Exhaustion, low mood and being short of breath are all symptoms of vitamin B12

Motivated by the health benefits of a plant-based diet, Carly Minsky, then in her mid-20s, saw cutting out meat and fish as a natural and desirable step.

At first, she ‘felt great’, she says, as she committed enthusiastically to her new regimen. After a year, though, it was a different story entirely.

‘I began feeling very fatigued,’ recalls Carly. ‘It wasn’t just tiredness, it was extreme fatigue.’ She also put on weight.

‘I went on like this for six years, not sure what was wrong, and by 2020 I could barely walk because I was so exhausted,’ says the journalist, 33, from London.

Finally, concerned it might be a problem with her thyroid gland (which produces hormones to regulate metabolism), in 2021 she saw her GP, who sent her for blood tests.

Motivated by the health benefits of a plant-based diet, Carly Minsky, then in her mid-20s, saw cutting out meat and fish as a natural and desirable step. At first, she ‘felt great’, she says, as she committed enthusiastically to her new regimen. After a year, though, it was a different story entirely

Within days, Carly was summoned back to the surgery and told her vitamin B12 levels had dropped so dramatically that she would need emergency vitamin injections every other day for the next six weeks, and then high-potency vitamin B12 tablets every day for life. The cause? Her diet.

Vitamin B12 is mainly found in animal and dairy products — meat, fish, eggs, milk and cheese, for instance — and is vital for numerous key body functions, including brain health and the production of red blood cells.

A deficiency can lead to health problems including anaemia (low levels of iron in the blood), tiredness, heart palpitations, shortness of breath, nerve problems and mental health issues.

Those aged over 60, who are more likely to have dietary deficiencies, and people with pernicious anaemia, an autoimmune condition that means the body is unable to absorb B12 properly, are at risk. So, too, are vegans.

Earlier this year, the National Institute for Health and Care Excellence (NICE) reported that 6 per cent of the population under the age of 60 is deficient in B12, rising to 11 per cent among vegans.

Although Carly still ate cheese and eggs, and drank milk, her intake over those years of vegetarianism wasn’t enough and her vitamin B12 levels had dropped.

‘My GP said I was at the dangerously low end of the scale and needed immediate B12 injections,’ she says. ‘It was a huge shock. I had no idea I’d become so unwell.

‘It took two months of injections before I began to feel better, and obviously I am still taking vitamin B12 tablets daily.’

Most people get enough B12 from their diets — the recommended intake is 1.5 micrograms a day (an average diet containing chicken, fish, beef and eggs will give you enough).

‘But some people — including those on restrictive diets who do not consume animal products, or who eat a bad diet high in processed foods — do not get enough vitamin B12,’ says Sue Pavord, a consultant haematologist at Oxford University Hospitals and vice president of the British Society for Haematology.

Vitamin B12 is mainly found in animal and dairy products — meat, fish, eggs, milk and cheese, for instance — and is vital for numerous key body functions, including brain health and the production of red blood cells

She says that B12 deficiency is a seriously neglected area of public health, which affects 10 per cent of those over 60.

‘The human body is not able to make B12 and therefore needs it from food,’ she explains. ‘Early symptoms of a deficiency can be vague, such as fatigue or symptoms of anaemia — palpitations, breathlessness and exhaustion.

‘But as the deficiency progresses, neurological symptoms can develop — such as tingling in the fingers and toes, or loss of balance.’

This is because B12 is vital for the maintenance and formation of protective sheaths that cover the nerves, ensuring fast and effective transmission of messages, explains Dr Moez Dungarwalla, a consultant haematologist at Milton Keynes University Hospital.

‘A fatty substance called myelin is essential for the formation of these sheaths, and vitamin B12 plays a significant role in the synthesis and maintenance of myelin,’ he explains. ‘The neurological problems caused by B12 deficiency are in part due to damage caused to the myelin sheath.’

In extreme cases, a vitamin B12 deficiency has been linked to macular degeneration (which can lead to a decline in vision), heart disease, cognitive impairment, dementia, stroke and psychosis.

However, the vague — or lack of — early symptoms can mean some people are unaware that they are suffering from a potentially serious deficiency, as former counsellor Stephen Wright discovered.

The 70-year-old, from Dorset, only learned he had a B12 deficiency at a GP check-up two years ago. Routine blood tests revealed he was severely deficient in the vitamin and would need injections every…