Dear EarthTalk: I don’t eat meat, for a variety of ethical and environmental reasons, and I’d rather not feed it to my cat, either. Do cats have to be carnivores?

-- John McManus, Needham, MA

Unlike dogs and other omnivores, cats are true (so-called “obligate”) carnivores: They meet their nutritional needs by consuming other animals and have a higher protein requirement than many other mammals. Cats get certain key nutrients from meat—including taurine, arachidonic acid, vitamin A and vitamin B12—that can’t be sufficiently obtained from plant-based foods. Without a steady supply of these nutrients, cats can suffer from liver and heart problems, not to mention skin irritation and hearing loss.

As such, a cat’s ideal diet is made up mainly of protein and fats derived from small prey such as rodents, birds and small reptiles and amphibians. Some cats munch on grass or other plants, but most biologists agree that such roughage serves only as a digestive aid and provides limited if any nutritional value.

Of course, providing your domestic cat with a steady stream of its preferred prey is hardly convenient or humane—and cats can wreak havoc on local wildlife populations if left to forage on their own. So we fill them up on dry “kibble,” which combines animal products with vegetable-based starches, and meat-based canned “wet” foods, many containing parts of animals cats would likely never encounter, much less hunt and kill, in a purely natural situation. Most cats adapt to such diets, but it is far from ideal nutritionally.

Veterinarian Marla McGeorge, a cat specialist at Portland, Oregon’s Best Friends Veterinary Medical Center, argues that the problem with forcing your cat to be vegetarian or vegan is that such diets fail to provide the amino acids needed for proper feline health and are too high in carbohydrates that felines have not evolved to be able to process. As to those powder-based supplements intended to bridge the nutritional gap, McGeorge says that such formulations may not be as easily absorbed by cats’ bodies as the real thing.

Some would vehemently disagree. Evolution Diet, makers of completely vegetarian foods for cats, dogs and ferrets, says that its meatless offerings, on the market for 15 years, are healthy and nutritious, and, if anything, have extended the lives of many a feline and canine, even reversed chronic health problems. Claiming that most mainstream pet foods contain artery-clogging animal fat, diseased tissue, steroid growth hormones and antibiotics no less harmful to pets than to humans, its website posts testimonials from loyal customers who claim happy and long-lasting pets who look forward to their meals.

And Harbingers of a New Age, which makes “Vegecat” kibble and supplements that provide cats with nutrients otherwise only found in meat, says that its products allow owners to “prepare food in your own kitchen, choosing recipes that fit your lifestyle.”

The vegetarian pet debate is a contentious one among vegetarian pet owners and veterinarians and is one not likely to go away anytime soon. The best approach may well be to give some of the non-meat supplements and/or foods a try. If your cat won’t eat them, or does not do well on them—take kitty to a veterinarian for a check-up to see—you can always go back to what you were feeding her before.

CONTACTS: Best Friends Veterinary Medical Center, www.bestfriendsdvm.com; Evolution Diet, www.petfoodshop.com; Harbingers of a New Age, www.vegepet.com.

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