People who have chronic heartburn can find themselves living on antacids just to stay reasonably comfortable. Whether the heartburn is caused by gastroesophageal reflux disease (GERD) or something else, we already knew that these drugs had a big downside—they can interfere with digestion, encouraging diarrhea and gassiness and even promoting food sensitivities. But it just got worse for folks who rely heavily on antacids like omeprazole (Prilosec), esomeprazole (Nexium), lansoprazole (Prevacid), and famotidine (Pepcid). A large new study shows specifically that these drugs rob the body of a very important nutrient—vitamin B-12—which is essential for proper functioning of your nerves and your body’s ability to make blood cells and DNA.

Here’s the scoop: Because small studies had been cropping up hinting that antacid use might have something to do with why some people have a vitamin B-12 deficiency, a team of researchers from Kaiser Permanente, a major health-care organization, went ahead and accessed 14 years of medical and pharmacy records (1997 to 2011) of the company’s millions of members to look more closely for a link between antacid use and lack of vitamin B-12.

They found about 26,000 members who had been given a diagnosis of B-12 deficiency or had otherwise been prescribed a vitamin B-12 supplement. Then the team dug deep into those people’s medical and pharmacy records. The team was looking to see whether prescription antacid use was common in members with B-12 deficiency. To prevent any faulty assumptions, the researchers compared each member in this group with up to 10 matched controls—that is, members in the database who didn’t have B-12 deficiency but shared other key characteristics with the members who did. They also adjusted their findings to make sure that the B-12 deficiencies weren’t being caused by diabetes, thyroid disorders, smoking, alcohol abuse or other factors known to cause B-12 deficiency.

A wide variety of antacids were included in the study. You’re probably familiar with their commercial names—Prilosec, Nexium and Prevacid, which are proton pump inhibitors (PPIs)…and Pepcid and ranitidine (Zantac), which are histamine 2 receptor antagonists (H2RAs). PPIs, which are the most effective and popular, work by blocking the enzymes that make stomach acid. H2RAs stop overproduction of acid in a more roundabout way by blocking stomach cells that produce histamine.


The results of the study were striking. Essentially, if you’ve been taking one of those just-mentioned PPIs daily for two years or more, there’s a very good chance that you are not getting as much vitamin B-12 as your body needs. No wonder you’re feeling tired, foggy or light-headed, have muscle weakness, the runs or constipation, or feel like your heart or lungs are working too hard. Although only a medical exam can confirm why you feel this way, these are symptoms of vitamin B-12 deficiency.

Although B-12 deficiency was more frequently associated with use of PPIs than with use of H2RAs, both types of antacids were implicated…

• People in the study taking PPIs daily for two or more years were 65% more likely to be vitamin B-12 deficient than those not taking antacids daily…people on daily H2RAs were 25% more likely to be B-12 deficient than those not taking antacids daily.

• The higher the daily dose of a PPI, the higher the likelihood that the person was vitamin B-12 deficient after being on the PPI for two or more years. In fact, the highest average dosage (more than 1.5 pills each day) was associated with a whopping 95% increased risk for vitamin B-12 deficiency. The lowest dosage of a PPI was associated with a 63% increased risk—still very high. In comparison, the highest dosage of H2RAs was associated with a 37% increased risk for vitamin-B deficiency.

• The younger a person was, the more vulnerable he or she was to vitamin B-12 deficiency. This was true if he or she was taking a PPI or a PPI plus an H2RA but not an H2RA alone. For example, B-12 deficiency was eight times more likely to be diagnosed in PPI users who were age 29 or younger than in those age 80 or older. Why is a topic for further investigation.

• Women were at higher risk than men for B-12 deficiency. Among all people studied who had been taking PPIs or PPIs and H2RAs but not H2RAs alone for two years or more, women had an 84% higher risk of being vitamin B-12 deficient than people not taking antacids…while men had a 43% higher risk.

Why is this happening? The researchers didn’t get into causality, but stomach acid is the very thing that makes your body separate out vitamins B-12 from proteins in the foods you eat, and this separation is what allows your body to absorb B-12 from your gut.

In other words, the antacids are out-and-out preventing you from digesting an incredibly important nutrient.


Fortunately, when people stop using antacids, the body’s ability to break out and absorb vitamin B-12 returns to normal—but not very quickly. Although the incidence of vitamin B-12 deficiency for current antacid users and people who had gone antacid-free for about a year was about the same, the incidence was halved for former daily antacid users who had been antacid-free for at least two years.

What you can do: If you must take an antacid on a regular basis, take the lowest dose that will effectively relieve your symptoms. This may help reduce your risk of vitamin B-12 deficiency. But don’t make this decision alone. Talk to your doctor. If you’re using a PPI, discuss possibly switching to an H2RA or using a lower dose of the PPI. You also may consider taking a B-12 supplement. If a blood test confirms that you are vitamin B-12 deficient, though, your doctor may give you a special, high-dose prescription or even suggest that you get vitamin B-12 injections, depending on how B-12–deficient you are.

But your real goal is to get at the root cause of your heartburn and do away with the need for any regular antacid use. For lots of information on how to do this, see the articles in the box above.