Nightmares could be triggered by what you eat

If you’ve ever blamed a slice of pizza or a bowl of ice cream for a restless night of sleep, you’re not alone – and you might be onto something.

A new survey of more than 1,000 Canadian college students links certain food sensitivities, especially lactose intolerance, to poorer sleep and a spike in unsettling dreams.

“Nightmare severity is robustly associated with lactose intolerance and other food allergies,” said lead author Tore Nielsen from the University of Montréal.

“These new findings imply that changing eating habits for people with some food sensitivities could alleviate nightmares.”

Tracking diet and dreams

Folk wisdom has long insisted that a heavy meal – or the wrong one – can wreck a good night’s rest. But solid data has been thin.

To dig deeper, Nielsen’s team surveyed 1,082 students at MacEwan University in Edmonton. They asked about eating, bedtime and wake-up routines, overall sleep quality, dream recall, and how often respondents suffered nightmares.

Next, the researchers zeroed in on eating patterns, known food allergies or intolerances, and any personal hunch that certain foods affect dreams.

Roughly one-third of participants reported frequent nightmares. Women were more likely than men to remember their dreams and to say they slept poorly. They also reported food intolerances almost twice as often.

About 40 percent of all students felt that late-night eating or specific ingredients influenced their sleep, while roughly 25 percent believed certain foods made their nights specifically worse.

Dairy blamed for sleep loss

Among those who pinned their sleep woes on food, sweets, spicy dishes, and dairy products topped the list of potential villains.

Yet the most consistent pattern emerged when researchers compared diagnosed food sensitivities to nightmare frequency.

Students who were lactose intolerant had more gastrointestinal discomfort at night, recalled more nightmares, and rated their sleep quality as poorer.

“Nightmares are worse for lactose-intolerant people who suffer severe gastrointestinal symptoms and whose sleep is disrupted,” Nielsen noted. “This makes sense, because we know that other bodily sensations can affect dreaming.”

The logic is straightforward. If undigested lactose creates gas and cramping, that discomfort can seep into the dreaming brain, morphing into threatening imagery and prompting abrupt awakenings.

Repeated interruptions prevent sleepers from cycling into the deeper, restorative stages of rest – and can reinforce a vicious loop of dread and disturbed sleep.

Distress signals in the brain

Only about 5 percent of students believed specific foods colored the tone of their dreams, but those few often put the blame on dairy or sugary treats.

Interestingly, a similar survey Nielsen ran 11 years ago found a larger share of students convinced that food shapes dreams.

The drop-off might reflect growing public awareness of food allergies. For example, people who know milk upsets their stomachs may simply avoid it at night, dulling any obvious link.

Still, the new results echo a broader scientific push to understand the “gut-brain axis,” the two-way communication network that lets digestive distress influence mood, cognition, and, apparently, dreamscapes.

Even modest belly rumblings can send distress signals northward, nudging the brain to script darker stories.

Can food really shape dreams?

Of course, correlation doesn’t prove cause. People who eat poorly may sleep poorly – but chronic sleep loss can also drive cravings for comfort foods. Stress, exercise, and genetics muddy the waters further.

Nielsen calls for controlled trials: volunteers would eat dairy or placebo snacks before bed while researchers monitor gut activity, brain waves, and dream reports.

“We are routinely asked whether food affects dreaming – especially by journalists on food-centric holidays,” Nielsen said. “Now we have some answers.”

Yet big questions linger. Do other intolerances, like gluten sensitivity, twist dream content? Are the effects different in older adults or in kids? And how does mental health, which can influence both diet and dreaming, intertwine with these findings?

Eat early to stop nightmares

While science sorts out the details, the advice is common-sense: if you know milk or cheese bothers you, avoid it late in the evening, especially if nightmares plague you.

For anyone prone to indigestion at bedtime, lighter, earlier dinners and a pause on sugary or spicy snacks can’t hurt.

More broadly, the study nudges sleep hygiene beyond blue-light screens and blackout curtains to include what (and when) we eat. Our digestive tract doesn’t clock out at night; its complaints can echo loudly in the dream theater.

Until researchers run those carefully controlled cheese-before-bed experiments, moderation in the kitchen remains the gentlest path to sweeter dreams – and quieter nights.

The study is published in the journal Frontiers in Psychology.

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