Learning and Developmental Disabilities Linked to EnvironmentalToxins

http://www.healthsentinel.com/org_ne...st_item&id=128

Roman Bystrianyk, "Learning and Developmental Disabilities Linked to
Environmental Toxins", Health Sentinel, February 25, 2008,

Autism, attention deficit hyperactivity disorder (ADHD), dyslexia,
mental retardation, lowered IQ and other learning and behavior
disorders are very common in today's American children. The occurrence
of these learning and developmental disabilities (LDDs) appears to be
rising with between 5 to 15 percent of all children under the age of
18 in the United States affected. In general, these disabilities have
significantly increased over the past 40 years and now affect more
than 12 million children in the United States.

On February 20, 2008 The Collaborative on Health and the Environment's
Learning and Developmental Disabilities Initiative published a
Scientific Consensus Statement on Environmental Agents Associated with
Neurodevelopmental Disorder. This statement signed by more than 50
national and international health professionals and scientists
summarizes the most recent science about environmental contaminants
associated with learning and developmental disabilities. The report
that was drafted by this prestigious group contains over 200
scientific references.

"We know enough now to move on with taking steps to protect our
children. This document pulls that knowledge together to further this
vital effort," said reviewer Martha Herbert, PhD, MD, an assistant
professor of neurology at Harvard Medical School and a pediatric
neurologist with subspecialty certification in neurodevelopmental
disabilities at the Massachusetts General Hospital in Boston.

Exposure to a wide variety of chemicals is now an unavoidable fact of
modern life. Approximately 3,000 chemicals are manufactured in amounts
over 1,000,000 pounds each year. The vast majority of these chemicals
have little to no information on their potential to effect learning
and development. According to the report, "there is good evidence that
about 200 of these chemicals are adult neurotoxicants and another
1,000 are suspected of affecting the nervous system. Overall there has
been a gross failure to require developmental neurotoxicity testing."

Historically, of all the factors that contribute to learning and
developmental problems, chemical contaminants have been the least
studied, although ironically the most preventable. The report states
that, "we now have solid scientific evidence that a variety of
environmental agents can adversely affect the nervous system," and
that "a child's developing nervous system is more sensitive to
chemical exposure than the adult nervous system."

Children that lack certain nutrients are more susceptible to these
chemical toxicants. For instance, iron and/or calcium deficiencies can
affect the absorption and toxicity of heavy metals such as lead and
manganese. "The role of nutrition in mitigating exposure to
environmental agents is an important public health issue."

The following environmental contaminants have been "conclusively
shown" to affect the developing nervous system and cause a range of
performance deficits.

Alcohol - The effects of alcohol on the brain are well recognized.
"Fetal Alcohol Syndrome (FAS), now considered part of the Fetal
Alcohol Spectrum Disorder (FASD), is the most preventable form of
behavioral and learning disabilities. Even low or moderate consumption
of alcohol during pregnancy can cause subtle and permanent performance
deficits."

Mercury - There is no doubt that mercury causes learning and
developmental disorders. "We are all exposed to some form of mercury.
Inorganic mercury is the liquid silver form and is used in dental
amalgams. Mercury is also present in coal, and coal-burning electric
utilities facilities are a significant source of atmospheric
environmental mercury."

PCBs - Polychlorinated biphenyls (PCBs) are mixtures of chlorinated
compounds that were once used as cooling and insulating fluids in
electrical transformers and other electronic components. "Numerous
studies have documented that PCB exposure can adversely affect motor
skills, learning and memory as shown in lower full-scale and verbal IQ
scores and reading ability."

PBDEs - Polybrominated diphenyl ethers (PBDEs) have been used commonly
as flame-retardant chemicals for years. "Recent studies have left
little doubt that PBDEs are developmental neurotoxicants in animals
and lead to changes in motor activity and reduced performance on
learning and memory tests."

Manganese - Manganese is a trace element which is essential in small
quantities for normal growth and development. "Recent studies indicate
that high levels of manganese exposure, either from inhalation or
through drinking water, can damage the developing nervous system."

Arsenic - Arsenic is frequently found in drinking water around the
world. "Recent studies have found a dose-response relationship between
exposure to arsenic and intellectual impairment. While additional
studies assessing the impact of low levels of arsenic in drinking
water are needed, it is clear that arsenic affects the
neurodevelopment of children.

Solvents - Solvents include a broad array of different compounds
including toluene, benzene, alcohol, turpentine, acetone and
tetrachloroethylene. More than 50 million metric tons are used in the
United States with more than 10 million people exposed in the
workplace. "Several reports have documented that the adverse
developmental effects of maternal toluene exposure include low birth
weight, decreased head circumference and developmental delays."

PAHs - Polycyclic aromatic hydrocarbons (PAHs) are widely dispersed
air pollutants and well-recognized human mutagens and carcinogens.
PAHs are generated during combustion of fuels from motor vehicles,
coal-fired power plants, residential heating and cooking and are also
present in tobacco smoke. "Recent studies have indicated that elevated
exposure to PAHs results in lower birth weight and affects cognitive
development."

Pesticides - Pesticides are ubiquitous in our modern environment.
Agricultural and residential application of pesticides totals more
than 1 billion pounds each year in the United States. "There is now
evidence that childhood exposure to pesticides, such as
organophosphates, enhances the risk for developmental disorders
including deficits in memory, poorer motor performance and an array of
other conditions."

Nicotine and environmental tobacco smoke (ETS) - Many studies link
maternal smoking to behavior disorders in children. The developmental
delays caused by ETS are costly and preventable. "Furthermore, new
data indicates that childhood exposure to ETS is associated with
neurobehavioral effects. There is growing recognition of subsequent
behavioral disorders in young adults following exposures either
prenatally or as children."

Unfortunately, it is not possible to address all the chemicals that
might be associated with LDDs. Again, it's important to note that for
the majority of chemicals "we do not have the data necessary to
conclude there are no adverse developmental effects." There are an
estimated 200 chemicals that are known to cause neurotoxic effects in
adults, but for many of these chemicals "developmental effects have
not been examined."

The following are number of agents that are of significant concern:

Endocrine disruptors - "Animal studies have documented that a wide
range of chemicals have the ability to disrupt endocrine function in
animals and affect cognitive function. Endocrine disruptors include
phthalates, PCBs and polychlorinated dibenzodioxins, brominated flame
retardants, dioxins, DDT, perfluorinated compounds (PFCs),
organochlorine pesticides, bisphenol A and some metals. The
controversy around the effects of endocrine disruptors is perhaps best
illustrated by research on bisphenol A whose estrogenic activity was
first reported in 1936. It was subsequently found to stabilize
polycarbonates and resins and is now widely used in many products
including food-can liners. There is a growing body of evidence related
to the very low-dose effects of bisphenol A"

Fluoride - Fluoride is commonly added to drinking water across the
United States in an effort to reduce dental decay. Fluoride is also
found in a range of consumer products including toothpastes and
mouthwashes. "Excessive fluoride ingestion is known to lower thyroid
hormone levels, which is particularly critical for women with
subclinical hypothyroidism: decreased maternal thyroid levels
adversely affect fetal neurodevelopment. In addition, a study in China
reported decreased child IQ levels associated with fluoride in
drinking water. The primary concern is that multiple routes of
exposure, from drinking water, food and dental care products, may
result in a high enough cumulative exposure to fluoride to cause
developmental effects."

Food additives - Artificial food colors and additives are found
throughout the modern food supply and have long been suspected as
causing conduct disorders. Diets, such as the Feingold Diet removes
food additives from the diets of individuals with ADHD. "Previous and
recent carefully conducted double-blind human studies have confirmed
that artificial food colorings such as sunset yellow, tartrazine,
carmoisine and ponceau, as well as the preservative sodium benzoate,
can cause conduct disorders. Recent studies using well-designed
randomized, double-blind, placebo-controlled, crossover trials show
that artificial food colors and additives cause increased
hyperactivity in three-year-old children. This has the potential to
become a serious issue given the large number of children diagnosed
with ADHD."

"Accepting childhood exposure to contaminants that result in
compromised learning and behavioral abilities violates the basic
tenets of biomedical ethics. The principle of beneficence ("do good")
requires that the benefits be maximized while the harm be minimized or
eliminated. Respect for autonomy or personhood is violated when
children are unnecessarily exposed to harmful substances. Respect of
person also implies informed consent, and no child has given the
informed consent for exposure to harmful chemicals. Finally, the
principle of justice requires that burdens be shared equally, and
because children are more vulnerable they endure a greater burden. It
is wrong to allow the exposure of children to environmental agents
that cause learning and developmental disorders."

We are still dealing with the health effects of adding lead to paint
and gasoline, even though at the time the toxic effects of lead were
well known. "To protect children, a precautionary approach is required
that shifts the burden of responsibility to producers or manufacturers
to demonstrate safety prior to potential exposure."

"We could cut the health costs of childhood disabilities and disease
by billions of dollars every year by minimizing contaminants in the
environment," said Phil Landrigan, MD, MSc, of the Children's
Environmental Health Center at the Mount Sinai School of Medicine.
"Investing in our children's health is both cost-effective and the
right thing to do."

"The overwhelming evidence shows that certain environmental exposures
can contribute to life-long learning and developmental disorders,"
noted Ted Schettler, MD, MPH, with the Science and Environmental
Health Network. "We should eliminate children's exposures to
substances that we know can have these impacts by implementing
stronger health-based policies requiring safer alternatives. Further,
we must urgently examine other environmental contaminants of concern
for which safety data are lacking. "

"The proportion of environmentally induced learning and developmental
disabilities is a question of profound human, scientific and public
policy significance," said lead author Steven G. Gilbert, PhD, DABT,
of the Institute of Neurotoxicology & Neurological Disorders, "and has
implications for individuals, families, school systems, communities
and the future of our society. The bottom line is it is our ethical
responsibility to ensure all children have a healthy future."

The authors of the study do not include all the hazards that affect
the brains of our children. Nutritional deficiencies of omega-3 fatty
acids, B vitamins, selenium, vitamin E, and others are documented in
the medical literature as affecting brain health and development. The
avoidance of dairy, wheat, and artificial sweeteners in the diet have
been shown to positively change neurologic problems. Excessive
television viewing has also been associated with behavior and
attention problems. Thimerosal, found in vaccines and other products,
has been shown that it "induces oxidative stress and apoptosis by
activating mitochondrial cell death pathways" and to have "induced DNA
strand breaks, caspase-3 activation, membrane damage and cell
death" (NeuroToxicology, Vol. 26, 2005)

The authors conclude, "The scientific evidence we have reviewed
indicates environmental contaminants are an important cause of
learning and developmental disabilities. The proportion of
environmentally induced LDDs is a question of profound human,
scientific and public policy significance. Existing animal and human
data suggest that a demonstrated with scientific certainty. The
consequences of LDDs are most significant for the affected individual
but also have profound implications for the family, school system,
local community and greater society. Despite some uncertainty, there
is sufficient knowledge to take preventive action to reduce fetal and
childhood exposures to environmental contaminants. Given the serious
consequences of LDDs, a precautionary approach is warranted to protect
the most vulnerable of our society."

The over 50 scientists of this report state they are developing a
companion document outlining specific policy recommendations based on
the current scientific knowledge that was used to assemble this
report.

We as individuals can act now. We can avoid alcohol and tobacco smoke.
We can get water and air filters to minimize exposure to lead,
mercury, and other contaminants. We can avoid using pesticides on our
lawns and by choosing to eat organic foods. We can avoid processed
foods that contain artificial colors and ingredients. We can use
fluoride free products. We can use natural cleaners that don't contain
harmful solvents in our homes. We can use products that don't contain
phthalates and other harmful chemicals. We can ensure we get enough
nutrients by avoiding nutritionally deficient junk foods and focus on
getting enough omega-3 fatty acids and key vitamins and minerals in
our diets. We can minimize our exposure to television and instead
focus on positive activities such as exercise, reading, playing, and
creating.

We can make the changes that help our children and reverse course on
an epidemic of neurologic problems. We can make a difference one life
and one child at a time if we have the ethics and will to do so.

SOURCE: Scientific Consensus Statement of Environmental Agents
Associated with Neurodevelopmental Disorders, http://www.iceh.org/pdfs/LDDI/LDDIStatement.pdf