Vitamin B12 Deficiency: Symptoms, Causes and How to Treat It

Tingling in the feet, a tired body that no amount of rest fixes, a sore tongue and a mind that feels foggy. Many people take these as signs of weakness or age and go straight to a B12 injection from the local clinic. Vitamin B12 deficiency is common in Pakistan, and it is worth getting right, because left untreated it can cause nerve damage that does not fully recover.

What does vitamin B12 do?

Vitamin B12 helps your body make red blood cells and DNA, and keeps nerves healthy. Your body cannot make it, so it comes from food, almost entirely from animal sources. Adults need only about 2.4 micrograms a day, and the liver stores enough to last for years. That is why deficiency often develops slowly.

Vitamin B12 deficiency symptoms

• Tiredness, weakness and pale or slightly yellow skin
• Tingling, numbness or pins and needles in the hands and feet
• Difficulty walking or poor balance
• A smooth, sore or red tongue and mouth ulcers
• Shortness of breath and dizziness
• Poor memory, difficulty concentrating, low mood or irritability

Low B12 can also cause a type of anaemia in which red blood cells are large and fewer than normal. It may look similar to iron deficiency anaemia, but the treatment is different.

Who is at risk?

• Vegetarians and vegans, because B12 is found in meat, fish, eggs, milk and yoghurt and is absent from plant foods
• People over 60, whose stomachs absorb less
• Long-term users of metformin for diabetes
• People taking acid-reducing medicines such as omeprazole for years, see our guide to acid reflux and GERD
• People with pernicious anaemia, coeliac disease, Crohn’s disease or previous stomach surgery
• Pregnant and breastfeeding women who eat little animal food

How is it diagnosed?

A blood test for serum vitamin B12 is the first step. Levels below about 200 pg/mL are low, and levels in the borderline range may need extra tests such as methylmalonic acid or homocysteine. A complete blood count may show large red blood cells. Please test before you take injections or tablets, because treating blindly can hide the problem and make it harder to find the cause.

Foods rich in vitamin B12

• Liver, beef, mutton and fish
• Eggs and chicken
• Milk, yoghurt (dahi), paneer and cheese
• Fortified breakfast cereals and fortified plant milks, for vegetarians and vegans

Treatment

Treatment depends on the cause and how severe the deficiency is. Mild, diet-related deficiency is often corrected with B12 tablets in the form of methylcobalamin (mecobalamin) or cyanocobalamin, taken daily for a few months. When there are nerve symptoms, very low levels or problems absorbing B12, doctors usually start with injections and then continue with injections or high-dose tablets.

You may feel less tired within days, but nerve symptoms can take months to recover. Your doctor will repeat the blood test after a few months and then once or twice a year if the cause persists.

The folic acid warning

Taking folic acid on its own when you are actually short of B12 can improve the anaemia on paper while nerve damage quietly continues. If you are being treated for anaemia, make sure both B12 and folate levels are checked.

When to see a doctor

• Numbness, tingling or balance problems that do not go away
• Persistent tiredness with a pale or yellow look
• Memory loss or confusion, particularly in older people
• A sore tongue or mouth ulcers that keep returning

Key takeaways

• B12 comes mainly from animal foods, so vegetarians are at higher risk.
• Metformin and long-term acid-reducing medicines can lower B12.
• Test your level before starting treatment, and follow up with a repeat test.
• Nerve symptoms need early treatment, because damage can become permanent.

Related medicines on Medimart

Your doctor may recommend one of these for B12 deficiency:

• Mecobalamin (methylcobalamin): active form of vitamin B12
• Vitamin B complex: a combination of B vitamins
• Folic acid: used alongside B12 where both are low

Prescription medicines are supplied only against a valid prescription. Please take them only as advised by your doctor.

Browse vitamin and supplement products on Medimart with delivery across Pakistan. Prescription medicines are supplied only against a valid prescription.

This guide is for general information and does not replace advice from a doctor. Please get your B12 level tested before starting treatment.