What is vitamin B12?

Marjorie Nolan Cohn
Nutrition & Dietetics
B12 is one of eight B vitamins, all of which help the body convert food (carbohydrates) into fuel (glucose), which produces energy. These B vitamins, often referred to as B complex vitamins, also help the body use fats and protein. B complex vitamins are needed for healthy skin, hair, eyes, and liver. They also help the nervous system function properly. All B vitamins are water-soluble, meaning that the body does not store them, and therefore considered a safe non-toxic supplement.

Vitamin B12 is an especially important vitamin for maintaining healthy nerve cells, and it helps in the production of DNA. Vitamin B12 also works closely with vitamin B9, also called folate or folic acid, to help make red blood cells and to help iron work better in the body. Folate and B12 work together to produce S-adenosylmethionine (SAMe), a compound involved in immune function and mood.

Vitamin B12, or cyanocobalamin, is a prescription medication used to increase low vitamin B12 levels. It may be given as an injection, nasal spray, or tablets. Vitamin B12 is essential for the growth and reproduction of certain cells in the body and for the function of certain enzymes in the body. It helps to make DNA, red blood cells, and keeps your nervous system working as it should. An appropriate amount of vitamin B12 can usually be obtained in a well-rounded diet that includes fish, meat, and dairy products. A low level of vitamin B12 could be caused by the following:

  • Not getting enough in the diet (vegans and vegetarians)
  • Having a gastric disease or surgery that interfers with the absorption of vitamin B12.
  • Having pathogenic bacteria or paracites grow and use the vitamin B12 in the GI tract.
  • Taking proton pump inhibitors (like Prilosec or Prevacid) or H2 blockers (like Zantac or Tagamet) for long periods of time can keep you from absorbing enough vitamin B12.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.