An assortment of protein sources provides a good balance of amino acids, eg by feeding pulses and cereals together at one meal. Dogs utilise unsaturated oils well.
Vitamin E helps in unsaturated oil metabolism.
Unsaturated oils are oxidised, reducing their nutritional value, by exposure to light, heat and air. Carbohydrates are unlikely to be in short supply in the average varied diet. The starch in potatoes can cause diarrhoea in some dogs. As vitamin D - Margarine, butter, eggs , milk . As its precursor, which is converted by sunlight on the animal's skin to vitamin D - green leafy vegetables, cereal germ, yeast.