Vitamin B12 is only synthesized by microorganisms in nature and thus, is obtained by human beings through their diet. Since the most important source of vitamin B12 is animal proteins, vegetarians may lack sufficient quantities of this vitamin in their diets. Vitamin B12 deficiency may stem from a lower dietary intake, an autoimmune issue related to intrinsic factors or gastrointestinal system diseases resulting in vitamin B12 malabsorption. The most important symptoms and findings of severe vitamin B12 deficiency are anemia and neurological problems. If it is not treated, anemia symptoms and neurological disturbances resulting in spinal cord and cerebral cortex demyelination may emerge. Vitamin B12 deficiency is one of the most frequent vitamin deficiencies worldwide. This deficiency is a highly important public health issue because of its serious complications if it is not detected and treated appropriately, although its treatment is very simple. Epidemiological studies in this field are, therefore, of great value. Most of the studies on this subject have been examined vitamin status of the general population. The research generally contains to the national or provincial populations data. Nevertheless, the few data are not fully representative in the general population. Determining risk factors and at‐risk groups, and educating them about vitamin B12 deficiency and proper diet would prevent the irreversible complications of this type of deficiency. The goal of this study is to review epidemiological studies related to vitamin B12 deficiency and to point out the importance of identifying and treating it.
Part of the book: Epidemiology of Communicable and Non-Communicable Diseases