You already know that the air is polluted. Everybody is subjected to toxic exposure from a wide variety of pollutants in the air they breathe. Among the many toxins in the air are:

1. Carbon monoxide and lead from fuel exhaust (most of the lead has been reduced in the United States, but it is still found elsewhere).
2. Hydrocarbon pollutants from industrial waste.
3. By-products from the burning of fossil fuels.
4. Radiation leakage from nuclear power plants and radon in the home. Radiation, like radon gas, is a contaminant that cannot be seen, smelled, or tasted and is therefore more insidious than some of the more familiar pollutants.

Tap water, unfortunately, contains more than water. It is often contaminated with toxic heavy metals such as lead or cadmium or with fluoride (associated with an increased risk of cancer, digestive disorders and kidney disease). Often, industrial chemicals and wastes, pesticides and other farm chemicals have seeped through the soil to contaminate the water table. Volatile chemicals (those hydrocarbons that readily vaporize) can combine with chlorine to form even more toxic products.

You may be familiar with the toxic chemical water contamination in Woburn, Massachusetts, which led to increases in childhood leukemia. Other examples abound. (I recommend a solid carbon-block water filter, or spring water, for all drinking and cooking needs.) Unfortunately, in spite of home filtration or spring water for personal use, there is always some exposure to tap water, such as when you eat at restaurants or buy prepared foods, or when you shower and breathe the vaporized volatile chemicals. (At one water testing lab, the joke about their municipal water was that it was "safe" to drink, but for goodness sake don't smoke in the shower!)

Cigarette smoke exposure in smokers and nonsmokers (sidestream smokeÑthe uninhaled pollutants from the end of the cigaretteÑand secondhand smoke are also highly toxic) creates further health risks. This and most pollutants lead to an increase of high-energy molecular fragments known as free radicals. These free radicals can severely damage tissues, destroy nutrients, and lead to premature aging, heart disease and cancer. All of these environmental problems increase your need for nutrients, and many supplements can help control the damage of toxic exposures.

The Damage from Free Radicals
In the normal course of metabolism, your body produces small, high-energy particles that have a single electron in their outer shell (such molecules are unstable because electrons prefer to be paired). These are called free radicals, and they can be very damaging in their search for another electron. Free radicals derived from oxygen are the most abundant and damaging of the species.

These free radicals are normally channeled into energy production. In some cells they may be used as the weapons to kill viruses and bacteria. Unfortunately, if too many of them are produced, their extremely high energy can also be damaging to normal tissues. Free radicals disrupt the normal production of DNA, the genetic material, and alter the lipids (fats) in cell membranes. They also affect the blood vessels and the production of prostaglandins. (Prostaglandins are hormone-like substances that regulate many physiological functions, and their production is very sensitive to many metabolic influences.)

We are also exposed to free radicals that are found in the environment or generated by exposure to environmental chemicals. There are many sources of excess free-radical exposure, including cigarette smoke; air pollution; some highly processed foods and food additives; ultraviolet sunlight and radiation; processed oils such as commercial vegetable oils, margarines and shortenings; charcoal-broiled foods and any charred or burned foods; heavy metals (lead, cadmium, aluminum, and mercury) found in processed foods; excessive iron; pesticides; and some prescription medications. Many of the chemicals found in municipal water supplies are toxic because they generate free radicals. It is good to drink a lot of water but to avoid tap water as much as possible.