John Sharp, chancellor of the Texas A&M University System, on Wednesday took the extraordinary step of sending a public letter of complaint to Harvard University president Lawrence Bacow. At issue is what’s been called an ongoing “food fight” between researchers at both institutions over whether or not it's healthy to eat red meat.

Sharp's letter cites a recent article in JAMA that accuses several Harvard public health researchers of trying to strong-arm another journal into pulling papers questioning longstanding guidance on beef consumption.

As these matters "undermine the values espoused by your institution," they "must be corrected immediately," Sharp wrote to Bacow. Meanwhile he said, “I can assure you that Texas A&M’s research is driven by science. Period.” (Note: This story has been updated from an earlier version, which incorrectly identified Sharp as Texas A&M's president.)

Sharp’s note also includes a photo from a recent cardiology conference, supposedly of a graphic used by Walter Willett, professor of epidemiology and nutrition at Harvard's T.H. Chan School of Public Health. The image accuses Texas A&M and Patrick Stover, a vice chancellor and dean of agriculture and life sciences there who co-authored the meat study, of being aligned with "big beef." Rejecting that notion, Sharp told Bacow he hoped to “work together to resolve this problem.” Such a resolution “should include a serious assessment by Harvard” of its affiliation with the True Health Initiative, he said, “and a comprehensive ethical review into any Harvard faculty involved” with it.

True Health is a global, independent organization that seeks to promote healthy lifestyles and eliminate preventable diseases. Willett and his Harvard public health colleague Frank Hu sit on True Health's governing council and are discussed at length in the JAMA piece.

In closing, Sharp said that Texas A&M wants Harvard to “join us for a purely scientific approach to nutrition for the sake of public health and public trust and reject the politics and unethical actions" that "have sought to discredit science and interfere in the scientific process.”

According to JAMA, things got tense around September, when the Annals of Internal Medicine planned to publish a group of articles on beef consumption. You may have heard of them -- they made headlines for suggesting that red meat isn’t all that bad for you. More specifically, they said that the overall evidence linking beef eating to heart and other diseases is overstated to tenuous.

The articles received immediate criticism, including from the past chair of the American Heart Association’s nutrition committee, who called the research “fatally flawed.” Harvard's School of Public Health also released a statement against it, saying that the "new guidelines are not justified as they contradict the evidence generated from their own meta-analyses. Among the five published systematic reviews, three meta-analyses basically confirmed previous findings on red meat and negative health effects."

The True Health Initiative went a lot farther than that, though, JAMA says. The publication accuses it of purposely breaking the meat papers' embargo and asking that they be censored, purposely flooding the Annals’ editor with complaint emails to the point that she had to shut down her account, and other behaviors unbecoming of academics.

“We’ve published a lot on firearm injury prevention,” Annals editor Christine Laine told JAMA. “The response from the NRA [National Rifle Association] was less vitriolic than the response from the True Health Initiative.”

Laine reportedly added, “It’s really frightening that this group, which includes people like Walter Willett and Frank Hu at the Harvard School of Public Health, which happens to be my alma mater, were aware of this and assisting it.”

Questions about conflict of interest emerged shortly after the meat papers' publication. Speculation centered on the lead researcher, from Dalhousie University in Canada, who responded that he had received funding from an industry trade group in 2015, outside of the three-year disclosure period. The new JAMA article, meanwhile, questions whether any of True Health's industry partners present a conflict of interest and questions the validity of some of the research it promotes. Ultimately, JAMA highlights the fact that nutrition research is notoriously difficult and open to criticism, as it tends to rely on human self-reporting about something as messy as diet over a long period time. Drawing nutritional guidelines from that research is even more difficult, the article points out.

Willett of Harvard said Wednesday that it's important to keep the focus of this story on health.

Nutrition is complex, he said, "and the perfect study is usually not possible for practical or ethical reasons, in part because disease like cancer, heart disease and dementia develop over many decades." The same applies to other important issues that can't be studied by randomized trials, "such as air pollution, climate change, environmental hazards and environmental chemicals," he added.

Still, Willett continued, through a combination short-term randomized trials concerning outcomes such as cholesterol levels or blood pressure and long-term observational studies, "we can learn much about aspects of diet that enhance or undermine health." Hu, Fredrick J. Stare Professor of Nutrition and Epidemiology at Harvard, did not provide immediate comment.

The True Health Initiative did not respond to a comment request. David L. Katz, head of the initiative and founding director of Yale University's Prevention Research Center, is quoted in the JAMA piece as saying that he and his colleagues only circulated the press release about the study prior to the embargo, not the papers themselves. And the initiative is not anti-meat, he said, just pro-science. In a lengthy post to LinkedIn on Wednesday, Katz and Sten H. Vermund, Anna M.R. Lauder Professor of Public Health and dean of Yale University's School of Public Health, responded to Sharp's criticisms, arguing that the question shouldn't be why there was opposition to the meat papers, but why there wasn't more opposition to them. Particularly concerning, they say, was some framing of the data as new providing "guidelines" about meat consumption. (Vermund is not associated with True Health.)

A Harvard spokesperson said only that Bacow received Sharp’s letter.

JAMA notes that 44 Farms, a producer of Black Angus cattle, established an endowment within Stover’s unit to support Texas A&M's International Beef Cattle Academy. But the beef industry provides only about 1.5 percent of AgriLife’s funding, Texas A&M says.