Samples of popular commercial dog foods contained “dangerous levels” of heavy metals, plastic contaminants, and acrylamide, a cancer-causing compound created when food is subjected to high heat, according to a new investigation, reports BritPanorama.
According to the Clean Label Project, which conducted the study, the levels of heavy metals and other contaminants found in dog food were “alarming,” as stated by the organisation’s executive director, Molly Hamilton. The Colorado-based nonprofit tests consumer products for purity and offers manufacturers a certified label if their commodities meet strict standards.
“Pet owners care for their dogs as deeply as parents care for their children,” Hamilton emphasized. “They should be able to buy dog food without worrying it might harm their pet.”
The report noted that dog foods contained three to thirteen times more heavy metals than human food tested over the past decade by Clean Label Project. These findings corroborate previous research conducted by veterinarian Dr. Joseph Wakshlag at Cornell University College of Veterinary Medicine, who was not involved in the new investigation.
“We wrote a paper in 2018 comparing the intake of heavy metals between people and dogs based on calorie consumption,” said Wakshlag. He found that compared to humans, dogs consume three to seven times the amounts of heavy metals daily.
Dry dog food, also referred to as kibble, exhibited the highest levels of heavy metals and other contaminants, followed by air- and freeze-dried dog food. Fresh and frozen dog foods contained the lowest levels, according to laboratory tests. However, the report did not release specific test results by brand or product name.
“Over 85% of dog owners feed dry foods to their pets, and most dogs are eating one type of dog food each and every day, often for their entire life,” Hamilton explained. “If dry dog food is all they consume, it’s possible the accumulation of heavy metals could be contributing to the higher cancer rate in dogs.”
Heavy metals are known to accumulate in a dog’s kidneys and liver, potentially leading to chronic disease. Research indicates exposure to lead and cadmium has been linked to canine cancer, which is a leading cause of death in dogs. Approximately one in four dogs will develop cancer during their lifetime, according to the American Veterinary Medical Association.
The Pet Food Institute, representing dog food manufacturers, stated it would review the Clean Label Report, affirming that “PFI and U.S. pet food makers are continuously monitoring to best support the health and safety of dogs and cats.”
Fewer contaminants in fresh and frozen dog foods
In its investigation, Clean Label Project purchased 79 samples of best-selling fresh and frozen dog foods, kibble, and air- and freeze-dried products. A federally certified laboratory conducted 11,376 tests for a variety of contaminants, including plastics and heavy metals.
Fresh and frozen dog foods, which have been mainstream since 2006, showed the least contamination. Lead and mercury levels in dry food were observed to be approximately 21 times higher than in fresh and frozen varieties, with kibble also containing over thirteen times more arsenic and six times more cadmium compared to fresh and frozen products.
“Fresh and frozen dog foods are at least 70% water, and water contains far fewer heavy metals than a highly condensed piece of kibble,” Wakshlag explained. However, he noted that dogs need to consume about three cups of fresh or frozen dog food to gain the same caloric and nutritional benefits as one cup of dry food, potentially increasing their exposure to heavy metals.
Further investigations have revealed that high levels of heavy metals were found in commercial dog foods, exceeding the maximum tolerated levels set by regulatory agencies. There are currently no specific safe lead levels listed for dogs by the US Environmental Protection Agency, complicating the assessment of risks.
Safety thresholds for all animal feed are established by the Association of American Feed Control Officials and the National Research Council. However, these thresholds do not cater specifically to dogs, as the prevailing assumption is that dogs have a higher tolerance for heavy metals compared to humans.
Despite this belief, there is little data to support it, with Dr. Wakshlag highlighting the lack of research into chronic exposure to toxins in dogs. “How chronic consumption of these contaminants at really high levels affects a dog? We don’t know,” he stated.
A solution proposed by Wakshlag is for pet food companies to routinely test their products for toxins and report findings to consumers. “But extensive analyses take time and money,” he cautioned, indicating that such measures may lead to increased prices for dog food.
Acrylamide and chemicals used in plastics
The report identified acrylamide levels in dry dog food as approximately 24 times higher than in fresh and frozen options, with one sample testing at 780 parts per billion. Wakshlag remarked he had never encountered such high levels and questioned the cooking methods or ingredients used.
Acrylamide forms in carbohydrate-rich foods when cooked at high temperatures. The chemical is deemed “likely to be carcinogenic to humans” and is also present in tobacco smoke and used in the production of paper and plastics. The US Agency for Toxic Substances and Disease Registry notes acrylamide can reduce fertility in male animals and has caused various cancers in others.
The investigation also assessed levels of two bisphenols — BPA and BPS — and a phthalate known as DEHP, confirming that dry dog food contained the highest levels. While studies directly correlating these chemicals to health impacts in dogs are lacking, DEHP has been implicated in global mortality from heart disease.
BPA has been associated with various health issues, including fetal abnormalities and cardiovascular diseases in adults. Its replacement, BPS, may have similar adverse effects on reproductive systems.
For pet owners concerned about contaminants, Hamilton advised maintaining composure and consulting with veterinarians regarding diet options. If sticking with dry food, she recommended rotating brands as a means to diversify their dog’s diet. “You wouldn’t want to eat the same thing every day for every meal,” Hamilton concluded.
As the narrative on pet food safety continues to unfold, the implications for consumer awareness and industry standards are increasingly pressing.
