Researchers explain why lactose intolerance could be haunting your sleep
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A survey of over 1,000 students reveals a clear link between lactose intolerance, digestive upset, and more frequent nightmares.
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Only around 5.5% believe food affects their dreams, but sweets and dairy are the top perceived triggers.
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Feeling gassy or in stomach discomfort at night seems to mess with sleep quality and increase the chances of disturbing dreams.
If youve ever blamed late-night pizza or cheese for a weird dream, youre not alone.
Researchers at Universit de Montral and MacEwan University dug into whether food especially dairy can really affect sleep and dreams.
They surveyed 1,082 students, asking about their eating habits, overall health, sleep patterns, dream recall, and any food intolerances or allergies to determine if there's a genuine link between dairy and bad dreams.
Nightmare severity is robustly associated with lactose intolerance and other food allergies, researcher Dr. Tore Nielsen said in a news release.
These new findings imply that changing eating habits for people with some food sensitivities could alleviate nightmares. They could also explain why people so often blame dairy for bad dreams!
The study
Participants, mainly undergrads around age 20, completed an online questionnaire between January and April2023. It covered:
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Personal info (age, gender, health conditions)
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Diet habits (evening eating, snacks, food choices)
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Any intolerances (lactose, gluten) or allergies
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Sleep quality (using the Pittsburgh Sleep Quality Index)
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Nightmare frequency and severity (using a trimmed-down Nightmare Disorder Index)
They also asked if students thought certain foods or late meals affected their sleep or dreams. Statistical analyses looked for connections between food, physical symptoms, sleep quality, and dream experiences.
The results
Heres a look at what the researchers found:
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Many feel food affects their sleep. About 40% believed that eating late or certain foods influenced their sleep; 25% thought it made sleep worse. But only 5.5% said food affected their dreams directly.
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Dairy and sweets get the blame. Among those few, most blamed desserts/sweets (31%) and dairy (22%) for weird dreams or nightmares.
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Lactose intolerance stands out. The strongest link emerged for students with lactose intolerance: they reported more GI symptoms (like gas or stomach pain), poorer sleep quality, and more frequent or intense nightmares. Statistical models showed GI discomfort acted as a bridge between lactose intolerance and nightmares meaning the digestive issues likely trigger sleep disturbances and, in turn, bad dreams. Other food issues like general food allergies or gluten intolerance also connected to dream concerns, but the link was strongest for lactose intolerance.
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Overall eating habits matter. Healthier eating patterns like less evening snacking and using hunger cues were tied to better dream recall. Less healthy habits late meals, disregarding hunger signals, and experiencing GI symptoms were linked to more nightmares and negative dream content.
Nightmares are worse for lactose intolerant people who suffer severe gastrointestinal symptoms and whose sleep is disrupted, said Nielsen. This makes sense, because we know that other bodily sensations can affect dreaming.
"Nightmares can be very disruptive, especially if they occur often, because they tend to awaken people from sleep in a dysphoric state. They might also produce sleep avoidance behaviors. Both symptoms can rob you of restful sleep.
What this means
If you suffer from lactose intolerance and find yourself waking up stressed after a disturbing dream, dairy late at night could be a culprit and not because of superstition, but because night-time stomach discomfort interferes with restful sleep.
For some, simply adjusting evening meals like avoiding dairy before bed might lead to calmer sleep and fewer nightmares.
We need to study more people of different ages, from different walks of life, and with different dietary habits to determine if our results are truly generalizable to the larger population, said Nielsen.
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.
Posted: 2025-07-07 20:57:45
