The relationship between diet and sleep in 2-y-old children: Results from Growing Up in New Zealand.

Objectives: This study aimed to examine the relationship between dietary practices and sleep in young children.

Methods: In this study, 2-y-old children (n = 6327) and their mothers were enrolled at birth and during pregnancy, respectively. The study obtained maternal demographic, health, and lifestyle data during late pregnancy. Parents reported the 2-y-old child's dietary practices on a food frequency questionnaire, as well as sleep duration and night-waking frequency. Measures of dietary intake quantified servings per day for each food group (grouped as low/moderate/high intake). Sleep measures were as inadequate sleep when <11 h sleep in a 24-h period and increased night waking when waking ≥2 times per night. Multivariable logistic regression analyses examined associations between toddler diet and sleep, which were described using adjusted odds ratios (ORs) and 95% confidence intervals.

Results: In this study, 2-y-old children (n = 6288) slept for a mean of 12.3 hours (standard deviation: ±1.5 hours) over a 24-h period, with 734 children (12%) getting <11 h of sleep in 24 h. Increased night waking occurred in 1063 children (17%). Compared with low intake, high soft drink/snack/fast food intake was associated with inadequate sleep (OR: 1.37) and increased night waking (OR: 1.34). High milk/cheese/yoghurt intake (OR: 1.55) was associated with increased odds of night waking, but moderate (OR: 0.81) or high (OR: 0.78) vegetable intake was associated with decreased odds of night waking. Exposure to screens (OR: 1.28) and heavy maternal cigarette smoking (OR: 2.20) were also associated with inadequate sleep and increased night waking, respectively.

Conclusions: At age 2 y, higher consumption of soft drinks/snacks/fast foods is associated with shorter, more disrupted sleep. Conversely, higher vegetable consumption is associated with less disrupted sleep. Dietary modifications may improve toddlers' sleep.