The stomach produces stomach acid at the thought, smell, taste and presence of food. The release of stomach acid is the first step in a chain of events that break down food. However, stomach acid is involved in more than just digestion. It also helps protect the body from infections and assists with the assimilation and absorption of critical nutrients needed to make red blood cells and strong bones.
Protein digestion begins in the stomach. Stomach acid contains an enzyme called pepsin that helps break down large protein molecules into simpler compounds. Stomach acid also stimulates the pancreas to produce additional enzymes to further the process of protein digestion. The final end-products of protein break down are amino acids, which are necessary for many critical functions in the body such as the production of neurotransmitters and thyroid hormones.
Stomach acid is also required to release vitamin B-12 from food. Vitamin B-12 is essential for proper red blood cell formation, neurological function and DNA synthesis. With aging, stomach acid production slows down and the body becomes increasingly vitamin B-12 deficient. According to Harvard School of Public Health, an estimated 10 to 30 percent of adults over the age of 50 have difficulty absorbing vitamin B-12 from food due to low stomach acid.
The pH of stomach acid generally ranges between 1.5 and 3.5. The potent stomach acid creates a hostile environment for bacteria, parasites and other microorganisms such that it protects your body from the invasion of harmful microbes. According a study published in the February 2008 issue of "Infection and Immunity," mice that were hypochlorhydric -- a term for low or absent stomach acid -- experienced an increased susceptibility to bacteria such as Salmonella. Furthermore, the bacteria responsible for the infections were found in greater amounts in the hypochlorhydric mice compared to mice that had normal stomach acid.
An article published in the February 2010 issue of "Scandinavian Journal of Gastroenterology" stated that stomach acid is needed in order to effectively dissolve and absorb calcium. In addition, the article suggested that suppressing stomach acid with acid-blocking medications may increase the risk of osteoporosis. An earlier study published in the August 2008 issue of the "Canadian Medical Association Journal" supported these findings as well; it showed the use of a class of acid-blocking drugs known as proton pump inhibitors for more than five years increases the risk of fractures. The fact that people produce less stomach acid as they age may explain why older people are at risk for osteoporosis and fractures.
- Mary Baldwin College: Chapter 17: The Digestive System
- Christiane Northup, M.D. Thyroid Disease: What You Need to Know
- Harvard School of Public Heath: Vitamin B12 Deficiency: Causes and Symptoms
- National Institutes of Health Office of Dietary Supplements: Vitamin B12
- Infection and Immunity: Influence of Gastric Acid on Susceptibility to Infection with Ingested Bacterial Pathogens
- Scandinavian Journal of Gastroenterology: Hypochlorhydric Stomach: A Risk Condition for Calcium Malabsorption and Osteoporosis?
- Canadian Medical Association Journal: Use of Proton Pump Inhibitors and Risk of Osteoporosis-Related Fractures
- The Encyclopedia of Nutrition and Good Health; Robert A. Ronzzio, Ph.D.
- MedlinePlus: Stomach Acid Test
- Medical Physiology: Principles for Clinical Medicine; Rodney A. Rhoades, Ph.D. and David R. Bell
- Pixland/Pixland/Getty Images