Pernicious Anemia is the most common cause of vitamin B12 deficiency, it is an autoimmune condition effecting the stomach which means the immune system attacks healthy cells within the body.
Vitamin B12 deficiency is a worldwide problem and it is estimated that nearly 6 million people in the UK are deficient however it is possible that many more people have not yet been diagnosed.
Nearly 40% of members of the Pernicious Anaemia Society have had their deficiency wrongly diagnosed, meaning there is likely to be many millions of people feeling ill but who have yet to be told that they are B12 deficient