canned food and hyperthyoidism?

The following appears in "Catnip," the newsletter from Cummings School of
Veterinary Medicine at Tufts University, January 2006, Vol. 14 No. 1. It is
part of an article titled "Spotlight on Vital Cat studies" by Karen Lee
Stevens which includes an interview with Duncan C. Ferguson, VMD, PhD. It is
in a question and answer format. Below is the introduction and an excerpt
from the article:

"Duncan C. Ferguson, VMD, PhD, a veterinarian who is board-certified in
clinical pharmacology and internal medicine at the University of Georgia,
has investigated hyperthyroidism in cats, since 1978.
Q. As to a possible cause of hyperthyroidism in cats, can you briefly
describe your theory?
A. Other researchers have found a correlation between cats fed a canned food
diet and incidences of hyperthyroidism. This may have something to do with
the fact that cats do not metabolize certain kinds of compounds very well.
Some of the compounds used to make the plastic liner in a cat food can have
compounds called plasticizers. It is these types of structures that cats
tend to be pretty slow at metabolizing. They may accumulate and influence
thyroid glandular growth and function, most likely, by altering circulating
concentrations of TSH."

I hope Phil P, Steve Crane, and any veterinarians on the group will comment
on this.

Annie

Annie Wxill wrote:
The following appears in "Catnip," the newsletter from Cummings School of
Veterinary Medicine at Tufts University, January 2006, Vol. 14 No. 1. It is
part of an article titled "Spotlight on Vital Cat studies" by Karen Lee
Stevens which includes an interview with Duncan C. Ferguson, VMD, PhD. It is
in a question and answer format. Below is the introduction and an excerpt
from the article:

"Duncan C. Ferguson, VMD, PhD, a veterinarian who is board-certified in
clinical pharmacology and internal medicine at the University of Georgia,
has investigated hyperthyroidism in cats, since 1978.
Q. As to a possible cause of hyperthyroidism in cats, can you briefly
describe your theory?
A. Other researchers have found a correlation between cats fed a canned food
diet and incidences of hyperthyroidism. This may have something to do with
the fact that cats do not metabolize certain kinds of compounds very well.
Some of the compounds used to make the plastic liner in a cat food can have
compounds called plasticizers. It is these types of structures that cats
tend to be pretty slow at metabolizing. They may accumulate and influence
thyroid glandular growth and function, most likely, by altering circulating
concentrations of TSH."

I hope Phil P, Steve Crane, and any veterinarians on the group will comment
on this.

Annie


Hi Annie,
This controversy has pretty much died as a result of newer
information and recognition of what an epidemiological study is all
about. Epi studies are very important - but have severe limitations.
They are important in giving us clues for future research. In an Epi
study like this one, it is possible to look at thousands of animals and
then record historical data about those animals habits. In this case
Dr. Ferguson noted that hyperthyroidism was higher in cats being fed
canned foods that had "pop-top" lids. Pop top lids work by having a
very thin plastic like barrier under the top of the can lid. It was
hypothesized that this plastic barrier might leach into the foods and
cause hyperthyroidism.
Subsequent testing of most major manufacturers foods did not find
the chemical present in the food. An Epi study gives us a good place to
start looking, but should NEVER be taken as establishing a causal
relationship. One of my favorite examples of the fundamental failure of
any Epi study is the following:

My father ate green peas as a child, he died of colon cancer at age 34,
therefore green peas cause colon cancer.

While the first two parts of this statement are true - they do not make
the third part of the statement true. Epi studies work much the same
way. Looking for some causal relationship - in this case green peas.
Cats fed from pop-top cans may have many other similarities in addition
to being fed from pop-top cans. Are pop-top can fed cats more likley to
be fed:
1. higher protein levels than cats fed commerical dry food.
2. fed by pet owners who have less time to spend with cats, and perhaps
less excersize.
3. fed by owners who are more careful of thier cats and take them to
the vet more often
4. fed by owners who are less careful of thier cats and don't take them
to the vets.
5. more likely to be overweight due to being pampered by pet owners

I don't know if many of these things are true, but they serve as
examples of the dozens of other possibilities that cats fed pop-top
cans might have in common as well and might impact the cats health.

In December a year ago Dr. Karen Wedekind published her patent on
hyperthyroid cats and within that patent was an understanding that
higher protein levels may contribute to hyperthyroidism in cats due to
increases of certain trace elements that are intrinsic to increased
protein in cat foods. It isn't the increase in protein, but rather the
increase in a couple trace minerals that come along with the protein
materials.

"Annie Wxill" wrote in message
...

The following appears in "Catnip," the newsletter from Cummings School of
Veterinary Medicine at Tufts University, January 2006, Vol. 14 No. 1. It
is
part of an article titled "Spotlight on Vital Cat studies" by Karen Lee
Stevens which includes an interview with Duncan C. Ferguson, VMD, PhD. It
is
in a question and answer format. Below is the introduction and an excerpt
from the article:

"Duncan C. Ferguson, VMD, PhD, a veterinarian who is board-certified in
clinical pharmacology and internal medicine at the University of Georgia,
has investigated hyperthyroidism in cats, since 1978.
Q. As to a possible cause of hyperthyroidism in cats, can you briefly
describe your theory?
A. Other researchers have found a correlation between cats fed a canned
food
diet and incidences of hyperthyroidism. This may have something to do
with
the fact that cats do not metabolize certain kinds of compounds very well.
Some of the compounds used to make the plastic liner in a cat food can
have
compounds called plasticizers. It is these types of structures that cats
tend to be pretty slow at metabolizing. They may accumulate and influence
thyroid glandular growth and function, most likely, by altering
circulating
concentrations of TSH."

I hope Phil P, Steve Crane, and any veterinarians on the group will
comment
on this.

Annie,

A few of these studies have been published in the past few years- one said
cats that ate canned fish or liver and giblets had an increased risk of
hyperthyroidism- another said pop-top cans increased the risk, and another
just said eating canned food increased the risk. These are all
epidemiologic studies rather than clinical medical studies. Also, the
results were based on owner observation rather than on hard medical data.

None of these dubious claims have ever been supported by actual chemical
tests on cat blood or T4 that could explain how canned food or the coating
on the inside of the cans can cause hyperthyroidism. None of the chemicals
in the coating were ever found in the food and no differences were ever
found in cat food that was packaged in cans or glass.

I've been feeding canned food for more than 40 years and only one of my cats
ever developed hyperthyroidism. I don't think people should stop feeding
canned food because of the results of these types of studies. I sure won't.

Phil

"Steve Crane" wrote in message
oups.com...
....
Hi Annie,
This controversy has pretty much died as a result of newer
information ...
In December a year ago Dr. Karen Wedekind published her patent on
hyperthyroid cats and within that patent was an understanding that
higher protein levels may contribute to hyperthyroidism in cats due to
increases of certain trace elements that are intrinsic to increased
protein in cat foods. It isn't the increase in protein, but rather the
increase in a couple trace minerals that come along with the protein
materials.

Steve,
Thanks for your detailed reply.

I understand how wrong conclusions can result from the juxtaposition of two
(or more) true observations.

I would expect to see better reporting and/or editing in a newsletter that
comes from a vet school at a well-known and respected university. Although
they are not in the same category as what appears in scientific journals, I
would hope that the information such newsletters provide to the general
public would be current and accurate.

What are the trace minerals that come along with the protein and what
amounts of those minerals would be optimal?

Thanks again,

Annie

"Phil P." wrote in message
k.net...
Annie,
....
None of these dubious claims have ever been supported by actual chemical
tests on cat blood or T4 that could explain how canned food or the coating
on the inside of the cans can cause hyperthyroidism. None of the
chemicals
in the coating were ever found in the food and no differences were ever
found in cat food that was packaged in cans or glass.
.... Phil

Thanks Phil,

As I said in my reply to Steve Crane, I think that although it is not a
scientific journal, I would expect that a newsletter from a well-known vet
school owes its readers information that is as current as possible and not
misleading.

I wonder if anyone will call them on it.

I'm sorry to have to snip the majority of your reply. My news server, or
reader, or whatever it is, will reject messages if my reply is a lot shorter
than your message.

Annie

Annie Wxill wrote:
"Steve Crane" wrote in message
oups.com...
...
Hi Annie,
This controversy has pretty much died as a result of newer
information ...
In December a year ago Dr. Karen Wedekind published her patent on
hyperthyroid cats and within that patent was an understanding that
higher protein levels may contribute to hyperthyroidism in cats due to
increases of certain trace elements that are intrinsic to increased
protein in cat foods. It isn't the increase in protein, but rather the
increase in a couple trace minerals that come along with the protein
materials.

Steve,
Thanks for your detailed reply.

I understand how wrong conclusions can result from the juxtaposition of two
(or more) true observations.

I would expect to see better reporting and/or editing in a newsletter that
comes from a vet school at a well-known and respected university. Although
they are not in the same category as what appears in scientific journals, I
would hope that the information such newsletters provide to the general
public would be current and accurate.

My guess would be that it was designed for veterinarians who would
recognize an Epi study for what is was. Perhaps they didn't / don't
realize that there is a wider audience reading the newsletter.


What are the trace minerals that come along with the protein and what
amounts of those minerals would be optimal?

selenium at 0.65 mgs/kg and iodine - I don't have the patent on this
machine and can't remember the values, but it probably wouldn't do much
god anyway as I doubt many manufacturers can or would provide the
levels in the foods they produce. At this point I wouldn't get too
worried about it.


Thanks again,

Annie

"Steve Crane" wrote in message
ups.com...
My guess would be that it was designed for veterinarians who would
recognize an Epi study for what is was. Perhaps they didn't / don't
realize that there is a wider audience reading the newsletter.
....
The publication says on the header that it is "The Newsletter for Caring Cat
Owners." It is a monthly publication that covers a number of subjects of
interest. For example, the issue in question also has articles on adopting
special needs cats, introducing dogs and cats, new products (litter box
scoops, toys, etc.), and IBD.

I suspect that Dr. Ferguson's comments, if any, about how the research was
conducted and correlation was made, were omitted by the writer or cut for
space by the editor.

The next question asks "What is the goal of your study?"
Dr. Ferguson answers, "Our goal is to obtain a valid, documented
glycopeptide standard for feline TSH and to characterize its behavior with
some immunological reagents we had already developed against dog TSH. A
sensitive non-invasive test is needed to aid in earlier and more accurate
diagnosis of hyperthyroidism. By including the accurate measurement of TSH
in the diagnostic procedures for hyperthyroidism, we should be able to
detect the disease in its early stages."

Annie

"Annie Wxill" wrote in message
...

"Steve Crane" wrote in message
ups.com...
My guess would be that it was designed for veterinarians who would
recognize an Epi study for what is was. Perhaps they didn't / don't
realize that there is a wider audience reading the newsletter.
...
The publication says on the header that it is "The Newsletter for Caring
Cat
Owners." It is a monthly publication that covers a number of subjects of
interest. For example, the issue in question also has articles on
adopting
special needs cats, introducing dogs and cats, new products (litter box
scoops, toys, etc.), and IBD.

I suspect that Dr. Ferguson's comments, if any, about how the research was
conducted and correlation was made, were omitted by the writer or cut for
space by the editor.


The article in Catnip was based on studies that were actually published in
the Journal of the American Veterinary Assoc. So, technically, they can
"back up" the article with "scientific documentation". I think publishing
an article like that for pet owners was very poor judgment. Catnip should
have stated that the article was based on mail-order, owner-opinion
epidemiological studies rather than
controlled, clinical medical studies and that no causal association between
canned food and hyperthyroidism has *ever* been found.

Because Tufts is a credible institution, many people will accept the
article as gospel and I'm afraid they will needlessly switch their cat's
food to dry.

There's also a study in the Journal of Veterinary Internal Medicine that
implies 2-3-fold increase in risk of hyperthyroidism in cats fed canned food
and a 3-fold increase in risk of hyperthyroidism in cats that use litter.
With more than 60 million cats using litter- hyperthyroidism should be
reported in epidemic proportions! I'm sure a study could find an increased
risk of some diseases in cats that are petted between 9 am and 10 am than
cats petted between 2-3 pm- if you get my drift.





The next question asks "What is the goal of your study?"
Dr. Ferguson answers, "Our goal is to obtain a valid, documented
glycopeptide standard for feline TSH and to characterize its behavior with
some immunological reagents we had already developed against dog TSH. A
sensitive non-invasive test is needed to aid in earlier and more accurate
diagnosis of hyperthyroidism. By including the accurate measurement of
TSH
in the diagnostic procedures for hyperthyroidism, we should be able to
detect the disease in its early stages."


A test for early detection of hyperthyroidism and for when T4 is falsely
depressed due to other illneness already exists- its called Free T4 by
Equilibrium Dialysis and costs about $20. The blood sample is dialyzed
before its assayed. Sounds like Fergy is trying insure his job security by
trying to drum up funding for a study.

Merry Christmas

Phil

"Phil P." wrote in message
ink.net...
...I think publishing
an article like that for pet owners was very poor judgment. Catnip should
have stated that the article was based on mail-order, owner-opinion
epidemiological studies rather than
controlled, clinical medical studies and that no causal association
between
canned food and hyperthyroidism has *ever* been found.
... Because Tufts is a credible institution, many people will accept the
article as gospel and I'm afraid they will needlessly switch their cat's
food to dry.
... A test for early detection of hyperthyroidism and for when T4 is
falsely
depressed due to other illneness already exists- its called Free T4 by
Equilibrium Dialysis and costs about $20. The blood sample is dialyzed
before its assayed. ...
Phil

Merry Christmas back to you, Phil.

In addition to hyperthyroidism, the article included information about
research of diabetes, cancer of the oral cavity, the effects of lysine on
upper-respiratory disease and urinary diseases.

I agree that poor judgment was made in publishing, at least the portion we
have discussed here, and not mentioning the type of study. It certainly got
my attention because I want to feed our cats what is best for them
(although, they don't always agree) with an emphasis on canned food. But,
they do want their "crunchies" and I'll give them a few before bedtime. I
know they would prefer that we switch from canned to dry, but I've learned
too much from this group about the risks involved, which is why I questioned
the information presented in the article.

I suspect that the article tried to cram too many topics into too little
space and left out some important points.
You'd expect more care and better editing from a well-known and respected
institution because not everyone will question what is presented.

However, I do believe that the topic of the article, which was an overview
of some research on certain diseases, was good. I expect that more detailed
information on each of these topics will be published in later issues.
Overall, I think the publication is good and I have subscribed for many
years.

Annie