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Old June 17th, 2008, 10:33 PM
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Originally Posted by dogmelissa View Post
Define "too high in carbs".... Cats don't *need* carbs, but they can use them.
"Too high in carbs" is anything more than what cats have evolved eating over millions of years, and what they are physiologically able to handle over the course of their lifetime. Let's look at their typical prey, say a mouse, which comes in at less than 5% carbs, about 40% protein and roughly 50% fat, give or take. A diet of 38% carbs, day in and day out, is a far cry from 5%. And just because a cat can use carbs, doesn't mean they should. From Dr. Zoran’s well respected abstract on the subject:
“Cats also have several physiologic adaptations that reflect their expected low CHO (carbohydrate) intake. The first of these is that cats lack salivary amylase, the enzyme responsible for initiating CHO digestion.25 In addition, cats also have low activities of intestinal and pancreatic amylase and reduced activities of intestinal disaccharidases that break down CHOs in the small intestines.25,26 These specific differences do not mean cats cannot use starch. In fact, cats are extremely efficient in their use of simple sugars. However, it does underscore their development as carnivores and the expected low amounts of grain in their typical diet. These digestive differences may mean that high amounts of CHO in diets may have untoward effects on cats. For example, high amounts of CHO in diets decrease protein digestibility in cats because of a combination of factors, including increased passage rate.”
“In cats, the liver also has several distinct features that influence disaccharide metabolism. In most animals, hepatic hexokinase (a constitutive enzyme) and glucokinase (an inducible enzyme) are active and responsible for phosphorylation of glucose for storage or oxidation. Cats differ in that they have minimal function of hepatic glucokinase, and the activity is not adaptive (ie, activity cannot be up-regulated when the diet contains large amounts of CHO).28,29 In addition, cats also have minimal activity of hepatic glycogen synthetase (the enzyme responsible for converting glucose to glycogen for storage in the liver).2 Again, the likely reason for low hepatic glucokinase and glycogen synthetase activity in cats is a metabolic program that uses gluconeogenic amino acids and fat, rather than starch, in their diet for energy. As a result, cats have limited ability to rapidly minimize hyperglycemia from a large dietary glucose load.”
“The liver in cats also does not contain fructokinase, an enzyme necessary for metabolism of simple sugars. Lack of this enzyme was documented in a study30 in which cats that consumed diets high in simple sugars became hyperglycemic and fructosuric.”

Originally Posted by dogmelissa View Post
I'm pretty sure that unless I feed a homemade or raw diet, there's going to be a significant percentage of carbs in the food I feed to my cats.
Unless you were to feed canned.

Originally Posted by dogmelissa View Post
- carbs are bad for diabetic cats.
Not only that, they frequently contribute to a cat becoming diabetic in the first place.

Originally Posted by dogmelissa View Post
not to mention that in comparing these two foods, they don't even list the same nutritional components, so I am comparing apples to oranges.
Which is why I use the charts on this website as reference, since they use the “as fed” information provided by the manufacturers, calculated as a percentage of calories. Much easier to compare.
Originally Posted by dogmelissa View Post
I have yet to find any real information backing up your claim that carbs cause alkaline urine,
Let me specify that grains increase alkalinity. It’s also well known that meat protein increases urine acidity, which, along with urine dilution, are the important considerations in cats with struvite crystals.

Here’s another tidbit:
“CONCLUSIONS AND CLINICAL RELEVANCE: Starch and fiber in diets potentially stimulate formation of struvite crystals. Hence, reducing dietary carbohydrate is desirable to prevent struvite urolith formation.”
Originally Posted by dogmelissa View Post
and in fact I found a source that says that a treatment for cats with crystals is actually a LOW-protein food (Veterinary advice from John Burns BVMS MRCVS).
Sorry, I can’t take anyone seriously (vet or not) that’s selling a dry cat food with the following ingredients:
“CHICKEN & BROWN RICE_- Contains: Brown Rice, Poultry Meat Meal, Maize, Poultry Fat, Chicken Liver, Seaweed, Vitamins and Minerals”
“OCEAN FISH __Contains: Brown Rice, Fish Meal, Maize,Fish Oil, Chicken Liver, Seaweed, Vitamins and Minerals”
And his comments about cats and carbohydrates are in complete contradiction to what other highly respected vets (like Dr. Zoran, Dr. Elizabeth Hodgkins, Dr. Lisa Pierson, Dr. Jean Hofve) have to say on the matter. And none of them are selling cat food.

Originally Posted by dogmelissa View Post
That being said, the crystal "problem" is under control with the cranberry, which is a recommendation of my veterinarian.
That’s great, and I hope Taz remains problem-free. However, cranberry is mostly considered effective against bacterial infections, not necessarily against crystal formation, which is usually sterile in cats.

Either way, good luck with whatever food you decide on.
"To close your eyes will not ease another's pain." ~ Chinese Proverb

“We must not refuse to see with our eyes what they must endure with their bodies.” ~ Gretchen Wyler
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