Vitamin B12 deficiency living in adults

Overview

Vitamin B12 deficiency means your body does not have enough vitamin B12. This vitamin is important for making red blood cells and keeping your nerves healthy. When you don't have enough, you may feel tired, weak, or have problems with your thinking and balance.

Yes, vitamin B12 deficiency is fairly common, especially in older adults, people who follow a vegan or vegetarian diet, and those with certain digestive conditions.

It can affect people of any age, but it is more common in adults over 60, people who have had stomach surgery, and those with conditions like Crohn's disease or coeliac disease.

Symptoms

Common symptoms

• Feeling very tired and weak
• Pale or yellow skin
• Shortness of breath
• Dizziness or light-headedness
• A ‘pins and needles’ sensation in your hands or feet
• Mouth ulcers or a sore tongue
• Blurred vision

Symptoms in children

• Slow growth and development
• Weakness and irritability
• Poor appetite
• Delays in reaching milestones like walking or talking

Symptoms in older adults

• Memory problems or confusion that can look like dementia
• Trouble with balance and walking
• Depression or mood changes
• Loss of feeling in the hands or feet

Causes

Main causes

• Not eating enough B12 – common in vegans and vegetarians
• Pernicious anaemia – an autoimmune condition that stops B12 being absorbed
• Problems with the stomach or small intestine – such as Crohn's disease, coeliac disease, or after weight-loss surgery
• Long-term use of certain medicines like acid reflux drugs (proton pump inhibitors) or metformin

Risk factors

• Being over 60
• Following a vegan or vegetarian diet without B12 supplements
• Having a digestive disorder that affects absorption
• Having had stomach or intestinal surgery
• Long-term use of acid-reducing medicines or metformin

When to see a doctor

See a doctor urgently if:

• You have severe symptoms like chest pain, severe shortness of breath, or sudden confusion.

Book a routine appointment if:

• You have gradual tiredness, mild tingling in hands or feet, or mouth ulcers that don't go away.

Diagnosis

A doctor will ask about your symptoms and diet, then arrange a blood test to check your B12 level and overall blood health.

Tests that may be done

• Full blood count – to check for anaemia
• Vitamin B12 level
• Folate level (another B vitamin)
• Intrinsic factor antibodies – to test for pernicious anaemia

What to expect at your appointment

A simple blood draw from your arm. Sometimes you may be asked to fast beforehand. Results usually come back in a few days, and your doctor will explain what they mean.

Treatment

Treatment depends on the cause and how severe the deficiency is. The goal is to bring your B12 levels back to normal and treat any underlying condition.

Self-care at home

• Eat foods rich in B12 – meat, fish, eggs, dairy, and fortified cereals or plant milks.
• If you are vegan, consider B12-fortified foods and talk to your doctor about supplements.
• Avoid long-term use of acid reflux medicines without medical advice if possible.

Medical treatments

For mild deficiency, high-dose B12 tablets may be given. For more severe deficiency or pernicious anaemia, B12 injections are usually prescribed. These are given by a nurse or doctor, often every few days at first, then every few months. Treatment for pernicious anaemia is lifelong. Your doctor will monitor your B12 levels with regular blood tests.

Living with this condition

If you need ongoing B12 injections, it becomes part of your routine – like getting a regular blood test. You will learn to recognise your symptoms and know when you might need a top-up. Most people feel normal between treatments.

Lifestyle tips

• Keep a regular schedule of B12 treatment as advised by your doctor.
• Eat a balanced diet that includes B12-rich foods or fortified options.
• Stay active – gentle exercise like walking can help with energy and mood.
• Manage stress with relaxation techniques or talking to someone you trust.

Diet and exercise

A healthy diet with enough B12 is important. For most people, a varied diet provides enough. If you are vegan or have absorption problems, you may need supplements. Exercise can help improve your energy levels and overall wellbeing, but start slowly if you feel tired.

Mental health and emotional wellbeing

Vitamin B12 deficiency can cause depression, anxiety, and trouble thinking clearly. These symptoms often improve with treatment. If you feel low or anxious, talk to your doctor – they can help and may refer you for extra support.

Prevention

For people whose deficiency is caused by diet, it can be prevented by eating enough B12-rich foods or taking a supplement. For conditions like pernicious anaemia, the deficiency cannot always be prevented, but it can be detected early and treated before it causes serious problems.

Screening programmes

Routine screening is not recommended for everyone. But if you are at higher risk – for example, you are over 60, vegan, or have a digestive condition – talk to your doctor about having your B12 level checked.

Complications

If left untreated

• Severe anaemia, causing extreme tiredness and heart problems
• Nerve damage that can lead to numbness, weakness, and loss of balance
• Memory loss and difficulty thinking clearly
• Permanent neurological problems if severe deficiency goes on for a long time

Long-term outlook

With proper treatment, most people make a full recovery and their symptoms go away. If nerve damage has already happened, it may take months to improve and some effects could be permanent, but treatment can stop it getting worse. The outlook is very good when the condition is found and treated early.

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