A new study suggests that excessive consumption of dairy products—especially if you are lactose intolerant—can disrupt your sleep and cause nightmares.

Researchers studied over 1,000 students and found a strong link between nightmares and food sensitivities, particularly reactions to dairy products.

The study, led by Dr. Tore Nielsen of the University of Montreal and published in Frontiers in Psychology, found that people who experience discomfort from dairy products, such as gas or stomach pain, may also have more disturbing dreams and poorer sleep. This discomfort at night can cause bad dreams and even wake people up feeling anxious.

The idea that food affects dreams is not new. For generations, people have believed that eating certain foods—such as cheese before bed—can lead to strange or frightening dreams. But scientific evidence for this is lacking.

To find answers, the research team asked students at McEwan University about their eating habits, sleep quality, and dreams. They also asked about their physical and mental health and how they personally believe food affects their sleep or dreams.

About a third of the students said they regularly had nightmares. Women were more likely than men to remember their dreams and report having sleep problems or nightmares. They were also almost twice as likely to report food intolerances or allergies.

Interestingly, about 40% of students believed that eating late or certain foods affected their sleep, and a quarter believed that some foods worsened their sleep.

People with unhealthy diets were more likely to have nightmares and less likely to remember their dreams. When asked what types of foods they thought worsened their dreams, the most common answers were sweets, spicy foods, and dairy products.

A small group—just over 5%—specifically mentioned that what they eat affects the tone of their dreams. Many of them blamed dairy products or sweet foods for making their dreams more disturbing or strange.

When the researchers looked more closely at students with food intolerances, they found that those with lactose intolerance had more stomach problems at night. These symptoms are strongly associated with nightmares and poor sleep quality.

Dr. Nielsen explained that this connection makes sense, as we already know that physical discomfort—such as pain or illness—can affect our dreams.

Nightmares are not only unpleasant—they can seriously disrupt sleep. They often wake people up suddenly and can make them anxious or afraid to fall asleep again. Over time, frequent nightmares can lead to long-term sleep problems and avoidance behaviors, such as staying up late to avoid falling asleep.

Interestingly, fewer people in this study reported a link between food and dreams compared to an earlier study by the same team more than 10 years ago. This may be due to the fact that people today are more aware of food intolerances and avoid foods that cause them problems—such as dairy products for those with lactose intolerance.

This raises an important question: if people know which foods upset their stomach or worsen their sleep, simple changes in diet could help them sleep better and avoid nightmares.

However, researchers caution that the link between food and dreams is not yet fully understood. It is possible that a poor diet leads to poor sleep—or that poor sleep leads to poorer eating habits. Or perhaps another hidden factor influences both.

The researchers say more studies are needed. They hope to test whether consuming dairy products such as cheese before bedtime actually changes people's dreams. They also want to study people of different age groups and backgrounds to see if the results are applicable on a broader scale.

For now, if you are prone to nightmares and are lactose intolerant—or sensitive to certain foods—it may be a good idea to change what you eat in the evening. A lighter and healthier dinner may be the key to better and more restful sleep. | BGNES