This tasty piece of cheese may give you nightmares—literally

National Geographic

8 hours ago

A study of more than 1000 college students found that there was a strong association between nightmares and eating cheese, primarily among those with food allergies or lactose intolerance. Photograph by Rebecca Hale, National Geographic
Anecdotal claims that eating cheese before bed causes nightmares were once so prevalent that in 2005 the British Cheese Board sponsored a study on the matter.
For the week-long experiment, 200 volunteers (100 women, 100 men) reported what variety of cheese they ate before bed and what their dreams were like. Though the study (more public relations than science) was never published in a peer-review journal, the details were fascinating: Stilton cheese reportedly induced weird dreams, such as one about a vegetarian crocodile that wanted to eat human children. Cheddar, on the other hand, was associated with dreams of celebrities.
A hundred years prior, American cartoonist Winsor McCay made cheese the antagonist of his early turn-of-the-century comic strip. In Dream of the Rarebit Fiend, characters are plagued by bizarre, even nightmarish dreams, usually after eating Welsh rarebit, a mildly spicy cheese toast.
A study published this June in the journal Frontiers in Psychology has finally revealed clues for why certain foods might lead to more fretful sleep. In a survey of 1,000 participants, nightmares after eating cheese or dairy products were much more common in people who were lactose intolerant.
It makes sense that having such uncomfortable symptoms while sleeping could influence dreams, says Tore Nielsen, the study's lead author and a neuroscientist at Université de Montréal who studies dreams and nightmares.
'We know that pain influences dreams. We know that other body sensations—just touching a dreaming person—can enter into their dreams,' he says. 'These pathways for influencing dreams exist for sure.' How scientists studied certain foods and dreams
Nielsen's first paper examining food and nightmares published in 2015. Then, he asked 396 university students if they thought particular foods gave them bizarre or disturbing dreams. Almost 18 percent said food played a role, and dairy or cheesy dishes like pizza and poutine (the study was done in Canada) were named as the primary culprits.
Nielsen's recent study found a much smaller general relationship between food and dreams. Only 5.5 percent of those surveyed reported that their dreams or nightmares were caused by food.
'But that's only part of the results, because we don't really know how accurate these participants are in detecting specific cause, effect relationships,' says Nielsen. 'This is just an impression. And the impression could be based on folklore, mythology, even like just things that they picked up, or misattributions, you know, I eat something late, I'm gonna have bad dreams.'
Yet when the researchers analyzed data about gastrointestinal symptoms—bloating, gas, diarrhea, cramps, pain—they found a distinct link: the lactose intolerant participants with the worst GI symptoms had the worst nightmares.
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The study authors also collected data from what Nielsen calls a 'style of eating questionnaire,' and found that nightmares correlated with not paying attention to one's own feelings of satiety and using the clock rather than hunger to decide when to eat.
'Ignoring those bodily signals, especially, were associated with having nightmares,' Nielsen said. The general eating habits that affect sleep
In addition to the usual suspects—caffeine and alcohol—highly-processed foods, sugar, and refined carbohydrates can interfere with a good night's sleep, say Marie-Pierre St-Onge, director of the Center of Excellence for Sleep and Circadian Research at Columbia University.
Her research has shown that eating more fruits and vegetables can lead to less fragmented sleep, while more fiber, whole grains, and nuts are helpful for better sleep overall. Low-fiber diets and diets high in saturated fat, on the other hand, are associated with lighter, less restorative sleep with more frequent arousals.
And while a poor diet can cause poor sleep, too-little sleep can make it more challenging to maintain diet, according to research by Erica Jansen, a nutritional epidemiologist at the University of Michigan.
'When you bring people into the lab and deprive them of sleep, whether that's a whole night of sleep deprivation or you limit their sleep to four or five hours, they eat differently the next day,' she says. 'They eat more calories. They have higher cravings for energy dense foods. They choose to eat more refined carbs, more fats.'
The mechanisms behind this aren't clear, but Jansen says that hormones, such as leptin and ghrelin, which are known to influence appetite, are altered by poor sleep.
If an unhealthy diet leads to poor sleep, does it have anything to do with nightmares? Maybe.
Jansen speculates that waking up more frequently, a pattern associated with foods like cheese that are high in saturated fat, can disrupt the balance between REM (rapid eye movement) and non-REM sleep. Most dreaming is done during REM sleep, and you're more likely to remember a dream if you wake up in the middle of it, says Jansen: 'I think that one possible mechanism could be that people are waking up more, so therefore they're remembering their dreams more.'
If bad dreams are caused by a generally poor diet, and the nightmarish effect of cheese is limited mostly to the lactose intolerant, how did cheese get such a bad reputation?
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Lucy Long, academic folklorist, director of the non-profit educational group Center for Food and Culture, and author of The Food and Folklore Reader, speculates that the association between cheese with nightmares is a relatively niche and recent belief. The idea that cheese is responsible for bad sleep is not common in many cultures, and on the contrary, warm milk is often thought to ensure peaceful sleep, she says.
'When people say, 'Oh, it's folklore,' sometimes it's actually something that was created in popular culture or by marketing.'
It's possible that the idea that cheese causes nightmares simply owes its popularity to Winsor McCay and his Rarebit Fiend.