With its central role in cell growth and energy production, vitamin B12 (also known as cobalamin) is vital to the functioning of every cell in the body. The importance of this vitamin means that B12 deficiencies can have wide-ranging and serious effects.
What Causes Vitamin B12 Deficiencies?Vitamin B12 is an “essential” nutrient; this is, it must be obtained from food because it cannot be produced within the body. In the standard human diet, the major sources of vitamin B12 are animal products such as meat, milk and eggs.
Vitamin B12 deficiency can occur in the following situations.
- when there is too little B12 in the diet. This is most commonly the case in vegans, who do not eat any animal products.
- when B12 is absorbed poorly from the food in the digestive system. This has many possible causes, including lack of a substance called intrinsic factor, which aids B12 absorption; surgical removal of part of the intestine (e.g. to treat Crohn’s disease); and the side-effects of certain medications.
B12 Deficiency AnaemiaRed blood cells are produced at a rate of millions every minute and are therefore rapidly affected by vitamin B12 deficiency. Reduced numbers of red blood cells leads to anaemia, with symptoms of fatigue, shortness of breath and poor concentration.
Another type of anaemia may occur in people with B12 deficiency due to a lack of intrinsic factor; this is termed pernicious anaemia. Symptoms of pernicious anaemia affect many parts of the body and include those listed above, in addition to:
- a reddened, swollen, sore tongue (glossitis)
- pale skin
- weight loss
- gastrointestinal problems, including diarrhoea
- heart problems, including murmurs and an irregular heartbeat
- neurological problems
- frequent infections.
Psychological and Neurological Symptoms of B12 DeficiencyA vitamin B12 deficiency that has persisted over a long period of time can begin to affect the nervous system. Psychological and neurological B12 deficiency symptoms include:
- “pins and needles” sensations, tingling or numbness in the fingers and toes
- clumsiness and unsteadiness when walking
- memory problems
- depression and personality changes.