Cobalamin is a group of enzymes based on cobalt that are collectively known as the B12 vitamins. Four cobalamins are used by humans: cyanocobalamin, hydrocobalamin, methylcobalamin and adenosylcobalamin.
Cyanocobalamin is synonymous with vitamin B12 in most peoples' minds. It is the cobalamin form that is found in meat and meat products, and most cobalamin supplements in the US are cyanocobalamin.
Hydrocobalamin is the cobalamin used in Europe to treat vitamin B12 deficiency. Hydrocobalamin is also used both in the US and in Europe to treat cyanide poisoning. Hydrocobalamin combines with the excess cyanide to form cyanocobalamin, which can be either stored or excreted.
Neither cyanocobalamin nor hydrocobalamin is in a form our bodies can use. They must be converted to the usable forms of cobalamin: methylcobalamin and adenosylcobalamin. In addition to other metabolic functions, each form of cobalamin is necessary for a specific co-enzyme to work. MUT needs methylcobalamin to work, and MTR needs adenosylcobalamin to work.
Even though we can convert one form cobalamin to another, our bodies cannot synthesize it. We must either get cobalamin in food or take cobalamin supplements. There are several reasons to use cobalamin supplements.
Some people-notably vegans and vegetarians-have cobalamin-deficient diets. Plants do not contain usable cobalamin. Some vegan foods contain cobalamin-like substances, but they cannot be used by humans. Vegetarians often don't get enough cobalamin from the milk and eggs they eat, and studies have demonstrated that a large majority of vegetarians suffer from cobalamin deficiency. Vegans and vegetarians definitely benefit from cobalamin supplements.
Under the best circumstances, humans are poor absorbers of cobalamin. Most of the cobalamin we eat travels unchanged through our digestive system and is excreted. Almost all of the cobalamin we do absorb is bound to intrinsic factor, which is secreted by the stomach. Cobalamin binds with intrinsic factor and the cobalamin-intrinsic factor complex moves through the intestine to the upper ileum, where it is absorbed.
Problems with intrinsic factor can prevent adequate cobalamin absorption. Some people have a genetic lack of the enzyme necessary to make intrinsic factor. Frequently, people develop an autoimmune response to intrinsic factor and make antibodies against it. Intrinsic factor antibodies may also attack the cobalamin-intrinsic factor complex in the blood, and keep it from functioning. This may be why some people have symptoms of cobalamin deficiency even when they have normal serum B12 levels.
Malabsorption can also cause cobalamin deficiency. Surgery that affects the gastrointestinal tract may impair absorption of cobalamin. Inflammatory bowel disease can also affect cobalamin absorption.
People who have problems getting enough cobalamin benefit from taking cobalamin supplements. Obviously, if you have trouble absorbing cobalamin, taking cobalamin pills may not provide as much as you need. The B12 Patch provides cobalamin reliably through the skin, and may be the answer for you.
