In my spare time, I often research feline nutrition – yes, I’m THAT much of a super geeky crazy cat lady.
Every so often, I run into an item of information that doesn’t make sense to me. What I love about what I understand about feline nutrition is it makes sense – it’s logical! An obligate (true) carnivore, evolved from a desert species, needs meat and moisture. Even my simplistic mind can get a grip on that! As my nutritional heroes say – this isn’t rocket science!
So, it bugged me when I discovered taurine requirements were lower for dry food than wet food. Why? WHY?
For those that don’t read articles on pet food in their spare time – taurine is an amino acid. (An amino acid is a component of protein.) Most species (including humans and dogs) can manufacture enough taurine on their own, so it’s not an essential amino acid for them. Not cats, one of the facts distinguishing them as true obligate (strict) carnivores rather than an opportunistic carnivore (meaning they’ll eat meat if they can get it – but they can also survive, even thrive, on plant proteins.)
Interesting little sidenote – when cat food was first created, it was basically dog food – made into smaller cans or smaller kibble pieces. In the 1980’s a researcher was studying heart disease in cats when he found that nearly all his patients were deficient in taurine levels. When he supplemented taurine, they improved. Thus, pet food manufacturers began supplementing cat foods with taurine. Turns out taurine, which naturally occurs in raw meat, is easily destroyed by cooking. It also oxidizes quickly once meat is ground – and may be degraded by freezing.
So, back to my ponderable. Why is less taurine needed if cats are on a dry diet? WHY?
Well, in doing some other research – I found a great recent study on carbohydrate malabsorption. The study found that carbohydrate malabsorption was a common feature in IBD (inflammatory bowel disease) in felines. That didn’t surprise me in the least. In my experience (with five cats with IBD so far – either adopted or fostered), foods containing high levels of carbohydrate (such as dry food) were not tolerated well at all. Again, cats are obligate carnivores – they’re not designed to eat carbohydrates, they’re designed to eat protein and fat. They have absolutely no nutritional requirement for ANY carbohydrate.
Then, reading another study, one of the items they noted was that cats on antibiotics required less taurine than cats that weren’t on antibiotics. Through some research, they concluded that taurine was in some way utilized by the healthy gastro-intestinal (GI) bacteria. Antibiotics, as we know, kill off not only unhealthy bacteria, but healthy ones as well. So, by having less GI bacteria, the cats needed less taurine.
LIGHT BULB MOMENT: So… if carbohydrates may affect GI bacteria (as indicated by malabsorption), and dry foods are naturally higher in carbohydrates (as a starch is required to process those little kibbles), and GI bacteria utilize more taurine – then it makes sense that less taurine is needed in dry foods because dry foods are probably damaging the healthy GI bacteria that would otherwise utilize the taurine!
YAY! I think I get it! Or, at least I have a theory – and I’m always happier having a theory, even if it may ultimately be proved incorrect – than I am just being clueless.
Life of the Lintee Bean 
Lynette,
I appreciate your reasoning.
Have you found any research that indicates the healthy versus IDB gut-flora levels? And along the same lines- are the dry ingredients promoting the growth of unwanted flora?
G
Glenn,
I haven’t found research on healthy versus IBD flora levels specifically. There is some references, such as in Dr. Zoran’s article:
Click to access zorans_article.pdf
This may be sad – but I can actually type out that link from memory.
Quotes (sadly, have to type it out as I can’t copy & paste from the pdf):
“Direct supportive evidence for a specific role of bacteria in the development of IBD in cats is lacking, but several aspects of digestive physiologic and intestinal microbiologic characteristics of cats suggest a possible role for bacteria in the disease.”
“…diets higher in CHO or fiber may influence bacterial numbers or species, altering bacterial flora in ways that may include overgrowth of nonbeneficial or pathogenic species. To the author’s knowledge, there have not been any studies to evaluate the effects of moderate- to high-CHO maintenance diet, compared with effects for a high-protein, low-CHO diet, on the numbers or species of enteric microflora in cats. Nevertheless, because the natural diet of cats is a high-protein, moderate-fat, low-CHO diet, it seems reasonable to assume the enteric flora and anatomy of the gastrointestinal tract of cats would be designed to accommodate these diets more readily.”
Lynette
When you opne the pdf, click on the “select” tool. Then you can highlight, copy and paste. 😉
*open
OOPS!
Love the “select” tool. Unfortunately, it doesn’t work on Zoran’s article – at least not for me!
By the way – no worries on the oops! Oh my gosh, yesterday I found where I’d written “concurred” instead of “conquered”! :I
Lynette-
Tannetje’s book references the importance of not feeding sterile (i.e. dry) food to cats because they need the bacteria like we do.
Vindication (smug grin)
Hi Eddie,
I’ll admit I wasn’t going to approve your comment, as my blog is my “happy place” and I generally feel if you want to spew venom at me, you can do it on your own blog. I have no obligation to enable you to do it here. But, Glenn made me feel a bit guilty about censoring (other than all the spam, which I’ll continue to let fill the trash bin)… so here you are.
I doubt anything I’ll write will change your opinion at all, but for the benefit of anyone else that stumbles across my little blog, here’s some of my “science” (and it’s not on a pet food manufacturer’s site). If you’d clicked on some of the links in my original entry, you’d have seen some of them:
“The single most positive aspect of the whole rabbit diet was the stool quality. Cats fed the raw rabbit diet consistently had extremely firm, non-odorous and well formed stools. By comparison, cats fed the commercial cat food never had stools as well formed, and usually had stools ranging from unformed to soft-formed.”
“Furthermore, studies like this suggest that there is still much to be learned about the comparative effects of commercial diets and natural foods on stool quality and general well being. It is clear that the ideal commercial feline diet has yet to be developed for maintaining optimal intestinal health.”
Role of Diet in the Health of the Feline Intestinal Tract and in Inflammatory Bowel Disease
“Rice has often been recommended as a good carbohydrate source for cats with gastrointestinal problems because of presumed good digestibility (26). Rice has also been reported to have antisecretory properties (27); however, all other carbohydrates tested in this study produced similar breath-hydrogen AUC values to rice. The differences in breath-hydrogen AUC cannot be directly equated to the grams of starch malabsorbed because of possible differences in the amount of hydrogen produced per gram of carbohydrate from different sources (28).”
“Cats with gastrointestinal disease show broad-spectrum subclinical carbohydrate malabsorption but no untoward effects in this situation demonstrating remarkable carbohydrate gastrointestinal tolerance. Fecal grade does not seem to be a reliable measure of dietary carbohydrate malabsorption in cats. Additional investigations into the responses to different carbohydrates by cats with gastrointestinal disease are needed.”
Carbohydrate Malabsorption Is a Feature of Feline Inflammatory Bowel Disease
I’m running short of time here, so I’m not going to quote Dr. Zoran’s article, but I provided a link earlier:
The Carnivore Connection to Nutrition in Cats by Dr. Debra Zoran, DVM, PhD, DACVIM; Journal of the American Veterinary Medical Association (JAVMA 12/1/02)
There are more, but I’ll stop there…
Let’s look at one of the studies you included shall we?
“The highest (P < .05) digestibilities of DM and OM occurred when cats consumed the diet with no supplemental fiber, and the lowest (P < .05) digestibilities occurred when cats consumed the SCFA blend (S C) diet.digestibility and resulted in poor stool characteristics. ”
So, digestibility was highest when there was NO supplemental fiber. (Yes, I understand the difference between carbohydrates and grains.)
“To summarize, four modes of action for decreased nutrient digestibility of the SC diet are plausible: 1) rapidly fermentable fibers (citrus pectin and carob bean gum) promoted bacterial overgrowth in cats consuming the SC diet, thus causing interference in the action of bile acids, 2) bacterial overgrowth in cats consuming the SC diet caused decreased intestinal pH, thus decreasing the activity of pancreatic en- zymes, 3) citrus pectin, the fiber of highest concentra- tion in the SC diet, may have reduced the activity of several pancreatic enzymes, and 4) fibers in the SC diet may have decreased nutrient absorption as a result of their viscous nature. A combination of these effects also may explain the low nutrient digestibili- ties that occurred for cats consuming the SC diet. Undesirable fecal characteristics resulted because of the low nutrient digestibilities.as TDF in fecal samples. The SF and SB diets, which contained little fermentable fiber, also had low TDF digestibilities. This observation corroborates results of a previous experiment using dogs fed diets containing similar types of fiber (Sunvold et al., 1995). Wet fecal output was greatest by cats consuming the SC diet (Table 71, which reflects the poor nutrient digestibili- ties of this diet. The low TDF content of the NF diet was probably responsible for the low wet fecal output by cats fed this diet. Wet fecal output also was expressed per gram of TDF ingested (Table 71, providing a more appropriate index of the effects of different fiber sources on wet fecal output. The high wet fecal output per gram of TDF for cats consuming the NF diet reflects the low amount of TDF ingested. Cats consuming the SC diet ”
I fail to see how identifying some fiber sources as “less bad” makes them desirable.
As for the credentials of those I look to for input – well, Dr. Hodgkins spent 20 years working at Hill’s then went on to research, develop, and patent the first low-carbohydrate diet for cats with diabetes (Purina DM canned). Her book, “Simple New Secrets to a Longer Stronger Life” is fantastic. Does she make money off telling people to feed canned food? Only if they buy Purina DM canned, in which case she makes less than a dollar per case. Yet, she doesn’t generally recommend the canned food she profits from, she recommends readily-available canned foods and raw.
Does Eukanuba profit if you follow the advice published on their site?
Dr. Zoran holds a PhD in Animal Nutrition. I also look at other published articles and studies and exercise my critical thinking skills to glean what I can from them.
Eddie, it might be a good idea if you could back up what you say using sources that aren’t funded/connected with the pet food industry (Eukanuba/Iams). Credibility is lost when you don’t use unbiased references.
Eddie- I can also quote loads of commercial sites pushing their own products as the ideal solution for your cat, your car, your wrinkles or the flab around your belly. However, advertising & comforting messages designed to push products is not science. There is a growing awareness in Europe as well that advocates this approach to domesticated feline diets. It is not a few crackpots referencing each other to make a quick buck as you insinuate; it is a growing awareness of carers and owners of the obesity, IBD, diabetes and skin allergy that makes people question the blind faith that they have had before, whether in science, marketing or governments. This is not unique: products assumed to be safe and beneficial have proven to not be so. We have had it with BSE, thalidomide and DDT. We now face it with avelox and you are obviously lower down the curve than we are when it comes to proper feline nutrition. But don’t worry, you’ll get there one day. Please just don’t feed any cats until then.
The more I look at “Eddie’s” links, the more I like them, I must say.
Eddie had linked to:
http://www.eukanuba-scienceonline.com/download/slibrary/Feline%20WSAVA%202000.pdf
which has summaries of the 2000 WSAVA (World Small Animal Veterinary Association) congress feline sessions. (I prefer to link to directly to the Congress, rather than a pet food company’s site.)
Diagnosis and Medical Treatment of Non-Obstructive Feline Lower Urinary Tract Disease
Dennis J. Chew, DVM, DACVIM; CAT Tony Buffington, DVM, PhD, DACVN
Quote from this FLUTD session:
“Consumption of a canned, magnesium restricted,
urine acidifying, salt-supplemented diet
dissolved naturally occurring struvite calculi over several
weeks in cats.”
Hmm… no mention of *dry* helping dissolve crystals, just canned/wet food.
Another quote from this urinary tract session:
“Cats suffering idiopathic cystitis seem to
benefit from provision of a single, canned diet, if such a
feeding plan is not too stressful to the cat or the owner.”
Again, a canned diet benefits another urinary tract disorder – is it a huge leap to wonder if moisture-deprived dry diets could be *creating* these urinary tract issues in the first place?
I see there was another session on urinary tract disorders (which seem very prevalent… could that be because so many feed dry food?)
The Role of Diet in Managing Feline Lower Urinary Tract Diseases
Mark A. Tetrick, DVM, PhD
Quotes:
“Feeding of canned wet foods may also help to increase
water intake and reduce urine specific gravity”
“Dietary management with a wet or canned acidifying
diet may provide benefit in reducing the recurrence of
idiopathic cystitis. Although the mechanism of a
reduction in recurrence is not known, it may be related to
greater water intake with the feeding of a canned diet and
the resulting reduction in the concentration of the urine
and reduction in the concentration of potentially irritating
substances in the urine.”
There were some sessions on management of diabetes as well, including:
An Overview of Feline Diabetes Mellitus
Claudia E. Reusch, Dr. med. Vet., PhD, DECVIM
Quote:
“It is important to realize that fructosamine does not reflect the glycemic situation in individuals with hypo- or hyperproteinemia or hyperthyroidism and therefore,
should not be used in those individuals.”
“The goal of the self-monitoring is that owner can perform glucose curves at home in a stress-free environment, thus avoiding typical stress-related problems of blood glucose measurement in the clinic. Preliminary data show that most cat
owners are able to reliably perform blood glucose curves
at home and that self monitoring is a new and important
tool in the management of diabetic animals.”
(Unrelated to diet, but supports my use of home-testing rather than fructosamine tests.)
With that, I had better get home! I do have one cat (I adopted in November 2006) that is still on insulin (as opposed to the three former diabetics currently in my home that are not), and his blood sugar was normal this morning, so he got no insulin – but I’m not sure his pancreas is yet ready to go another 12 hours without it, so he may be in need of a shot now.
Hi Lynette,
This is all very helpful; thank you for your informational postings!
I wanted to add a personal account of my experience with dry/wet/raw foods and my cats. We initially fed our kittens some dry and wet canned food and then switched to raw, hoping to eliminate some health issues. For the time (about 6 months) that I fed my two cats raw food exclusively (Aunt Jeni’s rabbit), I noticed that their litterbox had the *aroma* of garden soil rather than its previous, much less pleasant smell. For digestibility, raw food seems to be a remarkable food for cats. Nevertheless, the cats had (severe) dental issues that prevented us from continuing with the raw food (the bones seemed to exacerbate the condition) and so when out vet recommended wet canned, we went for it.
This seems to be a good medium, though I like the idea of adding in some raw food (sans bones) to supplement now and then. Another cat we’ve adopted really(!) liked kibble, so we started giving her a little bit with the wet canned food, but on noticing her digestion became less healthy: more hairballs, coughing/wheezing, and less robust litterbox deposits, we decided to just stay with the wet canned.
I look forward to browsing more on your site(s). Thanks again.
Hi Kim!
I think your raw meat supplements will do a lot to maintain dental health. While I don’t believe kibble (dry food) does much to help the teeth, I do believe biting into raw (or to a lesser extent, cooked) meat will help remove plaque from the teeth and exercise the gums. For that reason, I add chunks or meat (such as chicken hearts) to my ground raw food.
While I firmly advocate a wet diet (over a dry one), I do realize that an entirely ground diet provides no chewing action. However, if that chewing action was provided by dry food (or not outweighed by the large amount of carbohydrates in kibble), I don’t think we’d see the over 60% of cats with dental disease by age 3 that we do!
I hope you will visit again – and comment with more of your experience. Thanks!
[…] online forum for diabetic caregivers recently. L-Carnitine is grouped among the amino acids (like Taurine), and is also known as Vitamin Bt. I’d known of the link of carnitine to weight loss and the […]
[…] I cringe when I hear people say they don’t think adding supplements are necessary, and I gasp when I hear people that just feed their cats cooked meat. That most CERTAINLY does not contain sufficient minerals like calcium, zinc, etc. they would get from the bone. Also, since it’s cooked it is DEFINITELY deficient in taurine. Taurine oxidizes quickly on grinding, it is destroyed by heat (cooking), and it may be lost in storage/freezing. Canned and dry commercial cat foods must be supplemented with taurine as well! Now, rabbit (as used in the Winn study) is lower in the amino acid taurine than some other meat sources (like turkey) but personally, I would NEVER take the risk of feeding my cats a diet that wasn’t supplemented with taurine. Taurine may be supplemented as a powder or as added raw hearts – I actually usually add both. The hearts give my cats some chewing action, good for dental health. More on taurine here. […]