Vitamin B12 is the most chemically complex of all of the vitamins, and is actually the name for a group of compounds known as cobalamins. The cobalamins act similarly in the blood to hemoglobin, except that instead of iron they contain cobalt. Vit B12 comes in several forms, but not all of the forms are equally effective. The most effective form is methylcobalamin. However, the most common form is cyanocobalamin, because it is easier to manufacture, and is therefore less expensive.
The very common and inexpensive cyanocobalamin is difficult for the body to absorb, and the small amount that is absorbed usually fails to make it into the cells where the body can utilize it. Small amounts of cyanocobalamin are converted to methylcobalamin in the liver, but the body requires much larger amounts than the liver can convert in order to maintain normal body function. As a result of this, even people who take large amounts of the less expensive form of vit B12 continue to be deficient. These people often find themselves resorting to vit B12 injections, which are only available from a doctor by prescription, when they actually would be OK if they switched to taking the methylcobalamin either in pill form or sublingually (under the tongue). Those people with severe digestive disorders may have no choice but to take the vit B12 injections.
Methylcobalamin plays an important role in the growth and protection of the nervous system. Vitamin B12 deficiency due to malabsorption is most common in elderly people. Larger doses are especially important to help fight against neurological deterioration as we age.
From here on out, as we talk about vit B12, we will be considering it to be the methylcobalamin form. This form of vit B12 may help prevent Parkinson's disease, and slow its progression in those who already have it. This vitamin also shows promise in the treatment of multiple sclerosis and other neurological diseases. Very few substances are known to have any positive impact on the regeneration of nerves in the human body. However, a 1994 study in the Journal of Neurological Science showed that very high doses of the methylcobalamin form of vit B12 produced nerve regeneration in rats.
Vitamin B12 plays an important role in building the protein necessary for cardiovascular function. It is also needed by the body to prevent anemia. It works along with folic acid in regulating the formation of red blood cells, and helps with the utilization of iron. This vitamin is also required for proper digestion and the absorption of foods, and the proper metabolism of carbohydrates and fats. It also aids in cell formation and cellular longevity. Vit B12 also prevents nerve damage, maintains fertility, and promotes normal growth and development by maintaining the fatty sheaths that protect nerve endings.
Vitamin B12 is also linked to the production of acetylcholine, a neurotransmitter that assists with memory and learning. Vit B12 supplementation has been shown to enhance sleep patterns, allowing for more restful and refreshing sleep.
A 2004 study reported in the American Journal of Obstetrics and Gynecology found that women who gave birth to children with spina bifida had vit B12 levels that were 21 percent lower than those of mothers who had healthy children.
Vitamin B12 deficiency can be caused by malabsorption, and is most common in older adults and people with digestive disorders. Symptoms associated with vit B12 deficiency can include abnormal gait, bone loss, chronic fatigue, constipation, depression, digestive disorders, dizziness, drowsiness, enlargement of the liver, eye disorders, hallucinations, headaches (including migraines), inflammation of the tongue, irritability, labored breathing, memory loss, moodiness, nervousness, neurological damage, palpitations, pernicious anemia, ringing in the ears, and spinal chord degeneration.
The largest amounts of vit B12 are found in meats, brewer's yeast, clams, eggs, herring, kidney, liver, mackeral, milk and dairy products, and seafood. Vit B12 is not found in many vegetables; it is found only in sea vegetables, such as dulse, kelp, kombu, and nori, and soybeans and soy products.
Herbs which contain vit B12 include alfalfa, bladderwrack, and hops.
Strict vegetarians must remember that they need vitamin B12 supplementation, as this vitamin is found almost exclusively in animal tissues. People who follow a strictly vegetarian diet may not see any signs of the deficiency for a long period of time, as the body can store up to a five year supply of vit B12. However, signs will eventually develop.
Antigout medications, anticoagulant drugs, as well as potassium supplements may block the absorption of vit B12 in the digestive tract. Taking vit B12 in sublingual tablets, which are dissolved under the tongue instead of swallowed, can be a good alternative for people who have difficulty absorbing it.
Intrinsic factor is a protein which is produced in the gastrointestinal tract that is necessary for the absorption of vit B12. People who lack intrinsic factor in their systems will require the use of sublingual forms or injections to insure proper absorption of this vitamin.
There is a blood test, called the Schilling test, which can be used to determine the body's ability to absorb vit B12.
There are still some health food stores that do not stock the methylcobalamin form of vitamin B12 at this time. We expect, however, that as the research on this nutrient becomes more widely known, it will become easier to find under various brand names.
This information is not intended to diagnose or treat any specific condition, nor is it intended to replace the advice of your healthcare professional.
Sources
Balch, Phyllis A., CNC. "Prescription for Nutritional Healing". Garden City, NY.: Avery Publishing Group, 2006
Ritchason, Jack, ND. "The Little Herb Encyclopedia". Pleasant Grove, UT.: Woodland Health Books, 1995
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