B12 Supplements & Anemia

Vitamin B-12 is a water-soluble vitamin, also called cobalamin, which is essential for proper red blood cell formation; it is also needed for synthesis of DNA and conduction of nerve impulses. When lacking, it is most often the result of a condition called pernicious anemia. The terms "B-12 deficiency" and "pernicious anemia" are often used interchangeably. However, pernicious anemia itself is one cause of B-12 deficiency, as the vitamin cannot be absorbed from the digestive tract effectively in those with the disease. A B-12 deficiency can be treated with supplements containing the vitamin.

Pernicious Anemia

Pernicious anemia is an autoimmune disorder resulting from a lack of intrinsic factor, a protein needed to facilitate absorption of vitamin B-12 from the stomach. Pernicious anemia leads to a deficiency in vitamin B-12 and results in decreased red blood cell formation. Your red blood cells have the important job of carrying oxygen to all the tissues in your body. If you are lacking vitamin B-12, there are not enough red blood cells to transport oxygen to cells, leaving the cells without enough energy to perform their functions.

Symptoms of B-12 Deficiency and Pernicious Anemia

Although vitamin B-12 deficiency can also occur in those on a strict vegan diet and exclusively breastfed babies, pernicious anemia is the most common cause of this deficiency. Because your cells aren't getting enough oxygen, pernicious anemia can leave you feeling listless, tired, short of breath and dizzy. The Cigna website states it also causes your skin to become very pale, and you may also have a sore tongue, bleeding gums, nausea, loss of appetite and bouts of diarrhea and constipation. Left untreated, it can cause irregular heartbeat, muscle weakness, numbness and tingling of your hands and feet, trouble walking and confusion.

B-12 Daily Requirements

Most people obtain enough vitamin B-12 in their diet, as it occurs naturally in foods such as beef liver, eggs, cheese, clams, salmon and trout. Other foods, including yogurt, breakfast cereals and milk are fortified with it. According to the Office of Dietary Supplements, adult men require 2.4 mcg daily, while adult women need 2.4 to 2.8 mcg daily, depending on whether they are pregnant or nursing, in order to remain healthy. If you do not obtain enough B-12 in your diet or cannot absorb it through digestion, your doctor may recommend taking it via dietary supplements.

B-12 Supplementation

Pernicious anemia requires you to take supplements of vitamin B-12 for the rest of your life. At the start of treatment, vitamin B-12 is given by intramuscular injection once daily, then once weekly and finally, once monthly. Once the disease is under control, your doctor may prescribe taking high doses of an oral supplement of vitamin B-12 for maintenance. Most B-12 supplements contain the vitamin in the form of cyanocobalamin, which the Office of Dietary Supplements states is easily converted by the body to the active form it needs. Vitamin B-12 supplements are also available as a sublingual lozenge placed under the tongue and as a nasal spray.