Vitamin B12 - Learn About Vitamins & Minerals
B12 is a water-soluble vitamin. It can dissolve in water. It
is one of the B-complex vitamins. The B complex includes:
- pantothenic acid
- folic acid
Cobalamin is the general name for vitamin B12.
What food source is the nutrient found in?
Vitamin B12 is found in animal foods, fortified foods, and some
fermented foods. Some sources of B12 are:
- dairy products
- tempeh and miso, which both come from soy
The amount of B12 in some foods includes:
- salmon, cooked (3 oz) = 2.6 mcg (micrograms)
- beef tenderloin lean, broiled (3 oz) = 2.2 mcg
- milk (1 cup) = 0.5 mcg
How does the nutrient affect the body?
Vitamin B12 helps the body:
- make red blood cells, with folic acid, another B-vitamin
- work with many chemicals found in all body cells
- copy the genetic code within each cell
- form and maintain the nervous system
- build and maintain protective coating around nerves
- digest and use fats, carbohydrates, and some proteins for energy
- form neurotransmitters in the brain, such as serotonin, that
help regulate mood, sleep, and appetite
The recommended dietary allowance for adults, called RDA, for vitamin
B12 is 2 micrograms (mcg) per day. For pregnant women, the RDA is
2.2 mcg; for nursing women, it is 2.6 mcg. A microgram is a very
small amount. Since the only dietary sources of B12 are animal products,
strict vegetarians may need to take supplements. They may also eat
foods that have had the vitamin added.
Not getting enough vitamin B12 can cause:
- nerve damage, with symptoms such as tingling sensations and
- smooth tongue
- very sensitive skin
- muscle and nerve paralysis
Some people have trouble absorbing B12. Other people may just have
poor dietary intake. Anemia can be treated with injections of B12.
Strict vegetarians who eat no animal products, their infants, and
older people are at the highest risk for vitamin B12 deficiency.
For these people, eating fortified foods and/or taking dietary supplements
can help prevent a deficiency. High intakes of folic acid can hide
this type of anemia.
Getting too much vitamin B12 has no known symptoms or toxicity.
Since it is water-soluble, any extra leaves the body in the urine.
There is no proof that taking extra B12 boosts energy. Vitamins
do not provide calories or create energy. Vitamins can help break
down nutrients that yield energy. These nutrients include carbohydrate,
protein, and fat.
Calcium is needed to help the body absorb vitamin B12. A deficiency
of either iron or vitamin B6 can decrease the amount of B12 the
body is able to absorb.
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