Site Map

Vitamin B12

Cobalamin; Cyanocobalamin

Vitamin B12 is a water-soluble vitamin. Water-soluble vitamins dissolve in water. After the body uses these vitamins, leftover amounts leave the body through the urine.

The body can store vitamin B12 for years in the liver.

Images

Vitamin B12 benefits
Vitamin B12 source

I Would Like to Learn About:

Function

Vitamin B12, like the other B vitamins, is important for protein metabolism. It helps in the formation of red blood cells and in the maintenance of the central nervous system.

Food Sources

Vitamin B12 is naturally found in animal foods such as fish, meat, poultry, eggs, milk, and milk products. Vitamin B12 is generally not present in plant foods. Fortified breakfast cereals are a readily available source of vitamin B12. The vitamin is more available to the body from these cereals for vegetarians. Some nutritional yeast products also contain vitamin B12.

You can get the recommended amounts of vitamin B12 by eating a variety of the foods including:

To find out if vitamin B12 has been added to a food product, check the nutrition fact panel on the food label.

The body absorbs vitamin B12 from animal sources much better than plant sources. Non-animal sources of vitamin B12 have different amount of B12. They are not thought to be good sources of the vitamin.

Side Effects

Vitamin B12 deficiency occurs when the body does not get or is not able to absorb the amount of vitamin that the body needs.

Deficiency occurs in people who:

Talk to your health care provider about taking Vitamin B12 supplements.

Low levels of B12 can cause:

Recommendations

The best way to meet your body's vitamin B12 needs is to eat a wide variety of animal products.

Supplemental vitamin B12 can be found in the following:

The Recommended Dietary Allowance (RDA) for vitamins reflects how much of each vitamin most people should receive on a daily basis. The RDA for vitamins may be used as goals for each person.

How much of each vitamin you need depends on your age and gender. Other factors, such as pregnancy and illnesses, are also important. Women who are pregnant or breastfeeding need higher amounts. Ask your provider which amount is best for you.

Dietary Reference Intakes for vitamin B12:

Infants (adequate intake)

Children

Adolescents and Adults

Related Information

Metabolism
Central nervous system

References

Mason JB. Vitamins, trace minerals, and other micronutrients. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 218.

Salwen MJ. Vitamins and trace elements. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. St Louis, MO: Elsevier; 2017:chap 26.

BACK TO TOP

Review Date: 2/2/2019  

Reviewed By: Emily Wax, RD, CNSC, University of Virginia Health System, Charlottesville, VA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

ADAM Quality Logo

A.D.A.M., Inc. is accredited by URAC, for Health Content Provider (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics. This site complies with the HONcode standard for trustworthy health information: verify here.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2019 A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.