MANY CALIFORNIA GRAPEVINES ARE TREATED WITH CRYOLITE,
A FLUORIDE-BASED PESTICIDE
Melissa learned that wine from California grapes can contain high amounts of fluoride due to the use of the pesticide cryolite on grapevines. Cryolite is a fluoride-based chemical pesticide consisting of a mixture of aluminum, sodium and fluoride. It has been used as a pesticide primarily on grape and raisin crops for quite some time.
Melissa decided to write to all the regional winery associations in the state to ask if they used cryolite. Most said they'd never heard of it, or claimed not to use it. Some even told her retailers wouldn't sell it for fear fluoride would leech into residual ground water.
One of the associations she contacted sent her a link to the online monitoring program of the California Department of Pesticide Regulation, where farmers are required to report which pesticides they use. At the link, she was able to learn exactly where cryolite is used in California.
RAISINS GROWN IN CALIFORNIA ALSO TREATED WITH CRYOLITE
As it turns out, the use of cryolite is limited to the Central Valley. "It's in a region known as the San Joaquin Valley," says Melissa, "which is outside of Fresno. It's also the self-proclaimed 'raisin capital of the world.'"
"That really raised a red flag with me. I knew raisins are toxic to dogs. I wondered if veterinarians had investigated the possibility that cryolite is the cause of the toxicity. That's really when I started looking at the research that veterinarians had done and saw that there was no reference to cryolite or fluoride, and they really weren't even thinking in that vein."
The timeline for all this is interesting, because raisin toxicosis in pets is relatively new. Many years ago when taking my dogs to training classes, we were told to use grapes or raisins as training treats, because they were the perfect size and lower calorie than store-bought treats. Then just a few years later, it became a huge no-no because dogs were being diagnosed with kidney disease after eating grapes and raisins.
DID THE USE OF CRYOLITE COINCIDE WITH THE UPTICK IN RAISIN TOXICITY CASES?
According to Melissa, the Environmental Protection Agency (EPA) originally approved cryolite in the 1980s, but it was already in use by that time, so it's been around for probably 40 years at least. When the EPA approved cryolite, the agency admitted there were extensive data gaps regarding its toxicity.
It was 1989 when veterinarians began noticing the trend of raisin toxicity in dogs, which happens to be the same year Europeans noticed high amounts of fluoride in the wine they were importing from California. The EU had a limit of 1 part per million. Pesticide manufacturers lobbied to get an increase to 3 parts per million in wines made from grapes treated with cryolite, but even with the increase, they weren't always able to meet European requirements.
"Clearly, wine had high amounts of fluoride by 1989," says Melissa, "and that's also when veterinarians noticed that raisins were toxic to dogs. It's not clear whether that's when dogs started dying from eating raisins, in 1989, or maybe just their databases started showing that trend at that time. Before that, people used raisins for dog treats all the time without any known issues."
SHOULD WE START TESTING DOGS WITH RAISIN TOXICITY FOR ELEVATED LEVELS OF FLUORIDE?
Melissa believes the easiest way to confirm or refute her theory is to test for fluoride in dogs with raisin toxicity. Test the animal's urine and blood, as well as a sample of the raisins that were ingested or the bar code on the package of raisins if available, to see if there are elevated levels of fluoride.
Many state veterinary teaching hospitals will be able to measure fluoride levels, or pet owners can do their own research and refer their veterinarian to a lab that can. This testing should help determine if a dog is suffering from fluoride toxicity rather than raisin toxicity. This makes perfect sense to me. As an integrative veterinarian, I'm always digging a little deeper, looking for hidden causes for an animal's suffering. I'm always suspicious that man-made and other foreign substances are creating illness and disease in my patients.
As for raisins and grapes, wild dogs such as coyotes and wolves have been known to forage on grapes. In fact, in some parts of the world they eat them regularly and don't seem to develop acute renal failure.
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FLUORINE TOXICITY IN PLANTS