Vitamin B12 is a water-soluble vitamin. It plays a vital role in brain function and the production of DNA and red blood cells.
Chemically, vitamin B12 can exist in a number of different forms, but all of them contain the mineral cobalt.
The vitamin can be stored in the liver for a long time, so it may take a few years for a deficiency to develop.
Vitamin B12 deficiency is quite hard to detect and so can go undiagnosed for years. Symptoms can include fatigue, lethargy, shortness of breath, pale skin (possible with a pale yellow tinge), mouth ulcers, sensations of ‘pins and needles’, disturbed vision, impaired mental function and depression. Many of these symptoms are not unique to vitamin B12 deficiency, and not everyone who is diagnosed will experience these symptoms. If you are concerned that you may be deficient you should see your GP, who may wish to carry out a blood test.
A more severe form of vitamin B12 deficiency is called pernicious anaemia. This is an autoimmune disease which occurs due to issues with a specific glycoprotein called intrinsic factor (IF), which is created in the stomach and is necessary to absorb vitamin B12. Pernicious anaemia causes the immune system to attack the cells in the stomach which produce IF. Without IF, vitamin B12 cannot be absorbed and therefore deficiency can occur. Pernicious anaemia is now treated with B12 injections.