Food allergies in pets: what you should know

Food allergies in pets account for about 10% of cases seen by veterinary practices yet allergies overall make up a significant percentage of the patients we see.

Food allergies are often misunderstood. Here are some the myths we encounter as vets:

Food allergies in pets: the myths

Myth no 1: Dogs are allergic to brands of food

Dogs are not allergic to brands. The body cannot distinguish between brands A, B or C. It can only identify ingredients such as proteins, carbohydrates, vitamins, fats etc. The body can also identify different protein sources such as chicken, beef, lamb, and soy. Each protein is made up of amino acids, and each protein has a specific amino acid sequence that is unique to that protein source, let’s call it a signature. It is these signatures that trigger the dog’s immune system and initiates the allergic reaction.

So regardless of the brand, if brand A, B and C all use chicken, and the dog is allergic to chicken, then the dog will be allergic to all three foods. To make things more complicated, most dogs will respond to any diet change, but this will only be transient.

Myth no 2: The best way to diagnose food allergies is to use different diets until you find the right one.

Many dogs will respond to any diet change. We usually see some improvement for a few weeks until symptoms of itchiness return. So, one could try many diets before coming across that one ‘magic’ diet. And, remember, that just because a diet worked for a friend’s dog doesn’t mean it will work for yours. It can, therefore, take a very long time to discover a diet that works.

The best way to do it is to first make a conclusive diagnosis that the allergy is, in fact, caused by food. And there is only one way to do this – by utilising a hydrolysed diet. The use of hydrolysed diets has dramatically changed the way we diagnose and treat food allergies.

How it works: Proteins are bombarded with water molecules, breaking them up into smaller bits. In this way the ‘signatures’ are destroyed. If the signatures are not there, the immune system is not activated, thus symptoms will not occur. It is really that simple. There are no harsh chemicals used – just water.

The hydrolysed diet should be fed for 2 months. If symptoms of allergy reduce or abate, a positive diagnosis of food allergy can be made. If there is no response to a hydrolysed diet in 3 months, one can safely conclude that the patient does not have food allergies.

When trying a hydrolysed diet it is essential that only THAT food is used.  No other foods, treats, snacks or even supplements can be given. If a patient gets one bit of protein that is not hydrolysed, you are back to square one and must start the hydrolysed diet again for two months before any conclusions can be made.

Food allergies in pets: how do I treat them?

After a diagnosis of food allergy has been made, there are two treatment options.

One can continue feeding the hydrolysed diets. In some allergic dogs this is the only way to keep the allergy symptoms at bay. These diets are well balanced, good quality diets so they can be fed long-term. The only downside is that your bank account will not like this. However, it is much better than using lots of medication that does not always work optimally, or seeing your best friend scratch uncontrollably.

Alternatively, one can start challenging the allergy with various ingredients. One would start with a novel protein diet. This is a diet with a protein and carbohydrate source that is not commonly contained in pet foods. One can also add single ingredients like carrots, or apple, one at a time, trying something new every 2 weeks. If no itchiness occurs, you can continue feeding that diet or ingredient. If itchiness does return, stop immediately and know that you cannot feed that ingredient ever again. In this way a menu of possible ingredients and diets can be developed that can be fed.

What’s the deal with all the skin diets?

It has been scientifically and practically proven that food can make a huge difference to any pet that has environmental allergies (better called atopy). But it is so important to understand the role of the specific diet and to distinguish food allergies from atopy. Pets with atopy do not make a healthy fat layer that protects the skin. This fat layer is supposed to catch most of the pollens and allergens that end up on the skin, and thereby stop the immune system from being activated. By feeding specific nutrients such as omega 3 and milk hydrolyte, one can help the body produce a better barrier that reduces allergies. Additional antioxidants and good quality protein ensure a healthy skin, all reducing the symptoms. This in turn reduces the need for medication. So, even in dogs that are not allergic to food, we can use food to make a difference.


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