A new study of over 1,000 students has scientifically confirmed the old wives’ tale that cheese can cause nightmares, particularly for people with lactose intolerance. The research, published in Frontiers in Psychology, found a strong association between lactose intolerance and nightmare severity, potentially due to gas or stomach pain during the night affecting people’s dreams.
Dr. Tore Nielsen of Université de Montréal, the study’s lead author, stated that “nightmare severity is robustly associated with lactose intolerance and other food allergies.” The researchers surveyed students about their sleep quality, dreams, nightmares, and food tolerances, discovering that lactose intolerance was associated with gastrointestinal symptoms, nightmares, and low sleep quality.
About one-third of participants reported regular nightmares, with women being more likely to remember dreams and report poor sleep. Only 5.5% of respondents felt that food affected their dreams, but many of those who did blamed sweets or dairy for making their dreams more disturbing or bizarre. The researchers believe eating dairy activates gastrointestinal disturbance, and the resulting discomfort affects people’s dreams and sleep quality.
Nielsen explained that simple dietary interventions could potentially help people improve their sleep and overall health, offering a practical solution for those experiencing dairy-related sleep disturbances.
Source: https://www.sciencedaily.com/releases/2025/07/250701020653.htm