Dogs behaving badly: does nutrition have a role to play?

Veterinary professionals are increasingly embracing a holistic approach to animal care. A rise in behavioral issues post-pandemic has therefore driven interest among the vet community in the impact of nutrition on behavior and the potential part it may have in treating such issues in dogs.

The pandemic puppy effect

The COVID-19 pandemic had a profound impact on the behavior of many dogs, including the infamous cohort of ‘pandemic puppies’ (puppies acquired during lockdown). The sudden and drastic change in routine coupled with a lack of socialization opportunities led to behavioral issues in a great number of pet dogs.

A lack of exposure to everyday experiences has led to a marked increase in separation anxiety and a fear of new people, places or other dogs. This in turn has led to an increase in behavioral problems, since these dogs cope by either becoming fearful and withdrawn, or reactive.

In 2020, the UK’s Royal Veterinary College conducted a study involving more than 1,000 dog owners. The study, published in the journal Animals in March 2022, looked at owner-reported behavioral problems. Some 97% of owners reported their dog displayed at least one of the behavioral problems listed and 31% reported separation anxiety-related behaviors.

Linking nutrition and behavior

While further research is needed, recent literature reviews of studies to date indicate diet could well play an important role in the adjunctive treatment of behavioral concerns in dogs.

L-tryptophan

Behavior is regulated by hormones and neurotransmitters, such as serotonin (the ‘happy hormone’). Serotonin helps to reduce aggression and anxiety, and promotes positive behavioral responses. L-tryptophan is the precursor to serotonin.

The composition of a diet, alongside bioavailability, can affect the availability of precursors such as L-tryptophan in the brain. It follows that a diet that facilitates healthy L-tryptophan levels could therefore be beneficial for dogs with behavioral problems. In fact, there are already products on the market with this as their USP.

A study by researchers at Tufts University in Boston, and published in the Journal of the American Veterinary Medical Association (AVMA) in 2000, demonstrated that for dogs with dominance aggression, the addition of tryptophan to high-protein diets (or change to a low-protein diet) may reduce aggression. Numerous other studies have also demonstrated the role of these compounds in influencing animal behavior.

Polyunsaturated fatty acids (PUFAs)

PUFAs, in particular docosahexaenoic acid (DHA), are important in brain development. Dietary supplementation with PUFAs could modify certain aspects of the serotonin pathways, therefore influencing both behavior and cognitive performance, as has been observed in rodents.

One study from researchers at Italy’s University of Pavia, published in Veterinary Research Communications in 2008, suggested that low omega-3 fatty acids may negatively affect behavior in dogs, making them more prone to aggression.

However, the authors stipulate that further studies are needed to determine whether supplementation could help reduce aggressive behavior in dogs.

Dietary fiber

Dogs that are motivated by the thought of their next meal between feeding times can show increased unwanted behaviors. Some dietary fibers have been shown to prolong satiety, thus reducing hunger between meals. This may be beneficial for dogs with hunger-driven behavioral issues.

Medium-chain triglycerides (MCTs)

While the role of MCTs in dogs with behavioral problems needs researching, we already know that MCTs are beneficial to overall brain health. A diet rich in MCTs can help dogs with cognitive dysfunction, such as might come with aging.

This is possibly due to improvement in energy metabolism in the nervous system. Dogs with cognitive dysfunction syndrome (CDS) have impaired glucose metabolism.

A diet rich in MCTs causes ketone bodies to reach the brain, where they are used as an alternative energy source by neurons, improving their function. Dietary MCTs can also increase the levels of n-3 fatty acids in the brain, which are structurally important for neurons.

Synergistic ingredients

One study from a joint Italian and American research team looked at serotonin and dopamine as behavioral markers, and cortisol and norepinephrine as stress markers, in dogs with behavioral disorders.

The 45-day study, published in the Veterinary Record in 2016, assessed the effects of a diet containing L-tryptophan and PUFAs alongside other ingredients, such as green tea extract.

In dogs who were fed the diet, serotonin and dopamine significantly increased, while cortisol and norepinephrine decreased.

In another study, published in the British Journal of Nutrition in 2018, researchers from the US and Canada supplemented elderly dogs with a ‘brain protection blend’ consisting of fish oil, L-arginine, antioxidants and B vitamins.

The supplemented group showed significantly better performance in specific learning tasks. The study concluded that long-term supplementation with this blend of nutrients can improve cognitive function.

Intriguing area of development

Every year, millions of dogs are rehomed, abandoned or euthanized due to behavioral issues.

There is emerging interest within the veterinary community in the role nutrition plays in behavioral issues in dogs – not only focusing on how poor nutrition may contribute to unwanted behaviors, but also the role nutrition can play in the management of behavioral problems.

There are currently a very limited number of dog foods available that are marketed to support brain health and improve behavior, exposing a potential gap in the market.

Extensive further research in this exciting area of nutrition is required to identify both optimal and safe dietary inclusion levels, alongside further research on the exact effects on behavioral issues.

While, naturally, nutrition cannot replace behavioral therapy from a qualified, certified behaviorist, it may well be beneficial alongside therapy.