Dog Nutrition
The domesticated dog is classified as Canis lupus familiaris of the Canidae family and in the order of Carnivora. Evidence in their biology and behavior suggests that the grey wolf is the ancestor of domestic dogs. To best understand dog nutrition it is good to understand a dog’s biology.
Like their ancestor, the grey wolf, dogs are carnivores and there is ample evidence of this in their biology. Starting from their mouth, you can see that they have sharp pointed teeth that are optimized for tearing meat. Their mouths also lack flat molars that are used by herbivores and omnivores to grind vegetable matter. The manner in which a dog chews is also consistent with that of a carnivore, a dog’s jaw is hinged for it to chew in an up and down unlike the jaws of herbivores that chew side to side in order to mash and grind vegetable matter.
Carnivores have relatively shorter digestive tracts than herbivores and omnivores. Vegetable matter is digested in a longer and slower process and requires the longer digestive system and thus the longer digestive tract in herbivores and omnivores. A dog’s digestive tract is short and is consistent with that of a carnivore.
Dogs, however, are not obligate carnivores like cats. Cats can only digest meat efficiently and obtain all of their nutrition from meat. Dogs are able to digest carbohydrates and obtain energy from the digestion of carbs. That being said, a dog’s best nutrient is protein.
Dogs need protein
Protein is an essential element in a dog’s diet. Proteins contribute to energy, muscle repair, a healthy immune system, and healthy coat and skin. Protein can come from a variety of sources such as meat, eggs, and even grains and vegetables. However not all proteins offer the same nutritional value.
Proteins are built with amino acids. When proteins are digested, they are broken down to amino acids which are used to maintain a dog’s biological functions. Amino acids are classified as essential and non-essential. Non-essential amino acids can be synthesized by the dog whereas essential amino acids can only be obtained from dietary sources. There are ten essential amino acids in a dog’s diet and these are:
- Arginine
- Histidine
- Isoleucine
- Leucine
- Lysine
- Methionine
- Phenylalanine
- Taurine
- Threonine
- Typtophane
- Valine
Not all proteins contain all the essential amino acids. Proteins are classified as high quality and low quality depending on the number of essential amino acids a protein contains. Egg whites are amongst the highest quality of proteins available followed by animal proteins, plant proteins are amongst the lowest grade proteins available.
It is not necessary to try to calculate which proteins contain which amino acids. A diet featuring proteins from a variety of sources will balance out nutritional deficiencies.
Commercial dog food will often boost their protein percentage by adding in plant source proteins but remember that these are very low quality proteins and just because a commercial dog food label shows a high protein content, doesn’t mean it’s good nutritionally for your dog.
Carbohydrates
Dogs are able to eat and digest carbohydrates such as grains, corn, and vegetables and they are able to convert carbohydrates into energy. Carbs are ultimately broken down to glucose which is used as energy, but dogs are able to convert dietary proteins and fats to glucose as well.
Carbs do not seem to be harmful to dogs however many dogs have food allergies or intolerances to grains or corn. A large percentage of commercial dog food is carbohydrates because carbohydrates are a cheaper source of calories than proteins.
There is controversy on whether dogs require any carbohydrates in their diet. The National Research Council, the agency that sets the nutritional standards for dog food, does not list carbohydrates as a nutritional requirement. There is evidence that since a dog’s digestive system is not optimized for carbohydrate digestion, a diet too high in carbohydrates can result in constantly irritated bowels which may result in loose smelly stools or constant diarrhea.
Fats
Fats are a very important component in a dog’s diet. Fats are good for healthy coats and skin as well as a great source of energy for dogs. Dogs, being carnivores, are able to efficiently convert fat to energy. A dog’s biology reacts differently to fat than a human and do not carry the same risk of high cholesterol or heart disease from eating fat. Dogs also enjoy the taste of a fatty diet. I have still not met a dog that doesn’t love the taste of cheese.
Good sources of fat for dogs are animal fats, fish oils, and diary fats such as cheese and yogurt.