Heartburn drugs linked to vitamin deficiency

Knocking down stomach acid may come with a cost. People with a deficiency in vitamin B12 are more likely to regularly use popular heartburn drugs than those who aren’t deficient, researchers find. The connection suggests that the drugs interfere with the digestive process that extracts the vitamin from foods.

Researchers analyzing a large database of medical records report in the Dec. 11 JAMA that taking proton pump inhibitors, or PPIs, was associated with a two-thirds increase in the risk of vitamin B12 deficiency. A chronic B12 shortage can lead to anemia, nerve damage and dementia.

PPIs, sold as Nexium, Prilosec and other brands, curb the stomach’s production of acid. This reduces reflux, in which stomach acid splashes up into the tender esophagus and causes heartburn.

But stomach acid is needed for digestion, part of which involves carving vitamin B12 out of proteins in foods. By changing the pH of the stomach, PPIs might inhibit how much vitamin B12 gets cleaved from proteins, says Robert Valuck, a pharmacist at the University of Colorado Denver’s campus in Aurora, who wasn’t part of the new study.

Douglas Corley, a gastroenterologist at the Kaiser Permanente Division of Research in Oakland, Calif., and his colleagues identified nearly 26,000 people with vitamin B12 deficiency in the Kaiser records and matched them up with roughly 184,000 people who didn’t have the shortage. The researchers found that 16.2 percent of the deficient group took a PPI or another heartburn drug for at least two years, compared with 10.4 percent of the people with normal levels of vitamin B12. The scientists linked PPIs with a risk of vitamin B12 deficiency 65 percent higher than that of not taking any heartburn drug. The apparent risk lingered for three years after stopping PPIs, decreasing gradually.

People taking less potent heartburn medications belonging to a family of drugs that includes Zantac had a risk of vitamin B12 deficiency that was 25 percent greater than did those not taking heartburn drugs.

Still, about four-fifths of the people who had low levels of vitamin B12 weren’t taking any of the acid-blockers. That suggests that other factors contribute to B12 deficiency, Valuck says, such as nutrition, age, genetics, exercise levels and alcohol consumption. The good news, he says, is that this deficiency, whatever the cause, “is fairly easy to remedy. It’s cheap and easy to take in a multivitamin.”  

A simple blood test reveals low vitamin B12 levels. The exact prevalence of vitamin B12 deficiency in the population is unknown, but studies suggest it ranges from 5 to 20 percent, with highest rates in the elderly. Corley says the new results raise questions about whether people taking PPIs should get their vitamin levels checked. He also wonders whether those on high PPI doses might manage with lower amounts, since higher doses were linked to greater risk of vitamin B12 deficiency.