Joe Namath. Terry Bradshaw. Roger Staubach. Ken Stabler. These NFL superstars wore the number 12 and, depending on who you were rooting for, that number could be associated with some pretty bad cases of heartburn and stomachaches.

Ironically, you can lose your No. 12 - that's B-12, a vitamin essential for making healthy blood and nerve cells, DNA and preventing megaloblastic anemia - if you're taking a proton pump inhibitor to quell chronic heartburn or an H2RA (histamine 2 receptor antagonist) to treat a peptic ulcer.

And if you take either of those meds plus the oral diabetes medication metformin, look out: 10 percent to 30 percent of folks on metformin alone become B-12 deficient!

This new health alert is the result of a recent study that found taking PPIs and H2RAs for two or more years can cause a serious B-12 deficiency, which can lead to irreversible brain damage. This happens in part because B-12 bound in food is released by hydrochloric acid and gastric protease, which are suppressed by those meds.

The good news? A blood test can ID a deficiency. If you're taking PPIs or H2RAs, ask your doc to check. If you're deficient, you'll take a daily B-12 supplement and maybe get a booster shot. And you can help reverse the deficiency (the recommended daily allowance is 2.4 mcg for anyone 14 or older) by eating fish or skinless poultry (turkey has 48 mcg per serving). We don't recommend some shellfish, especially clams (even though they have 84 mcg per serving), because of other concerns, but that's another column.