Allergies Dogs May Have to Food
Food allergies are something that is difficult to identify unless one is well aware of the baseline information with regard to this type of allergy. The main symptoms of food allergies in dogs include the facial itching, limb chewing, belly itching, recurrent ear infections or skin infections.
Since the dogs consume lot of prepared food materials including various kinds of proteins, fillers, coloring agents and more; in the commercial food materials, the incidences of food allergies are more than one can imagine. Allergic reactions mostly involve the skin or the gastro intestinal tract.
If you come across your dog itching after the provision of specific food materials, then suspect the food allergy in this animal. However, conditions like fungal infections need to be ruled out in general before the conclusion of itching as a sign of food allergy.
There are many recorded incidences of allergies of dogs to corn or to wheat. However, the food allergies vary from dog to dog. Read the labels clearly before feeding your dogs with pet food materials, in such occasions. Too much colored food materials may be avoided since they may cause allergies to your dog.
Food allergies are often linked to the hyper active behavior noticed in the dogs. Added colors, preservatives, and high fat diet might cause such food allergies in the dogs and hence, one has to be careful in providing new kind of diet to their dogs and closely monitor the dog for any signs of allergy.
There are many occasions that food allergies might be diagnosed in the dogs but the dog may have other problems like pancreatitis. To rule out the food allergies, observation your dogs everytime you feed them, look for reasons to link the signs of dog with food given, specific signs encountered, differential diagnosis etc. are the important features to be given emphasis.
Now Picture this…
Your dog is itching like crazy and shaking his head constantly. Your vet just told you it could be a food allergy. What does that mean? To find out, we talked to Susan Wynn, an internationally known expert on holistic pet care. Wynn is former president of the American Holistic Veterinary Medical Association, a clinical resident in nutrition at the University of Tennessee College of Veterinary Medicine and author of four textbooks on integrative practice, focusing on dietary supplements such as nutraceuticals and herbs.
Let’s do some Q & A:
Q: How common are food allergies in dogs?
Q: What are the common signs of a food allergy?
A: Anything from chronic ear inflammation, gastrointestinal problems, and chronic diarrhea to chronic gas, licking their feet, or an itchy rear end.
Q: What are the most common things that could trigger a food allergy in my dog?
A: It’s a genetic problem, and when it’s triggered, it’s by exposure to whatever they’re allergic to. The most common allergens are beef, dairy, wheat, egg, chicken, lamb, soy, pork, rabbit, and fish. And, most dogs are usually allergic to more than one thing.
Q: What causes these allergies?
A: It’s a multi-factorial thing, but certainly you have to have a genetic predisposition to develop allergies. The environment can affect it, too.
There’s a lot of research going on right now to determine what, in early puppyhood or early kittenhood, makes the immune system more likely to express that trait. There’s an immune education process happening in the first few weeks of life. Young animals treated with antibiotics could potentially be predisposed to problems later in life because antibiotics change the environment inside the gut, which is the largest immune organ in the body. That could be a predisposing cause, but then the trigger would be being exposed to the allergen.
Q: Are some breeds more prone to food allergies?
A: There are some, but I think it depends on whom you talk to. It also can vary by country or part of the country. It may be as simple as what breeders, with their line-bred family of animals, are in your area. So if you have a very prominent breeder who is breeding a line known for their allergies, you’re going to think that breed commonly has food allergies. In my experience, retrievers, German shepherds. Dachshunds, cocker spaniels, and rex cats are the most commonly affected breeds
Q: How do I determine if my dog has food allergies, or something else is causing the problem?
A: There’s only one way to diagnose food allergies accurately, and that is an elimination diet and challenge. So what we do is take the dog off all the foods it’s eating and we put him on a food that he’s never had before. With all the exotic diets out there now, this can be pretty difficult. I’ve sent people out for alligator and yak. Once the dog has improved, we start reintroducing the old foods that we think caused the problems in the first place. If he has a reaction, which usually takes a few days to a few weeks, then we know he has a food allergy.
There’s specific testing to rule out other problems as well. For instance, you might take a sample of discharge from the ears to see if there’s a problem there, or do skin testing for environmental allergies. Blood testing is not an accurate test for any allergy.
Q: Will changing my dog’s diet trigger a food allergy?
A: If the dog has been sensitized to something in that diet it could. There’s no way of knowing if your dog has been sensitized to an ingredient, though.
Q: Can my dog suddenly develop a food allergy to something that he’s eaten for years with no problems? Will this keep happening?
A: That’s common in food-allergic dogs. They have to be sensitized; they have to have been exposed for some period of time. So, in general, they’re not going to react really dramatically the first time they eat it but a dog that has eaten a food for years could suddenly become allergic to that food.
If an elimination diet improves the pet’s clinical signs and the owner is able to find two to three diets the dog can tolerate, I recommend rotating through them every two to three months. The whole point is to keep them stable for a period of months to years so you can eventually do their challenge testing to identify what the dog is really allergic to. If you’re really lucky, then you can go back to a more normal diet and not these expensive, exotic diets. And if they’re young enough, food allergies sometimes do resolve themselves.
Q: How do I treat a dog with food allergies?
A: You can try to cover up the signs, but if you’ve got a disease that’s caused by what you put in your mouth every day, the best treatment is to stop putting that in your mouth every day. I use herbs all the time, and I do think they can help, but not as much as avoiding what’s causing the problem.
Q: Should I cook for my dog, rather than buy her food? What about a raw diet, will that help?
A: The upside of a cooked diet is you know exactly what’s going in it and you can control that. The disadvantage is it’s more trouble and, unfortunately, most people won’t do it right. They will leave off supplements, they won’t follow instructions, and they’ll end up giving their dog or cat an unbalanced diet.
There’s nothing magical about raw diets. Some dogs do very well on them and some dogs do not do very well on them. The protein structure might be different from that in a cooked or processed diet and that does make a difference for some dogs. But it’s not common enough that we need to tell everybody they should try a raw diet.
Q: Is there anything I can do to keep my puppy from developing food allergies?
A: I don’t think anyone is going to tell you that you can prevent food allergies if your puppy is predisposed. My opinion is that if you provide a diet that has some variety in it, so they’re getting a natural rotation, you’re maintaining gut health by doing that.
I do recommend for young puppies and kittens that people put them on probiotics. I’m very concerned about the use of antibiotics in growing animals. I think it messes up their gut balance and I think it may make them more likely to become allergic over time. So for puppies, I try to avoid antibiotics and use probiotics up to six months to one year of age and give them a diet that’s fairly high in variety.
Now that we got that out of the way, Let’s Dive in…
Food allergies are the over-response of your dog’s immune system to an invading protein. In the case of a food allergy, this protein is contained in your dog’s food. Proteins are present in most of the foods your dog eats. While most people recognize that meats are a source of proteins, there are also proteins present in grains and vegetables. Any one of these proteins has the potential to cause a food allergy.
Your dog’s gastrointestinal system (mouth, stomach, intestines) protects her from potential allergens each day. Approximately 70 percent of the body’s entire immune system is centered in the gastrointestinal tract. When your dog eats a meal, the food is first digested in the stomach. The large pieces of food are broken down into smaller pieces by stomach acid and then enzymes and stomach acid work together to break the complex protein structures down into smaller structures.
The partially digested food then moves into the small intestine. The food is further digested until the proteins are broken down into their smallest parts, amino acids, which can then be absorbed into the body through special cells called enterocytes. Enterocytes act as both a welcoming hostess to amino acids that they like and want, and as bouncers (door guards) for amino acids they don’t like. When a whole protein is absorbed in the intestines instead of being broken down first, the immune system reacts and your dog shows symptoms of a food allergy.
When the System Works
The intestinal tract’s ability to prevent the absorption of whole protein is dependant on the health and integrity of the mucosal barrier. It is the proverbial guardian of the body at the gastrointestinal gate. The mucosal barrier (lining of the gut) is comprised of both structural components and immune system components. The structural components physically prevent the absorption of large proteins. The immune system component is responsible for recognizing potentially harmful contents of the gastrointestinal tract. The health and integrity of the gastrointestinal tract is dependant on the normal structure and function of the enterocytes, effective protein digestion, and the presence of the dog’s immune cells (called IgA cells) in the gastrointestinal tract.
The Gut and Immune System Together Prevent Food Allergies
IgA cells are a type of immune cell secreted in the intestine. Some of the IgA will float freely in the contents of the intestine while other IgA attaches to the wall of the intestine to prevent whole protein from coming in contact with the enterocytes. Just like volleyball players they bounce whole proteins back into the contents of the intestine for more digestion. The more effective protein digestion in the stomach and intestine is, the smaller the proteins are when they come in contact with the IgA. Small proteins and single amino acids do not get bound to the IgA and are allowed to pass by the IgA and be absorbed into the body as nutrients.
When the System Fails
Malnutrition can affect enterocyte structure and function. A poorly functioning or damaged enterocyte can let whole proteins into the body. Once a whole protein has managed to breach all of the gut’s defenses, gut-associated lymphoid tissue (GALT) takes over. GALT can prevent the body’s natural immune response to a foreign protein. Most of the time this is what happens, but in the case of food allergies, GALT does not prevent the immune response and an allergic response (immune hypersensitivity) is formed.
Unfortunately, every time the food is eaten, this over-response of the immune response becomes greater. So continuing to consume the diet that caused the allergic response results in a greater and greater response every time. After this hypersensitivity is formed, each time the dog eats the food, mast cells in the body’s immune system release hertamine. If this hertamine release is large enough, it may manifest as diarrhea, itchy skin, chronic skin infections etc.
Isolating the Problem
The first thing you need to do is work with your veterinarian to make sure that your dog’s symptoms truly indicate a food allergy. If that’s the case, your vet will likely recommend that you try an elimination diet— feeding a food that has a different protein (meat) source and a different carbohydrate (grain) source than what your dog has had before. Common anti-allergy foods (novel protein sources) include kangaroo and oatmeal or venison and potato. This prevents the immune response from continuing to be triggered.
Your vet may also suggest that you try a hypoallergenic diet. These foods are made with hydrolyzed proteins. That means that the proteins are already broken down into pieces that are small enough that IgA won’t bind to them and they won’t trigger an immune response.
Lamb and rice foods used to be considered “hypoallergenic” when most commercial dog foods were made with chicken or beef and corn or wheat. Since most dogs had never had lamb or rice before, it was a good option for dogs that experienced allergies while eating a regular food. Now, however, many dogs are showing allergies to lamb and rice diets. This is to be expected since an allergy can develop to any diet. If your dog is allergic to lamb and rice you may need to find a food with different ingredients such as fish and oatmeal, or venison and sweet potato.
While your dog is on any special diet, it’s very important that she doesn’t get any other food such as cookies, treats, rawhides, people foods, etc. Since you don’t know yet exactly what she is allergic to, you don’t want to give her something other than her food and trigger the allergic reaction. Once you’ve got her on a food that she is not reacting to, you can start to reintroduce other foods. If your dog reacts, you’ll know exactly which food (or foods) causes the problem.
Preventing Food Allergies
Is there anything we, as owners, can do to avoid food allergies from developing? This is one of the toughest questions in dog nutrition today. While we still don’t really know how to prevent allergies entirely, there are things you can do that may help.
Promote a healthy mucosal barrier. This can be done by ensuring that our dogs, and especially puppies, have adequate nutrition and health care.
Watch out for gastroenteritis. There have been some theories that early gastroenteritis can be common in puppies or younger dogs. It is also thought that this can result in an adult dog that is more likely to develop food allergies. Preventing gastroenteritis, in theory, is easy— just don’t let your dog eat anything but dog food and treats. In actuality, this is much harder to deal with. Dogs eat a variety of things, some that are not harmful—grass, dirt, bark, wild berries (i.e., raspberries, strawberries). Dogs also sometimes eat a little cow or horse dung—and rotten garbage or dead animals. Neither are good for them. It can be very hard to police what goes in your dog’s mouth.
If you suspect that your dog has gotten into garbage or eaten something that may cause tummy upset, it may be best to feed your dog a low-protein diet (boiled white rice or potato) until the suspected tummy upset passes or you consult your vet. In general, if diarrhea lasts more than 72 hours without signs of getting better or if the diarrhea seems especially severe or malodorous, you should consult your vet. In these cases, do not attempt to treat the dog yourself with over-the-counter medications because diarrhea is the body getting rid of bad things in the gut. To give something that stops the diarrhea can result in keeping the bad things in the gut and causing a serious illness.
Promote effective protein digestion. In general, your dog should have no problem digesting protein. If you are feeding a homemade cooked or raw diet that’s a good thing. Grinding or blending your protein source in a food processor can be helpful in improving protein digestion. In kibble-fed dogs, the protein is already ground before it is kibbled so there is no need to grind it.
Choose a dog food with exclusive protein sources. A food that only has one or two protein sources can be helpful in giving you more choices later on should your dog develop an allergy. For example, if you use a food with five protein sources (i.e., turkey, chicken, duck, salmon, and tuna) and your dog develops an allergy to it, you now have to find a food that doesn’t contain any of these protein sources. This can be challenging. Conversely, if you feed a diet with chicken as its sole protein source and your dog develops an allergy to it, you can easily find a diet that doesn’t contain chicken.
Preventing food allergies may be impossible in dogs that are prone to developing food allergies. Some breeds are becoming noted for food allergies (see sidebar p.82). As a result, it is possible that a propensity for developing food allergies may be genetic. In that case, we should avoid breeding dogs that have food allergies.
Some Extra Special Additional Information
Some of the breeds most prone to food allergies include:
- Cocker Spaniel
- Springer Spaniel
- Collie, Dalmatian
- German Shepherd
- Lhasa Apso
- Miniature Schnauzer
- Shar Pei
- Soft-Coated Wheaten Terrier
- West Highland White Terrier
Most common food allergens include:
Least common food allergens are:
General signs and symptoms of allergies include:
- dry itchy skin
- excessive scratching or licking
- bald patches
- a high frequency of hot spots
- ear infections
- skin infections
By all means do not give up….
Dealing with a dog with food allergies can be challenging and disheartening. Proper diagnosis of food allergies can make it easier for both you and your dog. The ability to understan why food allergies start can help us prevent future allergies from starting. On a personal note, my Shepherd has had food allergies all his 9 years. It has been a long road and often a difficult one. It is so much easier to find novel protein sources now than it was 9 years ago. If you have a dog with allergies, take heart, it will get better.