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Detoxification 101Toxicology is one area of medicine about which clinical ecologists are not in conflict with their more conventional colleagues. We share the same issues, pursue the same phenomena and agree on therapeutic approaches. Toxicologists tend to veer in the direction of epidemiological effects, studying whole-groups, whereas the clinical ecologist takes it more patient by patient, but that?s the only real difference. Toxicology has been around a surprisingly long time. Primitive peoples used natural poisons for hunting. Indeed the word toxicology comes from toxicos, the bow from which poison arrows were flung. The ancient Greeks and Romans made a special study of poisons, although more in connection with political assassinations than the pursuit of science. The Persian King Mithridates was so afraid of being poisoned that he took a regular cocktail of known poisons to accustom his body to their effect so that they would no longer work on him. From his name we get the word mithridate. The prolific use of poisons for getting rid of "inconvenient" people led to a treatise by Maimmonides (1135-1204) entitled Poisons and their Antidotes. It summarized all knowledge of poisons at that time. The Italian fifteenth-century Borgia family were infamous poisoners. Lucrezia?s name, in particular, achieved evil notoriety for her nefarious use of chemicals to "alter" history. Toxicology finally adopted a more formal scientific footing, and today we are concerned almost entirely with environmental hazards and unintentional harm done to human beings. Around 4,000,000 man-made chemicals have been described in scientific literature since 1965. Something like 6,000 new chemicals are added to the list every week and at least 70,000 are currently in production. Only a fraction of this toxic load has been adequately tested for the long term effects on human health. We meet chemicals in the air, our food, water supplies and by direct contact. Medical drugs add their share, and even the clothes we wear and the fabric of our homes are mostly artificially made, needing many complex chemical precursors. Some of these emit toxins long after being installed in the home. It is a fact of life in the modern world that indoor pollution can be just as bad, or worse, than the outdoor kind. The cumulative effect of all these substances may create a total body burden that triggers chemical sensitivity in certain individuals. In the late 1970s Dr. E.C. Hamlyn coined the term ?human canary? to describe such people ? they are a warning to us all that we are going to be ill if we continue as we are, in much the same manner that canaries used to warn miners of impending gas danger. Unfortunately, no one seems to be heeding these canaries. Most studies done on humans to date have been concerned predominantly with acute massive exposures suffered by workers in industrial settings, but clinical ecologists have been gathering case studies steadily to show that chronic exposure to levels commonly thought to be ?safe? are compromising people?s health and may turn out to be a more important hazard in the long term. MULTIFACTORIALThe effects of chemical exposure are dependent upon a number of factors, principally:
The resulting problems can be complex, depending on the target organs involved. Misdiagnosis and missed diagnosis are the norm. Safety levels are misleading, since they are based on averages. Some individuals will react to far lower levels than would affect the majority. The way the body disposes of unwanted and toxic compounds (xenobiotics) we call detoxification. In fact, the metabolic pathways discussed here, by which chemicals are inactivated and removed from the body, don?t always result in a less poisonous end-product. A better term, therefore, is biotransformation. There are several pathways involved. The subject is a vast and burgeoning one; the information given here is necessarily selective. METABOLISM OF TOXIC COMPOUNDSTo get rid of a toxin effectively it is most important that the body turns it into something soluble in water. At that point the substance or its metabolites (breakdown products) can be removed via the kidneys, sweat, bile and other fluids. There are two principal routes by which the body does this. In Phase I metabolism the molecule is altered by enzymes in a variety of ways, each process assisted by a specific enzyme. These enzymes are found in the microsomes of most cells. The most important of these enzyme pathways is the cytochrome P450 system, also called the multi-function oxidase system (MFO). Under its influence oxygen is added to the toxic molecule, converting a hydrogen atom in the molecule into a hydroxyl group (hydrogen and oxygen). The opposite effect, known as reduction, means that hydrogen is added. Both effects can knock out the toxicity of a molecule. Two other methods to note are: adding a water molecule (2 hydrogen and 1 oxygen atoms), called hydration and knocking out halogen atoms, such as chlorine, called dehalogenation. It is important to note that magnesium is essential for Phase I actions, as is a complex co-enzyme called nicotinamide adenine dinucleotide (NADH), a derivative of vitamin B3. Vitamin C and zinc are also said to help, and possibly other nutrients as well. This is why vitamin and mineral supplements can be so vital for allergics and poor metabolizers. Phase II detoxification is carried out differently. Here extra groups are stuck on to the basic molecule. These change its character and render it harmless and more soluble. We call this process conjugation. An example is sulphation, the addition of a sulphate group (-SO3). Phenol (carbolic acid), which looks like this:
Is converted into phenyl sulphate, which looks like this:
The enzyme in this case is sulphonyl transferase. Phenol sulphonyl transterase may have great importance for food intolerance since it has become clear that a number of foods contain several phenolic compounds. A study published in January 2004 found pollution, in particular, diesel exhaust, could significantly worsen symptoms in allergy sufferers. The study, which appeared in The Lancet, showed that when patients were exposed to diesel exhaust in addition to an allergen, histamine production increased by five-fold. And these effects were magnified in people with a particular genetic makeup. People with a mutation to the gene responsible for making an enzyme known as glutathione S-transferase M1 (GSTM1) responded even more strongly to the combination of diesel exhaust and allergen, the researchers found. As many as 50% of people are born with this mutation, says the study's lead author, Dr. Frank Gilliland, a professor of preventive medicine at the Keck School of Medicine at the University of Southern California.
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