Overview
This type of anemia occurs when the body lacks enough vitamin B12 to make healthy red blood cells. B12 is also important for nerve function, so a deficiency can affect both the blood and the nervous system. It often develops slowly over months or years.
Symptoms
- Tiredness and weakness
- Pale or slightly yellow skin
- Shortness of breath
- Numbness or tingling in the hands and feet
- Trouble with balance or walking
- A sore, red or smooth tongue
- Memory or concentration problems
- Mood changes
Causes & risk factors
- A condition that stops the gut absorbing B12 (pernicious anemia)
- A diet very low in animal products without supplementation
- Stomach or bowel surgery affecting absorption
- Certain digestive conditions
- Some long-term medicines that reduce absorption
- Older age, which can reduce absorption
Treatment & self-care
A clinician confirms the diagnosis with blood tests and identifies why B12 is low, since the cause determines how it is replaced. Treatment generally involves replacing vitamin B12 and monitoring the response, with attention to any nerve symptoms. A licensed clinician should guide treatment, as some causes need lifelong replacement.
See a doctor urgently if
- You feel persistently tired, breathless, or weak
- You notice numbness, tingling, balance problems, or memory changes
- Symptoms continue despite dietary changes
- Seek prompt care if nerve symptoms are worsening, as early treatment helps prevent lasting damage