The gut microbiome plays an increasingly recognised role in dog health, immune function, and behaviour. Diet choices significantly shape microbiome composition and downstream wellbeing outcomes.
The canine gut microbiome is an active area of veterinary research with real welfare implications. A diverse, balanced microbiome appears to support immune function, reduce systemic inflammation, and may influence emotional regulation through the gut-brain axis. Dogs fed diets rich in fermentable fibre — such as vegetables, legumes, and whole grains — tend to have more diverse microbiomes with higher proportions of beneficial bacteria. Ultra-processed kibble with low fibre content is associated with less microbiome diversity. However, the evidence base for specific dietary interventions remains developing — well-formulated complete commercial diets still form the backbone of sound canine nutrition, and extreme dietary trends such as raw meat or grain-free diets carry documented risks. Probiotics and prebiotics show modest benefits in specific contexts, particularly after illness or antibiotic treatment.