Dog foods that are produced with human-grade ingredients have increased in number and popularity in recent years. In addition to containing food ingredients that are classified and handled differently than typical pet food ingredients, these products are usually less highly processed when compared with extruded kibble (see “Human Grade Dog Foods: Some Science” for details).
To date, there are only a few studies that have examined differences between traditional (pet-grade) foods and foods produced with human-grade ingredients. I have written about two of these in earlier essays. Here are short summaries:
- Digestibility Assay Study: A validated biological assay was used to measure macronutrient digestibilities of a set of fresh-cooked, human grade foods (Just Food For Dogs). Although dry matter digestibility values were not spectacular (possibly due to fiber content), the protein digestibility and amino acid availability values, indicators of protein quality, were very high in the human-grade foods (1).
- Feeding Study with Dogs: In this study, two varieties of Just Food For Dogs were compared with either an extruded, dry dog food or with a fresh-cooked food produced with pet-grade ingredients (2). The two human-grade foods performed better than the extruded dry food and than the pet-grade fresh-cooked food. Digestibility values of the human-grade products were rock stars (> 90 percent), less total food was needed to maintain dogs’ body condition, and the human-grade foods produced lower volume of feces.
Another Company Publishes
The two earlier studies examined the nutritional value of a single company’s human-grade, fresh-cooked foods (Just Food For Dogs). Recently, another producer of fresh-cooked foods added their data to the growing science on this topic (3). The study compared the performance of four varieties of foods produced with human-grade ingredients (NomNomNow) to a chicken-based extruded kibble. The brand of the dry kibble was not identified. Dogs were fed each food for a period of 10 days. Collected data included measures of digestibility, energy, and fecal quality.
- Digestibility Values: When fed to dogs, the extruded kibble had significantly lower dry matter, protein, fat and NFE (an estimate of carbohydrates) digestibility values compared with all four of the fresh-cooked products. The differences were dramatic. For example, dry matter digestibility of the kibble was ~ 82 percent. Dry matter digestibility values of all four fresh-cooked foods were 90 percent or higher.
- Protein: Similarly, protein digestibility of the kibble was ~ 85 percent. Protein digestibility values for the four fresh foods were between 92 and 94 percent (rock star values, once again).
- Feces: Dogs fed the fresh-cooked foods had significantly lower defecation frequencies (numbers of poops per day) and lower fecal volumes than when they were fed the kibble.
Take Away for Dog Folks
As with the earlier studies, these results suggest that foods made with human-grade ingredients that are produced with minimal processing perform well when fed to dogs. This is information that dog owners can use when evaluating and selecting healthful foods for their dogs.
Although (in my opinion) we still need controlled studies that tease out and quantify the respective influences of food processing versus initial ingredient quality, we do have a growing body of evidence telling us that both processing and ingredient quality matter in pet foods – a lot. (Remember, science loves replication). Moreover, these papers, published in academic, refereed journals, and either conducted or supported by actual pet food companies, provide great examples of industry transparency that is sadly often in short supply.
Which brings me to my soap box…….
Who produces research that we can use?
It is time to open this particular can o’ worms. I have now written about three independent studies of commercially produced, fresh-cooked human-grade dog foods. All three papers identified the companies and the brands that were tested. The data they reported included total digestibility values, protein/amino acid digestibility information, defecation frequency and fecal scores (important to many dog folks), among others. The first study showed mixed results, while the latter two demonstrated some clear wins. Moreover, although there were limitations, one study helped to tease apart the influence of ingredient quality versus that of processing. All good, practical and applicable information needed by dog folks and nutritionists alike.
So, here’s my beef (pun intended).
A common and highly (overly) shared assertion today regarding pet food selection centers on nutrition research and who exactly is doing that research. A frequent form that this “advice” takes is something along these lines (paraphrasing):
“It is the large companies that employ nutritionists and that are conducting all of the research on pet food and nutrition. Therefore, consumers should trust those companies to produce safe and nutritious foods”.
There is a problem with this belief.
It is not true: The type of information that we need to know about the foods that we select for our dogs is not being provided by the large multi-national companies. Really. It is not. Please stop saying that it is.
In contrast, in recent years academic researchers, and to a lesser degree small companies, have been providing us with literally boatloads of practical information that we can use about dog nutrition, pet foods and pet food ingredients. I know this. I have been writing about it. The published research, not coming from large companies, includes, among other topics, evidence regarding protein quality, the digestibility of dried protein meals, damage due to processing, fish oils, the type of starches that are used in pet food, new processing methods such as freeze-drying and freezing, the effects of HPP on raw foods, the potential health risks of excessive copper, mercury, and contaminating thyroid hormone in pet foods, and most recently, data regarding the use of new ingredients such as insect proteins and human-grade ingredients. With the exception of a single paper (published by nutritionists with Hills), that questioned current protein levels in pet foods, I have found no recent studies by the large companies that address the nutritional value, digestibility, ingredient quality or safety of their foods or of the ingredients that they include in their foods.
For all of the marketing gimmicks, label claims, and emotional appeals that we hear from the multi-national corporations regarding the superiority of their products, where are the studies that report digestibility values, protein quality indices, and poop scores? Where are the data to support claims of nutritious and healthy foods? If we are expected to believe all of the marketing claims, then it is time for the companies (and their nutritionist spokespersons) to step up and show us the data.
Until then, I will continue to write about studies that provide helpful information to dog folks about nutrition and to thank the researchers in academia (and from small companies) that are conducting and publishing this work.
Climbing Down Now.
- Oba PM, Utterback PL, Parsons CM, Swanson KS: True nutrient and amino acid digestibility of dog foods made with human-grade ingredients using the precision-fed cecectomized rooster assay. Journal of Animal Science 2020; 4:442-451.
- Do S, Phungviwatniku T, de Godoy MRC, Swanson KS. Nutrient digestibility and fecal characteristics, microbiota, and metabolites in dogs fed human-grade foods. Journal of Animal Sciences 2021; 99, https://doi.org/10.1093/jas/skab028
- Tanprasertsuk J, Perry LM, Tate DE, Honaker RW, Shmalberg J. Apparent total tract nutrient digestibility and metabolizable energy estimation in commercial fresh and extruded dry kibble dog foods. Journal of Animal Sciences 2021; In Press.