What should I know before using vitamin B12?

Marjorie Nolan Cohn
Nutrition & Dietetics
Vitamin B12 (cobalamin): 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.
Before taking vitamin B12 (cobalamin), check with your doctor to make sure you need this supplement and to find out what dose would be best for you. You should also tell your doctor about any medications, prescription or nonprescription, that you take regularly, as vitamin B12 may interact with certain drugs.

Vitamin B12 is important for normal metabolism and the normal functioning of the nervous system. It's also important for the formation of red blood cells and DNA, the genetic material in all cells.

Since plant foods contain no vitamin B12, if you're vegan or vegetarian, you may need a supplement. You may also need vitamin B12 if you're pregnant or breast-feeding. Some older adults and people with digestive disorders such as celiac disease or Crohn's disease may have trouble absorbing vitamin B12 from foods and may need to take supplements.

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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.