Fasting as an intervention to alter the impact of simulated night-shift work on glucose metabolism in healthy adults: a cluster randomised controlled trial.

AIMS/HYPOTHESIS: Night-shift work causes circadian misalignment and impairs glucose metabolism. We hypothesise that food intake during night shifts may contribute to this phenomenon. METHODS: This open-label, multi-arm, single-site, parallel-group controlled trial involved a 6 day stay at the University of South Australia's sleep laboratory (Adelaide, SA, Australia). Healthy, non-shift-working adults without obesity (N=55; age 24.5 ± 4.8 years; BMI 24.8 ± 2.8 kg/m2) were assigned to the next available run date and cluster randomised (1:1:1) to fasting-at-night (N=20), snack-at-night (N=17), or meal-at-night (N=18) conditions. One participant withdrew from each group, prior to starting the study. Due to study design, neither participants nor people collecting their measurements could be blinded. Statistical and laboratory staff were concealed to study allocation. Participants were fed at calculated energy balance, with the macronutrient composition of meals being similar across conditions. The primary outcomes were a linear mixed-effects model of glucose, insulin and NEFA AUC in response to a 75 g OGTT that was conducted prior to and after 4 consecutive nights of shift work plus 1 night of recovery sleep. Insulin sensitivity, insulinogenic and disposition indexes were also calculated. RESULTS: Night-shift work impaired insulin sensitivity, as measured by insulin AUC (p=0.035) and the insulin sensitivity index (p=0.016) across all conditions. Insulin secretion, as measured by the insulinogenic index, was increased in the fasting-at-night condition only (p=0.030), resulting in a day×condition interaction in glucose AUC (p<0.001) such that glucose tolerance was impaired in the meal-at night (+2.00 [95% CI 1.45, 2.56], p<0.001) and snack at-night (+0.96 [0.36, 1.56], p=0.022) conditions vs the fasting-at-night (+0.34 [-0.21, 0.89]) condition. A day×condition interaction was also observed in NEFA AUC (p<0.001), being higher in the meal-at-night (+0.07 [0.03, 0.10]. p=0.001) and snack-at-night (0.01 [-0.03, 0.05], p=0.045) conditions vs the fasting-at-night condition (-0.02 [-0.06, 0.01]). No adverse events occurred. CONCLUSIONS/INTERPRETATION: The timing of food intake has a critical effect on glucose metabolism during simulated night-shift work, which was readily amendable to a meal re-timing intervention. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12616001556437 FUNDING: This work was funded by the National Health and Medical Research Council (NHMRC), APP1099077.

The effect of post-oral bitter compound interventions on the postprandial glycemia response: A systematic review and meta-analysis of randomised controlled trials.

BACKGROUND & AIMS: The post-oral sensing of bitter compounds by a family of bitter taste receptors (TAS2Rs) is suggested to regulate postprandial glycemia in humans. However, reports are inconsistent. This systematic review used meta-analysis to synthesise the impact of bitter compound interventions on the postprandial glycaemic response in humans. METHODS: Electronic databases (Medline, PubMed, and Web of Science) were systematically searched from inception to April 2024 to identify randomised controlled trials reporting the effect of interventions utilising post-oral bitter compounds vs. placebo on postprandial plasma glucose levels at t = 2 h (2 h-PPG), and area under the curve (AUC) of glucose, insulin, and c-peptide. The random-effect and subgroup analysis were performed to calculate pooled weighted mean differences (WMD), overall and by predefined criteria. RESULTS: Forty-six studies (within 34 articles) were identified; 29 and 17 studies described chronic and acute interventions, respectively. The chronic interventions reduced 2 h-PPG (n = 21, WMD = -0.35 mmol/L, 95%CIs = -0.58, -0.11) but not AUC for glucose or insulin. Subgroup analysis showed the former was particularly evident in individuals with impaired glycemia, interventions longer than three months, or quinine family administration. The acute interventions did not improve the postprandial glycemia response, but subgroup analysis revealed a decrease in AUC-glucose after quinine family administration (n = 4 WMD = -90.40 (nmol × time/L), 95%CIs = -132.70, -48.10). CONCLUSION: Chronic bitter compound interventions, particularly those from the quinine family, may have therapeutic potential in those with glycemia dysregulation. Acute intervention of the quinine family may also improve postprandial glucose. Given the very low quality of the evidence, further investigations with more rigorous methods are still required.

Effect of time restricted eating versus current practice in dietetics on glycaemic control and cardio-metabolic outcomes in individuals at risk of developing type 2 diabetes: Protocol for a multi-centre, parallel group, non-inferiority, randomised controlled trial.

BACKGROUND: Time restricted eating (TRE) is a dietary strategy that may improve metabolic health. However, no studies have compared TRE with current practice (CP) in dietetics. HYPOTHESIS: TRE will not be inferior to CP to improve glycaemic control in individuals at risk of type 2 diabetes (T2D). METHODS: This parallel group, randomised, non-inferiority, controlled trial randomised 247 participants by site and glycated haemoglobin (HbA1c) into TRE or CP (1:1) for 12 months. Participants were aged 35-70 years, with a body mass index (BMI) >25 but <45 kg/m2, and score ≥15 on the Australian type 2 diabetes risk (AUSDRISK) assessment, without a diagnosis of T2D. Study visits were balanced between groups and all participants received five consultations at 0, 0.5, 1, 2 and 3 months. TRE followed a self-selected 9 h eating window (≥0600 and ≤1900), whereas CP followed Australian dietary guidelines. OUTCOMES: The primary endpoint is the estimate of group mean difference (TRE vs CP) of HbA1c at 4 months in a covariate linear regression adjusting for stratification factors and sex. Secondary efficacy outcomes at 4 and 12 months are changes in fasting glucose, fasting insulin, HOMA-IR and nocturnal glucose by continuous glucose monitor incremental area under the curve and change in HbA1c at 12 months. Other endpoints are exploratory and will not be adjusted for multiplicity. CONCLUSIONS: We will determine whether TRE is an alternate strategy to current practice in dietetics to improve glucose control. TRIAL REGISTRATION: NCT04762251; 21 Feb 2021.

The effects of time-restricted eating versus habitual diet on inflammatory cytokines and adipokines in the general adult population: a systematic review with meta-analysis.

BACKGROUND: Time-restricted eating (TRE) may facilitate weight loss, but its impact on inflammation remains unclear. Chronic inflammation can detrimentally increase risk of obesity-associated comorbidities. OBJECTIVES: The aim of this systematic review was to synthesize and determine the effects of TRE on cytokine and adipokines (C-reactive protein [CRP], TNF alpha [TNF-α], interleukin-6 [IL-6], leptin, and adiponectin) in adults. METHODS: PubMed, Scopus, Cochrane CENTRAL, and Web of Science were systematically searched for randomized controlled trials (RCTs) and non-RCTs to determine the effects of TRE on cytokines and adipokines in adults up to 23 June, 2023. Risk of bias was assessed using risk of Bias 2 tool for RCTs and the ROBINS-I for non-RCTs. The standardized mean differences (SMDs) and their 95% confidence intervals (CIs) were estimated with the DerSimonian-Laird method through random-effect models. The PRISMA recommendations were followed. RESULTS: A total of 25 studies (13 RCTs, 12 non-RCTs) involving 936 participants were included. The pooled SMD for the effect of TRE compared with the control group on cytokines and adipokines was -0.11 (95% CI: -0.33, 0.12; I2 = 19.7%; n = 10 comparisons) for CRP; -0.25 (95% CI: -0.47, -0.03; I2 = 0%; n = 11 comparisons) for TNF-α; -0.09 (95% CI: -0.39, 0.21; I2 = 16.4%; n = 8 comparisons) for IL-6; -0.81 (95% CI: -1.37, -0.24; I2 = 65.3%; n = 5 comparisons) for leptin; and 0.07 (95% CI: -0.40, 0.54; I2 = 56.9%; n = 6 comparisons) for adiponectin. CONCLUSIONS: Time-restricted eating may be an effective approach to reduce TNF-α and leptin levels in the general adult population. This review was registered at PROSPERO as CRD42022358162.

Are e-Health Interventions Effective in Reducing Diabetes-Related Distress and Depression in Patients with Type 2 Diabetes? A Systematic Review with Meta-Analysis.

Background: e-Health refers to any health care service delivered through the internet or related technologies, to improve quality of life. Despite the increasing use of e-health interventions to manage type 2 diabetes (T2D), there is a lack of evidence about the effectiveness on diabetes distress and depression, which are common issues in those living with T2D. Purpose: To synthesize and determine the effects of e-health interventions on diabetes distress and depression among patients with T2D. Methods: We systematically searched PubMed, Scopus, Cochrane CENTRAL, and Web of Science for randomized controlled trials (RCTs), non-RCTs and observational cohort studies for the effects of e-health interventions on diabetes distress and depression in patients with T2D up to September 14, 2022. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 recommendations were followed. The risk of bias was assessed according to the Risk-of-Bias 2 tool (RCTs), the Risk Of Bias In Non-randomised Studies-of Interventions (ROBINS-I) (non-RCTs) and the National Institute of Health tool (observational). The standardized mean difference (SMD) and its related 95% confidence intervals (CIs) were estimated with the DerSimonian-Laird method through random-effect models. A pooled raw mean difference (MD) meta-analysis was conducted for RCTs comparing the effects of e-health versus control on diabetes distress screening to display the clinical impact. Results: A total of 41 studies (24 RCTs, 14 non-RCTs, and 3 observational) involving 8,667 individuals were included. The pooled SMD for the effect of e-health versus the control group on diabetes distress was -0.14 (95% CI = -0.24 to -0.04; I2 = 23.9%; n = 10 studies), being -0.06 (95% CI = -0.15 to 0.02; I2 = 7.8%; n = 16 studies) for depression. The pooled raw MD on diabetes distress screening showed a reduction of -0.54 points (95% CI = -0.81 to -0.27; I2 = 85.1%; n = 7 studies). Conclusion: e-Health interventions are effective in diminishing diabetes distress among adults with T2D, inducing clinically meaningful reductions.

A qualitative exploration of behaviour change and maintenance experience in people with overweight or obesity in a dietary intervention.

AIM: This qualitative study aimed to explore the experiences of participants who were enrolled in 6-month controlled weight loss interventions with 2-month follow-up to better understand the process of behaviour change and maintenance. METHODS: Fifteen participants who completed or dropped out from either a daily energy restriction or intermittent fasting group were recruited using maximum variation purposive sampling. In-depth, semi-structured interviews were conducted at the 2-month follow-up phase. All interviews were transcribed and analysed using thematic analysis, guided by behaviour change models including transtheoretical model, social cognitive theory and integrated model of change. RESULTS: Participants following both diets showed similar behaviour change patterns. Their first motivations were mostly external and relied on 'accountability' to adhere to the diet when initiating the dietary changes. Participants highlighted the importance of frequent reviews and monitoring in assisting their adherence. This feedback system promoted the development of self-efficacy and internalised motivation to encourage an 'ownership'. Participants who transitioned successfully from relying on accountability to take 'ownership' of the intervention were more capable of tackling challenges and tailoring their diet to form a new routine for long-term maintenance. CONCLUSION: External motivations were key to initiate while internalised motivations were more important to sustain the behaviour change. Health professionals can assist this process through routine monitoring and feedback processes in clinical practice.

The Impact of Obesity on Inflammatory Bowel Disease.

Obesity is prevalent in the inflammatory bowel disease (IBD) population, particularly in newly developed countries where both IBD and obesity in the general population are on the rise. The role of obesity in the pathogenesis of IBD was entertained but results from available studies are conflicting. It does, however, appear to negatively influence disease course whilst impacting on our medical and surgical therapies. The pro-inflammatory profile of the visceral adipose tissue might play a role in the pathogenesis and course of Crohn's Disease (CD). Interestingly, isolating the mesentery from the surgical anastomosis using a KONO-S technique significantly decreases anastomotic recurrence rate. Anti-obesity therapy is not widely used in IBD but was suggested as an adjunctive therapy in those patients. In this review, we aimed to highlight the epidemiology of obesity in IBD and to describe its influence on disease course and outcomes.

Effects of an Unripe Avocado Extract on Glycaemic Control in Individuals with Obesity: A Double-Blinded, Parallel, Randomised Clinical Trial.

BACKGROUND: Unripe avocados (Persea americana) are naturally enriched in mannoheptulose (MH), which is a candidate caloric restriction mimetic. OBJECTIVES: To evaluate the effects of a diet supplement made from unripe avocado on glucose tolerance, and cardiometabolic risk factors in free-living nondiabetic adults with obesity. METHODS: In a double-blinded, randomised controlled trial, 60 adults (female n = 47, age 48 ± 13 years, BMI 34.0 ± 2.6 kg/m2) were stratified by sex and randomised to avocado extract (AvX, 10 g finely ground, freeze-dried unripe avocado) or placebo (10 g finely ground cornmeal plus 5% spinach powder) daily, for 12 weeks. The primary outcome was a change in glucose area under the curve (AUC) in response to a 75 g oral glucose tolerance test. A post-hoc analysis was subsequently performed in a subgroup with insulin AUC above the median of baseline values after removal of participants >2 SD from the mean. RESULTS: There were no between-group differences in glucose AUC (p = 0.678), insulin AUC (p = 0.091), or cardiovascular outcomes. In the subgroup analysis, insulin AUC was lower in AxV versus placebo (p = 0.024). CONCLUSIONS: Daily consumption of unripe avocado extract enriched in MH did not alter glucose tolerance or insulin sensitivity in nondiabetic adults with obesity, but the data provided preliminary evidence for a benefit in insulin AUC in a subgroup of participants with elevated baseline postprandial insulin levels.

Basal autophagic flux measured in blood correlates positively with age in adults at increased risk of type 2 diabetes.

Preclinical data show that autophagy delays age-related disease. It has been postulated that age-related disease is-at least in part-caused by an age-related decline in autophagy. However, autophagic flux has never been measured in humans across a spectrum of aging in a physiologically relevant context. To address this critical gap in knowledge, the objective of this cross-sectional observational study was to measure basal autophagic flux in whole blood taken from people at elevated risk of developing type 2 diabetes and correlate it with chronological age. During this study, 119 people were recruited and five people were excluded during sample analysis such that 114 people were included in the final analysis. Basal autophagic flux measured in blood and correlations with parameters such as age, body weight, fat mass, AUSDRISK score, blood pressure, glycated hemoglobin HbA1c, blood glucose and insulin, blood lipids, high-sensitivity C-reactive protein, plasma protein carbonylation, and plasma ß-hexosaminidase activity were analysed. Despite general consensus in the literature that autophagy decreases with age, we found that basal autophagic flux increased with age in this human cohort. This is the first study to report measurement of basal autophagic flux in a human cohort and its correlation with age. This increase in basal autophagy could represent a stress response to age-related damage. These data are significant not only for their novelty but also because they will inform future clinical studies and show that measurement of basal autophagic flux in a human cohort is feasible.

A micro-randomized pilot study to examine the impact of just-in-time nudging on after-dinner snacking in adults with type 2 diabetes: A study protocol.

AIM: To determine whether a digital nudge soon after dinner reduces after-dinner snacking events as measured objectively by continuous glucose monitoring (CGM) in patients with type 2 diabetes (T2D). METHODS: This is a single-site micro-randomized trial (MRT). People with T2D, aged 18-75 years, managed with diet or a stable dose of oral antidiabetic medications for at least 3 months, and who habitual snack after dinner at least 3 nights per week, will be recruited. Picto-graphic nudges were designed by mixed research methods. After a 2-week lead-in phase to determine eligibility and snacking behaviours by a CGM detection algorithm developed by the investigators, participants will be micro-randomized daily (1:1) to a second 2-week period to either a picto-graphic nudge delivered-in-time (Intui Research) or no nudge. During lead-in and MRT phases, 24-hour glucose will be measured by CGM, sleep will be tracked by an under-mattress sleep sensor, and dinner timing will be captured daily by photographing the evening meal. RESULTS: The primary outcome is the difference in the incremental area under the CGM curve between nudging and non-nudging days during the period from 90 minutes after dinner until 04:00 AM. Secondary outcomes include the effect of baseline characteristics on treatment, and comparisons of glucose peaks and time-in-range between nudging and non-nudging days. The feasibility of 'just-in-time' messaging and nudge acceptability will be evaluated, along with the analysis of sleep quality measures and their night-to-night variability. CONCLUSIONS: This study will provide preliminary evidence of the impact of appropriately timed digital nudges on 24 -hour intertitial glucose levels resulting from altered after-dinner snacking in people with T2D. An exploratory sleep substudy will provide evidence of a bidirectional relationship between after-dinner snacking behaviour, glycaemia and sleep. Ultimately, this study will allow for the design of a future confirmatory study of the potential for digital nudging to improve health related behaviours and health outcomes.

Does hyperglycemia affect arginine metabolites in critically ill patients? A prospective cohort and in vitro study.

BACKGROUND: Changes in the arginine metabolites asymmetric dimethyl-L-arginine (ADMA) and L-homoarginine and acute blood glucose concentrations have been shown to cause endothelial dysfunction and be independently associated with mortality in Intensive Care Unit (ICU) patients. The aim of this study was to investigate whether hyperglycemia potentially modulates these arginine metabolite concentrations to provide a mechanism that may link hyperglycemia and mortality in this patient group. METHODS: A clinical and in vitro study were undertaken. Glucose, glycosylated hemoglobin-A1c (HbA1c) and the stress hyperglycemia ratio (SHR) (to quantify absolute, chronic and relative hyperglycemia respectively) were measured in 1155 acutely unwell adult patients admitted to a mixed medical-surgical ICU. SHR was calculated by dividing the admission glucose by the estimated average glucose over the last 3 months, which was derived from HbA1c. ADMA and L-homoarginine were measured in a plasma sample collected at admission to ICU by liquid chromatography tandem mass spectrometry. The activity of dimethylarginine-dimethylaminohydrolase 1 (DDAH1), the main enzyme regulating ADMA concentrations, was assessed at varying glucose concentrations in vitro by quantifying the conversion of ADMA to citrulline in HEK293 cells that overexpress DDAH1. RESULTS: In the clinical study, plasma ADMA was not significantly associated with any measure of hyperglycemia. L-homoarginine was positively associated with glucose (ß = 0.067, p = 0.018) and SHR (ß = 0.107, p < 0.001) after correction for glomerular filtration rate. However, as L-homoarginine is a negative predictor of mortality, the direction of these associations are the opposite of those expected if hyperglycemia was affecting mortality via changes in L-homoarginine. In vitro DDAH1 activity was not significantly influenced by glucose concentrations (p = 0.506). CONCLUSION: In critically ill patients the association between relative hyperglycemia and mortality is not mediated by changes in ADMA or L-homoarginine. Trial registration ANZCTR Trial ID ACTRN12615001164583.

Intermittent fasting plus early time-restricted eating versus calorie restriction and standard care in adults at risk of type 2 diabetes: a randomized controlled trial.

Intermittent fasting appears an equivalent alternative to calorie restriction (CR) to improve health in humans. However, few trials have considered applying meal timing during the 'fasting' day, which may be a limitation. We developed a novel intermittent fasting plus early time-restricted eating (iTRE) approach. Adults (N = 209, 58 ± 10 years, 34.8 ± 4.7 kg m-2) at increased risk of developing type 2 diabetes were randomized to one of three groups (2:2:1): iTRE (30% energy requirements between 0800 and 1200 hours and followed by a 20-h fasting period on three nonconsecutive days per week, and ad libitum eating on other days); CR (70% of energy requirements daily, without time prescription); or standard care (weight loss booklet). This open-label, parallel group, three-arm randomized controlled trial provided nutritional support to participants in the iTRE and CR arms for 6 months, with an additional 12-month follow-up. The primary outcome was change in glucose area under the curve in response to a mixed-meal tolerance test at month 6 in iTRE versus CR. Glucose tolerance was improved to a greater extent in iTRE compared with CR (-10.10 (95% confidence interval -14.08, -6.11) versus -3.57 (95% confidence interval -7.72, 0.57) mg dl-1 min-1; P = 0.03) at month 6, but these differences were lost at month 18. Adverse events were transient and generally mild. Reports of fatigue were higher in iTRE versus CR and standard care, whereas reports of constipation and headache were higher in iTRE and CR versus standard care. In conclusion, incorporating advice for meal timing with prolonged fasting led to greater improvements in postprandial glucose metabolism in adults at increased risk of developing type 2 diabetes. ClinicalTrials.gov identifier NCT03689608 .

Modifying Dietary Protein Impacts mTOR Signaling and Brain Deposition of Amyloid ß in a Knock-In Mouse Model of Alzheimer Disease.

BACKGROUND: Alzheimer disease (AD) is a neurodegenerative condition defined by the build-up of amyloid plaques in the brain and intraneuronal tangles of the protein tau. Autophagy is a cellular cleaning process involved in the degradation of proteins, including proteins directly responsible for amyloid plaques, but its activity is compromised in AD. The mechanistic target of rapamycin complex (mTORC) 1 inhibits autophagy when activated by amino acids. OBJECTIVES: We hypothesized that reducing amino acid intake by decreasing dietary protein could promote autophagy, which in turn could prevent amyloid plaque deposition in AD mice. METHODS: Homozygote (2-mo-old) and heterozygote (4-mo-old) amyloid precursor protein NL-G-F mice, a model of brain amyloid deposition, were used in this study to test this hypothesis. Male and female mice were fed with isocaloric low-protein, control, or high-protein diets for 4 mo and killed for analysis. Locomotor performance was measured using the inverted screen test, and body composition was measured using EchoMRI. Samples were analyzed using western blotting, enzyme-linked immunosorbent assay, mass spectrometry, and immunohistochemical staining. RESULTS: mTORC1 activity in the cerebral cortex was inversely covaried with protein consumption in both homozygote and heterozygote mice. Low-protein diet improved metabolic parameters and restored locomotor performance only in male homozygous mice. Dietary protein adjustment did not affect amyloid deposition in homozygous mice. However, in the heterozygous amyloid precursor protein NL-G-F mice, amyloid plaque was lower in male mice consuming the low protein compared with that in mice fed with the control diet. CONCLUSIONS: This study showed that reducing protein intake reduces mTORC1 activity and may prevent amyloid accumulation, at least in male mice. Moreover, dietary protein is a tool that can be used to change mTORC1 activity and amyloid deposition in the mouse brain, and the murine brain's response to dietary protein is sex specific.

Time-restricted eating alters the 24-hour profile of adipose tissue transcriptome in men with obesity.

OBJECTIVE: Time-restricted eating (TRE) restores circadian rhythms in mice, but the evidence to support this in humans is limited. The objective of this study was to investigate the effects of TRE on 24-hour profiles of plasma metabolites, glucoregulatory hormones, and the subcutaneous adipose tissue (SAT) transcriptome in humans. METHODS: Men (n = 15, age = 63 [4] years, BMI 30.5 [2.4] kg/m2 ) were recruited. A 35-hour metabolic ward stay was conducted at baseline and after 8 weeks of 10-hour TRE. Assessment included 24-hour profiles of plasma glucose, nonesterified fatty acid (NEFA), triglyceride, glucoregulatory hormones, and the SAT transcriptome. Dim light melatonin onset and cortisol area under the curve were calculated. RESULTS: TRE did not alter dim light melatonin onset but reduced morning cortisol area under the curve. TRE altered 24-hour profiles of insulin, NEFA, triglyceride, and glucose-dependent insulinotropic peptide and increased transcripts of circadian locomotor output cycles protein kaput (CLOCK) and nuclear receptor subfamily 1 group D member 2 (NR1D2) and decreased period circadian regulator 1 (PER1) and nuclear receptor subfamily 1 group D member 1 (NR1D1) at 12:00 am. The rhythmicity of 450 genes was altered by TRE, which enriched in transcripts for transcription corepressor activity, DNA-binding transcription factor binding, regulation of chromatin organization, and small GTPase binding pathways. Weighted gene coexpression network analysis revealed eigengenes that were correlated with BMI, insulin, and NEFA. CONCLUSIONS: TRE restored 24-hour profiles in hormones, metabolites, and genes controlling transcriptional regulation in SAT, which could underpin its metabolic health benefit.

Intermittent fasting increases growth differentiation factor 15 in females with overweight or obesity but not associated with food intake.

Growth differentiation factor 15 (GDF15) increases with acute fast in animals, and high GDF15 reduces food intake in rodents. We explored whether GDF15 was altered following intermittent fasting (IF) versus caloric restriction (CR), and associations with energy intake. Females with obesity received all foods at 70% (IF70 and CR70) or 100% of energy requirements for 8 weeks. IF ate 2-9% less than provided on refeeding days, resulting in greater weight losses. GDF15 was increased 5% more in IF70 versus CR70, but not associated with energy intake. This rise in GDF15 is unlikely to explain restriction of energy intake during IF.

Does intermittent fasting impact mental disorders? A systematic review with meta-analysis.

Accumulating evidence supports the benefits of intermittent fasting (IF) as a dietary strategy for cardiometabolic health and weight control. However, little is known about the potential implications of IF on mental disorders. The aim of this review was to synthesize evidence regarding the effects of IF on mental disorders (depression, anxiety, and mood state) in the general population. We conducted a systematic search in five databases from inception to January 2022. Randomized and nonrandomized clinical trials (RCTs/nonRCTs) were included. A random effects method was used to pool standardized mean differences (SMDs) and 95% CIs. A total of 14 studies involving 562 individuals were included, of which 8 were RCTs and 6 were nonRCTs. IF showed a moderate and positive effect on depression scores when compared to control groups (SMD: 0.41; 95%CI: 0.05 to 0.76; I2=45%; n = 4). Conversely, within-group analyses did not show any significant effect of IF on anxiety (SMD: 0.10; 95%CI: -0.09 to 0.30; I2=0%; n = 5) or mood state (SMD: 0.14; 95%CI: -0.09 to 0.37; I2=59%; n = 7). IF modalities did not negatively impact mental disorders in the general population. In fact, IF showed a positive influence on diminishing depression scores, and did not modify anxiety or mood.

The Break-Fast study protocol: a single arm pre-post study to measure the effect of a protein-rich breakfast on autophagic flux in fasting healthy individuals.

BACKGROUND: Autophagy is a cellular process that cleanses cells and is particularly important during ageing. Autophagy has been extensively studied in vitro and in animal models and is known to be sensitive to nutrition. However, human data are limited because autophagic flux (autophagic degradative activity) has been challenging to measure in humans. This protocol paper describes the Break-Fast study, in which autophagic flux will be measured using a recently developed blood test, before and after ingestion of whey protein. This aims to determine whether an acute nutritional intervention can change autophagy in humans. METHODS: A minimum of forty healthy participants (both male and female) aged 20-50 years, BMI 18.5-29.9 kg/m2 will be recruited into this single arm pre-post study. Participants will visit the clinic after an overnight fast for a first blood collection after which they will consume a whey protein-rich drink. A second blood collection will be performed 60 minutes after consumption of the drink. The primary outcome is the change in autophagic flux at 60 minutes post drink. Secondary outcomes include changes in blood glucose, autophagy-related proteins and mRNA, plasma hormones (e.g. insulin, C-peptide, adiponectin, GLP-1, GIP, ghrelin), cytokines, amino acids and lipids, protein synthesis, and correlation between molecular cell damage and autophagic flux. DISCUSSION: This study will provide information about whether autophagy responds to nutrients in humans, and if nutritional strategies could be used to treat or prevent autophagy-related diseases such as Alzheimer's disease or cancer. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR), anzctr.org.au ACTRN12621001029886. Registered on 5 August 2021.

Intermittent feeding and circadian rhythm in critical illness.

PURPOSE OF REVIEW: Circadian rhythms, i.e., periodic oscillations in internal biological processes, modulate metabolic processes such as hormonal signalling, nutrient absorption, and xenobiotic detoxification. Meal timing is a strong entraining cue for peripheral clocks in various organs, and eating out of circadian phases can impair glucose, gastrointestinal, and muscle metabolism. Sleep/wake cycles and circadian rhythms are extremely disrupted during critical illness. Timing of nutritional support may help preserve circadian rhythms and improve post-Intensive Care Unit (ICU) recovery. This review summarises circadian disruptors during ICU admission and evaluates the potential benefits of intermittent feeding on metabolism and circadian rhythms. RECENT FINDINGS: Rhythmic expression of core clock genes becomes rapidly disturbed during critical illness and remains disturbed for weeks. Intermittent, bolus, and cyclic enteral feeding have been directly compared to routine continuous feeding, yet no benefits on glycaemic control, gastrointestinal tolerance, and muscle mass have been observed and impacts of circadian clocks remain untested. SUMMARY: Aligning timing of nutritional intake, physical activity, and/or medication with circadian rhythms are potential strategies to reset peripheral circadian rhythms and may enhance ICU recovery but is not proven beneficial yet. Therefore, selecting intermittent feeding over continuous feeding must be balanced against the pros and cons of clinical practice.

Intermittent fasting activates markers of autophagy in mouse liver, but not muscle from mouse or humans.

OBJECTIVES: Intermittent fasting (IF) activates autophagy in cardiac muscle and pancreatic islets. We examined the effect of IF on markers of autophagy in liver and skeletal muscle in mice and in humans. METHODS: Ten-wk-old C57 BL/6 J male mice were ad libitum (AL) fed a high-fat diet (HFD) or chow diet for 8 wk, before randomization to AL or IF (24-h fast, 3 non-consecutive days per week) for 8 wk (8-16 per group). Tissue was collected in the fed or 22-h fasted state. Fifty women (51 ± 2 y, 31.8 ± 4.3 kg/m2) were randomly assigned to one of two IF protocols (24-hfast, 3 non-consecutive days per week) and fed at 70% (IF70) or 100% (IF100) of energy requirements for 8 wk. Vastus lateralis muscle was collected at 0800 after 12- and 24-h fasts. Microtubule-associated protein light chain 1 (Map1 lc3 b), Beclin1 (Becn1), Sequestosome 1 (Sqstm1/p62), and Lysosomal associated membrane protein 2 (Lamp2) were assessed by quantitative polymerase chain reaction and LC3, BECLIN1 and LAMP1 protein content by immunoblotting. RESULTS: Fasting increased hepatic LC3 I protein and Map1 lc3 b mRNA levels in IF mice fed chow or HFD. LAMP1 protein and Beclin1 mRNA levels in liver were also increased by fasting, but only in chow-fed mice. IF did not activate markers of autophagy in mouse muscle. In humans, a 24-h fast increased SQSTM1. BECLIN1, SQSTM1 and LAMP2 mRNA levels were decreased in IF70 after a 12-h overnight fast . CONCLUSION: Markers of autophagy in liver, but not in muscle, were elevated in response to IF in mice. In humans, autophagy markers in muscle were reduced, likely in response to weight loss.