Cobalamin-Vitamin B12
Vitamin B12, also called cobalamin, is one of 8 B vitamins. All B vitamins help the body convert food (carbohydrates) into fuel (glucose), which is "burned" to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body metabolize fats and protein. B complex vitamins are necessary for healthy skin, hair, eyes, and liver. They also help the nervous system function properly.

All B vitamins are water-soluble, meaning that the body does not store them. Vitamin B12 is an especially important vitamin for maintaining healthy nerve cells, and it aids in the production of DNA and RNA, the body's genetic material. Vitamin B12 also works closely with vitamin B9 (folate) to regulate the formation of red blood cells and to help iron function better in the body. Folate and B12 work together to produce S-adenosylmethionine (SAMe), a compound involved in immune function and mood. Vitamins B12, B6, and B9 work together to control blood levels of the amino acid homocysteine. High levels of homocysteine are associated with heart disease. Mild deficiencies of B12 are not uncommon in elderly people, either because of poor diet or because they have less stomach acid, which the body needs to absorb B12. Low levels of B12 can cause a range of symptoms including fatigue, shortness of breath, diarrhea, nervousness, numbness, or tingling sensation in the fingers and toes. Severe deficiency of B12 causes neurological damage.
Methylcobalamin is the neurologically active form of vitamin B12

Others at risk for B12 deficiency include:
arw Vegans (vegetarians who also don't eat dairy or eggs)
arw People with malabsorption conditions, such as tapeworm infection, pancreatic disease, and conditions resulting from gastrointestinal surgery.
People who are infected with Helicobacter pylori (an organism in the intestines that can cause an ulcer). H. pylori damages stomach cells that make intrinsic factor, a substance the body needs to absorb B12.
arw People with an eating disorder.
arw People with HIV.
arw The elderly because our ability to absorb vitamin B12 diminishes as we age.

What is Cobalamin ?
Vitamin B12 (cobalamin) is an important water-soluble vitamin. In contrast to other water-soluble vitamins it is not excreted quickly in the urine, but rather accumulates and is stored in the liver, kidney and other body tissues. As a result, a vitamin B12 deficiency may not manifest itself until after 5 or 6 years of a diet supplying inadequate amounts. Vitamin B12 functions as a methyl donor and works with folic acid in the synthesis of DNA and red blood cells and is vitally important in maintaining the health of the insulation sheath (myelin sheath) that surrounds nerve cells. The classical vitamin B12 deficiency disease is pernicious anaemia, a serious disease characterized by large, immature red blood cells. It is now clear though, that a vitamin B12 deficiency can have serious consequences long before anaemia is evident. The normal blood level of vitamin B12 ranges between 200 and 600 picogram/milliliter (148-443 picomol/liter).
A deficiency often manifests itself first in the development of neurological dysfunction that is almost indistinguishable from senile dementia and Alzheimer's disease. There is little question that many patients exhibiting symptoms of Alzheimer's actually suffer from a vitamin B12 deficiency. Their symptoms are totally reversible through effective supplementation. A low level of vitamin B12 has also been associated with asthma, depression, AIDS, multiple sclerosis, tinnitus, diabetic neuropathy and low sperm counts. Clearly, it is very important to maintain adequate body stores of this crucial vitamin.
The amount of vitamin B12 actually needed by the body is very small, probably only about 2 micrograms or 2 millionth of a gram/day. Unfortunately, vitamin B12 is not absorbed very well so much larger amounts need to be supplied through the diet or supplementation. The richest dietary sources of vitamin B12 are liver, especially lamb's liver, and kidneys. Eggs, cheese and some species of fish also supply small amounts, but vegetables and fruits are very poor sources. Fortunately, oral supplementation with vitamin B12 is safe, efficient and inexpensive. Most multi-vitamin pills contain 100-200 microgram of the cyanocobalamin form of B-12. This must be converted to methylcobalamin or adenosylcobalamin before it can be used by the body. Some physicians still maintain that monthly injections of vitamin B12 is required to maintain adequate levels in the elderly and in patients with a diagnosed deficiency.

Where it is found
Vitamin B12 is found naturally in food sources (principally animal products) in protein-bound forms. Animal products are the principal food sources of vitamin B12. B12 cannot be made by plants or by animals. Cyanocobalamin is the principal form of vitamin B12 used in nutritional supplements and for fortification of foods. Methylcobalamin is also available for nutritional supplementation and hydroxocobalamin is available for parenteral administration. Good sources of vitamin B12 include liver, tuna, cottage cheese, yogurt and eggs. Most standard multivitamin supplements also provide the recommended daily allowance of vitamin B12. Food-form B12 is comprised of protein-bound methylcobalamin and adenosylcobalamin. The only reliable unfortified sources of vitamin B12 are meat, dairy products and eggs.

See Cobalamin related videos:
video icon What is Vitamin B12 Why does our body need B12(video module - 7.28 minutes)
video icon Vitamin B12 Deficiency - Video Tutorial #1 (video module - 8.24 minutes)
Product related PDF file
Cobalamin, folic acid, and homocysteine
Cobalamin- The Vitamin B12
Vitamin B Sources and Bioavailability

Benefits / uses
Pernicious Anemia
Pernicious anemia occurs when stomach cells are not able to make intrinsic factor, and the body cannot absorb vitamin B12. Symptoms include weakness, pale skin, diarrhea, weight loss, fever, numbness or tingling sensation in the hands and feet, loss of balance, confusion, memory loss, and moodiness. Vitamin B12 supplements in high doses, either given as injections or orally, are prescribed to treat pernicious anemia.

Heart Disease
Many studies indicate that patients with elevated levels of the amino acid homocysteine are roughly 1.7 times more likely to develop coronary artery disease and 2.5 times more likely to suffer from a stroke than those with normal levels. Homocysteine levels are strongly influenced by B complex vitamins, particularly vitamins B9, B6, and B12.

The American Heart Association recommends that, for most people, an adequate amount of these important B vitamins be obtained from diet, rather than taking extra supplements. Under certain circumstances, however, supplements may be necessary. Such circumstances include elevated homocysteine levels in someone who already has heart disease or who has a strong family history of heart disease that developed at a young age.

A vitamin B12 deficiency causes fatigue. One small study, done several years ago, suggested that some people who were not deficient in B12 might gain more energy from B12 injections. One preliminary study indicated that people with chronic fatigue syndrome might benefit from B12 injections.

Breast Cancer
Studies have shown that women who get more folate in their diet have lower incidence of breast cancer. Vitamin B12 works with folate in the body, so it may help contribute to a lesser risk. Another preliminary study suggested that postmenopausal women who had the lowest amounts of B12 in their diet had an increased risk for breast cancer.

Male Infertility
Studies suggest that vitamin B12 supplements may improve sperm counts and sperm mobility.

Vitamin B12 injections given by a doctor may help treat symptoms of chronic asthma.

Cognitive Impairment
Preliminary studies in people with Parkinson's Disease show that those who are cognitively impaired have much lower serum B12 levels than those who are not cognitively impaired.

When To Take/Types To Take
Vitamin B12 supplements are best taken with meal.
The commercial form of vitamin B12 is cyanocobalamin and
Methylcobalamin. These forms of B12 is available in a tablet (or capsule), as well as a lozenge.
The intestinal absorption of vitamin B12 is dependent upon its binding with the glycoprotein intrinsic factor. The exception to the dependency is if B12 is administered by injection, or absorbed sublingually (under the tongue). B-12 lozenges are used sublingually to promote better absorption. Some research supports the concept of better B12 absorption sublingually


arw Newborns - 6 months: 0.4 mcg (adequate intake)
arw Infants 6 months - 1 year: 0.5 mcg (adequate intake)
arw Children 1 - 3 years: 0.9 mcg (RDA)
arw Children 4 - 8 years: 1.2 mcg (RDA)
arw Children 9 - 13 years: 1.8 mcg (RDA)
arw Adolescents 14 - 18 years: 2.4 mcg (RDA)

arw 19 years and older: 2.4 mcg (RDA)*
arw Pregnant females: 2.6 mcg (RDA)
arw Breastfeeding females: 2.8 mcg (RDA)
Because 10 - 30% of older people may not absorb B12 from food very efficiently, it is recommended that those older than 50 years meet their daily requirement through a supplement containing B12.

Pos sible Side effects / Precautions / Possible Interactions:
Vitamin B12 is considered safe and non-toxic. Taking any one of the B complex vitamins by itself for a long period of time can result in an imbalance of other important B vitamins. For this reason, it is generally important to take a B complex vitamin with any single B vitamin. As noted earlier, taking folic acid at high doses can mask a vitamin B12 deficiency, so these vitamins are often taken together.

Possible Interaction:
If you are currently being treated with any of the following medications, you should not use vitamin B12 supplements without first talking to your health care provider.
Medications that reduce levels of B12 in the body include:
arw Anticonvulsants -- include phenytoin (Dilantin), phenobarbital, primidone (Mysoline)
arw Chemotherapy medications -- particularly methotrexate
arw Colchicine -- used to treat gout
arw Bile acid sequestrants -- used to lower cholesterol; include colestipol (Colestid), cholestyramine (Questran), and colsevelam (Welchol)
arw H2 blockers -- used to reduce stomach acid; include cimetidine (Tagamet), famotidine (Pepcid AC), ranitidine (Zantac)
arw Metformin (Glucophage) -- medication taken for diabetes
arw Proton pump inhibitors -- used to reduce stomach acid; include esomeprazole (Nexium), lansprazole (Prevacid), omeprazole (Prilosec), rabeprazole (Aciphex)

Antibiotics, Tetracycline:
Vitamin B12 should not be taken at the same time as tetracycline because it interferes with the absorption and effectiveness of this medication. Vitamin B12 should be taken at different times of the day from tetracycline. (All vitamin B complex supplements act in this way and should be taken at different times from tetracycline.)

Research studies / References

arw Abularrage CJ, Sidawy AN, White PW, Aidinian G, Dezee KJ, Weiswasser JM, Arora S. Effect of folic Acid and vitamins B6 and B12 on microcirculatory vasoreactivity in patients with hyperhomocysteinemia. Vasc Endovascular Surg. 2007 Aug-Sep;41(4):339-45.

arw Adachi S, Kawamoto T, Otsuka M, Todoroki T, Fukao K. Enteral vitamin B12 supplements reverse postgastrectomy B12 deficiency. Ann Surg. 2000;232(2):199-201.

arw Alpert JE, Mischoulon D, Nierenberg AA, Fava M. Nutrition and depression: focus on folate. Nutrition. 2000;16:544-581.

arw Bauman WA, Shaw S, Jayatilleke E, Spungen AM, Herbert V. Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin. Diabetes Care. 2000;13(9):1227-1231.

arw Booth GL, Wang EE. Preventive health care, 2000 update: screening and management of hyperhomocysteinemia for the prevention of coronary artery disease events. The Canadian Task Force on Preventive Health Care. CMAJ. 2000;163(1):21-29.

arw Bottiglieri T, Laundy M, Crellin R, Toone BK, Carney MW, Reynolds EH. Homocysteine, folate, methylation, and monoamine metabolism in depression. J Neurol Neurosurg Psychiatry. 2000;69(2):228-232.

arw Chatterjee S, Chowdhury RG, Khan B. Medical management of male infertility. J Indian Med Assoc. 2006 Feb;104(2):74, 76-7.

arw Cuskelly GJ, Mooney KM, Young IS. Folate and vitamin B12: friendly or enemy nutrients for the elderly. Proc Nutr Soc. 2007;66(4):548-58.

arw Kaptan K, Beyan C, Ural AU, et al. Helicobacter pylori -- is it a novel causative agent in vitamin B12 deficiency? Arch Intern Med. 2000;160(9):1349-1353.

arw Konings EJ; Committee on Food Nutrition. Water-soluble vitamins. JAOAC Int. 2006 Jan-Feb;89(1):285-8.

arw Kris-Etherton P, Eckel RH, Howard BV, St. Jeor S, Bazzarre TL. Lyon diet heart study. Benefits of a Mediterranean-style, National Cholesterol Education Program/American Heart Association Step I dietary pattern on cardiovascular disease. Circulation. 2001;103:1823-1825.

arw Louwman MW, van Dusseldorp M, van de Vijver FJ, et al. Signs of impaired cognitive function in adolescents with marginal cobalamin status. Am J Clin Nutr. 2000;72(3):762-769.

arw Moore D, Jefferson J. Handbook of Medical Psychiatry, 2nd ed. Philadelphia, PA: Elsevier Mosby. 2004;Chapter 234.

arw National Academy of Science. Recommended Daily Allowances. Accessed August 1, 2007.

arw Nutrients and Nutritional Agents. In: Kastrup EK, Hines Burnham T, Short RM, et al, eds. Drug Facts and Comparisons. St. Louis, Mo: Facts and Comparisons; 2000:4-5.

arw Ryan-Harshman M, Aldoori W. Vitamin B12 and health. Can Fam Physician. 2008;54(4):536-41.

arw Schnyder G. Decreased rate of coronary restinosis after lowering of plasma homocysteine levels. N Engl J Med. 2001;345(22):1593-1600.

arw Sinclair S. Male infertility: nutritional and environmental considerations. Alt Med Rev. 2000;5(1):28-38.

arw Snowdon DA, Tully CL, Smith CD, Riley KR, Markesbery WR. Serum folate and the severity of atrophy of the neocortex in Alzheimer disease: findings from the Nun Study. Am J Clin Nutr. 2000;71:993-998.

arw Triantafyllou NI, et al. Folate and vitamin B 12 levels in levodopa-treated Parkinson's disease patients: their relationship to clinical manifestations, mood and cognition. Parkinsonism Relat Disord. 2008;14(4):321-25.

arw Wang HX. Vitamin B12 and folate in relation to the development of Alzheimer's disease. Neurology. 2001;56:1188-1194.

arw Yoshihara K, Kubo C. Overview of medical treatment and management of chronic fatigue syndrome. Nippon Rinsho. 2007 Jun;65(6):1077-81. Review.