Tryptophan-rich diet can influence sleep quality in different phases of life

Resumen

 

Objective: To evaluate how the ingestion of tryptophan (food sources and supplementation) influences the circadian rhythm and sleep quality of humans and animals from different age groups. Methods: This is an integrative review of the literature conducted in PubMed and Capes Journals Portals, considering the period between 1998 and 2020 in Portuguese, English or Spanish languages. The guiding question was: "Does the intake of tryptophan through food sources and supplementation interfere with the circadian rhythm and quality of sleep?”. The following inclusion criteria were used: analysis of the descriptors (“tryptophan”, “diet”, “sleep”) in the title or abstract of the article; contextualization of the guiding question in the whole article; type of article and sample studied in the article. At the end, 12 articles were included in the study, eight of those having been carried out in humans and four in animals.  Results: All 12 studies showed that, when a daytime and/or nighttime tryptophan-rich diet, whether from dietary sources or supplementation, is administered to children (n = 2), adults (n = 6), adult animals (n = 2) and young and old animals (n = 2), a significant contribution to the synthesis of serotonin and melatonin took place. The presence of these mediators changed the chronobiology of the sleep-wake cycle, interfering with the quality of sleep of humans and animals. Conclusion: Foods that affect the availability of tryptophan – or its supplementation –  and the synthesis of serotonin and melatonin were able to organize the sleep of newborns, and improve sleep for adults and the elderly, regardless of the periods of the day. Thus, proposals for chronobiologically formulated diets with tryptophan may contribute to low-cost therapeutic approaches that would circumvent or reduce sleep disorders.