The Gut–Brain Axis: How Your Dog's Food Can Support a Calmer, Healthier Mind

Your dog's gut and brain are in constant, two-way communication through a system called the gut–brain axis, and the food your dog eats is one of the most direct ways to influence it. The gut microbiome produces key neurotransmitters, including serotonin, GABA, and dopamine, that regulate mood, stress response, and behavior. When that microbiome is balanced and well-supported by diet, dogs tend to show calmer, more resilient behavior. When it is disrupted, anxiety, reactivity, and digestive upset can follow.

What your dog eats determines which bacteria thrive in their gut, what compounds those bacteria produce, and how well their gut-brain communication system functions.

Diet is not a cure for behavioral challenges, but it is one of the most powerful foundational tools available to support a dog's emotional and physical well-being.

If you’ve ever noticed your pup acting unsettled during digestive upset or becoming more relaxed when their routine and feeding are consistent, you’re not imagining it. It’s the powerful connection of the gut-brain axis at play, and it’s changing how we think about pet nutrition, behaviour, and overall wellbeing.

At Tom&Sawyer, we believe nutrition is one of the most effective ways to support this connection - starting with how food is made!

We go deeper into the science of the gut-brain axis in dogs, how the microbiome shapes behavior, and what a gently-cooked whole food diet can do to support that connection.

What Is the Gut–Brain Axis

The gut–brain axis is a two-way communication system between your pup's digestive system and their brain. Signals constantly travel back and forth, influencing:

• Mood and stress response
• Behaviour and emotional regulation
• Immune function and inflammation

A key driver of this system is the gut microbiome which is made up of trillions of microbes living in your dog's digestive tract. These microbes don't just help digest food. They also produce compounds that directly affect brain function and behaviour.

What Dog Gut Bacteria Produce and Why It Affects Behavior

Inside your pup's gut, beneficial bacteria are doing more than you might expect.

1. They produce key "feel-good" chemicals such as:

• Serotonin: linked to mood and anxiety
• GABA: a calming neurotransmitter
• Dopamine: reward and motivation

1. They create important metabolites through fermentation

• Short-chain fatty acids (SCFAs) that support gut health and even influence brain function!

1. They help regulate stress

• By interacting with the HPA axis, which controls cortisol. Cortisol is one of the body's stress hormones!

When the microbiome is balanced, it can help to support calm, adaptive behaviour. But when it's disrupted (a state called dysbiosis), it can contribute to:

• Increased anxiety or reactivity
• Inflammation
• Digestive upset
• Behavioural changes

Dog Anxiety Behaviors That May Be Rooted in Gut Health

Anxiety-related behaviours are extremely common in dogs. These types of behaviours can include:

1. Noise sensitivity or phobias
2. Reactivity or aggression towards a "trigger"
3. General fearfulness
4. Restlessness and separation anxiety

While behaviour is influenced by many factors such as genetics, the environment, training, and other factors not yet fully understood, the gut microbiome is emerging as an important piece of the puzzle.

How Your Dog's Diet Plays a Role in Behaviour

Your fur baby's diet is one of the strongest influences on their gut microbiome.

What they eat determines:

• Which bacteria thrive
• What metabolites are produced
• How resilient their gut environment is

In other words: Food plays a direct role in shaping gut health and the gut-brain axis.

How Gently-Cooked Food Supports the Gut–Brain Axis

At Tom&Sawyer, our gently-cooked meals are designed with both digestion and overall health in mind. Here's how this approach helps support the gut–brain connection:

Improved Digestibility

Gently-cooked meals use fresh, whole ingredients prepared at lower temperatures than traditional processing. At Tom&Sawyer, we go even further and cook each of our human grade ingredients individually to their optimal internal temperature to maximize nutrient bioavailability and digestibility.

This helps:

• Preserve nutrient integrity
• Make proteins and carbohydrates easier/quicker to digest
• More nutrients per bite and less left behind

A well-digested diet leaves fewer undigested materials in the gut, supporting a healthier microbial balance.

Our Turkey Gobbler Feast is a great example of this in practice. Turkey is a lean, highly digestible animal protein that places minimal digestive load on the gut, making it easier for the body to absorb nutrients fully and leave less undigested material behind for disruptive bacteria to feed on.

Supports a Diverse, Balanced Microbiome

Human grade, whole food ingredients provide:

• Natural fibres and prebiotic compounds
• Nutrients that the beneficial bacteria use to thrive

This helps encourage the growth of "good" microbes that:

• Produce beneficial SCFAs
• Contribute to gut barrier integrity
• Support immune balance

Helps Maintain Gut Barrier Function

The gut lining acts as a protective barrier. When it's compromised, inflammation and stress signals can increase.

Certain microbial metabolites (like the SCFA butyrate) help:

• Strengthen this barrier
• Reduce inflammation
• Support overall gut stability

A purposefully processed, nutrient-rich diet helps maintain this protective system.

Our Kangaroo* recipe is one of the highest fibre options in the Tom&Sawyer lineup. Dietary fibre is the primary fuel source for beneficial gut bacteria that produce short-chain fatty acids like butyrate, the very compound that helps strengthen the gut barrier and reduce the inflammation signals that travel through the gut–brain axis.

Reduces Unnecessary Stress on the Body

Gently-cooked diets focus on:

• Simple, recognizable ingredients
• Minimal processing
• Targeted nutrition

This creates a more stable internal environment compared to other food formats, supporting both gut and brain health.

Supports Emotional Wellbeing

Through its impact on:

• Neurotransmitters
• Inflammation
• Stress hormone regulation

A balanced gut microbiome can play a role in:

• Calmer behaviour
• Better stress resilience
• Improved overall wellbeing

While food isn't a "quick fix" for behavioural challenges, it's a powerful foundational support.

Our Goji Berry Beef* recipe includes goji berries, a whole food ingredient known for its antioxidant content. Antioxidants help reduce oxidative stress throughout the body, including in the gut environment, supporting the kind of balanced internal state that allows the gut–brain axis to function at its best.

The Big Picture: Nutrition and Lifestyle for Dogs

Supporting your pup's gut–brain axis isn't just about food, but nutrition is the foundation that we can build upon.

For best results, combine:

• High-quality, gently-cooked nutrition
• Regular routines
• Enrichment and exercise
• Positive behavioural support

The science behind the gut–brain axis is still evolving, especially in dogs, but one thing is clear: Gut health and brain health are deeply connected.

Which means that what you feed your pup matters more than ever!

By choosing a gently-cooked, whole-food approach, you're not just nourishing your dog's body, you're helping support their emotional wellbeing, too! Join our pack and treat your fur family to gently-cooked meals that help them live happier, healthier, longer lives™.

How Tom&Sawyer® Nourishes the Gut–Brain Connection

At Tom&Sawyer®, every recipe starts with human grade whole food ingredients, cooked gently in a federally inspected human grade facility to preserve the nutrients that matter most for your dog's gut health, immune function, and overall wellbeing.

Our meals are formulated by Dr. Hannah Godfrey, PhD, Animal Nutrition, and built on the understanding that what goes into your pup's bowl has a direct impact on how they feel, behave, and thrive. Zero preservatives, minimal additional supplementation, and whole food ingredients that support a diverse, balanced microbiome from the inside out.

Because a calmer, healthier pup starts with what's in their bowl. Sawyer's Pack knows their dogs deserve better, and that's exactly what we deliver.

* currently available in Canada only

References

• Bacque-Cazenave J, et al. 2020. Serotonin in animal cognition and behaviour. Int J Mol Sci. 21(5):1649.
• Greary EL, et al. 2022. Effects of a midly cooked human-grade dog diet on gene expression, skin and coat health measures, and fecal microbiota of healthy adult dogs. J Anim Sci, 100:1-15.
• Huo R, et al. 2017. Microbiota modulate anxiety-like behaviour and endocrine abnormalities in hypothalamic-pituatary-adrenal axis. Front Cell Infect Microbiol. 30(7):489.
• Oba PM, et al. 2020. True nutrient and amino acid digestibility of dog foods made with human-grade ingredients using the precision-fed cecectomized rooster assay. Transl Anim Sci, 4:442-451.
• Pilla R, Suchodolski JS. The role of the canine gut microbiome and metabolome in health and gastrointestinal disease. Front Vet Sci, 14(6):498.
• Sacoor C, et al. 2024. Gut-brain axis impact on canine anxiety disorders: New challenges for behavioural veterinary medicine. Vet Med Int. 2856759.
• Scheppach W. 1994. Effects of short chain fatty acids on gut morphology and function. Gut, 35:S35-S38.