
The acidification of the blood and other body fluids. This condition can be due to acid accumulation or to the loss of bicarbonate buffering capacity from kidney disease. The pH of blood is tightly regulated; the normal range is between pH 7.3 and 7.4. A drop in blood pH below pH 7.3, which corresponds to increased hydrogen ion concentration, could signal excessive acidity of the blood (ACIDEMIA). Homeostatic mechanisms (the body’s regulatory system of checks and balances) help prevent acidosis. Bicarbonate and serum proteins take up hydrogen ions to neutralize excessive acid rapidly, while the kidneys more slowly compensate for acid production by excreting surplus hydrogen ions. Prolonged acidosis requires medical attention because it slows down many vital functions, including nerve transmission and heart muscle contraction. Symptoms of acidosis include nausea, vomiting, DIARRHEA, headache, rapid breathing, and, eventually, convulsions.
Two forms of acidosis are recognized: metabolic and respiratory. Metabolic acidosis can occur when metabolic acids accumulate excessively. For example, when the body burns FAT at a high rate, the liver converts FATTY ACIDS to KETONE BODIES, acidic substances. This condition may occur during crash DIETING and FASTING or in a person suffering from uncontrolled DIABETES MELLITUS or chronic ALCOHOLISM.
Excessive ingestion of acids, such as in aspirin poisoning, also causes acidosis. Metabolic acidosis can also result from vomiting or diarrhea, which cause excessive loss of ELECTROLYTES like BICARBONATE and upset the acid/base balance.
Renal disease may prevent the kidneys from adequately correcting acid production.
Respiratory acidosis can occur when breathing does not adequately remove carbon dioxide. Shallow breathing, associated with respiratory disease, can cause excessive CARBON DIOXIDE in the lungs, in turn causing carbon dioxide blood levels to rise and upset the bicarbonate buffer system of the blood.

A condition characterized by a burning pain near the stomach. Typically, this occurs an hour or so after a heavy (fatty) meal and is often relieved by taking ANTACIDS or by drinking MILK. Acid indigestion is the most common gastrointestinal complaint in the United States; one in 10 Americans suffer daily attacks. The pain associated with acid indigestion is caused by STOMACH ACID backing up into the ESOPHAGUS, the region of the throat connecting the mouth with the stomach. Acid indigestion can be caused by air gulped when swallowing large bites of food, which can keep the passageway open. Some food allergies and food sensitivities may trigger acid indigestion by relaxing the sphincter muscles that normally seal off the stomach juices from the esophagus after eating. Although the stomach lining is protected from acid by mucus, the unprotected esophagus is irritated by repeated exposure to acid.