Vitamin B₁₂

There are several vitamins. Vitamin B12 is also known as cobalamin and cyanocobalamin and is one of the group of B vitamins.

Active Forms of Vitamin B12:

There are two active forms of vitamin B₁₂ :

• deoxyadenosylcobalamin, and
• methylcobalamin

Functions of Vitamin B12:

The main functions of vitamin B₁₂ are:

• Promotes growth, especially healthy growth in children - vitamin B₁₂ is needed for cell division and the production of erythrocytes (i.e. red blood cells)
• Prevents anaemia - which results from insufficient red blood cells. Pernicious anaemia is sometimes treated with injections of vitamin B₁₂. Symptoms of anaemia can include low energy ranging from mild fatigue to extreme tiredness.
• Health of nervous system - via maintenance of myelin in the nervous system
• Synthesis of nucleic acids
• Correct functioning of Folic Acid (which is also known as vitamin B9)
• Production of serotonin and dopamine - which affect emotional outlook / "mood" and sleep patterns.
  This function is why increased intake of vitamin B₁₂ may help to alleviate depression and anxiety.
• Coenzyme for two enzymes:
  1. Methylmalonyl CoA mutase, and
  2. Homocysteine methyltransferase.

Sources of Vitamin B12:

The sources of vitamin B₁₂ come from animals so there are concerns about deficiency in vegans.

• Liver is an especially good source
• Meat e.g. beef or pork
• White fish
• Eggs (one egg per day is enough for RDA)
• Milk / Dairy products
• Brewers Yeast / Yeast Extract
• Some breakfast cereals are fortified with vitamin B₁₂

Problems due to insufficient or too much Vitamin B12:

See also what is a balanced diet?.