Vitamin B-12 Deficiency Levels

Vitamin B-12, also known as cobalamin, is an essential water soluble vitamin that is commonly found in a variety of foods. Vitamin B-12 functions to maintain healthy nerve cells and red blood cells, as it's a coenzyme that assists with the formation of blood. A deficiency develops when the body is unable to absorb vitamin B-12 from the intestinal tract. This condition typically results from pernicious anemia, which is a special form of anemia.

Development

Pernicious anemia is the primary cause of vitamin B-12 deficiency. It develops during the end stage of an autoimmune disorder that causes the depletion of various cells in the stomach. Individuals with pernicious anemia have reduced amounts of a specialized protein, termed the intrinsic factor, that is normally secreted by the stomach. The intrinsic factor's function is to bind with vitamin B-12 to allow for its absorption into the bloodstream. Pernicious anemia causes a decrease or completely halts the intrinsic factor production, thus preventing an adequate amount of vitamin B-12 from reaching the bloodstream.

Risk Factors

Older individuals are at increased risk for vitamin B-12 deficiency because they're more likely to produce an insufficient amount of the intrinsic factor. Individuals who consume little or no vitamin B-12 in their diet, such as vegans or vegetarians, are more likely to develop pernicious anemia. Additionally, pernicious anemia is more commonly seen in people with malabsorption disorders.

Deficiency Signs

Vitamin B-12 deficiency causes general symptoms of anemia, such as pale skin, decreased energy, reduced exercise tolerance, fatigue and shortness of breath. People may experience neurological symptoms due to nerve cells being destroyed, consisting of tingling and numbness of the extremities, abnormal gait, memory loss, dementia, disorientation, visual disturbances, insomnia, and impaired bladder and bowel control. Individuals may also lose the ability to perform coordinated movements and maintain body position. The central nervous system may also be affected, leading to irritability, confusion, depression, and paranoia.

Dietary Recommendations

The recommended dietary allowance, or RDA, for vitamin B-12 for adult men and women 19 years and older is 2.4 µg/day. Vitamin B-12 can be consumed via fish, shellfish, dairy products, meats and poultry. In order to receive a day's supply of vitamin B-12, you can eat one chicken breast in addition to one hard-boiled egg, 1 cup of plain low-fat yogurt, or 1 cup of raisin bran. Vegans and vegetarians need to consume foods that are fortified with B-12, or take vitamin B-12 supplements or injections to ensure that they maintain proper blood levels.