Monday 27 July 2009

Cat Health and Diet

Some more thoughts on feline health from the brilliant Dr.Lisa A.Pierson, DVM http://www.catinfo.org and the connection between your cat's health and it's diet. Its a factor we ignore at our peril so please read on.

Common Feline Health Problems and Their Ties to Diet

There is a very strong and extremely logical connection between the way that we are currently feeding our obligate carnivores and many of the life-threatening diseases that afflict them.

  • Diabetes: Diabetes is a very serious – and difficult to manage – disease that is very common in cats. Why is it so common? The species-inappropriate high level of carbohydrates in dry food (and some canned foods) wreaks havoc on the blood sugar level of an obligate carnivore. The blood sugar level rises significantly upon ingestion of carbohydrates. With chronic hyperglycemia (high blood sugar) the insulin-producing cells in the pancreas down-regulate, or “burn out,” leading to diabetes.

Many cats have been successfully weaned off of insulin - or had the dosage significantly lowered - when transitioned to a low carbohydrate canned food. Please see this thread on the Feline Diabetes Board to read about many caregivers' success with their diabetic cats once all dry food was removed from the diet.

In addition to the issue of carbohydrates, dry food - because it is very calorie dense and is often free-fed - is the main reason why a very high percentage of cats are overweight or obese.

Fat cells produce a substance that makes the other cells in the body resistant to insulin. This promotes the diabetic state.

It is very important to understand the impact that a low carbohydrate diet has on the insulin needs of a diabetic cat.

If you have decided to start feeding your diabetic cat a low carbohydrate diet, please review my Feline Diabetes page first.

Please also be aware that many veterinarians underestimate the favorable impact that a low carbohydrate diet has on the insulin needs of the patient and they do not lower the insulin dose enough. If the insulin is not lowered accordingly, an overdose of insulin will occur which can be life- threatening. I strongly suggest that all caretakers of diabetic cats home-test to monitor blood glucose levels using a standard glucometer as a matter of routine, but careful monitoring is especially important when implementing a diet change.

Many veterinarians prescribe expensive diets such as Purina DM (Diabetes Management) and Science Diet m/d but you can do much better for your cat (and your pocketbook) by feeding other more nutritious - and lower carbohydrate - canned foods such as Wellness, Nature's Variety, etc. See the Proteins/Fats/Carbs chart. You should aim for a diet that derives less than 10% of its calories from carbohydrates.

  • Kidney Disease (CKD - formerly called "CRF"): Chronic kidney disease is probably the leading cause of mortality in the cat. It is troubling to think about the role that chronic dehydration may play in feline kidney failure. And remember, cats are chronically dehydrated when they are on a diet of predominantly dry food. The prescription dry 'renal diets' such as Science Diet k/d - which is commonly prescribed by veterinarians - contain only a small amount of moisture leaving your cat in a less than optimal state of water balance.

I must say that I find it truly amazing when I hear about the very large numbers of cats receiving subcutaneous fluids while being maintained on a diet of dry food. This is extremely illogical and unhealthy and every attempt should be made to get these cats on a diet that contains a higher moisture content. Please also note the following list of the first four ingredients of Science Diet dry k/d after reviewing this section on reading a pet food label - and bearing in mind that your cat is a carnivore. This is a diet that would never find its way into a food bowl owned by any cat in my care. The first three ingredients are not even meat and the fourth ingredient is a by-product meal which is not necessarily an unhealthy source of protein but it would be nice to see some muscle meat ("chicken") in this product.

Brewers rice, corn gluten meal, pork fat (preserved with mixed tocopherols and citric acid), chicken by-product meal

The purpose of this prescription diet is to restrict protein which, unfortunately, it certainly does. However, please understand that there are no studies showing that restricting protein to this level will prevent further deterioration of kidney function. k/d restricts protein to the point that the cat will often catabolize (use for fuel) his own muscle mass which results in muscle wasting and weight loss. The level of protein in this diet is not only at an extremely low level, it is in an incomplete form for a carnivore. Note that it is made up mainly of plant proteins - not meat proteins.

  • Cystitis (bladder inflammation) and Bladder/Kidney Stones: Cystitis and stones are extremely common in the cat and can be very painful and life-threatening. Cystitis can lead to inappropriate urination (urinating outside of the litter box) and stones can cause a fatal rupture of the bladder by blocking the outflow of urine.

Any cat that is repeatedly entering the litter box but not voiding any urine is in need of IMMEDIATE medical attention! This is one reason why it is so important to use a clumping litter. Clumping litter allows you to see just how much, if any, urine is being voided.

It is important to note, however, that "crystals" are not the same thing as stones. Crystals are often a normal finding in a cat's urine and it is not appropriate to put the cat on a "special urinary tract" formula when these are found in the urine.

Important: I often see too much clinical significance placed on the identification of crystals in the urine without regard to how the urine sample was handled. It is very important to understand that crystals will often form once outside of the body within a very short (one hour) period of time. If the veterinarian does not examine the urine right away and either sends it to an outside laboratory or uses a free-catch sample that the owner brought from home, an erroneous diagnosis of crystals may be made. This is called a "false positive" report and results in unnecessary worry on the part of the owner and often leads to the cat being placed on an inappropriate, low quality diet.

With regard to overall kidney and bladder health, I cannot stress strongly enough how important WATER, WATER, WATER is in both the prevention and treatment of diseases involving this organ system.

When a cat is on a diet of water-depleted dry food, they produce a more highly concentrated urine (higher urine specific gravity - USG) and they produce a lower volume of urine which means that a higher concentration of crystals will be present in the urine. This increases the chance of these crystals forming life-threatening stones. The concentrated urine and the lack of volume production can also be very irritating to the lining of the bladder wall predisposing them to painful cystitis.

Please keep in mind that a cat has a very low thirst drive and is designed to get water with their food. A diet of canned food will keep a proper amount of water flowing through the urinary tract system and help maintain its health.

If leaves keep falling on your driveway and you don’t regularly hose down or sweep your driveway, those leaves will build up and cause a problem. If you picture crystals as the leaves in this analogy, it is easy to see how canned food does a better job of ‘hosing down’ your cat’s bladder than dry food does.

Urine pH is also often considered when discussing urinary tract problems but we really need to stop focusing on pH. Again, a proper amount of water in the diet is the important issue here - not urine pH. Many of the so-called feline lower urinary tract diets are formulated to make the urine acidic but it is thought that these low magnesium, acidifying diets may actually exacerbate painful cystitis. Also, these acidifying diets, which are so often prescribed, may end up promoting calcium oxylate stones and hypokalemia (low potassium in the blood).

It is also important to note - for those people still stuck on worrying about the urine pH - that there are many factors which determine the pH of urine and only one of them is diet.

With regard to dry food and urinary tract health, aside from the lack of water in this type of diet, there is also a correlation between the consumption of a high carbohydrate diet and the formation of struvite crystals as shown by this study.

Veterinarians often prescribe Science Diet dry c/d and x/d for urinary tract problems but again, these diets are only ten percent water and contain a high level of species-inappropriate ingredients and questionable preservatives. They are also very high in carbohydrates with dry c/d containing 42 percent of its weight as carbohydrates. Please note the first few ingredients in c/d while remembering that your cat is a carnivore:

Brewers rice, chicken by-product meal, corn gluten meal, pork fat (preserved with mixed tocopherols and citric acid), chicken liver flavor, taurine, preserved with BHT and BHA

Diet is not the only issue involved with cystitis but it is an important one and one that we can control. Stress is also thought to play a very significant role in cystitis and even cats that are fed a 100 percent canned food diet may experience bouts of cystitis. This is a very frustrating disease to deal with and one that the veterinary community does not have all the answers for. What we do know is that decreasing stress and increasing the water content of the diet are the most important management issues to address. The water content of the diet is easy to control. The stress issue is another matter and is not always easy to address since cats can be very sensitive and are often 'silent' in their stress.

Cystitis can be extremely painful and it is very important to address pain management in these cats. Remember: pain = stress and we are trying to minimize the stress in these patients. Buprinex is a good choice for a pain medication. This is superior to Torbugesic which has been used for pain management in the cat in the past. (Burprinex is a prescription medication that you must get from your veterinarian.) Unfortunately, many veterinarians overlook pain medications as a very important part of the treatment of this common feline problem.

A note on antibiotic usage in these cases. Most cases of cystitis are sterile. In other words, they are not the result of an infection and should not be placed on antibiotics.

Only ~1% of cats with cystitis that are under 10 years of age have a urinary tract infection, yet many veterinarians place these patients on antibiotics when these drugs are not warranted. Most cats under 10 years of age produce a very concentrated urine (USG greater than 1.030) and bacteria do not grow well in concentrated urine.

In cats over 10 years of age, infections are more common but that still does not mean that older cats with cystitis should automatically be put on antibiotics. The reason that an older cat is more prone to urinary tract infections is because kidney disease is more common in this age group and so these cats will have a more dilute urine which is not as hostile to bacterial growth.

Diabetes and hyperthyroidism are also more common in cats over 10 years of age and both disease make the patient more prone to urinary tract infections.

A urine culture and sensitivity (C & S) should be run to check for an infection if the patient has a low urine specific gravity or is diabetic. It must be kept in mind that even with a low USG, most cases of cystitis are not due to an infection. This is why it is important to run a C & S before placing the patient on antibiotics. Antibiotics should only be used when the presence of an infection can be established.

A C & S test identifies the bacteria (if present) and tells the veterinarian which antibiotic is appropriate. The urine for a C & S needs to be obtained by way of cystocentesis which involves using a syringe and needle to obtain urine directly from the bladder. This is not a painful procedure for the cat and this method is the only way to obtain a sample for accurate information in order to properly treat with antibiotics. One problem, however, is that a sample may be difficult to obtain without waiting a few hours since cats with cystitis urinate frequently and often do not have enough urine in their bladder to get a good sample.

To get around this problem, some veterinarians will give the patient a dose of subcutaneous (just under the skin) fluids. The cat is then put into a cage without a litter box. Within a few hours, the bladder is usually full enough to obtain a urine sample via cystocentesis. This usually only takes 2-3 hours.

We have to stop treating all cases of cystitis with antibiotics without supporting evidence of an infection!

Cystitis will often recur in these patients and this painful health problem can be very frustrating to deal with. On a good note, most cats will have their clinical signs spontaneously resolve even without any treatment. In fact, it has often been said, somewhat jokingly, that a cat with cystitis will often stop exhibiting clinical signs within in seven days with treatment and in one week without treatment.

  • Inflammatory Bowel Disease (IBD): IBD can cause vomiting, diarrhea, and/or constipation in the cat. IBD can also present with weight loss as the only clinical sign. There are many unanswered questions with respect to this disease process, but it seems logical to start to “treat” a gastrointestinal problem in the cat with a species-appropriate diet. Too often these cats are treated with a high level of steroids and a prescription grain-laden, dry food diet. I feel very strongly that this common therapeutic regimen needs to be abandoned. There are an impressive number of anecdotal reports of cats that were terribly ill with IBD exhibiting dramatic improvement when ALL dry food was removed from their diet. Taking it even one step further, there are many reports of cats with IBD that improved tremendously on a balanced, grainless, raw-meat diet without any vegetables added. (See www.catnutrition.org for more information on IBD and diet. Also, see Making Cat Food for a balanced recipe.)

Robbie had severe diarrhea for two years until put on a grainless, vegetable-free, raw-meat diet.

  • Obesity: Obesity is an extremely common and very serious health problem in cats. For instance, overweight cats are four times more likely to develop diabetes than cats that are at an optimal weight. Obligate carnivores are designed to meet their energy needs with a high protein, moderate fat diet with little to no carbohydrates. Carbohydrates are minimally used for energy and those that are not used are converted to and stored as fat. The so-called “light” diets that are on the market have targeted the fat content as the nutrient to be decreased, but in doing so, the pet food manufacturers have increased the grain fraction, leading to a higher level of carbohydrates. Hence, many overweight cats eating these diets are still obese. These "light" products are among the most species-inappropriate, unhealthy diets available to cat caretakers. Many caretakers feed very small amounts of these diets hoping that their cat will lose weight but feeding a small amount of a diet that is inappropriate for the species is NOT the answer! The caretaker simply ends up with a crabby, overweight cat.

    (See Molly’s story at http://www.catnutrition.org/obesity.html and also on this site's Feline Obesity page to read how this sweet cat went from an inactive obese cat that could barely walk and could not even clean herself, to a very active and happy cat simply by transitioning her to canned Wellness. Molly now runs through the house playing like a normal cat. She can finally clean herself, and no longer limps.)

    Molly had great difficulty walking and cleaning herself due to her obese condition which was brought on by the consumption of dry food. Kittens, however, loved using her for a pillow.

    Molly’s veterinarian had prescribed Science Diet dry r/d for her and instructed her caretaker to feed Molly only very small portions - and to put a shock collar on her to keep her away from her housemates' food. This is not sound - or humane - obesity management advice. Science Diet r/d is an illogical and poor quality diet that contains 33 percent carbohydrates and the following - less than optimal - ingredients:

    Chicken by-product meal, corn meal, powdered cellulose 18.5% (a source of fiber), corn gluten meal, chicken liver flavor, vegetable oil, taurine, L-carnitine, preserved with BHT, BHA and ethoxyquin

    There are much healthier and more logical ways to address feline obesity.

  • Hepatic Lipidosis (Fatty Liver Disease): This is the most common metabolic liver disease of cats. Overweight cats that go longer than 48 hours without eating, for any reason, are in danger of developing this serious, and often fatal, disease. Feeding a high-protein, low-carbohydrate diet helps keep cats at an optimal, healthy body weight and, in turn, makes them less likely to end up with fatty liver disease.

  • Dental Disease: Long-standing claims that cats have less dental disease when they are fed dry food versus canned food are grossly overrated, inaccurate, and are not supported by recent studies. This frequently stated (among veterinarians and lay people) myth continues to harm cats by perpetuating the idea that their food bowls need to be filled up with an unhealthy diet in order to keep their teeth clean. The idea that dry food promotes dental health makes about as much sense as the idea that crunchy cookies would promote dental health in a human.

    First, dry food is hard, but brittle, and merely shatters with little to no abrasive effect on the teeth. Second, a cat's jaws and teeth are designed for shearing and tearing meat - not biting down on dry kibble. Third, many cats swallow the majority of their dry food whole.

    There are many factors – known and unknown - that contribute to dental disease in the cat such as genetics, viruses, and diet. There remain many unanswered questions concerning the fact that cats often suffer from poor dental health. However, feeding a high carbohydrate, species-inappropriate dry kibble diet is a negative factor, not a positive one.

    Dry kibble does not even come close to mimicking a cat’s normal diet of mice, birds, rabbits, etc. Given what a cat does eat in nature, it makes much more sense to be feeding part of the diet in the form of large chunks of meat (as large as you can get your cat to chew on) or gizzards which a cat’s teeth are designed to chew. Raw meat is ‘tougher’ to chew than cooked meat so I prefer to use raw meat to promote dental health. (See Making Cat Food - Dental Health.

    Notice the phrase “part of the diet” in the above sentence. It is very important to understand that plain meat (ie - without bones or another source of calcium) is very unbalanced since there is minimal calcium in meat. Remember that when a cat eats his normal prey, he is consuming the bones along with the meat.

    When fed as a supplement to most commercial canned foods, it is safe to feed ~15% of the daily calories in the form of plain meat. For example, if a cat is eating 6 ounces of canned food per day, you could feed him 5 ounces of canned food plus 1 ounce of chunked muscle meat per day.

    When people ask me “how often should my cats be fed chunks of meat?”, I reply “how often do you brush your own teeth?”

    Please understand that I am not saying that canned food is necessarily better for teeth than dry food. For optimal dental health, a cat should not be eating either canned or dry food since neither food type promotes healthy teeth but we have to work with what is practical in a typical home setting and feeding a cat a 'whole carcass prey' diet is not terribly practical - even if it would be great for their teeth. The compromise is to at least give them some muscle meat to chew on and stop fooling ourselves into thinking that dry food promotes dental health in our cats.

  • Feline Asthma/Allergic Airway Disease: Many cats have had their respiratory symptoms (coughing/difficulty breathing) subside considerably, or disappear completely, once they are placed on a canned food diet, or a meat-based home-prepared diet. Some of these struggling cats may have been reacting to storage mites or cockroach antigens that are present in dry foods, or they may have been reacting to the gluten (protein fraction) part of the grains that are present in dry foods. Sadly, many cats exhibiting debilitating lung disease are simply put on an immunosuppressive dose of steroids - while still being fed an inappropriate diet. While steroids are necessary in some cases of airway disease, they are not addressing the root of the problem which can, in many cases, be an allergy to proteins in the form of species-inappropriate grains, and insect antigens. Steroids commonly cause diabetes in cats and also render them vulnerable to infections from viruses, bacteria, and fungal agents so it is very important to make sure you have ruled out diet as a cause of the cat's respiratory symptoms.

Back to top

Robbie and Calvin flexing their muscles

The Safety of Dry Food

Dry food is far from a clean, safe, and pathogen-free source of food for your cat. Please see this section on my Making Cat Food page which details just a few of the many pet food recalls due to contamination with deadly chemicals, bacteria (salmonella, etc.), fungal mycotoxins, and storage mites.

The issue of rancid fats in dry food is also discussed on my Making Cat Food page.


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