Vitamin B12’s impact on the body is vast – among other things, it helps keep the body’s nerve and blood cells healthy and helps make DNA, the genetic material in all cells. Indeed, its contribution becomes woefully apparent if you become deficient in it. Martyn Hopper, Founder and Chair of the Pernicious Anaemia Society (PAS), has written extensively on this subject.
Express.co.uk spoke with Martyn, author of the upcoming Five-a-Day plus one: The B12 Cookbook, to understand how the symptoms can progress.
Martyn’s decline was particularly steep because he had a very active professional and personal life to begin with.
He was a lecturer heavily involved in further education and, in his spare time, was a keen tennis player, musician and drum teacher.
As he explained, the symptoms associated with B12 deficiency are “insidious” at first and are easily dismissed.

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READ MORE: Vitamin B12 deficiency: An ‘alarming’ sign in your eyes of a deficiency – are you at risk?
Then, one day, Martyn was teaching a lecture when he was abruptly told to head to the hospital after results from a blood test revealed he has pernicious anaemia.
Pernicious anaemia is an autoimmune disease that prevents the body from making intrinsic factor (a protein made by the stomach and needed to absorb vitamin B12 in the intestine.
It is the leading cause of B12 deficiency in the UK, according to the NHS.
By the time Martyn received his diagnosis, he “didn’t know what day it was” and had to hold onto walls and walk sideways to steady his balance.
The current testing procedures are not reliable enough to determine whether you have pernicious anaemia, he said.
Indeed, the latest Guidelines published by the Cobalamin and Folic Acid by the British Committee for Standards in Haematology, call for a more holistic approach to diagnosis.
They state:
- The clinical picture is the most important factor in assessing the significance of test results assessing cobalamin status since there is no ‘gold standard’ test to define deficiency.
- Definitive cut-off points to define clinical and subclinical deficiency states are not possible, given the variety of methodologies used and technical issues, and local reference ranges should be established.
- In the presence of discordance between the test result and strong clinical features of deficiency, treatment should not be delayed to avoid neurological impairment.
The NHS says the following about the testing regime: “Tests for pernicious anaemia are not always conclusive, but can often give your GP a good idea of whether you have the condition.”