Dubious nutrition research and downright terrible diet and health advice are nothing new, but the situation has devolved as of late. With the rise of anti-vaccine Health Secretary Robert F. Kennedy, federal food guidelines have centered on slabs of meat, excessive amounts of protein, and sticks of butter. The animal-based food craze has people slathering beef tallow on their faces. And, if your cardiovascular system isn’t already hardening just reading this, health influencers are now peddling nicotine—an addictive drug considered to be a cardiovascular toxin.
It is in this bananas context that headlines arrived in the past few days suggesting that eating fruits, vegetables, and whole grains can be bad for you. Specifically, it can supposedly increase the risk of lung cancer—a claim that flies in the face of decades of evidence-based nutrition guidance, like a full-fat cream pie.
The full study behind the headlines hasn’t been published yet, but experts have seen enough to call it baloney. The study is being presented at the American Association for Cancer Research conference this week and hasn’t been peer reviewed. Based on the abstract available online, the study was small, had no appropriate control group, led to a finding not previously hypothesized, used groupings that were “arbitrary,” is likely picking up on a known correlation, and jumps to speculation based on no data from the study.
“This is only a conference abstract, but the flaws of the study and its conclusions are quite striking,” Baptiste Leurent, associate professor in Medical Statistics at University College London, said in a statement.
A “stretch”
According to the abstract, researchers led by Jorge Nieva at the University of Southern California analyzed dietary survey data from 166 non-smokers who developed lung cancer under age 50. The researchers broke the participants into groups based on the mutations found in their cancers and scored the quality of their diets. Based on those scores, researchers found that the participants had higher scores for consuming fruits, vegetables, and whole grains compared with reference values for the general population. Without any more data, the researchers speculate that the produce and grains may contain high levels of pesticides, and those pesticides may increase the risk of lung cancer.
“Our research shows that younger non-smokers who eat a higher quantity of healthy foods than the general population are more likely to develop lung cancer,” Nieva said in a press release.
But Leurent and others immediately pointed out problems. First, there’s no control group, which should have included a similar group of non-smoking adults under 50 who do not have lung cancer. The finding “could simply reflect the fact that younger people, or non‑smokers, tend to have healthier diets than the general population,” Leurent said.
Multiple studies over the years, including meta-analyses and pooled studies, have found that eating fruits and vegetables either lowers the risk of lung cancer or has no effect.
Moreover, leanness—which a person may be on a diet heavy in fruits, vegetables, and whole grains—is known to correlate with lung cancer, Peter Shields, emeritus professor of Medical Oncology at Ohio State University, added. “The authors may not be seeing anything more than this.” Shields also called the mutation groupings “arbitrary,” and it’s unclear if they have overlapping carcinogenic pathways.
“And, even more important,” he continued, “a role for pesticides is entirely speculative.” Shields concluded that “the well-known benefits for eating fruits and vegetables … far outweigh any speculation of data interpretation from this study.”
Leurent equally dismissed the study, saying it was a “stretch” to link lung cancer to specific food groups, let alone pesticides that may or may not be on them. “Overall, this abstract provides little evidence of an association between diet and lung cancer, let alone any causal link, and offers no meaningful support for claims regarding pesticides,” he said.
