Dietary Protocols to Promote and Improve Restful Sleep: A Narrative Review

Humans spend approximately one third of their life asleep but, as counterintuitive as it may sound, sleep is far from being a quiet state of inactivity. Sleep provides the opportunity to perform numerous biological and physiological functions that are essential to health and wellbeing, including memory consolidation, physical recovery, immunoregulation, and emotional processing. Yet, sleep deprivation, chronic sleep restriction, and various types of sleep disorders are all too common in modern society. Failure to meet the recommended 7-9 hours of restful sleep per night is known to increase the risk of several health conditions, reason why regular and adequate sleep should be seen as a priority instead of an unnecessary commodity easily traded as required by the commitments of our busy lives. While both the quantity and the quality of sleep can be largely improved with relatively straightforward practices dictated by good sleep hygiene, emerging research suggests that dietary and supplementation protocols focused on certain foods, nutrients, and biochemical compounds with sleep-promoting properties can act as subsidiary sleep aids in complementing these behavioral changes. The scope of this narrative review is to summarize the available evidence on the potential benefits of selected nutraceuticals in the context of circadian rhythm and sleep disturbances, namely melatonin, magnesium, omega-3 fatty acids, tart cherry juice, kiwifruit, apigenin, valerian root, L-theanine, glycine, ashwagandha, myoinositol, Rhodiola rosea, and phosphatidylserine. A comprehensive recapitulation of the relevant literature is provided, alongside corresponding evidence-based nutritional protocols to promote and improve restful sleep.