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.

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.
Fatigue

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.

Asthma
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

Doses
Pediatric