Vitamin B12

Vitamin B12 is important for normal functioning of the brain and nervous system and for formation of blood. It is involved in cell metabolism, DNA synthesis and regulation, fatty acid synthesis, and energy production.

Deficiencies: Severe deficiency may result in potentially irreversible damage to the brain, spinal cord, and optic and peripheral nerves. Dementia, poor attention span, and depression may be early symptoms. Deficiency is common among people of all ages. The elderly and people following a strict vegetarian or vegan diet are most at risk.

Food sources: Vitamin B12 is found only in animal products. Excellent sources include organ meats and bivalve mollusks such as clams and oysters. Moderate amounts are contained in egg yolks, muscle meats and poultry, fish, fermented cheeses, and dry milk. There is no human-active form of B12 in algae such as nori and spirulina; the forms are all analogues.

2000-Calorie Diet Recommendations

Shown below are the reference numbers used to compute the Daily Value percentages that appear on the Nutrition Facts labels on foods sold in the U.S. These numbers are meant to approximate the nutrients needed for the average person consuming 2000 calories per day.

Click any of the vitamin or nutrient names below to learn more about the importance of each element, and to see detailed dietary allowances for specific population groups.

***Daily Value recommendations are based on a 2000-calorie diet. Recommendations for individuals will vary depending on gender, age, weight, and other factors.