15/12/2025
Dr Mark Porter said millions may be suffering from vitamin B12 deficiency but have no idea - and it can have a big impact on daily lives
TV doctor has explained how a potentially serious condition goes undiagnosed a lot of the time. Dr Mark Porter who has appeared both on the BBC and ITVâs Good Morning Britain said that if you are not absorbing this crucial vitamin properly then it can lead to a host of symptoms including lack of energy, memory issues, pins and needles and even paralysis.
Writing in his health column in the Times Dr Porter said the deficiency is very common but people donât realise theyâve got it. He explained: âB12 deficiency is both common and underdiagnosed.
âB12 is essential for the production of red blood cells and normal functioning of the brain and nervous system. Deficiency can cause numerous symptoms ranging from lack of energy, memory issues, a sore tongue, weakness and pins and needles, to anaemia, breathlessness, confusion and, rarely, even paralysis and death.
âIt is easily missed because it tends to develop slowly over a few years, and the signs may not show up in routine blood tests which donât check levels of the vitamin unless specifically requested.â
The vitamin occurs naturally in animal products such as meat, fish, milk and eggs but isnât easily absorbed. Dr Porter explained: âYou need a good balanced diet, a healthy bowel, plenty of stomach acid and the presence of a special protein called intrinsic factor (IF) to have a good chance of maintaining optimum levels. And millions of people in the UK struggle with one or more of these, putting them at risk.â
Itâs more common in older people but the young are at risk too - in factt 1 in 30 young adults may be affected, rising to 1 in 25 in middle age, and as many as 1 in 5 in people over 80. He added that certain groups are at particular risk including at least one in ten vegans is thought to be deficient and it is vital that all vegans take supplements and/or regularly consume B12 fortified foods such as some plant-based milks, soy products and cereals.
He said that people should ask questions themselves because if they have a blood test itâs often not spotted unless it is specifically tested for. Dr Porter said: âThe key to diagnosing B12 deficiency is to have a high index of suspicion. The NHS does not, and cannot, routinely screen the population using regular blood tests, so diagnosis depends on spotting the symptoms and/or adding in the test when monitoring others at higher risk because of underlying health conditions.
âFor most people a standard NHS B12 blood test will clinch the diagnosis, with pathways advocating either B12 injections or high-dose (1,000mcg) tablets, depending on the individualâs circumstances, symptoms and blood results.
âOne word of caution. A course of high-dose supplements given for at least three months will resolve many deficiencies but, unless diets/medication/underlying conditions change the problem is likely to recur. Many people will require lifelong supplements or, at the very least, future testing to check they are maintaining good levels.â
B12 deficiency symptoms/signs include:
Abnormal findings on a blood count, such as anaemia
Cognitive difficulties, including memory problems and other symptoms of dementia
A sore/inflamed tongue
Unexplained eyesight changes, including blurred vision
Mental health problems, such as anxiety and depression
Neurological symptoms, including impaired balance, weakness, pins and needles or numbness
Unexplained fatigue.
