Category: Raw feeding

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Using Nutritional Yeast in Feline Renal Failure Diets

I stopped feeding nutritional yeast a while back, because I was feeding quite a bit of canned food and quite a bit of liver. However, given that liver contains a higher phosphorus-to-B-vitamin ratio, and given the fact that I’m feeding my cats canned food maybe once every ten days now, I’m feeding about twice the nutritional yeast than I normally would, i.e., almost two teaspoons per cat per day.

Several reasons why I’m doing this:

1. Eric’s peeing a whole lot, which means he’s losing a lot of water-soluble vitamins, like B vitamins. Nutritional yeast contains a LOT of B vitamins. Here’s a some relevant information (lifted from Bulkfoods.com); quantities are per heaping tablespoonful, which is close to what I feed total for both cats every day:

Thiamin (B1): 9.6 mg
Riboflavin (B2): 9.6 mg
Niacin: 56 mg
Vitamin B6: 9.6 mg
Folic Acid: 240 mcg
Vitamin B12: 8 mcg
Biotin: 20.8 mcg
Pantothenic Acid: 1.04 mg
Phosphorus: 174.4 mg
Calcium: 11.2 mg

I initially wanted to find a meat-based food source of B vitamins, and what popped to mind immediate was chicken liver. But chicken liver can’t even come close. Here’s the B-vitamin profile for two ounces of liver (approximate 7 grams)—again, I’m approximating how much I’d feed to both cats per day:

Calcium: 5 mg
Phosphorus: 169 mg
Thiamin: 0.174 mg
Riboflavin: 1.013 mg
Niacin: 5.545 mg
Pantothenic acid: 3.553 mg
Vitamin B-6: 0.486 mg
Folate, total: 335 mcg
Folic acid: 0 mcg
Folate, food: 335 mcg
Choline, total: 110.8 mg
Vitamin B-12: 9.45 mcg

So about the same amount of phosphorus between the nutritional yeast and the liver, but except for B-12, folate and pantothenic acid, the nutritional yeast gives more B-complex bang for the buck (and it’s a pretty close match for the B-12). The USDA National Nutrient Database doesn’t give the value for biotin in liver, so I don’t know how that compares in chicken liver vs. nutritional yeast, but I’m feeding egg yolks on a regular basis, so I know the cats are getting plenty of biotin no matter what.

2. Wow. That was a really long point. This second one is much shorter, I promise, and it boils down to this: Both cats really love the taste, but Eric loves it. And I mean, he really, really loves it. More than a fat kid loves cake. And given his depressed appetite, I’m perfectly happy to indulge him in this for as long as he’s around, and as long as it keeps him happy and eating.

3. Again, because of the increased peeing, Eric’s losing more potassium than he should. A heaping tablespoonful of yeast contains 320 mg of potassium and 5.2 mg of sodium. (Chicken liver is pretty good, too, but not quite as good; two ounces contains 131 mg of potassium and 40 mg of sodium.) That’s pretty much perfect: lots of potassium to make up for what he’s losing, and relatively little salt, because cats with chronic kidney disease often have difficulty eliminating sodium, which can sometimes result in high blood pressure.

4. Eric’s phosphorus and calcium levels are normal. I wouldn’t feed this to a cat with elevated phosphorus, or at least, I wouldn’t feed it without a phosphorus binder. I’d go with a B-complex vitamin supplement instead. But I want to keep his nutritional supplementation as food-based as possible for now. Note that this choice is a decision based more on philosophy than science, driven largely by my opinion that food will provide better nutrition than, well, bare, isolated nutrients.

To feed, or not to feed? That is the question.
Whether ’tis nobler to suffer the slings and arrows of yeasty misfortune… OK. Right. Sorry about that. At any rate, I’ve heard people express concern about feeding nutritional yeast as a dietary staple, but I have yet to read an explanation that makes sense to me. It’s definitely high in phosphorus, but you can compensate for that in a home-made diet by ensuring you’re providing enough calcium.  There’s some talk about how it’s a cheap by-product of beer brewing, but that’s brewer’s yeast. From what I understand, they’re the same species (Saccharomyces cerevisiae), but nutritional yeast is grown and killed solely as a nutritional supplement and isn’t used for brewing first. (I’ve read conflicting information on this, and will be more than happy to be corrected.)

I’ve read other people expressing concerns about it “fermenting” in the stomach (Feline Future used to claim this, but seems to have backed off since then), which: what? First of all, it’s completely deactivated, which means it’s dead—it can’t reproduce and actually, y’know, ferment. Now, if we’re talking about live yeast, like baker’s yeast or active brewer’s yeast, that would be a different matter entirely; I knew somebody whose dog stole and ate two batches of raw bread dough (labradors, man) and had to be taken to the ER because the bread started expanding in his stomach. So if there’s going to be any fermentation, that means microorganisms acting on the dead yeast as a substrate.

Now, nutritional yeast is pretty high-protein (about 50% of it consists of protein dry weight), and over half of its carbohydrate content is fiber. Protein, as far as I know, generally isn’t fermented; most fermentation tends to happen with carbohydrates. But the amount of digestible carbohydrate in  nutritional yeast is pretty marginal (3.3 g per heaping tablespoon) and the fiber may or may not be fermentable. If the fiber is fermentable, it’ll probably be fermented by bacteria in the colon, not in the stomach because feline stomachs are relatively sterile environments. But fermentation in the colon isn’t necessarily a bad thing—in fact, depending on the degree of fermentability, it could actually be a good thing. (Note to self: find out whether the fiber in nutritional yeast is soluble/insoluble, fermentable/non-fermentable).

However, if somebody has heard any sort of warning about nutritional yeast that’s backed up by something that makes scientific sense, I’m all ears. For now, my Google-fu hasn’t really turned up anything I need to watch out for.

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Why we hesitate to cook

Or not-cook, as the case may be for those of us feeding raw food.

(Note: I’ve written a companion piece on my worries about feeding commercial raw food, and why I’m taking the risk.)

Ladies and gentlemen, I submit that over the past forty to fifty years, we’ve been cowed and browbeaten by food advertising. Food companies tell us, over and over again, that cooking is difficult, messy and far too time-consuming for people with busy modern lives. They sell us microwaveable dinners, energy bars, cake mixes and canned spaghetti, all on the premise that they will be delicious, convenient, and (depending on the kind of instant food you get) healthy and nutritious.

Some foods claim to be meal replacements, like energy bars and Slim-Fast shakes, but not one of them has the chutzpah to claim that they should constitute your entire food intake. The foundation for a lot of the food advertising is that home-made is best, but cooking is arcane, difficult. Who has the time and skills to cook these days? And some of you need to eat our food or you’ll get fat (and then who will love you any more?). So use our products, of varying levels of crappiness, to suit your time and energy limits.

But home-made doesn’t have to be difficult or time-consuming. It’s perfectly possible to create a fresh, home-made meal in 25 or so minutes, and the only know-how you need is enough reading ability to follow recipe directions. Steaming vegetables doesn’t take all that long; neither does sauteeing chunks of meat, or drizzling raw salad greens with olive oil and vinegar. People, it’s OK. You have nothing to fear but fear itself—well, that, and accidentally burning your food, but this is where things like digital timers come in handy. What you make will almost assuredly taste better and be much more nutritious than what you can pour out of a box, a jar or a can. (Unless you burn your food. Seriously: timers are your friend. Also, instant-read thermometers.)

I don’t see how, in any way that matters, this is different from food for our pets. I’m not saying that everybody should make their own pet food, because bad home-made pet food is in many ways worse than bad commercial pet food. What I am saying that it’s a perfectly viable and relatively easy option, as long as you do your homework and approach it sensibly. Most people think otherwise, however, because the pet food industry has not only managed to sell us a convenience cobbled together from agricultural leavings, it has actually convinced us that feeding our cats anything else is going to be dangerous. Pet food companies have achieved what food advertising for humans hasn’t quite managed to do yet: they’ve made their food the gold standard against which everything else must be compared. It’s now conventional wisdom that commercial food should be fed as a sole ration to pets; anything else is unhealthy.

Pet food companies have managed to do this in a few ways:

Continue reading “Why we hesitate to cook”

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How to waste a perfectly good container of food:

Step 1: Grab a capsule of your boyfriend’s Omega 3 Essential Fatty Acid supplement and squirt it all over your cats’ food.

Step 2: Realize a moment later that it’s LIME-FLAVORED, and the food now smells like a weird combination of lamb, fish oil and citrus freshness.

Step 3: Try to feed to cats anyway.

Step 4:

failcheesecat.jpg

I gotta get the cats more salmon oil. One that’s not lime-flavored. (Seriously. Lime-flavored EFAs. What. The Fizznuck.)

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On Squash, Fermentable Fiber and Feline Kidney Disease

One of the squashes from our garden
One of the squashes from our garden

One of the things I did to modify Eric’s diet after finding out about his polycystic kidneys was to reintroduce squash into his diet. In the past several years, I had dropped feeding vegetables to my cats entirely, largely because I was feeding them whole ground animals and canned Wellness and Evo on the side. I figured that the canned food was providing plenty of vegetable matter. Now that Eric’s sick, however, I’m much more draconian about feeding mostly raw food—partly because it’s better for him, and partly because Eric prefers it over the canned, which is strange because in the past his sole food preference, near as I could tell, was HOORAY FOOD OM NOM NOM NOM.

I added the squash back into Eric’s diet largely because I remembered reading back in the day that squash helps trap nitrogenous waste that would otherwise make it into the bloodstream. Today I went on an article hunt to see whether this had any sort of scientific basis, or if it was one of those raw feeding myths that get passed around because it sounds so damn good.

Assessing the Evidence

Therapeutic use of fiber in chronic kidney disease (or, if you’re old-school, chronic renal failure) is much more well-studied in humans than it is in cats. There seems to be some evidence that the consumption of soluble/fermentable fiber leads to increased excretion of nitrogen via poopin’ vs. peein’, thus lowering the amount of nitrogenous waste circulating in the blood and therefore eliminated by the kidneys. But what about cats?

I’ve found one decently reliable study that specifically looks at cats. It’s by researchers at Iams, so it’s not exactly woo-woo; research from the Iams lab is about as mainstream as it gets. The researchers found that feeding moderately fermentable fiber (mostly beet pulp and fructo-oligosaccharides) to cats decreased serum nitrogenous waste and increased fecal nitrogen excretion. The study proposed the following hypothesis as to why this would happen:

The beneficial bacteria in the cat’s lower intestine feed on the moderately fermentable fiber, creating short-chain fatty acids (SCFAs) in the process. SCFAs not only do all sorts of nifty things, such as keep the intestine cells happy and healthy, they also increase blood flow. The increased blood flow to the intestine results in more urea being circulated to the intestines, and the bacteria, which also produce urease (an enzyme that denatures urea), convert the nitrogenous wastes to carbon dioxide and ammonia, which are then incorporated into the bacteria themselves and then pooped out by the cat, as opposed to circulating to the kidneys to be peed out.

This sounds really good and really plausible, and the results show pretty unequivocally that fermentable fiber helps reduce the urea load in the serum, which means less work for damaged kidneys, but keep these things in mind:

1. This study is really small, involving only sixteen cats.

2. They were fed the diets containing fermentable fiber for relatively short periods of time—two weeks total for with an active waste collection period of eight days.

3. The decreased waste could be due in part to the decrease in protein digestibility. The study noted that the protein digestibility decreased to 87-91% with the fermentable fiber blends.

4. As far as I could tell, they didn’t actually actually draw any blood and run blood panels; they looked at urine and feces only.

So the verdict right now is: it probably does help a little bit, but as with anything scientific, the people in the white coats need to study it more. Given that steamed squash doesn’t contain anything harmful to cats, and given the potential benefits vs. potential dangers (yes, there’s a decrease in protein digestibility from the fiber, but Eric’s getting so much high-quality protein in his food that I’m not worried about marginal decreases at this point), I decided to go ahead and give Eric a heaping tablespoonful of pureed squash per day, which comes to about 10-15% of his total food. I created a mix from a gem squash harvested straight from my garden and organic butternut from the store. He loves it. I don’t need to mix it in with the food; it’s a lurid orange dot amidst the raw rabbit and Nature’s Variety, and he often eats it first. I suppose we’ll find out whether it does anything when we test his blood again in January.

Fiber Content for Various Squash Species

If you’re curious about the fiber content of different species of squash, here’s the information I looked up on the USDA National Nutrient Database per 100 grams of raw squash (unless otherwise noted):

Butternut squash: 2.0 g  (86.41% water)
Acorn squash: 1.5 g (87.78% water)
Generic winter squash: 1.5 g (89.76% water)
Pumpkin: 0.5 g (91.6% water)
Canned pumpkin: 2.9 g (89.97% water)

Canned pumpkin has almost double the fiber content of raw butternut (on a dry matter basis) and six times more than raw pumpkin, which is interesting. It looks like you can get more bang for the buck by feeding canned pumpkin. Eric likes the fresh stuff much better, however, so I’m sticking with it for now.

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Thoughts on risk

(Note: This was originally posted to my Livejournal.)

An explanatory note: For those of you who don’t know already, I feed my cats mostly raw food—some of it home-made, some of it commercial—and supplement my forgetfulness and laziness with canned. (Canned is also good for trips out of town when the only available cat-sitters are squicked by feeding raw meat.) The bulk of their raw diet used to consist of ground rabbit (bones inclusive) supplemented with raw chicken liver; rabbit is far too low in fat and fat-soluble vitamins by itself to be a good, balanced diet for cats. I used to do another version, whereby I buy many pounds of whole meat and organs, cut them up so they’re about as big as my thumb, and then feed them to the cats with an accompanying calcium supplement (usually a commercial calcium carbonate supplement, but sometimes I’d use chicken necks rolled around in canned food). And then law school happened, and I gave up on the chunks o’ meat meals because they became far too time-intensive to prepare.

So! To get to my thoughts proper: Continue reading “Thoughts on risk”