Vitamin B12 Functions and Dosage - Information and Food Sources of Vitamin B12

Vitamin B 12 is composed of a complex tetrapyrrol ring structure and a cobalt ion in the center. Vitamin B 12 is synthesized exclusively by microorganisms and is found in the liver of animals bound to protein as methycobalamin or 5'-deoxyadenosylcobalamin. The vitamin must be hydrolyzed from protein in order to be active.

Food Sources of Vitamin B 12

Vitamin B12 is present in liver, organ meat, muscle meat, shellfish, eggs, cheese, fish, and can be manufactured in the body. Although milk contains B12, processing of milk may lead to destruction of the vitamin. Vitamin B12 is mostly found in eggs, meat, poultry, shellfish, and milk and milk products.

Functions of Vitamin B 12

Vitamin B12, like the other B vitamins, is important for metabolism. It helps in the formation of red blood cells and in the maintenance of the central nervous system.

In addition, vitamin B 12 prevents nerve damage, maintains fertility, and promotes normal growth and development by maintaining the fatty sheaths that cover and protect nerve endings . Vitamin B 12 is linked to the production of acetylcholine, a neuro transmitter that assists memory and learning. Vitamin B 12 supplementation has been shown to enhance sleep patterns, allowing for more restful and refreshing sleep.


The current recommended intake for vitamin B12 is 6 micrograms per day. Barely 100 years ago, a lack of vitamin B12 was the cause of a common and deadly disease called pernicious anemia.

What are the deficiency symptoms of vitamin B 12?

Neurological complications are associated with vitamin B 12 deficiency and result from a progressive demyelination of nerve cells. May lead to pernicious anemia, poor appetite, growth failure in children, tiredness, brain damage, nervousness, neuritis, degeneration of spinal cord, depression, lack of balance. However, deficiency can result from being unable to use vitamin B12. Inability to absorb vitamin B12 from the intestinal tract can be caused by a disease known as pernicious anemia. Additionally, strict vegetarians or vegans who are not taking in proper amounts of B12 by way of supplements are also prone to a deficiency state.

Low levels of B12 can cause anemia as well as numbness or tingling in the extremities and other neurologic symptoms such as weakness and loss of balance.

Overdosage signs of vitamin B 12

When taken in conjunction with large doses of vitamin C, nosebleeds, ear bleeding, or dry mouth may occur. No toxic effects have been reported when up to 100 µg/day are consumed. Hydroxocobalamin (a form of vitamin B12) has been recognized for more than 40 years as an effective antidote to cyanide poisoning.

How to Store the Vitamin B 12?

Heat and/or moisture may alter the vitamin. Refrigeration is recommended.

Vitamin B12 Deficiency

Pernicious anemia


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