Roles of plant‐based ingredients and phytonutrients in canine nutrition and health

Dogs possess the ability to obtain essential nutrients, established by the Association of American Feed Control Officials (AAFCO), from both animal- and plant-based ingredients. There has been a recent increase in the popularity of diets that limit or completely exclude certain plant-based ingredients. Examples of these diets include 'ancestral' or 'evolutionary' diets, raw meat-based diets and grain-free diets. As compared to animal sources, plant-derived ingredients (including vegetables, fruits, grains, legumes, nuts and seeds) provide many non-essential phytonutrients with some data suggesting they confer health benefits. This review aims to assess the strength of current evidence on the relationship between the consumption of plant-based foods and phytonutrients (such as plant-derived carotenoids, polyphenols and phytosterols) and biomarkers of health and diseases (such as body weight/condition, gastrointestinal health, immune health, cardiovascular health, visual function and cognitive function) from clinical trials and epidemiological studies. This review highlights the potential nutritional and health benefits of including plant-based ingredients as a part of balanced canine diets. We also highlight current research gaps in existing studies and provide future research directions to inform the impact of incorporating plant-based ingredients in commercial or home-prepared diets.