TOXINS AND YOUR GOOD HEALTH
by Dr. Joe Schwarcz
Dr.
Joe Schwarcz is Director of McGill University’s Office for
Science and Society. He hosts The Dr. Joe Show on Montreal's CJAD
and has appeared hundreds of times on The Discovery Channel, CTV,
CBC, TV Ontario and Global Television. Dr. Schwarcz also writes
a newspaper column entitled The Right Chemistry and has authored
four best-sellers, Radar, Hula Hoops and Playful
Pigs, The Genie in the Bottle, That's The way The Cookie
Crumbles, and Dr. Joe And What You Didn’t Know..
______________________
Be warned! The
food, cosmetic and pharmaceutical industries commonly use an industrial
solvent that remains in the final product. It cannot be removed
from fruits or vegetables by washing and is used as a fire retardant,
stain remover and antifreeze ingredient. It is always found in
malignant tumors and is responsible for thousands of deaths every
year through inhalation. Surveys show that people become quite
indignant when informed of the widespread use of this chemical
and are quite willing to sign petitions to have it banned. But
banning dihydrogen monoxide would certainly not improve our life.
Water is hardly a poison! Yet everything I said is true, including
the thousands of deaths every year through inhalation, perhaps
better described as “drowning.”
It is obviously
easy to conjure up scary scenarios that will alarm people by using
scientific lingo selectively and inappropriately. Numerous publications
and websites do this as they warn us about hazardous chemicals
found in our foods, cosmetics and cleaning agents. We’re
told that parabens, commonly used preservatives in cosmetics,
are “estrogen mimics,” that polyethylene glycol, used
as a thickener in shaving cream and as an emollient in skin lotions
may be contaminated by 1,4-dioxane, a known carcinogen, and that
all perfumes contain toluene which can cause liver, kidney and
brain damage.
All of these statements
are technically correct but their practical relevance is highly
suspect. Remember that the pivotal credo of toxicology, first
voiced by Paracelsus in the sixteenth century, is that “only
the dose makes the poison!” Yes, perfumes do contain toluene,
but in amounts that are way below levels that cause any effect.
Evidence for the presence of a substance is not evidence of harm.
After all, we don’t avoid apples even though their seeds
harbour the deadly toxin cyanide, we happily eat strawberries
although they contain acetone, a known neurotoxin, and we are
not deterred from toast by the presence of 3,4-benzopyrene, an
established carcinogen. The toxic properties of these chemicals
are indeed real. When test animals are exposed to high doses of
acetone or 1,4-dioxane, they certainly do show neurological damage
and tumor growth. But that doesn’t mean small doses in humans
over a longer time will have a similar effect. In fact, they may
have a significantly different effect.
Buckle your seatbelts,
because we are going on a bumpy ride. We are going to rattle some
of the basic tenets of toxicology. Not only may tiny doses of
toxins not be dangerous, they may actually be good for us! Admittedly,
that sounds outrageous. So let’s set the stage for an exploration
of a revolutionary concept known as “hormesis,” the
notion that small doses of toxins can be healthful. Actually,
this may not be quite as surprising as it first appears. Vitamin
D in small doses is certainly healthy, but large doses can be
lethal. A glass or red wine a day may prolong health, a bottle
a day increases the risk of various cancers. But is it possible
that exposure to tiny doses of really toxic substances, such as
dioxins or pesticides, may actually lead to a better functioning
immune system? Ed Calabrese, professor of toxicology at the University
of Massachusetts thinks this is a real possibility. And he is
no academic slouch. Dr. Calabrese has published over 500 research
papers and is recognized as the world authority on exposure to
trace chemicals.
Calabrese originally
got interested in low dose toxins when as an undergraduate he
became involved in a project to investigate the amount of herbicide
needed to stunt the growth of peppermint plants. Much to his surprise,
the plants grew taller when sprayed with the chemical. It turned
out that the solution had been improperly prepared and was far
more dilute than intended. Years later, at a conference on radiation,
Calabrese was reminded of his peppermint plants when he learned
that studies had shown people exposed to low level radiation lived
longer and had lower cancer rates. He then began to scour the
scientific literature for other such effects and came up with
almost 6000 publications that had documented dramatically different
effects at very low concentrations of toxins when compared with
those seen at higher doses. Rats exposed to traces of the insecticide
DDT or the treacherous pollutant dioxin, developed fewer liver
tumors than unexposed rats. Bacteria frolicked when treated with
trace amounts of antibiotics.
Hormesis (from
the Greek “to excite”) of course is still controversial,
because if such effects are real, we may have to reevaluate our
exposure standards for contamination of air, water, food and soil
by certain chemicals. It does, however, make biological sense.
When an organism is attacked by poisons, it responds by unleashing
a variety of molecules, mostly enzymes, which attempt to repair
the damage. If the amount of toxin is minute, there may be an
over reaction, with more defense chemicals being churned out than
needed, leaving an excess to deal with the molecular insults of
everyday life. It may yet turn out that the apocalyptics who warn
us of the perils of exposure to parts per trillion of “toxic”
chemicals are on the wrong track. Of course, nobody is suggesting
doping our body with traces of DDT or dioxin, but information
is accumulating that the paranoia about trace amounts of toxins
in our environment is unjustified.
And just to show
you how far irrational chemophobia can spread, the city of Aliso
Viejo in California nearly banned styrofoam cups when a paralegal
working for the City Council chanced upon a “professional
looking” website that listed the evils of dihydrogen monoxide
and described its use in the production of styrofoam. The Council
was ready to ban styrofoam until someone pointed out that the
evil chemical was just water.
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