Consuming dairy products at night can give you nightmares.

New research reveals a surprising link between nightmares and dairy products, especially in people with lactose intolerance.

A survey of 1,000 students found that those who consumed milk/cheese before bed were more likely to have disturbing dreams, possibly due to digestive upset disrupting sleep. The findings suggest that stomach contents can influence dreams – and that late-night eating has a deeper impact than just regular cravings.

Milk and Disturbing Dreams

According to a study published in Frontiers in Psychology , consuming a lot of milk can not only upset your stomach, but also disrupt your sleep. Scientists found a strong correlation between nightmares and lactose intolerance. Feelings of gas or bloating can 'intrude' into your dreams and disrupt deep sleep.

'Nightmare severity was significantly associated with lactose intolerance and other food allergies,' explains lead author Dr Tore Nielsen (Université de Montréal). 'This finding suggests that changing dietary habits in food-sensitive individuals could reduce the likelihood of experiencing bad dreams,' he says.

To explore the relationship between diet and sleep, the research team surveyed 1,082 MacEwan University (Canada) students about: sleep patterns, dream experiences, overall health and eating habits.

The results showed:

1. About one-third of students report frequent nightmares.
2. Women are more likely to experience poor sleep, remember dreams, and report food intolerances/allergies
3. About 40% believe that food or late-night eating affects sleep
4. 25% said specific foods made sleep worse

People with poor diets also tend to have more unpleasant dreams and remember their dreams less.

While the belief that food affects dreams has long been held, scientific evidence has been limited. This study helps fill that gap. 'We get asked all the time whether food affects dreams—especially by reporters around food-related holidays,' Nielsen says. 'Now we have an answer.'

Milk, sweets and carcinogens

Of those who said food disrupted their sleep, most blamed sweets, spicy foods, or dairy. Only 5.5% felt that food changed the 'tone' of their dreams, but within this group, many claimed that sweets/dairy made their dreams more bizarre or frightening.

When comparing reports of food intolerance with sleep quality, the researchers found that: Lactose intolerance was associated with digestive symptoms, nightmares, and poor sleep quality. The hypothesis is that milk triggers digestive upset, and this discomfort affects dreams and sleep quality.

" Nightmares are more severe in lactose intolerant people who have severe gastrointestinal symptoms and disrupted sleep ," Nielsen notes. " This makes sense because other bodily sensations can also influence dreams. Nightmares are significantly disruptive, especially when they occur frequently, because they cause people to wake up in a restless state, and can also lead to sleep-avoidance behaviors. Both of these interfere with restorative sleep ."

This may explain why the proportion of people reporting a food-dream connection in the current study was lower than in a previous survey of the same group by Nielsen and colleagues (Russell Powell, PhD) 11 years ago. Increased awareness of food intolerances may have led the students in the new study to avoid foods that triggered their symptoms, thereby reducing the impact on sleep. If so, a simple dietary intervention could potentially improve sleep and overall health.

However, beyond the clear link between lactose intolerance and nightmares, the mechanisms underlying the interaction between sleep and diet remain unclear. Nielsen concludes:

Further research is needed across diverse age groups, occupations, and dietary habits to determine the generalizability of the results. Experimental studies are also needed to test the ability to detect effects of food on dreams. We plan to conduct a trial in which participants are asked to consume a cheese product versus a control food before bed to assess the effects on sleep and dreams.

Jessica Tanner

Update 15 July 2025