The Association between Timing of Dietary Macronutrient and Sodium Consumption and Sleep Duration and Quality

The objective of this study was to examine the association between the timing of dietary macronutrients and sodium intake and sleep quantity and quality This was a cross-sectional study that included 34 adults between 21 and 50 years of age. The main outcome measures were objective sleep measures assessed from 3 nights of wrist actigraphy including sleep duration, fragmentation, and wake after sleep onset (WASO), and one night of polysomnography (PSG), including rapid eye movement (REM) sleep, non-REM stage 2 (N2), stage 3 (N3), and WASO. Multiple linear regression models and linear mixed models were used to estimate the associations between sleep measures and dietary measures (carbohydrates, fats, saturated fats, proteins, and sodium). Dietary timing was examined in two ways: (1) the average amount of each nutrient consumed within three hours of sleep start, and (2) the interval between the final intake of each nutrient and sleep. Average fat intake within 3 hours of sleep was associated with greater WASO from PSG (β=4.48, p=0.01). No other associations were found between the macronutrients or sodium intake (p>0.05) within 3 hours of sleep and the sleep parameters from PSG or actigraphy. Similarly, no associations were found between any of the PSG or actigraphy sleep measures and the interval between final nutrient intakes and sleep with sleep duration. The study suggests that greater fat but not carbohydrate, protein, saturated fat, or sodium intake close to sleep may be associated with greater sleep disruption, however, no other associations were observed.