COBALAMIN (B12) Summary
Cobalamin, also known as vitamin B12, cannot be manufactured by humans and is obtained exclusively from the diet. Cobalamin is an enzyme cofactor for enzymes in energy metabolism and methylation/folate metabolism. Cobalamin has critical functions in the nervous system, including in the synthesis of myelin, and in the formation of red blood cells. Cobalamin deficiency is common, especially in individuals with vegan-like diets, gastrointestinal conditions, and/or autoimmune disease. Deficiency can result in anemia, functional symptoms (fatigue, weakness, lightheadedness), or neurological features (numbness or tingling, problems walking, psychosis, behavioral changes), which may be irreversible. Cobalamin is often used in the treatment of brain disorders like autism. It is also used to treat elevated levels of blood homocysteine, and as a general “energy” supplement. The form of cobalamin used in most nutritional supplements is cyanocobalamin, although other forms are preferred due to the lack of need to detoxify the cyanide component. Premium variants of B12 include adenosylcobalamin and hydroxycobalamin, which have more-direct action on enzymes. Side effects are rare at usual doses used in oral supplementation.