Association of Sleep Quality and Macronutrient Distribution: A Systematic Review and Meta-Regression

Specific Nutrients Mediate the Association of Food Insecurity and Sleep Regularity Index (SRI) in U.S. Adults: NHANES 2011-2014

BACKGROUND/OBJECTIVES

Food-insecure individuals are at risk for poor health outcomes, including substandard sleep health. A possible association of food insecurity with sleep regularity has not been explored, and factors contributing to the relationship between food insecurity and sleep are not well understood. This cross-sectional study explored the relationship between food insecurity and sleep regularity and identified specific nutrients that mediated the association.

METHODS

This study used dietary intake, interview, physical examination, actigraphy, and laboratory data from NHANES 2011-2014 to assess the possible correlation between food insecurity and sleep in a sample of U.S. adults (n = 6730). Mediation analysis was conducted to determine specific serum biomarkers and intake of nutrients that indirectly contributed to the relationship.

RESULTS

Food insecurity was negatively correlated with sleep regularity. Dietary intake of fiber; vitamins A, B1, B2, C, E, and K; β-carotene; zinc; copper; and potassium and serum concentrations of palmitoleic acid had significant indirect effects on this association. The low/marginal food security group under-consumed vitamin K, and the very low food security group under-consumed vitamin K and zinc. Among food-insecure, income-eligible adults, those who received benefits from food assistance programs consumed significantly less fiber and β-carotene and exhibited significantly higher serum concentrations of palmitoleic acid than non-participants.

CONCLUSIONS

Food insecurity predicted sleep regularity, and this relationship was mediated by dietary intake and serum concentrations of specific nutrients, underscoring the role of nutrition security when evaluating potential health impacts for adults experiencing food insecurity.

Sleep Patterns and Tryptophan Consumption among Students at Spanish Universities: The Unihcos Project

The objective of this cross-sectional study was to explore sleep patterns and the potential relationship between sleep and tryptophan intake among Spanish university students. A total of 11,485 students self-reported their sleep and dietary patterns and habits. Tryptophan intake was calculated using a food intake matrix and results were presented as quartiles of total intake. Short sleep duration prevalence was 51.0%, with males exhibiting a significantly higher frequency. A total of 55.0% of participants presented inadequate sleep efficiency, with males again presenting a higher rate. Median tryptophan intake was 692.16 ± 246.61 mg/day, 731.84 ± 246.86 mg/day in males and 677.24 ± 244.87 mg/day in females (p = 0.001). Dietary tryptophan intake below the first quartile (<526.43 mg/day) was associated with a higher risk of short sleep duration in males (1.26; 95%CI: 1.02-1.55) and females (1.19; 95%CI: 1.05-1.34) and with the Athens Insomnia Scale insomnia in males (2.56; 95%CI: 1.36-4.82) and females (1.47; 95%CI: 1.10-2.05). Regarding academic specializations, females in the humanities field showed a higher risk of Athens Insomnia Scale insomnia due to low tryptophan intake (Q1: 3.15; 95% CI: 1.04-9.55 and Q2: 3.41; 95%CI: 1.01-11.5). In summary, lower tryptophan consumption appears to be associated with poorer sleep quality in Spanish university students; however, other social factors affecting students may also influence sleep quality. These findings have important implications for nutritional recommendations aimed at enhancing tryptophan intake to improve sleep quality.

Protein intake and its association with sleep quality: results from 3 prospective cohort studies

BACKGROUND/OBJECTIVES

Sleep quality is a critical factor for daytime functioning and chronic disease risk. We investigated the association between intakes of total protein and protein subtypes and sleep quality in three U.S. cohorts.

SUBJECTS/METHODS

In the Nurses' Health Study (NHS), NHS2, and Health Professionals Follow-up study (HPFS), dietary intake was assessed every 4 years using validated food frequency questionnaires. Sleep quality was measured once with the Pittsburgh Sleep Quality Index or adapted versions. With ordinal logistic regression, odds ratios (OR) and 95% confidence intervals (CI) were calculated to estimate the odds of having better sleep quality versus poorer sleep quality depending on protein intake (%Energy) based on the average of the prior two dietary questionnaires.

RESULTS

In 32,212 women from NHS, 51,126 women from NHS2, and 14,796 men from HPFS, total protein intake was not associated with sleep quality. However, the intake of protein from vegetable sources showed no association or a positive association with sleep quality (OR for quartile 4 versus quartile 1 in NHS: 1.12, 1.04-1.20, P-trend < 0.001; NHS2: 1.01, 0.95-1.07, P-trend = 0.90; HPFS: 1.11, 0.99-1.23, P-trend = 0.05), whereas divergent results were observed for animal protein sources. Overall, intakes of processed red meat and poultry were associated with worse sleep quality, whereas no or positive associations were observed for dairy and fish protein.

CONCLUSION

Our results suggest that plants as a source of protein may be associated with better sleep quality than animal sources of protein. Further studies are warranted to validate our findings.

Nutrition as the foundation for successful aging: a focus on dietary protein and omega-3 polyunsaturated fatty acids

Skeletal muscle plays a critical role throughout the aging process. People living with sarcopenia, a progressive and generalized loss of skeletal muscle mass and function, often experience diminished quality of life, which can be attributed to a long period of decline and disability. Therefore, it is important to identify modifiable factors that preserve skeletal muscle and promote successful aging (SA). In this review, SA was defined as (1) low cardiometabolic risk, (2) preservation of physical function, and (3) positive state of wellbeing, with nutrition as an integral component. Several studies identify nutrition, specifically high-quality protein (eg, containing all essential amino acids), and long-chain omega-3 polyunsaturated fatty acids (n-3 PUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), as positive regulators of SA. Recently, an additive anabolic effect of protein and n-3 PUFAs has been identified in skeletal muscle of older adults. Evidence further suggests that the additive effect of protein and n-3 PUFAs may project beyond skeletal muscle anabolism and promote SA. The key mechanism(s) behind the enhanced effects of intake of protein and n-3 PUFAs needs to be defined. The first objective of this review is to evaluate skeletal muscle as a driver of cardiometabolic health, physical function, and wellbeing to promote SA. The second objective is to examine observational and interventional evidence of protein and n-3 PUFAs on skeletal muscle to promote SA. The final objective is to propose mechanisms by which combined optimal intake of high-quality protein and n-3 PUFAs likely play a key role in SA. Current evidence suggests that increased intake of protein above the Recommended Dietary Allowance and n-3 PUFAs above the Dietary Guidelines for Americans recommendations for late middle-aged and older adults is required to maintain skeletal muscle mass and to promote SA, potentially through the mechanistical target of rapamycin complex 1 (mTORC1).

Association between self-reported food intake and subjective sleep quality among truck drivers in a city in Southern Brazil

Introduction

Sleep is an activity of great importance for maintaining the homeostasis of the human body and some components may interfere with the quality of sleep, including the pattern of food consumption. Truck drivers may constitute a population particularly sensitive to this association, since they are routinely exposed to situations that may interfere with food intake and sleep quality. Thus, this study investigated the association between self-reported food intake and sleep quality in truck drivers.

Methods

This was a cross-sectional study, with drivers who traveled in a city in southern Brazil. Food intake was evaluated through the average of food intake over the last 30 days. Food intake was evaluated in two forms: division in food groups and evaluation only tryptophan-rich foods. Sleep quality was measured by the Pittsburgh Sleep Quality Index (PSQI). In addition to the descriptive analysis, to identify possible associations between food intake and sleep quality, linear regression, crude and adjusted for confounding variables, were performed to obtain the Beta and Beta adjusted (Betaadj), respectively, and p-value.

Results

A total of 352 truck drivers, mostly males, mean age 48.4 (±11.6) years, with a frequent consumption of meat, fruits, vegetables, sweets, and energy drinks participated in this study. The frequent consumption of dairy products (Betaadj: --0.614. p-value 0.004) and fruits (Betaadj: --0.342. p-value 0.034) was associated with lower PSQI score, while the consumption of energy drinks was associated with a higher PSQI score (Betaadj: 0.923. p-value <0.001). The frequency of consumption of tryptophan-rich foods was not associated with sleep quality.

Conclusion

Fruits and dairy products are associated with better subjective sleep quality, while energy drinks are associated with worse sleep quality in truck drivers, whereas dietary tryptophan-rich foods intake was not associated with sleep quality.

A Systematic Review of the Bidirectional Association Between Consumption of Ultra-processed Food and Sleep Parameters Among Adults

PURPOSE OF REVIEW

We summarized research on the bidirectional association between intake of ultra-processed food (UPF) and sleep.

RECENT FINDINGS

Sleep contributes to cardiometabolic health in part via food intake patterns. Restricting sleep increases intakes of high-carbohydrate/high-fat foods, a profile representative of UPF. This systematic review covers the association of UPF intake, as an exposure or an outcome, and sleep. UPF was defined as NOVA Group 4. MEDLINE and EMBASE were searched through April 2023 for epidemiological studies with general-population adult samples. Fifteen studies met the inclusion criteria; all were cross-sectional, published between 2016 and 2023, with samples from Brazil (n = 8), Spain (n = 2), Italy (n = 1), the UK (n = 1), Paraguay (n = 1), Iran (n = 1) and China (n = 1). Thirteen studies examined UPF intake as the exposure whereas two tested UPF intake as the outcome. UPF intakes were determined using food frequency questionnaires (73%) or 24-h recalls (27%). Two studies assessed sleep via accelerometry; the remaining studies relied on self-reports of sleep quality, duration, anxiety-induced insomnia, and napping, with 60% using a single question. The average methodological quality across the studies was deemed "fair". Six of the 13 studies that examined UPF consumption as the exposure revealed inverse associations with sleep outcomes in adjusted (n = 5) or bivariate (n = 1) analyses. Both studies addressing UPF consumption as the outcome and sleep as the exposure showed significant inverse associations. Evidence for UPF-sleep associations is accumulating, although sleep assessment limitations are apparent. This review can provide impetus for research using comprehensive and validated sleep measures and nudge policymakers towards refining dietary guidelines worldwide.

The effects of low calorie, high protein diet on body composition, duration and sleep quality on obese adults: A randomized clinical trial

Background and Aims

The effects of high-protein diets on regulating sleep have received research attention in recent decades. However, no studies have examined the effects of these diets in obese adults. Therefore, this study was conducted to investigate the effects of low-calorie high protein diets on sleep quality in obese adults.

Methods

This study is a randomized clinical trial conducted on 60 obese adults (BMI > 29.9 kg/m2) diagnosed with low-quality sleep. All participants were given a diet with a 750-calorie energy deficit. While the control group was given a normal diet, the intervention group received a diet with 30% more protein.

Results

The results showed a significant difference between the control group and intervention group with respect to sleep apnea at 30-, 60-, and 90-day follow-up (p < 0.01). Sleep quality, apnea-hypopnea index (AHI), sleep latency (SL), and polysomnography were significantly different between the two groups (p < 0.05), showing an improvement in sleep quality and obstructive sleep apnea in the intervention group (p < 0.05).

Conclusion

This study shows that low-calorie high-protein diets can effectively improve apnea, sleep quality, and body composition indices in obese adults.

Association of oxidative balance score with sleep quality: NHANES 2007-2014

BACKGROUND

Oxidative stress is correlated with sleep quality. A common tool for evaluating dietary and lifestyle exposures to oxidative stress is the Oxidative Balance Score (OBS), with higher OBS suggesting more substantial antioxidant exposures. The relationship between OBS and sleep quality is unclear. Investigating the association between OBS and sleep quality was the purpose of this study.

METHODS

To figure out the relationship between OBS and sleep quality, we utilized weighted linear models and weighted logistic regression. Adjusted models were also examined.

RESULTS

6300 participants who took part in the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2014 were recruited. OBS was negatively associated with sleep disorder (OR: 0.97; 95 % CI: 0.94-0.99), and positively associated with sleep duration (MD: 0.02; 95%CI: 0.01-0.03). Within the range of OBS > 24, each unit increase in OBS will result in a 40 % reduction in sleep disorder, and a 26 % increasement in sleep duration after adjustment (all P for trend <0.05). Dietary and lifestyle components were closely related to sleep quality independently. The relationship between OBS and sleep quality was prominent in the female population under 50 years of age. After stratification by education level, this relationship persisted.

LIMITATION

This research was cross-sectional design, and it was not possible to deduce causality.

CONCLUSION

Diet and lifestyle might influence sleep quality by modulating oxidative balance. Antioxidant diets and lifestyles were important in reducing sleep problems and our study also provided new ideas for improving sleep quality.

Dietary amino acid intake and sleep duration are additively involved in future cognitive decline in Japanese adults aged 60 years or over: a community-based longitudinal study

BACKGROUND

Sleep duration and amino acid intake are independently associated with cognitive decline. This study aimed to determine the longitudinal association between sleep duration and cognitive impairment incidence and to examine the involvement of diet, particularly amino acid intake, in these associations in community dwellers.

METHODS

In this longitudinal study in a community-based setting, we analyzed data from 623 adults aged 60-83 years without cognitive impairment at baseline. Sleep duration was assessed using a self-report questionnaire. Amino acid intake was assessed using 3-day dietary records. Cognitive impairment was defined as a Mini-Mental State Examination score ≤ 27. Participants were classified into short-, moderate-, and long-sleep groups according to baseline sleep duration (≤ 6, 7-8, and > 8 h, respectively). Using moderate sleep as a reference, odds ratios (ORs) and 95% confidence intervals (CIs) of short- and long-sleep for cognitive-impairment incidence were estimated using the generalized estimating equation. Participants were classified according to sex-stratified quartiles (Q) of 19 amino acid intake: Q1 and Q2-Q4 were low- and middle to high-intake groups, respectively. Using middle- to high-intake as a reference, ORs and 95% CIs of low intake for cognitive impairment incidence were estimated using the generalized estimating equation in each sleep-duration group. Follow-up period, sex, age, body mass index, depressive symptoms, education, smoking status, employment status, sleep aids use, physical activity, medical history, and Mini-Mental State Examination score at baseline were covariates.

RESULTS

Mean follow-up period was 6.9 ± 2.1 years. Adjusted ORs (95% CIs) for cognitive impairment in short- and long-sleep groups were 0.81 (0.49-1.35, P = 0.423) and 1.41 (1.05-1.87, P = 0.020), respectively. Particularly in long sleepers (i.e., > 8 h), cognitive impairment was significantly associated with low cystine, proline, and serine intake [adjusted ORs (95% CIs) for cognitive impairment were 2.17 (1.15-4.11, P = 0.017), 1.86 (1.07-3.23, P = 0.027), and 2.21 (1.14-4.29, P = 0.019), respectively].

CONCLUSIONS

Community-dwelling adults aged ≥ 60 years who sleep longer are more likely to have cognitive decline, and attention should be paid to the low cystine, proline, and serine intake.

Low Sleep Hygiene Is Associated with Less Adherence to the Mediterranean Diet in Chilean Schoolchildren from Rural Public Schools-A Cross-Sectional Study

The Mediterranean diet stands as a widely acknowledged and health-promoting dietary pattern, renowned for its notable linkage to the mitigation of noncommunicable chronic maladies. Nonetheless, the existing body of evidence concerning the potential interrelation between sleep hygiene and this dietary regimen remains circumscribed. The main objective was to determine the association between sleep hygiene and adherence to the Mediterranean diet in Chilean schoolchildren from rural public schools in southern Chile. A non-experimental study was carried out, with an analytical, cross-sectional design. A total of 265 students (56.6% women, mean age 13.5 ± 1.8) from a rural community in southern Chile were recruited. Sleep habits were evaluated using Section 6 of the Life Habits and Adolescence Questionnaire, Sleep and Rest, and adherence to the Mediterranean diet was assessed with the KIDMED Mediterranean Diet Adherence Questionnaire. The main results indicated that 52.8% of schoolchildren need to improve adherence to the Mediterranean diet and 16.6% have a low-quality Mediterranean diet. A high percentage of schoolchildren have behaviors related to poor sleep hygiene (going to bed late (46%), waking up tired and wanting to continue sleeping (63.8%), and having problems falling asleep (42.6%)). Schoolchildren who got up after 8:30 a.m., those who fell asleep after midnight, upon conducting a comparative analysis of the students based on their sleep patterns, those who woke up tired and those who had trouble falling asleep had a lower level of adherence to the Mediterranean diet compared to schoolchildren who got up earlier than 8:30 a.m., fell asleep before midnight, did not wake up tired, and those who did not find it difficult to fall asleep, respectively. In conclusion, having poor sleep patterns including difficulties in both awakening and falling asleep are associated with less adherence to the Mediterranean diet in schoolchildren from rural public schools in southern Chile. Monitoring these variables and promoting healthy lifestyle habits within the educational community are essential measures.

The interplay between macronutrients and sleep: focus on circadian and homeostatic processes

Sleep disturbances are an emerging risk factor for metabolic diseases, for which the burden is particularly worrying worldwide. The importance of sleep for metabolic health is being increasingly recognized, and not only the amount of sleep plays an important role, but also its quality. In this review, we studied the evidence in the literature on macronutrients and their influence on sleep, focusing on the mechanisms that may lay behind this interaction. In particular, we focused on the effects of macronutrients on circadian and homeostatic processes of sleep in preclinical models, and reviewed the evidence of clinical studies in humans. Given the importance of sleep for health, and the role of circadian biology in healthy sleep, it is important to understand how macronutrients regulate circadian clocks and sleep homeostasis.

The relationship between the intake of branched-chain and aromatic amino acids and individuals' sleep quality based on body mass index, gender, and age

Sleep disorder is a relatively common problem that causes chronic conditions such as obesity, diabetes, and cardiovascular diseases. It is believed that diet regulates sleep. So, investigating the relationship between branched-chain amino acids (BCAAs) and aromatic amino acids intake with sleep quality based on age, gender and Body Mass Index (BMI) is important. A total of 172 males and females aged 18-65 participated in this study. The questionnaires were given online to them, included demographic information, food frequency questionnaire (FFQ), International Physical Activity Questionnaire, and Pittsburgh Sleep Quality Index. The Chalder fatigue scale (CFQ) was also used to measure the extent and severity of fatigue. The intake of amino acids was investigated by FFQ. The relationship between amino acids intake and sleep quality was investigated using Pearson's test. The results showed that intake of energy, macronutrients, and some micronutrients had a significant relationship with the quality of sleep of men compared to that of women (P < 0.05). No difference in sleep duration was observed between the two genders. There was a significant, positive association between sleep duration and the intake of BCAA (CC = 0.205, P = 0.031) and aromatic amino acids (CC = 0.22, P = 0.02) in the participants with normal BMI. Significant differences were seen in the intake of BCAA according to BMI which these differences were between lean and obese people, lean and overweight people, obese and normal, and overweight people. It demonstrated that in individuals with normal BMI, amino acids, protein, and carbohydrate intake may affect sleep duration and with modification of these factors sleep quality may get better. More study is needed to confirm these findings.

Nutritional geometry framework of sleep

AIMS

Sleep is a fundamental physiological function and is essential for all animals. Sleep is affected by diet compositions including protein (P) and carbohydrates (C), but there has not been a systematic investigation on the effect of dietary macronutrient balance on sleep.

MAIN METHODS

We used the nutritional geometry framework (NGF) to explore the interactive effects on sleep of protein (P) and carbohydrates (C) in the model organism Drosophila. Both female and male flies were fed various diets containing seven ratios of protein-to-carbohydrates at different energetic levels for 5 days and sleep was monitored by the Drosophila Activity Monitor (DAM) system.

KEY FINDINGS

Our results showed that the combination of low protein and high carbohydrates (LPHC) prolonged sleep time and sleep quality, with fewer sleep episodes and longer sleep duration. We further found that the effects of macronutrients on sleep mirrored levels of hemolymph glucose and whole-body glycogen. Moreover, transcriptomic analyses revealed that a high-protein, low-carbohydrate (HPLC) diet significantly elevated the gene expression of metabolic pathways when compared to the LPHC diet, with the glycine, serine, and threonine metabolism pathway being most strongly elevated. Further studies confirmed that the contents of glycine, serine, and threonine affected sleep.

SIGNIFICANCE

Our results demonstrate that sleep is affected by the dietary balance of protein and carbohydrates possibly mediated by the change in glucose, glycogen, glycine, serine, and threonine.

Exploring the Role of Dairy Products In Sleep Quality: From Population Studies to Mechanistic Evaluations

Poor sleep quality and insufficient sleep affect a large portion of the population. This is concerning given increasing evidence that poor sleep health is a behavioral risk factor for the development of cardiometabolic diseases. A healthy diet is associated with a plethora of favorable health outcomes, and emerging research now highlights diet as a potential determinant of sleep health that could be leveraged to improve sleep quality. Dairy products are notably rich in tryptophan (Trp), a key substrate for serotonin and melatonin production, which are instrumental for initiating and maintaining sleep. Furthermore, dairy products provide a range of micronutrients that serve as cofactors in the synthesis of melatonin from Trp, which could contribute to sleep-promoting effects. In this review, we evaluate population studies and clinical trials to examine a possible link between dairy consumption and sleep. Available epidemiologic studies illustrate positive associations between dairy intake and sleep outcomes. Moreover, some intervention studies support a causal effect of dairy intake on sleep. Given these data, we discuss potential mechanisms, invite additional clinical research on this topic, and provide insights on how limitations of current studies can be addressed in future trials.

Protein intake and its effect on sleep outcomes: a systematic review and meta-analysis of randomized controlled trials

CONTEXT

Poor sleep is increasingly seen as an issue of public health concern. In recent years, there has been growing interest in protein as a route to improve sleep outcomes; however, the evidence is limited and inconclusive.

OBJECTIVE

To examine, using a systematic review and meta-analysis, the effect of increased protein intake (≥1 g/kg//d, ≥25% of total energy intake, or protein supplementation of ≥10 g/d/) on sleep outcomes in adults.

METHODS

On November 30, 2021, 5 electronic databases were searched to identify relevant randomized controlled trials (PubMed, Cochrane, Embase, Web of Science, and CINAHL Plus). Risk of bias was assessed using the Cochrane Risk-of-Bias tool, version 2.0.

DATA EXTRACTION

Five sleep outcomes were included in this systematic review (sleep quality [SQ], sleep latency [SL], sleep efficiency [SEff], sleep time [ST], wake episodes, and other sleep outcomes) and 4 in the meta-analysis (SQ, SL, SEff, and ST). The quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach.

DATA ANALYSIS

Twelve intervention studies reported on in 10 articles were included. The qualitative analyses showed that increased protein consumption has little influence on sleep outcomes. Only subjective SQ was positively associated with protein consumption in a few studies. Meta-analyses also showed no significant effect of increased protein intake on sleep outcomes (number of studies for SQ, ST, SL, and SEff: 8, 8, 7, and 6, respectively), with very low certainty of evidence. However, results from sensitivity analyses, excluding high-risk studies, suggest a small effect on SQ in favor of high protein intake (mean difference, -4.28; 95%CI, -7.77, -0.79; on a scale from 0 to 100).

CONCLUSION

This systematic review and meta-analysis indicate there is no clear relationship between increased protein intake and sleep. However, the strength of the evidence is low and more randomized controlled trials that focus on this specific research question are warranted. Systematic Review Registration: PROSPERO registration no. CRD42020196021.

Intake of ultra-processed foods and sleep-related outcomes: A systematic review and meta-analysis

The aim of this review article was to evaluate the association between the intake of ultra-processed foods and sleep-related outcomes through a systematic review and meta-analysis. Pubmed, LILACS, Scielo, Scopus, Embase, and Web of Science were searched on December 31, 2021, for studies that evaluated the association between ultra-processed foods and sleep-related outcomes (self-reported sleep duration and quality). Pooled odds ratios were assessed through a random-effects model; heterogeneity was evaluated using the I² statistic. Fifteen cross-sectional studies were included; 14 showed that the high intake of ultra-processed foods was statistically significantly associated with sleep-related outcomes (sleep duration and quality). In the crude analysis, compared with low intake, high intake of ultra-processed foods increased the odds of sleep-related outcomes, with increased odds among children and/or adolescents, and null results among adults. When adjusted for cofounders, we found statistically significant results for all ages. The high intake of ultra-processed foods was associated with sleep-related outcomes, with moderate credibility of the evidence. Longitudinal studies and clinical trials confirming these findings are necessary.

Mediterranean Diet on Sleep: A Health Alliance

The Mediterranean diet is a plant-based, antioxidant-rich, unsaturated fat dietary pattern that has been consistently associated with lower rates of noncommunicable diseases and total mortality, so that it is considered one of the healthiest dietary patterns. Clinical trials and mechanistic studies have demonstrated that the Mediterranean diet and its peculiar foods and nutrients exert beneficial effects against inflammation, oxidative stress, dysmetabolism, vascular dysfunction, adiposity, senescence, cognitive decline, neurodegeneration, and tumorigenesis, thus preventing age-associated chronic diseases and improving wellbeing and health. Nocturnal sleep is an essential physiological function, whose alteration is associated with health outcomes and chronic diseases. Scientific evidence suggests that diet and sleep are related in a bidirectional relationship, and the understanding of this association is important given their role in disease prevention. In this review, we surveyed the literature concerning the current state of evidence from epidemiological studies on the impact of the Mediterranean diet on nighttime sleep quantity and quality. The available studies indicate that greater adherence to the Mediterranean diet is associated with adequate sleep duration and with several indicators of better sleep quality. Potential mechanisms mediating the effect of the Mediterranean diet and its foods and nutrients on sleep are described, and gap-in-knowledge and new research agenda to corroborate findings are discussed.

Effects of Dietary Carbohydrate Profile on Nocturnal Metabolism, Sleep, and Wellbeing: A Review

Sleep is a crucial biological function and a well-established driver of health and wellbeing across the lifespan. In this review, we describe how sleep in humans is associated with specific circadian metabolic and physiological changes, and how the organization of sleep-wake states is related to regulation of nocturnal metabolism during fasting. Among the modifiable factors that can contribute to sleep-related benefits, emerging evidence suggests that diet and nocturnal changes in glucose regulation are strong determinants of sleep quality. Here, we review studies that have explored the importance of quantity and quality of dietary carbohydrates and proteins in modulation of sleep and sleep-related health benefits. Future research may guide the creation of nutritional solutions to improve sleep, which could lead to positive changes in health, wellbeing, and overall quality of life.

Food consumption according to the level of processing and sleep quality during the COVID-19 pandemic

BACKGROUND AND AIMS

Consumption of ultra-processed foods is negatively associated with health outcomes, however, the contribution to sleep quality is limited. Therefore, the objective of this study was to evaluate the association between food intake by frequency and degree of processing and sleep quality in adults during the covid-19 pandemic.

METHODS

Population-based survey of adults from October to December 2020 in the Iron Quadrangle region, Brazil. The exposure variable was a food intake score that considered the frequency of consumption and food processing degree. The total score ranged from 0 (best) to 48 points (worst food quality), categorized into quartiles. Furthermore, we also evaluated whether individuals replaced their lunch and/or dinner based mostly on fresh/minimally processed foods for ultra-processed foods, for five or more days in the week. The outcome variable was sleep quality assessed with the Pittsburgh Sleep Quality Index. We constructed a contrasting directed acyclic graph (DAG) model to estimate the adjusted odds ratio of the association between score eating and sleep, by logistic regression.

RESULTS

Most of the 1762 individuals evaluated had poor sleep quality (52.5%). The minimum and maximum food scores were 0 and 30 points (mean 9.16; 95% CI 8.50, 9.81). The higher values of the score corresponded to lower consumption of fresh and minimally processed foods and higher consumption of ultraprocessed foods. In multivariate analysis, individuals in the third food consumption score had 71% greater odds of poor sleep quality (OR = 1.71; 95% CI: 1.03, 2.85) and in the fourth quartile 144% greater odds (OR = 2.44; 95% CI: 1.32, 2.44). Besides, replacing the dinner meal with ultra-processed foods five days or more in the week was also associated with poor sleep quality (OR = 2.01; 95%CI: 1.14, 3.57).

CONCLUSION

Higher consumption of ultra-processed foods concomitant with lower consumption of fresh and minimally processed foods is associated with a higher chance of poor sleep quality.

The Relationship Between Diet and Sleep in Older Adults: a Narrative Review

PURPOSE OF REVIEW

Older adults more frequently experience reduced sleep quality and quantity compared to younger adults. Diet is one modifiable lifestyle factor that may influence sleep outcomes in older adults. The purpose of this review is to synthesise the current literature investigating the impact of diet, including foods and nutrients, on the sleep quality and quantity of older adults.

RECENT FINDINGS

Overall, the observational and intervention studies suggest that following a Mediterranean diet, and the consumption of certain food items (e.g. milk), and nutrients (e.g. vitamin D and vitamin E) may influence (improve or reduce) sleep quality and quantity. This review describes the potential efficacy for dietary factors to improve sleep outcomes in older adults. However, given the heterogeneity of included studies in this review (i.e. aims, methodologies, and outcomes assessed), it is difficult to consolidate the available evidence to make specific recommendations. More targeted research exploring the relationship between diet and sleep in older adults is needed to strengthen the current evidence base.

Effects of macronutrient intake on sleep duration and quality: A systematic review

AIM

The aim of this systematic review was to characterise and synthesise the literature that explores the effects of macronutrient manipulation on sleep outcomes in order to provide dietary recommendations for sleep improvement.

METHODS

Intervention studies that evaluated the effects of macronutrient manipulations on sleep were identified using four databases. A study was included if it: (a) delivered a macronutrient-based dietary intervention, regardless of length; (b) included healthy human participants aged 18 and older; and (c) measured some aspect of sleep, for example, duration or quality, in some manner.

RESULTS

A total of 17 papers and 19 studies met the inclusion criteria. Included studies were organised into acute studies lasting less than 24 hours (n = 4), longer-term (≥24 hours) studies (n = 10), and energy restriction studies (n = 5). The greatest amount of support was observed for longer-term administration of higher carbohydrate diets. These interventions positively influenced rapid eye movement sleep; however, non-rapid eye movement sleep was negatively affected. The overall health outcomes of these changes are difficult to assess. Limited evidence suggests higher protein diets under conditions of energy restriction can improve sleep quality, but these effects might be restricted to individuals with overweight or obesity. Current evidence does not support the effects of acute macronutrient manipulation, defined as less than 24 hours, on sleep outcomes.

CONCLUSIONS

Manipulating carbohydrate intake for at least 24 hours appears to alter sleep outcomes among healthy individuals. Interventions were highly varied and methodological shortcomings were identified. More work is required to fully understand how macronutrient intake affects sleep outcomes.

Association between diet and sleep quality: A systematic review

Dietary habits are considered a leading behavioral risk factor for human health. There is growing scientific evidence suggesting that diet and sleep may be related. The aim of this study was to review the evidence of association between diet and sleep quality. A systematic search in electronic databases PubMed, Embase, Scopus, and the Cochrane Central Register of Controlled Trials was conducted from their inception to November 2019. Studies investigating parameters of diet quality (including dietary patterns or individual healthy/unhealthy foods) and sleep quality (assessed through self-reported or objective methods) were included. The NIH Quality Assessment Tools were used to evaluate the study quality. Twenty-nine studies were reviewed: in summary, consumption of healthy foods was associated with better sleep quality, while higher intake of processed and free-sugar rich foods was associated with worse sleep features. Despite a certain consistency between studies have been observed, the overall poor-to-fair quality of study design (mostly represented by cross-sectional investigations) does not allow to conclude a causal relation. However, diet-related variables are associated with sleep quality, but further studies are needed to corroborate this finding.

Improving sleep disturbances in obesity by nutritional strategies: review of current evidence and practical guide

Over the past decades, there has been an increase in overweight and obesity worldwide rates in both in adult and children. In parallel, it has been reported a worsening of sleep duration and quality. Some studies have shown an association between obesity and sleep disturbances (SD) vice versa, subjects with obesity have a greater risk of SD. As well as SD influences diet, also food choices have been shown to influence various sleep-related variables, such as duration and quality. For this reason, nutrition could represent an important tool not only to lose weight but also to improve sleep in patients with obesity and sleep disturbances. Thus, the aim of this review is to provide an overview of the studies that assessed the association between obesity and SD and vice versa, highlighting possible nutritional advices as a tool to improve sleep in patients with obesity and sleep disturbances.

Adults Who Are Overweight or Obese and Consuming an Energy-Restricted Healthy US-Style Eating Pattern at Either the Recommended or a Higher Protein Quantity Perceive a Shift from "Poor" to "Good" Sleep: A Randomized Controlled Trial

BACKGROUND

Limited evidence suggests that consuming a higher-protein diet during weight loss improves subjective indices of sleep in overweight and obese adults.

OBJECTIVE

We sought to a priori assess the effects of consuming the recommended versus a higher protein Healthy US-Style Eating Pattern during energy-restriction on sleep quality indices.

DESIGN

Using a randomized, parallel study design, 51 adults (mean ± SEM age: 47 ± 1 y; BMI: 32.6 ± 0.5 kg/m2) consumed a controlled USDA Healthy US-Style Eating Pattern containing 750 kcal/d less than their estimated energy requirement for 12 wk. Participants were randomly assigned to consume either 5 or 12.5 oz-equivalent (eq)/d of protein foods. The additional 7.5 oz-eq/d came from animal-based protein sources and displaced primarily grains. Objective (wrist-worn actigraphy) and subjective (Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale) sleep quality indices were measured at baseline, week 6, and week 12.

RESULTS

Among all participants, body mass decreased (-6.2 ± 0.4 kg). Dietary protein intake did not affect any objective or subjective sleep quality outcomes measured (repeated measures ANOVA). Over time, objective measures of time spent in bed, time spent sleeping, sleep onset latency, and time awake after sleep onset did not change; however, sleep efficiency improved (1 ± 1%; P = 0.027). Subjectively, global sleep scores [GSS: -2.7 ± 0.4 arbitrary units (au)] and daytime sleepiness scores (-3.8 ± 0.4 au; both P < 0.001) improved over time. The GSS improvement transitioned the participants from being categorized with "poor" to "good" sleep (GSS: >5 compared with ≤5 au of a 0-21 au scale; baseline 7.6 ± 0.4 au, week 12: 4.8 ± 0.4 au).

CONCLUSIONS

Although objective sleep quality may not improve, adults who are overweight or obese and poor sleepers may become good sleepers while consuming either the recommended or a higher-protein energy-restricted Healthy US-Style Eating Pattern. This trial was registered at clinicaltrials.gov as NCT03174769.

Associations between dietary inflammatory index and sleep problems among adults in the United States, NHANES 2005-2016

OBJECTIVES

To examine the associations between Dietary Inflammatory Index (DII) scores and sleep measures of sleep duration and self-reported sleep disturbance.

DESIGN

Cross-sectional study.

SETTING

The United States.

PARTICIPANTS

Participants from the 2005-2016 National Health and Nutrition Examination Survey (NHANES) who were 20 years old or older (n = 30,121).

MEASUREMENTS

Sleep duration, classified as short (≤6 hours), long (≥9 hours) and recommended (6-9 hours) duration, and the presence of self-reported sleep disturbance were the outcome variables. The energy-adjusted DII (E-DII) was computed based on the dietary intake data using a single-day 24-hour dietary recall. Multinomial logistic regression was used to examine the associations.

RESULTS

After adjusting for confounders, participants in the highest quintile (most proinflammatory E-DII) had a 40% increase in the odds of short sleep duration compared to the lowest quintile (most anti-inflammatory E-DII)(OR_quintile5vs1 = 1.40 [95% confidence interval {CI}, 1.21, 1.61]). The odds of short sleep duration was increased by 26% in quintile 4 compared to quintile 1 (OR _quintile4vs1 = 1.26 [95% CI, 1.10, 1.43]). Similarly, the odds of long sleep duration was increased in higher E-DII quintiles (OR_quintile5vs1 = 1.23 [95% CI, 1.03, 1.46] and OR_quintile4vs1 = 1.24 [95% CI, 1.03, 1.49]). Participants in the highest E-DII quintile also were more likely to report sleep disturbances (OR_quintile5vs1 = 1.14 [95% CI, 1.02, 1.27]).

CONCLUSIONS

Adults consuming proinflammatory diets were more likely to have short sleep duration, long sleep duration, and/or self-reported sleep disturbances. Future, especially longitudinal, studies need to examine the impact of anti-inflammatory diets in mitigating extreme sleep durations and sleep disturbances.

Maternal Sleep Quality is Associated with Personal and Parenting Weight-Related Behaviors

Mothers of young children tend to report poor-quality sleep, yet little is known about links between maternal sleep quality and weight-related behaviors and parenting practices. Thus, mothers of preschoolers completed an online cross-sectional survey assessing their sleep, physical activity, dietary behaviors, eating styles, child feeding practices, family meal behaviors, and health parameters. Comparisons by sleep quality using the Pittsburgh Sleep Quality Index item (i.e., very bad/bad, n = 87; fair, n = 255; and good/very good, n = 193) revealed mothers with poor-quality sleep had weight-related behaviors associated with higher Body Mass Index (BMI) (lower physical activity, fewer fruits/vegetables, more emotional and disinhibited eating). Poor-quality sleepers also engaged in parenting practices contrary to recommendations, such as less frequent modeling of healthy eating and physical activity, more control of child feeding, and fewer family meals. Mothers reporting poor-quality sleep tended to have lower parenting self-efficacy, poorer overall health status, more days of poor mental and physical health, greater depression, more stress, and higher BMIs. Future nutrition research should establish the directionality between sleep quality and health behaviors. Future interventions should help mothers develop strategies for improving sleep quality, such as increased physical activity and fruit and vegetable intake, and helping mothers realize how their sleep quality may affect parenting practices.

Association between the Degree of Processing of Consumed Foods and Sleep Quality in Adolescents

The aim of this study was to evaluate the association between food consumption by the degree of processing and sleep quality in adolescents from São Luís, Maranhão, Brazil. A cross-sectional study with 2499 adolescents (aged 18 to 19 years) was developed. Exposure variables included energy contributions of food groups stratified by the NOVA classification: fresh or minimally processed foods (FMPF), processed foods (PF), and ultra-processed foods (UPF), categorized into quartiles. The outcome variable was sleep quality assessed with the Pittsburgh Sleep Quality Index. Associations between these variables were estimated by Poisson regression, with robust estimation of variance. Most of the adolescents had poor sleep quality (57.1%). There were associations between FMPF in the third (57.1%-66.0% of total calories; prevalence ratio PR = 0.88; 95% CI: 0.80, 0.97) and fourth quartile (66.1%-95.8% of total calories; PR = 0.87; 95% CI: 0.78, 0.96) and lower prevalence of poor sleep quality. The fourth quartile of UPF (44.3%-81.8% of total calories; PR = 1.14; 95% CI: 1.03, 1.27) was associated with a higher prevalence of poor sleep quality. Higher intake of FMPF is a protective factor for poor sleep quality, whereas higher UPF consumption is a risk factor for poor sleep quality.