Could your late-night cheese snack be haunting your dreams? New research suggests that dairy—especially in people with lactose intolerance—might be more than just a digestive trigger. It could also be fueling nightmares.
A study published in Frontiers in Psychology has found that individuals with more severe lactose intolerance symptoms reported significantly more intense and distressing nightmares. These findings build on earlier research from 2015 that explored how certain foods influence dreaming, commonly referred to as “food-dependent dreaming.”
“In the earlier study, people were blaming cheese all the time for their bad dreams,” said Dr. Tore Nielsen, professor of psychiatry at the University of Montreal and co-author of both studies. “Now, we’re beginning to understand why.”
The survey involved more than 1,000 participants, most of whom were undergraduate psychology students. Though the sample may not reflect the broader population, the results suggest a compelling link between dairy consumption, digestive discomfort, and poor sleep quality.
Participants who experienced the most severe gastrointestinal symptoms from dairy also reported the most disturbing nightmares — marked by intensity, frequency, emotional distress, and lasting impact.
Why Might Dairy Affect Dreams?
Experts believe several biological and psychological factors could explain this connection. Sleep researcher Dr. Marie-Pierre St-Onge from Columbia University notes that gastrointestinal discomfort alone can be enough to disrupt restful sleep, contributing to vivid or unsettling dreams.
“When you have GI issues, they can interrupt your sleep, causing micro-awakenings or sleep fragmentation,” St-Onge said. “That disruption may then influence the emotional tone or content of dreams.”
Dr. Patrick McNamara, a neurology professor at Boston University who studies the relationship between sleep and the brain, agrees. He notes that “micro-arousals” triggered by food sensitivities could reduce overall sleep quality, increasing the likelihood of experiencing nightmares.
Meanwhile, Nielsen points to anxiety linked with chronic digestive issues as another potential nightmare trigger. “Anxiety itself is well-known to influence sleep and dreams,” he said.
What This Means for Your Sleep Hygiene
While researchers caution that further studies are needed to replicate these findings in more diverse groups, the message for individuals is clear: your evening snack may be influencing more than your waistline—it might be affecting your rest and mental state, too.
Russell Powell, co-author and professor emeritus of psychology at MacEwan University, emphasizes that people can take simple steps on their own. “You don’t necessarily need a doctor to tell you to observe how your body reacts to certain foods and modify your diet accordingly,” he said.
As interest grows in how diet affects sleep, this research sheds light on an often-overlooked relationship. Until more is known, those with lactose sensitivity may want to skip the cheese plate before bed—for the sake of both their stomach and their dreams.
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