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Acids and Bases
An acid is a substance that increases the concentration of hydrogen ions (H+) in water. A base is a substance that decreases the concentration of hydrogen ions, in other words, increasing the concentration of hydroxide ions OH-.
The degree of acidity or alkalinity of a solution is measured in terms of a value known as pH, which is the negative logarithm of the concentration of hydrogen ions:
pH = 1/log[H+] = -log[H+]
What is pH?
On the pH scale, which ranges from 0 on the acidic end to 14 on the alkaline end, a solution is neutral if its pH is 7. At pH 7, water contains equal concentrations of H+ and OH- ions. Substances with a pH less than 7 are acidic because they contain a higher concentration of H+ ions. Substances with a pH higher than 7 are alkaline because they contain a higher concentration of OH- than H+. The pH scale is a log scale so a change of one pH unit means a tenfold change in the concentration of hydrogen ions.
Importance of balancing pH
Living things are extremely sensitive to pH and function best (with certain exceptions, such as certain portions of the digestive tract) when solutions are nearly neutral. Most interior living matter (excluding the cell nucleus) has a pH of about 6.8.
Blood plasma and other fluids that surround the cells in the body have a pH of 7.2 to 7.3. Numerous special mechanisms aid in stabilizing these fluids so that cells will not be subject to appreciable fluctuations in pH. Substances which serve as mechanisms to stabilize pH are called buffers. Buffers have the capacity to bond ions and remove them from solution whenever their concentration begins to rise. Conversely, buffers can release ions whenever their concentration begins to fall. Buffers thus help to minimize the fluctuations in pH. This is an important function because many biochemical reactions normally occurring in living organisms either release or use up ions.
Oxygen: Too much of a good thing?
Oxygen is essential to survival. It is relatively stable in the air, but when too much is absorbed into the body it can become active and unstable and has a tendency to attach itself to any biological molecule, including molecules of healthy cells. The chemical activity of these free radicals is due to one or more pairs of unpaired electrons.
About 2% of the oxygen we normally breathe becomes active oxygen, and this amount increases to approximately 20% with aerobic exercise.
 Such free radicals with unpaired electrons are unstable and have a high oxidation potential, which means they are capable of stealing electrons from other cells. This chemical mechanism is very useful in disinfectants such as hydrogen peroxide and ozone which can be used to sterilize wounds or medical instruments. Inside the body these free radicals are of great benefit due to their ability to attack and eliminate bacteria, viruses and other waste products.
Active Oxygen in the body
Problems arise, however, when too many of these free radicals are turned loose in the body where they can also damage normal tissue.
Putrefaction sets in when microbes in the air invade the proteins, peptides, and amino acids of eggs, fish and meat. The result is an array of unpleasant substances such as:
Hydrogen sulfide
Ammonia
Histamines
Indoles
Phenols
Scatoles
These substances are also produced naturally in the digestive tract when we digest food, resulting in the unpleasant odor evidenced in feces. Putrefaction of spoiled food is caused by microbes in the air; this natural process is duplicated in the digestive tract by intestinal microbes. All these waste products of digestion are pathogenic, that is, they can cause disease in the body.
Hydrogen sulfide and ammonia are tissue toxins that can damage the liver. Histamines contribute to allergic disorders such as atopic dermatitis, urticaria (hives) and asthma. Indoles and phenols are considered carcinogenic. Because waste products such as hydrogen sulfide, ammonia, histamines, phenols and indoles are toxic, the body's defense mechanisms try to eliminate them by releasing neutrophils (a type of leukocyte, or white corpuscle). These neutrophils produce active oxygen, oddball oxygen molecules that are capable of scavenging disintegrating tissues by gathering electrons from the molecules of toxic cells.
Problems arise, however, when too many of these active oxygen molecules, or free radicals, are produced in the body. They are extremely reactive and can also attach themselves to normal, healthy cells and damage them genetically. These active oxygen radicals steal electrons from normal, healthy biological molecules. This electron theft by active oxygen oxidizes tissue and can cause disease.
Because active oxygen can damage normal tissue, it is essential to scavenge this active oxygen from the body before it can cause disintegration of healthy tissue. If we can find an effective method to block the oxidation of healthy tissue by active oxygen, then we can attempt to prevent disease.
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