Vitamin B-12 is a water-soluble vitamin naturally present in proteins such as meat, poultry, fish and, to a lesser extent, milk. It is vital for the healthy development and function of the brain, nerves, blood cells and other parts of the body. Proton pump inhibitors, used ubiquitously in the U.S. for gastroesophageal reflux disease, peptic ulcers and even heartburn reduce the production of gastric acid in the stomach, which is necessary for the absorption of food-bound vitamin B-12 by the body.
Vitamin B-12 Absorption
Acidity and enzymes in the stomach are required to release vitamin B-12 from the protein it is bound to in animal-based foods. After this release, B-12 combines with intrinsic factor released from the stomach's parietal cells, and this facilitates absorption of B-12 through the intestinal wall into the bloodstream. Unlike B-12 found in meat, fish and dairy products, vitamin B-12 that is added to fortified foods such as cereals or that is found in dietary supplements is already in its free form and does not require stomach acid for absorption. A typical Western diet provides much more than the recommended daily allowance of B-12 and your body usually maintains a large B-12 reserve that can last two to five years even in the presence of severe malabsorption. One group that is at risk for B-12 deficiency, however, is the elderly population, 10 to 30 percent of whom may already have a condition called atrophic gastritis, according to the Linus Pauling Institute of Oregon State University. Atrophic gastritis is a chronic inflammation of the stomach lining that results in reduced stomach acid production.
Evidence
Among the dozen or so studies that have examined the effect of proton pump inhibitors on vitamin B-12 absorption, the results have been inconsistent regarding to what extent proton pump inhibitors interfere with the absorption of protein-based vitamin B-12 and cause decreased vitamin B-12 blood levels. Several studies, including one by Marcuard published in 1994 in the "Annals of Internal Medicine," have shown that short-term use of proton-pump inhibitors can reduce the absorption of protein-bound vitamin B-12 to a minimal extent. In contrast, a handful of studies of long-term use of proton pump inhibitors in nonelderly patients did not demonstrate any reduction in vitamin B-12 blood levels, according to a 2010 review of proton pump safety in the "World Journal of Gastroenterology." Long-term use of proton pump inhibitors among individuals over 60 years of age has decreased B-12 levels in some studies, including one by T.S. Dharmarajan that followed 659 patients and was published in 2008 in "JAMDA," but not in others.
Populations at Risk
Based on what is known about how the body handles vitamin B-12 and the populations most at risk for B-12 deficiency, it is unlikely that short-term use of proton-pump inhibitors will result in a deficiency of vitamin B-12, especially if dietary intake is adequate. Situations in which use of proton pump inhibitors may present a higher risk of vitamin B-12 deficiency include long-term use of two years or more; chronic use in the elderly; chronic use in individuals with poor dietary intake of vitamin B-12, such as those who follow a strict vegetarian diet; and use in high doses that render a patient achlorhydric, or devoid of stomach acid, as is sometimes required in the treatment of a condition called Zollinger-Ellison syndrome.
Recommendations
In circumstances where use of a proton pump inhibitor may increase the risk for vitamin B-12 deficiency, the Institute of Medicine Food and Nutrition Board and the Linus Pauling Institute recommend vitamin B-12 in the form of a supplement or in B-12-fortified foods such as cereals because gastric acid is not required for its absorption in these forms. The National Institute of Health's Office of Dietary Supplements and several investigators recommend screening patients on long-term proton-pump inhibitors for vitamin B-12 deficiency and supplementing accordingly.
Symptoms
Because the body stores a large amount of B-12, symptoms of vitamin B-12 deficiency may take several years to appear. Megaloblastic anemia, or a lack of mature, normal-size red blood cells is one of the most serious complications of B-12 deficiency and is associated with fatigue, shortness of breath, weakness and confusion. Neurologic complications of vitamin B-12 deficiency can result in persistent tingling, or numbness in your hands and feet, and other problems, such as confusion, forgetfulness, irritability or other personality changes. These symptoms can occur before vitamin B-12 deficiency anemia occurs, and can occur without anemia in about 25 percent, according to the Institute of Medicine Food and Nutrition Board. Without treatment for B-12 deficiency, neurologic complications can become permanent.
References
- Linus Pauling Institute; Vitamin B12; Jane Higdon; March 2003
- "Alimentary Pharmacology and Therapeutics"; Long-term Use of Proton Pump Inhibitors and Vitamin B12 Status in Elderly Individuals; WPJ den Elzen et al.; March 15, 2008
- NIH Office of Dietary Supplements; Vitamin B12; May 2010
- "American Family Physician"; Vitamin B12 deficiency; Robert C. Oh et al.; March 1, 2003
- "World Journal of Gastroenterology"; Safety of the Long-Term Use of Proton Pump Inhibitors; Alan BR Thomson et al.; May 21, 2010
- "Journal of the American Medical Directors Association"; Do Acid-Lowering Agents Affect Vitamin B12 Status in Older Adults? TS Dharmarajan et al.; March 2008
