1. Health
Send to a Friend via Email
You can opt-out at any time. Please refer to our privacy policy for contact information.

Vitamin B-12 Requirements and Dietary Sources

Vitamin Guide


Updated July 04, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.


Vitamin B12 is found in foods of animal origin.

Greg Nicholas

Vitamin B-12, or cobalamin, is a member of the water-soluble family of B-complex vitamins. It's required for normal function of nerve cells, DNA production and your body need vitamin B-12 to make an adequate number of blood cells.

Dietary Reference Intakes

1 to 3 years: 0.9 microgram per day
4 to 8 years: 1.2 micrograms per day
9 to 13 years: 1.8 micrograms per day
14+ years: 2.4 micrograms per day

Vitamin B-12 is found naturally in meats, poultry, seafood, eggs, and dairy products -- foods that are high in protein. Supplementation should not be necessary for healthy adults, except for vegans, as vitamin B-12 is only found in animal products. Ovolactovegetarians will get vitamin B-12 from eggs or dairy products.

People with medical disorders such as pernicious anemia, celiac disease, atrophic gastritis or Crohn's disease may be at risk for vitamin B-12 deficiency.

Taking vitamin B-12 supplements will reduce homocysteine levels in your blood. Unfortunately, taking the supplements doesn't appear to reduce your risk of cardiovascular disease.

Vitamin B-12 supplements have also been recommended for improving cognitive skills, and to boost energy. But research hasn't provided sufficient evidence for these recommendations.

Also Known As: Cobalamin


"Vitamin B12." Accessed March 17, 2009. http://ods.od.nih.gov/factsheets/vitaminb12/.

Otten JJ, Hellwig JP, Meyers LD. "Dietary Reference Intakes: The Essential Guide to Nutrient Requirements." IOM, 2006.


  1. About.com
  2. Health
  3. Nutrition
  4. Start With The Basics
  5. Vitamin Glossary
  6. Vitamin B-12 Requirements and Dietary Sources

©2014 About.com. All rights reserved.

We comply with the HONcode standard
for trustworthy health
information: verify here.