Quick guide to Vitamin B12 (Cobalamin)
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- energy release from food
- amino acid and fatty acid metabolism
- healthy nerves, blood cells, skin and hair
- production of genetic material
- growth and development
Absorption and metabolism
Vitamin B12 requires a compound known as intrinsic factor for absorption.
Deficiency
Deficiency leads to pernicious anemia with symptoms of fatigue, lightheadedness, headache and irritability. Other symptoms include nausea, loss of appetite, sore mouth, diarrhea, abnormal gait, loss of sensation in hands and feet, confusion, memory loss and depression.
Sources
These include meats, fish, eggs and dairy products.
Daily recommended dietary intakes
- Men - 2.4 mcg
- Women - 2.4 mcg
- Pregnancy - 2.6 mcg
- Lactation - 2.8 mcg
Toxic effects of excess intake
There have been no reports of toxic effects.
Therapeutic uses of supplements
Supplements are used to treat pernicious anemia, immune deficiency, some psychiatric disorders, fatigue, allergies and sleep disorders. Some people use vitamin B12 injections as a general tonic.
Interactions
Antacids, laxatives, alcohol, estrogen, sleeping pills, cholestyramine and colchicine may raise requirements.
Cautions
Large doses of vitamin B12 should not be used by those with low potassium levels.