Thirty years ago it would have been difficult to imagine so many Americans rapt by a developing story about the relationship between our immune systems and legumes. But, here we are. Beyond addressing the immediate concerns of parents, the "epidemic" of peanut allergies tells the curious tale of why our bodies have rapidly begun rejecting one of the most clear-cut elements of a healthy diet—because, in part, we were trying too hard to be healthy.

In every major newspaper, on the morning shows and nightly news, yesterday's biggest story in health was about as big as health stories come. Peanut allergies—which appear to have quadrupled in the last two decades and now cost billions of dollars to accommodate—seem to be preventable with a simple, counterintuitive measure: eating peanuts.

The research at the center of the spotlight supports a compelling case that the practice of keeping peanuts out of infants' diets, just in case of allergies, has actually been helping to drive the national boom in peanut allergies. The new study, published in the esteemed New England Journal of Medicine, showed that when infants were regularly exposed to peanuts, by five years of age the children had a mere 3-percent chance of being allergic. By the same age, peanut-naïve children had an extraordinarily greater likelihood of developing an allergy: 17 percent.

“I’m kind of slapping myself on the wrist,” Ruchi Gupta, a pediatrician at Northwestern University, told The New York Times, lamenting withholding peanuts from her own baby daughter, who later tested positive for a peanut allergy. In 2000, the American Academy of Pediatrics recommended that peanuts not be introduced until age three. An ounce of prevention is worth a pound of cure, except when the prevention accidentally leads to a generation falling ill in the presence of a trace of bean dust.

New England Journal of Medicine

"The results have the potential to transform how we approach food allergy prevention," Anthony Fauci, director of the National Institute of Allergy and Infectious Disease, told USA Today. The idea that a lack of significant peanut exposure early in life is actually the reason that people develop allergies—because when the human body is not trained to recognize and tolerate certain elements in infancy, it develops an exaggerated immune response, an allergy, to those elements—is not a new one, either. But it bore out here in actionable and far-reaching ways. The American Academy of Pediatrics did update its guidelines in 2008 and 2011, but only to the point of saying that there was no clear evidence for withholding peanuts—not that they should necessarily be introduced.

So this week's study makes for a lovely story not just because peanuts, especially when buttered, are so widely adored. Like almost every great science story, it appears to turn conventional wisdom on its head: You've been doing this thing wrong! But don't worry; there is a simple solution! And, bonus, it involves eating. But when, exactly, should peanuts be introduced into an infant's diet? And how much does it take to prevent an allergy?

The researchers admit they don't know yet. But they also believe we don't have the luxury of waiting for more studies to find out the precise details. "The problem of the increasing prevalence of peanut allergy is so alarming," write doctors Rebecca Gruchalla and Hugh Sampson in an editorial accompanying the study, "new guidelines should be forthcoming very soon."

Popular media, though, will not wait for those guidelines to begin telling parents what they should do. More than narrative or nuance, actionability is what consumers of health media seem to want out of most stories. Which is always tricky. For the most part, coverage I've seen has been careful. But elements like Time's headline "The Surprising Way to Treat Peanut Allergies" and Kansas City's Fox News affiliate's "The Way to Drastically Reduce the Chances of Peanut Allergy in Your Child"—which concludes, "The research shows that introducing peanuts to baby is safe and drastically lowers the chance of the allergy"—underscore one important caveat.

Before anyone attempts to treat a peanut allergy with peanuts, note that the infants in this study who were found to have a strongly positive peanut allergy test at the outset were withheld from peanut exposure. They were not cured, nor attempted to be cured, of the condition. The study only applies to infants who had demonstrated no evidence of peanut allergy—or only a mild allergic reaction when given a skin test. It is rare to develop a peanut allergy during the first year of life, but not impossible.

For infants who prove to have a mild allergy, the advice of the researchers is to give them a little bit under the observation of a physician. For parents with any suspicion of an allergy, hereditary or otherwise, the advice is still not to give their infant any peanut products until a doctor can confirm the prudence of that move.

This is research that could turn out to have dramatic effects on parenting, pediatrics, and lives lived with(out) the social, culinary, and gustatory limitations imposed by food allergies. Most infants will tolerate and benefit from peanut exposure, it seems. But at least until the American Academy of Pediatrics and other expert bodies convene and rewrite guidelines, parents of infants who are, as the researchers write this week, "believed to be at risk for peanut allergy," should undergo skin-prick testing before eating anything containing peanuts. My colleague Adrienne LaFrance reported on the story deftly, ultimately deferring to individual decisions between parents and doctors: Ask yours before peanutting a child.

Overall, the story is one of science working as it is meant to work, self-correcting and embracing new evidence as it comes. Doing the best with the best knowledge available, and changing course readily, even when that means admitting to (well-intentioned) harm. The history of medicine is riddled with similar tales, and they should strengthen rather than undermine faith in the process.

And for the most part, the story is a study in consumer-health media as a driver of change: bringing important evidence to people who need not wait to hear about it from physicians. No doctor can possibly read every one of the thousands of journal articles published every week. At least in part because of the popularity of this study in patient-oriented media, no pediatrician will miss hearing about this and talking with parents about the best approach to the peanut-butter question—The Peanut-Butter Question (Random House or some such, Summer 2015-ish)—as soon as today.

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