Is commercial pet food killing your pets?

is commercial pet food killing your pets

Regular readers will, I hope, excuse this interruption from my usual stuff on men’s health, because I thought this issue was important. Namely, that commercial pet food may be killing your pets. Give you one guess as to the reason.

Back when I interviewed Dr. Eugene Weinberg, he mentioned in passing, “Sadly, commercial pet food contains a serious excess quantity of iron.”

First I’d heard of this. Dr. Weinberg, who spent his scientific career on the biological effects of iron, knew this, but I can almost guarantee no one else does. In searching for this on the web, not much comes up.

Calorie restriction experiments using mice are seriously off due to iron in the food

Then, a little while ago I was reading an article called “Hepcidin and iron homeostasis” (a little light bedtime reading), and came across the following in a discussion of the iron requirements of lab mice:

Furthermore, standard mouse chow has high iron content (about 350 ppm [parts per million, or mg/kg] or about ten times the daily dietary requirement), and leads to significant iron loading even in healthy mice, potentially confounding studies of iron regulation.

Damn, laboratory mouse chow has ten times the daily requirement of iron! Is that even true? I set out to see.

Let’s take a look at the website of LabDiet, “the world leader in laboratory animal nutrition”. Their mouse diet (PDF) has 200 ppm iron. Mouse requirement for iron is estimated at about 35 ppm.

So this particular food for lab mice doesn’t have ten times the amount of iron, but a mere six times or so the amount.

Geez, what do you think that does to calorie restriction and other anti-aging experiments done on mice, where the control animals are allowed to eat as much food that’s loaded with toxic amounts of iron as they want? Makes these experiments garbage, that’s what.

Calorie-restricted animals aren’t just eating less food, they’re consuming far less iron. And we already know that one of the results of calorie restriction is that CR animals end up with far less iron in their bodies.

And they live longer too. How about that.

Maybe if they didn’t feed the control mice toxic levels of iron, they might live substantially longer too.

Pet food is loaded with toxic levels of iron

OK, but what about pets?

Here, information is a bit more difficult to find. An article from the Canadian Veterinary Journal estimates the iron requirement of both dogs and cats as about 80 mg/kg (same thing as 80 ppm).

The exact amount of iron in various pet foods is also hard to discover, but let’s look at LabDiet again. They have a feline diet, and it contains 290 ppm iron, or 3.625 times the estimated requirement of a cat for iron.

Do you think that might be killing cats before their time? I do.

Again, I couldn’t find a detailed analysis for any dog food, but Purina Dog Chow is fortified with ferrous sulfate, i.e. iron. Keep in mind that meat, a major ingredient of dog and cat food, already has lots of iron. Another brand, Blue Buffalo, is fortified with iron amino acid chelate.

Humans shouldn’t take iron supplements unless they have a demonstrated need. I’m not a veterinarian, but I suspect that must also be true for cats and dogs. There’s no physiological need. Yet, all cats and dogs seem to be eating iron supplemented food.

So, we don’t know how many times the requirement of iron dogs and cats typically get, except in the case of cats on the LabDiet, in which case it’s about 3.5 times the requirement. (More than 6 times for lab mice.) And presumably LabDiet is the company that takes the most care with the composition and analysis of the food, since scientists need to know what they’re giving their animals.

Puppies and kittens need plenty of iron to grow. Adult animals, not so much.

Longest-lived cats did not eat commercial cat food

Now, consider the case of the world’s longest living cat (so far as is known), Creme Puff. This cat lived to be 38 years old.

When I first read about Creme Puff, I figured that she was either some kind of genetic fluke, or other flukiness of some kind intervened to make her live long.

But then I found out that Creme Puff’s owner also owned another cat, unrelated to Creme Puff, named Granpa, who lived to be 34.

Not looking like such a fluke now.

Then I found out that the owner of Creme Puff and Granpa did not feed them commercial cat food. He fed them “among other things, bacon and eggs, asparagus, broccoli, and coffee with heavy cream”. And they lived more than twice as long as the typical cat.

I’m going to take a guess here that these cats lived so long because their owner didn’t feed them toxic levels of iron.

Is commercial pet food killing your pets?

The story isn’t totally complete, since we don’t know how much iron is in most commercial food (though I bet it’s a lot), how much iron cats and dogs typically accumulate over a lifetime, nor what the real average lifespan of a cat or dog is. If they’re all being fed toxic levels of iron, then they’re all dying before their time, and we have no clue as to their real natural lifespan.

Well, we have one clue, the lifespans of Creme Puff and Granpa. Maybe all cats (and dogs) are dying well before they need to.

All of this and much more is discussed in my new book, Dumping Iron.


Leave a Comment:

José Carlos says December 23, 2015

Sigh. The problem is not only pet-related, I’m afraid. Even the cattle, the fowl, and the farmed fish is being given the wrong food.

Shaq says December 24, 2015

For what it’s worth, I contacted Blue Buffalo (turns out we buy their grain-free/low carb canned food for our cat…). Their response: “Unfortunately, I do not have the Iron content for any of our pet formulas.”

Also, I took a look at the Greenies cat treats we buy. They have 120mg/kg of iron. Time for a different product.

Seems like there’s a business opportunity here for a pet food supplier.

    P. D. Mangan says December 24, 2015

    That’s interesting, Shaq, thanks for reporting on it. The Greenies may not be too terrible if the cat requirement is 80 mg/kg, only 1.5 times the amount, though of course one would want to do better. Blue Buffalo probably has the iron analysis tucked away in a safe somewhere with only the CEO having access.

Three supplements you should avoid - Rogue Health and Fitness says January 31, 2016

[…] And don’t let your pets take them either. […]

Shawn R says February 25, 2016

Raw food (biologically appropriate) is almost certainly best for pets. You would think that carnivores absorb huge amounts of heme iron from eating raw animals (as cooking transforms some heme into non-heme), but it’s actually not the case if humans are any indication:

Heme iron is easily absorbed, but only up to a point. Even if you drink lots of raw iron-rich blood the body will only absorb a maximum of ~2mg of heme iron in one meal. However, meat is known to increase non-heme absorption and cooking transforms a portion of heme into non-heme. Thus, cooking meat should increase the amount of iron you absorb—and the meat itself will promote iron absorption from other iron-rich foods.

Feasting on only raw whole animals and blood, like your dog does, does not likely promote iron overload thanks to the heme ceiling. This is likely part of what protects carnivores and carnivorous cultures from iron overload (some cultures were actually shown to be anemic in studies).

Few people realize that cooking meat destroys the porphyrin ring around heme iron (porphyrin is an antimicrobial that appears to prevents pathogens in the gut from blooming on the raw iron). However, the destruction of the porphyrin ring from heat means that eating a lot of cooked steak should allow pathogens to feast on the iron in your gut, which is believed to be associated with colon cancer as the flora is believed to be involved.

But they key here is that meat greatly increases the absorption of non-heme iron and there is no limit to the amount of non-heme iron you can absorb in one meal (see the study in the first link as a reference). The good news is that eating plants without meat and without vitamin C will result in very poor iron absorption. So, while the iron absorption of whole grains is relatively poor (thanks to the phytates) meat or vitamin C will promote iron absorption (not necessarily a bad thing if you don’t have enough iron). Think beans and salsa.

The Low Testosterone and Obesity Vicious Cycle - Rogue Health and Fitness says August 10, 2016

[…] The secular decline could be caused by environmental chemicals — endocrine disruptors. Just yesterday, a report was published that found that sperm quality in dogs has declined, fewer male dogs were born, and phthalates and PCBs, i.e. endocrine disruptors, were found both in the dogs and in their commercial food.1 (Another good reason not to feed your pets commercial pet food.) […]

Susan Coe says September 5, 2016

Thank you for this article! My 7yo cat has been on a commercially prepared freeze-dried raw diet for most of her life, and has just been diagnosed with IBD. In checking her food, I saw that it contains iron supplementation, and it was the first thing I changed after her diagnosis. I will never again feed her food with supplemented iron. Nobody in the raw pet community is taking about this, but I think it is of the utmost importance, and will share your article in those groups.

    P. D. Mangan says September 5, 2016

    Thank you Susan. I’m dimly aware of the group of people that advocate raw food for pets; seems weird that some of it would have added iron. Gut disorders like IBD can definitely be caused by excess iron – see this post on wheat grass and ulcerative colitis for more. Have you seen any changes in your cat since the change, or is it too soon to tell?

    I have a 1.5 year old cat, and he gets nothing but meat, usually raw.

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