Vitamin B12

Essential for

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.

Vitamin B12Deficiency

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.


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.


Antacids, laxatives, alcohol, estrogen, sleeping pills, cholestyramine and colchicine may raise requirements.

Therapeutic uses of supplements

Supplements are used to treat pernicious anemia, immune defi- ciency, some psychiatric disorders, fatigue, allergies and sleep disorders. Some people use vitamin B12 injections as a general tonic.


Large doses of vitamin B12 should not be used by those with low potassium levels.

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Vitamin B12 Categories:

Vitamin B12
Vitamin B12 health
Vitamin B12 absorption
Vitamin B12 deficiency
Vitamin B12 sources
Vitamin B12 recommended daily
Vitamin B12 supplements
Vitamin B12 interactions



Other Vitamins:

Vitamin A
Beta carotene
Vitamin B6
Vitamin B12
Pantothenic acid
Vitamin C
Vitamin D
Vitamin E
Vitamin K