Sleep quality and Dietary Inflammatory Index among university students: a cross-sectional study

Dietary inflammatory index (DII) and sleep quality, duration, and timing: A systematic review

Sleep has strong inflammatory underpinnings and diet is one of the primary determinants of systemic inflammation. A systematic literature review was conducted to synthesize current research associating dietary inflammatory potential, as measured by the dietary inflammatory index (DII®) or the energy-adjusted DII (E-DII™) and sleep quality and duration. The National Library of Medicine (Medline), Web of Science, and PsycInfo databases were searched through March 2023. Studies must have used the DII/E-DII as the independent variable and sleep outcomes as dependent variables. Study characteristics, based on STROBE guidelines, were scored based on the presence of the recommendation. Out of the initial 14 studies identified, a total of 12 studies were included for data synthesis. In all 12 studies, more anti-inflammatory diets (i.e., low DII/E-DII scores) were associated with better sleep in at least one sleep domain (most often sleep efficiency and wake-after-sleep-onset). Among those studies with more rigorous diet and sleep measurements, such as dietary recalls and actigraphy, associations between DII/E-DII and sleep outcomes were stronger and more consistent compared to studies using primarily subjective assessments. More rigorous measurement of diet and sleep, especially those relating to sleep stage structure, should be considered in future studies with prospective designs.

Association between the Dietary Inflammatory Index and Sleep Quality among Lebanese University Students

Objective  The association between sleep quality and overall health has been extensively examined. However, few studies have investigated the relationship between sleep and the inflammatory potential of the diet. Thus, the purpose of the present study was to explore the association between the scores on the Energy-Adjusted Dietary Inflammatory Index (E-DII) and sleep quality in Lebanese university students. Materials and Methods  We conducted a cross-sectional study with students attending the Tripoli campus of Beirut Arab University. A total of 270 students aged between 17 and 25 years were randomly selected. All students filled out a multicomponent questionnaire that included an assessment of their sleep quality using the Pittsburg Sleep Quality Index, and of their physical activity level using the short version of the International Physical Activity Questionnaire. The scores on the E-DII were calculated based on a validated food frequency questionnaire. Results  Individuals in the highest (most proinflammatory) quartile of the E-DII were at an increased risk of having poor overall sleep quality compared with the lowest quartile (odds ratio [OR] = 2.86; 95% confidence interval [95%CI]: 1.27-6.44). Regarding the individual domains of sleep quality, subjects in quartiles 3 and 4 of the E-DII were at an increased risk of having poor sleep efficiency compared with those in quartile 1 (OR = 2.49; 95%CI: 1.12-5.54; and OR = 2.52, 95%CI: 1.13-5.62 respectively). However, individuals in quartile 3 were at a reduced risk of having daytime dysfunction compared with those in the lowest quartile (OR = 0.44; 95%CI: 0.23-0.83). Conclusion  The inflammatory potential of the diet seems to be related to sleep quality in our sample of Lebanese university students. Future prospective studies are required to further explore this association.

The association of dietary inflammatory index with sleep outcomes: A systematic review

Background

Sleep is a vital physiological process that plays a crucial role in various aspects of human health and well-being. Regarding the important role of diet on the sleep quality, the present study aimed to assess the association of dietary inflammatory index (DII) with the sleep outcomes and also to provide the potential mechanisms of action.

Methods

PubMed, Web of Science and Scopus databases and Google Scholar search engine were systematically searched for relevant studies related to DII and sleep outcomes using appropriate search terms until February 2024.

Results

From the initial systematic search of databases, 197 studies were retrieved. However, only 14 of them met the criteria for evaluation. Out of these, eleven studies indicated a significant correlation between higher DII scores and poor overall sleep quality and/or short/long sleep duration or its subscales. On the contrary, four studies did not find any proof of this association.

Conclusion

This systematic review indicated that following an anti-inflammatory diet could potentially lead to an improvement in the sleep outcomes. Well-designed clinical trials in the future will be necessary to provide a better understanding and quantification of this association.

The Association Between Diets With High Inflammatory Potential and Sleep Quality and Its Parameters: A Systematic Review

CONTEXT

Dietary components or its overall properties can influence an individual's sleep status.

OBJECTIVE

The aim for this study was to critically search, appraise, and synthesize research evidence on the association between dietary inflammatory index (DII) and sleep quality and its parameters.

DATA SOURCES

Original published studies on adults were obtained from the PubMed, SCOPUS, ScienceDirect, Cochrane Library, and Google Scholar databases.

DATA EXTRACTION

The search was conducted without date limitation until April 2023. Duplicated and irrelevant investigations were screened out, and the results of the remaining articles were descriptively summarized, then critically appraised and analyzed. Possible mechanistic pathways regarding diet, systemic inflammation, and sleep status were discussed.

DATA ANALYSIS

Of the 102 studies searched, 23 articles (n = 4 cohort studies, 18 cross-sectional studies, and 1 intervention study) were included in the final review. The association between DII and sleep status was investigated subjectively in 21 studies and objectively in 6 studies. The main studied sleep outcomes were sleep quality, duration, latency, efficiency, apnea, disturbances, the use of sleeping medications, daytime dysfunctions, wakefulness after sleep onset, and rapid eye movement.

CONCLUSIONS

According to most of the evidence, DII may not be related to overall sleep quality, sleep duration, latency, efficiency, and the use of sleeping medications. The evidence of positive association was greater between a high DII score (pro-inflammatory diet) with daytime dysfunctions, wakefulness after sleep onset, and sleep apnea. There is insufficient evidence to make any conclusion regarding sleep disturbances and rapid eye movement.

Faris M, G. Albalushi A, Alsaedi F, Khan SA, Khan MA. Sleep disruptions and associated risk factors among Iranians during Ramadan amid COVID-19 pandemic: A nationwide cross-sectional study

The global COVID-19 pandemic has disrupted daily routines and heightened stress levels worldwide, impacting various aspects of health, including sleep. This cross-sectional study conducted in Iran aimed to investigate the impact of Ramadan Intermittent Fasting (RIF) during the pandemic on sleep disturbances and associated risk factors in adults aged ≥ 18 years. Data was collected from Iranian participants observing RIF. A structured electronic questionnaire, translated into Persian, gathered information on sociodemographics, dietary habits, sleep parameters, physical activity, and more. The study assessed sleep quality, duration, and disturbances and conducted a thorough analysis to identify risk factors associated with sleep disruptions. The study revealed that 48% of the participants experienced sleep disturbances during RIF, with 21% reporting poor sleep quality and 46% having unusual sleep duration. Various factors were associated with an elevated risk of sleep disruptions, including body mass index, place of residence, income levels, cohabitation status, family history of obesity, hypertension, diabetes, heart disease, personal history of obesity, weight fluctuations, Shisha smoking, and unemployment. The results highlight the critical importance of health promotion strategies tailored to cultural contexts. This study advocates for enhanced health education initiatives focusing on sleep hygiene and stress management, especially during periods of significant lifestyle alterations like Ramadan amid a global pandemic. Such initiatives are vital in mitigating sleep disturbances and promoting overall well-being in populations facing unique health challenges.

The Prevalence of Depression and Anxiety and Its Association with Sleep Quality in the First-Year Medical Science Students

Methods

A total number of 471 freshmen students (NUMS) participated in the study, pinpointing that the data are collected in 2019 and 2020. In line with measuring depression, anxiety, and sleep quality, the Persian Beck Depression Inventory-II, Beck Anxiety Inventory, and Pittsburgh Sleep Quality Index were employed. The associations between depression and anxiety with sleep quality were assessed by using the multiple logistic regression model. All statistical analyses were conducted in STATA14, and the significant level was set at P < 0.05.

Results

The prevalence of depression, anxiety, and poor sleep quality in the study population was 21.4%, 31.9%, and 28%, respectively. Analytical analyses indicated that after adjusting for studied covariates, the odds of poor sleep quality in individuals with depression were 3.5 times higher compared to the counter group (P < 0.001). Moreover, the odds of poor sleep quality in individuals with anxiety were 2.1 times higher compared to the counter group (P < 0.001).

Conclusion

Noticeable proportion of freshmen students suffer from depression and anxiety; in line with such a critical issue, our study found that depression and anxiety had a statistical association with sleep quality in study population. From this respect, it seems that providing essential interventions and psychological counseling services could be constructive for the freshmen medical students.

Relation between dietary inflammatory potential and sleep features: Systematic review of observational studies

BACKGROUND: Diet and sleep represent key behavioral risk factors for major non-communicable diseases. Dietary factors may modulate systemic inflammation and potentially affect the human brain functionality, finally affecting the sleep-wake cycle. In this context, the Dietary Inflammatory Index (DII) has been studied as a tool to investigate the dietary inflammatory potential and its relationship with a variety of health conditions. OBJECTIVE: The aim of this study was to perform a systematic revision of observational studies on the inflammatory potential of the diet assessed through the DII and sleep features. METHODS: A systematic search of observational studies on DII and sleep features was conducted on Pubmed and EMBASE electronic databases. The Meta-analyses Of Observational Studies in Epidemiology (MOOSE) guidelines were used to plan the methodology. Studies identified through the search were selected according to inclusion/exclusion criteria. RESULTS: The systematic search and review led to the selection of 13 studies. Most studies including the general population reported an association between higher inflammatory potential of the diet and worse sleep quality and suboptimal sleep duration. Some studies also reported an association with daytime sleepiness and sleep apnea. However, some studies including younger individuals (i.e., college students or young employees) reported null findings. Four studies conducted in individuals with a variety of health conditions also showed some relation between DII and sleep features, although results were not fully consistent. CONCLUSIONS: Data published so far suggests an association between DII and sleep features. However, lack of randomized clinical trials and better designed observational studies, imply that further research on this matter is warranted to understand whether a causal relation could explain current findings.

Pro-Inflammatory Diet as a Risk Factor for Stomach Cancer: Findings from a Multicenter Study in Central and Western China

Purpose

We conducted a multicenter cross-sectional study in central and western China to explore the association between inflammatory diet and stomach cancer odds.

Patients and Methods

Participants from five hospitals in the central and western regions were collected. All participants completed the questionnaire we provided before the gastroscopy examination, which includes inquiries about risk factors for stomach cancer and food frequency. All participants underwent gastroscopy, and a mucosal biopsy was confirmed pathologically. Pathological findings were classified as chronic gastritis group, precancerous lesions group and stomach cancer group. Dietary Inflammatory Index (DII) scores were calculated based on the frequency of food occurrences in the questionnaire, and finally SPSS was used to calculate the correlation between variables.

Results

A total of 1162 patients were included in this study, including 668 cases of chronic gastritis, 411 cases of precancerous lesions, and 83 cases of cancer. A single factor analysis was conducted to examine the risk factors of stomach cancer, revealing a significant association between a pro-inflammatory diet and the stomach cancer odds (p value < 0.05). The results of binary classification analysis further confirmed that a pro-inflammatory diet is a risk factor for stomach cancer 【odds ratio (OR) =7.400)】. Moreover, correlation analysis demonstrated a positive correlation between the severity of gastric mucosal diseases and an inflammatory diet (including anti-inflammatory and pro-inflammatory diets) (rs=0.274, p-value < 0.001).

Conclusion

Pro-Inflammatory diet is a risk factor for stomach cancer, and may accelerate the progression of stomach mucosal disease.

The association between energy-adjusted dietary inflammatory index and physical activity with sleep quality: a cross-sectional study

BACKGROUND

The study aimed to assess the independent and interactive association of energy-adjusted dietary inflammatory index (E-DII) and physical activity (PA) with sleep quality.

METHOD

A cross-sectional study was conducted on the 2466 participants (60% women). A 116-item food frequency questionnaire (FFQ) was applied to calculate E-DII, the International Physical Activity Questionnaire (IPAQ) long form for PA, and the Pittsburgh sleep quality index (PSQI) to assess sleep quality were collected via interview. Multivariate logistic regression was applied to assess independent and interactive associations of E-DII and PA with sleep quality.

RESULT

No significant association was observed between E-DII and sleep quality (OR: 0.96, 95% CI: 0.92_1.01). Also, there was no significant association between the levels of PA and sleep quality. Women had 70% increased odds for poor sleep quality (OR: 1.7, 95% CI: 1.39_2.09) compared with men. No interactive association was observed between E-DII and PA levels with sleep quality.

CONCLUSION

No significant association was observed between E-DII and PA levels with sleep quality. The study indicates a gender difference in sleep quality. Future prospective studies are required to confirm these findings.

Dietary inflammatory index and neuropsychiatric disorders

Neuropsychiatric disorders (NPDs) are considered a potential threat to mental health. Inflammation predominantly plays a role in the pathophysiology of NPDs. Dietary patterns are widely postulated to be involved in the physiological response to inflammation. This review aims to discuss the literature on how dietary inflammatory index (DII) is related to inflammation and, consequently, NPDs. After comprehensive scrutiny in different databases, the articles that investigated the relation of DII score and various NPDs and psychological circumstances were included. The association between dietary patterns and mental disorders comprising depression, anxiety, and stress proved the role of a proinflammatory diet in these conditions' exacerbation. Aging is another condition closely associated with DII. The impact of proinflammatory and anti-inflammatory diet on sleep quality indicated related disorders like sleep latency and day dysfunctions among the different populations are in relation with the high DII score. The potential effects of genetic backgrounds, dietary patterns, and the gut microbiome on DII are discussed as well. To plan preventive or therapeutic interventions considering the DII, these factors, especially genetic variations, should be considered as there is a growing body of literature indicating the role of personalized medicine in different NPDs. To the best of our knowledge, there is a limited number of RCTs on this subject, so future research should evaluate the causality via RCTs and look for therapeutic interventions with an eye on personalized medicine using information about DII in NPDs.

Construct Validation of the Dietary Inflammatory Index (DII) among Young College-Aged Women

The Dietary Inflammatory Index (DII) is designed to assess the inflammatory potential of the diet. While previous research has utilized DII among college-aged women, no study to date has validated it in this population. We conducted a construct validation of DII among 393 healthy women aged 18-31 years against a robust panel of 14 inflammatory biomarkers, including CRP, IL-1β, IL-4, IL-6, IL-10, and TNF-α, which were used in the development of DII. Three linear regression models were constructed: (1) an age-adjusted model, (2) the most parsimonious model based on likelihood ratio tests, and (3) a fully adjusted model for age, race, body mass index, waist circumference, physical activity, smoking status, and nonsteroidal anti-inflammatory drug use. DII was derived from the Harvard food frequency questionnaire and categorized into quartiles. Consistent with our hypothesis, DII was negatively and significantly associated with back-transformed IL-10 levels, confirming that a more pro-inflammatory diet was associated with lower levels of an anti-inflammatory cytokine (Model 3: Q4 vs. Q1 β = 0.62; 95% CI: 0.42, 0.93; p-trend = 0.04). While validated in other populations, DII may not be a suitable tool for assessing the inflammatory potential of the diet among college-aged women.

Ramadan Fasting and Short-Term Maximal Physical Performance: Searching for Optimal Timing of the Last Meal "Suhoor" in Female Pre-University Handball Players

Aiming to identify the ideal suhoor timing for maintaining optimal physical performance and health indicators during Ramadan intermittent fasting, the present study compares the effects of early vs. late Suhoor on short-term high-intensity physical exercise while controlling the body mass index (BMI) oral temperature (OT), dietary intake, and sleep patterns. In a randomized design, 19 female pre-university handball players (age: 16.8 ± 0.4 y; height: 1.70 ± 0.9 m; and body mass: 61.5 ± 6.9 kg) underwent two test sessions (at 08:00 a.m. and 05:00 p.m.) at four different conditions: ten days prior to Ramadan (R - 10), the final ten days of Ramadan (R) including both Early Suhoor R(ES) and Late Suhoor R(LS) conditions, and the ten days immediately following Ramadan (R + 10). A recovery period of at least 48 h has been set between successive test sessions at each period. Outcome measures included the Countermovement Jumps Test (CMJ), Modified Agility t-Test (MATT), Repeated Sprint Ability (RSA), and Rating of Perceived Exertion (RPE). The Pittsburgh Sleep Quality Index (PSQI), OT, BMI, and daily diary intake were assessed across the three periods. The total scores of PSQI decreased significantly during R and R + 10 compared to R - 10. When performed in the afternoon, CMJ, MATT, and RSA performance decreased significantly at R(ES) and R(LS) conditions compared to R - 10. However, these performances decreased only after R(ES) when performed in the morning. Furthermore, performances were lower during R(ES) compared to R(LS) in the afternoon for all tests and the morning for MATT and RSA tests. These findings support prior research showing a deterioration of physical performance during Ramadan fasting and indicate a more pronounced impact following early Suhoor condition. Therefore, consuming a late suhoor, closer to pre-dawn time, could be suggested as an effective strategy to minimize physical performance decline during short-term high-intensity exercise.

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.

Gut microbiota: Candidates for a novel strategy for ameliorating sleep disorders

The aim of this review was to evaluate the feasibility of treating sleep disorders using novel gut microbiota intervention strategies. Multiple factors can cause sleep disorders, including an imbalance in the gut microbiota. Studies of the microbiome-gut-brain axis have revealed bidirectional communication between the central nervous system and gut microbes, providing a more comprehensive understanding of mood and behavioral regulatory patterns. Changes in the gut microbiota and its metabolites can stimulate the endocrine, nervous, and immune systems, which regulate the release of neurotransmitters and alter the activity of the central nervous system, ultimately leading to sleep disorders. Here, we review the main factors affecting sleep, discuss possible pathways and molecular mechanisms of the interaction between sleep and the gut microbiota, and compare common gut microbiota intervention strategies aimed at improving sleep physiology.

Effect of the dietary inflammatory potential on the trajectory of body adiposity in a Brazilian cohort of university students

OBJECTIVES

University students are vulnerable to unhealthy eating habits that characterize a proinflammatory diet. This study aimed to estimate the dietary inflammatory index (DII) and its association with the trajectory of body adiposity markers in university students.

METHODS

The study analyzed data from 685 students entering a Brazilian public university in 2016 and 2017 and followed until 2018. DII was estimated from 39 dietary parameters obtained by 24-h dietary recall. Body adiposity was assessed by anthropometric markers and the percentage of body fat. Linear mixed-effects models were used to estimate the trajectory of adiposity markers according to DII tertiles.

RESULTS

After adjustment for confounding variables, at baseline, DII showed a positive association with increased percentage of body fat among men (β = 0.52; 95% CI: 0.01; 1.03) and waist-to-height ratio (WHtR; β = 0.15; 95% CI: 0.12; 0.18) and among women with all body adiposity markers: BMI (β = 0.68; 95% CI: 0.30; 1.05), percentage of body fat (β = 1.43; 95% CI: 0.74; 2.11), WC (β = 1.15; 95% CI: 0.41; 1.89) and WHtR (β = 0.13; 95% CI:0,10; 0.16). The rate of change of the outcome variables over time was not associated with DII at baseline.

CONCLUSIONS

The diet of university students in this Brazilian cohort study was characterized as proinflammatory and it was associated with body adiposity markers.

Examination of sleep in relation to dietary and lifestyle behaviors during Ramadan: A multi-national study using structural equation modeling among 24,500 adults amid COVID-19

Background

Of around 2 billion Muslims worldwide, approximately 1.5 billion observe Ramadan fasting (RF) month. Those that observe RF have diverse cultural, ethnic, social, and economic backgrounds and are distributed over a wide geographical area. Sleep is known to be significantly altered during the month of Ramadan, which has a profound impact on human health. Moreover, sleep is closely connected to dietary and lifestyle behaviors.

Methods

This cross-sectional study collected data using a structured, self-administered electronic questionnaire that was translated into 13 languages and disseminated to Muslim populations across 27 countries. The questionnaire assessed dietary and lifestyle factors as independent variables, and three sleep parameters (quality, duration, and disturbance) as dependent variables. We performed structural equation modeling (SEM) to examine how dietary and lifestyle factors affected these sleep parameters.

Results

In total, 24,541 adults were enrolled in this study. SEM analysis revealed that during RF, optimum sleep duration (7-9 h) was significantly associated with sufficient physical activity (PA) and consuming plant-based proteins. In addition, smoking was significantly associated with greater sleep disturbance and lower sleep quality. Participants that consumed vegetables, fruits, dates, and plant-based proteins reported better sleep quality. Infrequent consumption of delivered food and infrequent screen time were also associated with better sleep quality. Conflicting results were found regarding the impact of dining at home versus dining out on the three sleep parameters.

Conclusion

Increasing the intake of fruits, vegetables, and plant-based proteins are important factors that could help improve healthy sleep for those observing RF. In addition, regular PA and avoiding smoking may contribute to improving sleep during RF.

Associations between the Dietary Inflammatory Index and Sleep Metrics in the Energy Balance Study (EBS)

(1) Background: Sleep, a physiological necessity, has strong inflammatory underpinnings. Diet is a strong moderator of systemic inflammation. This study explored the associations between the Dietary Inflammatory Index (DII®) and sleep duration, timing, and quality from the Energy Balance Study (EBS). (2) Methods: The EBS (n = 427) prospectively explored energy intake, expenditure, and body composition. Sleep was measured using BodyMedia’s SenseWear® armband. DII scores were calculated from three unannounced dietary recalls (baseline, 1-, 2-, and 3-years). The DII was analyzed continuously and categorically (very anti-, moderately anti-, neutral, and pro-inflammatory). Linear mixed-effects models estimated the DII score impact on sleep parameters. (3) Results: Compared with the very anti-inflammatory category, the pro-inflammatory category was more likely to be female (58% vs. 39%, p = 0.02) and African American (27% vs. 3%, p < 0.01). For every one-unit increase in the change in DII score (i.e., diets became more pro-inflammatory), wake-after-sleep-onset (WASO) increased (βChange = 1.00, p = 0.01), sleep efficiency decreased (βChange = −0.16, p < 0.05), and bedtime (βChange = 1.86, p = 0.04) and waketime became later (βChange = 1.90, p < 0.05). Associations between bedtime and the DII were stronger among African Americans (βChange = 6.05, p < 0.01) than European Americans (βChange = 0.52, p = 0.64). (4) Conclusions: Future studies should address worsening sleep quality from inflammatory diets, leading to negative health outcomes, and explore potential demographic differences.

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.

Higher Dietary Inflammatory Index Scores Are Associated With Stress and Anxiety in Dormitory-Residing Female University Students in the United Arab Emirates

Dormitory-residing university students are at-risk of mental health problems related to unhealthy diets. The purpose of this study was to assess the association between dietary inflammatory potential and mental health of dormitory-residing female university students. This cross-sectional study was comprised of 260 undergraduate females residing in dormitories of the largest university in United Arab Emirates during Spring 2019. The Energy-adjusted Dietary Inflammatory Index (E-DIITM) scores calculated from 37 food parameters were derived from two 24-h dietary recalls. The logistic regression analysis was used to estimate odds ratios (ORs) and 95% CIs for the E-DII score in relation to depression, anxiety, and stress. The E-DII scores (mean = 2.98 ± 1.17) were categorized into: tertile 1 (−1.96–2.62), tertile 2 (2.63–3.52), and tertile 3 (3.53–5.60), representing less to more proinflammatory diets. Students in the E-DII tertile 3 had significantly higher depression, anxiety, and stress scores. The logistic regression analysis showed that each point increase in the E-DII score was associated with symptoms of stress (OR = 1.41; 95% CI: 1.12–1.77; p = 0.003) and anxiety (OR = 1.35; 95% CI: 1.07–1.69; p = 0.01). Relative to students in the E-DII tertile 1, those students in the E-DII tertile 3 were more likely to be at higher risk of stress and anxiety ORE−DIItertile3vs1 = 2.89 (1.44–5.79) and 2.88 (1.49–5.56), respectively. Overall, stress and anxiety were associated with proinflammatory diets in dormitory-residing female university students, suggesting the need for targeted interventions to increase the anti-inflammatory capacity of diet and improve mental wellbeing in students on university campuses.

Longitudinal and cross-sectional associations between the dietary inflammatory index and objectively and subjectively measured sleep among police officers

Police officers experience exposures associated with increased inflammation, such as the stress associated with shiftwork and poor-quality diet, both of which have been shown to affect sleep duration and quality. This study examined the longitudinal and cross-sectional effects of the Energy-density Dietary Inflammatory Index (E-DII™) on objectively and subjectively measured sleep among police officers. Data were derived from the Buffalo Cardio-Metabolic Occupational Police Stress Cohort (n = 464 at baseline), with longitudinal data collected from 2004 to 2019. A food frequency questionnaire obtained estimated dietary intake from which E-DII scores were calculated. Dependent variables were objectively (Micro Motion Logger Sleep Watch™) and subjectively (Pittsburgh Sleep Quality Index) measured sleep quality and quantity. The analyses included a series of linear mixed-effects models used to examine cross-sectional and longitudinal associations between the E-DII and sleep quantity and quality. Cross-sectionally, more pro-inflammatory diets were associated with higher wake-after-sleep-onset but improved subjective sleep quality. In models accounting for both longitudinal and cross-sectional effects, for every 1-unit increase in the E-DII scores over time (representing a pro-inflammatory change), wake-after-sleep-onset increased by nearly 1.4 min (p = 0.07). This result was driven by officers who primarily worked day shifts (β = 3.33, p = 0.01). Conversely, for every 1-unit increase in E-DII score, the Pittsburgh Sleep Quality Index global score improved. More pro-inflammatory diets were associated with increased wake-after-sleep-onset, an objective measure of sleep quality. Intervention studies to reduce dietary inflammatory potential may provide greater magnitude of effect for changes in sleep quality.

Association of carbonated soft drink and fast food intake with stress-related sleep disturbance among adolescents: A global perspective from 64 countries

BACKGROUND

Poor quality sleep adversely impacts on adolescent wellbeing. More multinational research is needed to understand modifiable risk factors, such as dietary behaviours. This study aimed to examine the association of carbonated soft drink and fast food intake with stress-related sleep disturbance among adolescents across 64 countries.

METHODS

We analysed the Global School-based Student Health Survey data from 175,261 adolescents (mean age 13.8 [0.98]; 48.5% females). Adolescents reported frequency of stress-related sleep disturbance and consumption of carbonated soft drinks and fast foods. Country-level estimates were obtained by using multivariable logistic regression and meta-analysis to obtain pooled estimates.

FINDINGS

Overall, 7.5% of adolescents reported sleep disturbance during the past 12 months (males: 6.6%; females: 8.4%). Meta-analysis showed that adolescents having carbonated soft drinks ≥3 times/day had over 50% higher odds of reporting sleep disturbance than <once/day (OR=1.55, 95% CI 1.42-1.70 for males; 1.51, 1.37-1.68 for females). Adolescent males who had fast foods ≥4 days/week had 55% higher odds of reporting sleep disturbance than ≤1 day/week (1.55, 1.39-1.73), while the odds was 50% higher in females (1.50, 1.32-1.70). Carbonated soft drinks ≥3 times/day and fast foods ≥ 4 days/week were significantly associated with sleep disturbance in all but low-income countries for both genders; while the associations were significant in males and mixed in females across WHO regions.

INTERPRETATION

Our findings suggest strong positive associations between carbonated soft drink and fast food intake with stress-related sleep disturbance. Prospective studies are needed to understand the directionality of the relationship.