Episode 143: Food Allergies with Purina, Part 2

This is an audio version of a webinar we hosted on our Facebook page. To see the accompanying slides, view the recording here.

Food allergies can be frustrating for pet owners and veterinarians alike. They often share clinical signs with environmental allergies and can be difficult to differentiate. This podcast discusses the prevalence and diagnostic approach to food allergy, focusing primarily on the elimination diet and the supporting evidence to integrate and maximize the benefit of diet into a successful treatment plan.

Transcript

Nicole Engelman [0:30] Thank you all for coming today and taking the time to join us for this presentation, Food: Friend or Foe? Using Diet to Your Advantage with our guest, Dr. Jason Gagné, who has joined us for a few webinars in the past. He is a board-certified veterinary nutritionist at Purina. We really presented this and decided to come up with this topic today because of feedback from members of our community. You want to hear more about canine nutrition, especially food allergies. That was the reasoning behind this presentation today. During the Q&A segment of this presentation, we’re going to be prioritizing the previously-submitted questions from our community first. When we announced this about a week ago, we received some really great questions from all of you, so we’re going to be prioritizing answering those at the end of this. Before I kick things off, I just want to share a little bit more information about Good Dog for anyone who is joining us that might not be familiar with who we are and what we do. Good Dog is on a mission to build a better world for our dogs and the people who love them by advocating for dog breeders, educating the public, and promoting canine health and responsible dog ownership. We are a secure online community, created just for dog breeders, and we are completely free for dog breeders as well. We use the power of technology to help good breeders really level up their breeding programs by providing them with tools like our secure payment system to protect them from scams, software to post your available litters and connect with really amazing Good Dog applicants to find great homes for your pups, and we also offer additional breeder business resources like webinars about navigating taxes as they relate to dog breeders (that’s been a very popular one), search engine optimization, and much more. If you’re not yet a member of our community, we would absolutely love to have you join us, and we invite you to learn more at gooddog.com/join. With all of that, I will pass things off to Dr. Gagné and get the presentation started. 

Dr. Jason Gagné [2:40] Since it is problematic for owners doing the home-cooked diet, this was given rise to years ago by food companies coming out with commercial novel protein diets: the lamb diet, the fish diet, etc. As time has gone on, so many companies have created their own lamb diet (let’s say). Lamb is no longer novel. So it’s difficult to find a true novel protein. Who’s to say that the dog doesn’t become allergic to that new protein? That can and does happen, actually. As we look at the homemade diet, the way that’s made up is usually a novel protein. If you take a dietary history: “Okay, my dog hasn’t eaten venison.” So we make up a venison diet. We put in there a protein to carb ratio (usually 2:1 or 1:1) and add in a vegetable (like soybean oil to get the essential fatty acids for the skin and coat), maybe balance that out with fish oil, and a few other ingredients. The advantage to the homemade diet is that the owner is for it. They usually are gung-ho at first. We know what we're putting into the diet. We’re avoiding the preservatives and the additives. Some owners really want to be part of that therapeutic plan. It’s actually really rewarding for me, as a nutritionist, to work with owners doing this and getting the feedback as we go along the way and adding an ingredient in week by week by week. I keep in touch with them as we go along. The disadvantage to this, though, is that while they are gung-ho at first (and we do talk about how laborious and tedious this can be or you’re dedicating a Sunday to it every week), once they start doing it, they truly understand at that point. It is a major increased effort. If you’re doing it on your own and not consulting with the right person, it could be incomplete or unbalanced. Are we really choosing something truly novel? Has the complete dietary history been taken? For the sake of time, I’m going to move on from this stance there. 

The novel protein diets did come around well into the 1970s and 1980s and really placed a stake in the ground to say, “We can make a therapeutic diet here with manufacturing an environment that has clean conveyors, has standard operating procedures to ensure that we’re not cross-contaminating proteins.” Smaller companies that aren’t therapeutics aren’t necessarily doing that, so when you’re looking at something over the counter and you see it says “Venison and Potato” (let’s say), 99 times out of 100, yes, it’s venison and potato. But there’s been studies out there showing that there are other proteins in there. They’re not necessarily cleaning the lines of conveyors like the therapeutic diets do. That is an issue. That’s caused a lot of proteins to be scratched off the list as novel. Again, there are some disadvantages here. Is it truly novel? But again, for the sake of time, moving on. Where we would place these two diets in regard to our elimination diet options that we mentioned before—the categories of the non-antigenic, complete & balanced, palatable, and convenient categories, you could see where I have the pluses and minuses. Maybe they are, maybe they’re not antigenic. Clean and balancing—maybe, maybe not with homemade diets. Homemade diets certainly are not convenient. This has given rise to saying, “Could we make a different type of diet?” This is where hydrolyzed protein diets have come into play. What that is is basically taking those intact proteins that we talked about before (those green squiggly lines on the left) and breaking them into smaller pieces so that when they do bind to that IGE antibody on that mass cell, they don’t cross. You cut them up—this big protein into smaller and smaller and smaller pieces. The gist is you’re flying under the radar of the immune system. You get the same nutritional benefits, but you don’t get the immune reaction. There have been studies actually showing that soy and purified corn starch have been very successful here and fed to dogs years ago that were known soy allergic and known corn allergic dogs, where they did an allergen-free diet (totally make-believe diet, but it’s allergen-free). That was your plus diet, a positive control. Back when Purina HA was being developed, the results here were, when fed the allergen diet, there’s an increase in their level of itchiness here on this scale. When they were fed without allergen, they dropped way down. But when they were fed the hydrolyzed diet, they dropped by 50% for the soy allergic dogs and 80% for the corn allergic dogs, which was fascinating. This was followed by other studies with hydrolyzed diets showing the efficacy of them. This was an interesting study where dogs were either fed what’s considered an intestinal diet, versus dogs fed a hydrolyzed protein diet. They followed these dogs out for 3 years. It was a 2-3 month re-check, a 6-12 month re-check, and a 3 year re-check. That’s interesting, to follow a dog out for 3 years. What they noticed here was on that first re-check of 2-3 months, these dogs on the intestinal or control diet—75% complete control, 12.5% partial—with the hydrolyzed protein diet, similar results: you’re talking around 88%, almost 90% recovered. But as you get out to the second re-check, only 28% recovered on the control diet, whereas all 100% were covered on the hydrolyzed diet. As you go to the 3 year mark, still all 100% recovered by the hydrolyzed diet and only 12% by the control diet. Hydrolyzed diets gained quite a bit of popularity. They still are the mainstay, if you’re going to be feeding a therapeutic diet for food allergies. This was a study by Stan Marks at UC–Davis back in the day that looked at dogs with IBD (those vomiting and diarrhea signs) and showing the improvement over time in their fecal scores, so there were these 6 dogs that started out with a fecal score—this was a scale of 0-100, 0 being watery and 100 being form—they all firmed up to 100 by feeding that Purina HA diet. This dog up here (you’re not going to notice it because he was a vomiter, but his vomiting improved) went from 100 to 100. This dog here is what’s known as a Exocrine Pancreatic Insufficiency German Shepherd (EPI dog)—that did firm up quite well on a hydrolyzed diet alone. That’s fascinating: just from diet alone.

Regardless, HA diet, hydrolyzed protein diet, complete and balanced—we all know if I was to say, “Plug this hydrolyzed protein category into the rubric we talked about earlier,” I still have the possibility that this could be antigenic. This is because as you hydrolyze diets, maybe you don’t hydrolyze 100% of it. It’s almost impossible to hydrolyze 100%. Let’s say you hydrolyze 98%—is that 2% enough to trigger that dog? Maybe. We all have different tolerances. This gave rise to what’s known as the amino acid-based elemental diet that Purina launched back in late October of 2021. It’s an amino acid-based diet. Purina is part of the Nestle family. It’s a global R&D. They’ve been using amino acid products very successfully in pediatrics for a number of years. This technology was applied to pet food with elemental. The idea here is that you have an intact protein that causes a mass cell to degranulate; hydrolyzed protein should be fairly foolproof. But amino acids—they don’t even bind to that IGE. In terms of the dalton size, we talked about the 10,000 and 70,000—hydrolyzed tend to be 2,000-12,000. Amino acid is around 134. It’s nothing. They don’t even bind to the IGE receptors. They’re not going to cause a degranulation. Honestly, if you’re allergic to an amino acid, I don’t think you’re compatible with life.

Moving on here, this elemental concept takes care of the idea of “I didn’t take the dietary history. I don’t know if the dog is allergic to pork or venison or whatever I’m choosing.” You don’t have to worry about that. If they’re sensitized to multiple allergens (pork, beef, dairy, whatever), this still takes care of that. As I mentioned, sometimes hydrolyzed diets may not be 100% hydrolyzed so it takes care of that issue, too. So, going to the rubric, if I plug it in there, it does cover that non-antigenic—it does check that box. We did do a study with this. It’s through review now. It’s going to be published in Journal of Vet Internal Medicine: 23 dogs. Alison Manchester is an internist, specifically gastroenterologist interested in aminos at Colorado State University. He performed this study. It was a pretty awesome study. Dogs with chronic enteropathy—she had done endoscopies, scoped them, shown they had chronic enteropathy to definitively diagnose them. Then we followed them through for 8 weeks’ time. She did show that 16/22 (73%) experienced complete relief. There was one dog that did refuse the diet. They always have one dog out there that’s waiting to say, “I don’t like the taste of this diet!” There were a few that did have inadequate relief. They’re not food-responsive dogs. They needed pharma at that point. It was palatable to 95% of the dogs. Great study that’s going to be published. Features this amino acid-based diet. It has a very low allergen carbohydrate source. It has corn starch and tapioca starch, so it meets that less than half a percent intact protein criteria. Lower in fat because the lower fat is really important to the GI dogs specifically. The type of fat—medium chain triglycerides—is a passive absorption of fat. It’s complete and balanced for both growth and adult. Food allergy dogs—as early as 4 months. That’s why we formulated it to growth. You can see the digestibility here. It makes complete sense that it would be that digestible, but wow. When we got those numbers, they were really significant. The most-manufacturing testing occurs to make sure it’s not cross-contaminated with any proteins as well. 

That’s all I got. I hope that’s been informative. I hope you find some practical tips in there and really stressing back and forth between the owner and the veterinarian and the vet to the owner about really being strict about an elimination diet and what the dog is consuming for that 8-12 week period. Really, I can’t stress that enough. Thank you for your time.

NE [13:02] Thank you so much for such a fantastic and really informative presentation. I learned so much. I’m sure our viewers did as well. In the last 10 minutes, we do have a few questions for you if that’s okay. I am going to start with some of our previously-submitted ones. Our first question is: If dogs seem to have more itchy reactions to formulations with chicken, is salmon a better alternative?

JG [13:28] Yes, and no. Chicken is the most prevalent, probably because there are more foods out there that contain chicken than salmon. If you’re finding a salmon pet food out there that is over the counter, do bear in mind—I would consider those more limited ingredients than novel protein. The salmon may be novel to your dog, but the salmon may have also been made on the same line where they just made chicken, and therefore, there is still some chicken diluted into the salmon diet, if that makes sense. If you truly want to feed a therapeutic diet for this—and that’s really the way to go. If you can’t do the homemade diet that’s complete and balanced by a nutritionist, the way to go is that prescription diet. Those are only available through vets or prescriptions that you can get on Chewy or wherever. But it’s got to be a prescription diet at that point. 

NE [14:20] We have another chicken question. Chicken is a very popular topic in our questions. This person is wondering if the antibiotics that are administered to some animals that end up in dog food, such as chicken—is that going to have a trickle-down effect on the dog that is eating that food? 

JG [14:38] If the chicken is given an antibiotic? 

NE [14:40] Exactly.

JG [14:41] That biomagnification has not been shown in pet foods to affect dogs. 

NE [14:52] Last chicken question. I believe you answered this, but this person might have not heard: Are chicken or beef allergies more common for dogs? 

JG [15:00] I think we’re splitting hairs there. They’re both equal. Years ago, it was beef then chicken. As of 2016, which is the most up-to-date review paper from the derm folks, chicken is ahead of beef. But you’re splitting hairs there. When I do my nutrition consults, I have people that say, “You know what? My dog is doing great on ground beef right now. I really want to stick with this.” Honestly, I’ve done it enough times where I say, “Sure. Let’s do that. I don’t think it’s going to work out.” They push back, and I say, “Okay, you’re going to come back to me in a couple of months,” and they do. I would avoid chicken and beef both when we’re talking about an elimination diet trial. That’s why you’re going to see, with the hydrolyzed protein diets, ⅔ of them are working out of hydrolyzed soy because soy is so uncommon to be allergic to. If you hydrolyze it and break it down into smaller pieces, it’s even less common to be allergic to. We want to create it as foolproof as possible. Unfortunately, even that’s not foolproof, and that’s why that amino acid diet exists now.

NE [16:02] Awesome. Thank you for answering that one. Many people in our audience are obviously dog breeders that are listening to this, and I’m sure many of them are wondering: are there certain breeds that are more likely to suffer from food allergies than others? 

JG [16:15] Yes. That has been recorded. However, I would say that that is a mixed bag. I would say that it’s really any breed. It’s even mixed breeds that it can happen to. I don’t like to pigeonhole and say it’s specific breeds, because the minute I do that, someone is showing me a mixed breed dog that has food allergies. I don’t mean to be evasive on that, but it’s something that we should just be cognizant of that can happen to any dog. 

NE [16:44] Good to know. Another question that might apply to a lot of our dog breeders here. You mentioned that food allergies can occur to a dog at any age. Is there an age where food allergies are most likely to occur? Can a breeder even see that as they’re introducing food to their puppies for the first time?

JG [16:59] It’s typically young. When I say 4 months old to 17 months old, it’s typically in the puppy stage. Some literature says up to 6 years. I’d say you’d typically see it up to 2. If you start splitting the percentages out of where you see them, 2 years and younger is the biggest portion. 

NE [17:20] Got it. A few questions have come in about hydrolyzed diets. I think that’s a very fascinating concept in and of itself. One of them is: can a dog stay on a hydrolyzed diet long term? 

JG [17:31] Oh yeah. If the formula is formulated to maintenance, which all of them are in, in the case of the hydrolyzed realm, yes. That is something. If the dog is doing well on it, and you’ve diagnosed through an elimination diet trial—okay, my dog is doing great! Stay on it for life. 

NE [17:45] Similar question, still on the topic of hydrolyzed diets: I know when dog owners or anyone that’s going through an elimination trial diet with their dog, they still want to be able to offer them treats. Are there any hydrolyzed treats that can be offered during a diet trial? 

JG [18:02] Typically yes. I will say, as we know—me, personally working for a pet food manufacturer—Purina’s does not exist right now. It was discontinued in February for a variety of reasons, but it is coming back in January of next year. Hills does have one as well. I do believe that that one is available at this time. 

NE [18:23] Awesome. Got to make sure the dogs have their treats, even if they’re on their elimination diet! 

JG [18:31] I’m still saying the treat becomes the diet. I’m that conservative with it. People are like, “Can I give a probiotic during the elimination diet?” No. No. No. They’re like, “Why not?” I’m like, “It’s just a variant. Get rid of it for now.” Fish oil is one thing. Fats have never been recorded to be a cause. It doesn’t chemically make sense that a fat would be the cause of an allergy. So usually when it comes to fish oil, I’m like, “Okay, you can stay on that.” But very few and far between do I say, “You can stay on that.”

NE [18:58] Similarly, with that in mind, are there any medications that can be given to offer relief when starting an elimination diet trial? Or is that going to impact the trial as well? 

JG [19:09] We have to face reality. The dog is having clinical signs. We have to be very practical about this. Particularly when it comes to the skin, you’re going to possibly be talking about antibiotics and antifungals. I leave that generally to the general practitioner or the dermatologist, if you’re seeing that specialist, to decide that, but yeah. That, too, may have to be given in conjunction with the elimination diet trial. Depending on the length that it’s given, it may actually extend the elimination diet trial. That’s where we say 8-12 weeks. Typically it’s a 4-week period that the vet is giving something like that, for the antibiotic, for the skin. And then we say, “You know what? You’re giving that now. That’s going to be a 4-week trial. That’s why I’m pushing you from 8-12 weeks, to have a full 8 weeks of diet.” The GI signs, depending on the severity of what that is, that can be protein losing enteropathy, these more severe GI conditions. You better be given some immune modulating/immune suppressing medication there. As I do my consults, I think 90% of that type of consult—those internists are giving those medications. I consult with the owners and say, “We’re going to see as we go along during this next 8-12 weeks, whether you can wean down on that.” Inevitably, they come back to me and say, “Can I wean down on it? My dog is doing better.” I say, “That’s not me. That’s your internist. Go back to them.” They’re going back and forth between us to re-check the blood work, to show the improvements. But that’s really more the internists role or whoever prescribed the drug.

NE [20:50] Amazing! Thank you very much for answering that one. I believe we have time for two more. This question came up, again because of our breeder audience: With newborn babies, we are told to start feeding new food slowly to watch for allergies. What are your thoughts on allergic reactions in young puppies, and what should we feed mothers so allergens are not passed to puppies? 

JG [21:11] I’m not sure we really know that answer: what to feed mom. Me, when it comes to reproduction, nutrition as related to gestation and lactation—you better be feeding energy-dense food to begin with. That lactation period is the most energy-demanding phase of a dog’s life, so it’s got to be something that’s energy-dense. It can be something over the counter. In a Purina line, we’re feeding Purina Pro Plan 30/20, and it works great. Every pet food, though, has their own food for that. When we’re talking about the pup, though, what we like to say there is make sure that they’re getting mother’s milk. The colostrum, etc. They are not immune-competent when they’re born, like you and me. Different species, different immune competencies. Just make sure they’re getting the mother’s milk and that they’re growing appropriately. There is no rhyme or reason to that. What I would say—what I’ll insert there, if you’ll allow me—is to make sure that we’re not giving antibiotics unnecessarily. We need to be better at antimicrobial stewardship and really asking ourselves: Do we need that medication? That’s been shown to really, really wipe out the GI microbiome, those bugs that provide us benefits that are in our colon. There’s some good work going on in that realm. We have a partnership with Texas A&M University, the GI microbiome lab there, and we’re actually looking at that with them at this point in more of a long-term status.

NE [22:43] Very cool! It’s very cool to hear how all of these things are a work in progress and always advancing.

JG [22:48] Science continues.

NE [22:52] Love it. So I have one more question for you. This is my question, but I think it ties this whole presentation together. 

JG [23:00] Uh oh.

NE [23:01] I know. I’m stealing the spotlight for a second. Can you think of food allergies as ever being cured or is it something that can just be managed for the lifetime of your dog?

JG [23:10] That’s tough. Because of the fact that we know we don’t know everything. The answer is both there. You can manage them for life. That has been shown. You can manage them through nutrition alone, in many cases, for life. For some dogs, you’re going to manage them through nutrition and drugs. That’s just the reality. You decrease the amount of meds that you’re on, decrease the side effects (that’s the goal), and it’s both to manage for life. However, there is this subset of dogs, particularly the GI manifestation ones, that you give them their elimination diet—this is actually some follow-up from that elemental study that Alison Manchester performed at Colorado State. We’re still following these dogs. She’s still keeping in contact with the owners. They went on that diet. They improved. They came off the diet and transitioned back to a wellness diet. They’re still fine. It was like hitting a reset button for them. I probably shouldn’t even share that. I have no idea why. It just shows that there’s something odd, funky, about their immune system. It just shows that we don’t know everything. For example, why does it take some dogs up to 2 weeks for some dogs to flare. Why don’t they flare right away? That speaks to your memory cells. That’s your immune system. But does it really take them 14 days to flare? That’s weird. I can say that successfully, yes, food can manage them for life. Can I say that you can switch back? I’d like to say no to be black and white about it. I think the safest thing to do is stay on a therapeutic diet, but there are dogs out there that have gone back to a wellness or over the counter diet that have done well. It’s weird. Sorry I don’t have any exact answers. 

NE [24:55] No, I think that kind of is the perfect note to end things on. There is still so much out there to learn. 

JG [25:02] To investigate. Yeah. Maybe we’ll answer the question in a few years.

NE [25:05] Exactly. We’re going to have to have a follow-up webinar all about that and see how science has taken twists and turns since then. I actually think that’s a perfect note to end things on. Thank you so much for hosting this presentation for us, and for being here. I have learned so much. I’m sure all of our viewers have learned so much about this topic. Clearly, there is still a lot that we have to cover and can cover in the future. I can’t thank you enough for taking the time to do this for our community. 

JG [25:33] Thank you. I appreciate the opportunity. It’s always a pleasure to connect with everyone, so thank you. 

NE [25:39] Of course. Thank you to everyone who is here, who has listened to this presentation and asked such wonderful questions. Again, if you’re not yet a member of our community, we would absolutely love to have you join us at gooddog.com/join, so you can stay up to date on all of our future webinars and events. Because everyone is here and this is such a great audience, I will give you a sneak preview that we’re doing another webinar with Purina later in July—all about epilepsy. If that interests you, please keep an eye out for an invitation for that when we announce the exact date. But we have many more canine health education webinars and opportunities to come, just like this one, so if you enjoyed this, we hope to see you there! Thank you all so much and have a wonderful rest of the day! Bye, everyone! 

JG [26:21] Take care, everyone!