If you watch television commercials, you may have the impression that stomach acid is one of your stomach's worst enemies, but nothing could be farther from the truth. Despite what the numerous ads for decreasing stomach acid suggest, stomach acid plays an essential role in food digestion and in keeping intestinal infections at bay.
Type
The main acid found in the stomach is hydrochloric acid, produced by the parietal cells in the stomach. A thick layer of mucus protects the stomach from the acid that would normally digest it. The gastric juices in the stomach normally maintain an acidic pH of less than 3.5. Gastrin, a hormone, controls the release of stomach acid from the parietal cells.
Purpose
For the food you eat to be absorbed into the cells and used for energy, it must first be broken down into absorbable substances. It's hard to look at a piece of steak, for instance, and imagine how it gets into your bloodstream. Digestion starts in the mouth, when you initiate the food breakdown process by chewing. As food enters the stomach, acidic digestive juices carry on the breakdown process. The stomach churns at the same time, mashing the food into even smaller pieces. Stomach acid also performs the valuable function of killing most microbes on contact, decreasing your risk of getting sick from pathogens in food.
Excess Production
Excess stomach acid production can cause inflammation of the lining of the stomach, called gastritis. Stomach ulcers or ulcers in the small intestine are most often caused by bacteria called Helicobacter pylori, but excessive stomach acid can also contribute to ulcer formation by burning the stomach lining. Excessive acid production can also worsen gastroesophageal reflux, which produces heartburn when stomach acid regurgitates through the esophageal sphincter into the esophagus, which does not have an acid-resistant lining like the stomach does.
Too Little Production
While you may think of acid indigestion as a problem of too much acid production, too little acid can also cause problems. Low levels of stomach acid, called hypochlorydia, and complete lack of stomach acid, called achlorhydria, can both cause can increased risk of intestinal infections, since stomach acid kills germs. Stomach acid also helps break down foods so that vitamins and minerals can be easily absorbed. Low stomach acid levels may result in vitamin or mineral deficiencies such as low levels of zinc, calcium or B-12. Long-term overuse of antacids can cause achlorhydria or hypochlorydia. As you age, you have an increased risk of developing low acid levels.
References
- Colorado State University; The Parietal Cell: Mechanism of Acid Secretion; R. Bowen; March 2010
- MD Guidelines: Achlorhydria and Hypochlorhydria
- FamilyDoctor.org; Ulcers: What You Can Do to Heal Your Ulcer; January 2011
- National Institute of Diabetes and Digestive and Kidney Disorders; Your Digestive System and How It Works; April 2008
- NYU Langone Medical Center; Heartburn; D. Wood, R.N.; September 2010
