PurebitesTuna Broth for Dogs, Only 4 Ingredients

A fish used mostly in cat foods, where its strong flavor is the point. Tuna is a good protein and a source of omega-3 fats. Two cautions apply to tuna fed often: it is higher in mercury than smaller fish, and cats can become fixated on it and refuse other foods. Both cautions apply to the cat eating tuna every day, and much less to tuna as one ingredient in a complete food fed in rotation.

A vegetable that contributes a little fiber and beta-carotene and a lot of label appeal. In dry food it is usually present in small amounts well down the list. It is not an allergen of concern and not a meaningful protein or calorie source. Fine to see; not a reason to choose one food over another.

A leafy green added in small amounts for vitamins, minerals and color. Spinach is high in oxalate, which binds calcium and in large quantities is a concern for pets prone to calcium oxalate bladder stones. The amounts in a complete food are tiny, often a fraction of a percent, so for most pets it is a token vegetable with no nutritional or safety weight.