Vitamin B12 in Older Vegetarians

What B12 does

B12 (cobalamin) is essential for making red blood cells, for healthy nerves and the protective sheath around them, for DNA production and for brain function. Without enough, red cells become large and fragile (megaloblastic anaemia), nerves are damaged and thinking may slow. Deficiency often goes along with low folate, since both are needed for blood cell production; do not treat with folic acid alone, which can mask the anaemia while nerve damage progresses, unless the doctor has excluded B12 deficiency.

Why older vegetarians are at risk

• Diet: no or little meat, fish, eggs or dairy. Plant foods such as dal, vegetables, fruit and grains contain no reliable B12. Fermented foods such as idli, dosa, kanji and tempeh do not provide useful amounts, despite common belief; some seaweeds and mushrooms contain B12-like compounds that the body cannot use well.
• Reduced absorption with age: atrophic gastritis (a thinned stomach lining) reduces stomach acid and intrinsic factor in a considerable proportion of older adults.
• Pernicious anaemia: an autoimmune condition that destroys intrinsic factor.
• Medicines: metformin (for diabetes, taken long term), acid-reducing medicines such as proton pump inhibitors and H2 blockers, some anticonvulsants and certain other drugs can lower B12. Do not stop any of them yourself; ask the doctor about monitoring or supplements; see acidity and reflux in older adults and nutrition for diabetes after 60.
• Gut conditions or surgery: coeliac disease, Crohn's disease, weight-loss or stomach surgery, bowel resection, bacterial overgrowth, parasites.
• Alcohol excess.
• Poor appetite and low overall intake; see malnutrition in older adults: signs and prevention.
• Long-term low intake with a period of stores slowly emptying, often over three to five years or more.

Signs and symptoms

Symptoms develop gradually and are easy to dismiss as ageing:

• Tiredness, weakness, breathlessness and pallor from anaemia.
• Tingling, pins and needles or numbness in the hands and feet, burning feet, loss of balance and difficulty walking in the dark, which increase fall risk; see falls risk assessment at home and neuropathy foot care.
• Sore, red, smooth tongue, mouth ulcers, cracked mouth corners.
• Memory problems, slowed thinking, confusion, irritability, low mood or depression; B12 deficiency can mimic dementia, so it should be checked in anyone with new memory problems; see mild cognitive impairment: what it is and what families can do.
• Reduced appetite, weight loss, indigestion, constipation or diarrhoea.
• Pale yellow tinge to the skin and fast heartbeat in some.
• Dizziness or fainting.

Nerve damage can become permanent if deficiency lasts, so early detection matters. See also fatigue and anaemia in older adults and iron and anaemia in older adults, since iron deficiency and B12 deficiency can occur together.

Testing

• Serum vitamin B12 level: the usual first test. Interpretation varies by laboratory, but levels below about 200 pg/mL (150 pmol/L) suggest deficiency, and borderline levels (about 200 to 300 pg/mL) may need further testing, because symptoms can occur at borderline levels in older adults.
• Methylmalonic acid and homocysteine: more sensitive markers if the B12 level is borderline.
• Complete blood count: for anaemia, large red cells (high MCV) and low platelet or white cell counts, though B12 deficiency can cause nerve problems without anaemia.
• Folate, iron studies, kidney, liver and thyroid tests, and sometimes antibodies for pernicious anaemia.
• Further investigations such as gastroscopy if the doctor suspects stomach disease.

Ask the doctor to test B12 in older vegetarians, in long-term users of metformin and acid reducers, and in anyone with anaemia, numbness, balance trouble or memory change.

How to get B12

### Food sources

• Milk, curd, buttermilk, paneer and cheese: dairy supplies B12, though in modest amounts, so a vegetarian who has two to three servings of dairy a day may meet needs, but many older people eat less.
• Eggs: a good source for ovo-vegetarians.
• Fish, chicken, meat and organ meats for non-vegetarians.
• Fortified foods: some breakfast cereals, plant milks, soya products and nutritional yeast are fortified with B12. Check labels; see how to read a supplement label.

Recommended daily intake for adults is about 2.4 micrograms (ICMR suggests about 2.2 micrograms), a very small amount, but absorption from food declines with age.

### Supplements

• Oral B12 tablets: commonly available as cyanocobalamin or methylcobalamin, in a range of doses from small maintenance amounts (a few micrograms) to high doses of 500 to 1,000 micrograms or more. Because only a small percentage is absorbed passively when intrinsic factor is lacking, higher oral doses are used for treatment and often work well, even in people with absorption problems, though the doctor decides.
• Intramuscular injections: typically used at the start of treatment for significant deficiency or nerve symptoms, or in pernicious anaemia or malabsorption, followed by maintenance injections every few months or high-dose oral therapy, per the doctor.
• Sublingual or nasal forms exist; evidence is similar to oral.
• Multivitamins often include B12, but check the dose; see multivitamins for older adults: helpful or wasteful?.
• Never exceed the label dose, and do not use unprescribed injections or products from untrusted sources. B12 is generally considered safe even in high doses because the body excretes excess, but rare allergic reactions, skin changes or interactions can occur, and very high doses should be supervised; tell the doctor about all supplements; see supplements and medicine interactions: a safety guide.

### What treatment looks like

The doctor decides the plan based on the level and symptoms. Typical stages are repletion of stores with injections or high oral doses over several weeks, then maintenance for life if the cause persists, such as pernicious anaemia, long-term metformin or a vegan diet. Blood counts and B12 levels are rechecked. Anaemia often improves within weeks; nerve symptoms may improve slowly over months and may not fully recover. Because folic acid can correct anaemia but not nerve damage, treatment must target B12.

For vegetarian and vegan households

• Plan a reliable source: daily dairy and eggs where eaten, or fortified foods, or a supplement. Vegans should not rely on diet alone; a regular supplement or fortified foods are generally advised.
• Check levels periodically, perhaps yearly, in older vegetarians, especially those on metformin or acid reducers.
• Do not rely on idli, dosa, spirulina, seaweed, tempeh or sprouted foods for B12.
• Cook gently: B12 is fairly stable, but boiling milk for long and microwaving may reduce some; the loss is modest.
• Keep the whole diet nutritious, with protein, iron and calcium; see how much protein do older adults need, iron and anaemia in older adults and calcium and vitamin D after 60.
• Respect dietary choices and religious fasting; see fasting, festivals and older adults: staying safe.

Medicines and B12

• Metformin: long-term use can reduce B12 absorption; guidelines suggest periodic B12 checks. Never stop metformin without the doctor's advice.
• Acid reducers (PPIs, H2 blockers): reduce release of B12 from food; long-term users may need monitoring.
• Some anticonvulsants, colchicine, neomycin and nitrous oxide can affect B12.
• Other medicines are reviewed by the doctor; see polypharmacy and deprescribing and medicine side effects families should watch for.

Safety and monitoring

• Report new tingling, numbness, unsteadiness, confusion, severe tiredness, breathlessness, chest pain or fainting. Seek urgent help for chest pain, severe breathlessness, fainting, sudden weakness or speech difficulty; call 112.
• Anaemia: do not treat with iron alone without testing; see iron and anaemia in older adults.
• Check blood tests as advised, and keep a record; see keeping a health record at home.
• Fall prevention: nerve damage affects balance; use night lights, rails and good footwear; see night-time toilet trips and falls.
• Foot care if feeling is reduced; see diabetic foot care at home.

When to ask a professional

Ask the doctor for a B12 test if your parent is vegetarian or vegan, takes metformin or acid reducers long term, has anaemia, tingling, memory or balance problems or a sore tongue. Ask a dietician for a vegetarian meal plan, and a pharmacist about supplement forms, doses and interactions. Seek prompt review for worsening numbness, weakness, confusion or breathlessness.