Duplicate Minerals in Pet Food

Have you noticed that some pet foods list duplicate minerals? One mineral will be proteinated (such as Copper proteinate), and the pet food will also include another source of the same mineral (such as Copper sulfate). Why do some pet foods duplicate minerals?

Most pet foods use vitamin and mineral supplements to balance the diet; providing the pet with all of the required nutrients. With minerals, some pet foods use basic (feed grade) supplements such as the ingredient copper sulfate. Others use a higher quality (feed grade) supplement such as copper proteinate. And a few use human grade supplements or use the actual food ingredients to provide all required nutrients.

But, many pet foods are using duplicate minerals. Listing basic supplements in the ingredient panel – such as copper sulfate – and listing a chelated or proteinated mineral too – such as copper proteinate.

As example in this Canidae dog food…

Canidae Grain Free Pure Elements Lamb Dog Food Dry

Minerals: iron proteinate, zinc proteinate, copper proteinate, ferrous sulfate, zinc sulfate, copper sulfate, potassium iodide, manganese proteinate, manganous oxide, manganese sulfate, sodium selenite

And in this Wellness cat food…

Wellness Core Grain Free Original Formal Cat Food Dry

Minerals: Zinc Proteinate, Zinc Sulfate, Calcium Carbonate, Iron Proteinate, Copper Sulfate, Copper Proteinate, Manganese Proteinate, Manganese Sulfate, Sodium Selenite

Notice that both of these pet foods include duplicate copper ingredients; they both include Copper Sulfate and Copper Proteinate.

With the help of a Secret Shopper, we asked numerous pet foods why they use duplicate minerals. Below are those responses. Non-disclosure requirements made by most pet food companies email does not allow me to tell you which pet food manufacturer provided each response.

This first response – I believe – is the true answer to why duplicate minerals are used so commonly in pet food. Cost.

“Chelated minerals (protein bound) are the preferred way to include minerals in pet food formulations because they are more easily absorbed. Chelated minerals are also more expensive. We use a combination of both chelated and nonchelated minerals in order to still provide high quality, absorbable nutrition while still keeping our product affordable.”

But not every manufacturer gave us the same response…

One manufacturer stated that the proteinated form of copper is “more pure and safe and overall better”, they use both Copper Proteinate and Copper Sulfate “to make sure when states test our copper, the sulfate makes sure we reach the 5 ppm. This way we satisfy both federal and state regulations.”

Another manufacturer used the minimum requirement for copper (in regulations) as the reason for duplicate minerals, also stating “We add both forms of this supplement to ensure that the required levels of copper are being met.”

Another company explained that some chelated or proteinated minerals are “fragile” and because of this their “nutritionist likes to back them up with non-chelated forms of the mineral, such as Copper Sulfate.”

Another manufacturer told us something completely different. They stated that Copper Sulfate was the best form – sharing it was “100% available” and suggested that chelated or proteinated forms of copper should not be “more than 20% of the total copper” in the pet food.

One manufacturer told us that the required level of copper in the pet food could not be reached with Copper Proteinate alone. They stated they could only reach the “right amount” by adding Copper Sulfate.

Note: Responses that stated both forms of copper were required to meet regulatory standards is not accurate information. As evidenced by the pet food below, several pet foods use proteinated minerals alone to meet nutritional requirements.

Newman’s Own Adult Dog Food Dry

Minerals: Zinc Proteinate, Iron Proteinate, Manganese Proteinate, Copper Proteinate, Cobalt Proteinate (Source of Chelated Cobalt), Sodium Selenite

And one manufacturer gave us a very detailed response: “The two types of copper supplementation in our foods come from copper sulfate and copper proteinate. Copper, because of its chemical properties can bind to numerous other chemical structures in the food. This affects how it is absorbed and utilized. The copper in the copper sulfate is unbound and thus usually binds to many other things. The copper proteinate is copper bound to a protein. This keeps it from binding to anything else and once in the blood stream the protein is removed and the copper more available for the bodies needs. Both form are 100% safe and have been proven to be effective sources of copper for the body. So we use both types to make sure we actually supply the body with what is needed.”

Lots of different reasons for duplicate minerals.

I asked the duplicate copper ingredients question to several trusted industry insiders. I was told without doubt, the proteinated (or chelated) minerals are best of the commonly used pet food supplements. Copper Sulfate is less expensive than Copper Proteinate (same for other minerals), science shows that proteinated or chelated minerals are easier for the pet to absorb/utilize. And all of these trusted sources told me that the use of duplicate supplements is definitely a cost/savings issue; companies are using duplicate supplements (some higher quality proteinated and some lesser quality) to save money.

As example – if a pet food manufacturer saved a mere $0.25 per 100 pounds of pet food by using a combination of higher quality and lesser quality supplements, they could save more than $100,000 a year (and this would be a smaller manufacturer’s savings).

Using some proteinated minerals and some regular minerals is not a violation of any pet food regulation – both forms of minerals are approved for use in pet food. My belief – based on all the information I received, is that duplicate minerals are used ONLY to lower the costs to produce the pet food and to provide the manufacturer a competitive edge on store shelves.

To me, for my pets – I believe lesser quality ingredients/supplements come with a risk. As example (with supplements), a few months ago I published the story of a Michigan Veterinarian that is trying to bring attention to the potential risks of the pet food ingredient copper sulfate. This veterinarian’s own dog died from copper accumulation in the liver he links to copper sulfate in the pet food. And since posting that story, I’ve heard from several pet owners whose own pets were diagnosed with copper accumulation in their liver.

Wishing you and your pet(s) the best,

Susan Thixton
Pet Food Safety Advocate
Author Buyer Beware, Co-Author Dinner PAWsible
TruthaboutPetFood.com
Association for Truth in Pet Food

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