Barbara Demeneix R. Thomas Zoeller
Brain function, especially in children, is often evaluated by intelligence tests resulting in an Intelligence Quotient or “IQ.” IQ scores, after having increased for most of the 20th century, have been going down since the mid-1990s.
The
decline is well documented across Europe, the U.S. and Australia.
Is
this trend for real?
Some
technical issues related to IQ measurements may be playing a role. However,
scientific studies show that chemical exposures harm brain function in our
children.
Every
baby born in America (and in the developed world) is contaminated with
industrial chemicals and many professionals – including numerous medical and
scientific organizations – are focusing on the soup of chemicals in which we
raise our children. Many of these chemicals affect brain development,
especially endocrine-disrupting chemicals.
Reducing exposures to these mixtures of chemicals offers the single best approach to improving the mental and physical health of our children.
An
assault on our children
Endocrine-disrupting chemicals interfere
with our hormones. Newborn babies are pre-exposed to mixtures of more
than 200 endocrine-disrupting
chemicals. These include phthalates, perchlorate, fluoride, BPA (bisphenol-A) and its
substitutes, parabens, legacy
chemicals such as PCBs and DDT, and heavy metals including lead and
mercury.
What
is worse: these chemicals are in the amniotic fluid and surround the baby
during the first nine months of its life when the brain is forming at an
incredible rate with thousands of nerve cells born per second. Contamination
continues through the mother’s milk or formula, through the air the baby
breathes, in the creams, lotions and baby wipes used on its small body, and
more. This is an assault on our children – our species’ next generation.
The
major culprits in reducing IQ
Let’s
go through some of the worst offenders.
Consider phthalates. These chemicals are included in
many consumer products, personal care products, processed foods, food packaging
materials and medical supplies. Several studies have shown that exposure to
these chemicals causes reductions in
IQ. In addition, they have been found universally, from the Arctic to
Antarctica, including in different species from ants to alligators.
Perchlorate,
is a thyroid disruptor and found in rocket
fuel, fireworks and airbags, as well as in food packaging. It is
present in ground water and can be taken up through the food we eat.
Perchlorate acts by reducing the ability of the body to use iodine — an
essential ingredient in the formation of thyroid hormone. Perchlorate affects
IQ by suppressing thyroid function and producing a state of thyroid hormone
insufficiency.
Fluoride
that is often added to drinking water is another problem for brain development.
One of the most clear-cut demonstrations of the fluoride lowering effect on IQ
came from Canada. A study led by Christine Till measured
the IQ of Canadian children living in different cities. There was a stark
contrast in IQ, equivalent to 10
points, with lower scores in children that had fluoride in their drinking
water.
BPA
is the poster child of endocrine disruption, and its substitutes like BPS and
BPF are equally problematic. A recent study found the increase in BPS use in
thermal paper by 153% in a single year. Other studies on BPS exposure
show decreases in psychomotor function at two years of age associated with
increases in ADHD. Several studies have also shown that BPF decreases IQ, showing interference with the thyroid
system, which is essential for normal brain development.
The
chemicals PCBs and DDT are
considered “legacy” because their production was banned, but they both remain
in our environment. Both of these chemicals decrease IQ in children and adults that were exposed as children.
They act by interfering with the thyroid system.
Mercury
is known to damage brain development, including detrimental effects on IQ. An
example is the 2.5 IQ points lost in the cohort of exposed South
Korean children.
And the mixture of all of these chemicals – and more – contaminate our children from conception to adulthood.
Breaking
this vicious cycle
So
yes — we are getting dumber. And we are watching it happen, pretending that the
regulatory system that has overseen this debacle can reverse the trend.
While
focusing on IQ gives us a glimpse at what is happening, there are other trends
that are just as disturbing: the rise in attention deficit disorder and autism,
as well as other brain-based disorders.
Although
these trends will not be reversed overnight, we must find the political will to
reduce these exposures. The first step is for people to be aware of sources of
contamination and avoid those sources; however, there is no face mask for
endocrine disruptors. The next step is to empower regulatory agencies to
effectively monitor and decrease exposure to the most common.
The
science is established. We must prioritize our children’s health by reducing
environmental contaminants.
Barbara Demeneix an Emeritus professo of physiology and endocrinology at the National Museum of Natural History in Paris. R. Thomas Zoeller is an Emeritus professor of biology at the University of Massachusetts, Amherst.