Vitamin B12, along with folate, is essential for red blood cell production, and deficiency leads to the abnormally large red blood cells of megaloblastic anaemia.
Reduced cell haemoglobin causes tiredness, breathlessness, headaches, palpitations, poor coordination, a sore tongue and mouth ulcers. Peripheral tingling or numbness, visual disturbance, depression or declining mental abilities can also occur.
Pernicious anaemia, an autoimmune condition affecting the stomach, is the commonest reason. Normally, dietary vitamin B12 combines with a protein called intrinsic factor in the stomach, which is then absorbed in the small bowel. In pernicious anaemia, the immune system attacks the stomach cells producing the intrinsic factor, preventing vitamin B12 absorption. The exact cause is unknown – it’s commoner in older women, those with a family history or with other autoimmune conditions, such as…
