What Does Lack of Vitamin B12 Cause?

What Does Lack of Vitamin B12 Cause?

Vitamin B12 is a vital nutrient which is useful in overall health of an individual. It promotes production of healthy cells and neurons. In addition, it contributes to the elaboration of DNA, the genetic material present in all cells. Vitamin B12 also stops development of megaloblastic anemia, which is a variant of anemia with symptoms of weakness and persistent fatigue in affected individuals.

The body absorbs vitamin B12 from food that is ingested by two ways. In the first way, hydrochloric acid present in the stomach segregates protein from vitamin B12 from the food. The vitamin is then bonded with intrinsic factor which is a protein found in stomach which facilitates absorption of this vitamin. Some people have a type of anemia (pernicious anemia) in which they cannot produce intrinsic factor. As a result, they have difficulty absorbing vitamin B12 from all foods and dietary supplements.

Anemia Due To Deficiency of Vitamin B12 And Folate:

The blood contains three types of cells. The white blood cells that defend the organism against infections, the red blood cells that carry oxygen through the organism in an element called hemoglobin, and the platelets that contribute to the blood coagulation.

Every day millions of red blood cells are formed to replace the old ones that decompose. Nutrients in foods, such as iron, and vitamins, such as B12 and folate (also called folic acid), contribute to the formation of cells constantly.

Anemia is a disease that appears when the amount of red blood cells or the concentration of hemoglobin is reduced.

There are several types of anemia and the cause of each one is different. The most common type is iron-deficiency anemia; there is another type due to vitamin B12 or folate deficiency.

The Symptoms

Each type of anemia has its own symptoms, which depend on the cause underlying it.

However, there are some general symptoms that are related to all types of anemia. These symptoms are: tiredness, shortness of breath (dyspnea), fainting and palpitations (irregular heartbeats). There may also be headache, ringing in the ears (tinnitus) and loss of appetite.

If the cause of the anemia is the deficiency of vitamin B12, it can also appear other symptoms; one of them is the yellowing of the skin (caused by jaundice, a disease that develops when blood builds up in chemical called bilirubin). Other symptoms are: pain and redness of the tongue (glossitis), ulcers in the mouth, and alteration or decreased sense of touch.

More presenting features of vitamin B12 deficiency include reduced ability to feel pain, ambulatory disturbance, visual disturbances, irritability and depression.

Pernicious Anemia

The primary cause of vitamin B12 deficiency is believed to be pernicious anemia. This condition hampers the absorption of vitamin B12 in the body.

Other causes of vitamin B12 deficiency are rare. Nevertheless, the cause of a deficiency may be due to factors such as a lack of vitamin B12 in the diet, a stomach or intestinal disorder that prevents the absorption of vitamin B12 or some medication types.

How is it Diagnosed?

If the doctor suspects that you have an anemia, physician will usually send you for a blood test.

Hemoglobin will be analyzed from the blood and if there is less than normal, the diagnosis will be that you have anemia. Blood can also be analyzed to check the levels of vitamin B12 and folate. If the analysis shows that have a deficiency of these vitamins, this will be useful to your doctor to determine what type of anemia it is.

Once the doctor has determined that you have an anemia vitamin B12 or folate deficiency, more tests may be required to establish the underlying cause of the deficiency.


There may be neurological problems like numbness and tingling in upper and lower extremities, problems with balance, confusion, depression, memory problems, and inflammation of tongue or areas of the mouth.

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Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:February 18, 2019

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