Vitamin B12 is an essential nutrient found in food sources such as animal products and fortified foods. Also known as cobalamin, vitamin B-12 is comprised of the mineral cobalt. It is water-soluble and is absorbed in the body through the digestive system. It supports metabolism processes involving the digestive, circulatory and respiratory systems. It also aids in red blood cell formation and helps to maintain the neurological processes of the central nervous system.
Deficiencies
Unlike other water-soluble vitamins, B12 is stored in the liver and not excreted, allowing the body to draw on these stores for years. Although the body is able to store vitamin B12, the Office of Dietary Supplements states that deficiencies affect 1.5 to 15 percent of the population. Individuals with conditions that affect vitamin absorption, such as gastrointestinal disorders and pernicious anemia, are most vulnerable to deficiencies. Vegetarians are also susceptible to deficiencies if they do not supplement their diet. Deficiencies can lead to fatigue, weight loss, depression, memory problems, anemia and neurological impairments including numbness or tingling in the hands and feet.
Sources of Vitamin B12
Vitamin B12 is derived from food sources, including animal products and fortified foods, and is also available as a supplement. Vitamin B12 occurs naturally in animal products including fish, meat, poultry, eggs, milk and dairy products. It is also added to grain products, such as breakfast cereal. It is not found in plant products, making it especially important for vegetarians to supplement their diets with B-12 to prevent deficiency.
Recommended Daily Intake
The recommended daily allowance of vitamin B-12 varies by age. The Institute of Medicine recommends the following amounts of daily intake:
Adults: 2.4 micrograms, or mcg
Children
9-13 years: 1.8 mcg
4-8 years: 1.2 mcg
1-3 years: 0.9 mcg
0-1 year: 0.4/0.5 mcg
Foods Rich in Vitamin B-12
Fish and shellfish contain abundant amounts of B12 per serving. Foods in this category include: clams (99 mcg), oysters (24-35 mcg), mussels (24 mcg), mackerel (12-19 mcg), herring (10-19 mcg), tuna (9-11 mcg), crab (9 mcg), trout (6-8 mcg) and salmon (4-6 mcg).
Meats, including beef, pork, lamb and sausage, are also rich in B-12. Foods in this category include: beef liver (59-83 mcg), beef kidneys (25-27 mcg), beef chuck (5-6 mcg), beef round (4-5 mcg), pork liver (19-26 mcg), pork kidneys (8 mcg), lamb liver (60-90 mcg), lamb kidneys (28-52 mcg), liver sausage (19-20 mcg), liverwurst (13 mcg) and lunch meat (4-5 mcg).
Poultry is another source of vitamin B-12. Foods in this category include: turkey liver (49-58 mcg), turkey (28-33 mcg), chicken liver (17-21 mcg) and chicken (9-13 mcg).
Eggs and dairy products contain vitamin B-12 as well. Foods in this category include: whole egg (11 mcg), egg yolk (5 mcg), nonfat milk (4 mcg), whole milk (3 mcg) and cheese (2 mcg).
Fortified foods contain vitamin B-12 in varying amounts. This includes cold cereal (2-24 mcg) and hot cereal such as oatmeal (14 mcg).
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