Another Week, Another Nutrition Axiom Upended: Is Eating Meat Unhealthy?

For years, nutrition experts have warned that eating red meat can be bad for your health. Then a multi-part meta-analysis, published this week in the journal Annals of Internal Medicine, concluded that red meat may not be so harmful after all.

The fighting began almost immediately.

The 14-person research panel, which included collaborators from seven countries, conducted four “parallel systematic reviews that focused both on randomized trials and observational studies.” The team weighed the evidence for how red meat consumption affects rates of heart disease and cancer. They then voted on a final set of recommendations. For both processed and unprocessed meat, the group ruled, there was not enough health evidence to recommend that people cut back their consumption. (The question around the environmental impacts of meat consumption, they acknowledged, was a different question).

Within hours, a team of experts at Harvard’s T.H. Chan School of Public Health had published a point-by-point challenge to the study’s conclusions, urging people to continue limiting their red meat consumption. In an interview with a local TV station, Harvard nutritionist Walter Willett called the study’s conclusion “bizarre.” The New York Times documented the heated response to the study from experts, even as the researchers defended their methods — and stressed their lack of financial or industry conflicts.

At stake here are larger questions about the credibility and communication of nutrition science. Everyone, it seems, has a stake in nutrition results: researchers, doctors, nutritionists, farmers, and food industry representatives, not to mention all of us who eat food and worry about death. Into that high-stakes swirl comes nutrition science itself, which relies almost exclusively on large-scale observational studies. Those studies produce messy, conflicting data that’s often open to multiple interpretations, or that’s easily skewed to meet certain ends.

The result can be a mix of public confusion and frustration, to the point where, some experts and analysts say, it is time to recognize that nutrition science is broken.

Amid this week’s news, though, one stakeholder found more straightforward good news. On its Facebook page, the North American Meat Institute, an industry organization, shared the paper’s results, announcing that it was “the most rigorous study ever conducted on evidence for/against the health impacts of red meat.”

Also in the news:

• Zantac, along with several generic versions of the popular heartburn medicine, were pulled from pharmacy shelves late last week, after the Food and Drug Administration warned that recent sample testing had detected low levels of a known carcinogen. The FDA’s announcement prompted major retailers, including CVS, Rite Aid, and Walgreens, to remove all versions of the drug, known as ranitidine, from store shelves while the FDA and drug makers investigate safety concerns. The FDA said it found low levels of a contaminant called nitrosodimethylamine, or NDMA, which can form during manufacturing if chemical reactions used to make the drug are not carefully controlled. NDMA is believed to cause cancer in humans. Most pharmaceutical companies that produce and distribute ranitidine, including Sanofi, the maker of brand-name Zantac, have not issued recalls of their products in the United States. Instead, most have suspended distribution. (New York Times)

• The San Francisco Estuary Institute and the 5 Gyres Institute released the results this week from “the first comprehensive study of microplastic pollution in a major estuary.” The effort, which took three years and cost $1.1 million dollars, involved collecting nearly 400 samples from around the San Francisco Bay and then analyzing the tiny particles — trillions of which enter the Bay each year — at a University of Toronto toxicology lab. According to The Los Angeles Times, the research indicates that tire particles contaminate waters 300 times more than other known pollutants, like microfibers and microbeads released when doing laundry or using beauty products. The study’s lead author, Rebecca Sutton, told The Times the findings have global implications that could apply anywhere cars go. In response, the Southern California Coastal Water Research Project plans to draw from the study’s original research methods to standardize how microplastics are measured in California to better inform statewide environmental policies. (The Los Angeles Times)

• As evidence for the link between repeated head trauma, concussions, and neurodegenerative disorders like chronic traumatic encephalopathy (CTE) becomes ever stronger, football organizations at all levels have found themselves contending with a growing public health — and public relations — nightmare. The crisis has led to a boom in “anti-concussion” technology, from mouthguards and dietary supplements to chocolate milk and collars based on the supposed physiological mechanisms that prevent brain-rattling in woodpeckers. The problem, Christie Aschwanden reports this week for Wired, is that many of these techno-fixes are based on pseudoscience and none of them actually address the underlying physics of concussions. Any rapid acceleration or deceleration, not just direct blows to the head, can cause brain tissue to stretch and the player to experience a concussion, researchers say. Short of major changes to the sport’s rules, it may be tough for players to avoid sustaining head trauma. “How many things can you remove from football before you don’t have football?” one researcher wondered. “I don’t know the answer to that.” (Wired)

• As the U.S. moves to ban the sale of flavored e-cigarettes amid a vaping-related health crisis affecting more than 1,000 people around the country, documents obtained by The Los Angeles Times show that the Obama administration rejected a similar ban on flavoring four years ago. While the cause of the current health issues — which affect users’ lungs, and which have led to at least 18 deaths nationwide — is still being investigated, the majority of cases reported have been in e-cigarette users under the age of 25. According to the U.S. Food and Drug Administration (FDA), teen e-cigarette use has sky-rocketed in recent years, with usage among high school students increasing 78 percent from 2017 to 2018. The agency cites flavors as one of the top reasons for the products’ appeal to youth. After the FDA proposed the original ban in 2015, more than 100 lobbyists and advocates met with White House officials, pressuring them to shelve the proposal. A cost-benefit analysis determined the health benefits would not outweigh the burden on industry, and administration officials did not support the proposal. But today, said Matthew L. Myers, president of the Campaign for Tobacco-Free Kids, it’s clear that was a mistake: “The failure to ban these egregious flavors more than three years ago literally opened the door to what was an entirely preventable explosion in youth addiction.” (The Los Angeles Times)

• NASA Administrator Jim Bridenstine and SpaceX CEO Elon Musk have exchanged sharp words over lengthy delays to the Commercial Crew program, a partnership with SpaceX and Boeing that aims to develop spacecraft that could carry American astronauts to the International Space Station. The $6.8 billion contract was expected to be completed by 2017, but so far neither contractor has delivered, and, in 2020, NASA is anticipating having to purchase a ride for its astronauts on the Russian Soyuz spacecraft, at a cost of $85 million per seat. Following SpaceX’s announcement of their Starship rocket, an unrelated project, Bridenstine took to Twitter to complain that “Commercial Crew is years behind schedule. NASA expects to see the same level of enthusiasm focused on the investments of the American taxpayer. It’s time to deliver.” Musk responded during an interview with CNN Business shortly afterwards, joking “Did [Bridenstine] say ‘Commercial Crew’ or ‘SLS’?” Musk was referring to NASA’s planned Space Launch System, a heavy lift rocket intended to return astronauts to the moon, which is also far behind schedule. Bridenstine soon shot back. “Well, I don’t think that’s helpful”, he told The Atlantic. “SLS, that’s a whole different mission. SLS is going to the moon. So I don’t know why you would compare the two.” The two appeared to be mending their relationship, though — in a Thursday evening tweet, Bridenstine reported that he had enjoyed “a great phone call” with Musk and would visit a SpaceX facility next week. (Florida Today, The Atlantic)

• And finally, perhaps we aren’t born to run after all? That’s the conclusion of a strongly-worded essay by science writer Timothy F. Kirn, who traced the origins of an idea that was born in 1984 and has since become axiomatic among running enthusiasts. It’s the notion that certain traits characteristic of the human animal — principally the ability to efficiently dissipate body heat by sweating — evolved as a result of persistence hunting, or the act of chasing mammalian prey over long distances. Unlike humans, most mammals cool themselves by panting, a less efficient process that left them at a disadvantage when an unrelenting human predator stayed on their heels for miles — or so the theory goes. Eventually, the animals would collapse from heat exhaustion, and the human hunters would enjoy a feast. Surely this explained the modern human’s capacity for long-distance and endurance running, right? This just-so theory gained traction in the halls of academic science before gaining firm purchase in the popular culture through the 2009 book “Born to Run” — but Kirn argues that there’s one problem: There’s scant evidence that any of this is true, and even some seemingly clear-cut fossil evidence that flatly contradicts the idea. As for the persistent belief in the persistence-hunting theory, one paleoanthropologist called it “incredibly naïve.” (Undark)

Michael Schulson is a contributing editor for Undark. His work has also been published by Aeon, NPR, Pacific Standard, Scientific American, Slate, and Wired, among other publications.