We all know that, by nature, dogs are primarily carnivores, but this does not mean that they necessarily benefit from a high protein diet. However there are some circumstances where high protein dog food, especially that made with high quality protein, is not only beneficial but even essential to dogs' health.
Protein requirements in dogs greatly vary depending on the individual dog's life stage, activity level, health and physiological condition, as well as on factors related to the overall diet of any single dog. A regular intake of dietary protein is essential to provide for tissue growth and maintenance and to sustain normal metabolic processes. That is why dogs who are in their growth stage (puppies and young dogs) and those who have increased metabolic demands (such as lactating females and athlete dogs) usually benefit from a diet based on high protein dog food.
Puppies and young dogs require high levels of dietary protein, since proteins provide the building blocks for tissues such as muscles, skin, hair and other connective tissues in many organs and are essential for the proper development of the brain. In addition, during the growth stages, dietary proteins have to be of high quality and highly digestible, in order to provide the body with enough amounts of all the essential amino acids needed for the growth and development of the new tissues. In females at the latest stages of pregnancy and during lactation, high protein dog food is essential, respectively, for the proper physical development of the foetuses and for the proper production of good quality milk, which contains relatively high amounts of protein. In addition, it should not be forgotten that a high level of dietary protein is also beneficial to sustain the health of the bitches themselves, since late gestation and lactation pose a high metabolic demand on the maternal body. Finally, in athlete dogs, and especially those who practice highly intense physical activities, protein requirements are increased due to the increased degradation and synthesis of muscle proteins and the increased use of proteins to produce energy during exercise.
The Importance of Protein in Dog Food
In all the circumstances described above, the protein content of the diet should not be lower than 25% (a percentage of protein between 25% and 30% can be considered as an optimal level). However, it is not only the percentage of dietary protein but also its quality that is crucial for the health of puppies, pregnant and lactating females and athlete dogs. The protein quality can be judged on the basis of its usability and its digestibility. The usability of a protein refers to its content and proportion of essential amino acids (the amino acids that the dog's body is not able to synthesize and have to be supplied in the diet): the more usable a protein is, the better its content and proportion of essential amino acids are. The digestibility of a protein refers to the ability of the digestive enzymes of the dog to break down it to simple amino acids that can be absorbed from the intestinal lumen and then used to build the proteins of the dog's body itself or to produce energy. Of course, the more usable and digestible the protein, the better its quality and the lesser the amount of food needed to provide the dog with the optimal level of amino acids it requires. So, when considering the protein content of a commercial dog food, it is important not only to look at the percentage of protein indicated on the label, but also at the protein source. Needless to say that the best protein for dogs is that coming from real meat, fish and eggs, while vegetable protein and protein derived from animal by-products (which mainly contain collagen) have a worse amino acid profile and are usually less digestible.
As it has already said, high protein dog food is not necessarily beneficial to dogs' health. In fact, there are certain circumstances where it may be even dangerous. In order to understand this fact, it is important to remember that the amino acids in excess of those needed for protein synthesis are not stored as such in the body, but they are deaminated (that is, they lose their nitrogen-containing amino group) and used to produce energy or stored as glycogen or body fat, while the nitrogen-containing amino group is converted into urea and then removed from the body by the kidneys. That is why a high protein diet may pose a severe strain on the kidneys and is not recommended for dogs with renal impairment or other renal disorders. In these cases, the kidneys may not be able to remove from the body the excess of nitrogen (in the form of urea) derived from the deamination of excess amino acids, with consequent intoxication from urea and from other nitrogen-containing waste products. High protein dog food should be avoided in senior dogs, as well, since their body is usually less able to digest dietary proteins and their kidneys work less efficiently than those of an adult dog in good health.
From what it has been said above, it should be clear that the choice of feeding one's dog a high protein dog food should be well thought out and extensively evaluated with a keen eye to the individual dog's health, life stage and physical activity and always remembering that it is not only the percentage of dietary protein that makes the difference, but it is also its quality and its source.