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How canine heart disease was linked to grain-free dog food

In 2018, the US Food and Drug Administration, following input from a group of veterinary researchers, began investigating whether the growing popularity of grain-free dog foods had led to a surge in potentially heart disease. fatal in dogs, dilated cardiomyopathy.

Dog food is displayed at a pet store in Westfield, Ind., on Tuesday, July 19, 2022. In 2018, the FDA began investigating whether the growing popularity of grain-free dog foods had led to a surge in a Life-threatening heart disease in dogs Four years later, the FDA hasn’t reached a conclusion, but the publicity surrounding the issue has curtailed the once-promising market for grain-free dog foods.

Michael Conroy / AP

Four years later, the FDA has found no firm link between diet and dilated cardiomyopathy. He has also not denied such a link, and the investigation is ongoing. However, the hype around this problem has curtailed the once-promising market for grain-free dog food.

Additionally, a tangled web of funding and industry interests appears to have influenced the origin, data collection and course of the FDA study, according to internal FDA records.

A six-month investigation by 100Reporters found that the veterinarians who prompted the FDA to consider the diet have financial and other ties to major sellers of grain-based pet foods. Additionally, agency records show that for the initial study, some veterinarians were instructed to submit only cases of dilated cardiomyopathy (DCM) involving grain-free, “exotic,” or “boutique” pet foods. Suppliers of ingredients used in grain-free dog foods have also put pressure on the FDA to protect their market.

Consequently, the conversation about DCM and grain-free foods is deeply divided, with each side claiming the other prioritizes industry relationships over scientific integrity and pet lives.

“This has become such an emotional issue,” said Dana Brooks, executive director of the Pet Food Institute, whose members produce the majority of pet food in the U.S. “We are struggling to even try to figure out what is going on.” .

Matter of concern

Grain-free pet diets became popular in the early 2000s and relied heavily on legumes, the seeds of leguminous plants, such as peas, beans and lentils. By 2019, grain-free kibble accounted for 43% of dry pet food sold.

Until 2017, the FDA saw one to three reports of DCM per year. But between January 1 and July 10, 2018, he received 25 cases. Seven reports came from a single source, animal nutritionist Lisa Freeman of Tufts University Cummings School of Veterinary Medicine, an FDA spokesman said. However, FDA records obtained under the Freedom of Information Act indicate that those reports may not have been fully representative of the cases seen at the Tufts clinic.

In a June 2018 email to FDA Veterinary Medical Officer Jennifer Jones, Freeman attached a document directing veterinarians to report cases to the FDA: “If the patient is eating any diet other than those made by well-known, reputable companies or if you’re eating in a boutique, exotic foods. diet without ingredients or without grains (BEG).

When asked if this could be perceived as selective selection data that would shape research, Freeman stated via Tufts media relations, “The protocol in that email was developed to assist veterinary cardiologists in early stages of research on possible associations and intended between diet and dilated cardiomyopathy”.

“I shared the protocol with the FDA to let them know what our clinical recommendations were for patients at the time,” Freeman wrote, noting that they “continue to study” any diet with DCM-related ingredients “regardless of manufacturer.”

In an email, an FDA spokesperson wrote: “FDA has never requested that cases of DCM reported to the agency be limited to certain types of diet. We welcome all reports of DCM with a suspected link to food, regardless of diet type.”

According to, Freeman has received funding from leading grain-based food vendors, including Nestlé Purina Petcare, Hill’s Pet Nutrition, and Mars Petcare, since 2002. His recent conflict of interest statements state: “Over the past 3 years, the Dr. Freeman has received research funding, sponsored speaking engagements, and/or provided professional services to Aratana Therapeutics, Elanco, Hill’s Pet Nutrition, Nestlé Purina PetCare, P&G Pet Care (now Mars), and Royal Canin.”

Industry funding is common in animal nutrition science. Freeman said he supports his research and has “transparently disclosed the sources of funding for the work he did on this topic.”

Two veterinary cardiologists, Darcy Adin of the University of Florida College of Veterinary Medicine and Joshua Stern of the University of California Davis School of Veterinary Medicine, also collaborated with the FDA.

Emails from a public records request indicate that in April 2018, Jones spoke with Freeman, Stern and Adin about grain-free dog food and DCM and requested spreadsheets with their clinical case data.

Adin has been involved in studies funded by Purina since 2018 and, since 2017, by the Morris Animal Foundation, an animal health charity created by Hill’s founder and chaired by a Hill’s employee.

Public relations for the University of Florida said that neither Adin nor the university received direct financial support from companies for these studies.

Stern has authored studies funded by the Morris Animal Foundation since 2011 and currently receives funding from the foundation.

“I fully understand the conflict of interest concerns with people funded by the pet food industry,” Stern said. “It’s hard to find a veterinary nutritionist who hasn’t done research for pet food companies.”

Purina, Hill’s and Mars did not respond to multiple requests for comment.

In July 2018, the FDA announced its investigation, noting that many of the 25 dogs diagnosed lacked a genetic predisposition to DCM. The common thread, she said, seemed to be a grain-free diet.

A year later, the FDA took the unusual step of naming 16 dog foods, nearly all grain-free, that appeared most frequently in its DCM case reports. “We’ve never seen anything like this before without a certainty of the cause,” Brooks said.

Joseph Bartges, a professor of animal nutrition at the University of Georgia, was not surprised to point out that the FDA flagged grain-free foods all along. “When you only look for what you want to see, you only see what you look for,” Bartges said. As of July 2020, reports of DCM numbered 1,100, likely as a result of the FDA encouraging people to report the disease,” Brooks said.

influential industry

Suppliers of ingredients for grain-free foods, in turn, organized forces to protect their market share.

In its 2019 annual report, the U.S. Dry Pea and Lentil Council said it “convinced the FDA to clarify its language about its concerns and minimize harm to the industry.”

In a 2019 letter to FDA officials, Sen. Jon Tester of Montana, one of the top bean-producing regions, complained that the agency’s “baseless warning” had hurt bean farmers. The following year, seven senators signed another letter to the FDA noting a possible “bias on the causation of this disease.”

The FDA has continually stated that DCM involves multiple factors. Shortly after that letter, Steven Solomon, director of the FDA’s Center for Veterinary Medicine (CVM), emphasized this point, describing DCM as “a scientifically complex and multifaceted problem,” adding that “we . . . They currently do not see this as a regulatory problem.”

An FDA spokesperson wrote that while it met with stakeholders, “Ultimately, all of FDA’s decisions and work are guided by science, data, and our public health mission.”

Regardless of the final findings of the investigation, sales of grain-free dry dog ​​food have fallen since June 2018 and are down $60 million from 2021 to 2022. Meanwhile, sales that include grains soared in 2019 and are up $700 million from 2020 to 2021.

Getting an answer about DCM will be difficult thanks to the complexity of the science and the influence of industry, said Marion Nestle, author of Pet Food Politics. “Everyone is trying to protect their market share.”

This article is an abridged version of an investigation produced by 100Reporters, a nonprofit investigative news organization, with financial support from the Fund for Investigative Journalism and legal guidance from the Reporters Committee for Freedom of the Press.

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