VITAMIN B12 (Cyanocobalamin, Hydroxycobalamin)

Vitamin B12 an essential water-soluble nutrient belonging to the B COMPLEX that is required in extremely minute amounts for cell division and growth Vitamin B12 is unique in several respects: It is the only B vitamin stored in the body and the only known nutrient to contain the trace mineral COBALT. Like all B vitamins, vitamin B12 must be chemically modified to form a coenzyme (enzyme helper) before it can participate in metabolism. Vitamin B12 has important, though very limited, roles III metabolism. It assists in the utilization of single carbon (methyl) groups transfer from the amino acid, methionine, to donors, including thymine, a building block for DNA. Vitamin B12 also helps to oxidize certain fatty acids and it supports the maintenance of healthy nerves. With deficiencies possible irreversible brain damage and nervous disorders can occur.

The body has evolved an efficient mechanism to absorb this vitamin. To begin the process, the stomach normally secretes INTRINSIC FACTOR, a protein that binds vitamin B12 and carries it to the INTESTINE where it aids B12 absorption. An estimated 20% of people in their 60s and 40%, of people in their 80s develop atrophic gastritis, in which the stomach does not produce enough acid and intrinsic factor. With inadequate stomach acid to sterilize the stomach, certain bacteria can grow; consuming the vitamin that otherwise would be absorbed by the intestine. Vitamin B12 together with another B vitamin, FOLIC ACID, functions in DNA synthesis and cell division, and supports red blood cell production. A large dose of folic acid to treat anemia can mask a vitamin B12 deficiency; folic acid often is; administered with B12.

Possible Roles in Maintaining Health

Anemia: A deficiency of intrinsic factor causes PERNICIOUS ANEMIA, a disease caused by inadequate B12 absorption despite adequate dietary supplies.

Nervous disorders Mental deterioration, SENILITY and neuropsychiatric disorders-including dementia, DEPRESSION and loss of balance-may respond to extra vitamin B12. An estimated 10% of elderly persons have marked vitamin B12 deficiencies, and many patients with senile dementia are B12-deficient. Vitamin B12 may help in the treatment of chronic fatigue and age-related decline in energy level and well being.

Cigarette smoking Smokers have low vitamin B12 and folic acid levels. Preliminary clinical studies suggest that supplementation with both vitamins reduces the amount of precancerous bronchial tissue.

Chronic pain Vitamin B12 has been used to treat bronchial spasm (ASTHMA), bursitis and bone spur pain. Neuralgia pain radiating along nerves may respond to intramuscular infections of vitamin B12.

Wound healing Anecdotal evidence from both patients and physicians suggests that certain individuals are helped by supplemental vitamin B12 to recover more rapidly from illness and surgical procedures.


Vitamin B12 occurs mainly in animal products—MEAT, POULTRY, FISH, EGGS and SHELLFISH. Some fortified foods like nutritional yeast contain vitamin B12. Tamari, tempeh and miso were found to be essentially lacking in this vitamin, although sometimes these foods are claimed to be rich sources of the vitamin. SPIRULINA contains much less usable vitamins than formerly believed; the amount in seaweed is variable. Part of the problem seems to be that seaweed contains B12 analogs that do not form coenzymes in the body. Therefore strict vegetarians (those who eat no animal products) may need to support their diet with vitamin B12 supplements.


The RECOMMENDED DIETARY ALLOWANCE (RDA) for vitamin B12 for normal adults is 1000 to 2000 mcg daily. Severe vitamin B12 deficiency is rare. Newer, more sensitive laboratory blood tests and metabolic indicators have turned up low-level B12 deficiencies with surprising frequency. Those who are most likely to be deficient include strict vegetarians; elderly persons; alcoholics; patients with CROHN’S DISEASE, severe food allergies or chemical sensitivities; and people who have undergone stomach surgery or who have a family history of anemia. About 5% of adults over the age of 50 have low vitamin B12 levels. Half of these may have difficulty in absorbing the vitamin from food. Low folic acid intake and some antibiotics interfere with vitamin B12 uptake. People suffering from anxiety or depression who take antidepressants (tricyclics and chlorpromazine) may block vitamin B12 uptake.

Signs of vitamin B12 deficiency include weakness in the arms and legs, difficulty in walking, and even paralysis. Irreversible nerve damage is possible. Prolonged vitamin B12 deficiency causes neurological symptoms and anemia. Injections of this vitamin clear up pernicious anemia. Vitamin B12 is not toxic when taken orally. Nasal or sublingual (under the tongue) vitamin B12 gels or vitamin injections are effective for vegetarians and for those with malabsorption problems. There is no known toxicity associated with this vitamin when taken orally. Often, elevated vitamin B12 in the blood is most readily obtained through B12 injections. Occasionally some people are allergic to injections, but this is usually due to the preservative in the injection liquid.

I have found clinically that probably 75% of American females are anemic. The best protocol I have researched and found that works the best in treating this anemia is to have the patient receive 2.5cc of vitamin B12 intramuscular injection twice weekly for 6 weeks. Then the patient can switch to a sublingual vitamin B12 2000mcg tablet 3 times weekly thereafter, if prone to anemia.

SEE ALSO: COBALT in the mineral section

Lindenbaum, J., et al., “”Neuropsychiatric Disorders Caused by Cobalamin Deficiency in the Absence of Anemia or Macrocytosis,,” New England Journal of Medicine, 318:26 (1988), pp. 1720-28.

Naurath, Hans J., et al., “‘Effects of Vitamin B12, Folate and Vitamin B6 Supplements in Elderly People with Normal Serum Vitamin Concentrations,” Lancet, 346 (July 8, 1995), pp. 85-89.

Vitamin B12 for chronic fatigue syndrome

The Cheney Clinic has administered vitamin B12 (cyanocobalamin) to a large number of patients with chronic, fatigue syndrome (CFS). The usual dose was 2,500 to 5,000 mcg given subcutaneously or intramuscularly, every 2-3 days. The solution used contained vitamin B12 at a concentration of either 3,000 or 5,000 mcg/ml. Approximately 50-80% of the patients improved with this therapy. A minimum dose of 2,000 to 2,500 mcg per injection was usually needed to produce a response. Some patients improved after the first injection, but the majority did not improve until they had been receiving injections for weeks. Typically, an increase in energy, stamina or well-being was noted within 12 hours of receiving the injection and the effects usually wore off within 2-3 days. In some cases, the treatment stopped working after a period of time. However, when the injections were discontinued for a few weeks and then resumed, they were again beneficial. Oral or intra-nasal vitamin B12 preparations were not effective. Some patients using the highest doses developed an acneiform rash which disappeared when the dose was reduced.

COMMENT: The mechanism by which vitamin B12 relieves fatigue is not known. However, a “tonic” effect of this vitamin has been demonstrated previously in a double-blind placebo–controlled study (Br J Nutr 1973; 30:277-283) Although vitamin B12 therapy probably does not address the cause of CFS, the treatment is safe and it can help patients function better. High dose vitamin B12 should therefore be considered for patients suffering from CFS. Lapp CW, Cheney PR. The rationale for using high-dose cobalamin (vitamin B12). CFIDS Chronicle Physicians’Forum, Fall, 1993. pp. 19-20.

VITAMIN B12 – Reference List