When researching recently to write a review of Cat Attract litter, a litter that both I and my test cats liked for several reasons, I found something that rang a bell of alarm. I discovered in Dr. Elsey's (the developer of Cat Attract) FAQ section on his web site that Cat Attract uses sodium bentonite for its clumping abilities. In response to a question about the safety of clumping clay, he writes:
Yes [it is safe]. Concerns that bentonite clays will "set-up" in a cats stomach are un-founded. Over half of the litters sold today include bentonite clay and have proven safe for cats since their introduction over fifteen years ago. In fact, the convenience of clumping clays have contributed greatly to the growth of cats as pets. In Dr. Elseys 23 years as a feline only veterinarian, he has never had a case where clumping litters have caused a problem with a cat.
Many readers are aware that clumping clay litters have come into disfavor in recent years. While, to my knowledge, there have never been any scientific studies proving the hazard to cats of clumping clay litters, there has been a flood of anecdotal testimony that clumping clay litters may be hazardous. Indeed, I personally have considered it important to warn cat lovers about the potential danger of using clumping clay litters containing sodium bentonite.
In doing extensive research on the Net, for the Cat Attract review, I have found that the whole furor over clumping clay apparently originated on the web site of one individual, Marina McInnis, in her article, Clumping Clay Litters: a Deadly Convenience? McInnis is a breeder who tragically lost one or two litters of kittens in the mid 1990s. She later determined that the cause was the ingestion of clumping clay litter, which caused intestinal blockage from the clumping clay. In her original article, she cited confirmation from her own holistic veterinarian, along with supporting information from another holistic health practitioner. Ms. McInnis also cited communication with another breeder who had encountered similar problems, confirmed with that breeder's holistic veterinarian (also second-hand information.)
To back up her own experiences, McInnis includes letters from readers who reported similar problems with their own cats. Some of the letters referred to the writers' veterinarians or laboratories finding clay in stools of cats with bowel problems, but other than a letter from a veterinary assistant/receptionist, I did not see any confirmation from veterinarians. The most compelling evidence Marina McInnis presented, other than her own anecdotal experience, was a reprint of an article on suspected Bentonite toxicosis, which originally appeared in the Journal of Veterinary and Human Toxicology in June, 1997. Even that article resulted in a critical letter by another veterinarian - the full exchange can also be read on McInnis's web site.
Most other articles I was able to locate on the hazards of clumping clay referred back to Mcinnis's articles. One article also mentioned that the AVMA has never seen a documented case, but I have not been able to confirm that, either. The few articles I found on veterinary sites that mentioned clumping clay did so in a conservative manner. Not surprisingly, certain "premium" cat litter manufacturers have been able to use the clumping clay controversy to their advantage in promoting their own "safe" clumping litters.
On the other side of the coin, I have found few articles alluding to the safety of sodium bentonite in cat litter, other than by those manufacturers that still use it, such as Cat Attract and Simplicity.
Next > The rise and fall of clumping clay litters