Nutrients are divided into subcategories: protein, carbohydrates, fats, vitamins and minerals, and water.
Protein in Dog Food
Common dog-food protein sources include meat, poultry, fish, and some plant ingredients such as corn gluten and soybean meal.
Protein is best known for supplying amino acids, or protein subunits, to build hair, skin, nails, muscles, tendons, ligaments, and cartilage. It also plays a main role in hormone production.
Dogs, best fed as carnivores, require essential amino acids, that are not all found in the correct balance in single plant-protein sources such as soybean meal.
Carbohydrates in Dog Food
Common carbohydrate sources are plants and grains. Carbohydrates, also categorized as starches (sugars) and fibers, provide energy and bulk, respectively.
Starches are made up of various types of sugar, such as glucose or fructose. Through digestion, dogs can easily convert sugar into usable energy.
Fiber may or may not be fermented or broken down into short-chain fatty acids by bacteria in a dog's intestines. Highly fermentable fiber sources, such as vegetable gums, provide high amounts of short-chain fatty acids. Moderately fermentable fibers, such as beet pulp, provide short-chain fatty acids and bulk for moving waste. Slightly fermentable fibers, such as cellulose, provide mainly bulk for moving waste through the digestive tract and only a few short-chain fatty acids.
Fats in Dog Food
Fats are found in meats, poultry, fish, and plant oils, such as flax and vegetable oils. Fat, for all of its bad press, fulfills many vital body functions. Animal-cell membranes are made of fat. Fat also helps maintain body temperature, control inflammation, and more. Fat is the primary form of stored energy in the body, providing twice as much energy as carbohydrates or proteins.
Fats also provide the important fat subunits, omega-6 and omega-3 fatty acids. Omega-6 fatty acids are essential for skin and coat maintenance and proper membrane structure. Omega-3 fatty acids have been shown to be important in blood clotting and decreasing inflammation.
Vitamins and Minerals in Dog Food
Vitamins are responsible for promoting bone growth, blood clotting, energy production, and oxidant protection.
Vitamins A, D, E, and K require fat for absorption into the body, while vitamins such as the B-complex vitamins and vitamin C need water to be absorbed into the body.
Minerals provide skeletal support and aid in nerve transmission and muscle contractions.
