Vitamin B12 deficiency

Vitamin B12 is a water soluble vitamin also known as cobalamin. It is essential for the production of RBC(red blood cells), DNA and functioning of nervous system.

Human body does not make vitamin B12 hence consumption of foods that contain vitamin B12 is required. Also, it is not stored for longer durations hence foods with vitamin B12 content should be consumed regularly.

Vitamin B12 is naturally found in animal origin foods, including meats, fish, poultry, eggs and dairy. However, it can also be found in products fortified with B12, such as some varieties of bread and plant-based milk.

Who are at risk?

People who do not consume enough vitamin B12 or are unable to absorb it through their food are at risk of vitamin B12 deficiency.

It includes-

  • Elderly
  • Surgical removal of part of gut that absorbs B12.
  • Diabetics on drug metformin
  • People who follow strict vegan diet
  • Taking long term antacid for heartburn
  • Heavy drinkers

Symptoms of vitamin B12 deficiency

Mild deficiency does not have any symptoms and it may take years to show any symptoms of deficiency.

When left untreated,symptoms are-

  • Weakness, tiredness, or lightheadedness
  • Palpitations and shortness of breath
  • Pale skin
  • Smooth tongue
  • Constipation, diarrhea, loss of appetite, or gas
  • Nerve problems like numbness or tingling and muscle weakness
  • Vision loss
  • Mental problems like depression, memory loss, or behavioral changes



     Diagnosis is mainly based on symptoms and physical examination by your physician.

He may order some blood tests to find-

  • whether you have a lower level of haemoglobin (a substance that transports oxygen) than normal
  • whether your red blood cells are larger than normal
  • the level of vitamin B12 in your blood
  • the level of folate in your blood

A normal level of vitamin B12 in your bloodstream is between 190 and 900 nanograms per milliliter (ng/mL).

If your test shows B12 levels of less than 150 ng/dL, your physician may want to test for methylmalonic acid. If you have vitamin B12 deficiency, methylmalonic acid levels may be higher.


Treatment of vitamin B12 deficiency depends on cause.Vitamin B12 deficiency anaemia is usually treated with injections of vitamin B12, in a form called hydroxocobalamin.These are given weekly. After the initial treatment, further treatment depends on the cause like dietary insufficiency.

People who follow strict vegan diets are encouraged to include food fortified with vitamin B12 and to include food with vitamin B12 content. They can be prescribed Vitamin B 12 tablets to be taken orally too.

If diet is not the cause of b12 deficiency, you may be advised to take hydroxocobalamin injections every 3 months.


As vitamin B12 deficiency can be easily treated, complications are rare. Few complications arise when it is not treated for long durations like vision problems, memory loss, incoordination, sensation of pins and needles, infertility and risk of nervous system defect in baby in pregnancy.

Vitamin B12 deficiency is a treatable condition and most cases of vitamin B12 deficiency can be avoided by including food sources with vitamin B12 content in your diet. Discuss with your physician if you follow a strict vegan diet or have developed any of the symptoms.

-Dr Prerna Gaur




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