Bacteria, not stomach acid or stress, cause peptic ulcers

Dear Doctor K: I’ve been diagnosed with a peptic ulcer. What does that mean? And what’s the treatment?

Answer: A peptic ulcer is a sore or hole that forms in the lining of the stomach or upper part of the small intestine (called the duodenum). If your ulcer is small, you may have few symptoms. If the ulcer is deep, it can cause bleeding or serious pain.

What causes the ulcer? For many decades, doctors thought they knew the answer: It was acid. Stress and psychological problems led a person to make too much stomach acid.

It was a reasonable theory. Your stomach does make acid to help you digest food. The acid also could digest your stomach if it weren’t protected. But it is: Your stomach is lined with a layer of special cells and mucus. The mucus protects the lining of the stomach and duodenum from damage by acid and digestive enzymes.

The “acid theory” held that peptic ulcers were caused either by too much stomach acid, or by a failure in the production of protective mucus, or both. Almost everyone was convinced the acid theory was correct, even though there was little evidence for it.

Beginning in the early 1980s, two young Australian doctors — Barry Marshall and Robin Warren — pursued a very different theory. They found an unusual kind of bacteria, Helicobacter pylori, inside many peptic ulcers. They argued that these bacteria cause inflammation, weakening the stomach lining and the protective mucus. When stomach acid got into the ulcer, it made the ulcer worse. (I’ve put an illustration of this on my website, AskDoctorK.com.) To help prove the point, Marshall swallowed the bacteria — and shortly thereafter developed peptic ulcers.

For a decade their ideas were ridiculed. But slowly the evidence became undeniable. The bacteria were even identified as a cause of stomach cancer. In 2005, Marshall and Warren were honored with the Nobel Prize — and very few of their colleagues who had ridiculed them apologized.

Another common cause of stomach lining irritation and ulcers is nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen (Advil, Motrin) and naproxen (Aleve, Naprosyn). NSAIDs block the formation of certain chemicals that normally help protect against ulcers.

Contrary to popular belief, stress and spicy foods do not seem to increase the risk of ulcers.

Treatment of ulcers depends on their cause. Ulcers caused by H. pylori are treated with antibiotics and acid-suppressing medication. Successfully killing the H. pylori bacteria will greatly reduce your chances of developing another ulcer.

If your ulcer was caused by an NSAID, the treatment is to stop taking it. Your ulcer will begin to heal almost immediately. You’ll also take medications to reduce acid damage during healing. These may include antacids to neutralize stomach acids. Or you may take H2 blockers or proton pump inhibitors to decrease the amount of acid your stomach produces. Acid makes any ulcer worse, but as Marshall and Warren showed, the acid is not the cause of peptic ulcers.