The Physicians Committee for Responsible Medicine, a non-profit national medical ethics organization, welcomes Colorado State University's decision to discontinue a nutrition study for which the university had approved the killing of 17,766 animals. The study, funded by the U.S. Department of Agriculture and the university, allegedly examined the effects of legumes on the human gut microbiome. Public records show that the principal investigator had used 1,587 mice so far.
The experiments were funded with an initial grant of $498,500 from the U.S. Department of Agriculture (USDA). A subsequent cooperative agreement from the USDA, valid through December 31, 2025, provides for the joint assumption of ongoing costs with the university.
Over the past two months, the Physicians Committee wrote to Dr. Cassandra Moseley, vice president for research at CSU, and CSU President Amy Parsons, to express scientific and ethical concerns about the studies and to request an investigation into the necessity of killing thousands of animals. The non-profit also contacted the principal investigator directly.
"Nutrition studies examining the effects of a legume-rich diet on the gut microbiome and the consequences of noncommunicable diseases are ethically and effectively conducted with human volunteers," Janine McCarthy, the Physicians Committee's acting director of research policy, wrote in the letter to Parsons.
She also wrote that while the search for alternatives to animal testing is mandated by federal regulations and the university's Institutional Animal Care and Use Committee (IACUC), the search conducted by the researcher had been flawed. This resulted in the principal investigator not considering viable alternatives to animal use. The IACUC did not challenge the flawed search.
In response to a public records request from the Physicians Committee, the university wrote in an email to Ms. McCarthy on August 11, 2025, that the principal investigator had terminated the experiment on July 15, 2025, and that he had no active protocols for conducting animal testing.
"We are grateful that the CSU has reconsidered these experiments and decided to stop them," said Ms. McCarthy. "We hope that other universities across the country will follow this example, end animal testing, and switch to research approaches that are more precise, more cost-effective, and above all, more relevant to humans. We also call on the U.S. Department of Agriculture to stop funding animal testing for human nutrition and invest instead in modern, human-specific science."
