In response to my most recent blog post recounting yet another instance of a dog eating a large quantity of raisins and not getting sick, I received a most intriguing email from an independent researcher named Tina T. in Sweden.
It seems Tina learned about the grape toxicity in dogs issue only after she’d already been feeding grapes to her dog regularly for years. Like so many thousands of others, her dog had never done anything except beg for more when she was fed grapes, so Tina became suspicious that the myth may not be true.
So Tina began researching and learned what many of us already know — that there are very few documented cases of dogs getting sick or dying from eating grapes or raisins and that no substance in these foods had ever been isolated as the direct cause of the death or sickness. As she looked further, she found what appears to be a plausible explanation for these rare cases: Fluoride.
Is Fluoride the common denominator between grapes, dogs and pet food?
In her further research, she found that 1) fluoride is implicated in kidney problems (http://fluoridealert.org/studies/kidney07/) and 2) Commercial dog food contains higher than safe levels of fluoride (http://www.dogsnaturallymagazine.com/fluoride-in-pet-foods/ http://www.ewg.org/research/dog-food-comparison-shows-high-fluoride-levels)
Grapes also apparently have high levels of fluoride due to a fluoride based pesticide widely used on them called cryocide (marketed as Kryocide), which is even allowed to be used on organic grapes. Here is an excerpt from an article about fluoride in grapes from NaturalNews.com: “Since fluoride chemicals are persistent and do not biodegrade, they often build up in soils where plants uptake them into their roots, stems, leaves, and even their fruit. This has clearly been observed in grapes, for instance, which often contain levels of fluoride far higher than the U.S. Environmental Protection Agency’s (EPA) maximum contaminant level (MCL) for fluoride of four parts per million (ppm). Many domestic wines, in fact, have levels of fluoride so high that they cannot be exported to Europe and other places where MCL thresholds for fluoride are lower than they are in the U.S.”
Just as these chemicals are more concentrated in wine, they would be far more concentrated in raisins than in grapes. This would explain why raisins are much more often a problem than grapes in the rare cases where negative after effects are noted in dogs.
In dogs with kidneys that are already operating sub-optimally due to the presence of excessive fluoride in their daily food, it would make sense that these are the dogs who might have problems ingesting raisins. This also would explain why, according to the anecdotal evidence I’ve seen, raw fed dogs do not seem to have problems with grapes or even raisins.
The investigation that didn’t happen
There are many potential causes of renal failure in dogs, and many possible leads to follow up on. Rather than issuing premature and unfounded warnings, the vet industry needs to do the real scientific work which the consuming public blindly presumes it does. Btw if you are interested in more objective information on this topic, be sure to read my two previous blog posts on the ‘grape controversy’.