Suzanne Phillips has been a long-time reader of this blog. Earlier this week, she offered to do a guest post on the topic of why dogs develop food allergies. Much of what you read online about this topic is utter nonsense and she decided that this would be a good venue for setting the record straight. Her analysis is entirely based upon what the scientific research says about why dogs develop allergies to certain foods. Suzanne blogs at Hoof & Paw, and she and her husband run a small animal rescue organization in Eastern Oregon called Fuzzball Rescue.
So without any further adieu, here is her post:
Photo by Suzanne Phillips. Source for image.
First, my background. I have a BS in biology with a minor in Chemistry from Oregon State University. Since becoming a veterinary technician three years ago, I’ve had dozens of hours of training and continuing education on dog and cat nutrition.
Let me put it in bold and all caps so as to head off any accusatory comments: THIS DOES NOT MAKE ME AN EXPERT. However, it’s a hell of a lot more of a solid background on this subject than most people have.
Between my science background, boots-on-the-ground experience in a vet clinic, and personal research on Pubmed and VIN, I feel confident in saying that most people who open their mouths on this subject (literally IRL, and figuratively online) have at least some misconceptions about food allergies. Some people have a lot of misconceptions. Hopefully, this will clear some of those up.
Let’s start with an explanation of food allergies. When we say a dog is allergic to a food, what that actually means is that they are allergic to one or more proteins contained in that food. A dog is not allergic to “corn”, they are allergic to one or more proteins contained in the corn. This is a huge misconception when it comes to food allergies. It’s not helped by the fact that researchers never study individual proteins, only ingredients, so as short hand they always refer to allergens by their source. Hence, a dog is said to have an allergy to “chicken”, even though it’s only a tiny fraction of the muscle meat that’s actually causing a problem.
Let me repeat that, because some people have a hard time overcoming this: allergies are not caused by carbohydrates, starch, or fats. The vast majority of food allergens are large, water-soluble glycoproteins measuring between 10,000 and 70,000 Daltons.
Protein, protein, protein.
As food is broken down in the stomach and moves to the small intestines, what’s suppose to happen is that the proteins are broken into little pieces (hopefully individual amino acids) that are small when they’re absorbed through intestinal cell walls. Instead, for whatever reason, large segments of the offending protein get through the mucosal barrier and ends up touching too much surface area of the cell walls. The body reads this as a threat, and responds accordingly. This leads to a cascade of reactions that eventually leads, strangely enough, to itchy skin, especially the skin of the face, paws, and ears, but it can effect the entire body. It can also cause GI upset such as diarrhea or vomiting, but most of the time food allergy is suspected because of itchy skin.
This is a huge problem when it comes to diagnosis (whether by a vet or by the pet owner at home) because it’s suck a freaking general symptom. Itchy skin happens for all kinds of reasons. Far too often, the dog owner sees an itchy dog and immediately assumes it’s the food. The same symptoms could be caused by a host of things that need to be ruled out first: contact and inhalant allergies (dogs don’t sneeze when they’re allergic to pollen like we do), flea bite allergy, immune disorders, mites, lice, fungal, bacterial, and yeast infections, drug reactions, and more.
People make snap diagnosis all the time. Hell, we had a client once whose dog had a classic hypothyroid hair loss pattern and insisted it was the food and refused to let us do a blood test to rule out thyroid dysfunction. They must have tried over a dozen different kibble diets trying to cure the “allergy”. Every few months they’d bring the dog in and swear the hair loss was getting better. To us, it looked the same.
Let me focus on flea bite allergy for a moment. It is a common cause for itchy skin reactions in dogs, and far too often it is dismissed by pet owners. Please, don’t dismiss it. The symptoms are similar to food allergy, the itchiness can affect the entire body even after one flea bite, and the symptoms can last for weeks. Too often, dog owner assume that it couldn’t possibly be flea allergy because they haven’t seen any fleas on their dog, or it’s the dead of winter, or because they treat their home periodically with insecticides. Fleas can live indoors just fine during the winter; they can hide in refuges indoors where insecticides haven’t penetrated, like under furniture and between couch cushions; and they can hop on a dog, have a nice blood meal, and then hop off without ever being seen.
Bottom line: rule out flea allergy in every itchy dog, every time they have an episode of itching.
What makes diagnosis of food allergy even more difficult is that a single exposure to the offending protein can cause symptoms for weeks. Possibly months. I’ve had clients tell me with confidence that they cured their dog’s allergy by switching foods. “Fido stopped itching within a week!” they say happily, “that’s how we knew Fido was allergic to Brand X Kibble.”
Sigh.
Another problem is that it’s not always clear why a dog develops a food allergy. It can happen at any age, to any ingredient, even one that’s been fed to the dog for years.
Another problem is that dogs are often allergic to more than one protein, and there are some known cross-reactivities, also. A dog who is allergic to beef muscle meat is more likely to also be allergic to beef milk. There is also potential cross-reactivities between beef, sheep/goat, and venison meats.
Yet another problem is that we don’t really know how prevalent food allergy is in dogs. One report indicates food allergy accounts for 5% of all skin diseases. Some researchers say that it’s very rare, others that it’s the second or third most common hypersensitivity reaction. Considering the difficulties in a confident diagnosis, I’m not surprised at the discord.
The only way to diagnose a food allergy with confidence is (AFTER ruling out other reasons listed above) to go on a 12 week food trial of either a specialized hydrolyzed protein diet (where the proteins are “predigested” to small sizes that won’t cause a reaction and are processed on equipment that is clean of any other food residue: examples include Hill’s Z/D Ultra or Purina HA), or a strict and well-documented novel protein diet (a diet with a single protein the dog hasn’t eaten before, and a single source of carbs that contains little or no protein, such as cornstarch or white potato). More info here.
Both ways are a pain in the ass, (no other foods allowed: no treats, no flavored toothpaste or chew toys, no flavored medications) and take forever. But, if the dog’s itching stops or is reduced within 12 weeks of the strict diet, then you can safely suspect a food allergy. Then you can, one at a time, add single ingredients back into the diet until one (or more) of them causes a reaction. If you’re lucky, it’s only one or two ingredients that can be easily avoided in the future.
According the best research out there, the most common food to cause allergies in dogs is (probably) beef. This doesn’t make beef “highly allergenic”, it means that, of the population of (studied) dogs with food allergies, it is the most common ingredient that they reacted to them. However, there are millions of unique proteins in the ingredients in dog foods, and only a few ingredients have been studied thus far.
Food allergies are an immune disorder of individual dogs. Just because some dogs are allergic to beef, doesn’t mean beef is inherently “bad”. The food itself doesn’t cause dogs to be allergic.
The flaw is in the dog’s body, not in the food.
Lastly, I want to talk about Public Enemy Number One for a moment, simply because I’m sick to death of clients and dog aficionados talking crap about it: CORN.
Corn does not “cause” food allergies. It is not even one of the most common (known) food allergens. Corn is not “filler” in kibbles; it has all kinds of nutritional value for dogs: B vitamins, fatty acids, protein (corn gluten meal is 60% protein), and, of course, carbohydrates. Which dogs can digest just fine. Sorry if you don’t like that fact. Forget the recent study about amylase production in dogs and wolves; and stop speculating about specific paths of evolution and just consider the simple reality of kibble digestibility studies. Every major pet food company has done at least some kind of digestibility study on at least some of their foods. In fact, all the ones that market to vet clinics (like Purina, Hills, for example) make a big deal out of this fact. Kibble is highly digestible for the majority of dogs. The end.
In conclusion.
Things you should stop saying:
“It’s unnatural for dogs to eat carbs and it makes their skin itchy and flakey.”
Things you can feel free to say:
“I feed my dog XYZ and they seem to do well on it, so I think I’ll continue.”
If you only read one article about food allergies, read this one:
Verlinden, et al. 2006. Food Allergy in Dogs and Cats: A review. Clinical Reviews in Food Science and Nutrition, 46:259-27
Thanks for an interesting and informative piece.
I’ve never had, and so far as I know, I have never bred a dog with food allergies. I’d like to keep it that way.
Can you add anything about the reasons for allergies? To what degree are they hereditary? Do they have anything to do with homozygosity in the MHC/DLA?
I feed lola a very clean diet- and rotate protein sources- turkey, chicken, fish, beef. I do half raw and have low carb dry or dehydrated dry. When I adopted her she was very itchy- previous owners had her on purina dry only. Today her coat is full and healthy.
Why do dogs mostly never develop allergies? I have never had a dog with them, is it genetics ?
In humans, the current thinking is that there is a window of time during which infants are susceptible to developing food allergies. There are lines of laboratory Beagles specifically bred to be reactive to foods, so there *can be* a strong hereditary component. My own thinking, due to reading and observation, is that there are a couple of different roads (reasons behind) to food allergy in dogs. I agree with Strombeck that a lot of allergies, especially in dogs that have an allergy to one or two things and never develop another one, is due to early weaning onto complicated foods with many proteins, which causes problems with developing oral tolerance. Some dogs may have a slower maturation rate for the development of oral tolerance and when bombarded with different proteins at three weeks old, poof, allergy.
I’ve written on allergies twice; neither of those articles gets many links. Dog people don’t like to hear the truth.
Your articles on allergies are really good, actually. It’s changed the way I feed my dogs, certainly. I’m also glad that both of mine weren’t weaned early.
I am finding the gut microbiome really interesting right now. Lots of fascinating research going on with comensal bacteria.
Yeah, I haven’t done as much reading about the *causes* of food allergy, although there’s some evidence that other diseases which cause inflammation of the mucosal barrier can lead to FA. None of the sources I read can agree on if there are certain breeds which are truely “prone” to having them, which surprises me. Every single (adult) English bulldog I’ve ever met has GI problems and itchy, yeasty skin, and chronic ear infections. And, simply from the patients we’ve diagnosed with FA, most seem to be either labs, boxers, or pit bulls.
I have come to believe, through experience and reading (the literature is mostly on human allergies and it is a chore, plus conflicting) that there are allergies and there are ALLERGIES. IOW, allergies precipitated by not forming oral tolerance as a puppy and which are easily dealt with by removing the offending food are one thing, and a dog with a hyperactive immune system that forms new allergies at the drop of a hat (or has environmental allergies) are different kettles of fish. There are probably grades in between.
Purely on anecdote, it is possible to breed a dog with food allergy and not produce pups with food allergies if you wean them correctly. This jives with Strombeck (though he is out of date, we know that the gut starts closing within 4 hours of birth now.)
It is a fascinating subject, especially when you throw the microbiome into the mix.
short faces are link to gastric issues , so i’d guess itchy skin is something to do with how the gut extracts nutrition ?
P.s. can you recommend any references that will be accessible to the general public? I can only find the abstract for Verlinden at al on line.
Every other dog-owner discussing her dog is “allergic to this and can eat that” . .. hate it. But after all that, people like to think their dogs are humans and feed them lots of grains – “they need fibre” – and diary. Due to that, their dogs are a bit ill all the time, they are itchy or so. Also, their poop is soft, actually and many times far too soft. But these people think it is a good / normal thing. Also, the amount of the poop is stunning.
That sucks. It is no good thing.
I’ve fed few times my dogs with WHOLE rabbits and WHOLE water fowls and so SEEN the thing with my own eyes. The poop was PERFECT, very dark, very dry, but not hard, did not smelled bad. And – it wasn’t a big heap, not at all ! So, it was like a wild dog’s
The great allergy-debate is a sign of the medicalisation of the time. If one dog has 3-5 enzymes and the other 15, I’d never call it some f*** allergy, when it’s just diversity.
I found the full article (.pdf) here: http://cms.evsrl.it/SocSpec/SiteTailorCommon/ShowBinary.aspx?id=3350
Giraffe, I’m confused. Are you saying that dogs who are fed grains are “itchy all the time”? If so, that’s exactly the misconception I tried to correct in the article.
When you say that a food “makes a dog itchy” what you’re saying is that they have a food allergy. And very few dogs actually have a food allergy to any type of grain.
Having hundreds of dogs living nearby, having known many owners for yrs, it’s easy know what’s happening. They feed their dogs wrong, then they go “oh, it’s a little scour..”. This can go on for yrs. Some have even diagnosed pancreas, liver or guts spoiled for unknown reason, relatively young.
One lurcher bitch had diarrhea – was itchy for yrs. She then was tested – it was the diary and that was called off. Now the dog’s better. Many people keep boasting how they give sour milk “because it makes so good for the tummy”. Shit – I bet lactose-breaking enzyme is significantly rarer in dogs than in us .
So, people do feed their dogs like they were humans – too much wrong ingredients . Is this fact so hard to get ? I don’t care to wise off about this item. We have had allergy in the family and it’s a serious thing. But these, these I tell you here are not allergy but manifestation of the diversity of the dog genome today .
Some problems in coat and health are possibly also caused by nutritional deficiency, especially if they’ve been feeding the same kibble consistently for a long time and the dog doesn’t have a lot of variety in its diet.
Of course they are. But you know, most dogs in the world are fed very cheap. That’s how it is and has been. I don’t feel pity, dogs were born to eat our scraps.
I’m assuming that when certain proteins don’t get broken down sufficiently, its because of enzyme deficiency of one kind or another?
That can happen, but the gut barrier is not perfect and neither is digestion. There are ALWAYS intact proteins getting through. The trick is that the body develops oral tolerance; ie “Oh, HEY WHAT’S THAT? Oh, never mind, seen that before, nothing to worry about.” It doesn’t see the intact protein as an invader, thus no antibodies formed against it, thus no allergic reaction.
“Oh, HEY WHAT’S THAT? Oh, never mind, seen that before, nothing to worry about.” It doesn’t see the intact protein as an invader, thus no antibodies formed against it, thus no allergic reaction.”
It’s interesting that you mention this. I emailed Monica Segal once about why, despite their development and use by some vets, a lot of other vets don’t recommend allergy testing because it often doesn’t correlate with real-life reactions. In other words, your dog might be having an allergy to something that the test says there is a low reaction to or even no reaction to, and vice-versa.
Her reply was that dogs create antibodies to EVERY protein they consume, and that as a result, a dog that, say, has been eating a lot of turkey lately, if you tested it, could come up with high reaction values for turkey, but not necessarily having a real-life allergic reaction to it.
This alone prompted me to purchase a veterinary text on immunology! It’s such a complex issue.
Yes, exactly! That’s why the gold standard is still the elimination diet, and will likely always be the elimination diet.
Reblogged this on A Bitter Cynoanarchist Rages On and commented:
Good article on food allergies. Read.
I don’t understand what DesertWindHounds is saying. . But, allergy is a oversensitivity to some natural, everyday occuring small particles in the environment. It’s very close to the rheumatic illnessess, causing inflammation in the body, due to a gene fault, that makes the body to build shelter (antibodies) against a supposed “invander”.
Lack of some enzymes in a dog’s guts is not allergy. Also, I can’t tolerate white bread, but I’d never call it allergy.
But all the other people over here in my town, country, even in the world does (SIGH).
So that the thing the (too) long blog was explaining ? I think those jerks didn’t read it, if they did, they didn’t get the point.
Are you calling me a jerk? No, really, I’m asking.
Yeah, geeze Jess, quit being such a science jerk. ;)
Researchers are still sorting out the causes of FA, but no, it’s not JUST a problem with digestion, or a problem JUST with inflammation or other problem of the mucosal barrier, but those things allow a FA to occur.
And food allergy is similar, but not the same as, say, anaphalactic reaction to a drug or a food substance (peanut allergy in people, for example, when the substance touches the skin and sets off both localized and systemic immune response).
Food allergy only happens when the food proteins of a certain size manage to touch parts of the small intestine of a dog that is sensitized to them. Dog’s who are allergic to beef won’t have a reaction if you rub raw beef all over their skin.
“Dog’s who are allergic to beef won’t have a reaction if you rub raw beef all over their skin.”
Now you have me wondering if vet science knows this is true for certain. Ex: I have human friends who are so allergic to certain foods, that they will have a rash at the very least, if they even touch the foods they are allergic to.
FA is a different mechanism from that kind of allergic reaction. FA only occurs when the offending protein contacts the intestines – it won’t have any effect when it touches other parts of the body. FA also doesn’t trigger life-threatening anaphalactic reactions, just the cascade of effects that end in itchy skin.
This is excellent information. Thank you so much for educating us about this. Some things I knew, but, not all. I will pass it along. :-)
Hm. I have a particularly itchy Sheltie–and I ALWAYS assumed it was flea and inhalant allergies–never food. Because he starts scratching his hair off in late summer/early fall. I try not to treat for fleas unless I ABSOLUTELY have to, so at that point he gets a Comfortis (because I have found that actually works, at least so far–the topicals don’t work for me) and if the itching doesn’t completely stop, he also goes on Prednisone for a bit. Once we have had a good freeze, he doesn’t tend to have inhalant allergies anymore.
I have other dogs in the same line who have neither flea nor inhalant allergies, so while it is inherited, this particular dog is neutered (and I can trace back to a great-grand who, unfortunately, has had a lot of progeny and is known to have allergies. Flea allergies, while they suck, don’t worry me quite as much as inhalant allergies in dogs–you have a much better chance of controlling fleas than of keeping your dog away from grasses and pollens!
Dogs with environmental allergies often have food allergies as well. It’s not uncommon. Dealing with the food allergies can actually make the environmental allergies easier to deal with as it removes one of the sources of inflammation in the body.
He doesn’t have any problems in the winter and early spring, though–coat comes back in, and he looks and seems to feel great until he gets that first flea bite in late July or early August.
I’ve been told there is also a difference between food allergies (adverse reaction to an ingredient) and food intolerances (ingredient cannot be processed properly), and that most dogs actually have intolerances not allergies. That doesn’t seem to fit with the information presented here, can anyone clarify this for me?
An intolerance is non-immunological. It’s not a reaction by the immune system. Intolerances often involve gastro problems instead of skin problems. For most purposes, people just want their pet to be comfortable, so it doesn’t really matter whether the problem is an intolerance or a true allergy. Eliminating the offending food is the key to resolving the issue in either case.
Intolerances can be harder to diagnose because they can be dose dependent. For instance, a dog can each some chicken, but not every day. Or they can eat a small amount of something (a few bites) but not a whole meal. Intolerance is the one instance in which rotating foods may actually ‘work’, by avoiding the triggering amount of food.
Yeah, there’s another article to be written about food intolerance. :) It’s a term used for a much broader set of problems, though, including things we’d call “food poisoning” (dog raids trash, eats bacteria-laden food, throws up = a food intolerance).
I’m not sure about “most” dogs having one or the other, though, as there’s not great stats on prevalence of either one.
One of the studies (if you search for the full study) has as its first footnote that it must be labeled as an advertisement.
Another compares the digestion of minks, fox, dogs – and was funded by a pet food company and presented at a pet food conference. I personally don’t own a mink or a fox, so I’m not sure of the relevance.
Having had a dog with a severe flea allergy that required lifelong daily steroids from the age of 3, I second the suggestion to rule this out first. The thing I learned is always treat the house rather than the dog as if you spray your house with the long lasting IGR type sprays every 6 to 9 months, they won’t get a foothold. If you see one on the dog, it’s too late as the little blighters will already be breeding in the carpets and crevices. Also treat all the cats and dogs in the house, not just the sufferer that’s biting themselves raw. If you have cats that roam, they are often the culprit for bringing home “guests”.
This is just my personal experience so doesn’t constitute advice in any way. I’ve had several dogs with food intolerances and allergies, but shar-pei have dodgy immune systems to begin with and food is often the first culprit with them if they are itchy. The one with the flea allergy was a collie cross and didn’t seem to react to food when the vet suggested experimenting with diet. The chow I had was just an expensive, atopic mess who responded well to a lamb & rice diet. The TM was intolerant to high levels of protein in puppy food as a puppy. As soon as I put him on an adult lamb & rice kibble at 20% protein, he stopped pooing sludge within a few hours. I found with my shar-pei, they have had varying skin, ear and digestive reactions to kibbles with beef, wheat, soya and maize that cleared up if they were given rice or potato based kibble. I had one that was violently digestively intolerant of chicken, all of them have vomited bile in the morning on lamb & rice based kibbles and they generally do better with turkey or duck as the meat component, rice or potato as the carb and the kibble being good quality, around 18-20% protein and with as few extra ingredients as possible. I used to drive myself to distraction worrying about dog food and reading dubious guff on the internet. Now I just aim for my dog looking in good coat and bodily condition with the food being firm, compact in size and not revolting to the nostrils both on the way in and out. A good quality kibble covers this and costs less than cheaper food in the long run in several ways.
It would be very interesting to see if breeds originating in different parts of the world had different abilities to process amylase as anecdotally, the Oriental breeds I’ve had seem to process grain associated with their part of the world better.
I am a huge fan of IGR sprays for flea control around the house (I also like using topicals). They’re relatively low in toxicity for mammals, are unlikely to contaminate ground water, and they work for long-term control (with re-application) without actually leaving a residue for years and years like pyrethroid insecticides do.
My own dog has flea allergy, in fact she just got over a bout of itchiness from when she picked up some bites at my parents’ house three weeks ago, so I’m always careful about flea control.
What’s an IGR? It’s not hitting me. :)
Insect Growth Regulator:
http://en.wikipedia.org/wiki/Insect_growth_regulator
I appreciate all this information, especially that the difference between “allergy” and “intolerance” is explained.
I have a dog that has a sensitivity to chicken-based feeds that manifests as excessive tearing. I refer to her as “chicken-allergic” because people seem to understand that if she gets the wrong food she will have a reaction, and people don’t want to make a dog uncomfortable if it can be avoided. I suspect if I start saying she is “chicken-intolerant” others will envision something truly horrible and maybe dangerous overtaking her, rather than just her eyes getting runny. So I’m going to stick with “chicken-allergic” even though it is not technically correct, or maybe I’ll try saying she has a “sensitivity to chicken.”
My dogs have never been able to tolerate a lamb-based feed; the result is digestive upset whose details you would rather I spare you. They don’t like beef or pork (as a kibble base) and will eat bison and venison but not with enthusiasm. All enjoy turkey, duck, and fish-based kibbles. The one with the sensitivity to chicken is fine if she gets chicken treats now and then, including the occasional raw wing or drummie. I did not understand how that could be possible (sensitive to chicken in kibble but not raw or in treats in limited quantities) but thanks to this discussion I can now grasp the reason.
Great information here, and I thank all who are contributing their science-based knowledge.
Overall, this is a very informative post and very well-written (except for a couple of spelling or grammar errors here and there).
From what I’ve seen, it seems that food allergies is a topic that not many dog owners look into properly. Most owners, when they see their dog scratching, they think it must be fleas, and then get stuck if and when they treat their dogs for fleas and the itching continues.
Anyway, food allergies are just one of the common causes for a dog’s itchy skin, and yes, as you say, it is, in actual fact, caused by just a small factor of the food and not the food as a whole, but oftentimes, it may just be easier to avoid the ingredient as a whole. Right?
It is often advised that if your dog is suspected to have a certain sensitivity to an ingredient, to feed your dog a bland diet (such as boiled chicken and rice) for a while, and then slowly start feeding your dog its original food to rule out the culprit food. How do you feel about that? Is this true?
Your blog seems like a large rant. The tone of it, overall, seems quite frustrated to me. It is unfortunate that not everyone holds a Degree in Science, isn’t it? So not everyone has the resources to know the scientific reaction that causes a ‘food allergy’. Having said that, we are all grateful that you decided to share your knowledge and research with us.
My goodness… getting a bit shrill, are we?
Having read any number of dog food commentaries, from “this happened to my dog” to outright diatribes, particularly as to the demonic traits and food value of various grains, I was pleased that Ms. Phillips explained that she was not merely relating a personal theory but has academic credentials to provide a foundation for her findings. A lot of people who share their absolute conclusions about such matters have no apparent basis beyond how their dog fared on one food as opposed to another to offer as “expertise,” but they fancy themselves as experts nonetheless.
While degrees and career milestones alone don’t necessarily make one an expert in any field of endeavor, they can serve as a sort of yardstick for a reader in sorting out the value of the information offered. In this case, they gave me more confidence in referring others to the post in hopes that someone else would have an “Aha! moment,” as I did.
I hold a Degree in English, so it comes naturally to me to criticise and to challenge. I don’t mean for anyone to take it personally. I was just a little surprised by the apparent tone. I guess not so dissimilar to how you responded to mine.
And I did state that I am grateful for the share of knowledge, and I truly mean it. However, I just felt, personally, that some of it seemed more like a rant, attacking people that think their dog could have a food intolerance or allergy. It is, nevertheless, just my opinion.
[...] found this piece by Suzanne Phillips, posted on The Retriever, Dog, & Wildlife Blog very interesting and worth the [...]
I applaud this explanation of how proteins affect dogs.
I’m a raw feeder. Unlike many, I’m not the type to go chastising folks for not feeding their dogs exactly as I feed my own. Every dog is different, every owner does as they think best ( for the better outcome or worse), and every dog in a home where an owner cares is damned well luckier than thousands of dogs that roam dangerous streets worldwide, has their lives cut short in a kill shelter or is eaten in an Asian restaurant of some sort.
I do hold that I am not sure I agree with the statement that corn is not a filler in dog food. It’s one of the biggest commodities in the USA and so overproduced, that it often sits around in storage. Yes, dogs eat our scraps, and based on this and the agreeable price, dog food companies have had no problem buying it up for kibble. Sure it has some nutrition, but hardly enough for companies to not have to add vitamins and minerals by the time the extruding and heating processes have taken place.
I’m sure there’s a better list out there somewhere, but if you scroll down here the nutrition chart really doesn’t impress me for corn. There is a decent amount of potassium and a couple of B vitamins, but it’s not rich in much else. And I imagine that’s corn in its just-harvested form. http://en.wikipedia.org/wiki/Maize
I’ve heard that wild corn grown in Central and South America was far more nutritious, but I guess that’s neither here nor there now. I would love to find something that compares the various forms over time though.
At any rate, I don’t doubt corn was picked for it’s low price over real concern for dogs. Testing digestibility? Well, what choice do the companies have on that one? If dogs can’t digest it they get sick from it, and that’s not good for sales. It’s natural for any company to want to save money, but there are far better sources of nutrition even in hydrolyzed form. Heck, it took forever for companies just to put in more meat MEALS over corn.
Monica Segal is an experienced animal nutritionist, who goes by National Research Council standards over the AAFCO standards, on the preimse that NRC standards are superior. She consults folks on feeding homemade, raw and cooked diets but has nothing against dog food when a hydrolyzed food for a sensitive dog needs it. It’s about the dog, but just as much about the reality of standards for dog food.
BTW, I have a Master’s in bio. I’m not a vet tech but I can go through the PubMed postings as easily as anyone else. I can say I have known actual vets and PhDs who, after all the science, will defnitely refer to simpler, broader wisdoms like, real food is a better go-to for all living things, and you get what you pay for. How many nutritionists concur that eating fresh, real foods rather than overprocessed foods with vitamins thrown in is better for you? How many times have we heard from scientifically trained nutritionists that most of added vitamins just get taken out in the urine, unused by the body, compared to that taken in when you eat real food?
There is a part in the article that says to blame the dog, not the food, if an allergy takes place. I’m glad for that, because while the purpose seemed to start out to strictly explain how proteins caused allergies, it ended with a tone that can leave some with the impression that corn is as good as anything else, and that dog food is preferable over real food. Why do only dogs and cats seem to get this distinction, of suddenly being the only animals on the planet unable to make it on real food?
I don’t deny the role of genetics in a lot of the problems with dogs today. I also don’t deny that a lot of owners won’t take the time to learn proper nutrition if they choose to feed their dogs themselves. That’s a condition of the times we live in, where people feel they can’t get enough time for themselves, have to watch pennies and simply grew up knowing only commerical pet food. That’s a problem with the owners, not with the food.
Just felt I had to say these things.
Came back to add something from a trained professional in animal nutrition. She cites corn and soy as sources of hard-to-digest protein, and all in all, they are cheap additives. I don’t know that this means they are more likely to cause allergies, but it does speak to the seemingly broader-based defense of corn in dog food as insufficient, to say the least.
Read “About The Author” to the left if you want to know her background and that she has at least some science-based education.
And also read the “myths” part if you need assurance that she is fair-minded Many of these myths she breaks would anger some of the varieties of raw food purists who insist that all dogs should be fed like wolves.
http://www.dogfoodproject.com/index.php?page=protein_myth
Corn and soy aren’t “filler” and aren’t “hard-to-digest”… necessarily. Once processed, they can be very digestible for dogs.
Is corn cheap? Oh yeah. Is that probably the main reason it’s used in dog food? Yes. Is it the best ingredient to use for dog food? Probably not. Does that mean it doesn’t contain nutrients that a dog can digest and utilize? No. That’s why I pointed out digestibility studies.
Corn has an extremely bad rap right now, and there are many myths circulating about it by people who want to feel superior via what they feed their dogs. Corn is not just “filler”; it doesn’t cause food allergies or “itchy skin” (which people forget is short hand for food allergy), and isn’t even one of the top allergens compared to meat sources. That’s my only point when I brought up corn. I get annoyed by these oft-repeated myths, even though I’m not personally a fan of corn in dog food in general.
That’s fine Suzy. There’s nothing you wrote here that my points did not already cover.
This is what Sabine Contreras has to say about corn:
“Corn often gets an undeserved bad reputation. While it is not acceptable as a main source of protein in a dog food (as it is used in combination with corn gluten), as a source of carbohydrates it is no better and no worse than other grains in terms of nutritional value and digestibility. The starch part of corn is highly digestible but the whole ground product has a higher fiber content than other grains (around 7%), which results in slightly larger stools – often incorrectly interpreted as lack of digestibility. Unless an individual dog is intolerant or allergic to corn, there is no need to avoid products which include it in reasonable amounts.”
http://www.dogfoodproject.com/index.php?page=betterproducts
My dogs get white corn grits in their mush meal, with white rice and rolled oats. It does not constitute a large portion of their diet. I initially fed grits because corn, unlike rice, doesn’t cause a large post meal insulin spike and I wanted to see if my dogs would be less hyper after a meal. (This did not work. You know what makes dogs less hyper after a meal? Aging.) Because they do fine on them, and digest them well, and it allowed me to reduce the amount of white rice in the diet, I kept the grits.
Note that grits do not contain the outer hull, which is what people are generally referring to when they state that corn is ‘hard to digest.’
Good article, well explained. I too will pass it along.
I actually did one better for Suzy, just to be fair. I emailed the author of the blog I linked to and asked her WHY corn proteins are hard to digest. For all I know she used that phrase in passing as just another way of expressing that corn is a cheap, generally inferior food.
For a dog that has serious issues with a lot of meat proteins, if the animal can eat corn, utilize the protein and carbs and not itch or have another lousy reaction, then sure, it’s great. And I get that the dog has the problem, not the foods. But strictly speaking, corn has a few nutrients, but it’s hardly the most nutritious food out there, as I pointed out earlier.
Also to be fair, I DO have my own corn-related pet peeve. I hear a lot of people swearing that their dogs react to eating meat from corn-fed animals where they don’t have problems with the same meat from grass-fed animals that never touched corn.
The only way I could see this being even remotely applicable would have to do with the Omega-fatty acid ratios. Supposedly they are different in grass-fed animals and there have been at least a few studies documenting that yes, there are in fact, changes to these ratios depending on what has been fed. I also will concur that the eggs I buy from truly pastured chickens seems to be more flavorful, and a deeper orange, and I’ve seen at least one study that showed nutritional differences regarding Omega fatty acids, though I cannot find it now. I DID find these at a whim:
http://www.ncbi.nlm.nih.gov/pubmed/20393997
http://paleohacks.com/questions/146894/is-the-color-of-an-egg-yolk-really-the-best-indicator-of-nutritional-value#axzz2Shc14thw
My issue with all of this is, people swear by grass-fed animals being the key to itch prevention, as if the animals that eat corn BECOME the corn; like somehow whatever is in the corn that they feel causes itching becomes a PART of that food animal their dogs eat, retaining their structural integrity in part or whole.
Food provides building blocks and every animal that eats them takes what they need of it and reassembles it in the body in the way it’s needed. How corn vs grass changes this process, well, don’t ask me.
If grass-fed animals have a higher Omega 3 acid content, perhaps the anti-inflammatory properties do have some effect. But does the protein structure of the food-animal change? I doubt it. I would suspect that change in basic amino acid chains could/would have much worse consequences for the
health or viability of the food-animal.
It’s a lot like the shark cartilage craze. That stuff was sold based on the statement “Sharks don’t get cancer”, so as a result, shark cartilage supplement demands skyrocketed. Eating shark cartilage means you break down whatever building blocks are there and using whatever your body is programmed to take and reassemble into the normal, healthy parts and functions HUMANS are designed to have. You may be able to make use of some of the collagen at best, but your human cartilage will still function like human cartilage. It won’t BECOME shark cartilage and it won’t prevent tumour growth.
Meanwhile, sharks are becoming more endangered as a group than ever before, due to overfishing. Even if the shark cartilage boom was spurred by the byprodcuts of shark harvest, those byproducts are now a high-demand product in and of themselves, so I don’t see the endangerment settling anytime soon. Myths do cause damage, from religious wars to shark population threats, to the last tigers being hunted for their penises so a few aging, wealthy Chinese men can get through their mid-life crises.
“Sharks don’t get cancer, so eat shark meat and make them go extinct so you won’t get cancer!”
One of the greatest scams ever!
Especially since sharks DO get cancer! https://www.sharksavers.org/en/education/biology/myth-sharks-don-t-get-cancer/
“Also to be fair, I DO have my own corn-related pet peeve. I hear a lot of people swearing that their dogs react to eating meat from corn-fed animals where they don’t have problems with the same meat from grass-fed animals that never touched corn.”
I hate to be rude (I’m lying) but most people are full of shit. They frequently see what they want to see, when they want to see it, and real circumstances be damned (homeopathy comes to mind.) Having to eat very expensive meat makes their dogs Very Speshul. Simply buying ‘regular’ meat and adding an omega 3 supplement like fish oil isn’t Speshul.
IOW, people are generally very poor at observations (and very good at correlation, which is not causation), unless they are very good at record-keeping and keep a daily accounting of foods/symptoms, exposures, etc. I have rarely found a pet owner that had a pet that wasn’t seriously or chronically ill that kept good records (yes, I am thinking of the woman who claimed to have cured ‘thousands’ of rescue dogs with a raw diet, yet could not supply a single record when I asked.)
I won’t get into the human psychology behind HAVING to spend Lots of Money for Your Very Speshul Dog, unlike those Other People, who don’t, and therefore are not as Speshul As You Are.
I don’t think it’s always about speshul! LOL! Good spelling! Sometimes, sure it is. Now, I do feel good about feeding my dog real food. I do think nutrition plays an important role in health for all. I just refuse to get smug about it. That’s a good way to lose friends and NOT influence people!
I’ve spoken to many people who just honestly, lovingly, try to do the best they can by their pets. I’ve spoken to some dog owners who are practically bankrupting themselves in an effort to provide some pretty high-standard raw diets, etc. Their dogs clearly mean a lot to them. Maybe those animals are all they have.
On the other hand, there are a lot of militants out there regarding feeding. Sorry but until we can get past wars and the use of nerve gas in Syria and the alleged use of Uranium-weapons in Fallujah, I think the topic of whether or not dogs get grass-fed meat can take a back seat. I’ve tried to obtain it for my dog, and will if I can, but oftentimes that just isn’t happening. Sometimes I can barely afford it for myself!!! Economic reality needs to be looked at too.
I do think a lot of people who get disappointed by conventional medicine’s limitations look to alternatives not being embraced by their local hospital out of fear or frustration. The drug companies pumping-out of loads of drugs, quickly, with side effects, and their profit margins, fuel this fear. To some extent I don’t blame people, and sure, if there is a gentler way to deal with something that could be provided by a certain diet or an herb, I’d be sure to get on board.
But that’s IF it really works, not just because it’s going around online with no thought to where it came from. And sometimes, unfortunately, people get ailments for which there are simply few options, and it’s naturally hard for people to accept. Giving up a fight and accepting a bad situation can lead to depression.
The complexity of the real situation behind health and disease can also be too mind boggling for acceptance. A lot of natural alternatives offer simplicity that is appealing to the overwhelmed and frightened; offers peace. The danger is when it leads them away from looking at reality, yes; real treatments that can be useful.Trying to tell these people that homepathy is infinitessimal amounts of herbs in water is hard. There a ton of anecdotes where people swear homeopathy helped. Bad note taking? Probably. ARe nanoparticles effective? There’s enough evidence for metals leaching from certain hip implants – chromium/cobalt/molybendum – in the parts per BILLION causing issues, for law firms to be waging suits. Granted that’s a metal, but the body passes other metals in greater amounts without serious issue. So I’d be up for the study of CERTAIN plant properties in homepathic amounts to see if they do help things.
Of course, the one thing people don’t seem to get, when they just stick Pharma in the mind as enemy-only is, being profit driven, if there WAS something to the herbals some folks swear by, wouldn’t it stand to reason that Pfizer and the lot would have jumped on them and found a way to profit by them?
The other big mantra is carbs-feed-cancer. This has been elevated to carbs CAUSE cancer. It’s not just limited to sugar, too much of which is no good for you according to standard science. Even whole grains like Amaranth, Quinoa, lentils, are being called out as the source of inflammation behind many maladies. I want to know where this theory originated from. No one seems to be able to tell me.
Sabine of The Pet Food Project wrote back. The last line of her response referst to the National Research Council. Both Sabine, and nutritional counselor Monica Segal, use their guidelines for dog nutrition because they say it’s a body of indepdenent scientists, and they find that using their standards is better than AAFCO standards, which as far as I ever heard, only requires 30 test animals and just wants most of them to not die from living off the food they eat.
Mind you, I only asked about protein digestibility. The carbs in corn never came into question in my mind.
” There are several factors that play into protein quality and how hard it is to digest.
One of them is the difference of the ingested and fecal nitrogen to the ingested nitrogen, which is expressed as a percentage. Of course this must be corrected for the portion of non-dietary origin (metabolic nitrogen). This is usually demonstrated by testing in a metabolic cage.
Protein efficiency ratio in growing juveniles is also an obvious measure, e.g. feeding test diets containing corn vs. other protein sources and observing their growth and physical development. This is a bit flawed though, since the age of the test animals plays an important role.
The level of insoluble fiber and concentrations of antinutritional factors (“antinturients”) is another factor.
It’s been demonstrated that animal-based proteins generally have a higher digestibility than plant-based ones, with dairy protein ranking at the top.
I think you will find the NRC publication very interesting, with lots of sources cited. ”
http://www.nationalacademies.org/about/whoweare/index.html
Page from Sabine’s site regarding protein in general. http://www.dogfoodproject.com/index.php?page=protein_myth