Increased risk of vitamin B12 deficiency is associated with deficiency of intrinsic factor and pernicious anemia; achlorhydria; atrophic gastritis; gastric carcinoma; gastrectomy, especially of the cardia or fundus; pregnancy and lactation: malnourished children; the elderly, especially those physically disabled and with urinary incontinence, tinnitus, or hearing loss; HIV injected individuals; psychiatric disorders; liver disease or cancer; Hrlicobacter pylori infection; intestinal diseases, especially involving malabsorption, such as celiac disease, Crohn’s
disease, colitis, chronic diarrhea (e.g., in AIDS), pancreatic disease, and tapeworms; vegan diets, especially over an extended period; chronic heavy cigarette smoking and/or alcohol use; excessive or prolonged use of medications such as antibiotics, anti- convulsants, cholestyramine, colchicine, gentamicin. metformin. neomycin, and para-aminosalicylic acid
(PAS); protracted intake of megadoses of vitamin C and copper.
Signs and Symptoms of B12 Deficiency
Depression, irritability, agitation, bone loss, confusion and memory loss (especially in elderly) fatigue, psychosis, classic pernicious anemia due to lack of intrinsic factor, macrocytic anemia, decreased phagocyte and polymoiphonucleocyte response, impaired lymphocyte response, poor blood clotting and easy bruising, progressive peripheral neuropathy, spinal
degeneration, unstable gait, decreased coordination, paresthesias loss of appetite, nausea, vomiting, glossitis, tongue and mouth irregularities, achlorhydia, dermatitis and skin sensitivity.
Complications associated with long-term depletion of this nutrient can take years to develop, and frank vitamin B12 deficiency is considered rare. Years of deficiency are usually required before hematological and neurological signs and symptoms become evident. Vitamin B12 deficiencies manifest primarily as anemia and neurological changes. Pernicious anemia is usually the first symptom of B12 deficiency and results from either inadequate intake or inhibited absorption associated with reduced gastric secretion of intrinsic factor.
Vitamin B12 deficiency, and subsequent impairment of cell replication in atrophy and inflammation of mucus membranes in the mouth and throughout the digestive tract, not only
results in reduced absorption of nutrients, gastric atrophy, anorexia, and weight loss, but also creates a gastric environment of increased susceptibility to imbalance and infection. Thus, numerous studies have observed a strong association between Hlicobacter pylori and B12 deficiency, even in the absence of gastric atrophy, with infection detected in 56% of individuals diagnosed with pernicious anemia in one trial. Likewise, inhibited DNA synthesis with B12 deficiency can lead to megaloblastic anemia and manifest as weakness, decreased ability to concentrate, and shortness of breath. Cobalamin-deficiency poly neuropathy is considered particularly difficult to diagnose, and deficiency for longer than 3 months can result in irreversible degenerative central nervous system (CNS) lesions, Low B12, levels may also be associated with an increased risk of brain disorders, birth defects, colon cancer, and heart disease. Vitamin B12, deficiency can mask signs of polycythemia vera.
Aged cheese such as fortified brewer´s yeast, roquefort, eggs, milk, oysters, salt- water fish, meat, and fish. All foods of animal origin, especially organ meats, provide vitamin B12, because it is produced by microbial synthesis in the digestive tract of animals, It does not occur in fruits, vegetables, grain, or legumes. A few foods of vegetable origin, specifically seaweed and micro-algae (including nori,chlorella, and spirulina) and tempeh, can
provide small but inconsistent amounts.