Vitamin B12 — Cobalamin

Vitamin B12 (Cobalamin) is named the “red vitamin,” as it is a red crystalline compound.
B12 is unique in that it is the only vitamin that contains an essential mineral–namely, cobalt. Cobalt is thereby needed to make B12 and so is essential for health. B12 is unique also in that it is required in much tinier amounts than the other B vitamins. Only 3-4 mcg. (micrograms, or thousandths of a milligram) are needed at minimum; however, higher levels, up to 1 mg., are often used therapeutically.

Vitamin B12 is a very complex molecule. Besides cobalt, it also contains carbon, oxygen, phosphorus, and nitrogen. Cobalamin is stable to heat, though sensitive in heated acid or alkali solution, slightly sensitive to light, and destroyed by oxidizing and reducing agents and by some heavy metals.

Vitamin B12 was isolated in 1926 as the factor that treated a feared disease, pernicious anemia–termed “pernicious” because it could be fatal, most often from neurologic degeneration. But the substance cobalamin, when given orally (actually liver was used as the cure; it contains high amounts of B12), did not cure all of the people with the disease, and some people still developed pernicious anemia. It was later found that a mucoprotein enzyme produced by the stomach (by the parietal cells that also make hydrochloric acid) was also needed for vitamin B12 to be absorbed into the body from the intestines. This enzyme has been termed the “intrinsic factor,” while vitamin B12 is the “extrinsic factor.” Aging, stress, and problems with the stomach or stomach surgery weaken the body’s ability to produce the “intrinsic factor”; also, some people appear to have a genetic predisposition that makes them more prone to pernicious anemia. Hydrochloric acid helps the absorption of B12; if acid production is weak, the absorption is lessened. Calcium and thyroid hormone assist as well. Pregnancy, absorb this important vitamin. Aging more
likely lessens some of the many factors needed for ideal absorption of B12, so deficiency symptoms are more common in older people.

Cobalamin is absorbed primarily from the last part of the small intestine, the ileum. In the blood, it is bound to a protein globulin to be carried to the various tissues. The body actually stores vitamin B12, so any deficiencies may take several years to develop. The
highest concentrations of B12 are found in the liver, heart, kidney, pancreas, brain, testes, blood, and bone marrow–all active metabolic tissues. The “red vitamin” is very important to the blood.

Cobalamin is made in nature by microbial synthesis–produced by bacteria in the intestinal tracts of animals and stored in their tissues. Some B12 is made during fermentation of foods as well. Cobalamin is the naturally occurring vitamin B12. Cyanocobalamin, as B12 is often known, is actually the commercial variety of B12 and contains a cyanide molecule attached to the cobalt. B12 is not synthesized but, like penicillin, must be grown in bacteria or molds and then processed. Other forms of B12 include hydroxycobalamin (technically, vitamin B12a), aquacobalamin (vitamin B12b), and nitrocobalamin (vitamin B12c).

Sources: Vitamin B12 is found in significant amounts only in the animal protein foods.
B12 is also manufactured by bacteria in the human intestines, but it is not known how much we can naturally absorb and utilize from that source. In general, digestion and absorption must be good for adequate B12 to be obtained. Many laxatives and overuse of antacids can reduce absorption and deplete stores of B12.

Our primary food sources of vitamin B12 include meat, most fish, especially the oily ones (trout, herring, and mackerel), crabs and oysters, eggs (the yolk), and milk products, especially yogurt. Organ meats such as liver, heart, and kidney are particularly high. The vegan–that is, the strict vegetarian who consumes no animal-source foods–is not getting the necessary vitamin B12 from diet (although tempeh, a fermented soybean product, and some sprouts may contain some vitamin B12); thus, vegans will often need an additional supplement (which absorbs well) or periodic injections.

Functions: Although vitamin B12, cobalamin, apparently does not have as many functions
as some of the other B vitamins, it has some very important ones. It is essential for the metabolism of the nerve tissue and necessary for the health of the entire nervous system. It stimulates growth and increases appetite in children. Cobalamin, along with iron, folic acid, copper, protein, and vitamins C and B6, is needed for the formation of normal red blood cells.

Vitamin B12 is the “energy” vitamin, as it often increases the energy level, whether obtained from eating the B12 foods or from supplemental use. There may be several reasons for this. Cobalamin stimulates the utilization of proteins, fats, and carbohydrates. It also helps iron function better in humans and is important for the synthesis of DNA and RNA, as well as for production of choline, another B vitamin, and methionine, an amino acid.

Uses: Vitamin B12 is generally known as the longevity vitamin, possibly because it helps
the energy level and activity of the nervous system of the elderly. B12 injections (the main therapeutic use of this vitamin) have been a common practice of many doctors for the treatment of fatigue, and, in my experience, it works very often. However, it would only be a “cure” when the tiredness is a result of B12 deficiency. There are many reasons for fatigue. As we age, our digestion and absorption are not usually as finely tuned as when we were young, particularly when we eat and live the way most of us late twentieth-century beings do. And vitamin B12, even though it is needed in such small doses, is one of the most difficult vitamins to acquire through diet and to metabolize. The “red vitamin” is the main “antifatigue” vitamin; often given along with folic acid, it helps energy and prevents most anemia, provided there is good iron absorption and hydrochloric acid production.
Medically speaking, it is wise to check patients with fatigue for anemia and to measure vitamin B12 and folic acid levels before embarking on a treatment regimen.

B12, given intramuscularly, usually in doses of 500-1,000 mcg. (0.5-1.0 mg.), is used once, twice, or three times weekly for a period of time to both give energy and, in adults, help with appetite suppression in weight loss programs. These amounts also replenish the vitamin B12 stores. It has a mild diuretic effect as well and may be used premenstrually to diminish water retention symptoms.

In the treatment of pernicious anemia and the earlier symptoms of vitamin B12 deficiency, injections of cobalamin or its variants are usually necessary because most everyone with deficiency has poor absorption. It is difficult to become B12 deficient from diet alone, unless we are on a strict vegan diet for years. In any anemia, really, it is wise to supplement B12, because it helps the red blood cells develop to a point where protein, folic acid, iron, and vitamin C can then complete their maturation so that we can better carry oxygen and energy to all of our cells.

Vitamin B12 will stimulate growth in many malnourished children. In older people, it has helped with energy levels as well as psychological symptoms, including senile psychosis. B12 has also been used to help treat osteoarthritis and osteoporosis and for neuralgias, such as Bell’s palsy, trigeminal neuralgia, or diabetic neuropathy. It has likewise been used in the treatment of hepatitis, shingles, asthma, other allergies, allergic dermatitis, urticaria, eczema, and bursitis. Cobalamin has been used for many other symptoms besides fatigue, including nervousness and irritability, insomnia, memory problems, depression, and poor balance. Vitamin B12 is something to keep in mind when we are not “feeling our oats.”

Deficiency and toxicity: There have been no known toxic effects from megadoses of
vitamin B12. Thousands of times more than the RDA have been injected both intravenously and intramuscularly without any ill consequences. On the contrary, there is often some benefit.

Vitamin B12 deficiency usually results from a combination of factors. Restricted diets, as seen in vegetarians or poor nations, can be very limited in B12. Since the absorption into the body is so finely tuned, depletion and deficiency occur even more commonly from poor digestion and assimilation, or from deficient production of intrinsic factor. That is why it is so important to be aware of B12 and use some sort of supplementation once a deficiency has been diagnosed. Vitamin B12 blood levels, along with folic acid levels, are the most common vitamin tests performed by doctors. As we age, it is more likely that we may become B12 deficient. Also, alcoholics and people with malabsorption or dementia may have low B12 levels. Since the body stores vitamin B12, it may take several years to become deficient with dietary restriction or a decrease in intrinsic factor.

The strict vegetarian has more concern than the average meat- and dairy-eating person. B12 is not found in the vegetable kingdom other than in foods fermented by certain bacteria; thus most fermented foods have some vitamin B12. However, in vegetarians, there is usually a high folic acid intake, and since folic acid and B12 work similarly in the body, a B12 deficiency may be masked for a period of time, and then more pronounced symptoms may occur. If B12 is deficient in an animal eater, then we pretty much know there is a problem in absorption of the vitamin.

Most problems of B12 deficiency affect the blood, energy level, state of mind, and nervous system. Often, subtle symptoms may start with the nervous system. Vitamin B12 nourishes the myelin sheathes over the nerves, which help maintain the normal electrical conductivity through the nerves. Soreness or weakness of the arms or legs, decreased sensory perceptions, difficulty in walking or speaking, neuritis, a diminished reflex response, or limb jerking may result from B12 deficiency. Psychological symptoms may include mood changes with mental slowness may be one of the first symptoms.

With B12 deficiency, the body forms large, immature red blood cells, resulting in a “megaloblastic” anemia. Pernicious anemia refers to the deficiency in blood cells as well as the myriad of psychological and nerve symptoms. The anemia usually generates more fatigue and weakness. Menstrual problems, even amenorrhea (lack of menstrual flow), may also occur in B12-deficient women.

The problems related to the nervous system caused by vitamin B12 deficiency can lead to permanent damage, not correctable by B12 supplementation. This irreversible nerve damage may occur when the B12 deficiency effect on the red blood cells is masked by adequate levels of folic acid, as I mentioned. More severe pernicious anemia can cause a red, sensitive tongue, referred to as “strawberry tongue,” which may even ulcerate, and nerve or brain and spinal cord degeneration, which can cause weakness, numbness, tingling, shooting pains, and sensory hallucinations. Paranoid symptoms may even occur. In the early part of this century, pernicious anemia was often a fatal disease.

Requirements: Vitamin B12 is essential but required only in minute amounts; 3-4 mcg. is
needed in most adults to prevent deficiency, and at least that amount is required by pregnant or lactating women, as well as infants and growing children. From 10-20 mcg. daily is a good insurance level, although certain people may need increased amounts with higher protein intake. Vitamin B12 is often taken in higher doses, 500-1000 mcgs. per day, to relieve fatigue. Injections of B12 in these amounts are used to treat a variety of low-energy and mental symptoms previously described as well as during some weight loss programs. When there is fatigue or anemia, it is a good idea to get the blood level of B12 checked by a doctor. It may lead to a very simple and successful treatment.

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Elson M. Haas MD Written by Elson M. Haas MD

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