Monthly Archives: September 2007

Eight strikes against fishy feeding

In the last few months, my email inbox has been full of inquiries from people asking about feeding fish to cats. To my mind, there are just too many arguments against feeding fish regularly to make it a safe, healthy choice as a staple of a cat’s diet.

As a treat once in a great while? Maybe. If you must. But know a few things first.

There are a number of problems–some well established facts and others that are somewhat open to question–that make feeding fish regularly, whether raw or cooked, pretty gosh darn inadvisable. At least from the digging I’ve done. The problems stem both from what’s in fish and what’s not in fish.

So far, I count eight distinct ‘strikes’ against the idea of feeding fish, raw or cooked, to cats.

Strike One: Low calcium levels.

Whole fish, even with bone, is far too low in calcium for a cat. Remember: if you’re making homemade cat food, one of the most important things to get right is the ratio of calcium to phosphorus. You have some wiggle room here, but not much. A whole ground fish would be low in calcium. And while the high phosphorus is not good for any cat, elevated phosphorus levels are something you most definitely wouldn’t want to feed a cat that is suffering from any kind of kidney problem.

Strike Two: Thiamin destruction.

Raw fish contains high amounts of an enzyme called thiaminase–an enzyme that destroys Vitamin B-1 (thiamin). A thiamin-deficient diet can lead to neurological problems and seizures in cats. No good.

Strike Three: Urinary tract problems.

Fish, with its high magnesium content, can contribute to a type of urinary tract problem in cats.

(While I’m on urinary troubles, let me interject something here. Curiously, the discovery some time back of magnesium as a culprit in feline urinary tract disorders was accompanied by the development of specialized ‘urinary tract’ formula foods. The idea with these foods was to add acid to the food, reasoning that magnesium crystals develop in alkaline, not acid urine. The problem is, cats whose urinary tract acid is too high are prone to another type of crystal–calcium oxylate. Just another reason it’s best to feed a cat a diet that nature intended. As Dr. Elizabeth Hodgkins points out in her book, the rise of urinary tract diseases in the cat coincided exactly with the increasing use of dry kibble to feed cats. But I digress.)

Strike Four: Addiction.

Heaven knows, cats absolutely adore the taste of fish. Anyone who’s ever opened up a can of fish within a 12-city-block radius of any hungry feline knows that. But you can quickly end up with a ‘fish addict’ on your hands. And the last thing you need is a cat on a hunger strike refusing to eat anything but an inferior fish diet.

Strike Five: Heavy metals.

There is a great deal of persuasive research suggesting that predatory fish (those at the very top of the food chain and the same ones often found in pet food or used as ‘treats’ for cats) have extremely high levels of heavy metals such as mercury–in addition to pesticides and other toxins. A 2004 study published in Acta Neuropatholgica discovered neurological disturbances in young kittens fed tuna daily that contained the US FDA-approved level of mercury (0.5 ppm).

Strike Six: Possible link to hyperthyroidism.

A US Environmental Protection Agency (EPA) study in 2007 revealed a disturbing link between feline hyperthyroidism and the chemicals in fire retardants–that mimic thyroid hormones–and cats’ consumption of fish. In the study, cats eating canned fish were exposed to polybrominated diphenyl ethers (PBDEs) that were five times higher than cats eating poultry or beef canned foods.

Strike Seven: Vitamin E depletion.

Felines love tuna, but eating it long term can deplete a cat’s stores of vitamin E and create conditions that lead to an extraordinarily painful condition called steatitis, with symptoms such as hypersensitivity to touch and loss of appetite. Huuuuuge bummer for the cat and for you. You’ll find tuna in lots of cat foods for the very reason that it’s tasty to cats and draws them to the food. But it has nothing to do with healthy, safe, or necessary nutrition for cats.

Strike Eight? Allergenic.

Fish are allergenic. To my mind, it just makes little sense to feed something that is more likely to create a allergic reaction than something that isn’t.

Dr. Jean Hofve wisely advises against feeding fish and suggests that it be reserved as a very occasional and special treat–certainly no more than once a week.

If you’re really anxious to give your cat a treat once in awhile, go for something like small bits of dehydrated chicken liver or freeze-dried chicken hearts. But skip the fish. Feed something with fur or feathers, not fins. It’s kinder to–and safer for–your carnivore.

Parade passes by (an opportunity)

“These meals may also have contaminants and food-borne bacteria or toxins.”

This comes from an article that appeared in this weekend’s Parade magazine by a veterinarian titled, “The Right Food for Your Pet.”

For a brief moment when I first scanned the article, my heart skipped a beat. How terrific, I thought, that an article by a veterinarian in a mainstream, widely read publication was drawing attention to the problem with so many commercial pet foods and the contaminants and toxins found far too often in them.

That’s what I get for scanning an article before I permit my heart to leap. No, sadly, the author was instead referring to the ostensible disadvantages and dangers of homemade pet food in a pretty unfortunate article ostensibly designed to dole out sound advice on what to feed “Fido and Fluffy.”

Say what? With all the pet food recalls over the years for aflatoxin–never mind the latest appalling situation with the record recall this year–we’re being warned off of making our own food? Isn’t it about time to teach us how to do it safely?

“Cooking for a pet requires knowledge beyond boiling chicken and rice.” Well, um, yeah, but not much more knowledge. Come on. This isn’t rocket science. Reverse engineer a mouse and serve it. Lots of people have been doing it with great success for a long time. During that same long time, tens of thousands of cats and dogs have succumbed to needless diseases from eating steady diets of inferior commercial food.

What a shame that the author didn’t use her bully pulpit to speak out on the folly of feeding dry food to cats and dogs. The article begins with an admonition to steer clear of homemade diets (“Stick With Store-Bought” reads the subheading) and then goes on to “weigh” the pros and cons of wet vs. dry. Dry food’s advantages are explained: it’s economical, convenient, and requires no refrigeration. The only thing going against it, apparently, is that it has “less palatability.”

No mention of the overwhelming evidence that dry food contributes to inflammatory bowel disease, urinary tract disorders, diabetes, and obesity. None.

  • Dry food is a completely upside-down diet for a cat. A cat needs high (animal-based) protein, low or no carbohydrate, and plenty of moisture. Dry food is low in animal-based protein, extraordinarily high in carbohydrates, and is moisture-depleted.

The other warning about making homemade food — “few have been tested for performance over long periods of time.” Really? As opposed to the obscenely short (and often inhumane) feeding trials that allow a manufacturer to slap an AAFCO label on a can or bag and imply that the food is nutritionally complete? If you dig around on my website, you’ll find that I take no comfort in AAFCO. (That’s the Association of American Feed Control Officials).

It’s important to understand what AAFCO is and what it isn’t. A pet food can carry the AAFCO claim if it, or a member of its related family of products, has been tested on a small population of animals for six months and has been shown to provide adequate nutrition. We ought not to confuse this with the notion that it means the food is truly health-building and health-sustaining for life. If a can or bag is labeled as meeting AAFCO standards, all that means is that animals don’t DIE when fed only that food for six months and don’t lose more than 15 percent of body weight. So as long as the animal is alive, hasn’t lost 15 percent of their body weight, and a minimal blood test reveals that a handful of values are in an acceptable range, the food gets the AAFCO seal. Moreover, only eight animals need to participate in the feeding trial, and only six need to complete the 26-week trial.

The diet being tested fails if any animal shows clinical or pathological signs of nutritional deficiency or excess. Specific minimum values for the blood tests are given, and applied to the average result of all participating animals that finished the trial.

Remember, the rules for AAFCO are that if one particular product in a manufacturer’s line was tested and found to meet the AAFCO standard, the company can include this same statement on other products in the same family. So when you see an AAFCO statement on a pet food label, you have no way of knowing if that specific product was actually tested in a food trial. Moreover, the AAFCO protocols include blood tests that screen only four different blood values at the beginning and end of the food trial: RBC, hemoglobin, packed cell volume, and serum albumin. Even the basic veterinary blood profile screens for at least 25 values.

So please, Parade, don’t worry that the homemade diet that I serve and that tens of thousands of others serve “hasn’t been tested for performance for long periods of time” by the pet food companies or AAFCO.

Mother Nature did that for us.