Protein – What do we mean by ‘high-quality’?

What is Protein?

Proteins are the building blocks of the body and an absolute necessity for the daily function of your dog. They are workhorses and do most of the work in cells; proteins are the main constituent of muscles, transport messages, and are required for the structure, function, and regulation of the body's tissues and organs.

Proteins are built up out of small units called amino acids. The body breaks down consumed proteins into individual amino acids or short chains, and rebuilds them once they have been absorbed. That way, like Lego, proteins can be broken down and reassembled for new purposes. Some amino acids can be made by the body if there is a shortage in the diet and some, which we call essential amino acids, have to be consumed. In dogs, there are ten essential amino acids, which are key for keeping your dog in tip-top condition.

How can Protein be High or Low Quality?

For your dog’s manipulation of protein and amino acids to be as efficient as possible, as well as giving those essential amino acids, the quality of the protein in the diet must be high. High quality protein means protein that is more easily absorbed by the body and more readily used. This is very important, especially when you consider dogs are unable to store protein for later. Low quality or un-necessary protein is excreted through the kidneys, and this can put pressure on this organ system.

The lack of storage capacity for protein, and requirement for the essential amino acids, means that dogs need to consume protein frequently. Depending on diet and lifestyle, using supplementary protein can improve the amino acid profile of the diet and support a healthy and active lifestyle.

[caption id="attachment_11518" align="aligncenter" width="300"] Dogs need essential amino acids as part of their daily diet.[/caption]

Which Dogs Need High Quality Protein?

The requirement for appropriate protein differs depending on the dog in question.

Puppies and working dogs require more protein than adult dogs leading a sedate lifestyle, so in these dogs giving extra can support healthy development of muscles and the systems used for exercise. Racing sled dogs for example require a diet containing over 30% protein, otherwise they develop an anaemia known as ‘sports anaemia’. In humans, whey protein supplements have been shown to improve muscle strength, increase exercise performance and lessen recovery time.

Studies have consistently demonstrated the acute benefits of protein supplementation on post-exercise muscle” – Pasiakos 2014

Ill or elderly dogs also have a requirement for high quality protein. Proteins with a high biological value are more tissue-sparing, meaning giving high quality protein sources such as whey can be safer than other proteins in animals with kidney disease, or old age muscle wastage. High quality protein, easily absorbed with the right amino acids at optimised levels, has also been shown to lower blood sugar and optimise lean body mass in middle aged and older humans.

Stressed dogs may also need better or more protein. One study concluded that the protein requirements for stress and hard work in dogs is more than 38 percent of the diet, and that at least 28 percent should be provided in the form of protein which has a quality (efficiency of utilization) of about 70 percent. Whey has the highest biological value of all the available protein sources.

Finally, dogs gestating or lactating also have increased nutritional requirements, and need about 25% protein in their diet - unsurprising when you consider the work that goes into reproduction!

What is Whey?

Protein can come from a variety of sources, both meat and plant. The dog is an omnivore, and can digest grains, meaning it can take advantage of all protein containing foods. An excellent source of protein is milk.  Milk contains two types of protein, whey and casein, and it is possible to separate out the whey element as this is the most high-quality protein of the two.

Whey isolates are typically at least 90% protein, contain all a dog’s essential amino acids, and are highly bioavailable. Whey also contains branched chain amino acids which are very highly concentrated in muscle tissues.

As well as a supportive effect on muscle development, whey proteins also support the levels of antioxidants within the body. Whey protein concentrate has been proven to increase levels of glutathione in the body, the primary antioxidant produced by the liver. This protects against damage by free radicals – reactive oxygen species which can damage cells and even DNA. This is especially useful in older animals, when levels of endogenous antioxidants often fall dramatically.


Whey is a fantastic source of protein for dogs, containing everything they need in a highly digestible form.  Different dogs, depending on size, age, health status and lifestyle, require different levels of protein. Having the ability to supplement extra protein in times of high demand gives owner flexibility over their dog’s diet, and allows more tailored nutrition.

“It is hard to (sic) generalize about dogs, simply because of the great diversity of form and behaviour within this species, resulting from its long history of domestication and the many different functions for which dogs have been bred.” – Bradshaw 2006

Nutrition is becoming a hotter topic, both for humans and dogs, and in the veterinary world awareness of the role of correct protein intake is growing rapidly. We know we as humans do not need the same nutrition every day, and neither do our dogs. Supplements are a fantastic and simple way to take back control, and feed your dog exactly what he needs.



Nutr. July 2006  vol. 136 no. 7 1927S-1931S. The Evolutionary Basis for the Feeding Behavior of Domestic Dogs (Canis familiaris) and Cats (Felis catus) John W. S. Bradshaw

J Nutr. 1991 Nov;121(11 Suppl):S128-39. Influence of dietary protein on renal function in dogs. Bovée KC1.

What role does dietary protein restriction play in the management of chronic renal failure in dogs? Devaux C1, Polzin DJOsborne CA.

J Nutr. 1991 Nov;121(11 Suppl):S140-4. Effect of modified protein diets in dogs and cats with chronic renal failure: current status. Polzin DJ1, Osborne CAAdams LG.

A Study of the Nutritional Effect of Grains in the Diet of a Dog Kristyn M. Souliere. University of Maine - Maine

Mobley A.R., Slavin J.L., and Hornick B.A. (2013) The future of recommendations on grain foods in dietary guidance. J. Nut. 182:9-13.

McNamara J.P. (2014) Principles of Companion Animal Nutrition: Volume 2 (Anthony V.C., ed), pp. 20-23. Pearson, Boston, MA.

Polzin D.J. (2013) Evidence-based stepwise approach to managing chronic kidney disease in dogs and cats. J. Emerg. Crit. Care. 220:205-215

Kronfeld D. S. (1977) Hematological and metabolic responses to training in racing sled dogs fed diets containing medium, low, or zero carbohydrate. Am. J. Clin. Nutr.30:419–430

Clin Invest Med. 1991 Aug;14(4):296-309.The biological activity of undenatured dietary whey proteins: role of glutathione. Bounous G1, Gold P

Nutr. January 2006  vol. 136 no. 1 Signalling Pathways and Molecular Mechanisms through which Branched-Chain Amino Acids Mediate Translational Control of Protein Synthesis Scot R. Kimball*, Leonard S. Jefferson*

Toxicol In Vitro. 2003 Feb;17(1):27-33. Effect of whey protein isolate on intracellular glutathione and oxidant-induced cell death in human prostate epithelial cells. Kent KD1, Harper WJBomser JA.

J Nutr Sci. 2014; 3: e34. Energy requirements for racing endurance sled dogs John P. LoftusMolly YazwinskiJustin G. Milizio, and Joseph J. Wakshlag

Sports Med. 2014 May;44(5):655-70. Effects of protein supplements on muscle damage, soreness and recovery of muscle function and physical performance: a systematic review. Pasiakos SM1, Lieberman HRMcLellan TM.