Systematic review of complementary and alternative nutritional interventions for improving sleep

Background. Sleep is an essential component of health; yet, more than 33% of Americans receive insufficient sleep. Nutritional interventions may improve sleep by acting upon neurotransmitters that regulate the sleep-wake cycle. The purpose of this study was to evaluate dietary interventions as a complementary and alternative method for enhancing sleep. Methods. Inclusion criteria were: (1) studies published between 2003 and 2014 (2) in databases MEDLINE, CINAHL & AltHealthWatch; (3) in English language; (4) that targeted the general population; (5) employed nutrition or dietary supplements as primary intervention; (6) applied any quantitative design; (7) and reported sleep-related outcomes. Results. Twenty-one studies met the criteria. Nutritional interventions for sleep assume three categories: (1) Macronutrient interventions manipulate carbohydrates, proteins, and fats to improve sleep. Acute consumption of high glycemic carbohydrates four hours before bed time enhances sleep. Diets high in carbohydrates shorten sleep onset, while diets high in protein improve sleep quality. Diets high in fat negatively influence sleep quantity. (2) Supplemental interventions incorporate dietary supplements to induce sleep. Magnesium and melatonin have undergone rigorous experimentation and appear efficacious. (3) Chrononutrition interventions synchronize meal timing with the body’s biological rhythms to facilitate sleep. Such interventions also examine the thermic effect of food on sleep latency. Conclusions. There is a paucity of research examining the effect of nutritional interventions on sleep. The majority of interventions were conducted with healthy sleepers. More research is required to optimize, and possibly conjoin, the three categories of nutritional interventions, with a focus on participants presenting primary sleep disorders.