Many premium dog foods list fruits and vegetables, and many labels promise what those ingredients will do. This is our attempt to sort what is known from what is marketed — including about our own recipes.
What phytochemicals and antioxidants are
Phytochemicals are compounds plants make that are not vitamins or minerals: anthocyanins in blueberries and tart cherries, carotenoids in carrots and pumpkin, flavonoids in apples, beta-glucans in shiitake mushrooms. Many act as antioxidants in the laboratory, meaning they neutralise reactive molecules that can damage cells.
Dogs also need certain antioxidant nutrients outright. Vitamin E and selenium are required nutrients in the AAFCO nutrient profiles; a complete and balanced food has to supply them whatever else it contains.
What the evidence supports in dogs
Antioxidant-fortified diets and ageing brains
In a two-year study published in Neurobiology of Aging in 2005, aged beagles fed an antioxidant-fortified diet and given behavioural enrichment learned more accurately than aged dogs given neither. Enrichment did much of the work, and the diet was a specially fortified research formula — but it is some of the better evidence that antioxidants matter to the ageing dog.
Vegetables in the bowl
A 2005 case-control study of Scottish Terriers found that dogs fed vegetables at least three times a week had lower odds of bladder cancer. It is an observational finding in one high-risk breed, not proof, but it is one of the few dog studies to look at whole vegetables rather than isolated extracts.
Where the claims run ahead of the evidence
- Most phytochemical research is in cells or rodents, often at doses no food could deliver. A compound that slows tumour cells in a dish has not been shown to do anything in a dog eating a normal diet.
- Amounts matter. In a complete food, fruits and vegetables are a minority of the recipe. They add variety and whole-food nutrients; they are not a supplement dose.
- No food “detoxes” a dog. The liver and kidneys do that job, and no ingredient has been shown to improve on them in a healthy dog.
How to read a label with this in mind
- Treat an ingredient list as a description of what is in the food, not of what it will do.
- Be sceptical of words like “anti-cancer”, “detox” or “immune-boosting” on any bag — ours included.
- Check for an AAFCO nutritional adequacy statement: that is what guarantees the required antioxidant nutrients are there.
Where Loyal Saints fits
Our recipes include blueberry, cranberry, tart cherry, strawberry, apple, carrot, pumpkin, spinach, broccoli, beet and shiitake mushroom alongside meat and organs. We include them as whole-food sources of antioxidants, fibre and variety — and we describe them that way, not as treatments. The full ingredient lists and our evidence standards are in the Science Center.
Sources
- Milgram NW, et al. Learning ability in aged beagle dogs is preserved by behavioral enrichment and dietary fortification: a two-year longitudinal study. Neurobiology of Aging 2005;26(1):77–90.
- Raghavan M, et al. J Am Vet Med Assoc 2005;227(1):94–100.
Common questions
Are antioxidants good for dogs?
Some are essential — vitamin E and selenium are required nutrients. Research in ageing beagles suggests an antioxidant-fortified diet, together with mental enrichment, supports learning. Claims beyond that are mostly based on laboratory studies.
Do blueberries prevent cancer in dogs?
There is no evidence that blueberries prevent cancer in dogs. They are a whole-food source of anthocyanin antioxidants and a reasonable part of a varied diet.
Do fruits and vegetables in dog food do anything?
They add whole-food nutrients, fibre and variety. In a complete food they are a small share of the recipe, so they should not be expected to act like a supplement or a medicine.
