Anemia is a disease in which the body cannot produce enough red blood cells. There are several types of anemia; many of them are a result of various vitamin or mineral deficiencies. Pernicious anemia is the most common type and it is caused by vitamin B12 deficiency.
Basics
Vitamin B12 is essential for normal body function and overall health. One of the roles of vitamin B12 in the body is red blood cell production. Red blood cells deliver oxygen to all body organs. Abnormal red blood cells are unable to efficiently distribute sufficient oxygen where it's needed. As a result, you may feel tired and weak. Over time, the lack of oxygen may cause serious damage to the major vital organs, including the heart and brain. This is why it is important to get enough vitamin B12 in the diet. Vitamin B12 is plentiful in animal products. Meat, poultry, fish, dairy and eggs are rich sources of the vitamin.
Vegetarian Diet
There are several reasons why people can become vitamin B12 deficient. Because vitamin B12 is found mostly in animal products, vegetarians may be at an increased risk for the deficiency. If you are a vegetarian, make sure to include foods fortified with vitamin B12, such as certain breakfast cereals and soy products, or take supplements.
Intrinsic Factor
People who get plenty of vitamin B12 in the diet may also be at risk for the deficiency due to impaired absorption of the vitamin. To be able to absorb vitamin B12, your stomach must produce a special chemical called intrinsic factor. Intrinsic factor attaches to vitamin B12 in the stomach and moves it through the intestine where the vitamin absorption occurs. As people age, production of intrinsic factor in the stomach diminishes, leading to poor vitamin B12 absorption and an increase in the risk of pernicious anemia. That is why doctors encourage all elderly people to get vitamin B12 supplements, preferably in the form of injections. If you have had surgery where a part of your stomach was removed, you may also lack intrinsic factor and thus be at risk for anemia.
Intestinal Malabsorption
Some diseases of the intestine can affect absorption of vitamin B12. People suffering from malabsorptive diseases of the intestine, such as inflammatory bowel disease and Celiac disease, may develop various nutritional deficiencies, including vitamin B12 deficiency. Some medications may interfere with proper absorption of vitamin B12 in the intestine. In addition, tapeworm infection, if left untreated, can also cause a vitamin deficiency and pernicious anemia.
