"Vitamin B12 is needed by all cells of the body in order to allow them to multiply. A shortage of vitamin B12 mainly affects red blood cells, because millions need be made every minute. A lack of red blood cells can lead to anaemia. The common symptoms of anaemia are tiredness, shortness of breath and palpitations.
There is also a type of B12 deficiency anaemia caused by lack of intrinsic factor. This is called pernicious anaemia. A shortage of intrinsic factor means that B12 cannot be absorbed properly. Pernicious anaemia has the same symptoms as anaemia, including tiredness, shortness of breath and fatigue. Other symptoms of anaemia can include:
* soreness of the tongue,
* loss of weight,
* pale skin, often with a lemon tint,
* intermittent diarrhoea,
* menstrual problems, and
* poor resistance to infections.
If the deficiency goes on too long, the nervous system is liable to be affected, causing:
* tingling of the fingers and toes,
* muscle weakness,
* staggering,
* tenderness in the calves, and
* confusion."