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Melatonin plays a crucial role in managing the body's sleep-wake cycle, and its natural occurrence in certain foods has generated interest in dietary interventions to improve sleep. This scoping review explores the impact of consuming foods that naturally contain melatonin on various sleep quality parameters. The literature was obtained through four major databases: PubMed, Scopus, CINAHL, and Web of Science using PRISMA guidelines. A total of 19 articles were included, comprising 14 interventional trials and 5 cross-sectional studies. Key data were extracted on melatonin sources, dosages, sleep assessment methods, and reported effects on sleep. The quality of articles included was evaluated using the Joanna Briggs Institute (JBI) appraisal tools. The findings of interventional studies suggested that melatonin-rich foods, including Montmorency tart cherries, Jerte Valley cherries, tomatoes, and kiwifruit, may contribute to improvements in sleep quality, duration, and efficiency, particularly among individuals experiencing sleep disturbances; however, the findings remain heterogeneous. Observational studies also suggested possible associations between higher intake of melatonin-rich foods and favorable sleep-related outcomes, including sleep quality, circadian rhythm regulation, and reduced social jetlag, although findings were heterogeneous across populations and study designs. However, studies were limited by variability in population, timing of consumption, melatonin dosage, intervention duration, and sleep assessment tools. Most of the studies focused on a narrow range of foods, despite the increased availability of other melatonin-rich options that remain underexplored. Future research should prioritize the use of objective tools to assess sleep and investigate a more diverse range of dietary melatonin sources to gain a better understanding of their potential role in sleep regulation.…

PMID: 42058225

<h4>Background</h4>Dietary melatonin, naturally occurring in plant- and animal-based foods, has been linked to beneficial effects on sleep, mood and metabolic health. Although evidence suggests that food-derived melatonin may elevate circulating levels, few studies have assessed its intake through habitual diets or explored associations with chronic disease outcomes in adults.<h4>Methods</h4>We conducted a cross-sectional analysis within an open cohort of university graduates (baseline data). Dietary intake was evaluated using a validated 144-item Food Frequency Questionnaire (FFQ), and melatonin intake was estimated based on published concentrations. Sleep duration was also assessed through the questionnaire. Associations between dietary melatonin and selected health outcomes, including depression, obesity, hypertension, type 2 diabetes mellitus, metabolic syndrome, dyslipidemia, obstructive sleep apnoea and sleep duration, were examined across quintiles of intake using logistic regression and Poisson regression models with robust variance, adjusted for potential confounders.<h4>Results</h4>Melatonin content was assigned to 82.6% of the FFQ items, with concentrations ranging from 0 to 169.9 ng/g. Among 8320 participants, most were women (67.7%), with a mean age of 35.9 ± 9.6 years; 48.1% were single. Mean dietary melatonin intake was 25554.7 ± 13876.2 ng/day. In multivariate models, obesity was inversely associated with melatonin intake in Q2 (IRR 0.81, 95%CI 0.69-0.96); Q3 (IRR 0.72, 95%CI 0.60-0.86) and Q4 (IRR 0.79, 95%CI 0.67-0.94). Depression was inversely associated in Q3 (IRR 0.79, 95%CI 0.67-0.93) and Q4 (IRR 0.79, 95%CI 0.67-0.94), suggesting a nonlinear dose-response pattern.<h4>Conclusion</h4>Dietary melatonin intake was inversely associated with obesity and depression, with a non-linear dose-response pattern observed for depression. No significant associations were found with other chronic conditions or sleep duration. Longitudinal and experimental studies are needed to confirm these findings and clarify underlying mechanisms.…

PMID: 41588582

Gene knockout has been a powerful technique to evaluate the physiologic role of selected gene products. Lexicon pioneered high-throughput gene knockout technology and went further in designing agents to inhibit products of gene expression. Two agents have entered late-stage development. Telotristat is an inhibitor of tryptophan hydroxylase (TPH), preventing the production of serotonin. Although this agent blocks the two isoforms of TPH, it does not cross the blood-brain barrier, thus avoiding central neurologic manifestations. It inhibits the peripheral production of serotonin, and in particular prevents serotonin action in the intestines, resulting in decreased peristaltic action. Lexicon successfully developed telotristat to treat carcinoid syndrome not responding adequately to somatostatin inhibitors. Sotagliflozin development proceeded from the observation that dual inhibition of SGLT2 in the kidneys and SGLT1 in the intestines resulted in increased renal glucose excretion, reduced early-phase glucose absorption, as well as increased blood levels of GLP-1 and PYY. Initial development efforts focused on type 1 diabetes and have shown reduced postprandial glucose levels, less tendency to hypoglycemia, and lower HbA1c. Several other SGLT2 inhibitors have been associated with increased frequency of diabetic ketoacidosis (DKA). In the type 1 trials, sotagliflozin-treated individuals experienced DKA at a higher rate than placebo-treated patients. The sotagliflozin development program has now been extended to trials on type 2 diabetes. Long-term clinical trials will determine the benefits and risks of the agent in comparison to other currently marketed SGLT2 inhibitors.…

PMID: 30880915

5-Hydroxytryptophan (5-HTP) is the intermediate metabolite of the essential amino acid L-tryptophan (LT) in the biosynthesis of serotonin. Intestinal absorption of 5-HTP does not require the presence of a transport molecule, and is not affected by the presence of other amino acids; therefore it may be taken with meals without reducing its effectiveness. Unlike LT, 5-HTP cannot be shunted into niacin or protein production. Therapeutic use of 5-HTP bypasses the conversion of LT into 5-HTP by the enzyme tryptophan hydroxylase, which is the rate-limiting step in the synthesis of serotonin. 5-HTP is well absorbed from an oral dose, with about 70 percent ending up in the bloodstream. It easily crosses the blood-brain barrier and effectively increases central nervous system (CNS) synthesis of serotonin. In the CNS, serotonin levels have been implicated in the regulation of sleep, depression, anxiety, aggression, appetite, temperature, sexual behaviour, and pain sensation. Therapeutic administration of 5-HTP has been shown to be effective in treating a wide variety of conditions, including depression, fibromyalgia, binge eating associated with obesity, chronic headaches, and insomnia.…

PMID: 9727088

Melatonin plays a crucial role in managing the body's sleep-wake cycle, and its natural occurrence in certain foods has generated interest in dietary interventions to improve sleep. This scoping review explores the impact of consuming foods that naturally contain melatonin on various sleep quality parameters. The literature was obtained through four major databases: PubMed, Scopus, CINAHL, and Web of Science using PRISMA guidelines. A total of 19 articles were included, comprising 14 interventional trials and 5 cross-sectional studies. Key data were extracted on melatonin sources, dosages, sleep assessment methods, and reported effects on sleep. The quality of articles included was evaluated using the Joanna Briggs Institute (JBI) appraisal tools. The findings of interventional studies suggested that melatonin-rich foods, including Montmorency tart cherries, Jerte Valley cherries, tomatoes, and kiwifruit, may contribute to improvements in sleep quality, duration, and efficiency, particularly among individuals experiencing sleep disturbances; however, the findings remain heterogeneous. Observational studies also suggested possible associations between higher intake of melatonin-rich foods and favorable sleep-related outcomes, including sleep quality, circadian rhythm regulation, and reduced social jetlag, although findings were heterogeneous across populations and study designs. However, studies were limited by variability in population, timing of consumption, melatonin dosage, intervention duration, and sleep assessment tools. Most of the studies focused on a narrow range of foods, despite the increased availability of other melatonin-rich options that remain underexplored. Future research should prioritize the use of objective tools to assess sleep and investigate a more diverse range of dietary melatonin sources to gain a better understanding of their potential role in sleep regulation.…

PMID: 42058225

<h4>Background/objectives</h4>Sleep is pivotal for recovery, immunity, and energy restoration; however, sleep problems exist in elite athletes. Nutrition and supplementation strategies can play both a positive and negative role in sleep quality and quantity. Elite athletes experience unique psychological and physiological demands above non-elite athletes and may require different nutrition strategies to promote sleep. Nutrient interventions and their effect on sleep in elite athletes is an emerging area, with further research warranted.<h4>Methods</h4>Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for Scoping Reviews and Joanna Brigg's Institute Reviewer's Manual for Scoping Reviews were utilised to assess the available evidence on nutrition strategies used to promote sleep in elite athlete cohorts, and we tried to identify the interventions that could be best researched in the future. NUtrition QUality Evaluation Strengthening Tools (NUQUEST) was used to enhance rigour and assess risk of bias in studies. The Paper to Podium (P2P) Matrix was used to offer practitioners practical recommendations.<h4>Results</h4>12 studies met the inclusion criteria for nutrition interventions or exposures to promote sleep in elite athletes. The median participant group size was 19 and study designs were considered together to ascertain potential sleep promoting strategies. Kiwifruit, Tart Cherry Juice and high dairy intake, limited to females, have demonstrated the highest potential to promote sleep in elite athletes, despite limited sample sizes. A-lactalbumin, carbohydrate pre-bed, casein, tryptophan, probiotic and meeting energy demands showed varying results on sleep quality in elite athletes.<h4>Conclusions</h4>Kiwifruit, Tart Cherry Juice and dairy consumption offer potential nutritional interventions to promote sleep in elite athletic populations, while protein-based interventions may have a ceiling effect on sleep quality when elite athletes are already consuming >2.5 g·kg^-1 body mass (BM) or are already meeting their sleep duration needs.…

PMID: 41150477

This narrative review explores the relationship between sleep and nutrition. Various nutritional interventions have been shown to improve sleep including high carbohydrate, high glycaemic index evening meals, melatonin, tryptophan rich protein, tart cherry juice, kiwifruit and micronutrients. Sleep disturbances and short sleep duration are behavioural risk factors for inflammation, associated with increased risk of illness and disease, which can be modified to promote sleep health. For sleep to have a restorative effect on the body, it must be of adequate duration and quality; particularly for athletes whose physical and mental recovery needs may be greater due to the high physiological and psychological demands placed on them during training and competition. Sleep has been shown to have a restorative effect on the immune system, the endocrine system, facilitate the recovery of the nervous system and metabolic cost of the waking state and has an integral role in learning, memory and synaptic plasticity, all of which can impact both athletic recovery and performance. Functional food-based interventions designed to enhance sleep quality and quantity or promote general health, sleep health, training adaptations and/or recovery warrant further investigation.…

PMID: 30979048

Workplaces offer a key setting for health improvement interventions, given their reach and potential to promote lasting behaviour change. While diet and physical activity (PA) are common targets, sleep remains an underexplored yet influential factor in employee health. This randomised feasibility trial evaluated the practicality and acceptability of a 14-week, remotely delivered sleep-enhanced intervention (SEI) integrating sleep, PA, and diet, compared with a standard intervention (SI) focusing on PA and diet only, with exploratory assessment of behavioural and health-related outcomes. Staff from a UK higher education institution (<i>n</i> = 28) with short sleep duration (<7 h) and elevated cardiometabolic risk were randomised to SEI or SI. Quantitative data included self-reported and objective measures of PA, sleep, diet, and anthropometry over 14 weeks. Feasibility outcomes (recruitment, retention, compliance) and acceptability were assessed through qualitative interviews informed by the Theoretical Framework of Acceptability (TFA). Recruitment targets were achieved with 82% retention and 84% adherence. The SEI group showed indications of improvement in PA, dietary behaviours, anxiety symptoms, and sleep hygiene, while both groups showed reductions in BMI and waist circumference. Qualitative data highlighted the value of personalised guidance, peer support, and accountability, but also noted that the SEI's complexity sometimes hindered adherence. The WHOLE trial demonstrates the feasibility and acceptability of a remotely delivered, holistic lifestyle intervention for UK employees. A phased or extended approach may enhance sustainability and engagement in future large-scale evaluations.…

PMID: 42325726