Petfood can obviously affect the health of pets, but it may affect more than that. Petfood ingredients, for example, might affect pet behavior, according to some studies.

The fatty acid DHA (docosahexaeonic acid), sometimes added to puppy and kitten food, has been shown to increase mental acuity in puppies and kittens, according to Dr. Lorie Huston, DVM, a small animal veterinarian in Rhode Island. Puppies eating dog food with DHA may also be more trainable.

Certain antioxidants have been found to be beneficial to senior pets in terms of cognitive maintenance. A series of studies conducted on dogs found that older dogs provided with an antioxidant-rich diet were able to learn complex tasks with more success than those on a control diet. Another study used an antioxidant-rich diet and found that older dogs were less likely to suffer from age-related behavior changes associated with cognitive decline. Dogs on this diet were also able to recognize family members more easily and retained more agility than the control group.

Petfood can affect other areas of a pet's life, as well, through feeding times and unbalanced diets, both of which can play significant roles in a pet's mood and behavior, according to experts.