encyclopedia

Vitamin B12

Natural Sources:
Meat, fish, chicken, eggs and dairy products.

Forms:
Standardized Vitamin B12 supplements including liquid multi-vitamin and mineral products, capsules and tablets; ‘greens’ supplements; and fortified foods.

Therapeutic Uses:
– Aging Disorders

– Anemia (pernicious)

– Blood Disorders

– Brain Health

– Cellular Regeneration

– Depression

– Digestive Disorders

– General Debility

– Heart Health Maintenance

– High Homocysteine

– Immune System Health

– Infections

– Leg Cramps

– Low Energy

– Melancholy

– Nervous Disorders

– Senility

– Skin Disorders

– Vascular Disorders

– Vitamin B12 Deficiency (RDA = 2.0 – 6.0 mcg/day)

Overview:

Vitamin B12 (Cobalamin) is a fragile, water-soluble compound that performs a wide variety of functions in the body and is essential for good health. B12 is essential for normal nervous system function and normal red cell, white cell and platelet production. A deficiency of B12 in the diet, even a mild deficiency that is too subtle to show up in blood tests or to cause anemia, can result in neurological disorders and often mimics senility, dementia or Alzheimer’s disease. Vitamin B12 was first isolated in 1948 and immediately shown to be effective in the treatment of pernicious anemia. B12 also affects the maturation of all epithelial cells (cells that form the outer surface of the body and line inner passageways) and a deficiency may cause a false positive PAP smear. Recently, interest in the vitamin has been renewed because of the recognition that cobalamin deficiency occurs in 3% to 40% of the general population. Central nervous system problems may be irreversible if treatment is not initiated within 6 months of the onset of these symptoms. Vitamin B12 must become bound to a protein called intrinsic factor, secreted by cells in the stomach, before being absorbed by the body. However, intrinsic factor production by the stomach declines with age and the concomitant loss of B12 can result in pseudo-senility. B12 supplements significantly reduce the risk of deficiency. In a recent study of four hundred older people, 40% of non-vitamin takers had low B12 levels compared with only 12% taking a daily supplement (average 6 micrograms) – non-vitamin takers are thus 3.5 times more likely to be deficient in B12. There are two cobalamin-dependent enzymatic reactions that occur in humans that also strongly influence vascular health; deficiency in B12 inhibits these reactions and leads to an accumulation of homocysteine and methylmalonic acid (MMA).

Chemistry:
There are two commercial forms of B12: cyanocobalamin crystalline, which is available in the United States, and hydroxocobalamin crystalline, available in Europe. Enzymatic removal of the cyano group from cyanocobalamin is required to create the active molecule. Some medical researchers claim that cyanocobalamin sources from blue-green algae are actually inferior and can even exacerbate vitamin B12 deficiency. Others claim that algal sources are superior. In cases of severe vitamin B12 deficiency, it is best to seek the help of a trained medical professional.

Suggested Amount:
The latest Recommended Dietary Allowance (RDA) for vitamin B12 is 2.4 micrograms per day for persons aged 14 to 70 years; the average diet in the United States contains about 5 micrograms daily. Clinical trials involving positive results for treating leg cramps used B vitamin complex including 250 mcg of hydroxycobalamin daily. The liver contains most of the body’s cobalamin (about 1.5 mg), followed by the kidneys, heart, spleen, and brain. Normal body stores of vitamin B12 range from 2 to 10 mg; daily losses are 2 to 5 micrograms. Studies show that a more appropriate dosage for protection of older people is from 500-1000 micrograms of B12 daily. Note: In cases of severe deficiency resulting in anemia, it is recommended to use parenteral therapy or intranasal administration of cyanocobalamin or hydroxocobalamin followed by life-long supplementation of the diet. In Europe, intranasal hydroxocobalamin has been widely used for years. The intranasal administration of 500 micrograms of cyanocobalamin weekly attains blood levels that are comparable to those found with intramuscular injections.

Drug Interactions:
Certain drugs can interfere with the metabolism of vitamin B12.

Contraindications:
None known.

Side Effects:
There is no known toxicity of vitamin B12 according to medical researchers. Single doses of 100,000 micrograms and long-term dosages of 1000 mcg daily for five years caused no toxic reactions. However, some allergic skin reactions have been reported.

References:

Carper, J. 1995. Stop Aging Now. HarperCollins Publishers, 10 East 53rd Street, New York, New York 10022-5299. Pp. 68-72; 347-348.

Chan P, Huang TY, Chen YJ, Huang WP, Liu YC. 1998. Randomized, double-blind, placebo-controlled study of the safety and efficacy of vitamin B complex in the treatment of nocturnal leg cramps in elderly patients with hypertension. J Clin Pharmacol. 1998 Dec; 38(12): 1151-4.

Duke JA. 1992. Handbook of Biologically Active Phytochemicals and their Activities. CRC Press, Boca Raton, FL, p. 144.

Healton, E.B. 1991. Neurological aspects of cobalamin deficiency. Medicine (Baltimore) July 1991; 70(4): 229-245.

Wilson ML, Murphy PA. 2001. Herbal and dietary therapies for primary and secondary dysmenorrhoea. Cochrane Database Syst Rev. 2001; (3): CD002124. Review.

Additional Information:

Positive Clinical Trial Results on Treating Nocturnal Leg Cramps:

Nocturnal leg cramps are a common and troublesome problem in elderly individuals, and their etiology is unknown. Treatment with quinine is a common practice, but the effectiveness of the drug is doubtful and adverse drug effects are common. This randomized, double-blind, placebo-controlled study was conducted to evaluate the safety and efficacy of vitamin B complex capsules (fursulthiamine 50 mg, hydroxocobalamin 250 micrograms, pyridoxal phosphate 30 mg, and riboflavin 5 mg) in 28 elderly patients with hypertension who had severe nocturnal leg cramps that disturbed their sleep. Self-reported ratings of leg cramp frequency, duration, and intensity were used to evaluate severity of nocturnal leg cramps. Both the patients taking vitamin B capsules (n = 14) and those taking placebo (n = 14) received medications three times daily, and were examined regularly at 2-week intervals for 3 months. After 3 months, 86% of the patients taking vitamin B had prominent remission of leg cramps, whereas those taking placebo had no significant difference from baseline. Treatment with vitamin B complex significantly reduced the frequency, intensity, and duration of nocturnal leg cramps. Because quinine is not without potential for side effects, and vitamin B complex is a relatively safe and effective alternative, clinicians should reconsider the treatment of choice for nocturnal leg cramps.

Vitamin B12 Deficiency:

Vitamin B12 deficiency affects about one quarter of North Americans and is more common in the elderly and in adults with several predisposing conditions. Vitamin B12 deficiency is often undetected and can lead to devastating and irreversible complications. Symptoms of deficiency include: loss of appetite; diarrhea; numbness and tingling of hands and feet; paleness; shortness of breath; fatigue; weakness; sore mouth and tongue; depressed deep tendon reflexes; and confusion or dementia in severe or advanced cases. Diagnosis is easy with the help of many available laboratory tests. Early treatment is effective and prevents disability from anemia and neurological problems. There are several possible causes of vitamin B12 deficiency. The main causes include: dietary deficiencies (i.e. a strict vegetarian diet excluding all meat, fish, dairy products, and eggs), chronic alcoholism, abdominal or intestinal surgery that eliminates the site of intrinsic factor production or absorption, Crohn’s disease, other intestinal malabsorption disorders, fish tape worm, and pernicious anemia caused by a deficiency in the production of intrinsic factor. B12 deficiency anemia results in a decrease in the number of red cells in the blood. An elevated MMA level is viewed as the most specific marker for vitamin B12 deficiency except in chronic renal failure, in which MMA increases independently of B12 levels.