Low B12 and memory loss in older relatives: ask the GP

It usually starts small. A name that won't come. The same question asked twice in one visit. A pan left on the hob.

And because Mum is 78, or Grandad is 84, everyone quietly files it under 'getting older'.

Sometimes that's right. Sometimes it isn't. It could be old age, or it could be low B12, and that's one of the simplest things to rule out.

A phone call a pharmacist never forgot

When I filmed with Dennis Gore, who has spent 60 years as a pharmacist, he told me about a call he still talks about. Years ago he spoke about vitamin B12 on a radio programme in Liverpool. Some time later, a listener phoned his shop to tell him what had happened with her mother.

I won't retell the details here; the lesson is the part that matters. Low B12 can cause memory problems and confusion that are easy to put down to age, and a simple blood test at the GP can rule it in or out.

Why B12 is worth a question

Your body uses vitamin B12 to make healthy red blood cells and to keep the nervous system working. When levels run low, the NHS lists problems with memory, understanding and judgement among the possible signs, alongside extreme tiredness, pins and needles, and a sore, red tongue. Confusion can be part of the picture too, and the NHS notes that some of these problems can appear even before anaemia shows up on a blood test.

It's also more common as we get older. The NHS puts vitamin B12 or folate deficiency at around 1 in 10 people aged 75 or over, and around 1 in 20 people aged 65 to 74.

Who's more likely to run low

• Older adults. The body can absorb B12 less well with age.
• People on certain medicines. The NHS names some indigestion medicines called proton pump inhibitors, and some anticonvulsants, as affecting how much of these vitamins the body absorbs. That's never a reason to stop a medicine. It's a reason to mention B12 at the next medication review.
• People with a long-term restricted diet, including a vegan diet without fortified foods or a B12 supplement.

What to do next

1. Book a GP appointment and say it plainly: 'Their memory has changed. Could we check B12 and folate?' A blood test, alongside the symptoms, is how it's usually diagnosed.
2. Take a list of every medicine, vitamin and supplement they take, including anything bought over the counter. Your pharmacist can look it over with you too.
3. Don't guess at doses. If levels are low, the GP will advise on treatment, and the NHS notes that B12 is usually started with injections. Agree any supplement and its dose with a doctor or pharmacist, and don't go over the label dose without advice.
4. Treat sudden confusion differently. Confusion that comes on over hours or a day or two needs medical help the same day, not a routine appointment.

Questions worth asking at the appointment

It can help to go in with a few written questions, especially if you're attending on someone's behalf:

• Could a low B12 or folate level be part of this, and can we test for both?
• Could any of their regular medicines be affecting how they absorb B12?
• If the result is low, what happens next, and who will follow it up?
• If the result is normal, what else should we look at?
• When should we come back if nothing changes, or if things get worse?

Write down the answers, or ask if you can record them on your phone. Appointments go quickly, and it's easy to forget the detail on the way home.

How to support them at home

While you wait for results, keep a simple diary of what you notice: dates, what happened and how they seemed that day. Patterns are easier to spot on paper than in memory, and the GP will find it useful. Keep meals regular and varied, and make sure they're drinking enough, because tiredness and dehydration can make confusion look worse.

Remove harm before adding benefit

This is the founding principle at its simplest. Before assuming the worst, or adding something new, check the basics. A missing vitamin is one of the few causes of memory change that's straightforward to test for.

Quick answers

Can low B12 cause memory loss? The NHS lists problems with memory, understanding and judgement among the possible signs of low B12, so it's worth asking the GP to check.

How is low B12 found? Usually through a blood test, alongside the symptoms. Ask about folate at the same time.

Should we just buy a B12 supplement? Get the blood test first, then agree any supplement and dose with a doctor or pharmacist.

Everyone is different

Memory changes have many possible causes, and B12 is only one of them. Some people will have normal results and need a different conversation. That's still a good outcome: you've ruled something out and moved closer to the answer.

Dennis Gore is a natural health legend: at his Prestwich pharmacy since 1966, and formerly on BBC Radio Manchester, Granada TV and online shows. Dennis's consultations are his own, separate from Just Ask Omar.

Sources: NHS: Vitamin B12 or folate deficiency anaemia (accessed 1 November 2026).