Vitamin B12 deficiency is known to cause blood abnormalities like megaloblastic anemia, a range of other physical problems like tremors, numbness, tingling of extremities and paralysis, and mental problems ranging from mild memory loss to dementia. Some other symptoms of deficiency in this vitamin manifest themselves as more of a cosmetic problem, namely an uneven darkening of specific areas of the body known as hyperpigmentation. Hyperpigmentation occurs most often on the backs of the hands and the tops of the feet, over the knuckles and on the finger and toe joints. It can also occur on the legs, armpits, in the back of the neck and even in the face. In this case the physical signs are an indication of the more serious medical problems described above. In a study of 21 patients who consulted a doctor for the hyperpigmentation problem, all of them were also found to be vitamin B12 (cobalamin)-deficient. Moreover, within weeks of vitamin B12 therapy, through injections initially and then through oral supplements, the vitamin B12 deficiency as indirectly measured by anemia and directly by looking the vitamin B12 levels in the serum, was relieved. The hyperpigmentation responded as well, visibly diminishing within 6-12 weeks of treatment.
These studies indicated that a considerable proportion of the human population is unable to absorb enough vitamin B12 through the diet to prevent deficiency symptoms from setting in. From the moment a person stopped taking in any vitamin B12 in the diet, it would take several years to develop a measurable vitamin B12 deficiency. The vitamin is stored in the liver and kidneys, and is reabsorbed from the bile, helping conserve it when intake is low. Although the usual sources to obtain the vitamin are meat and other animal products, vitamin B12 is produced by bacteria and some algae and enters our food chain through herbivores. It is a vitamin for all animals, so they all have to obtain vitamin B12 from their diets. As we get older, our capacity to absorb vitamin B12 from food decreases for various reasons. These include autoimmune reactions against the parietal cells in the stomach that secrete intrinsic factor, the glycoprotein that binds to cobalamin and escorts it into the cells of the small intestine. Stomach ulcers and the use of proton pumps will also have a negative effect on the parietal cells. Metformin, an ingredient in many medications for diabetics, hinders the absorption of the vitamin. Once through the small intestine, other protein carriers have to interact for the vitamin to get to its locations of action in the cellular cytosol and the mitochondria, and the older we are, the more likely that somewhere along the chain, a link will be missing.
It is a relief that whether vitamin B12 deficiency symptoms come from an imperfect diet or from our genes, they can be relieved by the administration of cobalamin, in a variety of forms. If your doctor diagnoses you with vitamin B12 deficiency, you will very likely be put on B12 injections, with high doses initially to counteract the deficiency, followed by an oral maintenance regimen. Since this vitamin is not toxic at all, some experts advocate taking large doses on a regular basis to prevent any of the problems mentioned above, and to help maintain homeostasis, the delicate balance between all our bodies’ systems.
