For many dog owners, the idea of their dog ever being aggressive is laughable. They have what amounts to a living teddy bear that loves to chase sticks and go on long walks. That idyllic picture isn't always the case for the rest of us. Aggression is a very real hurdle for some dog owners. For some owners, aggression comes out at the sight of the mailman or any other strange passersby. For others, resources guarding brings it out. Whatever the reason for your dog's aggression, there *could* (more on this hesitation later) be a diet solution that you should talk to your vet about adding to your desensitization therapy.
Every dog has a threshold for aggression. When that threshold is met or surpassed is when they act on it. For the teddy bear dogs, that threshold is quite high and unlikely to ever be met. For other dogs, including my own, that threshold isn't so high, especially in particular situations. While those thresholds and situations may vary widely from dog to dog, there have been studies that show a particular commonality - low amounts of serotonin.
Serotonin is an important neurotransmitter (a compound that sends signals from nerve to nerve) that for the purposes of this article can affect mood and social behavior (among other things). The link between low levels of serotonin and aggression implies that serotonin can have a major part in regulating a dog's threshold for aggression. So how can we ensure a healthy amount of serotonin in our pets?
The answer is kinda tryptophan. I say kinda because it isn't as easy as just feeding your animal a bunch of turkey and hoping they stop lunging at the mailman. Here's why:
Tryptophan is an amino acid, the things that make up proteins. It's commonly found in poultry and other meats and is a precursor, or building block, of serotonin. Our bodies can't produce it so we have to get it from our diets, but like I said, it isn't enough to just feed our pets a bunch of turkey.
The current trend in pet food is a focus on high amounts of quality proteins while limiting carbs from grains. This focus can actually make it so that our pets are getting less tryptophan to make into serotonin. This is because the conversion of tryptophan to serotonin relies on enough tryptophan getting through the blood-brain barrier. When there are a bunch of other amino acids competing to get across, tryptophan is often the one left behind. Today's diets also focus on being low carb, but carbohydrates help tryptophan cross the blood-brain barrier in larger amounts.
An anti-aggression diet or serotonin boosting diet is one that focuses on being high carb and low protein. Not so much low as focused, rather. There is a prescription diet by Royal Canin (they aren't paying me to tell you about this, but they should!) called CALM that uses this idea. One study showed reduced stress responses in dogs and cats during nail trims.
Could this diet work for your pet? It depends. The research I'm referencing seems to point to this kind of diet only working for dogs and cats that are territorially aggressive, but the study done on the CALM diet seems to show that this diet can help to reduce the overall stress response, where serotonin is not directly related.
If your pet struggles with aggression issues and they're only getting so far with desensitization training, talk to your vet about possibly shifting their diet. Don't try to take their diet into your own hands! Your vet will either prescribe the CALM diet or one like it or will give you a well-balanced recipe. It's important that you keep up or start desensitization training to help them raise their aggression threshold. This is still the best way to overcome aggression issues. As always, be patient and good luck!