Like many things that happen in our lives and our pet's lives there is a genetic component that we cannot change – our destiny. But our genetic destiny and our pet's genetic destiny can be modified by life events and lifestyle. You have a lot of control over that when it comes to a group of chronic inflammatory disease that affect our dogs and cats.
The increased diagnosis of chronic digestive tract issues in our cats and dogs have paralleled the switch from natural foods to mass produced canned and dry pet foods. These issues are rarely – if ever seen in dogs and cats in other parts of the world that do not follow those trends. In those areas, it is intestinal parasites and virus causing intestinal inflammations that are the problems. Here, periodic broad-spectrum pet wormers have eliminated that issue in pampered pets. Chronic intestinal health issues are now one of the major disease confronting cat owners and their veterinarians. (ref)
Dogs, probably because of their longer association with man and human diets, suffer these issues to a lesser extent - over time, they have experienced genetic mutations that allow them to process carbohydrates better. (ref1, ref2) However, that ability is not uniform among dog breeds or individual dogs. (ref 1, ref 2) Cats became our partners considerably later. (ref)
There are almost always some signs of an impending digestive tract problem while your pet is still in its youth. You might write it off to a case of indigestion, fur balls, etc. But generally, these problems get worse with increasing years – not better.
The general thought among the veterinary research community is that the chronic inflammatory digestive tract problems that cats and dogs experience are quite similar in their origin to those in humans. (ref) But since very little deep research on these problems have been conducted in the veterinary community, I relied on advances in understanding the chronic diarrheas of humans – what causes them and how they can be successfully treated. Basic metabolic and immune processes do not differ much between you and your pet and that knowledge has been used successfully by veterinarians many times in the past. Us humans do have many adaptations that allow us to process starches and sugars better than our cats and dogs. But when the process fails, it can fail in the same general ways in all of us. One significant study at Texas A&M did determine that two species of bacteria decreased in number during periods of diarrhea in dogs (ref), a more recent study found significant differences in the bacteria residing in normal dogs and those with diarrhea. However, the samples did not indicate if the diarrhea was a one-time occurrence or a chronic problem. (ref) As in humans, bacterial diversity in pets with intestinal issues tends to go down. (ref)
In humans, we know that inflammatory bowel sufferers probably have certain mutations in their Interleukin-10 genes. (ref) Interleukin-10 puts limits on the inflammatory process. Creatures deficient it are susceptible to run-away inflammation. In Nature, gene mutations are not always bad. Sometimes we later find that those mutations persist from generation to generation because having them confers advantages as well as disadvantages. But dogs and cats , like humans, have been removed from genetic selection for positive health traits for a long time. So there may be no benefit whatsoever in certain individuals being more susceptible to IBD and other food-related digestive system issues. A similar deficiency occurs in mice - that I'll get to later. I do not believe anyone has examined the specific genetic issues that increase the susceptibility of dogs and cats to long-term digestive tract inflammation; but veterinarians know that certain breeds of dogs, because of their genetics, are more susceptible to inflammatory bowel disease than others. (ref)
Inflammatory colorectal polyps in dachshunds are thought to constitute a breed-specific form of inflammatory bowel disease. Dachshunds appear to be genetically predisposed to this form of the disease. About a third had evidence of gastrointestinal inflammation as well. (rptref)
Because of the likelihood of a genetic component, if one kitten or puppy in a litter develops chronic intestinal issues, it is somewhat more likely that others in that familial line will as well – just as in humans. (ref) That is reason enough that those parent animals should not be bred again.
I will try.
The money and scientific infrastructure to examine the causes of IBD in dogs and cats is limited. The “Big Five” Pet food companies (Mars, Nestle/Purina, Del monte, Colgate Palmolive and Proctor & Gamble) have very deep pockets. But there is no incentive for them to fund research that might well be destructive to their business model.
Things are different on the human side of the isle. (ref) I spent much of my career with the NIH. Several things had become obvious to human health researchers at the NIH. The first was that the development of successful medications to treat people for IBD would require a much better understanding of the processes that drive it. The second was that there was obviously a substantial genetic component to IBD that had to examined – it often ran in families. (ref)
But the third was that there must be life-triggers that caused the disease to appear in humans that were genetically susceptible to it. There have been substantial human migrations over the last 30 years – Asians moving west into central Europe, populations moving north from Ethiopia to the Middle East, Far-Eastern Europeans moving west after the collapse of the USSR. In all cases, doctors saw an unusually high number of people developing IBD and related intestinal issues when their diet changed to the ones we tend to consume in the west. (ref1, ref2, ref3)
No one has ever proposed that the basic processes at work in the digestive system of your dog and cat are that different from those occurring in you. That is particularly true of the immune system – which every mammal possesses.
We now know that the living organisms (bacteria, protozoa, fungi = all are the microflora) present in your pet’s intestine (particularly its large intestine which is more friendly to their survival) constantly interact with the immune system cells in the intestinal wall that surround them. It is critical that the proper mix of these organisms exist to suppress the bad ones among them. The “normal mix” is dependent on the nutrients passing through the digestive tract which is dependent on what ingredients the animal consumes. (ref) That mixture of microorganisms changes based on what you feed your pet - carbohydrates favor one bacterial menagerie, proteins another. Your pet’s immune system is constantly monitoring what passes through its intestine. In circumstances where the bacterial mix is wrong or where food components (like carbohydrates and food additives) modify intestinal conditions, the microflora can be pushed outside of the norm for the species. In those situations, the animal's immune system can make errors and identify a basically non-threatening food, bacterial ingredient or even its own tissue (autoimmune disease) as a threat. (ref) Once identified as such, a process of intestinal inflammation begins that can be very difficult to stop – even when the original source of the error is no longer present. Errors like these don’t only occur in the intestine. They are the basis of all autoimmune diseases.
It told me that several of the ingredients in commercial dog and cat foods have the potential to encourage chronic gastrointestinal problems and that we ought to look at that issue more closely.
An key immune system constituent in the antibody producing process I just discussed is Interleukin 10. It role is to keep the process from getting out of hand. Despite what some humane advocates suggest, health research – yours and your pet’s – is still dependent on animal models. Not every thing can be accomplished in a pet ri dish. The IBD research community knew that. In the early 1990s, a laboratory mouse was develop in Cologne, Germany (ref) that could not produce Interleukin 10 and so, was highly susceptible to IBD. (ref) This type of mouse is called a knockout mouse.
These mice all develop inflammatory bowl disease. But they do so faster when certain things are done to them. Some animal models develop diseases that appear to be the same as those that occur in humans and our pets. But later it is found that the similarities were only superficial. That is not the case with this mouse - the same drugs that block the key IBD process in humans, block it in these mice. (ref)
The two most important drug breakthroughs in medical treatment in the last 10 years have been FDA approval of MABs that block intestinal inflammation and the JAX-inhibitor compounds. The Xeljans you see advertised on TV for rheumatoid arthritis and the Apoquel your vet told you about are two JAX-inhibitors. Remicade and and Humira, promoted for human IBD, are MABs. MABs have not entered the veterinary market yet – probably due their extreme costs (~ $144,000 a year for Remicade; $20,000/year for Humira). How medications like Apoquel might affect these chronic diarrheas in pets remains unknown. (If your pet takes Apoquel for allergic dermatitis and its IBD issues improve, let me know.)
I do not know of any published data regarding the use of MAB drugs in dogs or cats. But Anti-TNF is a mab and from the little work that has been done, they appear to act the same in dogs as in humans. (ref 1, ref2)
Your pet’s intestine must be a permeable sieve to let nutrients in. But invaders want in too. Your pet’s body must have guards present to regulate what gets through their intestinal wall and what doesn’t. That is part of the duty of the immune system present in the intestinal walls. In pets with many of the chronic intestinal inflammation issues like IBD, the immune system mistakes food, bacteria, and other materials in the intestinal tract for foreign substances and responds by sending white blood cells into the lining of the bowels. The result of the immune system's attacks is chronic inflammation. You see that is diarrhea, weight loss and vomiting. Eventually, but not always, chronic inflammation morphs into cancer. Thickened, inflamed intestines do not absorb nutrients well. So a host of sighs of malnutrition are also possible. (ref)
Intestinal inflammation is not always driven by mistakes in your pet’s immune system. Many compounds present in processed pet foods are irritating in their own right. Read about that below.
“Every” is never a good word to use in medicine – the body and the influences of the world around it are just too complex. Even an anxious personality type has been linked to intestinal issues in us people. (ref1, ref2)
I have seen the same in dogs and cats.
I had the occasion to walk down the pet food isle at PetsMart last week. I asked the clerk which were the two most expensive premium brands they sold and had a look at their ingredients. One of the premium brands of canned and dry cat food that caught my eye had a wild lynx on the label. I have worked with wild feline for over 50 years. (ref1, ref2) After reading that can’s ingredients, I can assure you that that lynx would not thrive on it. It would develop diarrhea and its teeth would fall out at an early age. That house cats manage to survive on it is a tribute to your house cat resilience - not what is in the can. (rptref)
Both top brand’s labels were flashy and impressive. Obviously, a lot of thought and effort had been spent on their design appeal. Pet food manufacturers and business schools know that you pet owners love your pets dearly and want to feed them what you yourself would want to eat – not what science and nature tell us that they ought to eat. (ref) But the microscopically- printed ingredient labels that were, on first glance, impressive were considerably less so when one took some time to consider them.
First, the brands both tout that they are 100% Grain Free !! (ref) Ok…. But grain isn’t the problem, the problem is that cats, and to some extent dogs, can have problems metabolizing carbohydrates. There are plenty of carbohydrates in these cans and kibble that are not grain – like the potato. The meat portion is spit into its various sources to push the potatoes farther down the list. The potato and the potato's starch are separately listed. Do you know why ? Because most consumers already know the ingredients are listed in the order of their amount in the product. (In a beauty pageant you always want your best looking stars at the front of the lineup) ....... A lot of flax seed too. It does have some good omega 3s and antioxidants, but its 29% carbohydrate. Protein is 10% of the total product weight in the can and fat is 8%.
Both brands contained the additives, carrageenan, cassia and guar gum.
Their dry cat foods were 33-36% protein and 8-16% fat. Their plentiful carbs were supplied by potatoes, sweet potatoes, peas, brown rice and tapioca . You notice they never give the carbohydrate content on the labels. Their dog foods were less protein and fat intense – but contained the same ingredients. The canned foods were mostly water, but calculated on a dry weight basis, there was 36-45% protein and 29-36 % fat in the cans.
Lets do some comparisons:
Using the USDA food tables, one can calculate that dried fat-trimmed boneless chuck beef would be 75.7% protein and 24% % fat. Its carbohydrate and sugar content is zero (ref) Dried, skinless chicken breast would be 75.7% protein and 24% fat. Its carbohydrate and sugar content is also zero (ref) Raw wild Atlantic salmon, dried, would be 56.5% protein and 20% fat with negligible carbohydrates as well. (ref)
The difference between the 33-36% in the pet foods and the 75% in the USDA meats are almost all added carbohydrates. (The weight of the vitamins and the trendy health and the wellness stuff (ref) in the bag or can are close to negligible.)
The amount of carbohydrate in the food you feed your dog or cat has a crucial influence on the types of bacteria that are prevalent in its intestines. (ref)
Humans tolerate - even thrive on carbohydrates. Our pets have different needs. The ability to tolerate high carbohydrate diets is most developed in dogs. It is very poorly developed in cats (ref) and totally lacking in ferrets. I referenced earlier that recent studies have found that many dogs have evolved to metabolize carbohydrates rather well. (rept ref) But the author of that study admitted that although many dogs do metabolize starch well, he had no evidence one way or the other that suggested it was good for them and pointed out that some dog breeds did it better than others. There are two important forms of carbohydrates, first the sugars and starches and second the fermentable fibers like the beet pulp you see on the label. The presence of either or both influence which bacteria will thrive in the intestine. (ref) Most dogs tolerate moderate amounts of starch in their diets, but sugars and starches have major negative consequences for cats. The second form of carbohydrate, fiber (cellulose), can have beneficial effects in producing regular bowel movements in dogs and cats, as it does in humans or in a weight loss plan designed for your pet.
Due to its carnivorous nature, your cat does not possess the metabolic pathways necessary to process starches and sugars efficiently. When you ask your cat to metabolize carbohydrates (starches and sugars), you are asking your pet to do things that the Creator did not intend for it to do. That has consequences. (ref) These carbohydrate-packed diets that fill your grocer's shelves also encourage obesity (particularly in cats but in dogs as well). That overweight condition may be cute in Garfield; but it encourages inflammation throughout your pet's body (by encouraging the formation of pro-inflammatory cytokines) (ref) [just as it does in humans. (ref)]
Low carbohydrate diets have already proven their worth when cats develop diabetes (rptref) - and many believe the high carbohydrates in commercial cat foods, along with the obesity they generate, are the cause as well. Veterinarians have also noticed a link between inflammatory bowel disease and pancreatitis in cats. (ref1, ref2) Even the most common liver disease in cats, (hepatic lipidosis) , has been linked to these obesity-generating, carbohydrate-packed commercial cat diets. (ref) Humans with chronic bowel inflammation are four times as likely to develop pancreatitis as well (ref)
There are two reasons: The cost of ingredients and the manufacturing process. In the case of canned products, only the first applies.
1) The pet food and pharmaceuticals market are among the most profitable consumer product industries in the world. (ref) Keeping ingredient costs down and purchase price high is a time-honored way to do that.
2) Dry pet foods are generally made by mixing the ingredients and pressing them through a small opening (die extrusion) at high temperatures. In this process, carbohydrates act as the glue to bind the other ingredients together. I am not an extrusion technologist; but I believe that if the large pet food companies could produce a profitable dry kibble product for dogs and cats with more than 36% protein they would have already done so. They are not ones to neglect a potential market. The only company I know of with the philosophy, manufacturing techniques and incentives to get around that is Wysong.
Most small animal nutritionists are either employed by the pet food manufacturers or work in the nutrition departments of veterinary colleges. Those within the industry obviously concentrate on furthering the broad goals of their employers. Those within the education community usually rely on funding from the pet food manufacturing industry to conduct their research and maintain their departments. What would you do?
You yourself probably eat many of these ingredients as well. However, you do not eat them day in and day out in large quantities. Development of the little knock out mouse I told you about has made it much easier to tell which of the products have the potential to trigger a malfunction of your pet’s intestinal immune system.
You already know that a typical can of cat or dog food is about two-thirds (78%) water. That appears to be about the maximum the producers can conceal in their products. Pet food manufacturers know that pet-owner perception is everything and that you wouldn’t be happy if you opened the can and saw that the top two-thirds was water. So they add emulsifiers to distribute the water evenly, and jellying products to thicken it up.
However, there is a growing body of evidence that these emulsifying/thickening products have the potential drastically alter the type and number of bacteria found in your pet’s intestine. (ref) They are also thought have the potential to encourage inflammatory bowel disease by stripping the pet’s intestinal wall of its protective mucus layer. That allows bacteria and other pet food ingredients to have a much closer position to your pet’s immune system cells – forcing the system to make snap decisions regarding the many potential food antigens pet foods contain. (ref) Some of these additives are irritating in their own right.
Pet food manufacturers and their fellow travelers will reply that all these additives have been approved by the FDA. That is true. However, most of those studies were done long ago, long before the rise in intestinal inflammation problems occurred and before scientists had any knowledge of how the immune system’s memory functioned.
The most common emulsifiers/thickeners in canned pet foods are carrageenan, cassia gum, guar gum, cellulose gum/ (aka carboxymethylcellulose), and xanthan gum that you might see on the ingredient labels. The kelp and saccharina are probably added to perform a similar thickening function – not because of any known healthful effects in dogs or cats.
In one study, carrageenan, at least in the presence of other cancer-causing agents, was thought to accelerate the disease in animals. (ref) Its pro-inflammatory effects in humans are troubling too. (ref)
Guar gum is economical because it has almost eight times the water-thickening potency of cornstarch - only a very small quantity is needed for producing a stiff texture in almost anything. It is used a lot in the food industry but the biggest use today is in the petroleum fracking process where it is injected into the ground and in sewage plant water purification. It appears to have the potential to be irritating in its own right and to sensitize the immune system. (ref1, ref2)
maltodextrin is another thickening and binding agent. It is often used in commercial pet treats (particularly the soft or chewy ones, It is also the most major ingredient in the Fresh Breath Cat Treats sold at Petsmart). It too was found to found to disrupt the colon’s mucus barrier and allow bacteria to cling to the intestinal wall. (ref1, ref2)
When the meats used in pet foods are initially processed, they are dried by exposure to significant heat. When the cans containing the final product are sterilized, they are exposed to further heat. When dry pet foods are extruded into pellets, they are exposed to temperatures of up to 170C (some sources say temperatures reach 204C) to bond the ingredients together. Heating meat to high temperatures causes the generation of two groups of chemicals known to stimulate cancer, HCAs (heterocyclic amines) and PAHs (polycyclic aromatic hydrocarbons). HCAs are thought to begin to form in meat at about 150C. The longer the meat remain at high temperature, the more it is formed. We know these compounds are suspects in the cause of colon cancer in humans. In one study, chronic intestinal inflammation preceding that made people 6 times more likely to develop it. (ref) How and if this relates to intestinal disease in cats and dogs I cannot say because no one has examined the issue. (Others, with considerably more knowledge of the pet food manufacturing process than I have, feel that there are more important concerns [ref])
Dogs and cats handle animal fat in their diets better than we do. They seem to be immune to the fat-associated cardiovascular problems humans are prone to.
Cats in particular require substantial amounts of fat in their diets – more than is found in lean meat. Dogs do not need as high a level, but handle 10-15% well. (Too much fat in your cat's diet may be just as undesirable as too little [ref].)
However, if vomiting, upper intestinal inflammation or pancreatic, liver or gall bladder disease are part of your pets health issues, it may not be able to absorb or tolerate fats as well as healthy dogs and cats (those pets may need a multivitamin supplement because of their reduced ability to absorb vitamins). (ref) That's something you need to discuss with your veterinarian.
Commercial dog and cat foods do not contain natural, unrendered animal fat. They can contain animal and vegetable fats that have been "hardened" by passing hydrogen gas through them. Such fats are called hydrogenated. After the process, they contain varying amounts of trans-fat. One study found that trans fats had the ability to cause liver damage in cats. (ref) Because of health concerns, the FDA banned the use of trans fats in all human food in 2015. (ref) However, at the request of animal food industry lobbying interests, pet foods were exempted from this ruling.
It is normal for cats to nibble on fiber now and then. In the wild, about 26-20% of the feces of these animals contain small to moderate amounts of grass and other native plant material. (ref1, ref2). Perhaps it aids in bowel movement regularity - we really do not know. Commercial pet foods add highly processed sugar beet fiber to their diets. (ref) If you prepare your cat's diet at home, I suggest you use Fibrex instead. (Cultivated vegetables and fruit are too high in simple sugars and carbohydrates. In quantity, they are not a suitable alternative.) Extra fiber can contribute to healthy weight loss; but too much will lead to flatulence, soft stools, diarrhea, and malnutrition. (I personally would not encourage your overweight cat to reach its ideal weight in less than six months - particularly if its health is already compromised. But other knowledgeable vets are comfortable with more dramatic weight loss [ref])
By all means do so. Many pets improve or go into remission when their diets are changed. You already know that my preference is for diets you prepare at home. Those are the only diets whose ingredients are fully under your control.
But once your pet’s immune system decides that a compound is a threat to its body, that decision becomes part of your pets immunological memory , that can be hard or impossible to erase. It is another facet of the same immunological memory that protects your pet against infectious disease. That memory is why your dog – once it is successfully vaccinated against parvo or your cat –successfully vaccinated again panleukopenia or you vaccinated against polio never needs a vaccination again to remain protected. These immunologically memories can be suppressed by drugs like prednisone, Atopica and Apoquel , but they can probably never be fully erased.
It can be quite difficult for the veterinary pathologists receiving biopsy samples from your pet to tell the difference between inflammatory bowel disease and the early stages of lymphoma cancer. (ref1, ref2, ref3) Cat owners write to me frequently. In the cases where the chronic inflammatory problem has progressed to true cancer the pets have never lived long. I tend to discourage owners from having cytotoxic drugs or quack remedies given to those pets. Time gained, if any, tends to be short. That doesn’t mean that drugs with less severe side effects will not be available in the future. There is great potential here – but the costs of such drugs are quite phenomenal. (ref)
Of the 42 different bacteria types identified in the stools of health dogs, none are included in the probiotic pastes and additives sold for dogs and cats. (ref table 2) There appears to be very little difference between the normal intestinal flora of cats and the normal intestinal flora of dogs. (ref) (A fecal transplant would be more appropriate. But I have only done them in rabbits. [ref])
None of the commercial therapeutic diets formulated for dogs and cats address what we now know about the importance of the dog and cat biome or our current understanding of the probable causes of inflammatory bowel disease and chronic diarrheas in dogs and cats.
Inflammatory GIT problems are no doubt multifactorial problems (due to a combination of things). As in all multifactorial problems, where you can only control one factor (variable), the diet, you can not always expect dramatic results. The changes you see are likely to be subtle. Don’t expect sudden, dramatic changes in your pet – like a winning strategy in poker or gin, they only show there benefits over time. Over a pet’s lifetime, those health changes and minimized risks can be significant. We do not know if the changes found in the gut (intestinal) wall in chronic inflammatory conditions can be fully reversed. Once immune memory cells are programmed, they may stay programmed regardless of withdrawal of the original stimulant or offender. We just don’t know yet.
Like home schooling, it gives the control back to you. But like home schooling, you have to be quite committed and educate yourself. You will have to sort through the tremendous amount of information, disinformation, hype and scientifically unproven claims found on the Internet and in print. I would not rely on the advice of those who offer to sell you their amazing products and supplements with great hype and fanfare.
The pet food industry, your veterinary product distributors and their many fellow travelers in the AVMA will do their best to scare you out of it. They will hold up the specter of salmonella and nutritional deficits in an attempt to frighten you. They will insinuating that even enlightened pet owners do not have enough common sense to prepare a nutritionally complete diet. Do you call your nutritionist every time you prepare a meal for yourself or your children ?
Lest you rush out and purchase the ingredients and plan to feed them to your pet raw, remember that feeding raw meat ingredients can present its own dangers – particularly to pets that are already in ill health. Those worries are even greater when it is some commercial fortified raw product stocked in a merchant’s cooler. Although some folks successfully feed raw, I would lightly cook all meat products and select the individual ingredients myself. (ref)