The gut-brain connection in dogs — and how food influences emotion, focus, and resilience

We’ve long understood that what we feed our dogs affects their bodies. But emerging research reveals something even more fascinating: diet also shapes how dogs feel, think, and behave.

From anxiety and reactivity to focus and emotional stability, your dog’s brain is deeply influenced by what happens in their gut.

This phenomenon occurs thanks to the gut-brain axis, a two-way communication system between the gastrointestinal tract and the nervous system, which is driven by microbes, hormones, and immune signals.

Gut feelings

Within your dog’s digestive tract resides a vast and dynamic ecosystem of bacteria, fungi, and other microbes, collectively referred to as the microbiome. These organisms:

• Digest fibre and produce short-chain fatty acids
• Train the immune system
• Produce neurotransmitters like serotonin, dopamine, and GABA
• Influence inflammation levels, stress response, and even fear-based behaviours

In fact, about 90% of serotonin — the ‘feel-good’ neurotransmitter — is produced in the gut.

When the gut microbiome is balanced, dogs are more likely to be calm, adaptable, and cognitively sharp. When it’s disrupted, they may be more anxious, reactive, or sluggish.

How diet shapes mood and mind

1. Processed diets and dysbiosis

Highly processed, carbohydrate-heavy diets (especially those with artificial colours, flavours, and preservatives) may contribute to dysbiosis — an imbalance in gut microbes that increases inflammation and alters brain chemistry.

Some dogs on poor-quality diets may exhibit:

• Irritability or over-arousal
• Poor impulse control
• Low energy or ‘brain fog’
• Chronic itching, gas, or soft stools

2. Protein and amino acids

Proteins break down into amino acids — the building blocks of neurotransmitters. Tryptophan, for example, is needed to make serotonin.

A low-protein or poorly balanced diet can leave dogs mentally flat or emotionally unstable. On the flip side, too much protein in sensitive dogs may increase arousal or frustration, particularly in working breeds.

3. Fats and omega-3s

The brain is nearly 60% fat,  and it thrives on the right kinds of fats. Omega-3 fatty acids, particularly DHA, are vital for brain health, memory, and emotional regulation.

Many commercial diets are low in omega-3 fatty acids, especially if not supplemented or protected from oxidation.

4. Fibre and fermentation

Prebiotic fibres (found in vegetables, fruits, and certain grains) feed beneficial bacteria. These bacteria, in turn, ferment fibre into short-chain fatty acids that reduce inflammation and support brain function.

Low-fibre diets or dogs on long-term antibiotics may lack this fermentation support, impacting everything from mood to immune resilience.

Real-world behaviour shifts

For the reasons given above, for some dogs, changing their diet can dramatically reduce:

• Separation anxiety
• Noise phobias
• Reactivity to strangers or other dogs
• Hyperactivity or attention problems
• Cognitive decline in senior dogs

In practice, these shifts are often subtle but significant: a dog that settles more easily after meals. A fearful rescue who begins to explore. A senior who regains curiosity and engagement.

Practical feeding tips for behavioural wellness

You don’t need to switch to raw or gourmet meals to support your dog’s brain, but intentional changes can go a long way.

• Choose diets with whole, recognisable ingredients. Minimise artificial additives and fillers.
• Feed prebiotics and probiotics. Look for foods with added inulin, fructooligosaccharides (FOS), or live cultures, or speak to your vet about reputable supplements.
• Incorporate fermented foods (if tolerated). Small amounts of plain kefir, sauerkraut brine, or fermented vegetables can offer microbial diversity.
• Add omega-3s. Look for fish oil supplements with DHA and EPA, or foods that include marine oils.
• Avoid constant switching. Sudden diet changes can disrupt the gut microbiome. Transition slowly, especially in sensitive or anxious dogs.
• Talk to your vet about any persistent gastrointestinal (GI) or behavioural symptoms. Sometimes, issues like fearfulness, hypervigilance, or GI distress may be gut-linked, but may also signal deeper medical conditions.

Feeding the whole dog

We often look to training to fix behavioural problems, and training is vital, but if the brain isn’t nourished, no amount of repetition will help your dog feel truly calm, confident, or safe.

Food is not a cure-all. However, when combined with thoughtful handling, a suitable environment, and empathy, it becomes one of the most powerful tools we have for behaviour change.