body. Both types of vitamin B-12 can be broken down and effectively used in the body.
Food Sources
Vitamin B-12 is bound to protein in foods and absorbed in the small intestine with the help of a substance known as intrinsic factor. Since vitamin B-12 is naturally attached to protein in food products, the best sources of B-12 are protein foods. Foods highest in vitamin B-12 are liver and other organ meat, clams, oysters, beef, eggs, milk, cheese, and other dairy products. Plant based foods do not contain vitamin B-12. The healthiest food choices for B-12 would be lean meats, fish, eggs and low fat dairy products.
Dietary Intake
Vitamin B-12 is bound to protein in foods and absorbed in the small intestine with the help of a substance known as intrinsic factor. Since vitamin B-12 is naturally attached to protein in food products, the best sources of B-12 are protein foods. Foods highest in vitamin B-12 are liver and other organ meat, clams, oysters, beef, eggs, milk, cheese, and other dairy products. Plant based foods do not contain vitamin B-12. The healthiest food choices for B-12 would be lean meats, fish, eggs and low fat dairy products.
Role and Deficiency
Vitamin B-12 is used for many important roles in the body such as the metabolism of amino acids and other substances and maintenance of the GI tract, bone marrow, and nervous tissue. Deficiencies of B-12 can cause impaired cell division which could lead to damage to the intestines and cause problems in the production of DNA. Insufficient vitamin B-12 also causes some types of anemia and related disorders. Severe B-12 deficiency can also result in neurological disorders.
B-12 In Your Diet
A balanced diet which includes both plant and animal based foods should supply enough vitamin B-12 for a healthy person. An adequate intake of meat, fish, eggs, and dairy will meet dietary needs and provide enough B-12 to maintain liver stores. Lacto-ovo-vegetarians must be sure to consume enough eggs and dairy since B-12 is only found naturally in animal products. Individuals following a vegan diet will most likely need to add B-12 supplements to their diet in order to avoid deficiency. The body produces less intrinsic factor with age meaning older adults may need supplements to maintain adequate amounts of B-12 absorption.
References
- "Krause's Food and Nutrition Therapy"; L. Kathleen Mahan and Sylvia Escott-Stump; 2008
- Centers for Disease Control and Prevention: Features: Vitamin B12 Deficiency; 2009
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