Macronutrient intakes in infancy are associated with sleep duration in toddlerhood

Background: Dietary composition has been associated with sleep indexes. However, most of the evidence is based on cross-sectional data, and studies in young children are lacking.
Objective: The aim of this study was to explore the longitudinal associations of macronutrient composition of the diet with sleep duration and consolidation (number of awakenings) in infancy and early childhood.
Methods: The study was performed in 3465 children from the Generation R Study, a population-based cohort study in the Netherlands. Mothers reported their childs food intake at 13 mo of age by using a validated food-frequency questionnaire and their childs sleep patterns at 2 and 3 y of age. We used nutrient substitution models to assess the associations of relative macronutrient intakes with sleep indexes and adjusted the models for sociodemographic and lifestyle factors.
Results: Isocaloric substitution of fat intake by protein or carbohydrate in infancy was associated with longer total sleep duration at 2 but not 3 y of age. For each 5% increase in energy intake of either protein or carbohydrate at the expense of fat, sleep duration at 2 y of age was longer by 6 min (95% CI: 0.4, 12 min) and 4 min (95% CI: 2, 6 min), respectively. Further exploration of macronutrient subtypes indicated no consistent differences between saturated or unsaturated fat and that intake of plant compared with animal protein or Trp did not explain the association of higher total protein intake with longer sleep duration at 2 y of age. Replacing unsaturated with saturated fat was associated with 7 min (95% CI: -13, -1 min) shorter total sleep duration at 3 y of age. Macronutrient intakes were not associated with sleep consolidation.
Conclusions: Our results suggest that the macronutrient composition of the diet is associated with sleep duration in young children. Future research should further study the causality of this association and explore the underlying mechanisms. J Nutr 2016;146:1250-6.