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Excessive Copper in Dog Food May Cause Copper-Associated Hepatopathy (CAH)

Some commercial dog foods contain too much copper- its slow accumulation is quietly harming, and in too many cases, even killing some dogs.

We all know good nutrition is critical for the health and longevity of our dogs, and most of us rely on commercial dog foods to help us achieve that. Now, what if I told you those complete-and-balanced diets – the quality food you’ve carefully chosen for your dog – may be slowly killing him/her? High copper levels in dog food can cause a serious, potentially lethal, illness called dietary-induced, copper-associated hepatopathy (CAH, also known as copper storage disease). The incidence of CAH is increasing at a rate that’s causing alarm among veterinarians and dog owners, with one study showing 30% of canine liver biopsies revealing evidence of CAH.

The current “recommendation” of the Association of American Feed Control Officials (AAFCO) for the amount of copper in dog food is 7.3 mg/kg (milligrams of copper per kilogram of food).

The reason that “recommendation” is written in brackets is that’s not quite right – but only because the AAFCO that sets the standards for what constitutes a complete and balanced diet doesn’t publish recommended levels of any nutrients, just minimums and a few maximums. To make it simple and clear- the current legal minimum for copper in non-prescription dog food is 7.3 mg/kg – and owners of dogs who are at risk of developing CAH would be wise to feed only foods with copper levels as close to the minimum as possible. The European Pet Food Industry Federation (FEDIAF) uses a similar number (a small range, actually) for a minimum copper value in dog diets (7.2 to 8.3 mg/kg) – but it also imposes a maximum value for copper: 28.0 mg/kg. In contrast, the U.S. and Canada do not currently impose a maximum allowed value for copper, and it’s easy to find dry dog foods that contain copper levels that far exceed that amount. As result, CAH has been diagnosed with increasing frequency during the past decade in various pure and mixed-breed dogs that are not typically considered predisposed (like such breeds as Labrador Retrievers, Bedlington Terriers, Dalmatians, Doberman Pinschers, and West Highland White Terriers ). So this issue should be of concern to everyone who feeds their dog a commercial dry kibble diet.


To protect your dog, the first step is to learn how much copper is in your dog’s food; the second is to make sure you feed products with lower copper levels. Taking that first step, unfortunately, often means contacting the maker of your dog’s food and asking about its copper content. And to appreciate the answers to these questions, you first need to understand the terms that may be used in those answers.

Nutritional values may be reported in one of three ways. To compare products, you may have to convert the values reported to you into a different form (or ask the pet food company if they can give you the values in the specific form you need). The three ways that nutrient values may be expressed are:

  • As fed. The nutrient levels that are printed on dog food labels are expressed “as fed” – the values given are for the food in its packaged form. For example, Royal Canin’s dry prescription “Hepatic” diet lists its copper content as 7 mg/kg (max) as fed. This means there are a maximum of 7 milligrams of copper per kilogram of the food.

👉Note: Some food companies may use “parts per million (PPM)” instead of mg/kg. Mathematically, parts per million is equivalent to milligrams per kilogram; 4 ppm is the same thing as 4 mg/kg.👈

  • Dry matter (DM). These values represent the amount of a nutrient present in the food after all the moisture (water) has been removed. Dry dog foods typically contain about 10% moisture; if the moisture was dehydrated away, the weight of the food would be different enough to increase the milligrams per kilogram numbers by about 10%. To use the Royal Canin Hepatic dry food example again, the dry matter value would be reported as 7.8 mg/kg DM (max).

  • Caloric basis (kcals). Some companies report their nutrient values on a caloric basis. Copper would be reported as the number of milligrams of copper per 1,000 calories. Reported this way, the Royal Canin Hepatic dry food contains 1.9 mg/1,000 kcal (max).

👉Keep in mind that these are three ways of expressing the same amount of copper in a given food. If you ask a pet food maker for a product’s copper content, you need to be able to recognize their answer as an as-fed, DM, or kcal value so you can make apples-to-apple comparisons to other foods.


Sadly, you can’t count on many pet food manufacturers – not even those who make copper-restricted dog foods! – to be immediately transparent about the amount of copper in their foods. Even the companies that make copper-restricted diets often fail to publish their products’ copper levels on their websites! Fortunately, they do respond to inquiries.

Ask the makers of your dog’s food about the copper content in their products, especially if your the dog is at higher risk of CAH. If his/her food contains more copper than the FEDIAF maximum (28 mg/kg), I would recommend changing foods to one with less copper. And regardless of breed, switching to a food with a copper content that’s closer to the minimum allowed seems wise.

I’m not a fan of the ingredients generally used in prescription diets (which always contain more plant-sourced proteins, food fractions, and by-products than I would like to see). Hence, in my opinion, the best dietary option for a dog who has CAH – or is a predisposed breed – would be a home-prepared or raw diet.

The original source for this article can be found here

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