Why is vitamin B12 necessary for good health?

Vitamin B12 (cobalamin) is essential for the proper functioning of the nervous system, normal metabolism, the formation of red blood cells and the synthesis of the genetic materials RNA and DNA.

Most people can get enough vitamin B12 from their diets by eating food that comes from animal sources, such as red meat, poultry, fish, eggs and dairy products, as well as fortified breakfast cereals. However, if you follow a vegan diet, or if you have a medical condition that makes it difficult to absorb vitamin B12 from food (such as Crohn's disease, celiac disease or pernicious anemia), you may be at risk for vitamin B12 deficiency. Talk to your doctor for more information about vitamin B12 and its role in good health.
Dr. David L. Katz, MD, MPH
Preventive Medicine
Like all vitamins, B12 is an organic compound, made from carbons (as opposed to minerals, which are inorganic), and essential for our normal metabolic function and health. Also, like most vitamins, B12 plays a wide variety of roles in our metabolism. The short list of important effects B12 has on your health includes these:
  • Vitamin B12 is essential for the manufacture of red blood cells; a deficiency leads to a characteristic kind of anemia.
  • Vitamin B12 is needed to support the normal function of nerve cells and to manufacture myelin, the insulating material that surrounds some of our nerve cells and speeds neural transmission.
  • Vitamin B12 is required for the replication of DNA.
Each of these effects is obviously quite important, but note the third one in particular. When B12 is deficient, our DNA cannot replicate normally -- meaning we can’t generate new, healthy cells. As a result, vitamin B12 deficiency can mimic all of the effects of aging.

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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.