Is Dry Kibble Poisoning Your Dog, Or Is Study Fearmongering? What To Know

Is the kibble in the pantry shortening the family dog’s life?

A new study by the Clean Label Project warns consumers that its independent tests revealed multiple brands of dog food contain “alarming” levels of lead and other heavy metals, plastic contaminants, and acrylamide, a cancer-causing compound created when food is subjected to high heat.

Heavy metals can accumulate in a dog’s kidneys and liver and potentially contribute to chronic disease. Exposure to lead and cadmium has been linked to cancer, which kills about 1 in 4 dogs, according to the American Veterinary Medical Association.

The study raises questions about long-term exposure to these contaminants in pet diets, especially for dogs that are fed dry kibble every day. It garnered widespread media attention, leaving pet owners confused about the safety of respected brands among the 79 dog foods tested by the Colorado-based nonprofit.

The Clean Label Project said the findings are presented as a call for greater transparency and scrutiny of pet food contaminants, rather than an official health risk determination under regulatory criteria.

“I don’t think anyone, any group, any company, sets out to contaminate food,” Molly Hamilton, the CEO of Clean Label Project CEO Molly Hamilton told NBC News. “I think they love their dogs as much as I love my dog ... I think it just needs to have more attention brought to it.”

The Pet Food Institute, a national trade association, shot back in a statement, saying the study “risks misleading pet owners because it lacks essential scientific and regulatory context that is necessary for interpreting its claims that many dog foods in the United States contain harmful toxins.”

The U.S. dry dog food market is valued at approximately $20.9 billion to $23.6 billion, with kibble dominating the industry.

What The Study Showed

Clean Label Project testing found dry dog food had the highest levels of heavy metals, acrylamide, and bis(2-ethylhexyl) phthalate (DEHP), a colorless, oily liquid used primarily to make plastics flexible.

Because there are no comprehensive federal contaminant limits for dog food, the Clean Label Project compared results with human food data to highlight relative differences. Critics call that a flaw in the methodology.

Specifically, the testing showed:

• On average, arsenic levels were 5.7 times higher than those found in typical human food. Cadmium levels were 3.2 times higher on average than in human consumables, lead was 12.7 times higher, acrylamide was 24.1 times higher, and DEHP was 10.8 times higher.
• Air- and freeze-dried dog foods were a close second in heavy metals.
• The best choice for dogs is fresh or frozen food, which was “by far the lowest in heavy metals and lower than the average of our 3,280 human consumables.”

The report didn't provide individual results for each brand tested, but it does include a full list of products tested. To guide consumers, the Clean Label Project designated those that performed best with “Purity Award Product” and “Clean 16 Product” icons.

The bottom line, according to the Clean Label Project, is that dry dog foods, including air- and freeze-dried products, contained higher levels of heavy metals and other toxins than fresh or frozen food.

What The Pet Food Industry Says

The detection of trace heavy metals or other elements in food doesn’t equal toxicity, the Pet Food Institute said.

These elements occur naturally in soil, water, and crops and are found in both human and animal foods at levels far below those considered harmful. It’s practically impossible to make pet food with zero detectable trace elements.

Importantly, the industry trade group said, the report fails to disclose key information such as sampling methods, analytical protocols, established safety comparisons, and product-specific data. The data that is used appears to ignore the scientific requirement to account for product moisture levels when comparing fresh and dry pet foods.

Without transparency, the relevance of the reported levels to pet health cannot be assessed by consumers or veterinarians, the Pet Food Institute said.

The report also faces criticism because how much food the dog ate relative to its body weight wasn’t fully detailed in the summary. Some observers also note that because the report is from a nonprofit that offers product certification, its interpretation of data may be skewed.

What Other Research Shows

The Clean Label Project’s results were similar to those obtained in a 2018 study of 51 dry dog foods tested for arsenic, cadmium, lead, and mercury by researchers from the Cornell University College of Veterinary Medicine at Ithaca, New York.

Researchers said that compared to a person, dogs consumed three to seven times the amount of metals each day. But at the concentrations tested, “chronic toxic exposure levels are highly unlikely,” they concluded.

How Is Pet Food Regulated?

It’s important to remember, the Pet Food Institute said, that the pet food industry is among the most heavily regulated food industries in the country.

That’s not to say the safety and quality standards for human-grade recipes and animal feed-grade recipes are the same. Standards are looser for animal feed.

The Food and Drug Administration monitors trace elements in animal feeds to ensure they’re within maximum tolerated levels. Those levels are set by toxicity data and typical consumption rates, not just whether the element is present.

Trace metals likely come from ingredients like meat byproducts, added vitamin/mineral premixes, seafood, and plant-based carbs, according to the Clean Label Project. Kibble, designed for long shelf life, is a dry, preserved pellet. Multiple rounds of high-heat and high-pressure processing damage its natural nutrients.

Concerns are similar to those about ultraprocessed foods in the human diet. The more a product is processed and combined, the less nutritional integrity it has and the more likely it is to cause real harm.

Is Fresh Food Recommended?

Without long-term clinical evidence linking typical pet diets to health problems directly caused by heavy metals, there is no consensus among veterinarians about whether to feed dry dog food or a fresh alternative. The latter can easily cost more than $100 a month, versus cents a day for ultraprocessed kibble.

The cost isn’t one that can purely be measured in dollars and cents, according to the Clean Label Project.

Hamilton told NBC she doesn’t want to create a panic among dog owners but said the test results are enough to cause concern and warrant further study.

“These dogs are having the same food almost every day for their entire lives,” she told NBC News. “We need more studies to say, okay, the dogs that are getting sick, is diet playing a role?”

Consumers should educate themselves and insist that federal regulations catch up, Hamilton said, adding, “You know, that’s the beauty of independent consumer testing, is that you can say, I don't need the government to tell me how to get something better.”