Some Startling New Thoughts on Cats and Hairballs


Published by: Ingrid King. Last Updated on: February 7, 2023 by Crystal Uys

Guest post by Fern Slack, DVM

It is always the case that we vets deal with the same problems at home that we counsel our clients about. And not always terribly well. I’m certainly no exception. Years ago, I had a long-haired cat who threw up hairballs frequently, but unlike most hairball-barfing cats, she did not just hack up the offending wad and then go about her business as though nothing had happened. Nope, she would obviously feel ill for minutes to hours afterward. And probably beforehand, too, had I had the vision to see it.

I tried all the time-honored remedies that I prescribed every day for my patients. I dosed her with various brands of flavored petroleum jelly. I fed her diets purporting to help with hairballs by the inclusion of extra fiber. I brushed her constantly, which fortunately she loved. None of these things helped. Eventually I shaved her, leaving the adorable puffs on her legs and tail that made her look like a fat little old lady in tight leotard and legwarmers. As long as I did this three or four times a year, there were no more hairballs. Oddly enough, however, she continued to have vomiting episodes, albeit less frequently, and minus the hair. Diagnostics revealed inflammatory bowel disease, and eventually my poor sweet girl succumbed to intestinal lymphoma.

While rooming with a brilliant feline practitioner at a medical conference shortly after, still grieving, I confessed my frustration with the seemingly insignificant problem of hairballs. Her answer blew me away. There is no such thing as “just a hairball,” she says to me. Think about it. Cats developed stringent grooming behaviors in the course of evolution because grooming is a positive survival factor, probably through controlling parasitism and other diseases. So they are going to ingest a lot of hair. Does vomiting as a daily method for expelling this hair seem evolutionarily sound? Stomach acid hurts the esophagus and teeth, and frequent vomiting upsets the electrolyte balance. While vomiting as an emergency mechanism to rid oneself of the occasional nastiness seems reasonable, it seems unlikely that the daily vomiting of hairballs is the “normal” thing that the medical community has assumed it to be.

I’m hooked. Go on, I say. She continues.

Why would we think that “lubrication” of the gut with petroleum products would help? A cat is not a car. And in no way could a cat have naturally evolved to require the dosing with “lubricants” to survive or to thrive. Likewise, cats in the wild would never eat a “high-fiber” diet, and so would seem unlikely to benefit from one. On the contrary, it would appear logical that a cat would thrive better on what a cat has been evolved to eat – namely a mouse or a reasonable facsimile thereof – and that feeding a cat something wildly different from the diet it has evolved on is more likely to result in harm than in good.

No, she says, I think it likely that a “hairball,” far from normal, is probably a common early symptom of Inflammatory Bowel Disease. Impaired motility of the gut would account for the balling up of hair that should pass right through, if stomach-emptying time is the 0.2 – 2 hours it is reported to be in a normal cat. A cat shouldn’t be able to swallow enough hair fast enough to outrace normal stomach emptying time.

This is making sense to me. Particularly as I just lost my own cat to this. And as I think back, I realize that “hairballs” have been in the histories of a disproportionate number of the patients I’ve treated with IBD and lymphoma.

She tells me that she’s been changing her patients over to low-fiber diets (grain-free and low carbohydrate) for a while now, and she’s seeing a precipitous drop in the whole “hairball” thing. I can see the long-term implications of this line of reasoning: if cat food containing an unnaturally high level of fiber and carbohydrates is associated with an increased incidence of impaired GI motility and vomiting, and if cats fed this way are at higher risk to develop IBD and lymphoma, then a drop in hairball vomiting might mean that a cat has a lower risk of these two nasty diseases. Sounds as though a grain-free diet might be a better way to go.

This all made sense to me. No science to it back then, but neither was there any to support the idea that hairballs are normal. No one had at that time asked if a carbohydrate-based diet could possibly have long-term negative consequences for cats.

Well, they have now. Every day, there’s more scientific evidence that these “mere” hairballs we see so often may respond, not to grease and not to fiber, not to brushing and not to shaving, but to feeding a diet that looks like what a cat was evolved to eat.

In the intervening years, I’ve changed my own cats over to grain-free, low-carb canned foods, and I’ve seen nary a hairball from anyone for a very long time. In my esteemed colleague’s footsteps, I’ve been changing my patients over to these same diets. I hear about fewer hairballs, and my patients are slimmer, fitter, and healthier in many ways. Is this a panacea? Of course not. There’s no one cure for everything. But I now have serious trouble believing that a feline diet in which the calories are derived primarily from carbohydrates, which are much cheaper than proteins, is beneficial to anything other than the manufacturer’s bottom line.

So next time someone tells you that malt-flavored grease, fiber additives, brushing or shaving are the only ways to help with those annoying hairballs, think again. Hairballs may be more than just a stinky mess for you to clean up. They might well be a sign that your cat has a real health problem, and should see the veterinarian. And your cat might be telling you that her gut would be happier with “mouse” than with breakfast cereal.

Dr. Slack graduated from the College of Veterinary Medicine at the University of Georgia, and has been working exclusively with cats since 1993. She is the owner of Uniquely Cats Veterinary Center in Boulder, CO.

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