What B12 does
Vitamin B12 helps your body make red blood cells and keep the nervous system working. Because the body stores it, a deficiency can build slowly over months or years, which is why the early signs are easy to miss.
The symptoms to look for
The NHS lists tiredness, breathlessness, a pale or yellow tinge to the skin, a sore red tongue, mouth ulcers, pins and needles, muscle weakness, disturbed vision and changes in mood, memory or concentration. These overlap with many other conditions, so a test matters rather than guessing.
Who is most at risk
Deficiency is more common with age — the NHS notes it affects a higher proportion of people over 65. It is also more likely if you follow a vegan or vegetarian diet, since B12 comes mainly from meat, fish, eggs and dairy; if you have pernicious anaemia, an autoimmune condition affecting absorption; or if you take certain long-term medicines such as some for acid reflux or type 2 diabetes.
How it is diagnosed
A simple blood test measures your B12 level. It is worth testing before starting supplements, because supplementing first can mask the result. At South London Clinic, South London, we can arrange the test and discuss the result with you.
How it is treated
Treatment depends on the cause. Where it is dietary, high-dose tablets may be enough; where absorption is the problem, B12 injections are the usual route because they bypass the gut. Left untreated, deficiency can cause longer-term nerve problems, so it is worth acting on.
Common questions
