Is Cheese Giving You Nightmares?

For centuries, folklore and popular wisdom have linked poor eating habits and indigestion to nightmares and restless sleep. In A Christmas Carol, Ebenezer Scrooge at first dismisses the ghosts that torment him as mere dietary disturbances: “You may be an undigested bit of beef, a blot of mustard, a crumb of cheese, a fragment of an underdone potato,” he says to one spectral visitor. “There’s more of gravy than of grave about you, whatever you are!” Earlier, Benjamin Franklin lamented that “[I]ndolence, with full feeding, occasions nightmares and horrors inexpressible; we fall from precipices, are assaulted by wild beasts, murderers, and demons, and experience every variety of distress.” In the early 20th century, cartoonist Winsor McCay made his name with his “Dreams of the Rarebit Fiend” series, in which his protagonists suffers bizarre dreams and nightmares which they attributed to eating Welsh rarebit—a delicacy of spiced cheese on toast. A modest body of contemporary research has sought to explore the link between food and nightmares more empirically. The latest is a new study published in the journal Frontiers in Psychology—finding that if you want to get your z’s, you’d best limit the cheese. To conduct the current study, Tore Nielsen, a professor of psychiatry at the University of Montreal, and his colleagues surveyed 1,082 students at MacEwan University in Alberta. All of them completed a questionnaire about their diet, food sensitivities, sleep habits, dream recall, and more. The students reported how late in the evening they eat, whether they regularly snack without feeling hungry, and if they have any gastrointestinal symptoms, food allergies, or diet-related conditions such as lactose intolerance. They also reported how well they sleep and how often their sleep is disturbed by nightmares. Read More: What Doctors Really Think of Sleepmaxxing About 25% of people said that eating certain foods before bed seemed to worsen their sleep, while just over 20% said that some foods improved their sleep. Of the people who reported having more nightmares after eating certain foods, 31% attributed the bad dreams to consumption of desserts and other sweets, 22% pointed to dairy, 16% cited meats, and 13% blamed spicy foods. The most commonly cited medical condition linked to sleep quality was lactose intolerance—lending legitimacy to Scrooge’s “crumb of cheese” charge. Of the people who believed their diet was related to worse sleep overall, 30% were lactose intolerant. “Nightmares are worse for lactose intolerant people who suffer severe gastrointestinal symptoms and whose sleep is disrupted,” said Nielsen in a statement that accompanied the release of the study. “This makes sense because we know that other bodily sensations can affect dreaming.” One 2024 meta-analysis, for example, found that all manner of sensory experiences—including sounds, smells, flashing lights, physical pressure, and pain—can be incorporated into dreams when people are sleeping and investigators provide the stimulus. Food-related nightmares might also be linked to depression and anxiety, the researchers say; lactose-intolerance symptoms like bloating, cramping, and gas directly affect mood, which can carry over into sleep, powering bad dreams. The paper cites an earlier 2005 study by Nielsen showing that “dreaming is more emotionally intense and conflictual when abdominal cramping is at its worst,” including during menstruation. Read More: What’s the Least Amount of Sleep You Need to Get? When people eat can make a difference as well. Eating late in the evening or snacking up until bedtime is linked to an “eveningness chronotype”—essentially the state of being a night owl—which by itself has been associated with nightmares in earlier cited studies. Nielsen and his colleagues concede that their current work does not establish causation, with at least the possibility existing that bad dreams and poor sleep may lead to equally poor dietary habits, rather than the other way around. “Direction of causality in many studies of food and sleep remains unclear,” the authors write. Not all foods, of course, are linked to nightmares and sleep disruption, and some may even support better sleep. Close to 18% of people who regularly eat fruits reported better sleep, along with 12% of people who consume a lot of vegetables, and 13% of people who drink herbal tea. Nielsen does not believe the current research remotely closes the book on the food and sleep and dreaming link, seeing a need for a lot of future work. “We need to study more people of different ages, from different walks of life,” he said in the statement. “Experimental studies are also needed to determine if people can truly detect the effects of specific foods on dreams. We would like to run a study in which we ask people to ingest cheese products versus some control food before sleep to see if this alters their sleep or dreams.”