What are some examples of foods that are rich in vitamin -B-12?

Foods naturally rich in vitamin B12 include eggs, liver, shellfish, dairy products and poultry. The vitamin only occurs naturally in animal foods, but some fortified breakfast cereals also contain vitamin B12. Vegans should consider taking vitamin B12 supplements to avoid deficiency, according to the University of Maryland Medical Center.

Consuming adequate amounts of vitamin B12 is very important because permanent nerve damage can result if a deficiency becomes severe enough. A prolonged deficiency may produce symptoms including weakness, dizziness, bleeding gums, a rapid heart rate and shortness of breath. Other indicators of a deficiency include pale skin, nervousness, abdominal discomfort, numbness and diarrhea.

In addition to B12, there are seven other B vitamins, and taking too much of one B vitamin can disrupt the body's balance of the other vitamins. Therefore, people who supplement with vitamin B12 may have to take a B complex supplement containing all of the B vitamins.

Along with vegans, there are several other categories of people who are at risk of vitamin B12 deficiency. Older individuals are more likely than young people to experience deficiency, possibly because they have lower levels of stomach acid to help absorb the vitamin. People with Crohn's disease, HIV and eating disorders are also more likely to be deficient.