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.
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.
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.
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.
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.