Nutrition and the circadian system. Br J Nutr. 2016;116:434-442. [PMID: 27221157 DOI: 10.1017/s0007114516002117]

Timing of exercise differentially impacts adipose tissue gain in male adolescent rats

OBJECTIVE

Circadian rhythms of metabolic, hormonal, and behavioral fluctuations and their alterations can impact health. An important gap in knowledge in the field is whether the time of the day of exercise and the age of onset of exercise exert distinct effects at the level of whole-body adipose tissue and body composition. The goal of the present study was to determine how exercise at different times of the day during adolescence impacts the adipose tissue transcriptome and content in a rodent model.

METHODS

Rats were subjected to one of four conditions during their adolescence: early active phase control or exercise (EAC or EAE; ZT13), and late active phase control or exercise (LAC or LAE; ZT23). The effects of exercise timing were assessed at the level of subcutaneous and visceral adipose tissue transcriptome, body composition, hypothalamic expression of orexigenic and anorexigenic genes, blood serum markers and 24-hour core body temperature patterns.

RESULTS

We found that late active phase exercise (ZT23) greatly upregulated pathways of lipid synthesis, glycolysis and NADH shuttles in LAE rats, compared to LAC or EAE. Conversely, LAE rats showed notably lower content of adipose tissue. In addition, LAE rats showed signs of impaired FGF21-adiponectin axis compared to other groups.

CONCLUSIONS

Finally, LAE rats showed higher post-exercise core body temperature compared to other groups. Our results thus indicate that our exercise protocol induced an unusual effect characterized by enhanced lipid synthesis but reduced adipose tissue content in late active phase but not early active phase exercise during adolescence.

Unraveling the Health Benefits and Mechanisms of Time-Restricted Feeding: Beyond Caloric Restriction

Time-restricted feeding (TRF) is a lifestyle intervention that aims to maintain a consistent daily cycle of feeding and fasting to support robust circadian rhythms. Recently, it has gained scientific, medical, and public attention due to its potential to enhance body composition, extend lifespan, and improve overall health, as well as induce autophagy and alleviate symptoms of diseases like cardiovascular diseases, type 2 diabetes, neurodegenerative diseases, cancer, and ischemic injury. However, there is still considerable debate on the primary factors that contribute to the health benefits of TRF. Despite not imposing strict limitations on calorie intake, TRF consistently led to reductions in calorie intake. Therefore, while some studies suggest that the health benefits of TRF are primarily due to caloric restriction (CR), others argue that the key advantages of TRF arise not only from CR but also from factors like the duration of fasting, the timing of the feeding period, and alignment with circadian rhythms. To elucidate the roles and mechanisms of TRF beyond CR, this review incorporates TRF studies that did not use CR, as well as TRF studies with equivalent energy intake to CR, which addresses the previous lack of comprehensive research on TRF without CR and provides a framework for future research directions.

Nutrition support in children with medical complexity and chronic critical illness: A narrative review

Children with medical complexity (CMC) and children with chronic critical illness (CCI) represent growing populations with high healthcare use and dependence on specialized care, both in the hospital and community setting. Nutrition assessment and delivery represent critical components of addressing the short-term and long-term health needs for these populations across the care continuum. This article provides a framework and reviews existing literature for the assessment of nutrition status and subsequent delivery of nutrition prescriptions in CMC and children with CCI. The specific aims are to (1) describe the epidemiology of health services experience for CMC and children with CCI, with a focus on their nutrition outcomes; (2) detail how to assess their nutrition status and energy requirements; (3) review methods of delivery of the nutrient prescription; (4) introduce perioperative considerations; (5) highlight examples of special populations of CMC and children with CCI; and (6) propose future research initiatives to improve nutrition and overall outcomes for these populations.

The association of energy or macronutrient intake in three meals with depression in adults with cardiovascular disease: the United States National Health and Nutrition Examination Survey, 2003-2018

BACKGROUND

There is growing evidence that individuals with cardiovascular disease (CVD) are more likely to develop depression. The timing of food intake can significantly alter the body's circadian rhythm and affect the occurrence of depression. Currently, it is unknown whether and how energy or macronutrient intake times are associated with depression in adults with CVD.

OBJECTIVE

To evaluate dietary energy or macronutrient intake (across three meals) associations with depression in adults with CVD in a nationally representative sample.

METHODS

The study population consisted of 3,490 U.S. adults with CVD (including 554 with depression) from the National Health and Nutrition Examination Survey 2003-2018. Energy and macronutrient intake was measured by a 24-h dietary recall, and depression was diagnosed by the Patient Health Questionnaire (PHQ-9, score ≥ 10). According to dietary energy or macronutrient intake across three meals, adults with CVD were divided into five groups. Logistic regression analysis was performed to examine associations between energy or macronutrient intake and depression after adjusting for a series of confounding factors, including age, gender, education level, household income, smoking status, drinking status, physical activity, marital status, skipping breakfast/lunch/dinner, total energy, carbohydrate, protein, dietary fiber, SFA, MUFA, and PUFA intake, T2DM and hypertension status, and BMI. Dietary substitution models were used to explore changes in depression risk when 5% dietary energy intake at dinner or lunch was substituted with energy intake at breakfast.

RESULTS

When compared with participants in the lowest quintile of breakfast energy intake, those who received energy intake in the highest quintile at breakfast were associated with lower depression risk in those with CVD, and the adjusted odds ratio (OR) was 0.71 (95% CI, 0.51 to 0.91). When compared with participants in the lowest quintile of lunch or dinner energy intake, the risk of depression did not exhibit statistical significance when lunch or dinner energy intake was in the highest quintile, and the adjusted ORs were 1.08 (95% CI, 0.65 to 1.83) and 0.92 (95% CI, 0.62 to 1.37), respectively. Isocalorically replacing 5% of total energy at dinner or lunch with breakfast was associated with 5% (OR: 0.95, 95% CI 0.93 to 0.97) and 5% (OR: 0.95, 95% CI 0.93 to 0.96) lower risk of depression, respectively.

CONCLUSIONS

High energy intake at breakfast may be associated with a lower risk of depression in those with CVD. We should focus on the potential role of breakfast energy intake in preventing the onset of depression.

LncRNA-MSTRG.19083.1 Targets NTRK2 as a miR-429-y Sponge to Regulate Circadian Rhythm via the cAMP Pathway in Yak Testis and Cryptorchidism

Long noncoding RNAs (LncRNAs) play essential roles in numerous biological processes in mammals, such as reproductive physiology and endocrinology. Cryptorchidism is a common male reproductive disease. Circadian rhythms are actively expressed in the reproductive system. In this study, a total of 191 LncRNAs were obtained from yak testes and cryptorchids. Then, we identified NTRK2's relationship to circadian rhythm and behavioral processes. Meanwhile, the ceRNA (LncRNA-MSTRG.19083.1/miR-429-y/NTRK2) network was constructed, and its influence on circadian rhythm was revealed. The results showed that NTRK2 and LncRNA-MSTRG.19083.1 were significantly upregulated, and miR-429-y was obviously decreased in cryptorchid tissue; NTRK2 protein was mainly distributed in the Leydig cells of the testis. In addition, the upregulation of the expression level of miR-429-y resulted in the significant downregulation of LncRNA and NTRK2 levels, while the mRNA and protein levels of CREB, CLOCK, and BMAL1 were significantly upregulated; the knockdown of miR-429-y resulted in the opposite changes. Our findings suggested that LncRNA-MSTRG.19083.1 competitively binds to miR-429-y to target NTRK2 to regulate circadian rhythm through the cAMP pathway. Taken together, the results of our study provide a comprehensive understanding of how the LncRNA-miRNA-mRNA networks operate when yak cryptorchidism occurs. Knowledge of circadian-rhythm-associated mRNAs and LncRNAs could be useful for better understanding the relationship between circadian rhythm and reproduction.

Impacts of circadian disruptions on behavioral rhythms in mice

Circadian rhythms are fundamental biological processes that recur approximately every 24 h, with the sleep-wake cycle or circadian behavior being a well-known example. In the field of chronobiology, mice serve as valuable model animals for studying mammalian circadian rhythms due to their genetic similarity to humans and the availability of various genetic tools for manipulation. Monitoring locomotor activity in mice provides valuable insights into the impact of various conditions or disturbances on circadian behavior. In this review, we summarized the effects of disturbance of biological rhythms on circadian behavior in mice. External factors, especially light exert a significant impact on circadian behavior. Additionally, feeding timing, food composition, ambient temperature, and physical exercise contribute to variations in the behavior of the mouse. Internal factors, including gender, age, genetic background, and clock gene mutation or deletion, are effective as well. Understanding the effects of circadian disturbances on murine behavior is essential for gaining insights into the underlying mechanisms of circadian regulation and developing potential therapeutic interventions for circadian-related disorders in humans.

Relationship with Nut Consumption for Breakfast and Postprandial Glucose, Insulin, Triglyceride Responses: A Preliminary Study from Türkiye

This study aimed to determine the effect of adding nuts to a regular breakfast on blood glucose, insulin, and triglyceride levels, and to evaluate participants' opinions by sex as a preliminary study for future studies. Data and biochemical parameters were collected through face-to-face interviews with Acibadem Hospital employees (n = 12) between April and September 2023. Participants consumed 30 g of nut-supplemented breakfasts for 4 weeks while maintaining their regular lifestyle. Blood tests and visual analog scale (VAS) parameters were assessed on intervention days. VAS scores indicated differences in meal taste, post-breakfast well-being, satiety, and meal adequacy, and for "feeling better after breakfast", and "providing better satiety", were significantly higher for the nut-supplemented breakfasts (p < 0.05), especially walnut-supplemented. Under the control of age, sex, and BMI variables in the participants, women responded better to peanut butter consumption than men in terms of blood insulin and triglyceride regulation (p < 0.05). However, triglyceride regulation in men was better managed by walnut consumption than in women. Understanding how nut-supplemented breakfasts impact blood glucose, insulin, and triglyceride levels, as well as consumer perceptions, is crucial for promoting healthier dietary choices.

Effects of caffeine intake on pupillary parameters in humans: a systematic review and meta-analysis

Caffeine is a widely used drug that broadly affects human cognition and brain function. Caffeine acts as an antagonist to the adenosine receptors in the brain. Previous anecdotal reports have also linked caffeine intake with changes in pupil diameter. By modifying the retinal irradiance, pupil diameter modulates all ocular light exposure relevant for visual (i.e., perception, detection and discrimination of visual stimuli) and non-visual (i.e., circadian) functions. To date, the extent of the influence of caffeine on pupillary outcomes, including pupil diameter, has not been examined in a systematic review. We implemented a systematic review laid out in a pre-registered protocol following PRISMA-P guidelines. We only included original research articles written in English reporting studies with human participants, in which caffeine was administered, and pupil diameter was measured using objective methods. Using broad search strategies, we consulted various databases (PsycINFO, Medline, Embase, Cochrane Library, bioRxiv and medRxiv) and used the Covidence platform to screen, review and extract data from studies. After importing studies identified through database search (n = 517 imported, n = 46 duplicates), we screened the title and abstracts (n = 471), finding 14 studies meeting our eligibility criteria. After full-text review, we excluded seven studies, leaving only a very modest number of included studies (n = 7). Extraction of information revealed that the existing literature on the effect of caffeine on pupil parameters is very heterogeneous, differing in pupil assessment methods, time of day of caffeine administration, dose, and protocol timing and design. The evidence available in the literature does not provide consistent results but studies rated as valid by quality assessment suggest a small effect of caffeine on pupil parameters. We summarize the numeric results as both differences in absolute pupil diameter and in terms of effect sizes. More studies are needed using modern pupil assessment methods, robust study design, and caffeine dose-response methodology.

Chrononutrition, eating behaviour, and metabolic health among obese patients elected for bariatric surgery

There is evidence of the impact of chrononutrition on weight loss and metabolic control. However, the precise chrononutrition behaviours that promote these benefits are not fully described, and there are doubts if chrononutrition may be related to other eating behaviour features. The main aim was to evaluate the associations between chrononutrition and eating behaviour, and their relationships with anthropometric and biochemical parameters among obese patients elected for bariatric surgery. Eighty participants (76.3% females, mean age = 45 years, mean BMI = 41.6 kg/m2) attending bariatric surgery consultations at Centro Hospitalar Universitário de São João (Porto, Portugal) were assessed regarding chrononutrition (Chrononutrition Profile - Questionnaire) and eating behaviour (Three-Factor Eating Questionnaire - R21 and General Eating Self-Efficacy Scale). Height, weight, waist circumference, and biochemical values (total, HDL and LDL cholesterol, triglycerides and glycated haemoglobin) were collected. Eating window midpoint was positively correlated with uncontrolled eating and negatively with eating self-efficacy. Sleep duration and midpoint on free days negatively correlated with eating self-efficacy, mainly due to later waking times, supporting that predominantly later energy consumption may negatively impact eating behaviour.

Circadian rhythm alterations affecting the pathology of neurodegenerative diseases

The circadian rhythm is a nearly 24-h oscillation found in various physiological processes in the human brain and body that is regulated by environmental and genetic factors. It is responsible for maintaining body homeostasis and it is critical for essential functions, such as metabolic regulation and memory consolidation. Dysregulation in the circadian rhythm can negatively impact human health, resulting in cardiovascular and metabolic diseases, psychiatric disorders, and premature death. Emerging evidence points to a relationship between the dysregulation circadian rhythm and neurodegenerative diseases, suggesting that the alterations in circadian function might play crucial roles in the pathogenesis and progression of neurodegenerative diseases. Better understanding this association is of paramount importance to expand the knowledge on the pathophysiology of neurodegenerative diseases, as well as, to provide potential targets for the development of new interventions based on the dysregulation of circadian rhythm. Here we review the latest findings on dysregulation of circadian rhythm alterations in Parkinson's disease, Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, multiple sclerosis, spinocerebellar ataxia and multiple-system atrophy, focusing on research published in the last 3 years.

The impact of a western diet on gut microbiota and circadian rhythm: A comprehensive systematic review of in vivo preclinical evidence

AIMS

Here, we present a systematic review that compiles in vivo experimental data regarding the effect of the WD on the gut microbiota and its impact on the circadian rhythm. Additionally, we reviewed studies evaluating the combined effects of WD and circadian cycle disruption on gut microbiota and circadian cycle markers.

MATERIALS AND METHODS

The original studies indexed in PubMed/Medline, Scopus, and Web of Science databases were screened according to the PRISMA strategy.

KEY FINDINGS

Preclinical studies revealed that WD triggers circadian rhythmicity disruption, reduces the alpha-diversity of the microbiota and favors the growth of bacterial groups that are detrimental to intestinal homeostasis, such as Clostridaceae, Enterococcus, Parasutterella and Proteobacteria. When the WD is combined with circadian clock disruption, gut dysbiosis become more pronounced. Reduced cycling of Per3, Rev-erb and CLOCK in the intestine, which are related to dysregulation of lipid metabolism and potential metabolic disease, was observed.

SIGNIFICANCE

In conclusion, current evidence supports the potential of WD to trigger microbiota dysregulation, disrupt the biological clock, and increase susceptibility to metabolic disorders and potentially chronic diseases.

Chrononutrition in traditional European medicine-Ideal meal timing for cardiometabolic health promotion

Meal timing plays a crucial role for cardiometabolic health, given the circadian regulation of cardiometabolic function. However, to the best of our knowledge, no concept of meal timing exists in traditional European medicine (TEM). Therefore, in this narrative review, we aim to define the optimal time slot for energy intake and optimal energy distribution throughout the day in a context of TEM and explore further implications. By reviewing literature published between 2002 and 2022, we found that optimal timing for energy intake may be between 06:00 and 09:00, 12:00 and 14:00, and between 15:00 and 18:00, with high energy breakfast, medium energy lunch and low energy dinner and possibly further adjustments according to one's chronotype and genetics. Also, timing and distribution of energy intake may serve as a novel therapeutic strategy to optimize coction, a concept describing digestion and metabolism in TEM. Please cite this article as: Eberli NS, Colas L, Gimalac A. Chrononutrition in traditional European medicine-Ideal meal timing for cardiometabolic health promotion. J Integr Med. 2024; 22(2);115-125.

Circadian Disruption across Lifespan Impairs Glucose Homeostasis and Insulin Sensitivity in Adult Mice

Circadian rhythm disruption is associated with impaired glucose homeostasis and type 2 diabetes. For example, night shift work is associated with an increased risk of gestational diabetes. However, the effects of chronic circadian disruption since early life on adult metabolic health trajectory remain unknown. Here, using the "Short Day" (SD) mouse model, in which an 8 h/8 h light/dark (LD) cycle was used to disrupt mouse circadian rhythms across the lifespan, we investigated glucose homeostasis in adult mice. Adult SD mice were fully entrained into the 8 h/8 h LD cycle, and control mice were entrained into the 12 h/12 h LD cycle. Under a normal chow diet, female and male SD mice displayed a normal body weight trajectory. However, female but not male SD mice under a normal chow diet displayed glucose intolerance and insulin resistance, which are associated with impaired insulin signaling/AKT in the skeletal muscle and liver. Under high-fat diet (HFD) challenges, male but not female SD mice demonstrated increased body weight gain compared to controls. Both male and female SD mice developed glucose intolerance under HFD. Taken together, these results demonstrate that environmental disruption of circadian rhythms contributes to obesity in a sexually dimorphic manner but increases the risk of glucose intolerance and insulin resistance in both males and females.

Regulation of headache response and transcriptomic network by the trigeminal ganglion clock

OBJECTIVE

To characterize the circadian features of the trigeminal ganglion in a mouse model of headache.

BACKGROUND

Several headache disorders, such as migraine and cluster headache, are known to exhibit distinct circadian rhythms of attacks. The circadian basis for these rhythmic pain responses, however, remains poorly understood.

METHODS

We examined trigeminal ganglion ex vivo and single-cell cultures from Per2::LucSV reporter mice and performed immunohistochemistry. Circadian behavior and transcriptomics were investigated using a novel combination of trigeminovascular and circadian models: a nitroglycerin mouse headache model with mechanical thresholds measured every 6 h, and trigeminal ganglion RNA sequencing measured every 4 h for 24 h. Finally, we performed pharmacogenomic analysis of gene targets for migraine, cluster headache, and trigeminal neuralgia treatments as well as trigeminal ganglion neuropeptides; this information was cross-referenced with our cycling genes from RNA sequencing data to identify potential targets for chronotherapy.

RESULTS

The trigeminal ganglion demonstrates strong circadian rhythms in both ex vivo and single-cell cultures, with core circadian proteins found in both neuronal and non-neuronal cells. Using our novel behavioral model, we showed that nitroglycerin-treated mice display circadian rhythms of pain sensitivity which were abolished in arrhythmic Per1/2 double knockout mice. Furthermore, RNA-sequencing analysis of the trigeminal ganglion revealed 466 genes that displayed circadian oscillations in the control group, including core clock genes and clock-regulated pain neurotransmitters. In the nitroglycerin group, we observed a profound circadian reprogramming of gene expression, as 331 of circadian genes in the control group lost rhythm and another 584 genes gained rhythm. Finally, pharmacogenetics analysis identified 10 genes in our trigeminal ganglion circadian transcriptome that encode target proteins of current medications used to treat migraine, cluster headache, or trigeminal neuralgia.

CONCLUSION

Our study unveiled robust circadian rhythms in the trigeminal ganglion at the behavioral, transcriptomic, and pharmacogenetic levels. These results support a fundamental role of the clock in pain pathophysiology.

PLAIN LANGUAGE SUMMARY

Several headache diseases, such as migraine and cluster headache, have headaches that occur at the same time each day. We learned that the trigeminal ganglion, an important pain structure in several headache diseases, has a 24-hour cycle that might be related to this daily cycle of headaches. Our genetic analysis suggests that some medications may be more effective in treating migraine and cluster headache when taken at specific times of the day.

Various types of fasting diet and possible benefits in nonalcoholic fatty liver: Mechanism of actions and literature update

Non-alcoholic fatty liver disease (NAFLD) is one of the major causes of chronic liver injury, affecting around one-fourth of the general population across the world. Several important pathophysiological mechanisms underlying NAFLD include oxidative stress, inflammation, liver fibrosis, and apoptosis. Currently, therapeutic approaches are not ideal for managing NAFLD, thus new approaches and treatments are still needed. Over the last two decades, various fasting protocols have been explored to reduce body weight and improve metabolic disorders. In this review, we provide updated literature that supports fasting regimens for subjects with NAFLD and describes underlying mechanisms of action. We suggest that fasting regimens may modulate NAFLD via several mechanisms, including changes in gut microbiota, hepatic arginase, hepatic autophagy, inflammatory responses, liver functional enzymes and hepatic steatosis, fibroblast growth factors signaling, white adipose tissue browning, adipokines, circadian rhythms, lipid profiles, and body composition.

Intestinal microbial circadian rhythms drive sex differences in host immunity and metabolism

Circadian rhythms dynamically regulate sex differences in metabolism and immunity, and circadian disruption increases the risk of metabolic disorders. We investigated the role of sex-specific intestinal microbial circadian rhythms in host metabolism using germ-free and conventionalized mice and manipulation of dietary-derived fat, fiber, and microbiota-accessible carbohydrates. Our findings demonstrate that sex differences in circadian rhythms of genes involved in immunity and metabolism depend on oscillations in microbiota, microbial metabolic functions, and microbial metabolites. Further, we show that consuming an obesogenic, high-fat, low-fiber diet produced sex-specific changes in circadian rhythms in microbiota, metabolites, and host gene expression, which were linked to sex differences in the severity of metabolic dysfunction. Our results reveal that microbial circadian rhythms contribute to sex differences in immunity and metabolism and that dietary factors can entrain new circadian rhythms and modify the magnitude of sex differences in host-microbe circadian dynamics.

Circadian misalignment in obesity: The role for time-restricted feeding

BACKGROUND AND AIMS

The epidemic of obesity is associated with a substantial, complex and escalating burden of disease. Dietary and lifestyle interventions provide the mainstay of management; however, obesity is multifactorial and challenging to address clinically. Disrupted circadian behaviours, including late eating, are associated with obesity. Time-restricted feeding (TRF), the confinement of calorie intake to a temporal 'eating window', has received growing interest as a weight-loss intervention. Benefits are purported to arise from the fasting period and strengthened circadian metabolism. However, the current evidence-base for TRF is small-scale, limited, and there has been little evaluation of circadian schedule. This research aims to enable evidence-based conclusions regarding circadian-aligned TRF as a weight-loss intervention in obesity.

METHODS

A systematic three-tranche search strategy was conducted within PubMed. Included studies were critically evaluated. Search tranches scoped: interventional evidence for TRF; evidence linking meal timing, obesity and metabolic function; and evidence linking circadian function, obesity, and dysmetabolism. Results were summarised in a narrative analysis.

RESULTS

A total of 30 studies were included. From small-scale and short-term evidence, TRF was consistently associated with improved weight, glycaemic and anthropometric outcomes versus baseline or control. Good adherence and safety, and consistency of results between studies, were notable. Earlier ('circadian-aligned') eating was associated with greater diet-induced thermogenesis, and improved weight loss and glycaemic outcomes. Limited evidence suggested meaningful correlations between circadian clock function and obesity/metabolic risk.

CONCLUSIONS

Circadian-aligned TRF may present a promising intervention for weight loss and metabolic benefits in obese/overweight individuals.

Mitochondrial pyruvate metabolism and glutaminolysis toggle steady-state and emergency myelopoiesis

To define the metabolic requirements of hematopoiesis, we examined blood lineages in mice conditionally deficient in genes required for long-chain fatty acid oxidation (Cpt2), glutaminolysis (Gls), or mitochondrial pyruvate import (Mpc2). Genetic ablation of Cpt2 or Gls minimally impacted most blood lineages. In contrast, deletion of Mpc2 led to a sharp decline in mature myeloid cells and a slower reduction in T cells, whereas other hematopoietic lineages were unaffected. Yet MPC2-deficient monocytes and neutrophils rapidly recovered due to a transient and specific increase in myeloid progenitor proliferation. Competitive bone marrow chimera and stable isotope tracing experiments demonstrated that this proliferative burst was progenitor intrinsic and accompanied by a metabolic switch to glutaminolysis. Myeloid recovery after loss of MPC2 or cyclophosphamide treatment was delayed in the absence of GLS. Reciprocally, MPC2 was not required for myeloid recovery after cyclophosphamide treatment. Thus, mitochondrial pyruvate metabolism maintains myelopoiesis under steady-state conditions, while glutaminolysis in progenitors promotes emergency myelopoiesis.

Association between circadian clock gene expressions and meal timing in young and older adults

Ageing is associated with a decline in circadian clock systems, which correlates with the development of ageing-associated diseases. Chrononutrition is a field of chronobiology that examines the relationship between the timing of meal/nutrition and circadian clock systems. Although there is growing evidence regarding the role of chrononutrition in the prevention of lifestyle and ageing-related diseases, the optimal timing of meal intake to regulate the circadian clock in humans remains unknown. In this study, we investigated the relationship between clock gene expression and meal timing in young and older adults. In this cross-sectional study, we enrolled 51 healthy young men and 35 healthy older men (age, mean±standard deviation: 24 ± 4 and 70 ± 4 y, respectively). Under daily living conditions, beard follicle cells were collected at 4-h intervals over a 24-h period to evaluate clock gene expression. Participants were asked to record the timing of habitual sleep and wake-up, breakfast, lunch, and dinner. From these data, we calculated "From bedtime to breakfast time," "From wake up to first meal time," and "From dinner to bed time." NR1D1 and PER3 expressions in older adults at 06:00 h were significantly higher than those in young adults (P = 0.001). There were significant differences in the peak time for NR1D2 (P = 0.003) and PER3 (P = 0.049) expression between young and older adults. "From bedtime to breakfast time" was significantly longer in older adults than in young adults. In contrast, "From dinner to bed time" was significantly shorter in older adults than in young adults. Moreover, higher rhythmicity of NR1D1 correlated with longer "From bedtime to breakfast time" (r =  -0.470, P = 0.002) and shorter "From wake up to first meal time" in young adults (r = 0.302, P = 0.032). Higher rhythmicity of PER3 correlated with longer "From bedtime to breakfast time" in older adults (r =  -0.342, P = 0.045). These results suggest that the peak time of clock gene expression in older adults may be phase-advanced compared to that in young adults. In addition, a longer fasting duration from bedtime to breakfast in both young and older adults and earlier intake of meals after waking up in young adults may correlate with robust clock gene expression rhythms.

Circadian Variation in Human Milk Hormones and Macronutrients

There is an inadequate understanding of the daily variations in hormones and macronutrients in human milk (HM), and sample collection protocols vary considerably from study to study. To investigate changes in these milk components across 24 h, 22 lactating women collected small milk samples before and after each breastfeed or expression from each breast. Test weighing was used to determine the volume of HM consumed in each feed. The concentrations of leptin, adiponectin, insulin, fat, and glucose were measured, and the intakes were calculated. A linear mixed model was fitted to assess within-feed and circadian variation in HM feed volume and concentration, and intakes of several components. The average infant intake of HM was 879 g/24 h. Significantly higher pre-feed concentrations were found for adiponectin and glucose and lower post-feed concentrations were found for insulin and fat. Significant circadian rhythms were displayed for leptin, adiponectin, insulin, glucose (both concentration and intake), fat concentration, and milk volume. These findings demonstrate the necessity for setting up standardised and rigorous sampling procedures that consider both within-feed and circadian variations in HM components to gain a more precise understanding of the impacts of these components on infant health, growth and development.

Mediating effect of eating pattern on the relationship between television exposure and caries in children

Behavioral characteristics may also take part in the etiology of dental caries. Sedentary behavior, especially watching television, is associated with increased intake of foods high in fat or free sugar, which could influence the occurrence of dental caries. The aim of this study was to assess the mediating effect of eating pattern on the relationship between television exposure time and the presence of dental caries in children. A cross-sectional study was conducted with a representative sample of 580 parent-child dyads with children aged 7 to 8 years in 20 public schools in Pelotas, Brazil. Parents or legal guardians were interviewed and provided information on demographic/socioeconomic data, children's daily television exposure time, and answered the Biological Rhythms Interview for Assessment in Neuropsychiatry for Kids (BRIAN-K-eating pattern domain). Caries was evaluated through clinical examination. The mediating effect of eating pattern on the relationship between television exposure and presence of dental caries was estimated using the parametric g-formula. Prevalence of dental caries was 63%, and 22% of children watched TV 4 or more hours per day. Television exposure had no direct effect on the dental caries experience [odds ratio (OR): 1.05 (95% confidence interval (95%CI): 0.92-1.19)]. Nevertheless, difficulty maintaining regular eating pattern mediated the natural indirect effect of television exposure time (≥ 4 hours/day) on dental caries experience [OR: 1.07 (95%CI): 1.01-1.14)]. The results of this study confirm the indirect pathway between television viewing and dental caries and the role of disordered eating patterns in this association.

Best Time of Day for Strength and Endurance Training to Improve Health and Performance? A Systematic Review with Meta-analysis

BACKGROUND

Current recommendations for physical exercise include information about the frequency, intensity, type, and duration of exercise. However, to date, there are no recommendations on what time of day one should exercise. The aim was to perform a systematic review with meta-analysis to investigate if the time of day of exercise training in intervention studies influences the degree of improvements in physical performance or health-related outcomes.

METHODS

The databases EMBASE, PubMed, Cochrane Library, and SPORTDiscus were searched from inception to January 2023. Eligibility criteria were that the studies conducted structured endurance and/or strength training with a minimum of two exercise sessions per week for at least 2 weeks and compared exercise training between at least two different times of the day using a randomized crossover or parallel group design.

RESULTS

From 14,125 screened articles, 26 articles were included in the systematic review of which seven were also included in the meta-analyses. Both the qualitative synthesis and the quantitative synthesis (i.e., meta-analysis) provide little evidence for or against the hypothesis that training at a specific time of day leads to more improvements in performance-related or health-related outcomes compared to other times. There was some evidence that there is a benefit when training and testing occur at the same time of day, mainly for performance-related outcomes. Overall, the risk of bias in most studies was high.

CONCLUSIONS

The current state of research provides evidence neither for nor against a specific time of the day being more beneficial, but provides evidence for larger effects when there is congruency between training and testing times. This review provides recommendations to improve the design and execution of future studies on this topic.

REGISTRATION

PROSPERO (CRD42021246468).

Effects of Irregular Mealtimes on Social and Eating Jet Lags among Japanese College Students

College students' social and eating jet lags and chronotypes may be related to irregular eating habits. Therefore, we examined the relationship between social and eating jet lags, chronotypes, variability in first and last mealtimes, and non-eating duration, as well as the effects of snacking between dinner and bedtime on social and eating jet lags, chronotypes, and mealtime variation. A total of 1900 Japanese male college students were recruited in this study. Mean wake-up time, bedtime, sleeping time, first and last mealtimes, snacks between meals, non-eating duration, the midpoint of non-eating duration, social and eating jet lags, and chronotype were calculated. Standard deviations in first and last mealtimes, the midpoint of non-eating duration, and the coefficient of variation in non-eating duration were used to evaluate mealtime variations. Mealtime variations were significantly associated with social and eating jet lags, chronotype, the midpoint of non-eating duration, and the difference in first and last mealtime between school holidays and class days. Chronotype and the midpoint of non-eating duration were significantly delayed with increased snacking after dinner. Mealtime variations were significantly lower in those who avoided snacking than in those who did not. Thus, social and eating jet lags and chronotypes are associated with sleep habits and mealtime irregularities.

Turning Back the Clock: A Retrospective Single-Blind Study on Brain Age Change in Response to Nutraceuticals Supplementation vs. Lifestyle Modifications

BACKGROUND

There is a growing consensus that chronological age (CA) is not an accurate indicator of the aging process and that biological age (BA) instead is a better measure of an individual's risk of age-related outcomes and a more accurate predictor of mortality than actual CA. In this context, BA measures the "true" age, which is an integrated result of an individual's level of damage accumulation across all levels of biological organization, along with preserved resources. The BA is plastic and depends upon epigenetics. Brain state is an important factor contributing to health- and lifespan.

METHODS AND OBJECTIVE

Quantitative electroencephalography (qEEG)-derived brain BA (BBA) is a suitable and promising measure of brain aging. In the present study, we aimed to show that BBA can be decelerated or even reversed in humans (N = 89) by using customized programs of nutraceutical compounds or lifestyle changes (mean duration = 13 months).

RESULTS

We observed that BBA was younger than CA in both groups at the end of the intervention. Furthermore, the BBA of the participants in the nutraceuticals group was 2.83 years younger at the endpoint of the intervention compared with their BBA score at the beginning of the intervention, while the BBA of the participants in the lifestyle group was only 0.02 years younger at the end of the intervention. These results were accompanied by improvements in mental-physical health comorbidities in both groups. The pre-intervention BBA score and the sex of the participants were considered confounding factors and analyzed separately.

CONCLUSIONS

Overall, the obtained results support the feasibility of the goal of this study and also provide the first robust evidence that halting and reversal of brain aging are possible in humans within a reasonable (practical) timeframe of approximately one year.

Translation, adaptation and validation of the Chrononutrition Profile - Questionnaire (CP-Q) in Brazilian Portuguese

Chrononutrition is a science that studies the relationship between mealtimes and sleep/wake habits. However, these behaviors are not evaluated by a single questionnaire. Therefore, this study aimed to translate and culturally adapt the Chrononutrition Profile - Questionnaire (CP-Q) into Portuguese and validate the Brazilian version. The translation and cultural adaptation process consisted of: translation; synthesis of translations; backtranslation; expert committee and pre-test. The validation was performed with 635 participants (32.4 ± 11.2 years) who answered the CPQ-Brazil and Pittsburgh Sleep Quality Index (PSQI); Munich Chronotype Questionnaire (MCTQ); Night Eating questionnaire; Quality of life and health index (SF-36) and 24 h-recall. The participants were mostly female, single, from the northeastern region, a eutrophic profile, and average quality of life score of 55.8 ± 17.9. Moderate to strong correlations were observed in the sleep/wake schedules between CPQ-Brazil, PSQI and MCTQ, both for work/study days and free days. The correlations between largest meal, skipping breakfast, eating window, nocturnal latency, and last eating event with the same variables in the 24 h-recall showed moderate to strong positive correlations. The translation, adaptation, validation and reproducibility of the CP-Q generates a valid and reliable questionnaire to assess the sleep/wake and eating habits in the Brazilian population.

Circadian disruption: from mouse models to molecular mechanisms and cancer therapeutic targets

The circadian clock is a timekeeping system for numerous biological rhythms that contribute to the regulation of numerous homeostatic processes in humans. Disruption of circadian rhythms influences physiology and behavior and is associated with adverse health outcomes, especially cancer. However, the underlying molecular mechanisms of circadian disruption-associated cancer initiation and development remain unclear. It is essential to construct good circadian disruption models to uncover and validate the detailed molecular clock framework of circadian disruption in cancer development and progression. Mouse models are the most widely used in circadian studies due to their relatively small size, fast reproduction cycle, easy genome manipulation, and economic practicality. Here, we reviewed the current mouse models of circadian disruption, including suprachiasmatic nuclei destruction, genetic engineering, light disruption, sleep deprivation, and other lifestyle factors in our understanding of the crosstalk between circadian rhythms and oncogenic signaling, as well as the molecular mechanisms of circadian disruption that promotes cancer growth. We focused on the discoveries made with the nocturnal mouse, diurnal human being, and cell culture and provided several circadian rhythm-based cancer therapeutic strategies.

Effects of Morning Vs. Evening exercise on appetite, energy intake, performance and metabolism, in lean males and females

Exercise is an important component of a weight management strategy. However, little is known about whether circadian variations in physiological and behavioural processes can influence the appetite and energy balance responses to exercise performed at different times of the day. This study compared the effects of morning and evening exercise on appetite, post-exercise energy intake, and voluntary performance. In randomised, counterbalanced order, 16 healthy males and females (n = 8 each) completed two trials, performing morning exercise at 10:30 (AMEx) or evening exercise at 18:30 (PMEx). Exercise consisted of 30 min steady-state cycling (60% V˙ O_2peak), and a 15-min performance test. A standardised meal (543 ± 86 kcal) was consumed 2-h before exercise and ad-libitum energy intake was assessed 15 min after exercise, with subjective appetite measured throughout. Absolute ad-libitum energy intake was 152 ± 126 kcal greater during PMEx (P < 0.001), but there was no differences in subjective appetite between trials immediately pre-exercise, or immediately before the post-exercise meal (P ≥ 0.060). Resting energy expenditure (P < 0.01) and carbohydrate oxidation (P < 0.05) were greater during AMEx, but there were no differences in substrate oxidation or energy expenditure during exercise (P ≥ 0.155). Exercise performance was not different between trials (P = 0.628). In conclusion, acute morning and evening exercise prompt similar appetite responses, but post-exercise ad-libitum energy intake is greater following evening exercise. These findings demonstrate discordant responses between subjective appetite and ad-libitum energy intake but suggest that exercise might offset circadian variations in appetite. Longer-term studies are required to determine how exercise timing affects adherence and weight management outcomes to exercise interventions. TRIAL REGISTRATION: NCT04742530, February 8, 2021.

Down-regulation of hepatic CLOCK by PPARα is involved in inhibition of NAFLD

This work aimed to investigate the role of nuclear factor peroxisome proliferator-activated receptor α (PPARα) in modification of circadian clock and their relevance to development of nonalcoholic fatty liver disease (NAFLD). Both male wild-type (WT) and Pparα-null (KO) mice treated with high-fat diet (HFD) were used to explore the effect of PPARα and lipid diet on the circadian rhythm. WT, KO, and PPARα-humanized (hPPARα) mice were treated with PPARα agonist fenofibrate to reveal the hPPARα dependence of circadian locomotor output cycles kaput (CLOCK) down-regulation. The mouse model and hepatocyte experiments were designed to verify the action of PPARα in down-regulating CLOCK and lipid accumulation in vivo and in vitro. Strongest NAFLD developed in mice fed 45%HFD, and it was inhibited in WT mice. The activity rhythm of WT mice was found to be different from that of the KO mice on normal diet and HFD. The core circadian factor CLOCK was down-regulated by HFD in both WT and KO mice in the liver, not in the hypothalamus. More interestingly, hepatic CLOCK was down-regulated by basal PPARα and activated PPARα in dose dependence of fenofibrate. Accordingly, CLOCK down-regulation dependent of PPARα activity was involved in inhibition of lipid metabolism in hepatocytes. Down-regulation of hepatic CLOCK by basal PPARα contributes to tolerance against development of NAFLD. Inhibition of CLOCK by activated PPARα is involved in inhibition of NAFLD by PPARα agonists. KEY MESSAGES: • PPARα inhibited NAFLD development induced by HFD. • PPARα mediated modifications of circadian rhythm and the hepatic circadian factor CLOCK in NAFLD models. • Down-regulation of hepatic CLOCK by basal PPARα contributed to tolerance against development of NAFLD. • Inhibition of CLOCK by activated PPARα was involved in therapeutic actions against fatty liver diseases by PPARα agonists.

Effect of Circadian Rhythm Disturbance on the Human Musculoskeletal System and the Importance of Nutritional Strategies

The circadian system in the human body responds to daily environmental changes to optimise behaviour according to the biological clock and also influences various physiological processes. The suprachiasmatic nuclei are located in the anterior hypothalamus of the brain, and they synchronise to the 24 h light/dark cycle. Human physiological functions are highly dependent on the regulation of the internal circadian clock. Skeletal muscles comprise the largest collection of peripheral clocks in the human body. Both central and peripheral clocks regulate the interaction between the musculoskeletal system and energy metabolism. The skeletal muscle circadian clock plays a vital role in lipid and glucose metabolism. The pathogenesis of osteoporosis is related to an alteration in the circadian rhythm. In the present review, we discuss the disturbance of the circadian rhythm and its resultant effect on the musculoskeletal system. We also discuss the nutritional strategies that are potentially effective in maintaining the system's homeostasis. Active collaborations between nutritionists and physiologists in the field of chronobiological and chrononutrition will further clarify these interactions. This review may be necessary for successful interventions in reducing morbidity and mortality resulting from musculoskeletal disturbances.

Chrono-Nutrition: Circadian Rhythm and Personalized Nutrition

The human circadian system has a period of approximately 24 h and studies on the consequences of "chornodisruption" have greatly expanded. Lifestyle and environmental factors of modern societies (i.e., artificial lighting, jetlag, shift work, and around-the-clock access to energy-dense food) can induce disruptions of the circadian system and thereby adversely affect individual health. Growing evidence demonstrates a complex reciprocal relationship between metabolism and the circadian system, in which perturbations in one system affect the other one. From a nutritional genomics perspective, genetic variants in clock genes can both influence metabolic health and modify the individual response to diet. Moreover, an interplay between the circadian rhythm, gut microbiome, and epigenome has been demonstrated, with the diet in turn able to modulate this complex link suggesting a remarkable plasticity of the underlying mechanisms. In this view, the study of the impact of the timing of eating by matching elements from nutritional research with chrono-biology, that is, chrono-nutrition, could have significant implications for personalized nutrition in terms of reducing the prevalence and burden of chronic diseases. This review provides an overview of the current evidence on the interactions between the circadian system and nutrition, highlighting how this link could in turn influence the epigenome and microbiome. In addition, possible nutritional strategies to manage circadian-aligned feeding are suggested.

Time-related meal patterns and breakfast quality in a sample of Iranian adults

BACKGROUND

Some evidence shows that meal timing is associated with diet quality. We aimed to investigate the relationship between meal timing and breakfast quality in a sample of Iranian adults.

METHODS

This cross-sectional study was conducted on 850 men and women living in Tehran, Iran. Dietary data was recorded by three non-consecutive 24-h dietary recalls. The Breakfast Quality Index (BQI) was calculated. Time-related meal patterns included the interval between the first and last meal (eating and fasting window), frequency of meals, length of sleep, and time of first and last eating occasion. The multiple linear regression analysis was used to identify the relationships between time-related meal patterns and BQI.

RESULTS

The mean (95% CI) of BQI was 4.52 (4.45-4.65) and the maximum was 8. Bread, cheese, vegetables, fruits, energy, and carbohydrate intake showed positive associations with BQI scores. Longer fasting time showed a positive association with fruits (β (CI 95%)) (0.11 (0.0003-0.005), and vegetable consumption (0.12 (0.009-0.07)) and BQI score (0.39 (0.001-0.06)). Time of first eating occasions indicated a negative association with protein and fat intake and BQI score. Time of last eating occasions showed a positive association with vegetables consumption and BQI score. The longer length of sleep was associated with a higher BQI score. The frequency of meals was significantly and positively related to energy and macronutrients intake and BQI.

CONCLUSION

Earlier first and last meal, longer sleep length, longer fasting window, and a greater meal frequency were associated with a better breakfast quality.

Impacts of vitamin A deficiency on biological rhythms: Insights from the literature

Vitamin A is essential for brain function, in addition to its important roles in vision, immunity, and reproduction. Previous studies have shown that retinoic acid (RA), the bioactive form of vitamin A, is involved in the regulation of various intracellular responses related to biological rhythms. RA is reported to affect the circadian rhythm by binding to RA receptors, such as receptors in the circadian feedback loops in the mammalian suprachiasmatic nucleus. However, evidence of the impacts of vitamin A deficiency (VAD) on biological rhythms is limited, and most of the related studies were conducted on animals. In this review, we described the physiological functions of biological rhythms and physiological pathways/molecular mechanisms regulating the biological rhythms. We then discussed the current understanding of the associations of VAD with biological rhythm disorders/diseases (sleep disorders, impairments in learning/memory, emotional disorders, and other immune or metabolism diseases) and summarized the currently proposed mechanisms (mainly by retinoid nuclear receptors and related proteins) for the associations. This review may help recognize the role of VAD in biological rhythm disorders and stimulate clinical or epidemiological studies to confirm the findings of related animal studies.

Circadian Rhythm Disruption as a Contributor to Racial Disparities in Prostate Cancer

In the United States, African American (AA) men have a 2.4 times higher mortality rate due to prostate cancer than White men. The multifactorial causes of the racial disparities in prostate cancer involve various social determinants of health, socioeconomic status, and access to healthcare. However, emerging evidence also suggests that circadian rhythm disruption (CRD) contributes to prostate cancer, and AA men may be more susceptible to developing CRDs. Circadian rhythms play a significant role in metabolism, hormone secretion, and sleep/wake cycles. Disruption in these circadian rhythms can be caused by airplane travel/jetlag, night shift work, exposure to light, and neighborhood noise levels, which can contribute to sleep disorders and chronic conditions such as obesity, diabetes, cardiovascular disease, and depression. The drivers of the racial disparities in CRD include night shift work, racial discrimination, elevated stress, and residing in poor neighborhoods characterized by high noise pollution. Given the increased vulnerability of AA men to CRDs, and the role that CRDs play in prostate cancer, elucidating the clock-related prostate cancer pathways and their behavior and environmental covariates may be critical to better understanding and reducing the racial disparities in prostate cancer.

Practice recommendations for the role of physiotherapy in the management of sleep disorders: the 2022 Brazilian Sleep Association Guidelines

This clinical guideline supported by the Brazilian Sleep Association comprises a brief history of the development of Brazilian sleep physiotherapy, outlines the role of the physiotherapist as part of a sleep health team, and describes the clinical guidelines in respect of the management of some sleep disorders by the physiotherapist (including sleep breathing disorders, i.e., obstructive sleep apnea, central sleep apnea, upper airway resistance syndrome, hypoventilation syndromes and overlap syndrome, and pediatric sleep breathing disorders; sleep bruxism; circadian rhythms disturbances; insomnia; and Willis-Ekbom disease/periodic limb movement disorder. This clinical practice guideline reflects the state of the art at the time of publication and will be reviewed and updated as new information becomes available.

The pancreatic clock is a key determinant of pancreatic fibrosis progression and exocrine dysfunction

Chronic pancreatitis (CP) is characterized by progressive fibrosis and exocrine dysregulation, which have long been considered irreversible. As a peripheral oscillator, the pancreas harbors autonomous and self-sustained timekeeping systems in both its endocrine and exocrine compartments, although the role of the latter remains poorly understood. By using different models of CP established in mice with dysfunctional pancreatic clocks, we found that the local clock played an important role in CP pathology, and genetic or external disruption of the pancreatic clock exacerbated fibrogenesis and exocrine insufficiency. Mechanistically, an impaired retinoic acid receptor-related orphan receptor A (Rora)/nuclear receptor subfamily 1, group D, member 1 (Nr1d1)/aryl hydrocarbon receptor nuclear translocator-like (Arntl or Bmal1) loop, called the circadian stabilizing loop, resulted in the deficiency of pancreatic Bmal1, which was responsible for controlling the fibrogenic properties of pancreatic stellate cells (PSCs) and for rewiring the function of acinar cells in a clock-TGF signaling-IL-11/IL-11RA axis-dependent manner. During PSC activation, the antagonistic interaction between Nr1d1 and Rora was unbalanced in response to the loss of cytoplasmic retinoid-containing lipid droplets. Patients with CP also exhibited reduced production of endogenous melatonin. Enhancing the clock through pharmacological restoration of the circadian stabilizing loop using a combination of melatonin and the Rora agonist SR1078 attenuated intrapancreatic pathological changes in mouse models of CP. Collectively, this study identified a protective role of the pancreatic clock against pancreatic fibrosis and exocrine dysfunction. Pancreatic clock-targeted therapy may represent a potential strategy to treat CP.

Relationship among chrononutrition, sleep, and glycemic control in women with gestational diabetes mellitus: a randomized controlled trial

BACKGROUND

Gestational diabetes mellitus is associated with an increased risk of maternal, fetal, and neonatal morbidities. Chronobiological disorders have recently been identified as risk factors for those morbidities. The disorders include chrononutritional disorders related to meal frequency and content according to the sleep-wake cycle, sleep disorders related to sleep quality, and chrono-obesity disorders, such as abnormal weight gain because of sleep deprivation and time of eating.

OBJECTIVE

This study aimed to assess whether a chrononutritional and sleep hygiene intervention can improve maternal glycemic control and reduce the proportion of large-for-gestational-age newborns among women with gestational diabetes mellitus.

STUDY DESIGN

This randomized controlled trial included 103 women with gestational diabetes mellitus who were carrying a singleton fetus and assigned to either the intervention group (n=33) or the control group (n=70). The intervention group was assigned to a chrononutrition and sleep hygiene program, in addition to the usual care for gestational diabetes mellitus, from the time of diabetes mellitus diagnosis to birth, whereas the control group received the usual gestational diabetes mellitus care.

RESULTS

The chrononutritional and sleep hygiene intervention significantly reduced the proportion of women with suboptimal glycemic control (<80% of the plasma glucose values at target), after adjustment for maternal age, prepregnancy body mass index, gravidity, history of gestational diabetes mellitus, and large for gestational age (relative risk, 0.28; 95% confidence interval, 0.18-0.81). The effect of the intervention on balancing maternal glycemic control was mainly because of the decreased carbohydrate intake in the evening interval of the day (relative risk, 0.8; 95% confidence interval, 0.64-0.99). However, the intervention had no effect on the proportion of large-for-gestational-age newborns.

CONCLUSION

The chrononutritional and sleep hygiene intervention can improve maternal glycemic control.

The Impact of Dietary Factors on the Sleep of Athletically Trained Populations: A Systematic Review

Many athletic populations report poor sleep, especially during intensive training and competition periods. Recently, diet has been shown to significantly affect sleep in general populations; however, little is known about the effect diet has on the sleep of athletically trained populations. With sleep critical for optimal recovery and sports performance, this systematic review aimed to evaluate the evidence demonstrating that dietary factors influence the sleep of athletically trained populations. Four electronic databases were searched from inception to May 2022, with primary research articles included if they contained a dietary factor(s), an outcome measure of sleep or sleepiness, and participants could be identified as ‘athletically trained’. Thirty-five studies were included, with 21 studies assessed as positive quality, 13 as neutral, and one as negative. Sleep or sleepiness was measured objectively in 46% of studies (n = 16). The review showed that evening (≥5 p.m.) caffeine intakes >2 mg·kg−1 body mass decreased sleep duration and sleep efficiency, and increased sleep latency and wake after sleep onset. Evening consumption of high glycaemic index carbohydrates and protein high in tryptophan may reduce sleep latency. Although promising, more research is required before the impact of probiotics, cherry juice, and beetroot juice on the sleep of athletes can be resolved. Athletic populations experiencing sleep difficulties should be screened for caffeine use and trial dietary strategies (e.g., evening consumption of high GI carbohydrates) to improve sleep.

Is There a Utility of Chrono-Specific Diets in Improving Cardiometabolic Health?

Modern lifestyle is generally associated with the consumption of three main meals per day, one of which is typically in the evening or at night. It is also well established that consumption of meals in the later part of the day, notably in the evenings, is associated with circadian desynchrony, which in turn increases the risk of non-communicable diseases, particularly cardiometabolic diseases. While it is not feasible to avoid food consumption during the evenings altogether, there is an opportunity to provide chrono-specific, diet-based solutions to mitigate some of these risks. To date, there has been substantial progress in the understanding of chrononutrition, with evidence derived mainly from in vitro and in vivo animal studies. Some of these approaches include the manipulation of the quality and quantity of certain nutrients to be consumed at specific times of the day, as well as incorporating certain dietary components (macronutrients, micronutrients, or non-nutrient bioactives, including polyphenols) with the ability to modulate circadian rhythmicity. However, robust human studies are generally lacking. In this review, the study has consolidated and critically appraised the current evidence base, with an aim to translate these findings to improve cardiometabolic health and provides recommendations to move this field forward.

Efficacy of Kushen decoction on high-fat-diet-induced hyperlipidemia in rats

OBJECTIVE

To investigate the efficacy and underlying mechanisms of action of Kushen decoction on high-fat-diet-induced hyperlipidemia in rats using RNA-seq technology.

METHODS

The efficacy of a Kushen decoction, at a concentration of 1 mL/g of crude medicine prepared according to the method commonly used in clinical practice, was investigated on 24 specific pathogen-free male Sprague-Dawley rats. Liver tissues were compared using RNA-Seq technology. The differentially expressed genes were further investigated by real-time fluorescent quantitative polymerase chain reaction (qPCR and Western blot (WB).

RESULTS

Serum triglycerides (TG), liver low-density lipoprotein cholesterol (LDL-C), body weight, body length, and Lee's index were significantly increased in the untreated hyperlipidemia-induced group (model) compared with the control group, whereas liver high-density lipoprotein cholesterol (HDL-C) was significantly decreased. Serum TG, liver LDL-C, bodyweight, and Lee's index were decreased in the high-dose Kushen decoction group (HDKS) compared with the model group, whereas liver HDL-C was significantly increased. Similarly, liver TG tended to decline in the HDKS group. Comparison of the gene expression profiles in the livers from different groups indicated that the Kushen decoction significantly affected metabolic pathways, PPAR signalling pathway, and circadian rhythm ( ≤ 0.05), with the genes ARNTL, PER3, and CLOCK being differentially expressed. qPCR and WB analysis confirmed the differential expression of the genes discovered by transcriptomics analysis.

CONCLUSION

The Kushen decoction may achieve a lipid-lowering effect on hyperlipidemic rats by regulating metabolic pathways and the circadian rhythm pathway and in particular, their related genes ARNTL, PER3, and CLOCK.

Circadian rhythm of lipid metabolism

Lipids comprise a diverse group of metabolites that are indispensable as energy storage molecules, cellular membrane components and mediators of inter- and intra-cellular signaling processes. Lipid homeostasis plays a crucial role in maintaining metabolic health in mammals including human beings. A growing body of evidence suggests that the circadian clock system ensures temporal orchestration of lipid homeostasis, and that perturbation of such diurnal regulation leads to the development of metabolic disorders comprising obesity and type 2 diabetes. In view of the emerging role of circadian regulation in maintaining lipid homeostasis, in this review, we summarize the current knowledge on lipid metabolic pathways controlled by the mammalian circadian system. Furthermore, we review the emerging connection between the development of human metabolic diseases and changes in lipid metabolites that belong to major classes of lipids. Finally, we highlight the mechanisms underlying circadian organization of lipid metabolic rhythms upon the physiological situation, and the consequences of circadian clock dysfunction for dysregulation of lipid metabolism.

Role of Chrononutrition in the Antihypertensive Effects of Natural Bioactive Compounds

Hypertension (HTN) is one of the main cardiovascular risk factors and is considered a major public health problem. Numerous approaches have been developed to lower blood pressure (BP) in hypertensive patients, most of them involving pharmacological treatments. Within this context, natural bioactive compounds have emerged as a promising alternative to drugs in HTN prevention. This work reviews not only the mechanisms of BP regulation by these antihypertensive compounds, but also their efficacy depending on consumption time. Although a plethora of studies has investigated food-derived compounds, such as phenolic compounds or peptides and their impact on BP, only a few addressed the relevance of time consumption. However, it is known that BP and its main regulatory mechanisms show a 24-h oscillation. Moreover, evidence shows that phenolic compounds can interact with clock genes, which regulate the biological rhythm followed by many physiological processes. Therefore, further research might be carried out to completely elucidate the interactions along the time–nutrition–hypertension axis within the framework of chrononutrition.

Circadian and Immunity Cycle Talk in Cancer Destination: From Biological Aspects to In Silico Analysis

Simple Summary

The circadian cycle is a natural cycle of the body repeated every 24 h, based on a day and night rhythm, and it affects many body processes. The present article reviews the importance and role of the circadian cycle in cancer and its association with the immune system and immunotherapy drugs at the cellular and molecular levels. It also examines the genes and cellular pathways involved in both circadian and immune systems. It offers possible computational solutions to increase the effectiveness of cancer treatment concerning the circadian cycle.

Abstract

Cancer is the leading cause of death and a major problem to increasing life expectancy worldwide. In recent years, various approaches such as surgery, chemotherapy, radiation, targeted therapies, and the newest pillar, immunotherapy, have been developed to treat cancer. Among key factors impacting the effectiveness of treatment, the administration of drugs based on the circadian rhythm in a person and within individuals can significantly elevate drug efficacy, reduce adverse effects, and prevent drug resistance. Circadian clocks also affect various physiological processes such as the sleep cycle, body temperature cycle, digestive and cardiovascular processes, and endocrine and immune systems. In recent years, to achieve precision patterns for drug administration using computational methods, the interaction of the effects of drugs and their cellular pathways has been considered more seriously. Integrated data-derived pathological images and genomics, transcriptomics, and proteomics analyses have provided an understanding of the molecular basis of cancer and dramatically revealed interactions between circadian and immunity cycles. Here, we describe crosstalk between the circadian cycle signaling pathway and immunity cycle in cancer and discuss how tumor microenvironment affects the influence on treatment process based on individuals’ genetic differences. Moreover, we highlight recent advances in computational modeling that pave the way for personalized immune chronotherapy.

Circadian rhythms and cancers: the intrinsic links and therapeutic potentials

The circadian rhythm is an evolutionarily conserved time-keeping system that comprises a wide variety of processes including sleep-wake cycles, eating-fasting cycles, and activity-rest cycles, coordinating the behavior and physiology of all organs for whole-body homeostasis. Acute disruption of circadian rhythm may lead to transient discomfort, whereas long-term irregular circadian rhythm will result in the dysfunction of the organism, therefore increasing the risks of numerous diseases especially cancers. Indeed, both epidemiological and experimental evidence has demonstrated the intrinsic link between dysregulated circadian rhythm and cancer. Accordingly, a rapidly increasing understanding of the molecular mechanisms of circadian rhythms is opening new options for cancer therapy, possibly by modulating the circadian clock. In this review, we first describe the general regulators of circadian rhythms and their functions on cancer. In addition, we provide insights into the mechanisms underlying how several types of disruption of the circadian rhythm (including sleep-wake, eating-fasting, and activity-rest) can drive cancer progression, which may expand our understanding of cancer development from the clock perspective. Moreover, we also summarize the potential applications of modulating circadian rhythms for cancer treatment, which may provide an optional therapeutic strategy for cancer patients.

Polycystic Ovary Syndrome: An Evolutionary Adaptation to Lifestyle and the Environment

Polycystic ovary syndrome (PCOS) is increasingly recognized as a complex metabolic disorder that manifests in genetically susceptible women following a range of negative exposures to nutritional and environmental factors related to contemporary lifestyle. The hypothesis that PCOS phenotypes are derived from a mismatch between ancient genetic survival mechanisms and modern lifestyle practices is supported by a diversity of research findings. The proposed evolutionary model of the pathogenesis of PCOS incorporates evidence related to evolutionary theory, genetic studies, in utero developmental epigenetic programming, transgenerational inheritance, metabolic features including insulin resistance, obesity and the apparent paradox of lean phenotypes, reproductive effects and subfertility, the impact of the microbiome and dysbiosis, endocrine-disrupting chemical exposure, and the influence of lifestyle factors such as poor-quality diet and physical inactivity. Based on these premises, the diverse lines of research are synthesized into a composite evolutionary model of the pathogenesis of PCOS. It is hoped that this model will assist clinicians and patients to understand the importance of lifestyle interventions in the prevention and management of PCOS and provide a conceptual framework for future research. It is appreciated that this theory represents a synthesis of the current evidence and that it is expected to evolve and change over time.

Face Validity of Observed Meal Patterns Reported with 7-Day Diet Diaries in a Large Population-Based Cohort Using Diurnal Variation in Concentration Biomarkers of Dietary Intake

In a cross-sectional analysis of a population-based cohort (United Kingdom, N = 21,318, 1993-1998), we studied how associations between meal patterns and non-fasting triglyceride and glucose concentrations were influenced by the hour of day at which the blood sample was collected to ascertain face validity of reported meal patterns, as well as the influence of reporting bias (assessed using formula of energy expenditure) on this association. Meal size (i.e., reported energy content), mealtime and meal frequency were reported using pre-structured 7-day diet diaries. In ANCOVA, sex-specific means of biomarker concentrations were calculated by hour of blood sample collection for quartiles of reported energy intake at breakfast, lunch and dinner (meal size). Significant interactions were observed between breakfast size, sampling time and triglyceride concentrations and between lunch size, sampling time and triglyceride, as well as glucose concentrations. Those skipping breakfast had the lowest triglyceride concentrations in the morning and those skipping lunch had the lowest triglyceride and glucose concentrations in the afternoon, especially among acceptable energy reporters. Eating and drinking occasion frequency was weakly associated with glucose concentrations in women and positively associated with triglyceride concentrations in both sexes; stronger associations were observed for larger vs. smaller meals and among acceptable energy reporters. Associations between meal patterns and concentration biomarkers can be observed when accounting for diurnal variation and underreporting. These findings support the use of 7-day diet diaries for studying associations between meal patterns and health.

The relationship between diet and sleep in 2-y-old children: Results from Growing Up in New Zealand

OBJECTIVES

This study aimed to examine the relationship between dietary practices and sleep in young children.

METHODS

In this study, 2-y-old children (n = 6327) and their mothers were enrolled at birth and during pregnancy, respectively. The study obtained maternal demographic, health, and lifestyle data during late pregnancy. Parents reported the 2-y-old child's dietary practices on a food frequency questionnaire, as well as sleep duration and night-waking frequency. Measures of dietary intake quantified servings per day for each food group (grouped as low/moderate/high intake). Sleep measures were as inadequate sleep when <11 h sleep in a 24-h period and increased night waking when waking ≥2 times per night. Multivariable logistic regression analyses examined associations between toddler diet and sleep, which were described using adjusted odds ratios (ORs) and 95% confidence intervals.

RESULTS

In this study, 2-y-old children (n = 6288) slept for a mean of 12.3 hours (standard deviation: ±1.5 hours) over a 24-h period, with 734 children (12%) getting <11 h of sleep in 24 h. Increased night waking occurred in 1063 children (17%). Compared with low intake, high soft drink/snack/fast food intake was associated with inadequate sleep (OR: 1.37) and increased night waking (OR: 1.34). High milk/cheese/yoghurt intake (OR: 1.55) was associated with increased odds of night waking, but moderate (OR: 0.81) or high (OR: 0.78) vegetable intake was associated with decreased odds of night waking. Exposure to screens (OR: 1.28) and heavy maternal cigarette smoking (OR: 2.20) were also associated with inadequate sleep and increased night waking, respectively.

CONCLUSIONS

At age 2 y, higher consumption of soft drinks/snacks/fast foods is associated with shorter, more disrupted sleep. Conversely, higher vegetable consumption is associated with less disrupted sleep. Dietary modifications may improve toddlers' sleep.

Relationship between physical activity, objective sleep parameters, and circadian rhythm in patients with head and neck cancer receiving chemoradiotherapy: A longitudinal study

OBJECTIVES

This study was developed to assess the relationship between physical activity, sleep and circadian rhythm using accelerometer and urine melatonin levels in patients with head and neck cancer (HNC). Also, this study evaluated the changes in physical activity, sleep, and circadian rhythm during the seven-week course of chemoradiotherapy.

METHODS

This longitudinal study recruited 27 participants diagnosed with HNC who were planning to undergo chemoradiotherapy. Accelerometers worn for 3 days during the 1st, 3rd, and 7th weeks of chemoradiotherapy were used to assess physical activity levels (step count and metabolic equivalents [METs]) and sleep quality (total sleep time [TST], sleep onset latency [SOL], and sleep efficiency [SE]). Urine melatonin analysis was conducted using the morning void urine sample on 1st, 3rd, and 7th weeks. The change in variables during the seven weeks and the correlation between them were analyzed.

RESULTS

During the seven weeks, trends of reduction in variables of physical activity, sleep and circadian rhythm were observed with significant decrease in step count, TST and melatonin levels. SE was found to have strong negative correlation with physical activity. TST was found to have moderate correlation with SE and step count. The variables of physical activity also showed moderate correlation among them.

CONCLUSION

This study concludes that higher physical activity is associated with poor SE due to increased night-time activity. There was a significant reduction in physical activity and sleep observed during seven weeks with moderate association between them. The significant circadian rhythm deregulation however showed poor association with the other variables.Level of Evidence: 2b.

Nutrigenetics and nutrigenomics-A personalized approach to nutrition

The prevalence of non-communicable diseases has been on an upward trajectory for some time and this puts an enormous burden on the healthcare expenditure. Lifestyle modifications including dietary interventions hold an immense promise to manage and prevent these diseases. Recent advances in genomic research provide evidence that focussing these efforts on individual variations in abilities to metabolize nutrients (nutrigenetics) and exploring the role of dietary compounds on gene expression (nutrigenomics and nutri-epigenomics) can lead to more meaningful personalized dietary strategies to promote optimal health. This chapter aims to provide examples on these gene-diet interactions at multiple levels to support the need of embedding targeted dietary interventions as a way forward to prevent, avoid and manage diseases.