In article ,
wrote:

the problem is ... this is anecdotal. There are no controlled studies
showing the
toxicity of grapes. the dog is sick, people bring in the dog, the vet
asks what the
dog ate, and what the human can remember renders it anecdotal.
obviously, lots of
dogs, foxes and wolves eat grapes without getting sick or dying. they
love them,
dont have an aversion which is expected if they were routinely toxic as
evolution
takes care of instilling avoidance. why grapes may be toxic for some
dogs is not
understood. SO FAR, no toxic compounds have been found in grapes. No
scientific
studies have been done. Ingrid

"Val" wrote:
http://www.snopes.com/critters/crusader/raisins.asp


The vet's article of one case is not a controlled study and the fact that
the vet says there are no published studies on this topic (when there are)
indicates you're quite right that this particular vet's testimony is
evidence of nothing at all. And the fact that a thousand lay articles can
be found hysterically warning about poisonous grapes should be taken
seriously only after checking for authentic sources of this information
beyond grandma-told-me or i-heard-it-somewhere.

However, if that vet HAD bothered to do a search for support data, there's
plenty.

Eubig et al in the Journeal of Veterinarian Internal Medicine Sep/Oct 2005
reports on 43 such cases in the AnTox database 1992-2002. All the reported
dogs had the same clinical signs of poisoning (vomiting, diarrhea,
lethargy & loss of apetite) & the majority were testably hypercalcemic &
hyperphosphatemic. So there is a clear-cut no-guesses-required method of
assessing toxicity from grapes or raisins. The Eubig study could not
identify the specific mechanism for renal failure, but the toxic cause &
effect were unquestionable.

Morrow et all in the Journal of Veterinary Diagnostic Investigation, May
2005, looked at ten cases of renal failure in dogs caused by injestion of
grapes or raisens. These ten dogs had severe symptoms of renal
degeneration or necrosis. Very aggressive treatment & care was no
guarantee of a good outcome. Again the specific toxin(s) could not be
identified but that something in grapes caused calcium homeostasis & renal
system shut-down was unquestionable.

Elwood & Whatling in Veterinary Record April 8 2006 looks at several
reported cases of renal failure in dogs associated with raisins & grapes.

A half dozen other studies could be cited in veterinarian & nutrition
journals. While your statement "no toxic compounds have been found" is at
least partially true, several have been named as possibilities. There are
too many flavinoids in grapes, any one of which alone or in combination
could be the culprit, & since it's not believed to impact human health
there is never going to be sufficient funding to isolate them all & test
them one by one on dogs. The toxicity to dogs of grapes & raisins,
however, is unquestionable, even though the specific flavinoid or
flavinoid compound is unknown.

So too the specific triggering mechanism in the the animal's body is
poorly understood, but seems to be related to platelet production, heart
response, & ability to expell calcium. The mechanism is unclear but the
ultimate outcome (renal failure) is not in question.

Grapes or raisins have to be ingested in large quantities to have any
effect at all. There's probably no risk in giving them one grape now &
then, but if they went through a whole box crate of them, severe illness &
death could be expected.

Other studies show the same response of renal failure in dogs that have
eaten lilies or lily bulbs. So too garlic & onions can cause toxicity in
dogs (and cats) if eaten in a large enough quantity, but if you gave a dog
a small bit a table scrap of something cooked with onions included, it
would come nowhere near a toxic level. Brocoli if it exceeds 10% of diet &
especially when it reaches around 25% of diet is also notably toxic to
dogs & many other animals, but in small amounts MIGHT actually be
beneficial.

Knowing the possibilities I would not give my wee beloved Daigoro any
grapes. But if he grabbed just one without permission & gobbled it down, I
would not hasten him to the veterinarian.

I applaud your cynicism & suspicion that urban folklore is at work. But
careful review of the scientific data indicates that for once the common
masses have learned something that's correct.

-paghat the ratgirl
--
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"In every country and in every age, the priest has been hostile to
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