FOOD ALLERGIES and ELIMINATION DIETS
I decided to write this article as I have recently received so many requests (should I say “pleas”) for help from people whose dogs are experiencing severe allergy symptoms . Please note that I am not a medical professional and provide this information from experience with my own and foster dogs, from my own research and from information from my own vets. You should test my advice by doing research of your own and checking with your own canine medical professionals. Just be forewarned that many vets, including some dermatologists, deny the connection between allergies/ “atopy” and food intolerance and have a vested interest in promoting diets they stock in their clinics. It is helpful to understand that nutrition is an extremely small component of vet training and is often sponsored by certain kibble manufacturers. If the vet has not taken post-graduate studies in nutrition, their knowledge may not be as reliable as you would expect. In fact, some of them “don’t know what they don’t know”. So it is up to you to ensure that you are getting proper nutrition counsel.
To provide a simplified explanation, a food allergy is the manifestation of the dog’s immune system creating antibodies acting against the offending food, just like a vaccination creates antibodies to fight a disease. When the dog eats the offending food from then on, the antibodies bind to the protein in the food and cause histamines to be released from the mast cells and basophils. This process sets up an inflammatory response that shows up as itchy spots, ear infections, etc. The immune system is over-reacting, literally treating the food as an invader and fighting it.
You need to identify which ingredients are the culprits for your particular dog. Unfortunately lab tests (e.g. patch tests) are not nearly reliable enough at identifying food allergens. There is too great an incidence of false-positive and false-negative results and a very real risk of cross-contamination of foods in the manufacturing process. However, patch tests are fine for identifying environmental allergens. Often a dog will have allergies to both food and environmental allergens and it is useful to know this since allergies are cumulative. For instance, a dog may have an allergy to, say, beef, but does not manifest symptoms most of the year. But if that dog is also allergic to leaf mold, it will begin scratching like mad in early spring and late fall. At those times, when they are exposed to leaf mold, they have surpassed their “itch threshold” and you might think they have only seasonal allergies. But the true culprit may be the food.
In my experience, grains (especially wheat and corn) are the most common food allergens for dogs. So my first piece of advice is to remove all grains from the dog’s meals and treats. While this usually rectifies the problem, sometimes the symptoms persist and we have to look at other foods as the potential culprits. Dogs, like humans, can be allergic to all kinds of food from some meat/poultry to certain vegetables to additives . “Food allergies cause a lot of harmful reactions, including swelling of thyroid glands. When eaten raw, cruciferous foods such as broccoli, cauliflower, spinach and asparagus are major allergy factors in thyroid inflammation, as they contain a natural chemical known as goitrogens, which is a goiter producer” . This is when trying a food elimination diet becomes useful. Studies have shown that beef and dairy products (including cheese) are high potential allergens. To a lesser extent, chicken, eggs, soy and additives (dyes, preservatives) should also be checked. Oftentimes, allergic dogs are switched to fish-based kibbles, or specialty foods such as “venison and potato” because they are “novel proteins”, i.e. foods the dog has not been previously exposed to and therefore has not developed an allergy to.
Often a vet will advise the inclusion of an oil to the atopic dog’s diet. But we must be careful what oils we use – whether they are high in omega-3 or omega-6 essential fatty acids (EFAs). When the dog consumes EFAs, its body produces certain prostaglandin hormones. From consumption of omega-6 EFAs, the body produces the prostaglandin which increases the immune system’s response. Since the immune system is already over-reacting to the “invader”, this will aggravate the allergy systems. On the other hand, consuming omega-3 EFAs dampens the immune system’s response. A balance is required.
I personally prefer coconut oil to any other oil. Fish and vegetable oils contain long-chain polyunsaturated fatty acids that are prone to oxidization in the body and use up vitamin E to prevent that. Coconut oil, on the other hand, is a saturated fat consisting of short and medium-chain fatty acids which actually enhance the absorption of vitamin E. Containing a high level of lauric acid, it has many benefits which you can read about here: Why Coconut Oil is Good For You and here: How Coconut Oil Benefits Your Dog's Health - Whole Dog Journal Article (you’ll need to order the article). I particularly like its antimicrobial and thyroid-stimulating properties.
FOOD ELIMINATION TRIAL
The basic premise behind a food elimination trial is to isolate each food in order to determine which one or more the dog is allergic to. Because of cross-contamination in the manufacturing process, kibble elimination trials, as I know from first hand experience, are not sufficiently effective for most dogs and we must go back to the original, unprocessed raw food to get a true result.
Please note that the food elimination process is not a balanced diet and so is not recommended for puppies who need a nutritionally complete diet for growth and development. Adults suffering from allergies can usually afford some temporary nutritional deficiency (e.g. imbalanced calcium:phosphorus ratio) to get to the root of their problems. It should be used with extreme caution when dealing with dogs with other health issues, including hypo- or hyperthyroidism, urine infections, etc.
Note also that the natural foods used in the trial will not necessarily be the same as their counterpart ingredients used in commercial diets. For instance, the “chicken meal” in kibble has been processed so even if the dog can tolerate raw chicken, it might not be able to tolerate the chicken-based kibble. You need to remember this if you are considering reverting to a kibble diet (even a so-called hypoallergenic diet) after the trial.
• Do not use treats other than bits of the food already tested
• Do not add supplements or vitamins until you have a stable base of safe foods
• Portions stated are for a pug weighing about 15 to 22 lbs.; most pugs over this weight could probably stand to lose a little weight.
Here’s how it works.
Go to the supermarket and buy some pork chops or a pork roast. Don't be scared off by the fact it is pork; supermarket grade pork in Canada does not carry the parasites that we have historically associated with it. (I’m suggesting pork to start off with because most dogs haven’t been exposed to it – it’s a “novel protein” – but you could substitute another meat/poultry choice instead – e .g. turkey.) Cut the raw pork up into kibble size pieces (remove the fat as much as possible) and freeze for at least 2 days in portions of about 3-4 oz. (about the size of your closed fist). Defrost a portion for every meal - one for breakfast and one for dinner. Obviously you cannot free-feed so if you are in the habit of just putting the food down and leaving it, you'll have to switch. Do this for every meal - only pork cubes for about 10 days. Nothing else. No additives, supplements, etc. Any treats should be little bits of the pork. Introduction of ANYTHING else will defeat the purpose of the trial. Evaluate if there is any improvement or not. You should notice the coat becoming softer, less scratching, no hives, etc. You may not notice an improvement in ear or eye discharge and you may even notice an increase as the body begins to detoxify.
If the symptoms persist or worsen, note pork as an allergen and stop feeding it. Switch to another protein source and repeat the process.