Vitamin B12 Deficiency In Adults

Vitamin B12 makes DNA in body cells, keeps the nerves and tissues healthy and plays a role in the development of red blood cells. The vitamin is the only water-soluble vitamin that can be stored in the body. Adults require 2.4 micrograms of vitamin B12 daily. A vitamin B12 deficiency, also called pernicious anemia, can occur due to lack of B12 in the diet or problems with absorption of the vitamin.

Intrinsic Factor

When discussing vitamin B12, it is important to also mention a protein called intrinsic factor. The stomach produces intrinsic factor, which binds to vitamin B12 in the small intestine so that the vitamin can be absorbed. Without intrinsic factor, it is impossible for the body to absorb vitamin B12. Even if an adequate amount of the vitamin is consumed, it will not reach the tissues.

Causes

One of the most common causes of vitamin B12 deficiency in adults is a lack of intrinsic factor. Some people experience a lack of intrinsic factor due to an autoimmune condition that attacks the stomach cells that produce the protein. A lack of intrinsic factor can also develop due to surgical removal of all or part of the stomach.

Another cause of vitamin B12 deficiency is some type of malabsorption in the small intestine. The National Heart, Lung and Blood Institute notes that this can be a result of excess bacteria in the small intestine, digestive diseases, certain medications or surgical removal of all or part of the small intestine.

A less common cause of vitamin B12 deficiency in adults is lack of the vitamin in the diet. The best sources of vitamin B12 are meat, poultry, fish and eggs, so strict vegetarians are at a higher risk of developing the deficiency.

Symptoms

Because vitamin B12 can be stored in the body, symptoms of a deficiency may take years to develop, according to "Nutrition and You," by Joan Salge Blake. When symptoms do develop, they may include fatigue, diarrhea, constipation, light-headedness, loss of appetite, difficulty concentrating, shortness of breath and a swollen tongue. If the deficiency is left untreated, it can lead to nerve damage, which can cause confusion, depression, loss of balance and numbness and tingling in the extremities, according to MedlinePlus.

Treatment

Treatment for a vitamin B12 deficiency depends on the cause. Vitamin B12 deficiency caused by a lack of the vitamin in the diet can usually be treated with oral supplementation of the vitamin. Those without intrinsic factor usually require lifelong injections of vitamin B12.