You have been to the vets, and they have suggested that your pet’s skin, ear or gastrointestinal problems may be caused by a food intolerance or allergy. The veterinary team may have recommended a special diet, but special diets can be difficult to find, so you grab a bag of a hypoallergenic food from the local pet shop or supermarket instead. Will it do the same job?
The short answer is no, it might not.
The term “hypoallergenic” is often used when a diet has been formulated with ingredients that the manufacturer thinks are less likely to be associated with allergies, although there are no official requirements. The difficulty is that every pet is different, and a diet that is “hypoallergenic” for one animal may contain allergens that are a problem for another.
The elimination diet trial
One reason your vets may have recommended a specific diet is to perform an elimination diet trial. This is a vital part of the investigation of your pet’s problem and is the only way that a food allergy can be diagnosed. Elimination diet trials can be challenging to perform but there is no better alternative. There is good evidence that blood tests are not reliable when it comes to dietary allergies in dogs and cats. The same is true of saliva or hair samples and skin reaction tests.
In a nutshell, an elimination diet trial involves feeding your pet a special diet that it is very unlikely he or she will be allergic to. Your vets will ask you to feed this and nothing else (most likely for 1-3 months) to see if the problem resolves. If the signs do improve, they may also ask you to feed the original diet again to see if the problem returns.
It’s important to note that these special veterinary hypoallergenic diets have features that make them suitable for elimination diet trials and may be different to regular “hypoallergenic” foods that can be found in your local supermarket or pet shop.
Not allowing your pet access to any other foods, can be surprisingly difficult. This includes bits that the kids have dropped, licking the plates in the dishwasher and anything that your
cat may hunt! You also need to be careful with any flavoured toothpastes, medications, or anything your pet ingests that isn’t plain water. There may be the opportunity to add more variety into your pet’s diet once the diet trial is over, but this should always follow a discussion with your vet.
There are several dietary approaches for an elimination diet trail:
Hydrolysed protein diets
When an animal has an allergic reaction, it is usually because the immune system recognises and inappropriately reacts to a protein that it thinks shouldn’t be there.
Hydrolysed diets can avoid this response because the proteins have been broken down
(hydrolysed) into smaller pieces that the immune system doesn’t recognise. For this reason, it is much less likely that your pet will have an allergic reaction to these diets. As an added benefit, these smaller pieces of protein (peptides) may also be easier to digest. It’s worth noting that some diets contain a mixture of hydrolysed and intact proteins. For elimination diet trials, a diet that contains only hydrolysed protein is recommended.
Some hydrolysed protein diets have other additional benefits. For example, Purina Pro Plan Veterinary Diets HA Hypoallergenic (often called Purina HA), is a complete and balanced diet suitable for long-term feeding that contains additional skin supportive nutrients such as zinc, vitamin A and omega-3 fatty acids, as well as being extremely highly digestible and
low-moderate in fat. This makes it a great choice for nutritional support of patients with a variety of skin and gastrointestinal conditions.
Producing a hydrolysed protein diet is a specialised process and steps need to be taken to minimise the risk of contamination with other proteins during the manufacturing process and
in other raw materials. You should look to purchase a proven diet produced by a reputable manufacturer with strict quality controls. You can trust the recommendation made by your veterinary practice.
Novel protein diets
For the immune system to react to a protein it needs to recognise it, and to recognise it, it must have seen it before. Therefore, if you feed a diet that contains novel proteins – proteins that the animal has not been exposed to before – an allergic reaction is less likely to occur. This is a simple enough idea, though can be difficult to achieve in practice for a couple of reasons. One is that most pets have been exposed to a wide variety of different proteins throughout their lives and to confirm that a protein is truly novel, requires an extensive and accurate dietary history. Do you remember all the foods, including treats and table scraps, your pet has eaten for his or her entire life?
The wide variety of proteins included in the diets of modern pets can severely limit potential diet options and require the procurement of increasingly unusual proteins. Another challenge is that there can be some cross-reactivity between similar proteins, for example chicken and turkey. For these reasons, a hydrolysed protein diet is often considered a more reliable choice.
An example of a diet containing proteins that are more likely to be novel is Pro Plan Veterinary Diets DRM Dermatosis for dogs. DRM contains herring, rapeseed and pea protein and is carefully formulated to support skin health.
Other
Finally, your vet may not feel that an elimination diet trial is necessary, but still recommends a special food. The most suitable diet will depend on your individual pet’s problem and any other dietary requirements they may have. Some examples are limited ingredient or “low antigen” diets with high digestibility to reduce potential stimulation of the intestinal immune system. Some diets are specially formulated with a profile of nutrients tailored to support skin or gut health – you can read more about some of the benefits of gastrointestinal diets here: Help, my pet has diarrhoea! When to worry and what to do
Your veterinary team will probably recommend a diet with a fixed formula, such as one from the Pro Plan or Pro Plan Veterinary Diets range. Foods with a fixed formula use the same ingredients in every batch so you won’t need to worry about ingredients that your pet can’t tolerate, such as certain types of meat, being present in some batches. This contrasts with open or variable formula products where manufacturers can make use of proteins that are seasonally available to lower the price of the food, meaning that each batch may contain proteins from different animals.
In summary, it’s important to follow the advice of your veterinary practice. Not only can the right diet help to support your pet’s health, but it may have been selected carefully as an important part of the investigation into their problem. If you are not able to use the recommended diet due to availability, cost, or for any other reason, always discuss this with your veterinary team. Identifying dietary allergies at an early stage can lead to a prompt improvement and support.
Thank you for Purina for contributing this paid blog.
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