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To B12 or not to B12?

This feature explores the importance of vitamin B12 and the vital role it plays in maintaining our overall health.

When customers ask about vitamins, what’s the first one that springs to mind? Maybe it’s vitamin C to support the immune system, vitamin D for healthy bones and teeth, or vitamin A to help protect eye health. Chances are it’s probably not vitamin B12, even though it plays an important role in keeping the nervous system healthy, making red blood cells, converting our food into energy and using folate.

Food sources of B12 include meat, fish, eggs and dairy produce such as cheese or milk. “The highest sources are found in organ meats (liver and kidney), clams, oysters and sardines,” says registered nutritional therapist Rebecca Pilkington. “Red meat and other fish sources, such as mackerel and salmon, are also good.” Some breakfast cereals or breads may also be fortified with vitamin B12.

Adults aged 19-64 need about 1.5 micrograms of vitamin B12 daily, which they should be able to get by eating a varied and balanced diet, according to the NHS. However, some people suffer from B12 deficiency, which can affect their health in a variety of ways. Potential causes of this can include:

  • Pernicious anaemia 
  • Diet
  • Stomach conditions
  • Medicines (certain medication such as proton pump inhibitors or metformin can affect B12 levels).

It’s difficult to determine the exact scale of the problem, as some patients may not even realise they have it. But according to a review in The American Journal of Clinical Nutrition, the prevalence of vitamin B12 deficiency (serum B-12 ≤ 150 pmol/L) increased substantially after the age of 69 in three UK surveys, affecting about one in 20 people aged 65-74 years and at least one in 10 of those aged 75+. Meanwhile, another study – published in the British Medical Journal (BMJ) Open – found that 12 per cent of women between the ages of 19-39 were B12 deficient, “despite seemingly adequate B12 intakes”.

Naturally, the sooner the problem can be identified, the sooner it can start to be addressed. Pharmacy teams have a clear role to play in helping to raise awareness in the community, especially among at-risk groups. The good news is that many symptoms can be treated. However, there is a greater chance of complications or permanent damage if the condition is left unchecked, so it’s important that patients seek the help they need without delay.

“Alone, each symptom doesn’t seem life-limiting, however as B12 supports cell function, it really can be”

Patient perspectives


For Kate McKeown, it was a huge relief to finally get a diagnosis after months of sensing that something wasn’t right in her early 20s. “I was exceptionally tired, beyond normal levels of fatigue. No matter how much I slept or rested, I was waking up every morning exhausted and just couldn’t get out of bed.

“There were other things too, such as brain fog – it really affected my memory and mood regulation. Those were probably secondary symptoms from being so tired.

“I’ve always been a very positive person, and there was nothing situational that happened that would have caused me to feel as low as I did. I’d never even thought about B12 deficiency – it’s something I think vegans are often told to check in on, but I didn’t realise the effect that it could have. For me, vitamins were things that I did know about, but just thought they were nice to have – it’s something I’d never put that much importance on until this happened to me.”

After struggling for three or four months, Kate says she visited her GP, but still didn’t have a diagnosis. “In the end, I actually went privately for full blood tests on everything, just to try to get some answers. That’s when it came back that I was really, really low on B12.”

She eventually had a series of seven B12 injections over 14 days, at a cost of around £30 each. “The difference was honestly life changing. It was like night and day.” Now, Kate continues with top-ups twice a year: “I see it as a self-care thing now. Rather than getting my nails done I’ll get a B12 injection!” 

Before people start racing for these as an energy-boosting pick-me-up, Rebecca urges caution: “Vitamin B12 is water soluble and thus excess amounts should be flushed out through the body. Due to this, toxicity is very rare. Having said that, a few cases have been reported and it is not advised to have the B12 injections unless a deficiency is diagnosed.

“If you have been diagnosed with a deficiency, then the injections can work really well to restore levels,” she continues. “I would suggest working with a professional to understand why levels have dropped and identify this underlying cause. For example, it could be the sign of something else going on with your digestion that is preventing absorption. If this isn’t addressed, then the injections/supplements will only work for the short term.”


Rosie McCloskey started experiencing symptoms of B12 deficiency aged 19, during her first year of university. “I was living a uni student lifestyle so my diet wasn’t great and the low B12 became apparent. A GP has since advised I’d probably been low for a long time but my diet and lifestyle had managed it when I was living at home,” she explains. “The first symptoms I noticed were heart palpitations – they are definitely the scariest symptom as I thought I was having a heart attack. For about a year I had heart palpitations on and off, I was exhausted all the time, extreme brain fog where I would start a sentence and then just give up as I’d lost my train of thought. I was initially diagnosed with anaemia but the supplements didn’t help any symptoms other than fatigue.”

In her second year of university, 18 months since her first symptoms, Rosie would repeatedly fall asleep at her desk and in meetings. The palpitations continued alongside an array of other symptoms, including dizziness, feeling lightheaded, hair loss, pins and needles/numbness in her hands and feet. “Honestly, I thought I was dying,” she says. “I was jokingly known as a bit of a hypochondriac amongst friends and family as I was in and out of the doctors for each individual symptom, but with no explanation. In August I was seen by a new GP, recently qualified, I cried to him and I felt he took me seriously – he tested for B12 along with other standard blood tests (thyroid, iron etc were all coming back fine).”

“When I got the diagnosis, I felt so much relief, my levels were extremely low and I was immediately given a course of five injections over two weeks. That was five and half years ago and I have a B12 injection every month from a private GP now. There are over-the-counter treatments like oral or sublingual tablets and mouth sprays that I’ve tried over the years, but I’ve found the injections have the best impact on me.”

Rosie suggests that anyone who thinks they may have a B12 deficiency ask their GP to add it as a standard test as part of any blood test. “Low B12 can cause low iron so being diagnosed with anaemia and taking iron tablets is just putting a plaster over the wound,” she explains. “I am a huge advocate for anyone but particularly women getting their B12 levels tested. I spent about two years suffering from something that had such an easy fix – don’t wait to find out! Also, don’t let a medical professional put the symptoms down to anxiety, some of the ones I experienced can be similar to those caused by anxiety but for me they were quite clearly low B12 driven.”

“Alone, each symptom doesn’t seem life limiting, however as B12 supports cell function, it really can be. The feeling that your whole body is shutting down on you in your early twenties is really scary, I will never stop telling women to get their B12 checked.”

Requesting a B12 test during a standard blood test is one way of ruling out deficiency.

What are the warning signs?

A lack of vitamin B12 can lead to a wide range of symptoms, and one patient’s experience may be very different to another’s.

“Pernicious anaemia can be a sign of deficiency and typically the symptoms would involve shortness of breath, heart palpitations, dizziness on standing, fatigue,” says Rebecca. “Signs linked to the nervous system include muscle weakness, numbness and tingling in the feet and hands, memory loss and – in the extreme case – dementia.

“B12 is also involved in the digestion process so a lack of this can trigger digestive symptoms including nausea, bloating and weight loss.

“Quick signs you might notice are dandruff, difficulty swallowing, inflammation of the tongue, ringing in the ears and decreased reflexes.”

The onset of symptoms can be very unsettling for those affected, especially as a quick internet search of some of the above can throw up worrying results. Pharmacy teams should direct concerned customers to their GP, who can help to rule out other conditions and arrange for them to have a blood test (also available privately). In some cases, they may be referred to a specialist, such as a dietician, haematologist (e.g. if the patient is pregnant, has neurological symptoms, or does not respond to treatment) or gastroenterologist (e.g if a bowel disorder is suspected).

“A lack of vitamin B12 can lead to a wide range of symptoms”

At-risk groups

“Given the food sources are primarily through animal products, then vegans are particularly at risk,” says registered nutritional therapist Rebecca Pilkington. “They should be taking a B12 supplement, as they will not be getting sufficient amounts through the diet.   

“Other at-risk groups include those with a digestive system complaint that may affect the absorption of vitamin B12 – this could include coeliac or Crohn’s disease. Small intestinal bacterial overgrowth (SIBO) is when you have an overgrowth of bacteria, and this utilises vitamin B12 and can lead to deficiency.

“In addition, some medications can lower B12 levels, so people should definitely speak to a professional about this if they are taking medication. Similarly, excess intake of folic acid can lead to a deficiency in B12.”   

Meanwhile, research just published in December – which looked at more than 1,700 women in the UK, Singapore and New Zealand as part of The Nipper Study – found that more than 90 per cent of participants trying to conceive had marginal or low concentrations of vitamin B12, folate, riboflavin or vitamin D.

Low levels of B12 in pregnancy have been linked with a higher risk of the baby developing a neural tube defect, such as spina bifida. Mums-to-be should check with their doctor or midwife to see whether they are getting enough B12 from their diet, or whether supplementation is recommended.

How you can help

Pharmacy teams can support patients by being “aware of the signs and advising on the underlying causes,” says Rebecca.

Vitamin B12 supplements can be picked up over-the-counter, she adds. “The most effective absorbable form is methylcobalamin. The most common form is cyanocobalamin and this is a cheaper form, but can be less effective for absorption.” With any supplements, always ask about what other medications the patient may be taking and check for any contraindications.

For Kate McKeown, getting her B12 deficiency under control has not only transformed her wellbeing but also sparked a newfound interest in nutrition. “I’ve got a bit obsessed with my health ever since this happened,” she says. “I thought, wow, if that one thing has had such a drastic effect, what else could I change? I figured out that I’m low in quite a few nutrients, which I identified as something to do with my gut, because I eat a very healthy diet. I should be getting these easily from what I eat, but the fact that I’m not suggests there’s an issue with how my body absorbs it. So now I’ve been following a gut-friendly diet to try to heal my gut for the last year or so, and that’s had a huge effect on my energy levels as well.”

There are a variety of ways to boost B12 levels, including with over-the-counter supplements available from the pharmacy.

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