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Publication #FCS8701

Facts about Vitamin B12 1

Linda B. Bobroff2

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Why do we need vitamin B12?

Vitamin B12 works with the B vitamin folate to make DNA, our body's genetic material. B12 is needed to protect nerve cells from damage. It also helps keep blood levels of the amino acid homocysteine low. This may help to decrease heart disease risk in some people.

Everyone needs vitamin B12. Older adults and strict vegetarians (vegans) need to be sure to get enough B12 by using fortified foods or supplements.

What happens if we don't get enough vitamin B12?

Vitamin B12 deficiency causes anemia. This affects blood and nerves. With 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.

How much vitamin B12 do we need?

The following table lists recommended daily intakes of vitamin B12.

Table 1. 

Life Stage

Vitamin B12

(µg/day)

Men, ages 19+

2.4

Women, ages 19+

2.4

Pregnancy

2.6

Breastfeeding

2.8

µg = micrograms

How can we get enough vitamin B12?

Vitamin B12 is found naturally only in foods of animal origin like meats, fish, poultry, eggs, and dairy foods. Older persons often can not absorb vitamin B12 from these foods.

Fortified breads and cereals contain vitamin B12 in a form that is easily absorbed.

You can 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:

Table 2. 

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

Here are some foods and the amount of vitamin B12 they contain:

Table 3. 

Food

Vitamin B12

(µg/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

How should foods be prepared to retain vitamin B12?

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

What about supplements?

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. Also, older adults often do not absorb vitamin B12 very well. If they don't get adequate B12 from fortified foods, they need a supplement as well.

Where can I get more information?

The Family and Consumer Sciences (FCS) agent at your county Extension office may have more written information and nutrition classes for you to attend. Also, a registered dietitian (RD) can provide reliable information to you.

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

Footnotes

1.

This document is FCS8701, one of a series of the Department of Family, Youth and Community Sciences, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published: June 2001. Revised: January 2008. Please visit the EDIS Web site at http://edis.ifas.ufl.edu

2.

Linda B. Bobroff, PhD, RD, LD/N, professor, Department of Family, Youth and Community Sciences, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Millie Ferrer-Chancy, Interim Dean.