Why Do I Need Monthly B-12 Shots?

The vitamin B-12 plays a role in DNA formation, nerve function, and red blood cell formation. This vitamin is found in food and supplements but has to be absorbed into the bloodstream through the stomach or intestines. People with specific conditions may find it difficult to absorb B-12 normally and may develop a deficiency. Monthly B-12 shots can be used to supply the vitamin for these patients. Understanding the medical conditions that may require monthly shots is key to making sure that you are appropriately using the medication.

To Treat Pernicious Anemia

One condition that may require monthly B-12 shots is pernicious anemia. In this condition, the parietal cells in the stomach are slowly destroyed, which leads to a deficiency in intrinsic factor, as noted by the Office of Dietary Supplements. The lack of intrinsic factor leads to an inability to absorb B-12; the B-12 deficiency can lead to health issues like megaloblastic anemia and neurological problems. Pernicious anemia occurs more commonly in people over the age of 60, according to The Linus Pauling Institute Micronutrient Information Center. Since the stomach has been damaged, you will not get enough B-12 -- even if you eat plenty of B-12-containing foods. People with pernicious anemia require monthly injections of the vitamin for life since the injections do not require absorption through the stomach.

After Surgical Removal of the Stomach or Intestines

Surgical removal of the stomach or part of the intestines can lead to B-12 deficiency, as well. If you have had gastric bypass surgery or other bariatric surgery, you will need to have B-12 injections monthly because your stomach will not be available to absorb the vitamin, as noted on Better Medicine. People who have had surgery for stomach cancer may also need to have these injections.

If You Have Severe Crohn's Disease

Inflammatory bowel diseases like Crohn's disease can cause significant scarring and damage to the intestines, which influences the organ's ability to absorb B-12. You may be able to absorb B-12 but not enough to maintain all of the bodily functions that require the vitamin, according to the Office of Dietary Supplements. Monthly injections may be required for these patients to supply B-12.

If You Have Celiac Disease

In celiac disease, the lining of the small intestine gets damaged and is unable to absorb necessary nutrients, as noted on PubMed Health. The damage comes from a reaction to gluten, which is found in wheat, barley, and rye. In an April 2002 study in the "European Journal of Gastroenterology and Hepatology," W. Dickey found that 12 percent of the study participants with celiac disease had B-12 deficiencies. If you have celiac disease, you may need monthly B-12 injections.

Considerations

Other conditions may lead to B-12 deficiency, as well. However, these conditions may not require monthly B-12 shots. Strict vegetarians who consume no animal products may develop a B-12 problem, but since the stomach and intestine are intact, B-12 supplements can be used, as noted by The Linus Pauling Institute Micronutrient Information Center. If you have taken acid-reducing medications for your stomach, you may also have problems absorbing B-12, according to Better Medicine; however, stopping the medication often corrects the problem. Monthly B-12 shots are only required for people who have long-term and irreversible changes in their stomach or intestines that interfere with absorption of the vitamin.