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Copper Levels in Dog Food: How Much is Too Much?

As responsible pet owners, we strive to provide our fur babies with the best nutrition possible. However, recent concerns have surfaced regarding the levels of copper in commercial dog food. Copper is an essential mineral for canine health, but like many good things, too much of it can lead to problems. In this blog post, I’ll explore the significance of copper in your dog’s diet, the potential risks of excess copper, and what you can do to ensure your canine companion does not receive too much.

The Importance of Copper in Canine Nutrition

Copper is a trace mineral that plays a crucial role in various physiological processes in dogs. It is essential for the formation of connective tissues, bone development, and the production of enzymes involved in iron metabolism. Copper also contributes to the overall health of a dog’s skin, coat, and immune system. While it is undeniably important, the key lies in maintaining the right amount.

How Do Dogs Acquire Copper? 

Dogs acquire copper via their diet. Copper is absorbed in the small intestine, transported to the liver and either used by the body, stored in the liver, or eliminated in bile. 

Copper is found in foods such as organ meats and sweet potatoes, however it is very difficult to formulate a pet food with the right amount of each essential vitamin and mineral using ingredients alone, especially when accounting for processing and storage losses. This is why responsible pet food manufacturers add vitamins and minerals to the food as “premixes” – and this applies to all forms of food from kibble to fresh food. Premixes help ensure that the correct levels of the micronutrients are evenly distributed in the finished product. Organic forms of minerals (aka chelated minerals) are also commercially available as premixes. Chelated minerals, often used in high quality dog foods, are those that are already bound to amino acids, which may make it easier for the body to absorb and metabolize for critical functions essential to health. Chelated and non-chelated forms can be used together to ensure adequate mineral levels.

Now back to copper. Historically, an inorganic form of copper, copper oxide, which has low bioavailability (ability to be used by the body) was used in pet food premixes. In 1997, following a publication, AAFCO modified their ​​recommendations for dietary sources of copper, recommending that feed-grade copper oxide be replaced with more bioavailable forms of copper. As a refresher, AAFCO, the Association of American Feed Control Officials, is an organization made up of federal and state regulatory officials that has established nutritional requirements, guidelines for standard ingredient definitions and product labels, and feeding trial protocols for pet foods. However, AAFCO does not directly test, regulate, approve or certify pet foods to make sure that they meet these standard requirements.

Risks of Excess Copper in Dog Food

Is there really such a thing as too much of a good thing? Yes. Excess copper provided by the diet is stored in the liver, where it accumulates. Over time, this causes inflammation and damage, and can result in copper toxicity, causing liver damage and compromising the overall health of the dog. 

Dogs with copper toxicosis may exhibit symptoms such as lethargy, jaundice, vomiting, diarrhea, and in severe cases, neurological issues. Identifying these symptoms early is crucial for prompt veterinary intervention. Certain breeds, such as Bedlington Terriers, Labrador Retrievers, and Doberman Pinschers, are genetically predisposed to copper accumulation. For these breeds, monitoring copper levels in their diet is especially important.

How Much Copper Do Dogs Need? 

AAFCO provides only a minimum recommended amount of copper, believing that pet food manufacturers would strive to meet this minimum requirement – 12.4 mg/kg DM for growth and reproduction and 7.3 mg/kg DM for adult maintenance. What has happened instead, is that many vitamins and minerals are overdosed via the “premix” and more likely to be provided in excessive amounts due to ingredients sought after by consumers. For example, there has been a push for more “ancestral diets” which contain mostly animal ingredients – which are inherently high in copper. 

What does this mean for our pets? Well trends in the pet food industry that are consumer-driven, as well as the use of more bioavailable forms of copper and premixes has led to an increase in copper concentration of commercial pet foods, often exceeding the biologic requirement of dogs and exceeding the tolerance limit for some of them.

In fact, studies have shown that the mean copper concentration in the livers of dogs has progressively increased from <10 μg/g in 1929 to 453 μg/g in 1995, and results of various studies suggest that high hepatic copper concentrations in dogs reflect high copper content in commercial dog foods. This is supported by clinical experience, where veterinarians believe they are seeing an increased incidence of copper-associated hepatopathy in dogs over the past 20 years, seemingly coinciding with the use of more bioavailable forms of copper.

It is not that more bioavailable forms of copper are a bad thing, it is that the recommended amounts did not change as well.  

AAFCO vs FEDIAF

Currently, as of 2023, the minimum recommendation for copper provided by AAFCO is 12.4 mg/kg DM for growth and reproduction and 7.3 mg/kg DM for adult maintenance. As mentioned, AAFCO does not provide a maximum recommendation.

FEDIAF is the European Pet Food Industry Federation, and unlike AAFCO, they do have a maximum amount of allowable copper – 28 mg/kg DM. FEDIAF requirements are generally known to be more stringent than AAFCO requirements. 

What Can Pet Owners Do?

As a pet owner, the best thing you can do is to contact the manufacturer of your pet’s food and ask for a nutritional analysis that shows the true amount of copper in their specific food. Make certain that the amount of copper does not exceed 28 mg/kg DM. 

At Wild Earth, we believe in transparency. That being said, the true amount of copper in our diets are as follows:

Wild Earth Maintenance Golden Rotisserie contains 26.8 mg/kg DM

Wild Earth Maintenance Classic Roast contains 20.7 mg/kg DM

Wild Earth Performance contains 19.8 mg/kg DM 

As you can see none of out diets contain potentially toxic levels of copper. We take both AAFCO and FEDIAF recommendations into account when formulating our foods in order to ensure we are giving dogs the best possible nutrition. 

The Conclusion on Copper

While copper is undoubtedly essential for your dog’s health, the key lies in providing them the right amount in their diet. Excessive copper levels in dog food can lead to serious health issues, especially in breeds predisposed to copper accumulation. As a pet owner, it’s crucial to be vigilant about your dog’s diet, and contact your pet food manufacturer for accurate copper levels. As always, if you are concerned your dog may be suffering from copper toxicosis, consult with your veterinarian. to ensure that your canine companion receives the optimal nutrition for a healthy and happy life. 

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Tiffany Ruiz Dasilva, VMD, cVMA

Dr. Tiffany Ruiz Dasilva is the Professional Services Veterinarian here at Wild Earth. She received her Bachelor of Science degree in Biology from Brown University, and attended veterinary school at the University of Pennsylvania School of Veterinary Medicine. Since graduation, she has worked in general practice, on telehealth platforms, and in animal rehabilitation. She has worked tirelessly to gain expertise in the field of canine nutrition through numerous certifications and coursework, and plans to pursue her Masters in Animal Nutrition.

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