Vitamin B12, also called cobalamin, is one of eight B vitamins. In general, all B vitamins help the body convert food (carbohydrates) into fuel (glucose), which is used to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body use fats and protein. B complex vitamins are needed 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 helps in the production of DNA and RNA, the body's genetic material. Vitamin B12 works closely with vitamin B9, also called folate or folic acid, to help make red blood cells and to help iron work 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. However, researchers are not sure whether homocysteine is a cause of heart disease or just a marker that indicates someone may have heart disease.

Low levels of B12 can cause a range of symptoms including:

• Fatigue
• Shortness of breath
• Diarrhea
• Nervousness
• Numbness
• Tingling sensation in the fingers and toes

Severe deficiency of B12 causes nerve damage.

Others at risk for B12 deficiency include:

• Vegans and vegetarians who do not eat dairy or eggs, since vitamin B12 is found only in animal products
• People with problems absorbing nutrients due to Crohn disease, pancreatic disease, weight loss surgery, or medications
• 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
• People with an eating disorder
• People with HIV
• People with diabetes
• Elderly people

Folic acid (vitamin B9), especially when taken in high doses, can mask the symptoms of a vitamin B12 deficiency. The danger is that without symptoms, someone with a vitamin B12 deficiency may not know it, and could run the risk of developing nerve damage.

Each dose contains 2.5 mg. Patients may take up to 5 mg.

Maximum Doses: 2