Medical Matters > Folic Acid Deficiency

ME Essential Summer 2023


A recent blood test has shown that my folic acid levels are low. My GP thinks this may be due to my rather restrictive diet. But could folic acid deficiency be caused by ME/CFS?


Folic acid deficiency can cause a specific type of anaemia where the red blood cells become enlarged. This is known as a megaloblastic anaemia. There are a number of reasons why folic acid deficiency can occur:

  • having a diet that is lacking in folic acid containing foods (e.g., greens, cereals) – which is the commonest reason.
  • gastrointestinal diseases such as coeliac disease, which reduce the absorption of this vitamin. This might be relevant in your case because coeliac disease can cause symptoms that are similar to ME/CFS. Screening for coeliac disease should form part of the clinical assessment when a diagnosis of ME/CFS is being queried.
  • pregnancy.
  • some types of medication.

If your GP cannot provide a satisfactory answer as to why your level is low, you could be referred to a hospital specialist for further assessment.

More information

Overview: Vitamin B12 or B9 (commonly called folate) deficiency anaemia occurs when a lack of vitamin B12 or folate causes the body to produce abnormally large red blood cells that cannot function properly. Red blood cells carry oxygen around the body using a substance called haemoglobin. Anaemia is the general term for having either fewer red blood cells than normal or having an abnormally low amount of haemoglobin in each red blood cell.

What causes coeliac disease? Coeliac disease is an autoimmune condition. This is where the immune system (the body's defence against infection) mistakenly attacks healthy tissue. In coeliac disease, the immune system mistakes substances found inside gluten as a threat to the body and attacks them. This damages the surface of the small bowel (intestines), disrupting the body's ability to take in nutrients from food. It's not entirely clear what causes the immune system to act this way, but a combination of genetics and the environment appear to play a part.


Information provided by The ME Association should not be construed as medical advice. Don't assume any new or worsened symptoms are simply the result of having ME/CFS or Long Covid. We recommend that any information you deem relevant is discussed with your NHS GP as soon as possible. It is important that you seek personalised medical advice from the GP who is in charge of your care and who knows you well.

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