HUMAN DISEASES IN
Michael W. Fox
Minnesota, I am in one of the epicenters of the nation-wide epidemic of
obesity, diabetes and related degenerative and endocrine diseases
afflicting the human population, many of which I witness every day when out in
public. I find it particularly disturbing when health experts, including those
in universities and the federal government, simply call for more public
education with regard to eating habits and life style, telling people to eat
more fruits and vegetables and get more exercise, because other factors are
involved in this epidemic.
This health crisis is mirrored in many of the letters that I receive from
readers of my nation-wide syndicated newspaper column Animal
Doctor who have cats
and dogs suffering from similar health problems. The underlying factors
responsible for turning companion animals into environmental sentinels--- or
latter day canaries down the proverbial mine shaft, ---alerting us to harmful
chemicals in the environment we share, are beginning to be identified.
Indiana University scientists Drs. M. Venier and R.A.Hites have reported that
they have found toxic flame retardant chemicals in the blood of pet dogs at
concentrations five to 10 times higher than in humans. The study focused on the
presence of polybrominated diphenyl ethers, (PBDEs), compounds widely used as
flame retardants in carpets, household furniture foam, plastics and electronics
equipment that can migrate out of the products and enter the home environment.
These chemicals are also found in pork, chicken, butter and seafoods.
In their summary of this important study these scientists state:“A previous
study from our laboratory showed that pet cats had much higher serum levels of
flame retardants compared to humans, despite sharing the same household
environment. Dogs, on the other hand, are expected to have lower serum levels
of flame retardants because they are metabolically better equipped to degrade
these compounds. Thus, we hypothesized that dogs might be more similar to
humans in their response to these environmental stressors and be better
indicators of human exposures to these contaminants. Serum samples and their
food were collected from 18 dogs and analyzed for PBDEs and other emerging
flame retardants. The concentrations of PBDEs in dog serum and dog food
averaged 1.8 ± 0.4 ng/g wet weight (ww) and 1.1 ± 0.2 ng/g ww, respectively.
While the dog serum samples were dominated by the tetra to hepta BDE congeners,
BDE-209 was the most abundant congener in the dog food. This difference in
congener pattern was analyzed in terms of half-lives. Assuming food as the main
exposure source, the average half-life in dog serum was 450 ± 170 days for the
less brominated congeners and 2.3 ± 0.5 days for BDE-209. Dust was also
considered as an additional exposure source, giving unreasonable residence
times. In addition to PBDEs, other flame retardants, including Dechlorane Plus,
decabromodiphenylethane, and hexabromocyclododecane, were identified in these
An earlier study by a research team lead by Dr. Janice A. Dye showed evidence
linking thyroid disease in cats with exposure to PBDEs, which the researchers
found to be elevated in blood samples of hyperthyroid cats. Their findings were
based on analysis of blood samples from 23 pet cats, 11 of which had feline
hyperthyroidism. PBDE levels in the hyperthyroid cats were three times as high
as those in younger, non-hyperthyroid cats.
Olga Naidenko, Rebecca Sutton, Jane Houlihan with the Environmental Working
Group published a report in April 2008 entitled high Levels of Toxic Industrial
Chemicals Contaminate Cats and Dogs. They summarized their study as follows:
Dogs and cats were contaminated with 48 of 70 industrial chemicals tested,
including 43 chemicals at levels higher than those typically found in people,
according to our study of plastics and food packaging chemicals, heavy metals,
fire retardants, and stain-proofing chemicals in pooled samples of blood and
urine from 20 dogs and 37 cats collected at a Virginia veterinary clinic.
Average levels of many chemicals were substantially higher in pets than is
typical for people, with 2.4 times higher levels of stain- and grease-proof
coatings (perfluorochemicals) in dogs, 23 times more fire retardants (PBDEs) in
cats, and more than 5 times the amounts of mercury, compared to average levels
in people found in national studies conducted by the Centers for Disease
Control and Prevention (CDC) and EWG.----For nearly all the chemicals included
in the current study, health risks in pets have not been studied. But the
chemicals are linked to serious health effects in other studies from laboratory
data or human populations:
- For dogs, blood and
urine samples were contaminated with 35 chemicals altogether, including 11
carcinogens, 31 chemicals toxic to the reproductive system, and 24
neurotoxins. The carcinogens are of particular concern, since dogs have
much higher rates of many kinds of cancer than do people, including 35 times
more skin cancer, 4 times more breast tumors, 8 times more bone cancer,
and twice the incidence of leukemia, according to the Texas A&M
Veterinary Medical Center (2008). Between 20 and 25 percent of dogs die of
cancer, making it the second leading cause of death in dogs (Purdue
University Department of Veterinary Pathobiology 2000).
- Cat samples contained
46 chemicals altogether, including 9 carcinogens, 40 chemicals toxic to
the reproductive system, 34 neurotoxins, and 15 chemicals toxic to the
endocrine system. Endocrine (hormone) system toxins raise particular
concerns for cats, since they include the thyroid toxins and fire
retardants called PBDEs. Thyroid disease (hyperthyroidism) is a leading
cause of illness in older cats (Gunn-Moore 2005). The growing use of PBDEs
in consumer products over the past 30 years has paralleled the rising
incidence of feline hyperthyroidism, and a preliminary study suggests that
PBDEs are found at higher levels in cats stricken with this disease (Dye
2007). Studies also show a high correlation between eating canned food and
developing hyperthyroidism later in life for cats (Edinboro 2004; Kass
1999, Martin 2000). In addition to PBDEs, hyperthyroidism in cats could be
linked to the plastics chemical and potent endocrine disruptor BPA that is
known to leach from the pop-top cat food can lining into food (Edinboro
2004; Kang 2002).
High levels of flame retardant
chemicals have been found in pregnant women, in breast milk and in children,
and are implicated in the development of diabetes, obesity, and thyroid
disease---common afflictions also of dogs and cats---and may adversely affect
prenatal brain development in humans, and therefore of animals whose mothers
are exposed to these same chemicals. One of the potent effects of PBDEs on the
body is called endocrine disruption, an effect shared with other chemicals also
contaminating food and home environments, notably pthalates and Bisphenyl A in
plastics, food containers and food can linings; dioxins, PCBs, and
organochloride pesticides that are common contaminants of various foods and
drinking water. Some 86% of air fresheners, widely used in homes and offices,
tested by the Natural Resources Defense Council contained phthalates.
Recent tests of Chicago city tap water, for example, found
perfluorooctane sulfonate, an ingredient in Scotchgard stain-fighting coatings,
bisphenol A and tris (2-butoxyethyl) phosphate, a flame retardant chemical.
Perchlorate, an ingredient in rocket fuel, fireworks, and explosives, can
disrupt the thyroid gland’s production of hormones essential to prenatal and
postnatal development and body metabolism, and is often present in municipal
compounds, like those
manufactured for decades by the 3M Company, have been found to contaminate the
food chain, fish in particular, as well as our home environments. They are widely-used water,
stain repellents found in carpets and on clothes, on fast-food wrappers, and on
the inner lining of pet food bags. Teflon, Scotchgard, Stainmaster and Gore-Tex
products contain PFCs. Some personal care products contain PFCs.
water, are persistent in the environment, and remain in the human body for
years. PFCs have been associated with cancer, reproductive problems, birth and
developmental defects, and (recently) with immune system suppression.
Dogs: High levels of plasticizers, grease-proof chemicals, and fire retardants. 35 chemicals detected
- 40% at higher levels in dogs than people.
Cats: notably high levels of fire retardants, high levels of plasticizers, and grease-proofing chemicals.
46 chemicals detected - 96% at higher levels in cats than people.
charts summarize the findings in the report by the Washington DC-based
Environmental Working Group, High Levels of Industrial Chemicals Contaminate
Cats and Dogs (April 17, 2008, http://www.ewg.org)
Endocrine disruptors play a role in
the development of diabetes Type 2 and thyroid disease (hypothyroidism and
hyperthyroidism). In the past four years, diabetes rates among dogs in the U.S.
increased roughly 33% among dogs and 16% among the nation's cat population, per
a national analysis of pet health. This is associated with obesity, many pets
being overweight according to a 2010 Banfield Pet Hospital report.
The U.S. President’s Cancer Panel Annual Report for 2008-2009 will disturb many
chemical manufacturers and other industry sectors with its bold assertion that
since environmental toxins, especially chemicals, are the main cause of cancer,
tighter regulations are long overdue. Home owners, parents and pet owners
(since cancer is a major cause of death in cats and dogs) can take many steps,
avoiding any questionable household cleaners and other products; drinking
filtered/purified water; not using plastic food and beverage containers with
harmful bisphenol A (BPA) and pthalates (also in many toys); washing
conventionally grown produce to remove cancer-causing pesticides and chemical
fertilizers if organically grown foods are not available; and minimizing
“exposure to antibiotics, growth hormones and toxic runoff from livestock feed
lots by eating free-range meat raised without these medications if available.”
The report also advises “Avoiding or minimizing consumption of processed,
charred, and well-done meats will reduce exposure to carcinogenic (compounds)”.
For details go to www.environmentalhealthnews.org/ehs/news/presidents-cancer-panel.
Regrettably this report failed to stress that the widespread use of lawn and
garden pesticides and herbicides should be prohibited in every municipal
Glyphosate-based herbicides, residues of which are in foods, have been shown to
cause birth defects in laboratory animal tests, and many widely used
agricultural pesticides are endocrine-disruptors causing infertility, abnormal
genitalia and feminization, and could play a significant role in the genesis of
various cancers. Lawn herbicides, which should be banned, are linked to
lymphatic cancer in exposed dogs. These agrichemicals may also play a role in
honey bee colony collapse, which is becoming a global epidemic and could mean
ecological devastation and food shortages since one-third of our food crops
need to be pollinated by insects.
The problems caused by the above kinds of chemicals have helped create a
multibillion dollar market for weight loss and control programs, liposuction
and other surgeries, special diets for afflicted people, dogs and cats, as well
as costly drugs that are not without their own harmful side effects. While a
sickened populace may profit the health care industry, it is bankrupting state
and federal health care services for the poor and uninsured, and families with
escalating medical costs.
Recognition of these hazardous chemicals in the food chain, drinking water and
our home environments and the health problems that they can trigger calls for
far more than simply changing what we eat and feed to our pets, and giving them
and ourselves more exercise. State and federal government involvement,
regardless of opposition from the chemical industry and related
manufacturers of goods and foodstuffs, in addressing the long overdue
environmental clean-up of the offending chemicals, needs to be sustained and
intensified with better funding and expert staffing. Greater public awareness
and appropriate action through informed consumer decision-making and home
environment assessment and clean-up as needed are also part of the long-term
solution to what is now a serious and costly public and companion animal health
Filters: Conventional water treatment
does not screen out many unregulated contaminants, but some household filters
can help. Reverse osmosis won’t help get volatile organic compounds out of your
water, according to the National Sanitation Foundation, but carbon filtration
will. Water filtration products are certified by NSF International, a nonprofit
group. Visit nsf.org.
Food & Water Storage/Containers: Avoid all plastics, and with canned cat
& dog foods, most 5.5oz cans are not lined with bisphenol A containing
resins, while most larger sized cans still have this kind of lining.
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