Vitamin B12 or folate deficiency anaemia
Vitamin B12 or folate deficiency anaemia occurs when the body cannot produce enough healthy red blood cells due to insufficient levels of vitamin B12, folate (vitamin B9), or both. These nutrients are essential for red blood cell production and nervous system function.
Common causes of B12 deficiency include pernicious anaemia (an autoimmune condition affecting B12 absorption), a vegan or strict vegetarian diet, and conditions affecting the gut such as coeliac disease or Crohn's disease. Folate deficiency is usually related to diet or malabsorption.
Symptoms may include extreme tiredness, a pale yellow tinge to the skin, a sore red tongue, mouth ulcers, pins and needles, and changes in the way you walk or move. B12 deficiency can also affect mood and cognitive function.
Blood tests for active vitamin B12 (holotranscobalamin), serum folate, red cell folate and mean corpuscular volume (MCV) help diagnose and distinguish between the two deficiencies.
Causes of Vitamin B12 or folate deficiency anaemia
Causes of vitamin B12 deficiency:
- Pernicious anaemia, an autoimmune condition in which the body attacks the cells in the stomach that produce intrinsic factor, a protein essential for B12 absorption. This is the most common cause in the UK
- Dietary insufficiency, particularly in vegans and strict vegetarians, as B12 is found almost exclusively in animal products
- Malabsorption from conditions affecting the stomach or small intestine, including coeliac disease, Crohn's disease and previous gastric surgery
- Medications such as metformin and long-term proton pump inhibitors, which can reduce B12 absorption
Causes of folate deficiency:
- Inadequate dietary intake of folate-rich foods such as green leafy vegetables, pulses and fortified cereals
- Malabsorption from conditions such as coeliac disease
- Excessive alcohol consumption, which interferes with folate absorption and storage
- Increased requirements during pregnancy
- Medications such as methotrexate and certain anticonvulsants
Tests that can help check this condition
Learn more on the official NHS page .
