Vitamin B-12, also called cobalaminm (for the cobalt content), is a water soluble vitamin instrumental in the functioning of blood production, and the brain and nervous system and active in the metabolism of all cells affecting fatty acid synthesis, and most importantly, DNA formation and regulation
B12 is obtained through foods that are a natural source, or are otherwise fortified. Natural food sources include fish, meat, poultry, eggs, milk, and milk products, and those fortified are typically cereals, yeast, soymilk, and energy bars. Because of the natural and fortified sources of B12 existing within animal products, vegans, who ingest no foods that have any animal product in them including eggs and dairy, these individuals are at an alarming risk for the deficiency. Supplementation, however, is manufactured via bacteria, not animal sources and so it is an option for these individuals to supplement B12.
B12 is absorbed through the secretions of the parietal cells of the gastrointestinal tract, called intrinsic factor. Any reduction or impairment of these cells creates a risk for the development of vitamin b12 deficiency and subsequent more severe conditions. B12 deficiency and related causes are primarily attributed to the discovery of pernicious anemia in which the parietal cells of the stomach are destroyed via an autoimmune response resulting in impaired secretion of intrinsic factor necessary to facilitate B12 absorption. Thus, most causes of this deficiency surround impaired absorption from a variety of factors as well as insufficient dietary intake.
Selective impaired absorption of vitamin B12 due to intrinsic factor deficiency can result from parietal cell reduction associated with chronic atrophic gastritis seen in many elderly individuals, on resection of stomach through bariatric surgery.
Impaired absorption of vitamin resulting from malabsorption can include structural damage, small bowel removal sometimes resulting from Crohn’s disease, other types of intestinal resection, especially the terminal ileum where B12 absorption is highest, achlorhydria, which may be precipitated by the use of prescription proton pump inhibitors, or acid reducers given to individuals suffering from gastrointestinal esophageal reflux disease, or GERD.
There are also associated causes stemming from hereditary conditions, some diabetic medications, parasitic infections, alcohol abuse, and abuse of nitric oxide.
Symptoms of low grade deficiency are nonspecific and include poor memory, fatigue, depression, and anemia. At greater levels of deficiency, neurological symptoms manifest as a result of the crucial role B12 plays in the function of brain and nervous tissue and can cause severe and irreversible neurological damage. The symptoms of nervous system involvement include decreased perception of touch, decreased muscle reflexes, intermittent episodes of asymmetric weakness or paralysis, and are sometimes associated with the onset of some psychological conditions such as bipolar disorder, paraphrenic states, and suicidal tendencies.Vitamin B-12 Products