Various multi-layered physiological mechanisms act to ensure that the pH values of the cells, fluids, tissues, and organs of the body are properly maintained. They do so by neutralizing and eliminating excess acid buildup.
What follows is a simplified overview of how these mechanisms function:
There are several layered buffer systems within the cells and the blood that work to neutralize or buffer acid by-products. These buffer systems—known as the bicarbonate, phosphate, and protein buffer systems—help maintain stable cellular and blood acid-alkaline balance. The primary organs that work to eliminate acid buildup in the body are the kidneys and the lungs, followed, to a lesser extent, by the skin. Although some of these organs play a more significant role than others, they are all engaged in the important activity of preserving internal pH balance.
The kidneys help regulate acid-alkaline balance of the bloodstream by eliminating solid acids, also known as fixed acids—especially sulfuric and uric acid—through urination. When the levels of such acids become excessive, the kidneys excrete increased levels of hydrogen ions. This process acts as a filtering mechanism that dilutes the acids and moves them out of the bloodstream to be eliminated by the urine. In its excretion of acids, the kidneys utilize alkali reserve compounds, and if these are not available from the diet, the body calls upon alkali reserves stored in the watery layer around the bone and in the bone itself. At times, even the muscles are affected as muscle tissue is broken down to release an alkalizing amino acid called glutamine, which is used by the body in its pH recovery-rescue processes.
Excess acidity damages the kidneys
It is important to note that through the use of bicarbonate and other alkalizing compounds, the kidneys are able to accomplish their task of neutralizing and removing acids as long as proper acid-alkaline balance is maintained. These acids must be buffered with alkalizing compounds prior to their elimination, because without buffering, harsh concentrated acids with a pH of 4.5 or less would burn the delicate kidney tissues.
Limitations of kidney acid excretion
Regardless of how hard the kidneys work, or how efficient they are at producing and recycling alkalizing bicarbonate, these organs can rid the body of only a certain amount of acids each day. If the alkali reserves necessary for neutralizing acids are in short supply, while at the same time the body’s production of acids is high, a degree of acidosis, or acid buildup, occurs within the body. This buildup of acids beyond the kidneys’ capacity to eliminate them can set the stage for a wide variety of health problems, beginning with the disruption of proper cell function. Then, over time, numerous biochemical reactions are impaired and the stage is set for dysfunction and disease.
The role of the lungs
The lungs also work to keep the body’s pH levels balanced by eliminating volatile (gas-formed) acids. As you breathe, the carbon dioxide produced through metabolic processes inside the body combines with water in the blood. This combination produces carbonic acid, which the lungs then eliminate as part of the process of respiration, helping to keep overall acidity in check. One telltale sign that the body is becoming overly acidic is increased respiratory rate. This increase is caused by the body’s attempts to eliminate increased levels of carbonic acid. Conversely, if the body is overly alkaline—a condition known as alkalosis—the rate of breathing generally decreases. This is because the body is attempting to retain enough acids to reverse excess alkalinity and restore proper acid-alkaline balance. In the average individual, the production, neutralization, and excretion of gaseous volatile acids goes on unaffected by dietary practices. Just as important, this process generally does not add an acid load to the body.
The skin also eliminates acids
The skin, through its sweat glands, is the final organ responsible for eliminating acids.
The skin accomplishes this through perspiration, which helps to flush acids out of the body. However, the amount of acids the skin can eliminate is not as significant as the amount eliminated by the kidneys and lungs.
The body is capable of eliminating an average of only one quart of sweat every 24 hours, whereas it can eliminate one and a half quarts of urine. Moreover, sweat is unable to eliminate acids in the same concentrations that urine can. It is interesting to note that, since increased levels of acids contained in sweat can produce a strong smell, body odor produced by perspiration can be a strong indication of a state of over-acidity.