New Research Warns Millions of Dogs Are at Risk From Copper in Their Food — Here's What to Know

What New Research Found

A leading veterinary liver specialist at Cornell University is sounding the alarm: at least 12 million dogs in the United States, age nine or older, may be at risk for serious liver injury from a source most owners would never suspect — their daily kibble.

Dr. Sharon A. Center, an emeritus professor of internal medicine at Cornell's College of Veterinary Medicine, has published three new peer-reviewed studies in the Journal of the American Veterinary Medical Association (JAVMA) showing widespread risk of copper-associated hepatopathy (CuAH) in dogs fed commercial diets. Her findings suggest that many popular dog foods contain copper levels high enough to cause silent, cumulative liver damage over a dog's lifetime.

"What else do we need to clarify to initiate regulatory action?" Dr. Center asked in a recent interview, expressing frustration that despite mounting evidence, neither the FDA nor the pet food industry has moved to address the problem.

The Silent Threat in Your Dog's Bowl

Here's what makes copper-associated hepatopathy so concerning: dogs can accumulate toxic levels of copper in their liver and remain completely asymptomatic for years. Much like Wilson's Disease in humans, the copper builds up silently — until a stressor like illness, injury, or surgery triggers a crisis.

Dr. Center's research demonstrates a directly proportional relationship between the increase in commercial dog food brands starting in the 1950s and copper accumulation in canine livers. The problem has accelerated in recent decades with the introduction of copper chelates — newer mineral forms where copper is combined with organic molecules like gluconate or amino acids. These chelates are absorbed 10 to 30 percent more efficiently than older copper sulfate forms, meaning dogs are now absorbing even more copper from their food than they did a generation ago.

According to Cornell's Riney Canine Health Center, while dogs need about 1.8 mg of copper per 1,000 kcals, many commercial dog foods contain 6 to 10 mg per 1,000 kcals — sometimes even more. That's three to five times the recommended amount.

Which Dogs Are Most at Risk?

While any dog can develop copper-associated hepatopathy, certain breeds are genetically predisposed and face significantly higher risk:

• Labrador Retrievers — America's most popular breed is also one of the most susceptible
• Doberman Pinschers — including recent Westminster Best in Show winner Penny's breed
• Bedlington Terriers — have a well-documented genetic predisposition
• West Highland White Terriers — another breed with elevated risk
• Dalmatians, Skye Terriers, and Anatolian Shepherds — also show higher susceptibility

But Dr. Center's research suggests the problem extends far beyond predisposed breeds. Her estimate of 12 million at-risk dogs encompasses all breeds age nine and older — meaning senior dogs of any breed fed commercial diets may be quietly accumulating dangerous copper levels.

Why the U.S. Has a Unique Problem

One of the most startling aspects of this issue is the regulatory gap. The Association of American Feed Control Officials (AAFCO) sets a minimum copper level of 7.3 mg/kg in dog food — but the United States has no maximum limit on copper content.

Compare that to Europe, where the European Pet Food Industry Federation (FEDIAF) caps copper at 28 mg/kg. It's easy to find U.S. dog foods that exceed even that European limit, with some products containing copper levels well above what any regulatory body would consider safe.

The Pet Food Institute (PFI), the industry's trade association, has pushed back on calls for regulation. In a statement, a PFI spokeswoman said the organization "did not believe there was a definitive link between copper levels in pet food and copper-associated hepatopathy," emphasizing that copper is an essential nutrient for dogs.

Meanwhile, the FDA's Center for Veterinary Medicine has declined to comment directly on Dr. Center's studies.

Warning Signs Every Dog Owner Should Know

Because copper accumulation is often silent, many dogs show no symptoms until the condition is advanced. However, watch for these potential warning signs:

• Loss of appetite or unexplained weight loss
• Lethargy and decreased activity
• Vomiting or diarrhea
• Yellowing of the eyes, gums, or skin (jaundice) — a sign of liver distress
• Increased thirst and urination
• Abdominal swelling from fluid accumulation

If your dog shows any of these signs, especially if they're a predisposed breed or over age nine, contact your veterinarian immediately. The only definitive way to diagnose copper-associated hepatopathy is through a liver biopsy with quantitative copper assessment.

What You Can Do Right Now

The good news is that there are concrete steps every dog owner can take to protect their pet:

1. Check Your Dog's Food

Contact your dog food manufacturer and ask about the copper content per 1,000 kcals. Look for foods closer to the 1.8 mg/1,000 kcal recommendation rather than the 6-10 mg range common in many brands. Be wary of foods that list copper chelates (copper proteinate, copper amino acid chelate) high on the ingredient list, as these are more bioavailable.

2. Talk to Your Veterinarian

Ask about liver health screening, especially if your dog is over nine years old or belongs to a predisposed breed. A simple blood panel measuring liver enzymes (ALT, ALP) can flag potential issues, though a biopsy is needed for definitive diagnosis.

3. Consider Therapeutic Options

If your dog is diagnosed with elevated copper levels, your vet may recommend a low-copper prescription diet such as Hill's l/d or Royal Canin Hepatic Support. Additional treatments may include D-penicillamine (a copper-binding medication), zinc supplementation to reduce copper absorption, or antioxidants like SAMe (found in Denamarin) and vitamin E to protect liver cells.

4. Make Your Voice Heard

The USDA currently has an open comment period (Docket No. APHIS-2025-1000) on dog welfare regulations, with a deadline of April 20, 2026. While focused on breeding standards, it's an opportunity to advocate for stronger oversight of dog food safety. You can also contact the FDA's Center for Veterinary Medicine to urge action on copper limits.

The Bottom Line

Dr. Center's research represents a significant body of evidence that commercial dog food copper levels may be causing widespread, silent liver damage in millions of dogs. While the pet food industry and regulators have been slow to act, dog owners don't have to wait.

By understanding the risk, checking your dog's food, and working with your veterinarian, you can take proactive steps to protect your pet's liver health — potentially adding healthy years to their life.

At Sidewalk Dog, we believe every dog deserves an owner who stays informed about the latest health research. For more dog health news, safety tips, and resources to help you and your pup live your best lives together, explore our city guides and sign up for our newsletter.