Dogs are omnivores. That means they can survive by eating a variety of foods. (Cats, on the other hand, are obligate carnivores, which means they must have meat in their diet.) A balanced diet for dogs contains all the essential nutrients their bodies need to function, in the correct quantities and proportions. With all the research that's gone into canine nutritional requirements over the past few decades, it's safe to say that our dogs probably eat more healthily than we do.
Who Sets Nutritional Requirements?
The nutritional requirements for dogs are set by two organizations: the National Research Council (NRC), and the Association of American Feed Control Officials (AAFCO). NRC recommendations are made by an international committee of animal nutrition experts and are updated as needed. The committee's report includes such information as how a dog's body metabolizes nutrients, the diseases related to poor nutrition, signs that a dog is suffering a nutrient deficiency, and the minimum daily nutrient requirements for dogs. The nutrient requirement recommendations are based on a dog's activity level and life stage (such as puppy, adult, or senior). Both of these factors have a large influence on a dog's nutrient needs.
The nutritional adequacy statement on a dog food label must say which life stage the product is made for: growth/lactation (puppies or pregnant/lactating females), maintenance (adults), or all life stages (any dog). AAFCO recognizes only two life-stage profiles, growth/lactation and maintenance. Therefore, a food labeled for “seniors” or “large breeds” simply meets their requirements for adult dogs.
When they're formulating foods, however, dog-food manufacturers rely on nutrient profiles from AAFCO, which are based on commonly used ingredients. These provide recommendations for practical minimum and maximum levels of nutrients in dog foods. The NRC recommendations come from studies in which higher-quality nutrients are used. Without input from the AAFCO, pet foods might be nutritionally deficient.
When you look on a bag or can of dog food, somewhere on the label should be a statement that the food is formulated to meet the nutritional levels established by AAFCO, or that feeding tests using AAFCO procedures substantiate that the food provides complete and balanced nutrition. Ideally, the manufacturer uses feeding trials to prove that a food is complete and balanced rather than simply mixing together a recipe without actually feeding it to dogs. The 2003 NRC recommendations contain new information about canine nutritional needs, so it's possible that AAFCO nutrient profiles will change in the near future.
The manufacture of pet foods is governed by the federal Food, Drug, and Cosmetic Act, which mandates that pet foods, like human foods, be pure and wholesome, contain no harmful or deleterious substances, and be truthfully labeled. Dog-food ingredients must be “generally recognized as safe” (GRAS for short), and dog foods must have labels listing all the ingredients. An ingredient list is useful for telling you what's in a food, but it can't tell you the quality of the ingredients. However, there are some tricks to reading a label that will help you be a more informed dog-food shopper.
Dietary protein contains ten essential amino acids that dogs cannot make on their own. The best dog foods have meat protein as the first ingredient. Protein from meat is higher in quality than protein from grains. Forms of meat protein include meat by-products and meat meals, which is meat that's been heat-processed to remove fat and water.
Ingredients are listed by weight, in descending order. That means the food should have more of the first ingredient than anything else. While some dog foods may list meat as the first ingredient, if you look farther down the label you may notice that it also lists a particular grain in several different forms, such as wheat flour, flakes, middlings, or bran. Individually, each form of wheat might make up only a small part of the food, but together they may outweigh the meat it contains. Look for a food that contains a balance of meat and grain proteins.