Vitamin B12 is an essential water soluble vitamin that is commonly found in a variety of foods such as fish, shellfish, meats, and dairy products. It helps maintain healthy nerve cells and red blood cells, and is also needed to make DNA.

Vitamin B12 is bound to the protein in food. Hydrochloric acid in the stomach releases B12 from protein during digestion. Studies have shown that a deficiency of vitamin B12 can lead to ataxia (shaky movements and unsteady gait), muscle weakness, spasticity, incontinence, hypotension, vision problems, dementia, psychoses, and mood disturbances.

People at risk for vitamin B12 deficiency include strict vegetarians, elderly people, and people with increased vitamin B12 requirements associated with pregnancy, thyrotoxicosis, hemolytic anemia, hemorrhage, malignancy, liver or kidney disease.

Vitamin B12 deficiency is a cause of megaloblastic anemia. In this type of anemia, red blood cells are larger than normal, and the ratio of nucleus size to cell cytoplasm is increased.

There is evidence that intramuscular injections of 5mg of vitamin B12 given twice per week might improve the general well being and happiness of patients complaining of tiredness or fatigue.

Vitamin B12 Injections is important for metabolism. Metabolism within the body includes the processes of energy generation and use -- including nutrition, digestion, absorption, elimination, respiration, circulation, and temperature regulation. Studies indicate that absorption of Vitamin B12 decreases with an increase in age. Hence, an increased intake of B12 Injections is extremely useful for adults above fifty.