Dear Julie,

A friend of mine recently told me that the food I’m feeding my dog could be the cause for some of the sudden aggression we have been seeing from him lately.  Does diet really effect personality and behaviour?


Nutritionally Concerned

Dear Nutritionally Concerned,

Well there is still a lot of debate on this topic, so unfortunately the answer isn’t as cut and dry as yes or no.  Definitely we know that lower quality foods contain a lot of animal by products, additives, cereal fillers and preservatives.  This provides the dog with inadequate nutrition which can lead to the development of health issues.  One of the most prevalent symptoms of a medical condition is behaviour changes, including aggression, so in this case yes, a poor diet can be attributed to behaviour changes.  In addition, many low quality foods also contain chemical additives to keep the food moist, and to add colour, which some dogs may have an adverse reaction to, causing a behaviour change.  Not to mention, just imagine how you would feel if you ate fast food for every meal of your life.  At first you may love it, but eventually that kind of diet would take a toll on you physically and mentally.

The other school of thought is that foods that contain high levels of protein cause a deficiency of the serotonin levels in the brain.  Serotonin is the neurotransmitter (chemical messenger) in the brain that is responsible for many things, including regulating mood and pain levels.  Low serotonin levels can be linked to issues such as; learning impairment, anxiety, aggression, obsession and reduced impulse control.  Now the validity of this school of thought is still being explored and further research is required. However, in my own practice, I have found that many of my aggression cases that where on high protein diets and switched to a diet richer in carbohydrates, made mild to moderate improvements after they reached a plateau in their program.  This means, once the dog had stopped making progress and was unable to be moved on to their next stage of rehabilitation, a change in their diet caused enough of an improvement that we where able to resume their program.

What it all boils down to, is that your veterinarian is your best source for nutrition information. If you have a concern regarding sudden behaviour changes in your animals, your veterinarian is also the best person to help you uncover the root cause.