In order to function properly, the body has to be able to keep the levels of certain chemicals and compounds in the body at a near steady-state. This is known as homeostasis and it is a critical part of all living organisms. As a result, your body needs to keep certain fluids, such as the blood, slightly alkaline.
Acidity and Health
The chemical environment of the body affects the way that many different cells and proteins work. For example, the stomach needs to be acidic in order for digestive proteins to properly function. If a compartment in the body becomes too acidic or too alkaline, proteins can change their shape, the Food Science department at Ohio State University notes, which can cause them to be unable to function.
Blood and pH
The balance of acids and bases in fluids can be measured using the pH scale, which defines neutrality as 7. Acids have a low pH and basic or alkaline substances have a high pH. The pH of the blood is tightly regulated because it has access to every tissue in the body; as a result, the pH of the blood is kept between 7.35 and 7.45, which makes it slightly alkaline. Other fluids in the body, such as saliva and urine, also have normal pH ranges, but these are more variable because changes in their pH will not have as dramatic on the body as a whole.
Because the alkalinity of the blood is so critical, the human body has three ways of regulating blood pH. Carbon dioxide, which is a byproduct of the way cells use glucose, is mildly acidic; its levels can be controlled by changes in your breathing rate. The kidneys also can excrete excess acid via the urine. Finally, the blood is filled with special chemical mixes known as buffers, which work by resisting any sudden changes in pH.
If the pH of the blood gets too low, acidosis is the result. Acidosis can be caused by problems with breathing, resulting in respiratory acidosis. Metabolic acidosis, on the other hand, is the result of ingestion of acid-producing compounds, problems with metabolism, or the loss of alkaline fluids from the body, the Merck Manual reports. Mild acidosis can cause fatigue, nausea and vomiting. More severe acidosis can cause a headache and drowsiness, which may progress to stupor, a coma and death.
Effects of Food
The acidity and alkalinity of different food products has recently come into focus by groups that claim that you can increase your overall health by consuming alkaline foods, such as fruits and vegetables. Because the body has its own regulatory system for maintaining blood pH, it is unlikely that changing your diet can have any significant long-term effect on the alkalinity of your blood, InteliHealth notes. As a result, there is not enough evidence to support the use of alkaline foods to treat any form of disease.