Tiredness that will not lift. Pins and needles in the feet. A memory that feels half a step slower than it used to be. It is easy to file all of that under “getting older”, and easy for a busy surgery to do the same. Sometimes the explanation is a single vitamin, one that is cheap to test for and straightforward to correct.
Vitamin B12 deficiency is one of the most under-recognised nutritional problems in adults over 50, and Ireland has the data to prove it. The Irish Longitudinal Study on Ageing (TILDA) at Trinity College Dublin, in the largest study of its kind carried out here, found one in eight adults aged 50 and over had low or deficient B12 status. Fewer than 4 per cent took any B12 or folic acid supplement.
TL;DR
- TILDA research found one in eight Irish adults aged 50+ have low or deficient vitamin B12, and one in seven are low in folate.
- The main cause after 50 is not diet but absorption: reduced stomach acid means B12 cannot be released from food.
- Long-term metformin and proton pump inhibitors (omeprazole, lansoprazole, pantoprazole) both lower B12 levels over time.
- Nerve symptoms such as numbness, tingling and unsteadiness can appear before any anaemia shows up on a blood test.
- A serum B12 test is a routine, low-cost blood test through your GP. Treatment is usually hydroxocobalamin injections or oral tablets, depending on the cause.
What B12 actually does
Vitamin B12 (cobalamin) has three jobs that matter as we age: it helps make healthy red blood cells, it maintains the myelin sheath insulating your nerves, and it is essential for DNA synthesis. Your liver holds a reserve that can last two to five years, which is why deficiency creeps up so quietly. By the time symptoms appear, it has usually been building for a long while.
Why absorption changes after 50
Most people assume a B12 problem means a diet problem. After 50, that is usually the wrong assumption.
To absorb B12 from food, your stomach needs acid to prise the vitamin away from the protein it is bound to, then intrinsic factor, made by the stomach lining, to carry it through to the small intestine. Atrophic gastritis, a gradual thinning of that lining which becomes far more common with age, reduces both. The result is food-bound cobalamin malabsorption: you eat plenty of B12 and cannot get at it.
Which is also why it gets missed. Someone eating a decent Irish diet of meat, eggs, milk and fish looks like the last person who should be short of B12, so nobody checks.
The medication link nobody mentions
Two very widely prescribed classes of medicine reduce B12 absorption, and most people taking them have never been told.
Metformin, the first-line treatment for type 2 diabetes, interferes with B12 absorption in the ileum, and the effect builds with dose and duration. If you have been taking it for years, B12 is worth checking. Your annual review under the HSE’s Chronic Disease Management Programme is the natural moment to raise it.
Proton pump inhibitors (omeprazole, lansoprazole, esomeprazole, pantoprazole) suppress stomach acid, which is precisely the acid you need to liberate B12 from food. For a few weeks, no issue. For years, and a great many people take them for years without ever being reviewed, the risk rises.
None of this means stopping your medication. It means a simple blood test should be part of the deal.
When it is autoimmune
Pernicious anaemia is an autoimmune condition in which the body attacks the cells producing intrinsic factor. It typically appears from the fifties onwards, runs in families, and keeps company with other autoimmune conditions, particularly thyroid disease and type 1 diabetes. If that sounds like you, or a close relative, say so to your GP. Antibody testing can confirm it, and it matters: pernicious anaemia is lifelong and usually needs injections rather than tablets.
Symptoms that get blamed on age
The list is frustratingly non-specific, which is half the problem:
- Persistent fatigue, breathlessness on mild exertion, pallor
- Numbness, tingling or burning in the hands and feet
- Unsteadiness on the feet, or a sense that balance has quietly deteriorated
- A sore, smooth, red tongue, or mouth ulcers
- Poor concentration, forgetfulness, irritability, low mood
Two points deserve emphasis. Neurological symptoms can develop before any anaemia appears, so a normal full blood count does not rule deficiency out. And nerve damage left untreated long enough may not fully reverse. That is the whole argument for testing early rather than waiting to see.
There is a mental health dimension too: a separate TILDA analysis found older adults with B12 deficiency had a higher risk of developing depression over four years of follow-up.
Getting tested in Ireland
Ask your GP for a serum B12 test, usually taken alongside a full blood count and folate. If you hold a medical card or GP visit card, the consultation is covered.
Serum B12 is an imperfect measure and borderline results are common. If your level sits in the grey zone but your symptoms fit, ask whether a follow-up test such as methylmalonic acid or active B12 (holotranscobalamin) would clarify things.
Folate should be checked at the same time. High folate intake can correct the anaemia of B12 deficiency while nerve damage quietly continues, which is why you should never start a high-dose folic acid supplement before B12 has been ruled out. TILDA found one in seven older Irish adults low or deficient in folate, and the rate rose steadily with age.
How it is treated
Treatment depends on the cause. Where absorption is the problem, as in pernicious anaemia or after gastric surgery, the standard approach is hydroxocobalamin by intramuscular injection: a loading course over the first fortnight, then maintenance injections every two to three months at your GP practice. Nerve symptoms usually warrant a more intensive loading schedule.
Where the cause is dietary or the deficiency mild, oral cyanocobalamin tablets may be enough. Either way it is a decision for your GP rather than the supplement aisle, not least because taking high-dose B12 before testing makes the test uninterpretable.
What you can do this week
- Check your medicine list. Long-term metformin or a proton pump inhibitor? Put B12 on the agenda at your next review, and ask whether the PPI still needs that dose.
- Eat the food anyway. Oily fish, eggs, dairy, lean red meat, liver, and fortified cereals and plant milks all supply B12. The European Food Safety Authority sets an adequate intake of 4 micrograms a day for adults.
- Mind the higher-risk groups. Vegan or largely plant-based diets, previous stomach or bowel surgery, coeliac or Crohn’s disease, or heavy drinking all make supplementation necessary rather than optional. Talk to your GP or a CORU-registered dietitian, searchable through the Irish Nutrition and Dietetic Institute.
- Do not self-diagnose from a symptom list. Fatigue and tingling have many causes. Testing is what separates them.
The bigger point
B12 deficiency matters not because it is exotic, but because it is common, cheap to detect, largely fixable, and routinely mistaken for ageing itself. At Críonna Health we keep returning to the same principle: ageing brings real changes, but not every change is ageing. When something shifts, it deserves an explanation rather than a shrug, and occasionally that explanation turns out to be a vitamin.
This article is for general information and is not a substitute for individual medical advice. If you have symptoms that concern you, speak to your GP.
📷 Photo by Evie Martinez on Unsplash
