Around 5 – 10% of dogs suffer from food intolerance, mirroring the trend amongst people estimated at 40-45% of the population. Contrary to popular belief, food intolerance is likely to be associated with the food that is most commonly eaten.
Pets are most often allergic to wheat (e.g. biscuits) and beef; other common allergens include pork, chicken, milk, maize, soya and fish
Recognising dietary intolerance is difficult as recurring signs are often passed off as minor illnesses such as eczema, dermatitis, vomiting, diarrhoea and lethargy, all of which can be difficult to attribute to diet alone as this can be caused by so many other disease processes.
Your vet will go through the rule-out process which might include a physical examination and laboratory tests for flea allergy dermatitis, the most common cause of allergic skin disease of animals, inhalant allergies, seasonal reactions to pollen, dust mites, and food caused digestive intolerance.
If the food allergy remains a suspect, your veterinarian will then help you try to pinpoint what might be causing your pet’s problems. Most food-allergic dogs are hypersensitive to only one or two ingredients, with beef and dairy proteins topping the culprit list. Ingredients that may also cause problems – but not as often – include grains, pork, chicken, eggs, and fish.
Once diagnosed, healing the problem can be difficult and easily made worse because of a lack of legislation governing pet food labelling, meaning dog owners cannot always clearly identify what they are feeding their pets. Pet food manufacturers are currently not obligated to name actual ingredients and some pet food labels use general terms such as ‘meat by-products’ and ‘cereal or animal derivatives’.
To definitely diagnose food allergies, most veterinarians recommend a trial with an elimination diet – a diet that contains a protein and carbohydrate source the animal has never been exposed to, followed by a gradual re-introduction of certain food types to find out the particular ingredient they are intolerant to.
The Elimination Diet
The elimination diet is the only sure way to figure out whether the problem is food related and/or what is causing it. An elimination diet includes a bland diet of white rice and a single source of protein like chicken, lamb or fish. All other foods, including treats and tit-bits must be eliminated temporarily from your dog’s diet.
The diagnosis is conclusively proven by reproducing the symptoms by gradually re-introducing the original diet after the elimination of signs from being on the new diet. Your dog can then be fed on a diet he/she will not have adverse reactions to. Unfortunately, this is not a quick process and the elimination diet needs to be persevered with until signs of the issue have disappeared.