Vitamin B12

Why We Need It

Vitamin B12 works with folate, another B vitamin, to make DNA, which is the body’s genetic material. Vitamin B12, a water-soluble vitamin, also protects nerve cells from damage and helps keep blood levels of the amino acid homocysteine low. This may help to decrease heart disease risk in some people.

Amounts Needed

Everyone needs vitamin B12. Older adults and strict vegetarians (vegans) should use fortified foods or supplements to ensure that they get enough.

Recommended Daily Intakes of Vitamin B12

Age Vitamin B12 (μg/day)
Infants birth-6 months 0.4
6 months-1 year 0.5
Children 1-3 years 0.9
4-8 years 1.2
Males 9-13 years 1.8
14 years and over 2.4
Females 9-13 years 1.8
14 years and over 2.4
pregnant 2.6
breastfeeding 2.8
μg = micrograms

Source: adapted from the Dietary Reference Intakes series, National Academies Press. Copyright 1997, 1998, 2000, 2001, 2002, 2004, by the National Academies of Sciences.


Vitamin B12 is found naturally only in foods of animal origin like meats, fish, poultry, eggs, and dairy foods. Older people often cannot absorb vitamin B12from these foods. However, fortified breads and cereals contain vitamin B12 in a form that is easily absorbed. Check the ingredient list on food labels to see if vitamin B12 has been added. Here is a sample ingredient list from a fortified cereal:

INGREDIENTS: Wheat bran with other parts of wheat, sugar, raisins, whole wheat, partially hydrogenated soybean oil, corn syrup, brown sugar syrup, nonfat milk, salt, honey, vitamin C (sodium ascorbate), vitamin B2 (riboflavin), vitamin B1 (thiamin mononitrate), folic acid, vitamin B12

Sources of Vitamin B12

Food Vitamin B12
(μg per serving)
oysters, cooked, 3 oz 30
beef, ground, extra lean, cooked, 3 oz 1.8
tuna, canned, 2 oz 1.6
fortified cereal, 1 serving 1.5
yogurt, plain, 8 oz 1.3
chicken, roasted, 3 oz 0.3
μg = micrograms
oz = ounces

Ways to Retain It

Vitamin B12 is not easily destroyed by cooking. This is good to know, since the main food sources of vitamin B 12 (e.g. meat, fish, and poultry) need to be well cooked. Other sources, like fortified cereals, may not need cooking.

If We Don’t Get Enough

Vitamin B12 deficiency causes pernicious anemia. This affects blood and nerves. With pernicious anemia, the body can’t make normal red blood cells to carry oxygen in the blood. Lack of oxygen makes people weak and tired. Nerve damage can lead to paralysis and death.


If you don’t get enough vitamin B12 from foods, you can take a multivitamin supplement. Strict vegetarians who do not eat fortified cereals or fortified soy foods need to take vitamin B12 in a supplement. In addition, older adults often do not absorb vitamin B12 very well. If they don’t get adequate B12 from fortified foods, they need a supplement, also.

For More Information

The Health Extension Agent or Nutrition Educator at your county Extension office may have more written information and nutrition classes for you to attend. Also, your doctor, health care provider, or a registered dietitian (RD) can provide reliable information.

Reliable nutrition information may be found on the Internet at the following sites:


  1. Bobroff, Linda B. University of Florida Extension. Facts About Vitamin B12. FCS8701. February 2018.
  2. National Academies of Sciences. National Academies Press. Dietary Reference Intakes series. 2004.
  3. “Office of Dietary Supplements – Vitamin B12.” NIH Office of Dietary Supplements, U.S. Department of Health and Human Services, Apr. 2021,

Originally published 07/07

If this document didn’t answer your questions, please contact HGIC at or 1-888-656-9988.

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