Among the vitamins, the vitamin B12, also called cyanocobalamin or B12 cobalamin possesses the largest chemical structure and is vital to many bio-chemical processes in the human body. This vitamin has a unique chemical structure among all the other vitamins, in that a metal, namely cobalt - is a vital structural component. Cobalamin was not successfully synthesized in the laboratory till the year 1972 due to the complex biochemistry.
The synthesis of nucleic acid and other biomolecules is regulated by cobalamin similar to the action of another vitamin - folic acid. The metabolism of folate itself is also influenced by cobalamin; moreover, this vital vitamin is necessary for the proper functioning and regulation of the nervous system and influences nerve cell structure.
A substance called the intrinsic factor must be present for the absorption of cobalamin to occur from the food present in the gastrointestinal tract - the absence of the intrinsic factor can result in very little cobalamin being absorbed from the gut. This substance called the intrinsic factor is a glycoprotein that all healthy stomachs secrete normally. The absorption of cobalamin is affected to a great degree by the intrinsic factor, for example, even very large doses of cobalamin - amounts exceeding more than 0.025 mg - can only be absorbed partially. The transport of this vitamin in the blood requires the presence of other proteins in the blood and its uptake at the cellular level is also governed by different groups of proteins. The name transcobalamines is given to these functional proteins.
The lack of the intrinsic factor and not a lack of the vitamin in the diet is the most common cause for a deficiency of the cobalamin - a disease called pernicious anemia. Large amounts of this vitamin are usually excreted by people suffering from pernicious anemia especially when it is given to them - this indicates that the vitamin is not being absorbed properly in the gut.
Using the cobalt found in food, most animals synthesize cobalamin in their bodies - more correctly, this synthesis is the work of the bacteria found in the gastrointestinal tract of most animals. A dietary source of the vitamin is essential for humans as the human body cannot normally synthesize this vitamin. Cobalt in human beings does not perform any function apart from being a structural component of the vitamin B12.
Physical symptoms seen during pernicious anemia can include problems such as generalized weakness, a sore and inflamed tongue, the presence of persistent numbness and tingling sensations in the extremities, general pallor and a weakened pulse, muscular stiffness, constant drowsiness, nervous irritability, long term depression and chronic diarrhea.
A deficiency of cobalamin even the most severe one may not necessarily result in pernicious anemia in the affected person. At the same time, a marginal deficiency may be expected to induce a much less extreme form of the physical symptoms just mentioned. The first thing to check in a person affected by such physical symptoms on a daily basis is the whether he or she suffers from some form of nutritional deficit - physical symptoms need not necessarily signal a deficiency of a vitamin.
At the same time, a deficiency of cobalamin can induce other kinds of symptoms; these can range from various mental problems to a greatly increased susceptibility to all kinds of infections and a vulnerability to various pathogens. Depending on one person to another, a lack of sufficient nutrients can also induce a greater vulnerability in certain organs or organ systems. As each person reacts differently to a deficiency of any nutrient, two individuals on a similar dietary regimen can be affected by totally different physical symptoms. At the same time, a third person eating the same diet may seem perfectly healthy and unaffected by the deficiency of the nutrient in the diet.
While this function is independent from the dementia normally associated with pernicious anemia, the vitamin cobalamin has another function with respect to mental health and seems to play an important role in the maintenance of mental health in humans. Cobalamin (vitamin B12) seems to be required in larger amounts by some people just to maintain a healthy nervous system. Such people can be adversely affected by a severe deficiency of the vitamin, and such deficiencies can easily land them in the mental hospital, similarly, a marginal deficiency will be sufficient to make them difficult to deal with and may affect their relationships due to the impairment of normal psychological processes.
The main impairment suffered by a person affected by a cobalamin (vitamin B12) deficiency is an impairment in the activity of the immune system, this occurs primarily by the inhibition of the leukocytes - these are the white and clear protective blood cells found in all human blood. In individuals affected by this symptom, the process of phagocytosis, which is the envelopment of invading pathogenic organisms by the leukocytes, was lowered to slightly more than one third of what normally took place. The rate at which bacteria were eliminated was also lowered. These symptomatic effects were reversed on supplementation with the vitamin.
Cobalamin is found in high amounts in all kinds of organ meats. Moderately good sources for this vitamin include all muscle meats and fish, somewhat smaller amounts are also found in milk and other dairy products. Cobalamin is also found in some types of vegetable, particularly plants from the sea - such as different kinds of seaweeds (example wakame and kombu) as well as in fermented legumes like soybeans - tempeh. Cobalamin is also found in nutritional yeast as a cobalamin fortified base can be used to grow different strains of yeast. Synthesized cobalamin can also be used to fortify the base on which certain types of yeasts are grown. Light, acids and alkalis can degrade cobalamin. Cooking does not normally degrade the cobalamin found in food, though overheating foods can destroy most of the vitamin found in the food.
A wide variety of supplements of cobalamin are available in the market, these dosages range from a few micrograms up to a milligram or 1000 micrograms per dose.
A deficiency of cobalamin tends to affect vegans - extreme vegetarians who avoid even dairy products and eggs, even though the deficiency can take many years to fully develop in the body of a vegan. In addition, a deficiency of cobalamin tends to affect people with malabsorption disorders. High dosages of the vitamin B12 in supplemental form are often a requirement of individuals who suffer from pernicious anemia. An increased risk of developing a deficiency of the vitamin B12 is also evident in older people suffering from urinary incontinence or loss of hearing.
Infants have an RDA for cobalamin at 0.5 micrograms - 0.0003 mg while women in a term of pregnancy need 4 micrograms - or an RDA of 0.004 mg. The general RDA for all other healthy adults is 3 micrograms of the vitamin a day. Therapeutically used doses of this vitamin are much higher than the RDA ranges. Supplementation or an improvement in the diet will correct a deficiency of the vitamin due to a poor diet. At this time, a lack of the intrinsic factor or a defect in the metabolism of the vitamin seems to be the two reasons for most of the deficiencies. The only way to correct the deficiency in such situations is to take the intrinsic factor along with any supplement of the vitamin, or to have the vitamin directly injected in the body in order to bypass the faulty absorption of the vitamin from the gut. One of these treatments may be required on a life long basis by individuals who have such a metabolic defect - until and unless some way is found to rectify the metabolic defect.
The use of supplemental vitamin B12 does not induce any known side effects even at relatively high doses.
Folic acid supplements taken at or above 1,000 mcg daily can substantially alleviate anemia induced by a deficiency of the vitamin B12 - but this supplement will not affect the major neurological symptoms due to the deficiency of cobalamin. The supplements of folic acid provide a partial solution to one symptomatic problem seen during B12 deficiency, folic acid at these high doses does not generate toxic effects in the body. At the same time, these folic acid supplements will not alleviate all the other symptomatic disorders seen during a deficiency of the vitamin B12 - most of them are neurological and affect the psychological state of the person.
Even in individuals who do not require folic acid supplements, a deficiency of vitamin B12 does not necessarily imply anemia. This fact that a B12 deficiency does not necessarily imply anemia is unknown to some doctors - a factor that can contribute to misdiagnosis. The patient may suffer irreversible bio-chemical damage if this misdiagnosis delays the correct identification of a vitamin B12 deficiency. If the doctor is proficient and uses the proper testing procedures, than this very rare problem is unlikely to occur as misdiagnosis will be avoided.
A doctor of natural medicine must first evaluate any one who plans to supplement with more than 1,000 mcg daily of folic acid to avoid the problem - such supplemental regimens must be supervised.