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Food Allergies in Dogs: Understand how to effectively unlock the puzzle

A veterinarian walks you through understanding, and diagnosing food allergies in dogs. Food sensitivities in pets are more common than most people think and ruling them in or out is complicated.

Highlights :
1) It makes no difference if your dog has eaten the same food for the last 10 years. That does NOT stop them from developing food allergies or sensitivities over time.
2) The animal protein source tends to be the allergen. Less commonly the carbohydrate sources can be the problem. Rarely do fats or oils (animal or soybean) cause an issue.
3) Most common food allergens in pets are : beef, wheat, corn, chicken, dairy (milk, cheese, ice cream), egg, and soy. Beef, wheat and corn are the most common. (These are not ‘bad’ ingredients, they are only ‘bad’ if the individual animal in question is allergic or sensitive to them).

If there has been a history of multiple diets in the past, then you try to avoid any animal protein source that they have already been exposed to. Aim to choose a new single protein source, and a new single carb source they have not been exposed to before.

Bear in mind that lamb and chicken are no longer consider as novel or hypoallergenic as they used to be because they became such a common addition to many diets. Also realize that some dogs that have beef allergies will, over time, cross react to lamb and venison as well (possibly any ‘red meat’ over time).

Protein sources currently considered reasonably hypoallergenic: ostrich, goat, rabbit, venison (red meat – avoid for beef allergy suspects), buffalo (red meat = avoid for beef allergy suspects), kangaroo, fish and duck. Carb sources considered hypoallergenic: potato, sweet potato, cassava, millet, peas, beans. Dogs with suspect or known wheat allergies may also commonly react to rye and barley.

Not all “sensitive skin” diets are acceptable for a trial rule out diet as many actually contain corn and/or wheat. Many sensitive skin diets simply have more added omega 3’s (which is great for skin issues) but are NOT restrictive with their protein and grain contents, which is what we are looking for in a food trial diet choice.

Correct Principles of a Proper Food Trial
1) NOTHING in the dog’s mouth except the chosen food and water for 3 months. NO treats and NO table scraps. This includes chew toys (rawhide = beef), pig ears, dental treats, and flavored plastic chews. Even small amounts can ruin the effort entirely.
2) There is NO earthly way to magically divine what is and is not a problem for the pet without a food trial. Not unless you can read a crystal ball (and if you can then I need to hire you so we can both get rich).
3) Understand it takes a month or more to work the current problem proteins out of the pet’s system after a diet change.
4) Avoid ALL else for 3 months. THEN, if you have a good result and the pet has improved, you can begin to feed back single ingredients for 5 days at a time and see if any itching and irritation develops. This will allow you to know exactly what ingredients to avoid. This should allow you to have a wider range of commercial foods to choose from.
5) If there has been a definite positive response to the food trial, then from this point onward (yes = for life), ANY new food or treat that you wish to try to transition to after the trial should be added one at a time. That allows you to verify that no problems arise within a week of a new food addition. If there is no problem with the addition or change after 5-7 days then all is well. If signs of allergy return within 5-7 days of a new diet addition then compare the main ingredient listings to see IF you can tell what was likely the problem.
6) You cannot trust the ingredient content listing in average commercial diets and treats. They are NOT required to have them tested, nor are they required to clean their machinery in between batches of this food/treat and that food/treat. Some places do, but many do not. Some have zero control over the manufacturing plant that bags their food!! Do the best you can, but always be wary. Blue Buffalo was successfully sued over their dog foods lacking oversight and having nearly no relationship to the actual ingredient listing on the bags. But it is a generally large problem in the entire industry which makes food trials even more difficult.

Legitimate Treats :
1) Almond Butter or Cashew butter can be used (No peanut butter or cheese especially if they have ever had that previously)
2) Pieces of the actual protein (only) in the chosen diet. Jerkies are acceptable. Or cut up canned chunks of the protein chosen and freeze, bake, or microwave it.
3) Venison jerky (if not beef problem suspicious), or rabbit jerky
4) Deer antlers or elk antlers for chew toys
5) Pieces of the actual carbohydrate source in the chosen diet – potato, sweet potato, rice cakes. Check rice cakes to be CERTAIN they have no corn or wheat additives listed.
6) Apples (dried chips), bananas (dried chips), melons, broccoli, baby carrots, green beans.
7) Simple trick : Use the kibble from the chosen trial food as a treat. Most dogs are easily fooled, especially if you put the kibble into a separate container from the dog food, and place it wherever it is that you usually store the treats. If it comes from the ‘treat spot’ and a ‘treat container’ then most of the time they are perfectly happy to have a bite of their kibble for a treat.

Some Acceptable food trial diets to consider :
I no longer have an up to date version of known functional diets. It has been a decade since I routinely advised. Check with your vet, but even then, pay close attention to the ingredient listings. Manufacturers are NOT required to notify when they change diet ingredients and formulations due to changing cost of bulk ingredients. Some do so but none are required to.

I do not care for hydrolyzed diets personally because I found that many dogs that were corn allergic remained reactive on those diets, so I do not consider them adequate food elimination trial diets. My recent opinions on that have not changed.

In the past – the following brands were known for excellent manufacturing facility controls and so seldom had cross contaminating allergens in their food allergy geared diets: Royal Canin limited ingredient prescription diets, Hill’s prescription diets, Purina Proplan lines, and Natural Balance limited ingredient lines. RC tend to be most expensive but very good for trials, Hill’s feline diets are better than their canine choices (they still often contain wheat and corn depending on the type). Purina Proplan canine salmon sensitive skin USED to be good, Proplan feline seafood diets had some good choices as well, but I have heard they may have changed their formulas to include wheat or corn now – check the bag/can labels. Natural Balance changed hands years ago and I cannot report on how they are now. Costco actually used to have a great salmon based diet that had none of the usual allergens and was very affordable – but you would need to check it too.

There is a difference between diets that may be acceptable to eat AFTER a trial and diets that are acceptable to use FOR a trial. The trial diets must be as free of allergic contaminant ingredients AND listed allergic ingredients as possible. A great many routine diets/treats which claim to be free of this and that are produced on machine lines where there is no sterile wash between batches of entirely different foods.

Small amounts in such contamination between batches may not be a problem for most food allergic dogs, but it can ruin a trial for some of the more severely allergic animals. So the short story is, do NOT scrimp on the trial diet or substitute blindly with a food that has not been shown to be free reliably allergen free in production. If the trial proves the animal to have a sensitivity or allergy, you need remain hyper aware of trying new food carefully and slowly and with great suspicion for backwards steps in allergy control.