A study by Hiney et al. (2021) found that dogs fed raw meat diets enjoy better overall health compared to those eating high-quality commercial kibble. Raw-fed dogs showed lower inflammation, healthier teeth and skin, and better digestion. Despite higher Blood Urea Nitrogen levels — likely attributed to increased protein intake —the benefits of raw diets may outweigh those of processed foods, suggesting a raw diet could be a superior choice for canine health.
In 2021, Hiney et al. compared health markers between client-owned raw-meat-fed (RMF) dogs and dogs fed a high-quality extruded commercial diet (ECD). They aimed to identify whether healthy RMF dogs exhibited differences in biochemical and hematological (blood) parameters and to determine whether RMF dogs had preferred clinical health scores.
The authors compared the risks between an RMF diet with those of an ECD. With improper handling or food storage, RMF diets pose the risk of bacterial contamination, and improperly formulated homemade recipes may create nutrient excesses or deficiencies. In contrast, processing methods employed to create ECDs can affect protein and amino acid bioavailability and destroy essential vitamins. Additionally, high temperatures used to process commercial diets can form advanced glycation end products (AGEs), which contribute to the development of chronic and age-associated diseases including cancer, neurological degeneration, diabetes, and cardiovascular disease. They further posited that a more diverse microbiome associated with RMF diets resulted in enhanced absorption of nutrients. This “increased bioavailability of nutrients and reduction of low-grade inflammation could explain the anecdotal results of improved health and reduction in disease states reported by (RMF) owners” (Hiney et al., 2021).
For the study, dogs were split into two feeding groups, with half following an RMF diet, and the other half fed an extruded commercial diet. Dental and ear canal health, serum biochemistry, urinalysis, and hematology results were recorded over a year. Testing was conducted by a single Veterinarian who was blinded to feed group.
In the ECD group, diets included Purina ProPlan (12 dogs), Hill’s (9 dogs), Iams (2 dogs), Taste of the Wild, Royal Canin, Diamond, and Pedigree (1 dog each). All dogs in the RMF group were fed either Titan Blends, Texas Tripe, or Ross Wells Distributor premade raw pet foods. The RMF dogs also received fresh, locally sourced groceries.
Most notably, the study identified a difference between Alkaline Phosphatase (ALP) activity, with results showing this to be 50% higher in ECD dogs. ALP is an enzyme in the blood that assists in the breakdown of protein (Lowe, et al., 2023). High levels of ALP in the blood may be indicative of liver disease or bone disorders, nutrient deficiency or cancer (Cleveland Clinic, 2021). Upon further analysis, the researchers suggested that elevated ALP levels may be a response to nutrient modifications or AGE exposure in commercial diets. “In human nutrition, it is well accepted that processed food consumption is associated with both low-grade chronic inflammation and oxidative stress, both of which are known to induce hepatotoxicity and ALP activity” (Hiney et al., 2021).
It is also important to note, that this study detected elevated Blood Urea Nitrogen (BUN) concentrations in the raw-fed group. As BUN is a byproduct of protein breakdown and increased levels may indicate kidney damage, it is often used in the detection of renal failure. However, RMF dogs may be likely to exhibit higher than reference BUN levels due to high protein consumption. This aligns with the findings in other studies. Back in 2005, Dr. Jean Dodds led a study on RMF dogs that consistently demonstrated higher than average BUN, and suggested revision of the reference values to allow Veterinarians to more accurately assess RMF dogs. In follow-up, 34 out of the 37 dogs that indicated microalbuminuria (an early sign of kidney disease) in the study found that their elevated BUN was not related to a pathological condition. While elevated BUN is always worth exploration, it has been suggested that the elevated levels seen in RMF dogs are normal for pets fed high-protein diets.
Additional differences between RMF and commercially fed dogs included a decrease in inflammatory markers in the RMF group, noticeable improvement in dental, ear, and skin health, and better stool consistency, over dogs fed commercial diets (Hiney et al., 2021).
As such, it is our opinion that the observable health outcomes associated the RMF dogs are favourable over those found even in high-quality commercial diets. Blood test reference values should be handled with care during the assessment of RMF dogs, as research indicates different values are consistently observed depending on diet type.
References
Cleveland Clinic. (2021, November 4). Alkaline Phosphatase (ALP): What It Is, Causes & Treatment. Cleveland Clinic. https://my.clevelandclinic.org/health/diagnostics/22029-alkaline-phosphatase-alp
Dodds, J, Dr., Study of Microalbuminuria in Dogs Fed Raw Food Diets. (2019). Tumblr. https://drjeandoddspethealthresource.tumblr.com/post/35814186848/raw-diet-affect-on-dog-urine-kidney-renal
Hiney, K., Sypniewski, L., Rudra, P., Pezeshki, A., & McFarlane, D. (2021). Clinical health markers in dogs fed raw meat based or commercial extruded kibble diets. Journal of Animal Science, 99(6). https://doi.org/10.1093/jas/skab133
Lowe, D., Sanvictores, T., Zubair, M., & John, S. (2023). Alkaline Phosphatase. Nih.gov; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK459201/
