What is a food allergy?
A food allergy is an over-reaction of the immune system to something in the food, usually a protein. During digestion, the various components of the food are broken down, and the dog’s immune system mistakenly sees some part of the food as a threat, and an abnormally strong defensive response occurs. Over time, this response can become more aggressive and symptoms can get worse.
It’s important to distinguish a food allergy from a food intolerance, which does not involve the dog’s immune system. Intolerances are more likely to cause a gastrointestinal response, such as poor quality stool or gurgling sounds from the digestive system.
What are the symptoms of a food allergy?
Food allergies in dogs are most often expressed through the skin as itching. This may involve the entire body or be focused on a specific area, such as the ears or feet. Chronic or periodic infections of the ears or skin are common. Reactions are often located on the face, on the belly, between the toes, or under the front legs. Excessive or constant itching and biting of the affected area is common, and in severe cases, the dog is clearly in distress.
How do food allergies develop?
The latest research suggests that food allergies develop because of a condition called dysbiosis, commonly known as “leaky gut”. This can be defined as an imbalance of bacteria in the digestive system, with insufficient “friendly” bacteria and too many “bad” bacteria. With this imbalance, the intestinal lining is inflamed and weakened, and is unable to prevent undigested food particles or potentially toxic organisms from passing directly into the bloodstream. The immune system sees these as invaders and triggers a hypersensitive response. Once a particular food is classified as a threat by the immune system, it remains “on alert” and can respond in the same way for the rest of the dog’s life.
Antibiotics are most often the cause of the initial imbalance of the bacteria in the dog’s digestive system. Other drugs including vaccines, corticosteroids and non-steroidal anti-inflammatories (NSAIDS) can contribute. Highly processed diets containing a large amount of grains and food additives are also implicated.
There is thought that feeding a puppy one source of protein, say chicken, through to maturity and then forever abandoning that protein, may be a way to avoid food allergy reactions later in life. If the puppy experienced leaky gut and developed an allergic response to chicken, but never to another protein, then avoiding chicken for the rest of the dog’s life would reduce the chances of a problem.
What can you do to treat food allergies?
Curing the allergy is usually not a possibility, so you are left with dealing with the symptoms and avoiding the source of the allergic reaction. Immune suppressing drugs can be very effective in relieving itch, but their long-term side effects are severe. Topical treatments such as ointments, creams, or sprays are seldom very useful. Determining what food your dog is allergic to, and avoiding it in the future, is the preferable course of action, although it’s not always easy. Switching to a protein source that the dog has never had before, and strictly restricting the diet for a period of 8 to 10 weeks, seeing the symptoms clear up, and then reintroducing the suspect food can provide valuable information. Repeated food trials using single source proteins and simple diets are often necessary, and the guidance of someone with experience is recommended.
What is the best food for dogs with allergies?
There really is no such thing, as food allergies are a very individual thing, and what works for one dog will not necessarily work for another. But taking the time to do food trials with proteins that your dog has not previously been exposed to could go a long way towards helping your allergic dog. And we are always here to help!