Association between Time Restricted Feeding and Cognitive Status in Older Italian Adults

The influence of time-restricted eating/feeding on Alzheimer's biomarkers and gut microbiota

OBJECTIVES

Alzheimer's disease (AD) is a progressive neurodegenerative disorder affecting approximately 55 million individuals globally. Diagnosis typically occurs in advanced stages, and there are limited options for reversing symptoms. Preventive strategies are, therefore, crucial. Time Restricted Eating (TRE) or Time Restricted Feeding (TRF) is one such strategy. Here we review recent research on AD and TRE/TRF in addition to AD biomarkers and gut microbiota.

METHODS

A comprehensive review of recent studies was conducted to assess the impact of TRE/TRF on AD-related outcomes. This includes the analysis of how TRE/TRF influences circadian rhythms, beta-amyloid 42 (Aß42), pro-inflammatory cytokines levels, and gut microbiota composition.

RESULTS

TRE/TRF impacts circadian rhythms and can influence cognitive performance as observed in AD. It lowers beta-amyloid 42 deposition in the brain, a key AD biomarker, and reduces pro-ininflammatory cytokines. The gut microbiome has emerged as a modifiable factor in AD treatment. TRE/TRF changes the structure and composition of the gut microbiota, leading to increased diversity and a decrease in harmful bacteria.

DISCUSSION

These findings underscore the potential of TRE/TRF as a preventive strategy for AD. By reducing Aß42 plaques, modulating pro-inflammatory cytokines, and altering gut microbiota composition, TRE/TRF may slow the progression of AD. Further research is needed to confirm these effects and to understand the mechanisms involved. This review highlights TRE/TRF as a promising non-pharmacological intervention in the fight against AD.

Eating Frequency, Timing, and Duration in Relation to Cognitive Performance and Alzheimer Disease Biomarkers in Adults

BACKGROUND

The potential association between temporal dimensions of eating and cognition/cognitive declines has been poorly investigated so far.

OBJECTIVES

The aim of this study was to examine relationships among eating frequency, timing and time window, and cognitive performance and novel Alzheimer disease (AD) biomarkers in cognitively healthy and mildly cognitively impaired middle-aged and older adults.

METHODS

Cross-sectional data were derived from the Aiginition Longitudinal Biomarker Investigation of Neurodegeneration (ALBION) cohort study, including people aged 40 y or older who have a positive family history of cognitive disorder or cognition-related concerns. Cognitive performance was assessed by a battery of neuropsychological tests. Amyloid β (Αβ42), a biomarker of AD-related pathology, was measured in cerebrospinal fluid. Eating frequency, timing, and the eating time window between the first and the last meal were estimated using time-related information recorded in four 24-h recalls.

RESULTS

Study participants had, on average, 5.3 ± 1.2 eating episodes per day, consumed at 8:20 ± 1.3 and 21:14 ± 1.3 h their first and their last eating episode, respectively, while their eating time window was 12.9 ± 1.6 h. Eating frequency, but not eating time window, was positively associated with global cognition, executive and language performance even after controlling for age, sex, education, BMI, and Mediterranean diet. Increasing eating frequency by 1 eating episode per day was associated with 0.169 higher global z-score. Furthermore, compared with ≤4, having 5-6 or >6 eating episodes per day was associated with better global and memory z-scores. Time of last eating episode was also positively associated with language performance. No associations were detected among eating frequency, timing and window, and AD pathology.

CONCLUSIONS

An eating pattern characterized by less frequent eating and/or by earlier times is present in individuals with worse cognitive performance. Our results shed light on the relevance of temporal eating patterns as potential early markers of behavioral or metabolic changes related to AD pathology.

Effect of time-restricted eating and intermittent fasting on cognitive function and mental health in older adults: A systematic review

Objective

Emerging evidence suggests that dietary interventions hold promise for promoting cognitive function and mental well-being in aging populations. This systematic review aimed to examine the potential relationship between Time-Restricted Eating (TRE) and Intermittent Fasting (IFA) with cognitive function and mental health in older adults.

Methods

A thorough exploration was undertaken on electronic databases such as PubMed, Scopus, Web of Science, Science Direct, and Google Scholar, up to October 2023, following PRISMA standards. The evaluation of the quality and potential bias in the incorporated articles involved the use of the Newcastle-Ottawa Scale and Consolidated Standards of Reporting Trials (CONSORT).

Results

From a total of 539 articles initially identified, eight studies met the eligibility criteria for inclusion in this review. Out of these eight studies, six focused on cognitive function, and 2 focused on mental health. The reviewed articles encompassed a wide range of population sizes, with the number of older adults studied varying from 10 to 1357, reflecting a diverse cohort of individuals. Conclusions.The findings suggest that TRE and IFA may have a positive impact on cognitive function and mental health in this population. However, additional research is needed to fully comprehend this relationship. Therefore, future research should specifically examine factors such as the duration and timing of the eating window in TRE, as well as the physical condition of older adults, to provide a more nuanced understanding of the cognitive and mental health benefits of TRE and IFA in older adults.

A circadian rhythm-restricted diet regulates autophagy to improve cognitive function and prolong lifespan

Diet and circadian rhythms have been found to have a profound impact on health, disease, and aging. Skipping breakfast, eating late, and overeating have adverse effects on the body's metabolism and increase the risk of cardiovascular and metabolic diseases. Disturbance of circadian rhythms has been associated with increased risk of atherosclerosis, Alzheimer's disease, Parkinson's disease, and other diseases. Abnormal deposition of amyloid β (Aβ) and tau proteins in the brain and impaired synaptic function are linked to cognitive dysfunction. A restrictive diet following the circadian rhythm can affect the metabolism of lipids, glucose, and amino acids such as branched chain amino acids and cysteine. These metabolic changes contribute to autophagy through molecular mechanisms such as adenosine monophosphate-activated protein kinase (AMPK), rapamycin (mTOR), D-β-hydroxybutyrate (D-BHB), and neuropeptide Y (NPY). Autophagy, in turn, promotes the removal of abnormally deposited proteins and damaged organelles and improves cognitive function, ultimately prolonging lifespan. In addition, a diet restricted to the circadian rhythm induces increased expression of brain-derived neurotrophic factor (BDNF) in the forebrain region, regulating autophagy and increasing synaptic plasticity, thus enhancing cognitive function. Consequently, circadian rhythm-restricted diets could serve as a promising non-pharmacological treatment for preventing and improving cognitive dysfunction and prolonging lifespan.

The Role of Intermittent Fasting and Dieting on Cognition in Adult Population: A Systematic Review of the Randomized Controlled Trials

OBJECTIVE

A healthy diet is a modifiable risk factor that may impact cognition. A unique type of diet may include intermittent fasting (IF), an eating pattern in which individuals go extended periods with little or no meal intake, intervening with periods of normal food intake. IF has multiple health benefits including maintenance of blood glucose levels, reduction of insulin levels, depletion or reduction of glycogen stores, mobilization of fatty acids, and generation of ketones. IF has shown neuroprotective effects as it may lead to increased neurogenesis in the hippocampus, which may contribute to cognitive resilience. Diets including IF were examined as lifestyle modifications in the prevention and management of cognitive decline.

METHODS

A systematic literature search was conducted for randomized controlled trials (RCTs) which assessed the effect of dieting on cognitive functions in adults.

RESULTS

Dietary Approaches to Stop Hypertension (DASH), low-glycemic diets, and caloric restriction have shown improvement in cognitive function; however, there was a negative impact on problem-solving in those with comorbid cardiovascular disease. There is also contradictory evidence that caloric restriction and diet alone may not be sufficient for the improvement of cognitive functions and that exercise may have better efficacy on cognition.

CONCLUSION

IF is considered a safe intervention, and no adverse effects were found in the reviewed studies; however, evidence is limited as there were only 9 low-quality RCTs that assessed the impact of IF on cognition. DASH, low-glycemic diets, and exercise may have effective roles in the management and prevention of cognitive decline, although further research is needed.

Effects of time-restricted feeding and walking exercise on the physical health of female college students with hidden obesity: a randomized trial

Purpose

Time-restricted feeding (TRF) is an emerging dietary pattern with many potential effects. This study focused on the effects of TRF and walking on the physical health of female college students with hidden obesity.

Methods

A total of 77 female college students with hidden obesity, aged 18-22 years, were randomly assigned to a control group (CON, N = 19), time-restricted feeding group (TRF, N = 19), exercise group (EXE, N = 20), and TRF combined with exercise group (TRF + EXE, N = 19). The interventions lasted for 8 weeks. Tests assessing body shape, body composition, bone mineral density, blood lipid levels, and blood pressure were performed before and after the intervention.

Results

(1) Intragroup comparison before and after the intervention revealed that the TRF, EXE, and TRF + EXE groups had significantly reduced body weight (p < 0.01), body mass index (BMI) (p < 0.05), and lean tissue mass (LTM) (p < 0.01) but increased total cholesterol (TC) levels (p < 0.05) after the intervention. Body fat percentage (BF%) increased considerably in the EXE and TRF + EXE groups (p < 0.01). (2) Post-intervention comparisons of body weight, BMI, LTM, adipose tissue mass (ATM), total bone mineral density (TBMD), blood lipid levels, and blood pressure between the intervention groups (TRF, EXE, and TRF + EXE) and the CON group showed no significant differences (p > 0.05). (3) A comparison of the changes between the groups before and after the intervention showed significant decreases in body weight in the TRF and TRF + EXE groups (p < 0.05) and in both BMI and LTM in the TRF, EXE, and TRF + EXE groups (p < 0.05) compared to those in the CON group. The BF% change in the EXE and TRF + EXE groups were significantly greater than that in the TRF group (p < 0.01).

Conclusion

TRF effectively decreased body weight and BMI in female college students with hidden obesity. However, increased blood lipid levels and decreased LTM levels were also observed. The effects of TRF combined with exercise were not superior to those of TRF or walking alone in terms of body weight, body mass index, body composition, TBMD, or blood lipid levels. Therefore, TRF cannot be considered the best option for fat reduction in female college students with hidden obesity.

Dietary Fats and Cognitive Status in Italian Middle-Old Adults

The increase in life expectancy led to a significant rise in the prevalence of age-related neurological diseases, such as cognitive impairment, dementia, and Alzheimer’s disease. Although genetics certainly play a role, nutrition emerged as a key factor in maintaining optimal cognitive function among older adults. Therefore, the study aimed to investigate whether specific categories and subcategories of dietary fats, based on carbon-chain length, are associated with cognitive status in a cohort of 883 Italian participants over the age of 50. Methods: The intake of total, single class of dietary fat, such as saturated fatty acids (SFA), monounsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA), and also single fatty acids grouped according to carbon-chain length, were evaluated by food frequency questionnaires (FFQs). Cognitive health was assessed using the short portable mental status questionnaire (SPMSQ). Results: After adjustment for potential confounding factors subjects with a moderate consumption of both short-chain SFA (for Q2 vs. Q1, OR = 0.23, 95% CI: 0.08, 0.66) and middle-chain SFA specifically lauric acid (C12:0) intake (for Q2 vs. Q1, OR = 0.27, 95% CI: 0.09, 0.77) were less likely to suffer from cognitive impairment. Among single MUFAs, erucic acid (C22:1) intake resulted in an inverse association, in a linear way, with cognitive impairment (for Q4 vs. Q1, OR = 0.04, 95% CI: 0.00, 0.39). Conversely, moderate intake of linoleic acid (C18:2) was associated with cognitive impairment (Q3 vs. Q1, OR = 4.59, 95% CI: 1.51, 13.94). Regarding other PUFAs, individuals consuming moderate intake alpha linolenic acid (C18:3) were less likely to have cognitive impairment (for Q3 vs. Q1, OR = 0.19, 95% CI: 0.06, 0.64). Conclusions: Total SFA intake appeared to be inversely associated with cognitive impairment. Regarding specific subtypes of fatty acids, the results mostly referred to short- and middle-chain SFA. Further studies are needed to validate the results of the present study.

Daily Energy Intake Distribution and Cognitive Performance in Non-Demented Individuals

Cognitive disorders have become important public health issues around the world. Studies evaluating the association between cognitive decline and food timing are lacking. The objective of this study was to examine the potential association between energy intake distribution during the day and cognitive performance in cognitively healthy and mildly cognitive impaired individuals. Data were derived from the ongoing Albion study which includes people aged 40 years or older who have a positive family history of cognitive disorder or concern about their cognitive status. A thorough dietary and cognitive assessment was performed. Participants consuming low energy intake at the beginning of the day or high energy at the end of the day had higher cognitive function compared to participants characterized by the opposite pattern. This trend remained statistically significant even after adjustment for potential confounders (p = 0.043). This study suggests that individuals with worse cognitive function may choose to eat earlier during the day, when cognitive performance is better, and it might be hypothesized that a meal pattern characterized by high energy consumption at the beginning of the day or low energy at the end of the day could be a marker of cognitive impairment.

Different patterns of changes in free 25-hydroxyvitamin D concentrations during intermittent fasting among meat eaters and non-meat eaters and correlations with amino acid intake

We prospectively assessed changes in free 25-hydroxyvitamin D [25(OH)D] and vitamin D binding protein (VDBP) among overweight adults who followed a pescatarian Orthodox intermittent fasting regimen (n = 59) and controls who followed a low-fat 12:12 diet (n = 46). Total and free 25(OH)D, parathyroid hormone, VDBP, anthropometric data, and amino acid intake were evaluated in both groups at three time points: at baseline, 7 weeks after diet implementation, and 5 weeks after participants returned to their usual eating habits (12 weeks from baseline). An increase in amino acid intake between baseline and 12 weeks was independently correlated with higher free 25(OH)D values at 12 weeks for both groups. Our findings suggest that diet can affect free 25(OH)D concentrations, through variations in amino acid intake, independently of exposure to sunlight, providing novel mechanistic insights into the future planning of vitamin D supplementation strategies. However, this hypothesis needs to be tested in larger studies.

Time restricted feeding is associated with poor performance in specific cognitive domains of Suburb-Dwelling older Chinese

The purpose of this study was to investigate the association between time restricted feeding (TRF) and different areas of cognitive function in the elderly in Chinese communities. This study consisted of 1353 community-dwelling Chinese older adults aged 60 years and older in Chongming area, Shanghai (563 males; the mean age, 73.38 ± 6.16 years). Mild cognitive impairment (MCI) and six different cognitive domains was assessed by the Chinese-version of Mini Mental State Examination (MMSE). Recording the eating time of each meal through oral inquiry to calculate the time window between the first meal and the last meal of the average day. Participants with an eating time window duration of more than 10 h were then identified, as well as those with eating time restricted to less than 10 h (TRF). Our study found that TRF may be associated with a higher incidence rate of cognitive impairment. TRF only limited the eating time window and did not change the frequency of participants' dietary intake. We used a linear regression model to study the association of TRF with cognitive function. After adjusting for confounding variables, the results showed that TRF was related to MMSE score (P < 0.001), "Orientation to place" (P < 0.001) and "Attention/calculation" (P < 0.001) functions. Among Chinese older community-dwellers, TRF was associated with a higher prevalence of CI and negatively correlated with the "Orientation to place" and "attention/calculation" functions.

Nutrition, Food and Diet in Health and Longevity: We Eat What We Are

Nutrition generally refers to the macro- and micro-nutrients essential for survival, but we do not simply eat nutrition. Instead, we eat animal- and plant-based foods without always being conscious of its nutritional value. Furthermore, various cultural factors influence and shape our taste, preferences, taboos and practices towards preparing and consuming food as a meal and diet. Biogerontological understanding of ageing has identified food as one of the three foundational pillars of health and survival. Here we address the issues of nutrition, food and diet by analyzing the biological importance of macro- and micro-nutrients including hormetins, discussing the health claims for various types of food, and by reviewing the general principles of healthy dietary patterns, including meal timing, caloric restriction, and intermittent fasting. We also present our views about the need for refining our approaches and strategies for future research on nutrition, food and diet by incorporating the molecular, physiological, cultural and personal aspects of this crucial pillar of health, healthy ageing and longevity.

Early time-restricted eating may favorably impact cognitive acuity in university students: a randomized pilot study

Cognitive acuity is important for academic success. The preliminary efficacy of early time-restricted eating (eTRE) on cognitive acuity was examined in a sample of university students attending a large southwestern university. It was hypothesized that adherence to eTRE would result in improved cognitive acuity as assessed by the Trail Making Tests (i.e., TMT-A and TMT-B) and the Stroop Color and Word Test. Participants were randomized to an intervention group (eTRE) with a daily 6-hour eating window or a control group (CON) with a daily 16-hour eating window; 24 participants initiated the study (13 eTRE and 11 CON). Blood ketones (i.e., β-hydroxybutyrate [BHB]) and brain-derived neurotrophic factor were also assessed. The 8-week intervention was forestalled by COVID-19 laboratory closures beginning in March 2020, and only data obtained at week 0 (baseline) and week 4 were viable for statistical analyses. Study attrition was high (50% for eTRE and 23% for CON). At week 4, there was a 27% and 6% decrease in TMT-B response time for the eTRE and CON groups, respectively (P = .02). TMT-B response time was inversely correlated to plasma BHB among participants (r = -0.633; P = .008). Considering the inverse relationship between TMT-B response time and plasma BHB, these preliminary data suggest that eTRE may improve some aspects of cognitive acuity in this population. Future investigations are needed to confirm these findings and should accommodate individual preferences regarding the initiation time of the eating window while also considering the impact on social influences and exercise engagement.

Dietary Restriction against Parkinson's Disease: What We Know So Far

Dietary restriction (DR) is defined as a moderate reduction in food intake while avoiding malnutrition. The beneficial effects of DR are being increasingly acknowledged in aging and in a series of age-related neurodegenerative disorders, for example, Parkinson's disease (PD). To date, the pathogenesis of PD remains elusive and there is no cure for it in spite of intensive research over decades. In this review, we summarize the current knowledge on the efficacy of DR on PD, focusing on the underlying mechanisms involving general metabolism, neuroendocrinolgy, neuroinflammation, gut microbiome, and so on. We anticipate that this review will provide future perspectives for PD prevention and treatment.

The association of diet carbohydrates consumption with cognitive function among US older adults modification by daily fasting duration

Dietary carbohydrate consumption was related to cognitive function. Whereas, there was no study investigate the association of dietary carbohydrate consumption with cognitive function modification by daily fasting duration. This study aims to examine the association between dietary carbohydrate consumption and cognitive function among participants with different daily fasting duration. In this cross-sectional study, 2485 adults aged over 60 years from the nationally representative data of the National Health and Nutrition Examination Survey (NHANES, 2011–2014) were enrolled. Percentage energy from carbohydrates was present in both quartiles and continuous forms. Daily fasting duration = 24 – (timing for dinner – breakfast). Cognitive function was assessed by the Consortium to Establish a Registry for Alzheimer’s Disease Word List Learning (CERAD-WL), CERAD Word List Delayed Recall (CERAD-DR), Animal Fluency (AF), and Digit Symbol Substitution (DSST) Test. Multiple logistic regression and linear regression models were developed to examine the association of dietary carbohydrates with cognitive function among participants with different daily fasting duration. Restricted cubic spline models were also applied. Compared with the lowest quartile of percentage energy from carbohydrates, the highest quartile had higher ORs of poor cognitive performance among total participants [(ORCERAD-WL 1.84 95% CI 1.25–2.71); (ORCERAD-DR 1.45 95% CI 1.10–1.91)] and participants with daily fasting duration fewer than 16 h [(ORCERAD-WL 2.14 95% CI 1.29–3.55); (ORCERAD-DR 1.51 95% CI 1.05–2.17)] but not in participants with daily fasting duration of more than 16 h. Further, the negative associations between percentage energy from carbohydrates and CERAD-WL score were still significant in addition to participants whose daily fasting duration was more than 16 h. Additionally, dose-response associations were detected between dietary carbohydrates and cognitive decline, while “U” curves were observed among participants whose daily fasting duration was more than 16 h. This study indicated that dietary carbohydrates consumption was associated with poor cognitive performance, but not in participants whose daily fasting duration was more than 16 h among US older adults. The current analysis provides evidence that a longer daily fasting duration may improve the harmful effect of dietary carbohydrates on cognitive function.

A Bibliometric and Visualization Analysis of Intermittent Fasting

CiteSpace software was utilized to visually analyze the literature on intermittent fasting from Web of Science from 2000 to 2020 in order to reveal the current status, research hotspots and emerging trends of intermittent fasting. The results show that: (1) intermittent fasting research results are increasing year by year; (2) the United States is at the core of this field and has a high influence; (3) intermittent fasting research is mainly concentrated in the fields of nutrition, cell biology and kinesiology, which embodies interdisciplinary characteristics; (4) the literature of Sutton, Mattson and Trepanowski that were published in the same period have the highest co-citation frequencies, however, their research perspectives are quite different, reflecting that the research in this field is still in a state of continuous development; (5) from the perspective of citation bursts, the evolution of research hotspots in this field in the last 20 years can be divided into 3 stages; (6) the keyword timeline mapping shows that time restricted feeding is at the forefront of this research field. This study can help researchers explore the field for the first time to quickly grasp the frontiers and obtain more valuable data, thereby providing facilitation for the follow-up research.

Therapeutic Fasting: Are Patients Aged 65 and Over Ready?

While being the main potential beneficiaries of therapeutic fasting’s health benefits, the elderly are frequently thought of as being too fragile to fast. The main objective of our survey was to review the knowledge, practices, and acceptability of therapeutic fasting in subjects aged 65 years and over. From September 2020 to March 2021, an online questionnaire was sent to subjects aged 65 and over, using the mailing list of local organizations working in the field of aging. The mean age of the 290 respondents was 73.8 ± 6.5 years, 75.2% were women and 54.1% had higher education. Among the respondents, 51.7% had already fasted and 80.7% deemed therapeutic fasting interesting, 83.1% would be willing to fast if it was proven beneficial for their health, and 77.2% if it was proven to decrease the burden of chronic diseases. Subjects aged 65 to 74 years considered themselves as having the greatest physical and motivational abilities to perform therapeutic fasting. People aged 65 years, or more, are interested in therapeutic fasting and a large majority would be ready to fast if such practice was proven beneficial. These results pave the way for future clinical trials evaluating therapeutic fasting in elderly subjects.

Assessing temporal eating pattern in free living humans through the myCircadianClock app

The quality and quantity of nutrition impact health. However, chrononutrition, the timing, and variation of food intake in relation to the daily sleep-wake cycle are also important contributors to health. This has necessitated an urgent need to measure, analyze, and optimize eating patterns to improve health and manage disease. While written food journals, questionnaires, and 24-hour dietary recalls are acceptable methods to assess the quantity and quality of energy consumption, they are insufficient to capture the timing and day-to-day variation of energy intake. Smartphone applications are novel methods for information-dense real-time food and beverage tracking. Despite the availability of thousands of commercial nutrient apps, they almost always ignore eating patterns, and the raw real-time data is not available to researchers for monitoring and intervening in eating patterns. Our lab developed a smartphone app called myCircadianClock (mCC) and associated software to enable long-term real-time logging that captures temporal components of eating patterns. The mCC app runs on iOS and android operating systems and can be used to track multiple cohorts in parallel studies. The logging burden is decreased by using a timestamped photo and annotation of the food/beverage being logged. Capturing temporal data of consumption in free-living individuals over weeks/months has provided new insights into diverse eating patterns in the real world. This review discusses (1) chrononutrition and the importance of understanding eating patterns, (2) the myCircadianClock app, (3) validation of the mCC app, (4) clinical trials to assess the timing of energy intake, and (5) strengths and limitations of the mCC app.

Effects of Intermittent Fasting on Brain Metabolism

We are facing an obesity epidemic, and obesity itself and its close companion, type 2 diabetes, are independent risk factors for neurodegeneration. While most medical treatments fail to induce a clinically meaningful improvement in neurodegenerative disorders, lifestyle interventions have emerged in the spotlight. A recently rediscovered approach is intermittent fasting (IF), which, compared to the classic caloric restriction regimens, limits only the time of eating, rather than the number of calories allowed per day. There is already a large amount of evidence from preclinical and clinical studies showing the beneficial effects of IF. In this review, we specifically focus on the effects of IF on brain metabolism. Key molecular players modified during IF and involved in its beneficial central effects (ketone bodies, BDNF, GABA, GH/IGF-1, FGF2, sirtuin-3, mTOR, and gut microbiota) are identified and discussed. Studies suggest that IF induces several molecular and cellular adaptations in neurons, which, overall, enhance cellular stress resistance, synaptic plasticity, and neurogenesis. Still, the absence of guidelines regarding the application of IF to patients hampers its broad utilization in clinical practice, and further studies are needed to improve our knowledge on the different IF protocols and long-term effects of IF on brain metabolism before it can be widely prescribed.

The neuroprotective effects of intermittent fasting on brain aging and neurodegenerative diseases via regulating mitochondrial function

Intermittent fasting (IF) has been studied for its effects on lifespan and the prevention or delay of age-related diseases upon the regulation of metabolic pathways. Mitochondria participate in key metabolic pathways and play important roles in maintaining intracellular signaling networks that modulate various cellular functions. Mitochondrial dysfunction has been described as an early feature of brain aging and neurodegeneration. Although IF has been shown to prevent brain aging and neurodegeneration, the mechanism is still unclear. This review focuses on the mechanisms by which IF improves mitochondrial function, which plays a central role in brain aging and neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. The cellular and molecular mechanisms of IF in brain aging and neurodegeneration involve activation of adaptive cellular stress responses and signaling- and transcriptional pathways, thereby enhancing mitochondrial function, by promoting energy metabolism and reducing oxidant production.

Adult Neurogenesis under Control of the Circadian System

The mammalian circadian system is a hierarchically organized system, which controls a 24-h periodicity in a wide variety of body and brain functions and physiological processes. There is increasing evidence that the circadian system modulates the complex multistep process of adult neurogenesis, which is crucial for brain plasticity. This modulatory effect may be exercised via rhythmic systemic factors including neurotransmitters, hormones and neurotrophic factors as well as rhythmic behavior and physiology or via intrinsic factors within the neural progenitor cells such as the redox state and clock genes/molecular clockwork. In this review, we discuss the role of the circadian system for adult neurogenesis at both the systemic and the cellular levels. Better understanding of the role of the circadian system in modulation of adult neurogenesis can help develop new treatment strategies to improve the cognitive deterioration associated with chronodisruption due to detrimental light regimes or neurodegenerative diseases.

Differential Effects of One Meal per Day in the Evening on Metabolic Health and Physical Performance in Lean Individuals

Background: Generally, food intake occurs in a three-meal per 24 h fashion with in-between meal snacking. As such, most humans spend more than ∼ 12-16 h per day in the postprandial state. It may be reasoned from an evolutionary point of view, that the human body is physiologically habituated to less frequent meals. Metabolic flexibility (i.e., reciprocal changes in carbohydrate and fatty acid oxidation) is a characteristic of metabolic health and is reduced by semi-continuous feeding. The effects of time-restricted feeding (TRF) on metabolic parameters and physical performance in humans are equivocal. Methods: To investigate the effect of TRF on metabolism and physical performance in free-living healthy lean individuals, we compared the effects of eucaloric feeding provided by a single meal (22/2) vs. three meals per day in a randomized crossover study. We included 13 participants of which 11 (5 males/6 females) completed the study: age 31.0 ± 1.7 years, BMI 24.0 ± 0.6 kg/m² and fat mass (%) 24.0 ± 0.6 (mean ± SEM). Participants consumed all the calories needed for a stable weight in either three meals (breakfast, lunch and dinner) or one meal per day between 17:00 and 19:00 for 11 days per study period. Results: Eucaloric meal reduction to a single meal per day lowered total body mass (3 meals/day -0.5 ± 0.3 vs. 1 meal/day -1.4 ± 0.3 kg, p = 0.03), fat mass (3 meals/day -0.1 ± 0.2 vs. 1 meal/day -0.7 ± 0.2, p = 0.049) and increased exercise fatty acid oxidation (p < 0.001) without impairment of aerobic capacity or strength (p > 0.05). Furthermore, we found lower plasma glucose concentrations during the second half of the day during the one meal per day intervention (p < 0.05). Conclusion: A single meal per day in the evening lowers body weight and adapts metabolic flexibility during exercise via increased fat oxidation whereas physical performance was not affected.

Chrononutrition in Cardiometabolic Health

In recent years, a healthy balanced diet together with weight reduction has risen to the forefront of minimizing the impact of cardiovascular disease. There is evidence that metabolic processes present circadian rhythmicity. Moreover, the timing of food consumption exerts a powerful influence on circadian rhythms. In this context, the subject of chrononutrition, described as the alignment of timing of food intake to the rhythms imposed by the circadian clock, has attracted considerable interest for possible beneficial effects on cardiovascular health. Current human studies suggest that chrononutrition-based dietary interventions could reduce the risk for cardiovascular disease by improving weight control, hypertension, dyslipidemia, and diabetes. However, meta-analysis of randomized control trials in this topic present varying and somehow conflicting results. Even the traditional association of breakfast skipping with adverse cardiovascular outcomes is nowadays controversial. Therefore, long-term and fairly consistent studies on the effect of chrononutrition on cardiovascular outcomes are needed. The purpose of this review is to provide concise evidence of the most recent literature involving the effects of chrononutrition and the specific chrononutrition-based dietary interventions, in particular time-restricted eating, on body weight and other cardiovascular disease risk factors.

A Growing Link between Circadian Rhythms, Type 2 Diabetes Mellitus and Alzheimer's Disease

Type 2 diabetes mellitus (T2DM) patients are at a higher risk of developing Alzheimer’s disease (AD). Mounting evidence suggests the emerging important role of circadian rhythms in many diseases. Circadian rhythm disruption is considered to contribute to both T2DM and AD. Here, we review the relationship among circadian rhythm disruption, T2DM and AD, and suggest that the occurrence and progression of T2DM and AD may in part be associated with circadian disruption. Then, we summarize the promising therapeutic strategies targeting circadian dysfunction for T2DM and AD, including pharmacological treatment such as melatonin, orexin, and circadian molecules, as well as non-pharmacological treatments like light therapy, feeding behavior, and exercise.

Dissociation between Corneal and Cardiometabolic Changes in Response to a Time-Restricted Feeding of a High Fat Diet

Mice fed a high fat diet (HFD) ab libitum show corneal dysregulation, as evidenced by decreased sensitivity and impaired wound healing. Time-restricted (TR) feeding can effectively mitigate the cardiometabolic effects of an HFD. To determine if TR feeding attenuates HFD-induced corneal dysregulation, this study evaluated 6-week-old C57BL/6 mice fed an ad libitum normal diet (ND), an ad libitum HFD, or a time-restricted (TR) HFD for 10 days. Corneal sensitivity was measured using a Cochet-Bonnet aesthesiometer. A corneal epithelial abrasion wound was created, and wound closure was monitored for 30 h. Neutrophil and platelet recruitment were assessed by immunofluorescence microscopy. TR HFD fed mice gained less weight (p < 0.0001), had less visceral fat (p = 0.015), and had reduced numbers of adipose tissue macrophages and T cells (p < 0.05) compared to ad libitum HFD fed mice. Corneal sensitivity was reduced in ad libitum HFD and TR HFD fed mice compared to ad libitum ND fed mice (p < 0.0001). Following epithelial abrasion, corneal wound closure was delayed (~6 h), and neutrophil and platelet recruitment was dysregulated similarly in ad libitum and TR HFD fed mice. TR HFD feeding appears to mitigate adipose tissue inflammation and adiposity, while the cornea remains sensitive to the pathologic effects of HFD feeding.

Association between Irregular Meal Timing and the Mental Health of Japanese Workers

Breakfast skipping and nighttime snacking have been identified as risk factors for obesity, diabetes, and cardiovascular diseases. However, the effects of irregularity of meal timing on health and daily quality of life are still unclear. In this study, a web-based self-administered questionnaire survey was conducted involving 4490 workers (73.3% males; average age = 47.4 ± 0.1 years) in Japan to investigate the association between meal habits, health, and social relationships. This study identified that irregular meal timing was correlated with higher neuroticism (one of the Big Five personality traits), lower physical activity levels, and higher productivity loss. Irregular meal timing was also associated with a higher incidence of sleep problems and lower subjective health conditions. Among health outcomes, a high correlation of irregular meal timing with mental health factors was observed. This study showed that irregularity of meal timing can be explained by unbalanced diets, frequent breakfast skipping, increased snacking frequency, and insufficient latency from the last meal to sleep onset. Finally, logistic regression analysis was conducted, and a significant contribution of meal timing irregularity to subjective mental health was found under adjustment for other confounding factors. These results suggest that irregular meal timing is a good marker of subjective mental health issues.

Implementation of Christian Orthodox fasting improves plasma adiponectin concentrations compared with time-restricted eating in overweight premenopausal women

The exact mechanisms mediating the metabolic effects of Orthodox fasting remain unclear. Plasma adiponectin, biochemical and anthropometrical data were evaluated in 55 Orthodox fasters (OF) and 42 time-restricted eating controls (all women, mean age 47.8 years) at three time points: baseline, end of the dietary intervention (7 weeks) and 5 weeks after participants returned to their typical dietary habits (12 weeks from baseline). In the OF group, there was an increase in adiponectin values at 12 weeks compared with baseline (9815.99 vs 8983.52 mg/ml, p = 0.02) and a reduction in body fat mass between baseline and 12 weeks (35.44 vs 32.17%, p = 0.004) and between 7 and 12 weeks (35.33 vs 32.17%, p = 0.003). In the same group, an inverse correlation between adiponectin and waist circumference values was observed over the entire study period. Our results provide novel evidence that Orthodox fasting has favourable metabolic effects related to improved adiponectin concentrations.

Fasting: How to Guide

Fasting potentials are the most interesting topics in the Nutritional Era. Fasting consists of the catabolism of lipids, proteins, and carbohydrates to maintain blood glucose levels in a normal range. The action mechanisms of fasting were firstly understood in minor organisms and later in humans. Nutritional interventions of caloric restriction could attenuate age-associated epigenetic alterations and could have a protective effect against cellular alterations, promoting longevity and health span. While most fasting studies point out the weight and fat mass decreases, it is important to define specific guidelines for fasting and non-fasting days to enhance adherence, minimize the dropout rates of the interventions, and maximize body composition improvement. Although the panorama of evidence on fasting and caloric restriction is wide, there is a lack of a safe fasting protocol to guide physicians in its prescription. The main goal is to identify a how to use guide, a major posology of fasting, inserted within a huge dietetic personalized strategy leading to an optimal and healthy nutritional status.

Nutritional Psychiatry: How Diet Affects Brain through Gut Microbiota

Nutritional sciences have been recognized as being of paramount importance for the prevention of non-communicable diseases. Among others, mental health disorders have been hypothesized to be influenced by dietary risk through a variety of molecular mechanisms. The improvements in the technology and implementation of-omics sciences in terms of nutrition have created the possibility of studying the relation between diet, gut microbiota and mental health. The gut–brain–axis represents the core rationale setting the stage for a relatively new discipline of study defined as “nutritional psychiatry”. Research on this matter will help to better understand the relation between food and mood, sleep quality, cognition, and mental health in general.

The Christian Orthodox Church Fasting Diet Is Associated with Lower Levels of Depression and Anxiety and a Better Cognitive Performance in Middle Life

Lifestyle choices significantly influence mental health in later life. In this study we investigated the effects of the Christian Orthodox Church (COC) fasting diet, which includes long-term regular abstinence from animal-based products for half the calendar year, on cognitive function and emotional wellbeing of healthy adults. Two groups of fasting and non-fasting individuals were evaluated regarding their cognitive performance and the presence of anxiety and depression using the Mini Mental Examination Scale, the Hamilton Anxiety Scale, and the Geriatric Depression Scale (GDS), respectively. Data on physical activity, smoking, and vitamin levels were collected and correlated with mental health scoring. Negative binomial regression was performed to examine differences in the GDS scores between the two groups. Significantly lower levels of anxiety (7.48 ± 4.98 vs. 9.71 ± 5.25; p < 0.001) and depression (2.24 ± 1.77 vs. 3.5 ± 2.52; p < 0.001), along with better cognitive function (29.15 ± 0.79 vs. 28.64 ± 1.27; p < 0.001), were noticed in fasting compared to non-fasting individuals. GDS score was 31% lower (Incidence Rate Ratio: 0.69, 95% Confidence Interval: 0.56–0.85) in the fasting group compared to the control, while vitamin and ferrum levels did not differ. The COC fasting diet was found to have an independent positive impact on cognition and mood in middle-aged and elderly individuals.