Abstract Body: Introduction: Emerging evidence suggests a bidirectional relationship between diet and sleep, with diet serving as a potential determinant of sleep health. Indeed, dairy products may improve sleep by increasing endogenous melatonin production. Despite this, few epidemiological studies have investigated the association between dairy consumption and sleep health in the US population. Therefore, we conducted a cross-sectional analysis to evaluate the association between dairy product consumption (total and sub-types) and sleep health in a nationally representative sample of U.S. adults.

Hypothesis: Higher dairy intake will be associated with better sleep outcomes compared to lower intake.

Methods: Participants included 23,000 men and women aged ≥18 y (mean age 46.7±0.3 y), pooled from the 2005-2020 National Health and Nutrition Examination Survey (NHANES). Dairy intake, including total and specific sub-types, was estimated from at least one 24-hour dietary recall. We categorized average dairy intake as low, moderate, and high based on the distribution of intake of the entire cohort. Sleep duration on weekdays and trouble sleeping (yes/no) were obtained from self-reported questionnaires. Sleep duration was categorized as: ≤7 h, 7–9 h (reference), and ≥9 h per night. Survey-weighted logistic regression was used to evaluate dairy intake in relation to sleep outcomes, adjusting for sociodemographic and clinical factors, lifestyle choices, sugar and saturated fat intakes, and the healthy eating index.

Results: Mean total dairy intake was 1.76 cup eq/day. High total dairy intake was associated with lower odds of short sleep duration (OR_{high vs low}=0.88; 95%CI 0.78-0.99; P-trend=0.033) and trouble sleeping (OR_{high vs low}=0.86; 95%CI 0.75-0.98; P-trend=0.025). Those with high milk intake had 16% lower odds of short sleep duration, compared to those with low milk intake (OR_{high vs low}=0.84; 95%CI 0.76-0.94; P-trend=0.0019). Moreover, high intake of whole and/or reduced fat dairy was associated with lower odds of trouble sleeping (OR_{high vs low}=0.81; 95%CI 0.72-0.92; P-trend=0.0016).

Conclusions: Our findings suggest that dairy consumption is associated with better sleep health, specifically lower odds of having insufficient sleep and trouble sleeping. However, these associations warrant confirmation in longitudinal studies and clinical interventions to further address causality.