Functions
Vitamin B12 is another water-soluble vitamin, part of the B complex. It contains cobalt, hence the name cobalamin. It acts as coenzymes in DNA synthesis, in protein and fat metabolism, the production of red blood cells, the activity of all cells especially these of the bone marrow and gastrointestinal tract, helps maintain the myelin sheath of nerves and detoxifies food cyanides and tobacco smoke. Cobalamin is exceptional among B vitamins in that it is recycled in the body, and a deficiency may take virtually years to develop.
Sources
Food sources include fatty fish, pork, beef, lamb, white fish, eggs, cheese, and spirulina algae. But only one percent of cobalamin in food is absorbed by simple diffusion. The presence of the protein called Intrinsic Factor in the stomach together with calcium can improve cobalamin absorption.
Uses
- Pernicious anemia (by intramuscular injection)
- Regulation of homocysteine in the blood reducing the risk of cardiovascular disease
Deficiency
A vitamin B12 deficiency leads to pernicious anemia that may be fatal if not treated in time. Persons with digestive problems, the aged and strict vegans are at risk for developing a cobalamin deficiency.
Safety
Incredibly high doses of vitamin B12 (100,000mg where 3mg is norm), produced no toxic effects. However, high doses of cobalamin can conceal a deficiency of folic acid. This record of safety notwithstanding, pregnant women should not exceed the normal dosage.