Vitamin B12 (Cobalamin) – sources, benefits and risks


vitamin b12 supplement pill

What is Vitamin B12?

Vitamin B12, sometimes referred to as cobalamin, is another of the B vitamins that helps the body convert food into energy. Also water-soluble, this vitamin must be replenished daily, either through consumption of foods high in vitamin B12 or by taking a vitamin supplement.


Cobalamin, works hand-in-hand with vitamin B9, or folate, to help produce red blood cells and to maximize the uptake of iron in the diet. Vitamin B12 and folate work together to make S-adenosylmethionine, or SAMe, a substance that boosts both immune system function and mood. SAMe is also available as a supplement, and is advertised to treat osteoarthritis pain, depression, and to serve as a liver detoxifier.


Because this vitamin is found only in animal products like meat, fish or shellfish, eggs, organ meats, milk, and other dairy products. Vitamin B12 is not found in vegetables or fruits. As a result, vegetarians (and especially vegans) may be vitamin B12-deficient. So may older people, as the body’s ability to absorb vitamin B12 becomes less over time. In fact, a randomized trial (VITACOG) has shown that this vitamin – and B complex – may slow down brain atrophy and cognitive decline among older adults.


The U.S. Department of Agriculture (USDA) regularly publishes minimum daily requirements of an entire range of vitamins and minerals. The daily recommendation for vitamin B12 is 1.2 micrograms (mcg) for children 4-8 years; 1.8 mcg for children 9-13 years; 2.4 mcg for teens; and 2.4 mcg for those over 10. Pregnant women and those breastfeeding may need as much as 2.8 mcg per day or more, given the link between blood folate, vitamin B12, and neural tube defects among newborns and infants.

Potential risks

Though this vitamin is considered safe and nontoxic, even at higher doses, individuals should always consult a health professional. Taking only one of the B vitamins, in the absence of others, can lead to a vitamin B imbalance. People with abnormal levels of red blood cells should not take vitamin B12 without medical advice. The same is true for people who have a disease of the eye called Lehrer’s Disease, because vitamin B12 supplements can cause severe damage to the optic nerve.