The Relation Between IBS and a Vitamin B12 Deficiency

IBS, or irritable bowel syndrome, and vitamin B-12 deficiency are medical conditions that can cause similar symptoms. Because of this, one condition can be prematurely misdiagnosed as the other. Diagnostic tests can determine if your symptoms are a result of an insufficient amount of vitamin B-12. Despite the similarities in their symptoms, more research is needed to establish a link between lack of vitamin B-12 to the development of IBS. Talk to your doctor about further tests and possible treatments if you believe you may be suffering from either condition.

A woman is laying in bed holding her stomach.
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IBS and vitamin B-12 can both cause frequent and uncontrollable diarrhea. A chronic lack of vitamin B-12 can result in the development of pernicious anemia, also known as vitamin deficiency anemia, which causes fever, irritability, dizziness, difficulty breathing, weakness, fatigue, weight loss, paleness and tingling in the feet and hands that indicates nerve damage. IBS is characterized by either frequent diarrhea, abdominal pain and gas or constipation and bloating.


A lack of sufficient vitamin B-12 affects the digestive system because the vitamin is essential in the metabolism of carbohydrates, fats and protein. People who have the highest risk of developing a vitamin B-12 deficiency include vegans, people with HIV or those who have a severely compromised immune system, people suffering from digestive system disorders like a parasitic infection or pancreatic disease and people infected with Helicobacter pylori, a bacteria that inhibits the body's ability to produce the compound needed for proper vitamin B-12 absorption. Unlike vitamin B-12 deficiency, IBS is generally not associated with malabsorption, and the two are generally not associated with one another. The exact cause of IBS is unknown, though PubMed Health reports that IBS may be caused by an intestinal muscle disorder or infection and can be worsened by stress and certain foods. Research does not indicate that IBS is connected to a deficiency of vitamin B-12.


There are no available tests that can give a definite diagnosis of IBS, though a colonoscopy, CT scan or flexible sigmoidoscopy can help reveal whether there are underlying intestinal problems. Vitamin B-12 deficiency can be ruled out as a possible cause of IBS-like symptoms with a CBC, or Complete Blood Count test. Since adequate amounts of vitamin B-12 are needed for proper blood cell production, a blood test that reveals abnormal red blood cells or a lower than normal amount of hemoglobin, white blood cells or platelets can indicate a vitamin B-12 deficiency.


According to the University of Maryland Medical Center, a vitamin B-12 deficiency can, in most cases, be easily remedied by consuming dairy products, beef, fish, pork, or eggs on a regular basis. Vegans or elderly people whose digestive systems are not working optimally are recommended to take a daily supplement containing 2.4 mcg of vitamin B-12 daily. Speak to your doctor before using any vitamin B-12 supplement since dietary supplements are not regulated by the Food and Drug Administration for effectiveness, purity or safety and because vitamin B-12 supplementation may interfere with drugs like glucophage, anticonvulsants, methotrexate, H2 blockers and bile-acid medications used to lower cholesterol. Unfortunately, there is no cure for IBS, although dietary changes, fiber supplements like psyllium and medications that relax the intestines, prevent diarrhea and inhibit digestive system muscle spasms may help. No research indicates that indicates vitamin B-12 supplementation can treat or decrease the severity of IBS.

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