Eating meals irregularly: a novel environmental risk factor for the metabolic syndrome

Distinct biophysiological effects of Ramadan fasting and traditional intermittent fasting on markers of body fat storage. A real-life study

BACKGROUND

Ramadan Intermittent fasting (RIF) exerts beneficial metabolic effects and improves gastrointestinal motility. However, a comparison between RIF and the traditional 16-hours intermittent fasting (16IF), a strategy for weight loss, is lacking.

METHODS

A total of 34 subjects (median age 32.5 years, range 18-63 years; median BMI 24.5 Kg m-1², range 18.6-37.6 Kg m-1²) were assigned to RIF (N = 18) or 16IF (N = 16) for 30 days. We measured variations in anthropometric measures (BMI, waist, and abdominal circumference), serum insulin, glucose, cortisol, non-esterified fatty acid (NEFA), body fat composition (bioelectrical impedance analysis), and the ultrasonographic measurements of liver steatosis (Hepatorenal index, HRI) and thickness of subcutaneous (SAT) and visceral (VAT) fats.

RESULTS

At baseline, BMI, rates of liver steatosis and distribution of normal weight, overweight, and obese subjects were comparable between the two groups. Body weight significantly decreased at the end of fasting in both RIF (-4.2 % vs baseline, P = 0.002) and 16IF (-2.1 % vs baseline, P = 0.002). Waist and abdominal circumferences significantly decreased only in RIF as well as the amount of body fat. In subjects with liver steatosis, SAT and VAT significantly decreased following RIF, but not 16h-IF, as well as the ultrasonographic HRI.

CONCLUSION

Both 16IF and RIF are able, during 1-month, to reduce body weight. However, RIF but not 16IF also generates marked beneficial effects in terms of reduced subcutaneous fat and liver steatosis. Further studies urge to verify the effects of different models of IF in weight-cycling and long-term management of obesity and related dysmetabolic conditions, such as ectopic fat over-storage.

The association between diet quality and chrononutritional patterns in young adults

PURPOSE

Young adults eat erratically and later in the day which may impact weight and cardiometabolic health. This cross-sectional study examined relationships between chrononutritional patterns and diet quality in two young adult populations: a university and community sample.

METHODS

Three days of dietary data were collected including food images captured using wearable cameras. Chrononutritional variables were extracted: time of first and last eating occasions, caloric midpoint (time at which 50% of daily energy was consumed), number of eating occasions per day, eating window, day-to-day variability of the above metrics, and evening eating (≥20:00h). The Healthy Eating Index for Australian Adults scored diet quality. Statistical analyses controlled for gender, body mass index, and socio-economic status.

RESULTS

No significant associations between chrononutritional patterns and diet quality were found for all participants (n = 95). However, differences in diet quality were found between university (n = 54) and community (n = 41) samples with average diet quality scores of 59.1 (SD 9.7) and 47.3 (SD 14.4), respectively. Of those who extended eating ≥20:00 h, university participants had better diet quality (62.9±SE 2.5 vs. 44.3±SE 2.3, p < 0.001) and discretionary scores (7.9±SE 0.9 vs. 1.6±SE 0.6, p < 0.001) than community participants. University participants consumed predominately healthful dinners and fruit ≥20:00h whereas community participants consumed predominately discretionary foods.

CONCLUSION

For the general young adult population, meal timing needs to be considered. Food choices made by this cohort may be poorer during evenings when the desire for energy-dense nutrient-poor foods is stronger. However, meal timing may be less relevant for young adults who already engage in healthy dietary patterns.

Unfavorable Mealtime, Meal Skipping, and Shiftwork Are Associated with Circadian Syndrome in Adults Participating in NHANES 2005-2016

The concept of Circadian Syndrome (CircS) aims to emphasize the circadian disruptions underlying cardiometabolic conditions. Meal timing and shiftwork may disrupt circadian rhythms, increasing cardiometabolic risk. This study aimed to assess the associations of meal timing, meal skipping, and shiftwork with CircS in US adults and explore effect modifications by sociodemographic and lifestyle factors. CircS was defined using Metabolic Syndrome components in addition to short sleep and depression symptoms. Data from 10,486 participants of the National Health and Nutrition Examination Survey 2005-2016 were analyzed cross-sectionally. Mealtime was assessed by calculating the midpoint of intake between breakfast and dinner and dichotomizing it into favorable mealtime (between 12:30 and 13:15) and unfavorable mealtime using a data-driven approach. Meal skippers were categorized separately. Participants working evening, night, or rotating shifts were classified as shift workers. In the multivariable logistic regression analysis, an unfavorable mealtime, meal skipping, and shiftwork were associated with a higher likelihood of CircS (OR = 1.24; 95%CI 1.07-1.44, OR = 1.39; 95%CI 1.16-1.67, and OR = 1.37; 95%CI 1.01-1.87, respectively). Subgroup analyses revealed no significant interactions between meal timing, meal skipping, or shiftwork and socioeconomic status or lifestyle regarding CircS. These findings highlight the importance of aligning mealtimes with circadian rhythms for improved circadian health.

Diet and Meal Pattern Determinants of Glucose Levels and Variability in Adults with and without Prediabetes or Early-Onset Type 2 Diabetes: A Pilot Study

This observational pilot study examined the association between diet, meal pattern and glucose over a 2-week period under free-living conditions in 26 adults with dysglycemia (D-GLYC) and 14 with normoglycemia (N-GLYC). We hypothesized that a prolonged eating window and late eating occasions (EOs), along with a higher dietary carbohydrate intake, would result in higher glucose levels and glucose variability (GV). General linear models were run with meal timing with time-stamped photographs in real time, and diet composition by dietary recalls, and their variability (SD), as predictors and glucose variables (mean glucose, mean amplitude of glucose excursions [MAGE], largest amplitude of glucose excursions [LAGE] and GV) as dependent variables. After adjusting for calories and nutrients, a later eating midpoint predicted a lower GV (β = -2.3, SE = 1.0, p = 0.03) in D-GLYC, while a later last EO predicted a higher GV (β = 1.5, SE = 0.6, p = 0.04) in N-GLYC. A higher carbohydrate intake predicted a higher MAGE (β = 0.9, SE = 0.4, p = 0.02) and GV (β = 0.4, SE = 0.2, p = 0.04) in N-GLYC, but not D-GLYC. In summary, our data suggest that meal patterns interact with dietary composition and should be evaluated as potential modifiable determinants of glucose in adults with and without dysglycemia. Future research should evaluate causality with controlled diets.

Longitudinal associations of circadian eating patterns with sleep quality, fatigue and inflammation in colorectal cancer survivors up to 24 months post-treatment

Fatigue and insomnia, potentially induced by inflammation, are distressing symptoms experienced by colorectal cancer (CRC) survivors. Emerging evidence suggests that besides the nutritional quality and quantity, also the timing, frequency and regularity of dietary intake (chrono-nutrition) could be important for alleviating these symptoms. We investigated longitudinal associations of circadian eating patterns with sleep quality, fatigue and inflammation in CRC survivors. In a prospective cohort of 459 stage I-III CRC survivors, four repeated measurements were performed between 6 weeks and 24 months post-treatment. Chrono-nutrition variables included meal energy contribution, frequency (a maximum of six meals could be reported each day), irregularity and time window (TW) of energetic intake, operationalised based on 7-d dietary records. Outcomes included sleep quality, fatigue and plasma concentrations of inflammatory markers. Longitudinal associations of chrono-nutrition variables with outcomes from 6 weeks until 24 months post-treatment were analysed by confounder-adjusted linear mixed models, including hybrid models to disentangle intra-individual changes from inter-individual differences over time. An hour longer TW of energetic intake between individuals was associated with less fatigue (β: -6·1; 95 % CI (-8·8, -3·3)) and insomnia (β: -4·8; 95 % CI (-7·4, -2·1)). A higher meal frequency of on average 0·6 meals/d between individuals was associated with less fatigue (β: -3·7; 95 % CI (-6·6, -0·8)). An hour increase in TW of energetic intake within individuals was associated with less insomnia (β: -3·0; 95 % CI (-5·2, -0·8)) and inflammation (β: -0·1; 95 % CI (-0·1, 0·0)). Our results suggest that longer TWs of energetic intake and higher meal frequencies may be associated with less fatigue, insomnia and inflammation among CRC survivors. Future studies with larger contrasts in chrono-nutrition variables are needed to confirm these findings.

Relationship between circadian eating behavior (daily eating frequency and nighttime fasting duration) and cardiovascular mortality

BACKGROUND

Knowledge regarding the health impacts of daily eating frequency (DEF) and nighttime fasting duration (NFD) on mortality is very limited.

OBJECTIVE

This study aimed to examine whether DEF and NFD are associated with CVD and all-cause mortality.

METHODS

This was a prospective cohort study of a nationally representative sample from the United States, including 30,464 adults who participated in the National Health and Nutrition Examination Survey 2003-2014. Using 24-h dietary recall, DEF was assessed by the number of eating episodes, and NFD was calculated by the first and last eating time across a day. Death information was obtained from the National Death Index up to 2019. Weighted Cox proportional hazards regression models were used to assess survival relationships of DEF and NFD with mortality.

RESULTS

During 307,686 person-years of follow-up, 4560 deaths occurred, including 1824 CVD cases. After adjustment for confounders, compared to DEF at 4-6 times, participants whose DEF was less than 3 times had greater CVD [hazard-ratio (HR) = 1.33, 95% confidence-interval (CI): 1.06-1.67] and all-cause (HR = 1.16, 95% CI: 1.01-1.33) mortality risks. Furthermore, compared to NFD of 10 to 11 h, participants whose NFD was shorter than 10 h had HRs of 1.30 (95% CI: 1.08-1.55) for CVD mortality and 1.23 (95% CI: 1.08-1.39) for all-cause mortality. NFD longer than 14 h was also related to CVD mortality (HR = 1.37, 95% CI: 1.12-1.67) and all-cause mortality (HR = 1.36, 95% CI: 1.19-1.54). Similar results for the association of NFD and DEF with heart-specific and stroke-specific mortality were observed.

CONCLUSION

This study found that DEF less than 3 times and NFD shorter than 10 h or longer than 14 h were independently associated with greater cardiovascular and all-cause mortality.

A systematic review of associations between day-to-day variability in meal pattern and body weight, components of the metabolic syndrome and cognitive function

BACKGROUND

Meal pattern is a potential health determinant. Previously, mean values for properties of meal pattern, such as daily meal frequency, have been considered. Means, however, obscure variability between-day (irregular or chaotic eating). This systematic review aimed to identify and critique published methods used to characterise between-day variability in meal pattern, and to explore relationships between this and obesity, as well as associated health outcomes.

METHODS

Using relevant databases, a systematic search was undertaken for studies with adults and children in which between-day variability in meal pattern was measured, and related to body weight, metabolic syndrome components and cognitive function.

RESULTS

In 34 papers identified (28 observational and six intervention studies), between-day variability in meal pattern was characterised by a variety of methods. These ranged from single questions about intake regularity to more complex methods quantifying the degree of variability. Assumptions were made, such as there being three main meals, resulting in dissociation from the "clock time" of eating. In 24 of the papers, between-day variability in meal pattern was associated with negative weight and health outcomes including higher weight, reduced thermogenic response to meals and poorer academic achievement.

CONCLUSIONS

Between-day variability in meal pattern is a promising research area that might inform low-cost public health interventions. However, current methods of characterising between-day variability tend to make assumptions and be inconsistent in the meal pattern properties considered. Well controlled dietary intervention studies are required to confirm causation.

Effect of skipping breakfast on cardiovascular risk factors: a grade-assessed systematic review and meta-analysis of randomized controlled trials and prospective cohort studies

Skipping breakfast is one of the most prevalent irregular eating habits. Several pieces of evidence have reported the association between breakfast omission and a higher risk of cardiovascular diseases. Numerous publications have focused on the impact of skipping breakfast on various cardiovascular risk factors. Therefore, the current systematic review and meta-analysis aimed to assess this impact, especially with regard to anthropometric measurements, serum lipid profiles, blood pressure, and glycemic control indicators. A comprehensive search was performed in PubMed, Web of Science, Embase, Scopus, and the Cochrane Central Register of Controlled Trials up to 1 April 2023. A total of 11 eligible trials were identified to evaluate the combined effects of skipping breakfast. Final integrated results demonstrated that breakfast omission significantly decreased the body weight (mean difference = -0.66, 95% CI: -1.09 to -0.24, p = 0.002, I2 = 0.0) and increased the level of serum low-density lipoprotein cholesterol (LDL-C) (mean difference = 9.89, 95% CI: 5.14 to 14.63, p = 0.000, I2 = 17.3). Subgroup analysis also revealed potential factors that may affect the outcomes, for example, the physiological condition of participants, duration, gender, and type of breakfast. In conclusion, skipping breakfast may reduce body weight while increasing the level of serum LDL-C at the same time. In view of the limited trials, further studies are needed to expound the role of breakfast omission in cardiovascular diseases.

Racial Differences in Psychiatric Symptoms, Maladaptive Eating, and Lifestyle Behaviors After Bariatric Surgery

There are several psychological and behavioral factors associated with poorer outcomes following bariatric surgery, yet it is unknown whether and how these factors may differ by race. In this cross-sectional study, individuals who underwent bariatric surgery from 2018 to 2021 and up to 4 years post-surgery were invited to complete an online survey. Psychiatric symptoms, maladaptive eating patterns, self-monitoring behaviors, and exercise frequency were examined. Participants (N = 733) were 87% women, 63% White, with a mean age of 44 years. Analyses of covariance demonstrated that White individuals endorsed greater anxiety symptoms (p =.01) and emotional eating due to depression (p = .01), whereas Black individuals endorsed greater depression severity (p = .02). Logistic regression analyses demonstrated that White individuals were more likely to experience loss of control eating (OR= 1.7, p = .002), grazing (OR= 2.53, p <.001), and regular self-weighing (OR= 1.41, p <.001) than Black individuals, and were less likely to skip meals (OR= .61, p = .04), or partake in nighttime eating (OR= .40, p <.001). There were no racial differences in binge eating, emotional eating due to anxiety or frustration, use of a food diary, or exercise. Thus, depressive symptoms, skipping meals, and nighttime eating may be important, modifiable intervention targets to optimize the benefits of bariatric surgery and promote equitable outcomes.

Timing of energy intake and the therapeutic potential of intermittent fasting and time-restricted eating in NAFLD

Non-alcoholic fatty liver disease (NAFLD) represents a major public health concern and is associated with a substantial global burden of liver-related and cardiovascular-related morbidity and mortality. High total energy intake coupled with unhealthy consumption of ultra-processed foods and saturated fats have long been regarded as major dietary drivers of NAFLD. However, there is an accumulating body of evidence demonstrating that the timing of energy intake across a the day is also an important determinant of individual risk for NAFLD and associated metabolic conditions. This review summarises the available observational and epidemiological data describing associations between eating patterns and metabolic disease, including the negative effects of irregular meal patterns, skipping breakfast and night-time eating on liver health. We suggest that that these harmful behaviours deserve greater consideration in the risk stratification and management of patients with NAFLD particularly in a 24-hour society with continuous availability of food and with up to 20% of the population now engaged in shiftwork with mistimed eating patterns. We also draw on studies reporting the liver-specific impact of Ramadan, which represents a unique real-world opportunity to explore the physiological impact of fasting. By highlighting data from preclinical and pilot human studies, we present a further biological rationale for manipulating timing of energy intake to improve metabolic health and discuss how this may be mediated through restoration of natural circadian rhythms. Lastly, we comprehensively review the landscape of human trials of intermittent fasting and time-restricted eating in metabolic disease and offer a look to the future about how these dietary strategies may benefit patients with NAFLD and non-alcoholic steatohepatitis.

Association of main meal frequency and skipping with metabolic syndrome in Korean adults: a cross-sectional study

BACKGROUND

Reduced meal frequency can increase the risk of metabolic syndrome (MetS). However, limited studies have examined the association between meal frequency and skipping meals with MetS. This study aims to analyze the association between main meal frequency and meal skipping with MetS in Korean adults aged ≥ 19 years.

METHODS

In this study, we included data from 22,699 Korean adult participants from the 2016-2020 Korea National Health and Nutrition Examination Survey (KNHANES). The 24-h dietary recall method was used to classify the participants into three groups based on main meal frequency (one, two, or three meals per day) and seven groups based on the type of main meal they skipped. Multivariable logistic regression analysis was conducted to determine the association between main meal frequency and the types of main meals skipped with the odds of MetS and its associated components. Appropriate estimates were accounted for using sampling weights, stratification, and clustering.

RESULTS

The prevalence of MetS in the study population was 33.8%. The average age of the participants was 47.2 years with 42.6% being men, and 57.4% being women. Men who consumed two meals per day had higher odds of MetS than those who consumed three meals per day (odds ratio [OR] 1.16, 95% confidence interval [CI] 1.01-1.33). Women who consumed two meals per day, and skipped breakfast had increased odds of having elevated fasting blood glucose levels (OR 1.18, 95% CI 1.02-1.35), and elevated triglycerides (OR 1.19, 95% CI 1.02-1.39). However, women who skipped dinner had reduced odds of having elevated fasting blood glucose levels (OR 0.74, 95% CI 0.58-0.94).

CONCLUSIONS

Our findings suggest that meal frequency and the type of main meal skipped may be associated with MetS and emphasize the importance of consuming breakfast to prevent MetS.

The Association between the Atherogenic Index of Plasma and Cardiometabolic Risk Factors: A Review

Background: Metabolic syndrome (MetS) is a condition caused by a combination of cardiometabolic risk factors (CMR). MetS leads to type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD), both of which place a burden on not only the patients but also the healthcare system. Diagnostic criteria for MetS vary, and there is no universal tool to detect it. Recently, many studies have found positive associations between the atherogenic index of plasma (AIP) and some CMR factors. Therefore, a comprehensive review was needed to recapitulate these studies and qualitatively estimate the likelihood of AIP being associated with CMR. We aimed to review and summarise observational data on AIP and CMR factors and verify their association. Materials and Methods: A review of observational studies was conducted by searching “atherogenic index of plasma” in PubMed, One Search, and the Cochrane library. A total of 2068 articles were screened, and 32 were included after excluding paediatric, non-human and interventional studies, and those carried out on cohorts with conditions unrelated to MetS or on lipid-lowering medication. The Newcastle-Ottawa scale was used to assess their quality. Results: Most studies that reported high waist circumference (WC), triglycerides (TG), insulin resistance (IR) and low high-density lipoprotein cholesterol (HDL-C) concentration, also reported high AIP. Few studies investigated blood pressure (BP) and some discrepancies existed between their results. Conclusion: AIP may be associated with WC, TG, IR, and HDL-C. It is unclear if AIP is associated with BP. The current study’s results should be used to inform futureward a meta-analysis to be seen quantitatively. It is also recommended that more cohort studies stratified by gender and ethnicity be performed to ascertain if AIP can predict MetS before it manifests.

Impact of dietary carbohydrate restriction on the pathobiology of Hepatocellular Carcinoma: The gut-liver axis and beyond

Despite decades of fiercely competitive research and colossal financial investments, the majority of patients with advanced solid cancers cannot be treated with curative intent. To improve this situation, conceptually novel treatment approaches are urgently needed. Cancer is increasingly appreciated as a systemic disease and numerous organismal factors are functionally linked to neoplastic growth, e.g. systemic metabolic dysregulation, chronic inflammation, intestinal dysbiosis and disrupted circadian rhythms. It is tempting to hypothesize that interventions targeting these processes could be of significant account for cancer patients. One important driver of tumor-supporting systemic derangements is inordinate consumption of simple and highly processed carbohydrates. This dietary pattern is causally linked to hyperinsulinemia, insulin resistance, chronic inflammation and intestinal dysbiosis, begging the pertinent question whether the adoption of dietary carbohydrate restriction can be beneficial for patients with cancer. This review summarizes the published data on the role of dietary carbohydrate restriction in the pathogenesis of Hepatocellular Carcinoma (HCC), the most frequent type of primary liver cancer. In addition to outlining the functional interplay between diet, the intestinal microbiome and immunity, the review underscores the importance of bile acids as interconnectors between the intestinal microbiota and immune cells.

Association between meal frequency with anthropometric measures and blood pressure in Iranian children and adolescents

BACKGROUND

This study aimed to assess the association of meal frequency with anthropometric measures and blood pressure in Iranian children and adolescents.

METHODS

In this national survey, 14,880 students with 6-18 years of age were selected by stratified multistage sampling method from urban and rural regions of 30 provinces of Iran. Meal frequency was assessed by a questionnaire prepared based on global school-based student health survey. Physical measurements included height, weight, waist circumference, systolic blood pressure (SBP), and diastolic blood pressure (DBP).

RESULTS

The participation rate was 90.6% including 49.24% girls and 75.5% urban residents. Skipping breakfast and dinner were more frequent in girls than in boys (71.6% vs. 64.1%, 91.2% vs. 86.9%, respectively, P<0.05). Overweight, obesity, and abdominal obesity were more prevalent in those who had two meals, one meal, or very low intake (P<0.001) than those had three meals. There were no significant differences in SBP, DBP, and blood pressure across to different meal frequency groups (P>0.05). Students who had very low intake and one meal per week had a higher risk of abdominal obesity compared with those who had three meals (OR 1.7, 95% CI: 1.3-2.3, and OR 1.6, 95% CI: 1.4-2.0, respectively).

CONCLUSIONS

An inverse significant association between higher meal frequency and anthropometric indices was observed. Therefore, encouraging children and adolescents for regular meal intake should be considered as a health priority in the pediatric population.

Self-Reported Eating-Occasion Frequency and Timing are Reproducible and Relatively Valid in the American Cancer Society Cancer Prevention Study-3 Diet Assessment Substudy

BACKGROUND

Accurate assessment of eating-occasion behaviors, such as timing, frequency, and consumption intervals, is important for evaluating associations with obesity and other chronic diseases.

OBJECTIVES

The main objective of this study was to assess the relative validity of a 24-hour grid approach to assess eating-occasion timing and frequency in comparison to data derived from repeated 24-hour dietary recalls (DRs). A second objective was to assess the 1-year test-retest reproducibility of the 24-hour grid.

METHODS

Between 2015 and 2016, 626 participants in the Cancer Prevention Study-3 (CPS-3) Diet Assessment Substudy (mean age, 52 years; age range, 31-70 years; 64% female; 64% non-Hispanic white, 22% non-Hispanic black, 14% Hispanic) completed 2 grids and up to 6 unannounced, telephone, interviewer-administered DRs over 1 year. Spearman correlations (ρ; 95% CIs) were calculated to assess reproducibility between the repeated eating-occasion grid-derived variables (e.g., numbers of snacks and meals per day, timing of eating occasions) and to assess relative validity by comparing the meal grid and DR-derived summary data separately for weekdays and weekend days.

RESULTS

Reproducibility correlations for eating-occasion variables derived from the eating-occasion grids completed 1 year apart were ≥0.5 for the majority of variables analyzed for both weekdays and weekend days, including numbers of snacks and meals per day and timing of the first and last eating occasions of the day. Relative validity was highest among weekday variables and was ≥0.5 for the majority of variables, with correlations ranging from ρ values of 0.32 (number of meals per day) to 0.68 (hour of the first eating occasion).

CONCLUSIONS

These findings suggest the eating-occasion grid used in CPS-3 has good reproducibility over 1 year and yields estimates comparable to those from a more detailed method of assessment of eating timing and frequency.

Eating frequency has an inverse correlation with adiposity measures and non-invasive arterial stiffness parameters in healthy adult people

BACKGROUND

Lifestyle modifications have been recommended as an essential treatment approach for cardiovascular diseases. Recent studies have shown that eating frequency (EF) correlates with hypertension and related risk of organ damage. This study aimed to examine critical clinical implications to evaluate the association of EF with arterial stiffness parameters as an early marker of atherosclerosis manifestations.

METHODS

A cross-sectional descriptive study was performed on 658 participants of the PERSIAN Organizational Cohort study in Mashhad, aged 30-70 years. Arterial stiffness was assessed by measurement markers of arteriosclerosis, including arterial age, augmentation index (AIx), augmentation pressure (AP), carotid-femoral pulse wave velocity (Cf-PWV), and central blood pressure. Differences in anthropometric indices, blood indices, and arterial stiffness parameters were evaluated across EF groups.

RESULTS

Our data demonstrate that EF was positively correlated with total daily energy intake, and favourable profiles of adiposity and blood lipids. Subjects with an increased EF, had significantly lower AIx, AP, Arterial Age and Central blood pressure (P for trend<0.001) as compared to Lowest EF and not significant with PWV (P for trend, 0.19). Arterial stiffness was also significantly lower in those with increased EF compared with subjects with low EF. By Linear regression analysis, after adjustment for Confounding factors, except PWV, EF showed the associations with all of the non-invasive arterial stiffness parameters.

CONCLUSION

Increased EF is associated with a lower wave reflection and blood pressure in the central arteries.

Association between Diet-related Behaviour and Risk of Colorectal Cancer: A Scoping Review

Individual dietary patterns may be influenced by diet-related behaviours, which may eventually play a significant role in contributing to colorectal cancer risk. As nearly half of colorectal cancer cases can be prevented through diet and lifestyle modification, in this study, we aimed to present an overview of the literature on diet-related behaviour and its effect on colorectal cancer risk among adults. Articles published from 2011 until July 2021 were selected. Out of the 1,198 articles retrieved, 25 were analyzed. There were 16 case-control studies, and nine of them were cohort studies. As a finding, the instruments used in this review were food frequency questionnaires (n = 23), followed by a semi-structured interview (n = 1), and diet records (n = 1). We demonstrated that unhealthy diet-related behaviours are linked to an increased risk of colorectal cancer in adults and those food frequency questionnaires or food records are common instruments used to collect diet-related behaviours. This article imparts the research trends and directions of colorectal cancer risk factors and shows that diet-related behaviour varies and changes over time.

Wearable Cameras Reveal Large Intra-Individual Variability in Timing of Eating among Young Adults

Studies have shown that young adults follow less structured eating patterns compared with older cohorts. This may have implications for dietary assessment methods which rely on memory and structured meal patterns. Our aim was to describe the intra-individual variation of eating times in young adults aged 18−30 years. Participants (n = 41) wore an Autographer camera that captured first-person perspective images every 30 s for three consecutive days. All images were timestamped and those showing food consumption were used to extract data such as the timing of the first and last eating occasions (EOs), number of EOs per day, and length of eating window. Intra-individual variability was calculated from these data using composite phase deviation (CPD) and coefficient of variation (CV). The number of individuals with high or very high variability was 28 and 18 for timing of first and last EOs, respectively (CPD > 1.70), and 27 and 17 for number of EOs and eating window, respectively (CV > 20%). In this sample of young adults, the lack of regularity in eating patterns should be considered when selecting a dietary assessment method.

Eating architecture in adults at increased risk of type 2 diabetes: associations with body fat and glycaemic control

Eating architecture is a term that describes meal frequency, meal timing and meal size and the daily variation in each of these. The aim of this study was to determine the relationship between components of eating architecture on body fat and markers of glycaemic control in healthy adults at increased risk of type 2 diabetes (T2DM). Participants (n 73, 39 males, age 58·8 (8·1) years, BMI 33·4 (4·4) kg/m²) recorded food intake and wore accelerometers and continuous glucose monitors (CGM) for 7-14 d under free-living conditions. Body fat and glycated Hb (HbA1c) were also measured. The mean and day-to-day variation (calculated as the standard deviation during the monitoring period) of each component of eating architecture were calculated. Multivariable linear regression models were constructed for three separate outcome variables (body fat mass, mean CGM glucose and HbA1c) for each component of eating architecture before and after adjustment for confounders. Higher variability in the time of first meal consumption was associated with increased body fat mass after adjusting for confounders (β = 0·227, 95 % CI: 0·019, 0·434, P = 0·033). Increased variability in the time lag from waking to first meal consumption was also positively associated with increased HbA1c after adjustment (β = 0·285, 95 % CI: 0·040, 0·530, P = 0·023). Low day-to-day variability in first meal consumption was associated with lower body fat and improved glucose control in adults at increased risk of T2DM. Routine consumption of meals may optimise temporal regulation to anticipate and respond appropriately to a glucose challenge.

Implications of Dietary Intake and Eating Behaviors for People with Serious Mental Illness: A Qualitative Study

The impact of poor diet quality and nutritional inadequacies on mental health and mental illness has recently gained considerable attention in science. As the opinions and experiences of people living with serious mental illness on dietary issues are unknown, we aimed to understand the role of nutrition in a biopsychosocial approach. In total, 28 semi-structured interviews were conducted with people living with serious mental illness (SMI) in Australia, Germany and Austria, and a generic thematic analysis approach was applied. Four positive (positive effects on the body and mind, therapeutic effects in treating somatic illnesses, pleasure and opportunity for self-efficacy) and three negative (impairment related to mental illness and its treatment, perceived stigma and negative effects on the body and mind) implications of diet were identified. A key issue for most of the participants was the mental burden arising from their body weight. This might indicate that negative implications, such as guilt and stigma, were of primary importance for people with SMI when talking about their dietary behavior. In conclusion, diet-related support is urgently needed for people with SMI. However, especially participants from Germany and Austria reported that this is not yet widely available in mental health settings, leading to hopelessness and resignation.

The association between long-term night shift work and metabolic syndrome: a cross-sectional study of male railway workers in southwest China

OBJECTIVES

Metabolic syndrome (MetS) increases the risk of new diabetes and cardiovascular disease. Night shift work (NSW) may influence metabolic disturbance and lead to MetS. This study aims to investigate the association between long-term NSW (≥ 10 years) and MetS combined with its components in male railway workers in southwest China.

METHODS

11,023 male railway workers with long-term NSW of more than 10 years in the Physical Examination Center of the Affiliated Hospital of Chengdu University were enrolled. The basic data were collected by investigators and blood test results were collected. The primary outcome was the prevalence of metabolic syndrome. The results were analyzed using statistical software SPSS 22.0.

RESULTS

In total, 11,023 people over the age of 40 with more than 10 years of working experience were enrolled, and 4759 (43.2%) participants had a diagnosis of MetS. The basic data indicated that night shift workers tended to be younger, shorter working years, but with higher body mass index and longer hip circumference (p < 0.05). The adjusted analysis revealed that there was no significant association between NSW and metabolic syndrome (OR 1.03, 95% CI 0.94-1.12, p = 0.543). NSW was associated with SBP ≥ 130 mmHg (OR 1.11, 95% CI 1.02-1.21, p < 0.001) and waist circumference ≥ 90 cm (OR 1.11, 95% CI 1.02-1.21, p < 0.001).

CONCLUSIONS

Long-term night shift workers had a higher prevalence of MetS. However, long-term NSW is not associated with a significantly increased risk of metabolic syndrome in male railway workers in southwest China. Long-term NSW is associated with elevated SBP, and waist circumference increase.

Eating patterns in a nationwide sample of Japanese aged 1-79 years from MINNADE study: eating frequency, clock time for eating, time spent on eating and variability of eating patterns

OBJECTIVE

Although there is growing evidence suggesting that eating patterns are important determinants of health status, comprehensive information on patterning of eating behaviours is almost lacking. The aim of this cross-sectional study was to describe eating patterns in Japan.

DESIGN

Information on actual eating behaviours was collected using 2-d dietary record in each season over a year (total 8 d). Eating occasions were defined as any discrete intake occasion (with a discrete start clock time and name) except for eating occasions consisting of water only, which were excluded.

SETTING

Japan.

PARTICIPANTS

A nationwide sample of 4032 Japanese aged 1-79 years.

RESULTS

The mean value of eating frequency of meals (i.e. breakfast, lunch and dinner), snacks and total eating occasions was 2·94, 1·74 and 4·68 times/d, respectively. The mean clock time for the start of breakfast, lunch and dinner was 07.24, 12.29 and 19.15 h, respectively. The mean time spent consuming breakfast, lunch, dinner and snacks was 19, 25, 34 and 27 min/d, respectively. On average, variability (i.e. average of absolute difference from mean) of meal frequency was small compared with that of snack frequency and total eating frequency. Both mean variability of clock time for the start of eating (<1 h) and mean variability of time spent on meals (<10 min/d) were also small. Conversely, mean variability of time spent on snacks was large (>18 min/d).

CONCLUSION

The present findings serve as both a reference and an indication for future research on patterning of eating behaviours.

Meal Timing, Meal Frequency and Metabolic Syndrome

Individuals with metabolic syndrome have increased risk for developing health conditions, including cardiovascular diseases and stroke. Modifiable risk factors, such as exercise and diet, are key components in the prevention and control of metabolic syndrome. Specifically, dietary patterns and habits are extremely successful in controlling more than one of the metabolic syndrome risk factors. Meal timing and frequency have been associated with type 2 diabetes, cardiovascular diseases, and other chronic conditions. However, there is limited evidence linking metabolic syndrome to meal timing and meal frequency. This review summarizes and discusses how meal timing and frequency impact metabolic outcomes in adults.

Effects of chronically skipping meals on atrial fibrillation risk

Atrial fibrillation is the most common form of arrhythmia and can result in significant morbidity and mortality. While there are many potential causes of atrial fibrillation that have been well studied, this work considers the potential effect of chronically skipping meals on the development of atrial fibrillation. The authors discuss the various processes that skipping meals initiates in the body that may ultimately result in atrial fibrillation. Through a better understanding of the various disease pathophysiologies that can contribute to the development of atrial fibrillation, this narrative review may help lead to more advanced therapeutic and preventive approaches.

Young people and adolescents have more irregular meals during the COVID-19 pandemic: A nested case-control study on chrono-nutrition before and during the COVID-19 pandemic

Chrono-nutrition is an emerging field of research that includes three aspects of time: (1) regularity, (2) frequency, and (3) clock time. Due to the COVID-19 pandemic and the implemented lockdown, daily routines were disrupted, which presented a unique opportunity to investigate chrono-nutrition, in particular in adolescents. A nested case-control study was conducted and information on chrono-nutrition was collected via an anonymous online questionnaire including 99 participants aged 13 to 20 years (N = 43 before the COVID-19 pandemic and N = 56 during the COVID-19 pandemic). Differences in chrono-nutrition were tested with chi-square and Mann-Whitney U. During the COVID-19 pandemic, participants consumed their breakfast less regularly (34%) compared with participants before the COVID-19 pandemic (65%) (P = .003). Additionally, during the COVID-19 pandemic, participants consumed snacks in the morning (26% vs. 60%, P = .001), afternoon (19% vs. 81%, P < .000), and evening (22% vs. 84%, P < .001) less regularly. However, the frequency in afternoon (4.9 ± 2.2 times per week vs. 3.8 ± 1.9 times per week, P = .002) and evening snacks (4.4 ± 2.4 times per week vs. 3.4 ± 2.0 times per week, P = .02) was higher for participants during the COVID-19 pandemic. We also observed that participants reported more sleeping problems during the COVID-19 pandemic (34% vs. 14%; P = .07). This study in 99 young people and adolescents suggests that meal regularity declined during the COVID-19 pandemic, while meal frequency, especially snack consumption, increased. This highlights the importance of maintaining a regular daily structure to avoid excessive energy intake via snacks.

A Time to Rest, a Time to Dine: Sleep, Time-Restricted Eating, and Cardiometabolic Health

Cardiovascular disease (CVD) poses a serious health and economic burden worldwide. Modifiable lifestyle factors are a focus of research into reducing the burden of CVD, with diet as one of the most investigated factors. Specifically, the timing and regularity of food intake is an emerging research area, with approaches such as time-restricted eating (TRE) receiving much attention. TRE involves shortening the time available to eat across the day and is associated with improved CVD outcomes compared with longer eating windows. However, studies that have examined TRE have not considered the impact of sleep on CVD outcomes despite recent evidence showing that sleep duration can influence the timing and amount of food eaten. In this article, we argue that as TRE and sleep influence each other, and influence the same cardiometabolic parameters, experiencing inadequate sleep may attenuate any positive impact TRE has on CVD. We examine the relationship between TRE and CVD, with sleep as a potential mediator in this relationship, and propose a research agenda to investigate this relationship. This will provide necessary evidence to inform future interventions aimed at reducing the burden of CVD.

Impact of isoenergetic intake of irregular meal patterns on thermogenesis, glucose metabolism, and appetite: a randomized controlled trial

BACKGROUND

Evidence is emerging that interdaily meal pattern variability potentially affects response such as thermic effect of food (TEF), macronutrient metabolism, and appetite.

OBJECTIVES

To investigate the effect of irregular meal pattern on TEF, glucose, insulin, lipid profile, and appetite regulation in women who are overweight or with obesity and confirmed insulin resistance.

DESIGN

In a randomized crossover trial, 9 women [mean ± SD BMI (in kg/m2): 33.3 ± 3.1] with confirmed insulin resistance consumed a regular (14 d; 6 meals/d) and an irregular (14 d; 3-9 meals/d) meal pattern separated by a 14-d washout interval. Identical foods were provided during the interventions, and at the start and end of each meal pattern, participants attended the laboratory after an overnight fast. Energy expenditure, glucose, insulin, lipids, adiponectin, leptin, glucagon-like peptide 1 (GLP-1), peptide YY (PYY), and ghrelin were measured at baseline and for 3 h after consumption of a test drink, after which an ad libitum test meal was offered. Subjective appetite ratings were recorded before and after the test drink, after the ad libitum meal, and during the intervention. Continuous interstitial glucose monitoring was undertaken for 7 consecutive days during each intervention.

RESULTS

TEF (over 3 h) was significantly lower postirregular intervention compared with postregular (97.7 ± 19.2 kJ*3 h in postregular visit and 76.7 ± 35.2 kJ*3 h in postirregular visit, paired t test, P = 0.048). Differences in HOMA-IR between the 2 interventions (3.3 ± 1.7 and 3.6 ± 1.6 in postregular and postirregular meal pattern, respectively) were not significant. Net incremental AUC for GLP-1 concentrations (over 3 h) for the postregular meal pattern were higher (864.9 ± 456.1 pmol/L*3 h) than the postirregular meal pattern (487.6 ± 271.7 pmol/L*3 h, paired t test, P = 0.005).

CONCLUSIONS

Following a 14-d period of an irregular meal pattern, TEF was significantly less than following a regular meal pattern, potentially compromising weight management if sustained long term. This study was registered at www.clinicaltrials.gov as NCT02582606.

The association between meal regularity and weight loss among women in commercial weight loss programs

BACKGROUND/OBJECTIVES

While many obesity studies have pointed out the importance of meal regularity, few have conducted empirical analyses using data from food diaries. We examined the association between meal regularity (i.e., meal time regularity [MTR] and calorie intake regularity [CIR]) and weight loss.

SUBJECTS/METHODS

We collected food diary data from 637 women who had participated in commercial weight loss programs for 28–168 days (4–24 weeks). This study defined “meal regularity” in terms of two concepts: MTR and CIR. MTR refers to how regularly people eat their meals (i.e., at certain times each day), whereas CIR refers to how regularly people consume a certain amount of calories at each meal. We conducted multiple regression analyses.

RESULTS

MTR (model 1: β = −2,576.526, P < 0.001; model 2: β = −1511.447, P < 0.05; model 3: β = −1,721.428, P < 0.05) and CIR (model 1: β = −1,231.551, P < 0.01; model 2: β = −2,082.353, P < 0.001; model 3: β = −1,343.490, P < 0.01) turned out to be significant determinants of the amount of weight loss in breakfast, lunch, and dinner contexts. While meal regularity (i.e., MTR and CIR) was significantly associated with weight loss, daily calorie intake from meals was not significantly associated with the amount of weight loss (model 1: β = 0.13, P > 0.05; model 2: β = 0.11, P > 0.05; model 3: β = 0.14, P > 0.05). Subjects who consumed an equal amount of calories per meal throughout the day lost more weight than those who did not (model 4: β = −3,675.51, P < 0.001).

CONCLUSIONS

Eating each meal (i.e., breakfast, lunch, and dinner) at a certain time every day may increase weight loss success. Also, consuming the same amount of calories at each meal may help weight loss success.

COVID-19 and changes in Korean consumers' dietary attitudes and behaviors

BACKGROUND/OBJECTIVES

The coronavirus disease 2019 (COVID-19) outbreak has dramatically changed nearly every aspect of our lives. Although Dietary lifestyle includes attitudes and behaviors to meet their most basic needs, but few studies have examined the pattern of changes in dietary lifestyle driven by COVID-19. This study explores changes in dietary attitudes and behaviors among Korean consumers after COVID-19.

SUBJECTS/METHODS

An online survey was conducted with 549 Korean adults aged 20 and older to identify general demographics and changes in dietary attitudes and behaviors. Data were collected from Oct 12 to Oct 18, 2020. Frequency, percentage, and mean values were calculated and a K-means cluster analysis was performed to categorize consumers based on the 5S of dietary attitudes (i.e., savor-oriented, safety-oriented, sustainability-oriented, saving-oriented, and socializing-oriented).

RESULTS

Findings indicate consumers considered safety, health, and freshness to be most important when choosing groceries and prepared meal such as home meal replacement and delivery food. Among the types of services, a large proportion of consumers increased their delivery and take-out services. Regarding retail channels, the increase in the use of online retailers was remarkable compared to offline retailers. Finally, consumers were classified into four segments based on changes in dietary attitudes: “most influenced,” “seeking safety and sustainability,” “abstaining from savor and socializing,” and “least influenced.” Each type of consumer exhibited statistically significant differences by sex, age, household composition, presence of disease, and perceived risk of COVID-19.

CONCLUSIONS

This exploratory study provides initial insights for future research by identifying various aspects of dietary attitudes and behaviors among Korean consumers after COVID-19.

Association between daily number of eating occasions with fasting glucose and insulin sensitivity in adults from families at high risk for type 2 diabetes in Europe: the Feel4Diabetes Study

OBJECTIVE

The aim of this study was to examine the association between the number of times one eats daily (termed eating occasions [EO]) with indices of glycemic control and insulin resistance (IR) in a large sample of adults from families at high risk for type 2 diabetes mellitus (T2DM) from six European countries. The study also considered sex and socioeconomic status (SES).

METHODS

Standardized questionnaires and procedures were used to assess sociodemographic characteristics, dietary intake, sedentary behavior, and anthropometric and biochemical indices. Univariate analysis of variance was used to investigate associations of daily EOs with fasting glucose (FG), fasting insulin (FI), and IR.

RESULTS

In 1552 adults (41.6 ± 7.2 y), three to four daily EOs rather than less than three were inversely associated with FG (β = -2.598; 95% confidence interval [CI], -4.521 to -0.675), independent of age, body mass index (BMI), dietary quality, and sedentary time. In women, three to four EOs per day were also associated with FG (β = -3.071; 95% CI to -5.573 to -0.570) independently of the mentioned confounders. In high SES participants, having more than four EOs per day had an inverse association with FI (β = -1.348; 95% CI to -2.583 to -0.114). No such associations were observed in men or in low SES participants.

CONCLUSION

In adults at high risk for T2DM, and especially in women, having three to four daily EOs was inversely associated with FG, whereas in high SES participants, more than four EOs was associated with FI. Future studies should further elucidate the underlying mechanisms and offer insight into the optimum number of daily EOs for the prevention of T2DM especially in men and in adults with low SES where the number of daily EOs was not found to be significantly related to glycemic indices.

Sleep and circadian rhythms: pillars of health-a Keystone Symposia report

The human circadian system consists of the master clock in the suprachiasmatic nuclei of the hypothalamus as well as in peripheral molecular clocks located in organs throughout the body. This system plays a major role in the temporal organization of biological and physiological processes, such as body temperature, blood pressure, hormone secretion, gene expression, and immune functions, which all manifest consistent diurnal patterns. Many facets of modern life, such as work schedules, travel, and social activities, can lead to sleep/wake and eating schedules that are misaligned relative to the biological clock. This misalignment can disrupt and impair physiological and psychological parameters that may ultimately put people at higher risk for chronic diseases like cancer, cardiovascular disease, and other metabolic disorders. Understanding the mechanisms that regulate sleep circadian rhythms may ultimately lead to insights on behavioral interventions that can lower the risk of these diseases. On February 25, 2021, experts in sleep, circadian rhythms, and chronobiology met virtually for the Keystone eSymposium "Sleep & Circadian Rhythms: Pillars of Health" to discuss the latest research for understanding the bidirectional relationships between sleep, circadian rhythms, and health and disease.

Content Validation of a Chrononutrition Questionnaire for the General and Shift Work Populations: A Delphi Study

Unusual meal timing has been associated with a higher prevalence of chronic disease. Those at greater risk include shift workers and evening chronotypes. This study aimed to validate the content of a Chrononutrition Questionnaire for shift and non-shift workers to identify temporal patterns of eating in relation to chronotype. Content validity was determined using a Delphi study of three rounds. Experts rated the relevance of, and provided feedback on, 46 items across seven outcomes: meal regularity, times of first eating occasion, last eating occasion, largest meal, main meals/snacks, wake, and sleep, which were edited in response. Items with greater than 70% consensus of relevance were accepted. Rounds one, two, and three had 28, 26, and 24 experts, respectively. Across three rounds, no outcomes were irrelevant, but seven were merged into three for ease of usage, and two sections were added for experts to rate and comment on. In the final round, all but one of 29 items achieved greater than 70% consensus of relevance with no further changes. The Chrononutrition Questionnaire was deemed relevant to experts in circadian biology and chrononutrition, and could represent a convenient tool to assess temporal patterns of eating in relation to chronotype in future studies.

Variability in Daily Eating Patterns and Eating Jetlag Are Associated With Worsened Cardiometabolic Risk Profiles in the American Heart Association Go Red for Women Strategically Focused Research Network

Background

Sleep variability and social jetlag are associated with adverse cardiometabolic outcomes via circadian disruption. Variable eating patterns also lead to circadian disruption, but associations with cardiometabolic health are unknown.

Methods and Results

Women (n=115, mean age: 33±12 years) completed a 1‐week food record using the Automated Self‐Administered 24‐Hour Dietary Assessment Tool at baseline and 1 year. Timing of first and last eating occasions, nightly fasting duration, and %kcal consumed after 5 pm (%kcal 5 pm) and 8 pm (%kcal 8 pm) were estimated. Day‐to‐day eating variability was assessed from the SD of these variables. Eating jetlag was defined as weekday‐weekend differences in these metrics. Multivariable‐adjusted linear models examined cross‐sectional and longitudinal associations of day‐to‐day variability and eating jetlag metrics with cardiometabolic risk. Greater jetlag in eating start time, nightly fasting duration, and %kcal 8 pm related to higher body mass index and waist circumference at baseline (P<0.05). In longitudinal analyses, a 10% increase in %kcal 8 pm SD predicted increased body mass index (β, 0.52; 95% CI, 0.23–0.81) and waist circumference (β, 1.73; 95% CI, 0.58–2.87); greater %kcal 8 pm weekday‐weekend differences predicted higher body mass index (β, 0.25; 95% CI, 0.07–0.43). Every 30‐minute increase in nightly fasting duration SD predicted increased diastolic blood pressure (β, 0.95; 95% CI, 0.40–1.50); an equivalent increase in nightly fasting duration weekday‐weekend differences predicted higher systolic blood pressure (β, 0.58; 95% CI, 0.11–1.05) and diastolic blood pressure (β, 0.45; 95% CI, 0.10–0.80). Per 10% increase in %kcal 5 pm SD, there were 2.98 mm Hg (95% CI, 0.04–5.92) and 2.37mm Hg (95% CI, 0.19–4.55) increases in systolic blood pressure and diastolic blood pressure; greater %kcal 5 pm weekday‐weekend differences predicted increased systolic blood pressure (β, 1.83; 95% CI, 0.30–3.36). For hemoglobin A1c, every 30‐minute increase in eating start and end time SD and 10% increase in %kcal 5 pm SD predicted 0.09% (95% CI, 0.03–0.15), 0.06% (95% CI, 0.001–0.12), and 0.23% (95% CI, 0.07–0.39) increases, respectively.

Conclusions

Variable eating patterns predicted increased blood pressure and adiposity and worse glycemic control. Findings warrant confirmation in population‐based cohorts and intervention studies.

A scoping review of chronotype and temporal patterns of eating of adults: tools used, findings, and future directions

Circadian rhythms, metabolic processes and dietary intake are inextricably linked. Timing of food intake is a modifiable temporal cue for the circadian system and may be influenced by numerous factors, including individual chronotype - an indicator of an individual's circadian rhythm in relation to the light-dark cycle. This scoping review examines temporal patterns of eating across chronotypes and assesses tools that have been used to collect data on temporal patterns of eating and chronotype. A systematic search identified thirty-six studies in which aspects of temporal patterns of eating, including meal timings; meal skipping; energy distribution across the day; meal frequency; time interval between meals, or meals and wake/sleep times; midpoint of food/energy intake; meal regularity; and duration of eating window, were presented in relation to chronotype. Findings indicate that, compared with morning chronotypes, evening chronotypes tend to skip meals more frequently, have later mealtimes, and distribute greater energy intake towards later times of the day. More studies should explore the difference in meal regularity and duration of eating window amongst chronotypes. Currently, tools used in collecting data on chronotype and temporal patterns of eating are varied, limiting the direct comparison of findings between studies. Development of a standardised assessment tool will allow future studies to confidently compare findings to inform the development and assessment of guidelines that provide recommendations on temporal patterns of eating for optimal health.

Biological Rhythm and Chronotype: New Perspectives in Health

The circadian rhythm plays a fundamental role in regulating biological functions, including sleep–wake preference, body temperature, hormonal secretion, food intake, and cognitive and physical performance. Alterations in circadian rhythm can lead to chronic disease and impaired sleep. The circadian rhythmicity in human beings is represented by a complex phenotype. Indeed, over a 24-h period, a person’s preferred time to be more active or to sleep can be expressed in the concept of morningness–eveningness. Three chronotypes are distinguished: Morning, Neither, and Evening-types. Interindividual differences in chronotypes need to be considered to reduce the negative effects of circadian disruptions on health. In the present review, we examine the bi-directional influences of the rest–activity circadian rhythm and sleep–wake cycle in chronic pathologies and disorders. We analyze the concept and the main characteristics of the three chronotypes.

The effect of meal frequency on biochemical cardiometabolic factors: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Although several randomized controlled trials (RCTs) have supported the beneficial effects of higher meal frequency (MF) on cardiometabolic risk factors, the putative effects of higher MF on health remain inconclusive. This study systematically reviewed the evidence from RCTs of the effect of higher compared with lower MF on the blood lipid profile, glucose homeostasis, and adipokines.

METHODS

PubMed, Scopus, ISI Web of Science, and the Cochrane database were searched up to October 2020 to retrieve relevant RCTs. A DerSimonian and Laird random effects model was used to pool mean differences and 95% CI for each outcome. The quality of studies and evidence was assessed through standard methods.

RESULTS

Twenty-one RCTs (686 participants) were included in this meta-analysis. Overall results showed a significant improvement in total cholesterol [weighted mean difference (WMD) = -6.08 mg/dl; 95% CI: -10.68, -1.48; P = 0.01; I² = 88%], and low-density cholesterol (LDL-C) (WMD = -6.82 mg/dl; 95% CI: -10.97, -1.60; P = 0.009; I² = 85.7%), while LDL-C to high-density cholesterol ratio (LDL-C: HDL-C) increased (WMD = 0.22; 95% CI: 0.07, 0.36; P = 0.003; I² = 0.0%) in higher MF vs. lower MF. No significant effects were found on measures of glycemic control, apolipoproteins-A1 and B, or leptin. In subgroup analyses, higher MF significantly reduced serum triglyceride (TG), and increased HDL-C, compared with lower MF in interventions > 12 weeks, and decreased serum TC and LDL-C in healthy participants. A significant reduction in LDL-C also was observed in studies where the same foods given both arms, simply divided into different feeding occasions, and in feeding studies, following higher MF compared to lower MF.

CONCLUSION

Our meta-analysis found that higher, compared with lower MF may improve total cholesterol, and LDL-C. The intervention does not affect measures of glycemic control, apolipoproteins-A1 and B, or leptin. However, the GRADE ratings of low credibility of the currently available evidence highlights the need for more high-quality studies in order to reach a firm conclusion.

Rest-activity rhythms in emerging adults: implications for cardiometabolic health

Emerging adulthood (18-25 years) represents a window of opportunity to modify the trajectory of cardiometabolic disease risk into older adulthood. Not known is the extent to which rest-activity rhythms (RAR) may be related to biomarkers of cardiometabolic health in this population. In this cross-sectional, observational study, 52 healthy emerging adults wore wrist accelerometers (14 consecutive days; 24 h/day) for assessment of nonparametric RAR metrics, including interdaily stability (IS; day-to-day RAR consistency), intradaily variability (IV; within-day RAR fragmentation), and relative amplitude (RA; robustness of RAR), as well as autocorrelation (correlation of rest/activity levels at 24-h lag-times). Cardiometabolic biomarkers, including body mass index (BMI), body fat percentage, blood pressure (BP), fasting lipids, glucose, and C-reactive protein (CRP) were assessed. Additional measures including physical activity, sleep duration, and habitual caffeine and alcohol consumption were also evaluated. A series of multivariable regression models of cardiometabolic biomarkers were used to quantify associations with RAR metrics. On average, participants were 20 ± 1 years of age (21 males, 31 females), non-obese, and non-hypertensive. All were nonsmokers and free of major diseases or conditions. In separate models, which adjusted for sex, BMI, moderate-vigorous physical activity, sleep duration, caffeine, and alcohol consumption, IS was inversely associated with total cholesterol (p ≤ 0.01) and non-HDL cholesterol (p < .05), IV was positively associated with CRP (p < .05), and autocorrelation was inversely associated with total cholesterol (p < .05) and CRP (p < .05). Conversely, associations between RA and cardiometabolic biomarkers were nonsignificant after adjustment for BMI, alcohol, and caffeine consumption. In conclusion, RAR metrics, namely, a higher IS, lower IV, and higher autocorrelation, emerged as novel biomarkers associated with more favorable indices of cardiometabolic health in this sample of apparently healthy emerging adults.

Stability of the timing of food intake at daily and monthly timescales in young adults

Cross-sectional observations have shown that the timing of eating may be important for health-related outcomes. Here we examined the stability of eating timing, using both clock hour and relative circadian time, across one semester (n = 14) at daily and monthly time-scales. At three time points ~ 1 month apart, circadian phase was determined during an overnight in-laboratory visit and eating was photographically recorded for one week to assess timing and composition. Day-to-day stability was measured using the Composite Phase Deviation (deviation from a perfectly regular pattern) and intraclass correlation coefficients (ICC) were used to determine individual stability across months (weekly average compared across months). Day-to-day clock timing of caloric events had poor stability within individuals (~ 3-h variation; ICC = 0.12-0.34). The timing of eating was stable across months (~ 1-h variation, ICCs ranging from 0.54-0.63), but less stable across months when measured relative to circadian timing (ICC = 0.33-0.41). Our findings suggest that though day-to-day variability in the timing of eating has poor stability, the timing of eating measured for a week is stable across months within individuals. This indicates two relevant timescales: a monthly timescale with more stability in eating timing than a daily timescale. Thus, a single day's food documentation may not represent habitual (longer timescale) patterns.

The Study of Relationship between Nutritional Behaviors and Metabolic Indices: A Systematic Review

Metabolic indices are the wide range of characteristic factors, which can be changed during several medical conditions such as metabolic syndrome. Nutrition and related behaviors are one of the main aspects of human lifestyle which recent investigations have recognized their roles in the development of metabolic disorders. According to the spread of risky nutritional habits/behaviors due to the changes in lifestyle, and its importance in the prevalence of metabolic disorders, the authors attempted to summarize these evidences in a systematic review. The present study is a systematic review that encompasses those studies investigating the association between metabolic indices and nutritional/dietary behaviors published in two international databases in recent 11 years. Twenty-nine related articles were considered and their data were extracted. The relation between food choices and metabolic indices is more frequent in studies. While, inhibition and abstinent and eating together were two behavioral sets with the smallest share of research. Anthropometric indices have the highest rate in the evaluations. Finding the links between nutritional behavior and metabolic indices will be the key point in selecting the different types of interventions. These results will guide therapists to the accurate recognition of metabolic effects in targeting behavior for their intervention.

FREQUENCY OF MEALS CONSUMED BY BRAZILIAN ADOLESCENTS AND ASSOCIATED HABITS: SYSTEMATIC REVIEW

OBJECTIVE

To analyze the studies that identified the frequency of meals ingested by Brazilian adolescents and associated habits.

DATA SOURCES

A systematic search was made in the databases and electronic databases: MEDLINE/PubMed, The Latin American and Caribbean Center of Information in Health Sciences (BIREME), Scopus, Web of Science and Embase, with articles published between January/2007 until December/2017, which addressed the evaluation of the frequency of meals performed by adolescents, considering or not associations with eating patterns and meal replacement.

DATA SYNTHESIS

6,608 studies were obtained through the search and nine were included in this review, all of them with a cross-sectional design. Eight studies used school surveys and only one was a population survey. Seven studies evaluated the frequency of the main daily meals that ranged from 47.0 to 79.0% at breakfast, from 65.0 to 98.4% at lunch, and from 51.0 to 94.0% at dinner. Five studies identified the frequencies of consumption of snacks between meals, finding higher values for afternoon snack (variation from 42.0 to 78.0%). Regarding the substitution of meals for snacks, in three of the four selected studies; it was observed that this practice occurred mainly in substitution of dinner (24.6 to 42.0%).

CONCLUSIONS

Breakfast was the most omitted meal for adolescents, and dinner was replaced with snacks. Among the between meal snacks, the afternoon snack was the most consumed.

Low dose of luteolin activates Nrf2 in the liver of mice at start of the active phase but not that of the inactive phase

A flavone luteolin has various health-promoting activities. Several studies reported that high dose of luteolin activates the Nrf2/ARE pathway in the liver. However, the effect of the low dose of luteolin that can be taken from a dietary meal on the Nrf2 activation remain unclear. It is expected that the flavonoid metabolism possesses a circadian rhythm, since nutritional metabolism processes daily cycle. In this study we investigated whether an administration affects the Nrf2 activation. ICR mice were orally administered 0.01–10 mg/kg body weight of luteolin once a day for 7 days at two time-points: at the start of active phase (ZT12) or at that of inactive phase (ZT0). Luteolin increased the nuclear translocation of Nrf2, resulting in the increases in its target gene products HO-1 and NQO1 at ZT12 but not at ZT0. The expression level of Nrf2 was lower at ZT12 than at ZT0 in the liver. We also found that the level of luteolin aglycon in the plasma is higher at ZT12 than at ZT0. These results suggest that the low dose of luteolin can activate Nrf2 pathway and the aglycon form of luteolin may mainly contribute to activate the Nrf2 pathway at ZT12 in the liver.

Chrono-Nutrition and Diet Quality in Adolescents with Delayed Sleep-Wake Phase Disorder

Background: Delayed sleep-wake phase disorder (DSPD), characterized by delayed sleep-onset and problems with awakening in the morning, is mostly prevalent in adolescents. Several studies have suggested chrono-nutrition could present a possible modifiable risk factor for DSPD. Objective: To describe differences in chrono-nutrition and diet quality in adolescents with DSPD compared to age-related controls. Methods: Chrono-nutrition and diet quality of 46 adolescents with DSPD, aged 13–20 years, and 43 controls were assessed via questionnaires. Diet quality included the Dutch Healthy Diet index (DHD-index) and Eating Choices Index (ECI). Results were analysed using logistic regression and Spearman’s partial correlation. Results: Compared with controls, DSPD patients consumed their first food of the day significantly later on weekdays (+32 ± 12 min, p = 0.010) and weekends (+25 ± 8 min, p = 0.005). They consumed their dinner more regularly (80.4% vs. 48.8%, p = 0.002) and consumed morning-snacks less frequently (3.0 ± 2.1 days vs. 4.2 ± 1.7 days, p = 0.006). No differences in clock times of breakfast, lunch, or dinner were found. Moreover, no significant differences in overall diet quality were observed. Conclusion: This descriptive study showed chrono-nutritional differences between adolescents with and without DPSD. Further studies are needed to explore features of chrono-nutrition as a possible treatment of DPSD.

Ten-Hour Time-Restricted Eating Reduces Weight, Blood Pressure, and Atherogenic Lipids in Patients with Metabolic Syndrome

In animal models, time-restricted feeding (TRF) can prevent and reverse aspects of metabolic diseases. Time-restricted eating (TRE) in human pilot studies reduces the risks of metabolic diseases in otherwise healthy individuals. However, patients with diagnosed metabolic syndrome often undergo pharmacotherapy, and it has never been tested whether TRE can act synergistically with pharmacotherapy in animal models or humans. In a single-arm, paired-sample trial, 19 participants with metabolic syndrome and a baseline mean daily eating window of ≥14 h, the majority of whom were on a statin and/or antihypertensive therapy, underwent 10 h of TRE (all dietary intake within a consistent self-selected 10 h window) for 12 weeks. We found this TRE intervention improves cardiometabolic health for patients with metabolic syndrome receiving standard medical care including high rates of statin and anti-hypertensive use. TRE is a potentially powerful lifestyle intervention that can be added to standard medical practice to treat metabolic syndrome. VIDEO ABSTRACT.

At the Interface of Lifestyle, Behavior, and Circadian Rhythms: Metabolic Implications

Nutrient metabolism is under circadian regulation. Disruption of circadian rhythms by lifestyle and behavioral choices such as work schedules, eating patterns, and social jetlag, seriously impacts metabolic homeostasis. Metabolic dysfunction due to chronic misalignment of an organism's endogenous rhythms is detrimental to health, increasing the risk of obesity, metabolic and cardiovascular disease, diabetes, and cancer. In this paper, we review literature on recent findings on the mechanisms that communicate metabolic signals to circadian clocks and vice versa, and how human behavioral changes imposed by societal and occupational demands affect the physiological networks integrating peripheral clocks and metabolism. Finally, we discuss factors possibly contributing to inter-individual variability in response to circadian changes in the context of metabolic (dys)function.

Association between night work and dyslipidemia in South Korean men and women: a cross-sectional study

BACKGROUND

Previous studies have reported that an irregular work schedule, particularly nighttime work, is associated with an altered lipid profile. Additionally, a mismatch in circadian rhythm can affect sleeping and eating habits, leading to poor health. This study aimed to examine the association between night work and dyslipidemia among South Korean adults aged ≥30 years.

METHODS

For this study, the data of 5813 participants in the 2013-2016 Korea National Health and Nutrition Examination Survey were analyzed. Diagnoses of dyslipidemia were based on blood sampling tests of total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL) cholesterol, and triglyceride levels. Night work was defined as that conducted during evening (6 P.M.-12 A.M.) and overnight hours (12 A.M.-8 A.M.). The association between night work hours and dyslipidemia in South Korean men and women was investigated using a logistic regression analysis.

RESULTS

After adjusting for sociodemographic, economic, health-related, and nutritional factors, an association of night work with dyslipidemia was observed in male participants (odds ratio = 1.53, 95% confidence interval: 1.05-2.24). In subset analyses of male participants, night workers who skipped meals were more likely to have dyslipidemia than their day-working counterparts. Among men who slept < 7 h, night workers had a higher probability of dyslipidemia than day workers. In contrast, no statistically significant association between night work and dyslipidemia was observed in female participants, although the probability of dyslipidemia appeared to increase with advancing age. Furthermore, when women with dyslipidemia were subdivided by occupational categories, night workers in white collar positions were more likely to have dyslipidemia than their day-working counterparts.

CONCLUSION

Our study observed an association of night work with dyslipidemia, particularly in men. Although these findings may support interventions for South Korean night workers, further studies are needed for validation.

The centrality of health behaviours: A network analytic approach

OBJECTIVES

Since behavioural risk factors are the foremost causes of disability and premature mortality, developing new perspectives for understanding them is of utmost importance. This paper describes an innovative approach that conceptualizes health-related behaviours as nodes in a weighted network.

DESIGN & METHODS

Using self-reported data from a representative sample (n = 374), a network of 37 health behaviours was analysed, with the aim of identifying 'central' nodes, that is, behaviours that are likely to co-occur with others and potentially influence them.

RESULTS

In line with conservation of resources theory, the analysis indicated that behaviours related to basic physiological needs (nutrition and sleep) were most central. Behaviour centrality also varied across subpopulations: Periodic medical examinations, eating meals regularly, and sleep hygiene were more central among high- compared to low-socio-economic status participants; behaviours related to supportive social relationships and sun protection were more central among women compared to men.

CONCLUSION

By emphasizing behavioural connectivity, the approach applied herein has identified core health behaviours with potentially high impact on healthy lifestyle behaviours. Statement of Contribution What is already known on this subject? Many health behaviours are related to each other. Engagement in one health behaviour can affect engagement in other behaviours. What does this study add? Health behaviour can be viewed and analysed as a network. Sleep and nutrition behaviours are the most central behaviours in the network. Centrality varies as a function of socio-economic status and gender.

Eating patterns of Australian adults: associations with blood pressure and hypertension prevalence

PURPOSE

Eating patterns have been linked to obesity, an established risk factor for hypertension; however, their contribution to hypertension is poorly understood. This study aimed to examine associations of frequency of meals, snacks and all eating occasions (EO), and temporal eating patterns, with blood pressure (BP) and hypertension.

METHODS

Dietary data collected via two 24-h recalls during the 2011-2012 Australian National Nutrition and Physical Activity Survey (n = 4482 adults, ≥ 19 years) were analysed. Frequencies of EO, meals, and snacks were calculated. Temporal eating patterns were determined using latent class analysis. Multivariate regression models assessed associations of eating patterns with systolic BP (SBP), diastolic BP (DBP), and hypertension prevalence.

RESULTS

Among men, a higher snack frequency was inversely associated with DBP [β = - 0.59, 95% confidence interval (CI) (- 1.12, - 0.07)] and hypertension [odds ratio (OR) 0.86, 95% CI (0.75, 0.98)] after adjustment for covariates and BMI. However, these associations disappeared after additional adjustment for total energy intake and overall diet quality. Among women, a temporal eating pattern characterized by a later "lunch" meal was associated with SBP [β = 2.45, 95% CI (0.05, 4.84)], DBP [β = 1.69, 95% CI (0.25, 3.13)], and hypertension [OR = 1.49, 95% CI (1.00, 2.22)], when compared to a "conventional" eating pattern.

CONCLUSIONS

In this study, an inverse association found between snack frequency and BP among men disappeared after adjustment for dietary factors and a "later lunch" pattern was associated with higher BP in women. Future research is needed to understand the relationship and potential mechanistic pathways between eating patterns and BP.

Sleep duration, nightshift work, and the timing of meals and urinary levels of 8-isoprostane and 6-sulfatoxymelatonin in Japanese women

It has been hypothesized that disruption of circadian rhythms affects human health. Shift work and sleep deprivation are thought to disrupt the normal light-dark cycle, although the disruption due to shiftwork may be dependent on sleep deprivation. Both conditions have been suggested to be associated with an increased risk of cardiometabolic disorders. Non-photic environmental factors, such as the timing of eating, are also thought to regulate circadian rhythm and thus, may have effects on health, but the evidence from human studies is scarce. Oxidative stress is a risk factor of cardiometabolic disorders. Some laboratory studies suggest an involvement of circadian clock genes in the regulation of the redox system. The present study aimed to examine the association of sleeping habits, nightshift work, and the timing of meals with urinary levels of 8-isoprostane, a marker of oxidative stress, and 6-sulfatoxymelatonin, the principal metabolite of melatonin. Study subjects were 542 women who had previously attended a breast cancer mass screening in a community in Japan. Information on bedtimes and wake-up times, history of nightshift work, and the timing of meals was obtained by a self-administered questionnaire. The 8-isoprostane and 6-sulfatoxymelatonin were measured using the first morning void of urine and expressed per mg of creatinine. The geometric mean of 8-isoprostane levels was 12.1% higher in women with ≤6 hours of sleep than that in those with >8 hours of sleep on weekdays, and longer sleep duration on weekdays was significantly associated with lower urinary levels of 8-isoprostane after controlling for covariates (p for trend = 0.04). Women who were currently working the nightshift had a 33.3% higher geometric mean of 8-isoprostane levels than those who were not working nightshift (p = 0.03). Urinary 6-sulfatoxymelatonin levels were unrelated to sleep habits or nightshift work. Women who ate breakfast at irregular times had a 19.8% higher geometric mean of 8-isoprostane levels than those who ate breakfast at a regular time or who did not eat (p = 0.02). Women who ate nighttime snacks at irregular times had a 16.2% higher geometric mean of 8-isoprostane levels than those who did not eat nighttime snacks or who ate nighttime snacks at a regular time (p = 0.003). Among women who ate dinner at a regular time, earlier times for dinner were associated with higher 8-isoprostane and 6-sulfatoxymelatonin levels (p values for trends were 0.01 and 0.02, respectively). However, the times of dinner and nighttime snack are overlapping, and the time of last meal of the day was not associated with 8-isoprostane and 6-sulfatoxymelatonin levels. The time of breakfast or lunch was not associated with these biomarkers among women who ate the meal at regular times. Disturbing the rhythmicity of daily life may be associated with oxidative stress.