Excessive Copper In Commercial Dog Foods?

Hello, Summarians!

I don’t think of myself as a conspiracy theorist, but ever once in a while, you run into a study that makes you wonder who to trust. Why don’t we have upper limits regarding copper levels? The evidence seems compelling. What are your thoughts?

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Bomb Dog Readiness

Forensic science in the United States is organized into several major subject areas under the Organization of Scientific Area Committees (OSAC), including the Scene Examination SAC, which houses the Dogs and Sensors subcommittee. Detection canines are treated as biological sensors due to their exceptional olfactory abilities—far surpassing most field-deployable analytical instruments—making them a cornerstone of explosive, drug, and human remains detection. Yet despite their widespread use, the scientific validation of canine performance and certification methods has lagged behind other forensic disciplines. 

Efforts toward standardization emerged in the 1990s with the creation of Scientific Working Groups (SWGs), including SWGDOG, which issued extensive guidelines for canine detection between 2004 and 2014. Broader concerns about variability and insufficient validation across forensic fields were highlighted by the 2009 National Research Council report, prompting NIST to establish OSAC in 2014. OSAC absorbed and updated the SWGDOG guidelines so they could be transformed into formal standards. This process culminated in the publication of ANSI/ASB Standard 092 in 2022, which defines minimum requirements, terminology, and protocols for training and certifying explosive detection dogs (EDDs). This standard intends to create consistent, empirically grounded certification criteria that better predict whether a team is ready for real-world operations. 

To evaluate whether Standard 092 actually reflects operational readiness, researchers conducted a proof-of-concept black box study—an approach increasingly used in forensic science to measure accuracy without probing underlying mechanisms. Across three U.S. locations, 56 canine/handler teams completed two types of tests: the formal Standard 092 certification assessment and a second set of more realistic, operationally challenging scenarios. Performance varied across trials, explosive types, and test days. Trial 2 produced the highest correct alert rates, whereas Trials 1 and 3 showed lower performance. Many teams improved from Day 1 to Day 2, suggesting effects of familiarity, reduced anxiety, or improved search strategy. However, Trial 3 teams showed little or no improvement. 

At the individual level, none of the 54 teams that completed at least one full day met the Standard 092 passing threshold of at least 90% correct alerts and fewer than 10% false alerts. The best-performing team achieved an 88% correct alert rate. Several factors likely contributed to the difficulty: the OSAC standard is more rigorous than many existing certifications; some explosives required by the standard are difficult to obtain for regular training; long testing days may have caused fatigue; and handlers may have faced stress or unfamiliar testing conditions. Physical and biological factors, such as high temperatures, exertion-induced decreases in olfactory sensitivity, and arousal levels, may also have affected performance. 

False alert patterns differed among trials and often concentrated on distractor items commonly encountered in training—such as Sharpie markers, dryer sheets, and anti-static bags—indicating possible cue-based or contamination-based learning histories. Parcel searches proved particularly challenging when boxes were sealed with tape, highlighting a mismatch between training conditions and real-world search environments. Teams generally performed far better on Day 2, demonstrating that familiarity and appropriate preparation can improve the detection of concealed explosives. 

Despite overall low passing rates, performance on Standard 092 strongly paralleled performance in real-world scenarios. Teams that performed well in one context tended to perform well in the other, indicating that the standard has predictive value for operational readiness. Only two teams were notable exceptions, performing poorly on the standard but well in realistic scenarios. 

The study also underscored logistical limitations: Standard 092 requires substantial space, staffing, and time, making it challenging for smaller agencies to implement. The lack of double-blinding may have allowed assessors or handlers to inadvertently influence outcomes. 

Overall, the study revealed major gaps in consistency and preparedness among EDD teams, supporting the need for more standardized, empirically tested training and certification practices. Regular access to a wider range of explosive training aids, more realistic parcel search preparation, and more rigorous quality control practices appear essential. Importantly, the findings suggest that Standard 092 is a meaningful measure of operational competence, though many teams are not currently meeting its expectations. Future research should expand geographic sampling and extend this evaluation framework to other detection domains, such as narcotics and human remains detection, to build a stronger empirical foundation for canine forensic applications. 

Karpinsky M, Browning H, Quigley-McBride A, Bunker P, Chapman W, Prada-Tiedemann PA, DeGreeff LE. Explosive detection canines in the field: a multi-site black box validation study. Front Vet Sci. 2025 Oct 16;12:1668317. doi: 10.3389/fvets.2025.1668317.

Bottom line - There are some gaps.

New Biomarkers For Splenic Cancer

Splenic masses in older large-breed dogs range from benign lesions curable by splenectomy to aggressive malignancies, most commonly hemangiosarcoma, which has a poor prognosis. Because preoperative diagnosis is difficult, circulating microRNAs (miRNAs) are being investigated as minimally invasive biomarkers. MiRNAs regulate tumor-related genes and show altered expression both within tumors and in blood, making them promising diagnostic targets. Prior studies have demonstrated miRNA dysregulation in canine hemangiosarcoma tissues and plasma, supporting their potential utility. 

This study evaluated serum miRNA expression in dogs with splenic hemangiosarcoma before splenectomy, 24–48 hours postoperatively, and 10–30 days postoperatively. The hypothesis that tumor removal would alter circulating miRNA levels was supported. Four miRNAs—miR-126-5p, miR-150-5p, miR-214-3p, and miR-452-5p—showed postoperative decreases at one or more time points compared with preoperative levels, consistent with reduced release of tumor-derived miRNAs into circulation following splenectomy. 

MiR-126-5p decreased at both postoperative time points and remained suppressed through 10–30 days, aligning with its known role in angiogenesis and endothelial biology via VEGF signaling, relevant to the vascular origin of hemangiosarcoma. MiR-150-5p decreased shortly after surgery but returned to near-baseline levels by 10–30 days, potentially reflecting surgical healing, angiogenic regulation, residual disease, or limited statistical power. MiR-214-3p similarly decreased early postoperatively but did not differ at later sampling; this miRNA has anti-angiogenic effects and targets PTEN-related pathways involved in hemangiosarcoma pathogenesis. MiR-452-5p showed delayed reduction, decreasing only at the 10–30-day point; it has been linked in human cancer to suppression of the cell-cycle inhibitor p27, whose loss is implicated in angiosarcoma development. 

Other tested miRNAs—miR-203a-3p, miR-494-3p, miR-497-5p, and miR-543—did not demonstrate significant perioperative changes, despite known associations with angiogenesis and PTEN regulation in other tumors and in prior canine studies differentiating dogs with splenic disease from healthy controls. Nonsignificant trends suggested possible postoperative decreases or tumor-suppressive rebounds, but these findings may reflect type II error from small sample sizes. 

Limitations included potential undetected metastatic disease, reliance on radiographs rather than more sensitive imaging methods, lack of routine echocardiography, the likelihood of micrometastases, possible confounding comorbidities, and limited sample numbers, particularly at late follow-up. Larger studies are needed, especially to assess miRNA behavior in dogs with metastatic progression. 

Overall, reductions in miR-126-5p, miR-150-5p, miR-214-3p, and miR-452-5p after splenectomy support their relevance to tumor presence and biology, reinforcing their promise as components of a circulating, minimally invasive diagnostic panel for canine splenic hemangiosarcoma. 

Grimes, J. A., & Schmiedt, J. M. (2025). Circulating levels of microRNAs 126-5p, 150-5p, 214-3p, and 452-5p decrease following splenectomy in dogs with hemangiosarcoma. American Journal of Veterinary Research https://doi.org/10.2460/ajvr.25.07.0250 

Bottom line — Early results support this as a potential diagnostic path.

Copper Levels In Commercial Dog Foods

Copper is an essential micronutrient required for many metabolic processes, but its levels must be tightly regulated because excess copper accumulates in hepatocytes and induces oxidative injury and apoptosis (cuproptosis). In dogs, long-term copper intake exceeding an individual’s tolerance can disrupt hepatic homeostasis and lead to copper-associated hepatopathy (CuAH). 

Historical and comparative data indicate that liver copper concentrations in free-foraging wolflike canids (wolves, coyotes, golden jackals) are consistently low and overlap with values in healthy humans and dogs prior to the widespread commercialization of fortified dog foods. In contrast, modern pet dogs show markedly higher hepatic copper concentrations. The increase parallels changes in commercial dog food formulations after 1997, when poorly bioavailable copper oxide supplements were replaced with more bioavailable copper sources. Without adequate longitudinal safety studies, total dietary copper intake in dogs rose far above minimum requirements. 

Coyotes, eating diverse natural diets without copper premix supplementation, have significantly lower liver copper concentrations than pet dogs consuming AAFCO-compliant foods, and their values align with other wild canids. This supports dietary copper intake—not water contamination or plumbing—as the primary driver of hepatic copper accumulation in dogs. Genetic factors contribute in only a few breeds, such as Bedlington Terriers, and cannot explain the widespread increase in CuAH across most breeds since the late 1990s. 

Case-based dietary studies show that dogs fed low-copper diets (0.15–0.24 mg Cu/100 kcal, without copper premixes) are protected from copper accumulation, whereas diets ≥0.31 mg Cu/100 kcal are associated with higher hepatic copper and frequent rhodanine-positive staining, a marker of pathologic copper deposition. Even dogs fed “low-risk” diets often still have liver copper levels exceeding those of coyotes, highlighting the persistent impact of restricted dietary diversity and sustained intake from formulated diets. 

Current commercial dog foods typically contain 20–30 mg Cu/kg dry matter (≈0.5–0.8 mg/100 kcal), exceeding NRC and AAFCO minimum requirements by three- to fivefold. Neither NRC nor AAFCO sets an upper copper limit in US dog foods. European limits (28 mg/kg DM) and proposed “copper-restricted” diets (15 mg/kg DM) remain higher than levels shown to prevent hepatic copper accumulation in dogs. When tolerated copper intakes recommended for humans are scaled to canine body weight and energy needs, standard commercial foods commonly exceed predicted safe daily intakes for dogs, particularly in older animals with prolonged exposure. 

Histologic evidence further supports risk: rhodanine-positive hepatocellular copper deposition—considered abnormal in adult mammals—was present in approximately 38% of dogs consuming ≥0.31 mg Cu/100 kcal diets, but absent in dogs fed low-risk diets and in coyotes. Importantly, stainable copper may precede biochemical or histologic injury and can potentiate oxidative damage or act as a “second hit” amplifying liver injury from unrelated insults. 

Longitudinal canine data on copper adequacy and toxicity remain sparse, especially in mature nonreproductive dogs. Available puppy studies suggest that copper intakes within or slightly above the low-risk range are sufficient to prevent deficiency while avoiding excessive hepatic accumulation, whereas higher intakes substantially elevate liver copper stores. Declines in hepatic copper after dietary restriction occur slowly over months to years. 

Overall, evidence indicates that contemporary commercial dog foods contain copper levels exceeding the tolerable upper limit for many dogs, likely contributing to the rising prevalence of copper-associated hepatopathy. The use of highly bioavailable copper premix supplements without a regulated maximum allowance and with minimal labeling transparency appears to be the central problem. Regulatory reevaluation of dietary copper limits and mandatory disclosure of total copper content in dog foods are needed to reduce unnecessary copper exposure and protect canine hepatic health. 

Center, S. A., VanVranken, P., Randolph, J. F., Friesen, C. H., Dowdy, B. G., Hull, M. C., Miller, A. D., Wakshlag, J. J., Glahn, R., & Wiesinger, J. A. (2025). Significantly higher hepatic copper concentrations in dogs compared to coyotes implicate excessive copper in most commercial dog foods. Journal of the American Veterinary Medical Association https://doi.org/10.2460/javma.25.05.0297 

Bottom line — Very concerning.

Just putting things in perspective …