B-12 shots are given to prevent or correct a deficiency of vitamin B-12, reports Mayo Clinic. These shots are also given to people with a condition called pernicious anemia. Pernicious anemia is a decrease in red blood cells caused by an inability to absorb vitamin B-12 properly, states MedlinePlus.Continue Reading
A B-12 injection delivers a dose of vitamin B-12 directly into the bloodstream, according to MedlinePlus. This makes it useful for treating B-12 deficiency in people whose intestines do not absorb B-12 properly. The normal dosage for B-12 injections varies, but it is common to receive a daily shot for approximately the first week of treatment. After the deficiency has been corrected, monthly injections may be needed to maintain normal B-12 levels.
The human body needs vitamin B-12 to produce red blood cells and DNA, reports WebMD. Because vitamin B-12 is found in meats and dairy products, vegans may not get enough of it in their diets. Vitamin B-12 deficiency also has several medical causes. Crohn's disease, intestinal parasites, atrophic gastritis and celiac disease all affect the absorption of nutrients in the digestive tract. Atrophic gastritis is a condition characterized by thinning of the stomach lining. Other causes of B-12 deficiency include lupus, Graves' disease, heavy drinking, and surgery to remove all or part of the intestine.Learn more about Medications & Vitamins