What causes vitamin B12 deficiency?
Although vitamin B12 deficiency may result from a number of factors, the major reason is lack of adequate B12 absorption. In order to be absorbed in the small intestine, vitamin B12 in food must be combined with an intrinsic factor-a protein made by the stomach. Receptors for B12 absorption occur in the ileum, the lowest portion of the small intestine. Adults secrete about 5-7 micrograms of B12 in the bile daily. Normally we reabsorb most of this. As long as vitamin B12 absorption is effective, a deficiency may not readily develop. However, it can take only about three years to become B12 deficient if one stops absorbing the vitamin. The lack of B12 absorption usually results from: 1. a lack of B12 in the diet because of poor food selection; 2. a lack of intrinsic factor secretion due to aging, gastritis, or the partial removal of the stomach by surgery (gastrectomy); 3. lack of hydrochloric acid in the stomach, especially in the elderly; or 4. ileal resection or ileitis. Vitamin B12 d
Vitamin B12, or cobalamin, is one of the most important water-soluble vitamins since it is essential for blood cell production, DNA synthesis and to keep our nervous system functioning normally. It is generally stored in small amounts in our active body tissues like the liver, kidneys, heart, muscles and pancreas.