Ulcers

Until recently, excess stomach acid was believed to be the cause of ulcers. Hydrochloric acid (HCL) is normally produced in the stomach to help break down food. HCL is secreted from special cells in the stomach lining, is mixed with the stomach contents, and initiates the preliminary digestion of proteins in the stomach. From the stomach, the partially digested food moves into the duodenum, where more digestion takes place. But before the partially broken down food moves from the stomach to duodenum, the acid must be neutralized. If it is not, the acidic food will irritate the sensitive duodenum. Sodium bicarbonate—the active ingredient in baking soda—is released from other cells in the stomach lining and neutralizes the acid in the partially digested food before it moves into the duodenum.

Sometimes, however, the acid is not neutralized effectively, and the duodenum is irritated by the acidic food. In this case, a duodenal ulcer may develop. Sometimes the lining of the stomach itself cannot tolerate the high levels of acid that are released within the stomach. In this case, a gastric ulcer lining may result. In either of these cases, the ulcers can be traced to a sensitivity to acid or to its overproduction.

But acid overproduction or sensitivity are not the only causes of ulcers. A bacterium called Heliobacter pylori, discovered and named in 1982, has been shown to cause ulcers by colonizing the lining of the stomach. These bacteria can survive in the stomach's highly acidic environment because they have an enzyme that neutralizes acid. Scientists now believe that most—60%—of all ulcers diagnosed throughout the world can be traced to the H. pylori bacterium.