Dreams have been explained in multiple ways: as your brain’s way of dealing with trauma or anxiety, per the Mayo Clinic; or as a message from your subconscious. But if your dreams aren’t pleasing, new science might highlight more evidence of the relationship between the gut and brain.

The Mayo Clinic points out that while anyone can experience a nightmare, a person with diagnosable nightmare disorder may experience frequent nightmares that induce possible distress, disrupted sleep, problems with daytime functioning, and fear of going to sleep.

So, in June 2025, Frontiers in Psychology published a study that set out to learn more about effects of certain foods on sleep. The research was led by doctors and scientists with the Dream & Nightmare Lab at Montréal North Island Integrated University’s center for sleep medicine.

For the study, 1,082 participants completed an online survey regarding their diets, food intolerances and allergies, personality questionnaires, measures of sleep quality (Pittsburgh Sleep Quality Index), the Nightmare Disorder Index (which screens for symptoms of nightmare disorder, per Sleep,) and participants’ own perceptions of specific foods on dreams.

The results indicated:

  • The participants’ “perceived effect of food on dreams” was linked to higher rates of remembered nightmares and Nightmare Disorder Index scores.
  • Of these participants, 31% attributed their nightmares to eating desserts or sweets, while 22% blamed their bad dreams on dairy.
  • Healthy eating was linked to better dream recall, while “unhealthy eating—including gastric symptoms, lower reliance on hunger and satiety cues, and evening eating—predicted nightmares and dream negativity.”
  • Nighttime eating was associated with poorer sleep quality and “more negative emotional tone of dream content”

The authors report that gastrointestinal symptoms from dairy may provide “one plausible basis for bizarre or disturbing dreams.” A possible explanation for this is that “GI symptoms increase nightmares by increasing symptoms of anxiety and depression.”

They add that individuals with allergies, intolerances, or sensitivities to certain foods may worry about accidentally consuming those triggers in ways that can increase generalized anxiety, too.

Tore Nielsen, PhD, the study’s lead author, said managing the G.I. medical condition could help: “Controlling the severity of lactose intolerance could be used to lessen the severity or prevent nightmares,” Dr. Nielsen told Medical News Today.

Meanwhile, for nighttime snackers, the findings related to nighttime eating, dream content, and sleep quality could also speak to sleep and psychological benefits of nighttime fasting until morning.

Per the Cleveland Clinic, people who are lactose intolerant “lack the enzyme they need to break down lactose, the sugar in milk.” Symptoms can include bloating, gas, nausea, vomiting, stomach pain, and diarrhea.

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Emily Surpless
Emily has over a decade of experience producing digital content, working on sites focused on health, lifestyle, home, and entertainment. As the editor for The Healthy by Reader’s Digest, she focuses on pitching and optimizing content to satisfy reader curiosity and reach new users. Prior to her role at The Healthy, Emily was the Sr. SEO Manager ...
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