Energy intake, meal frequency, and health: a neurobiological perspective

Effect of Calorie Restriction and Intermittent Fasting Regimens on Brain-Derived Neurotrophic Factor Levels and Cognitive Function in Humans: A Systematic Review

Background: The potential positive interaction between intermittent fasting (IF) and brain-derived neurotrophic factor (BDNF) on cognitive function has been widely discussed. This systematic review tried to assess the efficacy of interventions with different IF regimens on BDNF levels and their association with cognitive functions in humans. Interventions with different forms of IF such as caloric restriction (CR), alternate-day fasting (ADF), time-restricted eating (TRE), and the Ramadan model of intermittent fasting (RIF) were targeted. Methods: A systematic review was conducted for experimental and observational studies on healthy people and patients with diseases published in EMBASE, Scopus, PubMed, and Google Scholar databases from January 2000 to December 2023. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statements (PRISMA) for writing this review. Results: Sixteen research works conducted on healthy people and patients with metabolic disorders met the inclusion criteria for this systematic review. Five studies showed a significant increase in BDNF after the intervention, while five studies reported a significant decrease in BDNF levels, and the other six studies showed no significant changes in BDNF levels due to IF regimens. Moreover, five studies examined the RIF protocol, of which, three studies showed a significant reduction, while two showed a significant increase in BDNF levels, along with an improvement in cognitive function after RIF. Conclusions: The current findings suggest that IF has varying effects on BDNF levels and cognitive functions in healthy, overweight/obese individuals and patients with metabolic conditions. However, few human studies have shown that IF increases BDNF levels, with controversial results. In humans, IF has yet to be fully investigated in terms of its long-term effect on BDNF and cognitive functions. Large-scale, well-controlled studies with high-quality data are warranted to elucidate the impact of the IF regimens on BDNF levels and cognitive functions.

Misalignment of Circadian Rhythms in Diet-Induced Obesity

The biological clocks of the circadian timing system coordinate cellular and physiological processes and synchronize them with daily cycles. While the central clock in the suprachiasmatic nucleus (SCN) is mainly synchronized by the light/dark cycles, the peripheral clocks react to other stimuli, including the feeding/fasting state, nutrients, sleep-wake cycles, and physical activity. During the disruption of circadian rhythms due to genetic mutations or social and occupational obligations, incorrect arrangement between the internal clock system and environmental rhythms leads to the development of obesity. Desynchronization between the central and peripheral clocks by altered timing of food intake and diet composition leads to uncoupling of the peripheral clocks from the central pacemaker and to the development of metabolic disorders. The strong coupling of the SCN to the light-dark cycle creates a situation of misalignment when food is ingested during the "wrong" time of day. Food-anticipatory activity is mediated by a self-sustained circadian timing, and its principal component is a food-entrainable oscillator. Modifying the time of feeding alone greatly affects body weight, whereas ketogenic diet (KD) influences circadian biology, through the modulation of clock gene expression. Night-eating behavior is one of the causes of circadian disruption, and night eaters have compulsive and uncontrolled eating with severe obesity. By contrast, time-restricted eating (TRE) restores circadian rhythms through maintaining an appropriate daily rhythm of the eating-fasting cycle. The hypothalamus has a crucial role in the regulation of energy balance rather than food intake. While circadian locomotor output cycles kaput (CLOCK) expression levels increase with high-fat diet-induced obesity, peroxisome proliferator-activated receptor-alpha (PPARα) increases the transcriptional level of brain and muscle aryl hydrocarbon receptor nuclear translocator (ARNT)-like 1 (BMAL1) in obese subjects. In this context, effective timing of chronotherapies aiming to correct SCN-driven rhythms depends on an accurate assessment of the SCN phase. In fact, in a multi-oscillator system, local rhythmicity and its disruption reflects the disruption of either local clocks or central clocks, thus imposing rhythmicity on those local tissues, whereas misalignment of peripheral oscillators is due to exosome-based intercellular communication.Consequently, disruption of clock genes results in dyslipidemia, insulin resistance, and obesity, while light exposure during the daytime, food intake during the daytime, and sleeping during the biological night promote circadian alignment between the central and peripheral clocks. Thus, shift work is associated with an increased risk of obesity, diabetes, and cardiovascular diseases because of unusual eating times as well as unusual light exposure and disruption of the circadian rhythm.

Dietary Restriction Delays But Cannot Heal Irradiation-Induced Hair Graying by Preserving Hair Follicle Stem Cells in Quiescence

DNA damage represents one of the cell intrinsic causes of stem cell aging, which leads to differentiation-induced removal of damaged stem cells in skin and blood. Dietary restriction (DR) retards aging across various species, including several strains of laboratory mice. Whether, DR has the potential to ameliorate DNA damage-driven stem cell exhaustion remains incompletely understood. In this study, we show that DR strongly extends the time to hair graying in response to γ-irradiation (ionizing radiation [IR])-induced DNA damage of C57BL/6 J mice. The study shows that DR prolongs resting phase of hair follicles. DR-mediated prolongation of hair follicle stem cell (HFSC) quiescence blocks hair growth and prevents the depletion of HFSCs and ckit+ melanoblasts in response to IR. However, prolongation of HFSC quiescence also correlates with a suppression of DNA repair and cannot prevent melanoblast loss and hair graying in the long run, when hair cycling is reinitiated even after extended periods of time. Altogether, these results support a model indicating that nutrient deprivation can delay but not heal DNA damage-driven extinction of melanoblasts by stalling HFSCs in a prolonged state of quiescence coupled with inhibition of DNA repair. Disconnecting these two types of responses to DR could have the potential to delay stem cell aging.

Time-Restricted Fasting Improves Liver Steatosis in Non-Alcoholic Fatty Liver Disease-A Single Blinded Crossover Trial

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is associated with visceral adiposity. We assessed the effectiveness of time-restricted fasting (TRF) for 16 h daily without calorie restrictions compared to standard care (SC; diet and lifestyle advice) in improving visceral adiposity and steatosis via controlled attenuation parameter (CAP).

METHODS

In a prospective single-blind randomized controlled trial, 32 participants with NAFLD were randomly assigned to TRF or SC for 12 weeks. The secondary endpoints were changes in liver stiffness, anthropometry, blood pressure, and other metabolic factors.

RESULTS

Twenty-eight participants completed the first arm of the study (TRF = 14, SC = 14), with 23 completing the crossover arm (TRF = 10, SC = 13). The baseline demographics were similar between the groups. Intermittent fasting caused a significant decrease in hepatic steatosis (p = 0.038), weight (p = 0.005), waist circumference (p = 0.001), and BMI (p = 0.005) compared to standard care. Intermittent fasting also resulted in additional within-group changes that were not seen in the standard care intervention.

CONCLUSION

TRF offers superior improvements in patients with NAFLD, improving steatosis, weight, and waist circumference despite a lack of change in overall caloric intake. Time-restricted fasting should be considered as a primary weight loss intervention in the context of NAFLD.

TRIAL REGISTRATION

ACTRN12613000935730.

Dietary outcomes of community-based CVD preventive interventions: a systematic review and meta-analysis

OBJECTIVE

We aimed to synthesise available evidence on the effects of community-based interventions in improving various dietary outcome measures.

DESIGN

Systematic review and meta-analysis.

SETTING

We searched databases including Medline, EMBASE, PSYCINFO, CINAHL and the Cochrane registry for studies reported between January 2000 and June 2022. The methodological quality of the included studies was evaluated using the Cochrane risk of bias tools for each study type. For some of the outcomes, we pooled the effect size using a random-effects meta-analysis.

PARTICIPANTS

A total of fifty-one studies, thirty-three randomised and eighteen non-randomised, involving 100 746 participants were included.

RESULTS

Overall, thirty-seven studies found a statistically significant difference in at least one dietary outcome measure favouring the intervention group, whereas fourteen studies found no statistically significant difference. Our meta-analyses indicated that, compared with controls, interventions were effective in decreasing daily energy intake (MJ/d) (mean difference (MD): -0·25; 95 % CI: -0·37, -0·14), fat % of energy (MD: -1·01; 95 % CI: -1·76, -0·25) and saturated fat % of energy (MD: -1·54; 95 % CI: -2·01, -1·07). Furthermore, the interventions were effective in improving fibre intake (g/d) (MD: 1·08; 95 % CI: 0·39, 1·77). Effective interventions use various strategies including tailored individual lifestyle coaching, health education, health promotion activities, community engagement activities and/or structural changes.

CONCLUSION

This review shows the potential of improving dietary patterns through community-based CVD preventive interventions. Thus, development and implementation of context-specific preventive interventions could help to minimise dietary risk factors, which in turn decrease morbidity and mortality due to CVD and other non-communicable diseases.

Longevity through diet restriction and immunity

The share of the population that is aging is growing rapidly. In an aging society, technologies and interventions that delay the aging process are of great interest. Dietary restriction (DR) is the most reproducible and effective nutritional intervention tested to date for delaying the aging process and prolonging the health span in animal models. Preventive effects of DR on age-related diseases have also been reported in human. In addition, highly conserved signaling pathways from small animal models to human mediate the effects of DR. Recent evidence has shown that the immune system is closely related to the effects of DR, and functions as a major mechanism of DR in healthy aging. This review discusses the effects of DR in delaying aging and preventing age-related diseases in animal, including human, and introduces the molecular mechanisms that mediate these effects. In addition, it reports scientific findings on the relationship between the immune system and DRinduced longevity. The review highlights the role of immunity as a potential mediator of the effects of DR on longevity, and provides insights into healthy aging in human. [BMB Reports 2023; 56(10): 537-544].

Association between Meal Frequency and Type 2 Diabetes Mellitus in Rural Adults: A Large-Scale Cross-Sectional Study

Diet frequency may potentially influence metabolic health. However, general population-based evidence on the association between meal frequency and type 2 diabetes mellitus (T2DM) remains limited and inconclusive. Thus, this study aimed to investigate the association between meal frequency and T2DM in resource limited area. A total of 29,405 qualified participants were enrolled from the Henan rural cohort study. Data on meal frequency were collected through a validated face-to-face questionnaire survey. Logistic regression models were utilized to explore the association between meal frequency and T2DM. Compared with 21 times per week meal frequency group, the adjusted odds ratios (ORs) and 95% confidence intervals (95%CIs) were 0.75 (0.58, 0.95) and 0.70 (0.54, 0.90) for 16–20 times/week group and 14–15 times/week group, respectively. For the analysis of the three meals, significant associations were only found between dinner frequency and T2DM. Compared with seven times per week dinner group, the ORs (95%CIs) were 0.66 (0.42, 0.99) and 0.51 (0.29, 0.82) for the group with three to six times/week and zero to two times/week. Reduced meal frequency, especially dinner frequency, was associated with lower prevalence of T2DM, which suggests that an appropriate reduction in meal frequency per week may have a role in decreasing the risk of T2DM.

Meal Skipping and Shorter Meal Intervals Are Associated with Increased Risk of All-Cause and Cardiovascular Disease Mortality among US Adults

BACKGROUND

Previous dietary studies and current dietary guidelines have mainly focused on dietary intake and food patterns. Little is known about the association between eating behaviors such as meal frequency, skipping and intervals, and mortality.

OBJECTIVE

The objective was to examine the associations of meal frequency, skipping, and intervals with all-cause and cardiovascular disease (CVD) mortality.

DESIGN

This was a prospective study.

PARTICIPANTS/SETTING

A total of 24,011 adults (aged ≥40 years) who participated in the National Health and Nutrition Examination Survey 1999-2014 were included in this study. Eating behaviors were assessed using 24-hour recall. Death and underlying causes of death were ascertained by linkage to death records through December 31, 2015.

MAIN OUTCOME MEASURES

The outcomes were all-cause and CVD mortality.

STATISTICAL ANALYSES PERFORMED

Multivariable Cox proportional hazards models were used to estimate adjusted hazard ratios (HRs) of all-cause and CVD mortality.

RESULTS

During 185,398 person-years of follow-up period, 4,175 deaths occurred, including 878 cardiovascular deaths. Most participants ate three meals per day. Compared with participants eating three meals per day, the multivariable-adjusted HRs for participants eating one meal per day were 1.30 (95% CI 1.03 to 1.64) for all-cause mortality, and 1.83 (95% CI 1.26 to 2.65) for CVD mortality. Participants who skipped breakfast have multivariable-adjusted HRs 1.40 (95% CI 1.09 to 1.78) for CVD mortality compared with those who did not. The multivariable-adjusted HRs for all-cause mortality were 1.12 (95% CI 1.01 to 1.24) for skipping lunch and 1.16 (95% CI 1.02 to 1.32) for skipping dinner compared with those who did not. Among participants eating three meals per day, the multivariable-adjusted HR for participants with an average interval of ≤4.5 hours in two adjacent meals was 1.17 (95% CI 1.04 to 1.32) for all-cause mortality, comparing with those having a meal interval of 4.6 to 5.5 hours.

CONCLUSIONS

In this large, prospective study of US adults aged 40 years or older, eating one meal per day was associated with an increased risk of all-cause and CVD mortality. Skipping breakfast was associated with increased risk of CVD mortality, whereas skipping lunch or dinner was associated with increased risk of all-cause mortality. Among participant with three meals per day, a meal interval of ≤4.5 hours in two adjacent meals was associated with higher all-cause mortality.

Nutritional strategies for intervention of diabetes and improvement of β-cell function

Diabetes mellitus, especially Type 2 diabetes (T2D), is caused by multiple factors including genetics, diets, and lifestyles. Diabetes is a chronic condition and is among the top 10 causes of death globally. Nutritional intervention is one of the most important and effective strategies for T2D management. It is well known that most of intervention strategies can lower blood glucose level and improve insulin sensitivity in peripheral tissues. However, the regulation of pancreatic β cells by dietary intervention is not well characterized. In this review, we summarized some of the commonly used nutritional methods for diabetes intervention. We then discussed the effects and the underlying mechanisms of nutritional intervention in improving the cell mass and function of pancreatic islet β cells. With emerging intervention strategies and in-depth investigation, we are expecting to have a better understanding about the effectiveness of dietary interventions in ameliorating T2D in the future.

Feasibility and acceptability of time-restricted eating in a group of adults with multiple sclerosis

Introduction

Intermittent fasting (IF) has become a popular dietary pattern for adults with multiple sclerosis (MS), and initial studies in animal models and human trials indicate promising results for improving symptoms and slowing disease progression. Most studies published to date have focused on alternate day fasting or fasting mimicking diets including a 5:2 pattern, in which participants greatly restrict calorie intake on two non-consecutive days and eat regularly on other days; however, time restricted eating (TRE) may be equally effective for improving symptoms and may lead to better long term adherence due to its focus only on the time of day in which calories are consumed with no restriction on number of calories or types of food consumed.

Methods

The purpose of this pilot study was to determine the feasibility and acceptability of a TRE intervention in adults with relapsing remitting MS (RRMS). Participants (n = 12) were instructed to eat all food within an 8-h window every day and fast the remaining 16 h for 8 weeks.

Results

The eating pattern was determined to be feasible based on retention rates (n = 11; 92%) and acceptable based on participant feedback.

Discussion

Exploratory results of changes in cognition, pain, and fatigue, indicate that further study of TRE in this population is warranted.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT04389970; NCT04389970.

Healthy lifestyles and wellbeing reduce neuroinflammation and prevent neurodegenerative and psychiatric disorders

Since the mid-20th century, Western societies have considered productivity and economic outcomes are more important than focusing on people's health and wellbeing. This focus has created lifestyles with high stress levels, associated with overconsumption of unhealthy foods and little exercise, which negatively affect people's lives, and subsequently lead to the development of pathologies, including neurodegenerative and psychiatric disorders. Prioritizing a healthy lifestyle to maintain wellbeing may slow the onset or reduce the severity of pathologies. It is a win-win for everyone; for societies and for individuals. A balanced lifestyle is increasingly being adopted globally, with many doctors encouraging meditation and prescribing non-pharmaceutical interventions to treat depression. In psychiatric and neurodegenerative disorders, the inflammatory response system of the brain (neuroinflammation) is activated. Many risks factors are now known to be linked to neuroinflammation such as stress, pollution, and a high saturated and trans fat diet. On the other hand, many studies have linked healthy habits and anti-inflammatory products with lower levels of neuroinflammation and a reduced risk of neurodegenerative and psychiatric disorders. Sharing risk and protective factors is critical so that individuals can make informed choices that promote positive aging throughout their lifespan. Most strategies to manage neurodegenerative diseases are palliative because neurodegeneration has been progressing silently for decades before symptoms appear. Here, we focus on preventing neurodegenerative diseases by adopting an integrated "healthy" lifestyle approach. This review summarizes the role of neuroinflammation on risk and protective factors of neurodegenerative and psychiatric disorders.

Time-restricted feeding and cognitive function in sedentary and physically active elderly individuals: Ramadan diurnal intermittent fasting as a model

Objectives

This study aimed to investigate the effects of Ramadan diurnal intermittent fasting (RDIF) on cognitive performance, sleep quality, daytime sleepiness, and insomnia in physically active and sedentary elderly individuals.

Methods

A total of 58 participants (62.93 ± 3.99 years) were assigned to one of the following two groups: a sedentary group (control group) who observed Ramadan (n = 32) and a physically active group (n = 26) who continued to train while observing Ramadan. Participants were assessed 2 weeks before Ramadan and during the fourth week of Ramadan. On each occasion, participants completed a digital assessment of their cognitive performance and responded to the Pittsburgh sleep quality index (PSQI), the insomnia severity index (ISI) and the Epworth sleepiness scale (ESS) questionnaires to assess sleep parameters.

Results

Compared to before Ramadan, performance in executive function (p = 0.035), attention (p = 0.005), inhibition (p = 0.02), associative memory (p = 0.041), and recognition memory (p = 0.025) increased significantly during Ramadan in the physically active group. For the sedentary group, associative learning performance decreased (p = 0.041), whilst performances in the remaining domains remained unchanged during Ramadan. Global PSQI, ISI, and ESS scores indicated both groups suffered from poor sleep quality and excessive daytime sleepiness, with significantly higher negative effects of RDIF observed in the sedentary group.

Conclusion

Older adults who continue to train at least three times per week during Ramadan may improve their cognitive performance, despite the impairment of sleep quality. Future studies in older adults during Ramadan including objective measures of sleep (e.g., polysomnography, actigraphy) and brain function (e.g., functional magnetic resonance imaging) are warranted.

Long-Term Calorie Restriction Alters Anxiety-like Behaviour and the Brain and Adrenal Gland Transcriptomes of the Ageing Male Rat

Further examination of the molecular regulators of long-term calorie restriction (CR), reported to have an anxiolytic effect, may highlight novel therapeutic targets for anxiety disorders. Here, adult male Hooded Wistar rats were exposed to a 25% CR whilst anxiety-like behaviour was assessed at 6-, 12-, and 18-months of age via the elevated plus maze, open field, and acoustic startle tests. Next-generation sequencing was then used to measure transcriptome-wide gene expression in the hypothalamus, amygdala, pituitary, and adrenal glands. Results showed an anxiolytic behavioural profile across early, middle, and late adulthood by CR, with the strongest effects noted at 6-months. Transcriptomic analysis by seven attribute weighting algorithms, including Info Gain Ratio, Rule, Chi Squared, Gini Index, Uncertainty, Relief, and Info Gain, led to the development of a signature of long-term CR, independent of region. Complement C1q A chain (C1qa), an extracellular protein, expression was significantly decreased by CR in most regions examined. Furthermore, text mining highlighted the positive involvement of C1qa in anxiety, depression, neurodegeneration, stress, and ageing, collectively identifying a suitable biomarker candidate for CR. Overall, the current study identified anxiety-related phenotypic changes and a novel transcriptome signature of long-term CR, indicating potential therapeutic targets for anxiety, depression, and neurodegeneration.

Fasting in mood disorders and its potential therapeutic aspects -narrative review

Introduction: Fasting is defined as a period of voluntary abstinence from eating food for religious, therapeutic or political reasons, which is associated with a reduction in the supply of sources (kilocalories) to the body. There are different types of fasting, including short, long or intermittent fasting. It has been shown that the use of different types of fasting can influence the occurrence of mood disorders. The aim of this review was to search for the relationship between the use of fasting and mood disorders and its potential use as a therapeutic method.

Material and method: The available literature was reviewed by searching the PubMed and Google Scholar databases using the following keywords: fasting, intermittent fasting, mood disorders, depression, Ramadan, for studies listed from database inception to November 2021.

Results: A review of the collected scientific articles indicates that the dietary restrictions, including both daily restriction of caloric consumption and the use of intermittent fasting (IF), has potentially numerous health benefits in the co-treatment of mental diseases. However, due to conflicting results, further clinical trials in mentally ill people should be conducted. It is worth remembering that among patients with mental illnesses there are somatically ill. IF in these people may require additional nutritional modifications or discontinuation of therapy.

Conclusions: Dietary restriction and fasting are promising methods in co-therapy of mood disorders treatment. However, implementing therapy needs earlier individual evaluation of their benefits and risk, the same as patient’s feasibility of implementing this type of intervention.

The Effect of Fasting on Human Metabolism and Psychological Health

Fasting is a prevalent approach to weight loss and is a feasible method for treating some diseases, such as type 2 diabetes. Meanwhile, the effects of intermittent fasting on health, aging, and disease process are hot issues and are of concern by researchers of multiple areas, even the public. This article introduces the effects of fasting on human lipid metabolism, glucose metabolism, protein metabolism, and neuroendocrine metabolism; demonstrates the metabolic conversion caused by fasting; and describes the effects of fasting on human psychological health, the relationship between mood regulation and glucose, and the emotional enhancing effect induced by fasting.

Visual processing and BDNF levels in first-episode schizophrenia

Previous studies have shown that patients diagnosed with schizophrenia (SCZ) have deficits in early visual processing, namely contrast processing. The brain-derived neurotropic factor (BDNF) is an important measure to investigate neuroplasticity in some visual functions like visual perception. In this study, we investigated the relationship between visual processing and BDNF levels in first-episode SCZ patients. Thirty-nine healthy controls and 43 first-episode SCZ patients were enrolled. Contrast sensitivity measurements were conducted using low, mid- and high spatial frequencies. First-episode SCZ patients had higher contrast sensitivity than healthy controls for all frequencies, except for the middle spatial frequency. Negative correlations were found between BDNF, contrast sensitivity and clinical variables, mostly for middle and high spatial frequencies among females. Our results provide support for (i) the association of SCZ with alterations of magno- and parvocellular pathway functioning and (ii) decreased BDNF levels in first-episode SCZ patients. This study highlights the importance of using biomarkers along with other measures to investigate visual processing in SCZ and other disorders.

Time-Restricted Feeding and Metabolic Outcomes in a Cohort of Italian Adults

BACKGROUND

research exploring the effects of food timing and frequency on health and disease is currently ongoing. While there is an increasing body of scientific literature showing the potential health benefits of intermittent fasting (IF) in laboratory settings and in animals, studies regarding IF on humans are limited. Therefore, the objective of this research was to evaluate the relationship between the feeding/fasting time window and metabolic outcomes among adult individuals.

METHODS

dietary and demographic data of 1936 adult subjects living in the south of Italy were examined. Food frequency questionnaires (FFQ) were administered to determine the period of time between the first and the last meal of a typical day. Subjects were then divided into those with a time feeding window lasting more than 10 h, within 8 h (TRF-8) and within 10 h.

RESULTS

after adjustment for potential confounding factors related to eating habits (such as adherence to the Mediterranean diet, having breakfast/dinner), TRF-10 was inversely associated with being overweight/obese (OR = 0.05, 95% CI: 0.01, 0.07), hypertension (OR = 0.24, 95% CI: 0.13, 0.45), and dyslipidemias (OR = 0.26, 95% CI: 0.10, 0.63), while TRF-8 only with being overweight/obese (OR = 0.08, 95% CI: 0.04, 0.15) and hypertension (OR = 0.33, 95% CI: 0.17, 0.60). No associations were found with type-2 diabetes.

CONCLUSIONS

individuals with a restricted feeding time window were less likely to be overweight, obese and hypertensive. Further studies are needed to clearly validate the results of the present study.

The Neuroimmune Role of Intestinal Microbiota in the Pathogenesis of Cardiovascular Disease

Currently, a bidirectional relationship between the gut microbiota and the nervous system, which is considered as microbiota-gut-brain axis, is being actively studied. This axis is believed to be a key mechanism in the formation of somatovisceral functions in the human body. The gut microbiota determines the level of activation of the hypothalamic-pituitary system. In particular, the intestinal microbiota is an important source of neuroimmune mediators in the pathogenesis of cardiovascular disease. This review reflects the current state of publications in PubMed and Scopus databases until December 2020 on the mechanisms of formation and participation of neuroimmune mediators associated with gut microbiota in the development of cardiovascular disease.

Effects of caloric restriction on the antagonistic and integrative hallmarks of aging

Aging is a significant risk factor for cognitive decline associated with neurodegenerative diseases, which makes understanding what promotes 'healthy brain aging' very important. Studies suggest that caloric restriction (CR) is a non-genetic intervention that reliably extends life- and healthspan. Here, we review the CR literature related to both the subject of aging and alterations in cell cycle machinery, especially surrounding the regulation of the E2F/DP1 complex, to elucidate the cellular protection mechanisms in the brain induced via dietary applications. The alterations extending lifespan via CR appear to exert their effects by promoting survival of individual cells, downregulating cell proliferation, and inducing stem cell quiescence, which results in keeping the stem cell reserve for extreme needs. This survival instinct of cells is believed to cause some molecular adaptations for their maintenance of the system. Avoiding energy waste of proliferation machinery promotes the long term survival of the individual cells and this is due to adaptations to the limited nutrient supply in the environment. Such a protective mechanism induced by diet could be promoted via the downregulation of crucial cell cycle-related transcription activators. This review article aims to bring attention to the importance of molecular adaptations induced by diet that promote healthy brain aging. It will provide insights into alternative targets for new treatments or neuroprotective approaches against neurodegenerative pathophysiologies.

The feeding microstructure of male and female mice

The feeding pattern and control of energy intake in mice housed in groups are poorly understood. Here, we determined and quantified the normal feeding microstructure of social male and female mice of the C57BL/6J genetic background fed a chow diet. Mice at 10w, 20w and 30w of age showed the expected increase in lean and fat mass, being the latter more pronounced and variable in males than in females. Under ad libitum conditions, 20w and 30w old females housed in groups showed significantly increased daily energy intake when adjusted to body weight relative to age-matched males. This was the combined result of small increases in energy intake during the nocturnal and diurnal photoperiods of the day without major changes in the circadian pattern of energy intake or spontaneous ambulatory activity. The analysis of the feeding microstructure suggests sex- and age-related contributions of meal size, meal frequency and intermeal interval to the control of energy intake under stable energy balance, but not under negative energy balance imposed by prolonged fasting. During the night, 10-20w old females ate less frequently bigger meals and spent more time eating them resulting in reduced net energy intake relative to age-matched males. In addition, male and female mice at all ages tested significantly shortened the intermeal interval during the first hours of re-feeding in response to fasting without affecting meal size. Further, 20-30w old males lengthened their intermeal interval as re-feeding time increased to reach fed-levels faster than age-matched females. Collectively, our results suggest that the physiological mechanisms controlling meal size (satiation) and the non-eating time spent between meals (satiety) during stable or negative energy balance are regulated in a sex- and age-dependent manner in social mice.

Calorie restriction for enhanced longevity: The role of novel dietary strategies in the present obesogenic environment

Calorie restriction (CR) is a potent modulator of longevity in multiple species. A growing body of evidence shows that sustained periods of CR without malnutrition improves risk factors involved in the pathophysiology of type 2 diabetes, cardiovascular diseases, cancer, and neurological disorders in humans. Innovative dietary strategies such as intermittent fasting and protein restriction have recently emerged as alternative approaches that improve markers of aging. Some of these newer strategies might provide benefits for healthy aging with little to no CR and therefore, compared to traditional CR, may be easier to follow. Further to providing an update of CR studies in humans, the present narrative review appraises the influence of these contemporary dietary strategies on mechanisms posited to drive CR-induced longevity in humans, including those involving energy metabolism, oxidative damage, inflammation, glucose homeostasis, and functional changes in the neuroendocrine systems. The review also discusses the utilization of these diets for populations in the current obesogenic environment, and comments on whether current research can inform an optimal diet that attenuates aging, can be easily followed, and promises to improve longevity in humans.

Prevention of dementia in an ageing world: Evidence and biological rationale

As the population ages, the number of people with dementia is expected to increase in the coming decades, with consequences at the societal and individual levels. In this narrative review, we provide a summary of the scientific evidence concerning dementia prevention, with a focus on the following three strategies: 1) Targeting the body to protect the brain, including prevention and treatment of cardiovascular morbidity; 2) Compensatory interventions to counteract brain ageing, including education and life-long engagement in cognitively and socially stimulating activities; and 3) Lifespan health promotion, such as a physically active lifestyle, smoking cessation, and a healthy and balanced diet. Next, we consider the biological mechanisms by which these strategies may act by taking into account the main pathways implicated in the development and progression of dementia: neurodegeneration, brain resilience, vascular damage, neuroinflammation, and oxidative stress. Based on the current evidence, and in line with the declining trends of dementia incidence in high-income countries, we conclude that timely multidomain preventive actions are promising strategies to reduce the dementia epidemic worldwide. There is still a considerable gap between the epidemiological evidence and its underlying biological mechanisms. Filling this gap will be crucial to move forward in dementia prevention worldwide.

An eating pattern characterised by skipped or delayed breakfast is associated with mood disorders among an Australian adult cohort

BACKGROUND

Meal timing may influence food choices, neurobiology and psychological states. Our exploratory study examined if time-of-day eating patterns were associated with mood disorders among adults.

METHODS

During 2004-2006 (age 26-36 years) and 2009-2011 (follow-up, age 31-41 years), N = 1304 participants reported 24-h food and beverage intake. Time-of-day eating patterns were derived by principal components analysis. At follow-up, the Composite International Diagnostic Interview measured lifetime mood disorder. Log binomial and adjacent categories log-link regression were used to examine bidirectional associations between eating patterns and mood disorder. Covariates included sex, age, marital status, social support, education, work schedule, body mass index and smoking.

RESULTS

Three patterns were derived at each time-point: Grazing (intake spread across the day), Traditional (highest intakes reflected breakfast, lunch and dinner), and Late (skipped/delayed breakfast with higher evening intakes). Compared to those in the lowest third of the respective pattern at baseline and follow-up, during the 5-year follow-up, those in the highest third of the Late pattern at both time-points had a higher prevalence of mood disorder [prevalence ratio (PR) = 2.04; 95% confidence interval (CI) 1.20-3.48], and those in the highest third of the Traditional pattern at both time-points had a lower prevalence of first onset mood disorder (PR = 0.31; 95% CI 0.11-0.87). Participants who experienced a mood disorder during follow-up had a 1.07 higher relative risk of being in a higher Late pattern score category at follow-up than those without mood disorder (95% CI 1.00-1.14).

CONCLUSIONS

Non-traditional eating patterns, particularly skipped or delayed breakfast, may be associated with mood disorders.

Expression pattern of brain-derived neurotrophic factor and its associated receptors: Implications for exogenous neurotrophin application

The application of neurotrophins such as brain-derived neurotrophic factor (BDNF) is a promising pharmacological approach in cochlear implant research. Several in vitro and in vivo studies demonstrated that treatment with neurotrophins support the spiral ganglion neuron (SGN) survival and the synapses. Of the more than 40 companies that are working in the field of inner ear therapeutics, only one company is currently advancing BDNF towards clinical translation. Thus, there are no approved clinical therapies with neurotrophins, their precursors or neurotrophin-like substances. For a better understanding of the mechanisms of BDNF in the inner ear, we analysed the expression of mature BDNF (mBDNF), its pro-form proBDNF and their respective receptors the low affinity p75 neurotrophin receptor (p75NTR) and the neurotrophic receptor tyrosine kinase 2 (NTRK2). In the adult murine inner ear, mBDNF is expressed in the inner and outer hair cells (IHC and OHC) of the organ of Corti and in the spiral ganglion of the Rosenthal's canal, whereas proBDNF is only detected in the supporting cells below the OHC. The corresponding receptors NTRK2 and p75NTR are expressed in the spiral ganglion whereof p75NTR is stronger expressed. For more insights in the effects of mBDNF and proBDNF on inner ear specific cells, we treated primary dissociated SGN with different concentrations of mBDNF and proBDNF alone and in combination. Interestingly, treatment with proBDNF is not toxic for SGN but simultaneously not protective. However, combined treatment of mBDNF and proBDNF maintained and perhaps slightly increased the protective effect of mBDNF. Thus, the mixture of mBDNF and proBDNF could be the new direction for the development of BDNF-based therapeutics in cochlear implantation and could represent more precisely the natural environment.

4E-BP1 Protects Neurons from Misfolded Protein Stress and Parkinson's Disease Toxicity by Inducing the Mitochondrial Unfolded Protein Response

Decline of protein quality control in neurons contributes to age-related neurodegenerative disorders caused by misfolded proteins. 4E-BP1 is a key node in the regulation of protein synthesis, as activated 4E-BP1 represses global protein translation. Overexpression of 4E-BP1 mediates the benefits of dietary restriction and can counter metabolic stress, and 4E-BP1 disinhibition on mTORC1 repression may be neuroprotective; however, whether 4E-BP1 overexpression is neuroprotective in mammalian neurons is yet to be fully explored. To address this question, we generated 4E-BP1-overexpressing transgenic mice and confirmed marked reductions in protein translation in 4E-BP1-overexpressing primary neurons. After documenting that 4E-BP1-overexpressing neurons are resistant to proteotoxic stress elicited by brefeldin A treatment, we exposed primary neurons to three different Parkinson's disease (PD)-linked toxins (rotenone, maneb, or paraquat) and documented significant protection in neurons from newborn male and female 4E-BP1-OE transgenic mice. We observed 4E-BP1-dependent upregulation of genes encoding proteins that comprise the mitochondrial unfolded protein response, and noted 4E-BP1 overexpression required activation of the mitochondrial unfolded protein response for neuroprotection against rotenone toxicity. We also tested whether 4E-BP1 could prevent α-synuclein neurotoxicity by treating 4E-BP1-overexpressing primary neurons with α-synuclein preformed fibrils, and we observed marked reductions in α-synuclein aggregation and neurotoxicity, thus validating that 4E-BP1 is a powerful suppressor of PD-linked pathogenic insults. Our results indicate that increasing 4E-BP1 expression or enhancing 4E-BP1 activation can robustly induce the mitochondrial unfolded protein response and thus could be an appealing strategy for treating a variety of neurodegenerative diseases, including especially PD.SIGNIFICANCE STATEMENT In neurodegenerative disease, misfolded proteins accumulate and overwhelm normal systems of homeostasis and quality control. One mechanism for improving protein quality control is to reduce protein translation. Here we investigated whether neuronal overexpression of 4E-BP1, a key repressor of protein translation, can protect against misfolded protein stress and toxicities linked to Parkinson's disease, and found that 4E-BP1 overexpression prevented cell death in neurons treated with brefeldin A, rotenone, maneb, paraquat, or preformed fibrils of α-synuclein. When we sought the basis for 4E-BP1 neuroprotection, we discovered that 4E-BP1 activation promoted the mitochondrial unfolded protein response. Our findings highlight 4E-BP1 as a therapeutic target in neurodegenerative disease and underscore the importance of the mitochondrial unfolded protein response in neuroprotection against various insults.

Restoring aged stem cell functionality: Current progress and future directions

Stem cell dysfunction is a hallmark of aging, associated with the decline of physical and cognitive abilities of humans and other mammals [Cell 2013;153:1194]. Therefore, it has become an active area of research within the aging and stem cell fields, and various techniques have been employed to mitigate the decline of stem cell function both in vitro and in vivo. While some techniques developed in model organisms are not directly translatable to humans, others show promise in becoming clinically relevant to delay or even mitigate negative phenotypes associated with aging. This review focuses on diet, treatment, and small molecule interventions that provide evidence of functional improvement in at least one type of aged adult stem cell.

Short-term calorie restriction enhances DNA repair by non-homologous end joining in mice

Calorie restriction (CR) improves health, reduces cancer incidence and extends lifespan in multiple organisms including mice. CR was shown to enhance base excision repair and nucleotide excision repair pathways of DNA repair, however, whether CR improves repair of DNA double-strand breaks has not been examined in in vivo system. Here we utilize non-homologous end joining (NHEJ) reporter mice to show that short-term CR strongly enhances DNA repair by NHEJ, which is associated with elevated levels of DNA-PK and SIRT6.

Intermittent Fasting: Physiological Implications on Outcomes in Mice and Men

Intermittent fasting (IF) is a widely practiced dietary method that encompasses periodic restriction of food consumption. Due to its protective benefits against metabolic diseases, aging, and cardiovascular and neurodegenerative diseases, IF continues to gain attention as a preventative and therapeutic intervention to counteract these chronic diseases. Although numerous animal studies have reported positive health benefits of IF, its feasibility and efficacy in clinical settings remain controversial. Importantly, since dietary interventions such as IF have systemic effects, thoroughly investigating the tissue-specific changes in animal models is crucial to identify IF's mechanism and evaluate its potential adverse effects in humans. As such, we will review and compare the outcomes and underlying mechanisms of IF in both animal and human studies. Moreover, the limitations of IF and inconsistencies between preclinical and clinical studies will be discussed to provide insight into the gaps between translating research from bench to bedside.

Mechanisms of Lifespan Regulation by Calorie Restriction and Intermittent Fasting in Model Organisms

Genetic and pharmacological interventions have successfully extended healthspan and lifespan in animals, but their genetic interventions are not appropriate options for human applications and pharmacological intervention needs more solid clinical evidence. Consequently, dietary manipulations are the only practical and probable strategies to promote health and longevity in humans. Caloric restriction (CR), reduction of calorie intake to a level that does not compromise overall health, has been considered as being one of the most promising dietary interventions to extend lifespan in humans. Although it is straightforward, continuous reduction of calorie or food intake is not easy to practice in real lives of humans. Recently, fasting-related interventions such as intermittent fasting (IF) and time-restricted feeding (TRF) have emerged as alternatives of CR. Here, we review the history of CR and fasting-related strategies in animal models, discuss the molecular mechanisms underlying these interventions, and propose future directions that can fill the missing gaps in the current understanding of these dietary interventions. CR and fasting appear to extend lifespan by both partially overlapping common mechanisms such as the target of rapamycin (TOR) pathway and circadian clock, and distinct independent mechanisms that remain to be discovered. We propose that a systems approach combining global transcriptomic, metabolomic, and proteomic analyses followed by genetic perturbation studies targeting multiple candidate pathways will allow us to better understand how CR and fasting interact with each other to promote longevity.

The Effects of Different Feeding Routines on Welfare in Laboratory Mice

The accepted norm in most laboratories around the globe is feeding laboratory mice an ad libitum diet, although several health impairments are well-established. In contrast, reducing the animals' body weight by feeding them less food once per day (referred to as 24 h schedule) has been shown to enhance life span and reduce disease susceptibility. Against this background, this study aimed at systematically investigating the effects of different feeding routines. Therefore, three feeding routines were compared to the standard ad libitum feeding and effects on body weight development and welfare were investigated in male C57BL/6J mice. In particular, a 24 h schedule group, an AUTO group, characterized by an automated supply of small pieces of food all over the day, and a 4 h removal group, characterized by daily removal of food for 4 h, were studied. While the removal of food for 4 h per day did not lead to a reduction of body weight, and hence is unlikely to prevent negative effects of overfeeding, both the 24 h schedule group and the AUTO group led to the aspired body weight reduction. In the AUTO group, however, higher levels of corticosterone metabolites and stereotypies were observed, implying a rather negative impact on welfare. By contrast, no distinct negative effects of a 24 h schedule were found. Studies like this underline the general need for evidence-based severity assessments of any procedure involving living animals.

Higher eating frequency, but not skipping breakfast, is associated with higher odds of abdominal obesity in adults living in Puerto Rico

Puerto Ricans have a high prevalence of obesity, yet little information is available regarding its association with eating patterns in this population. We hypothesized that higher eating frequency and skipping breakfast would be associated with increased odds of abdominal obesity among adults living in Puerto Rico (PR). In a cross-sectional study of adults living in PR aged 30-75 years (N = 310), participants reported their frequency of eating meals per day including snacks and breakfast. Trained interviewers measured waist (WC) and hip circumferences. We calculated the waist-to-hip ratio (WHR) dividing the waist by the hip measurement. Abdominal obesity was defined as either high WC (men ≥94 cm; women ≥80 cm) or high WHR (men ≥0.90; women ≥0.85). We used logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) to assess the association of eating frequency (≤1.5; 1.5-3; ≥3 times/day) and breakfast consumption (vs none) with abdominal obesity. Models were adjusted for age, sex, income, smoking, physical activity, TV watching, energy intake, diet quality, and eating frequency (only for breakfast consumption). Most participants consumed breakfast (70%), ate 1.5-3 times/d (47%), and had high WC (75%) and WHR (77%). Participants who ate 1.5-3 (OR: 2.75, 95% CI: 1.23-6.15) and ≥3 times/day (OR: 2.88; 95% CI: 1.14-7.31) were more likely to have high WC compared with participants who ate ≤1.5 times/d (P trend = .04). Breakfast consumption was not associated with abdominal obesity. In conclusion, higher eating frequency, but not skipping breakfast, is associated with abdominal obesity among adults in PR. Consuming less frequent meals may help prevent abdominal obesity in this population.

Intermittent Fasting Reverses an Advanced Form of Cardiomyopathy

See Article by Ma et al

Effects of Different Dietary Protocols on General Activity and Frailty of Male Wistar Rats During Aging

Dietary restriction (DR) is an important experimental paradigm for lifespan and healthspan extension, but its specific contribution regarding the type, onset, and duration are still debatable. This study was designed to examine the impact of different dietary protocols by assessing the behavioral changes during aging. We exposed male Wistar rats of various age to ad libitum (AL) or DR (60 per cent of AL daily intake) feeding regimens with different onsets. The impact of DR on locomotor activity, memory, and learning was examined in 12-, 18-, and 24-month-old treated animals and controls using open field and Y-maze tests. We have also evaluated the effects of different DR's through the quantification of animal frailty, using behavioral data to create the frailty score. Our results indicated that DR improves general animal activity and spatial memory and decreases frailty with the effect being highly dependent on DR duration and onset. Notably, life-long restriction started at young age had the most profound effect. In contrast, shorter duration and later onset of restricted diet had significantly lower or no impact on animal's behavior and frailty. This study signifies the importance of DR starting point and duration as critical determinants of DR effects on healthspan.

Dietary Behaviour Is Associated with Cardiometabolic and Psychological Risk Indicators in Female Hospital Nurses-A Post-Hoc, Cross-Sectional Study

Unfavourable dietary behaviours of female nurses, especially among shift-working nurses, including high snacking frequency, short fasting period and large day-to-day energy intake variability may be linked with adverse health. In this study we: (1) examined the relationship between dietary behaviour and cardiometabolic and psychological health in female nurses; and, (2) compared dietary behaviour, cardiometabolic and psychological health between shift-working and non-shift-working female nurses. A total of 73 nurses had their cardiometabolic health indicators evaluated and completed psychological health questionnaires; 55 completed a 3-day dietary log. Associations between dietary behaviour and health measures were examined using Spearman's partial correlation analysis. Analysis of covariance (ANCOVA) was used to compare dietary behaviour and health indicators between shift- and non-shift-working nurses. The majority of snacks consumed by nurses (70%) were unhealthy snacks (e.g., chocolate and chips), and higher snacking frequency was associated with greater percent body fat (r(50) = 0.287, p = 0.039), and worse mood-tension (r(48) = 0.327, p = 0.021) and anger-hostility (r(48) = 0.289, p = 0.042) scores. Day-to-day energy intake variability was positively associated with body mass index (BMI, r(50) = 0.356, p = 0.010) and waist circumference (r(50) = 0.283, p = 0.042). Shift-working nurses exhibited shorter fasting duration, larger day-to-day energy intake variability and higher total mood disturbance score when compared to their non-shift-working colleagues (all p < 0.05). The results of the present study suggested that addressing dietary behaviours may improve the cardiometabolic and psychological health of female nurses. Shift-working nurses may require a more specific dietary program to improve their psychological health.

Periodic dietary restriction ameliorates amyloid pathology and cognitive impairment in PDAPP-J20 mice: Potential implication of glial autophagy

Dietary restriction promotes cell regeneration and stress resistance in multiple models of human diseases. One of the conditions that could potentially benefit from this strategy is Alzheimer's disease, a chronic, progressive and prevalent neurodegenerative disease. Although there are no effective pharmacological treatments for this pathology, lifestyle interventions could play therapeutic roles. Our objectives were 1) to evaluate the effects of dietary restriction on cognition, hippocampal amyloid deposition, adult neurogenesis and glial reactivity and autophagy in a mouse model of familial Alzheimer's disease, and 2) to analyze the role of glial cells mediating the effects of nutrient restriction in an in vitro model. Therefore, we established a periodic dietary restriction protocol in adult female PDAPP-J20 transgenic mice for 6 weeks. We found that dietary restriction, not involving overall caloric restriction, attenuated cognitive deficits, amyloid pathology and microglial reactivity in transgenic mice when compared with ad libitum-fed transgenic animals. Also, transgenic mice showed an increase in the astroglial positive signal for LC3, an autophagy-associated protein. In parallel, hippocampal adult neurogenesis was decreased in transgenic mice whereas dietary-restricted transgenic mice showed a neurogenic status similar to controls. In vitro experiments showed that nutrient restriction decreased astroglial and, indirectly, microglial NFκB activation in response to amyloid β peptides. Furthermore, nutrient restriction was able to preserve astroglial autophagic flux and to decrease intracellular amyloid after exposure to amyloid β peptides. Our results suggest neuroprotective effects of nutrient restriction in Alzheimer's disease, with modulation of glial activation and autophagy being potentially involved pathways.

Toxin-induced hormesis may restrain aging

Mild environmental stress might have beneficial effects in aging by activating maintenance and repair processes in cells and organs. These beneficial stress effects fit to the concept of hormesis. Prominent stressors acting in a hormetic way are physical exercises, fasting, cold and heat. This review will introduce some toxins, which have been found to induce hormetic responses in animal models of aging research. To highlight the molecular signature of these hormetic effects we will depict signaling pathways affected by low doses of toxins on cellular and organismic level. As prominent examples for signaling pathways involved in both aging processes as well as toxin responses, PI3K/Akt/mTOR- and AMPK-signal transduction will be described in more detail. Due to the striking overlap of signaling pathways mediating toxin induced responses and aging processes we propose considering the ability of low doses of toxins to slow down the rate of aging.

Brain-Derived Neurotrophic Factor in Patients With Age-Related Macular Degeneration and Its Correlation With Retinal Layer Thicknesses

Purpose

To determine brain-derived neurotrophic factor (BDNF) levels in serum and aqueous humor (AH) and to assess the relationship between BDNF levels and retinal layer thicknesses in age-related macular degeneration (AMD).

Methods

A total of 48 AMD patients (AMD group) that was composed of twenty-three nonexudative and 25 exudative patients and 26 control subjects (control group) were included in the study. Serum and AH BDNF levels were assessed by ELISA method. Retinal layer thicknesses were calculated by segmentation analysis of optical coherence tomography.

Results

The mean BDNF levels in AH were found to be significantly lower in both the nonexudative and exudative AMD groups than in the control group (P = 0.003 and P < 0.001, respectively). Optical coherence tomography segmentation analysis revealed that the total average retina pigment epithelium thickness was statistically significantly thinner in the nonexudative AMD group compared with the exudative AMD and control groups (P = 0.001 and P = 0.040, respectively). The total average outer nuclear layer (ONL) thicknesses of nonexudative and exudative AMD cases were reduced compared to control group; however, the decrement was statistically significant only in the nonexudative AMD group (P = 0.009). In the correlation analysis of BDNF levels with retinal layer thicknesses, statistically significant correlations exist between BDNF levels of AH with ONL thicknesses in cases of AMD and with retina pigment epithelium thicknesses in the nonexudative AMD group.

Conclusions

BDNF concentrations in AH decreased in the AMD group and this decrease correlates with outer retinal layer thicknesses. Low BDNF levels detected in the AMD group may be insufficient to protect the photoreceptors, resulting in thinning of ONL.

The association of BDNF gene polymorphism with cognitive impairment in insomnia patients

BACKGROUND

Reductions in BDNF activity have shown associations with depressed mood. Other evidence has demonstrated that the BDNF Val66Met polymorphism (rs6265) appears to reduce neural plasticity. A limited number of studies have investigated the influence of these genetic polymorphisms in insomnia. The present study sought to confirm the presence of associations between BDNF Val66Met polymorphism (rs6265) occurrence in normal sleepers and those with insomnia.

METHOD

The study subjects consisted of a patient group (n = 199) complaining of insomnia and a control group (n = 51). Each subject was clinically interviewed using questions taken from the Brief Insomnia Questionnaire. After the interview, the subjects were asked to complete the Insomnia Severity Index, The Hamilton Depression Rating Scale, and the Montreal Cognitive Assessment Test. An overnight polysomnography test was also administered. Blood samples were collected for genetic study.

RESULTS

The insomnia patients showed a greater prevalence of heterozygous (A/G) VAL/MET polymorphism than the normal controls (p = ≤ 0.0001). This finding confirmed that this genetic polymorphism, which impairs BDNF activity, is an important correlate of disturbed sleep. Further, the finding of significantly greater (p = ≤ 0.0001) depression scores among the insomnia group suggested that BDNF is an important factor in the development of depressive symptoms.

CLINICAL IMPLICATIONS

The results of the present study indicate that BDNF gene polymorphism plays a prominent role in the variation of symptoms among insomnia patients and, further, that this polymorphism is strongly related to the severity of depression.

New approach to peripheral nerve injury: nutritional therapy

Purpose of review: There is no review in the literature on the effect of nutrition-related factors on peripheral nerve injuries. Therefore, it is aimed to evaluate the effect of nutritional factors on nerve injuries in this compilation. Recent findings: Although there are several fundamental mechanisms by which nutrients and nutritional factors influence individuals, their exact impacts on neurogenesis have not been clearly identified. Recently, some studies showed that some nutrients have an important role in nerve injuries due to their neuroprotective properties. In addition to surgical treatment, in peripheral nerve injuries, these nutrients also may play a role in preserving nerve function and health, as well as in the recovery of an injured nerve tissue. Omega 3 and omega 6 fatty acids, group B vitamins, antioxidants, several minerals, phenolic compounds, and alpha lipoic acid are thought to have impacts on the nervous system. In addition to all of these, gut microbiota has effects on the nervous system, and some nutrient-related factors can also affect neurogenesis via gut microbiota. Summary: Peripheral nerve injury is a condition in which the nerves in the peripheral nervous system become damaged. After the trauma, the peripheral nerve is hardly repaired due to the following reasons; the disability of the regeneration of motor neurons, the lack of a survival environment for Schwann cells, and the poor ability of the nerves to regenerate. Nutrition-related factors, the effects of which were described in recent years, should be more taken into account more.

Intermittent administration of a fasting-mimicking diet intervenes in diabetes progression, restores β cells and reconstructs gut microbiota in mice

Fasting and especially intermittent fasting have been shown to be an effective intervention in many diseases, such as obesity and diabetes. The fasting-mimicking diet (FMD) has recently been found to ameliorate metabolic disorders. To investigate the effect of a new type of low-protein low-carbohydrate FMD on diabetes, we tested an FMD in db/db mice, a genetic model of type 2 diabetes. The diet was administered every other week for a total of 8 weeks. The intermittent FMD normalized blood glucose levels in db/db mice, with significant improvements in insulin sensitivity and β cell function. The FMD also reduced hepatic steatosis in the mice. Deterioration of pancreatic islets and the loss of β cells in the diabetic mice were prevented by the FMD. The expression of β cell progenitor marker Ngn3 was increased by the FMD. In addition, the FMD led to the reconstruction of gut microbiota. Intermittent application of the FMD increased the genera of Parabacteroides and Blautia while reducing Prevotellaceae, Alistipes and Ruminococcaceae. The changes in these bacteria were also correlated with the fasting blood glucose levels of the mice. Furthermore, intermittent FMD was able to reduce fasting blood glucose level and increase β cells in STZ-induced type 1 diabetic mouse model. In conclusion, our study provides evidence that the intermittent application of an FMD is able to effectively intervene in the progression of diabetes in mice.

Fasting/Refeeding Cycles Prevent Myocardial Dysfunction and Morphology Damage in the Spontaneously Hypertensive Rats

Background

Caloric restriction is known to impair the cardiac function and morphology in hypertrophied hearts of spontaneously hypertensive rats (SHR); however, the influence of fasting/refeeding (RF) is unknown.

Objective

To investigate the fasting/refeeding approach on myocardial remodeling and function. In addition, the current study was designed to bring information regarding the mechanisms underlying the participation of Ca²⁺ handling and β-adrenergic system.

Methods

Sixty-day-old male SHR rats were submitted to food ad libitum (C), 50% food restriction (R₅₀) or RF cycles for 90 days. Cardiac remodeling was assessed by ultrastructure analysis and isolated papillary muscle function. The level of significance considered was 5% (α = 0.05).

Results

The RF rats presented lower cardiac atrophy than R₅₀ in relation to C rats. The C rats increased weight gain, R₅₀ maintained their initial body weight and RF rats increased and decreased weight during RF. The RF did not cause functional impairment because the isotonic and isometric parameters showed similar behavior to those of C. The isotonic and isometric cardiac parameters were significantly elevated in RF rats compared to R₅₀ rats. In addition, the R₅₀ rats had cardiac damage in relation to C for isotonic and isometric variables. While the R₅₀ rats showed focal changes in many muscle fibers, the RF rats displayed mild alterations, such as loss or disorganization of myofibrils.

Conclusion

Fasting/refeeding promotes cardiac beneficial effects and attenuates myocardial injury caused by caloric restriction in SHR rats, contributing to reduce the cardiovascular risk profile and morphological injuries. Furthermore, RF promotes mild improvement in Ca²⁺ handling and β-adrenergic system.

Implementation of environmental enrichment after middle age promotes healthy aging

With increases in life expectancy, it is vital to understand the dynamics of aging, their interaction with lifestyle factors, and the connections to age-related disease processes. Our work on environmental enrichment (EE), a housing environment boosting mental health, has revealed a novel anticancer and anti-obesity phenotype mediated by a brain-fat axis: the hypothalamic-sympathoneural-adipocyte (HSA) axis in young animals. Here we investigated EE effects on healthspan and lifespan when initiated after middle age. Short-term EE for six weeks activated the HSA axis in 10-month-old mice. Long-term EE for twelve months reduced adiposity, improved glucose tolerance, decreased leptin levels, enhanced motor abilities, and inhibited anxiety. In addition to adipose remodeling, EE decreased age-related liver steatosis, reduced hepatic glucose production, and increased glucose uptake by liver and adipose tissue contributing to the improved glycemic control. The EE-induced liver modulation was associated with a suppression of protein kinase Cε. Moreover, EE down-regulated the expression of inflammatory genes in the brain, adipose, and liver. EE initiated at 18-month of age significantly improved glycemic control and showed a trend of positive impact on mean lifespan. These data suggest that EE induces metabolic and behavioral adaptations that are shared by factors known to increase healthspan and lifespan.

Nutrients Other than Selenium Are Important for Promoting Children's Health in Kashin-Beck Disease Areas

Overall nutritional status has been proved associated with people's health. The overall nutritional status of children in Kashin-Beck disease (KBD) areas has been overlooked for decades. Therefore, it is worth investigating in the current generation to gather evidence and make suggestions for improvement. A cross-sectional study with three 24-h dietary recalls was conducted to collect raw data on the daily food intake of children. Recorded food was converted into daily nutrient intakes using CDGSS 3.0 software. WHO AnthroPlus software was used to analyse the BMI-for-age z-score (BAZ) for estimating the overall nutrition status of children. All the comparisons and regression analyses were conducted with SPSS 18.0 software. Multiple nutrient intakes among children from the Se-supplemented KBD-endemic were under the estimated average requirement. The protein-to-carbohydrate ratio (P/C ratio) was significantly higher in children from the non-Se-supplemented KBD-endemic area than the other areas (P < 0.001). The children's BAZ was negatively associated with age (B = -0.095, P < 0.001) and the number of KBD relatives (B = -0.277, P = 0.04), and it was positively associated with better housing conditions, receiving colostrum, and daily intakes of niacin and zinc by multivariate regression analysis (F = 10.337, R = 0.609, P < 0.001).Compared to non-Se-supplemented KBD-endemic area and non-endemic areas, children in Se-supplemented KBD-endemic areas have an insufficient intake of multiple nutrients. School breakfast and lunch programmes are recommended, and strict implementation is the key to ensuring a positive effect.

Limited daily feeding and intermittent feeding have different effects on regional brain energy homeostasis during aging

Albeit aging is an inevitable process, the rate of aging is susceptible to modifications. Dietary restriction (DR) is a vigorous nongenetic and nonpharmacological intervention that is known to delay aging and increase healthspan in diverse species. This study aimed to compare the impact of different restricting feeding regimes such as limited daily feeding (LDF, 60% AL) and intermittent feeding (IF) on brain energy homeostasis during aging. The analysis was focused on the key molecules in glucose and cholesterol metabolism in the cortex and hippocampus of middle-aged (12-month-old) and aged (24-month-old) male Wistar rats. We measured the impact of different DRs on the expression levels of AMPK, glucose transporters (GLUT1, GLUT3, GLUT4), and the rate-limiting enzyme in the cholesterol synthesis pathway (HMGCR). Additionally, we assessed the changes in the amounts of cholesterol, its metabolite, and precursors following LDF and IF. IF decreased the levels of AMPK and pAMPK in the cortex while the increased levels were detected in the hippocampus. Glucose metabolism was more affected in the cortex, while cholesterol metabolism was more influenced in the hippocampus. Overall, the hippocampus was more resilient to the DRs, with fewer changes compared to the cortex. We showed that LDF and IF differently affected the brain energy homeostasis during aging and that specific brain regions exhibited distinct vulnerabilities towards DRs. Consequently, special attention should be paid to the DR application among elderly as different phases of aging do not respond equally to altered nutritional regimes.

The sedentary (r)evolution: Have we lost our metabolic flexibility?

During the course of evolution, up until the agricultural revolution, environmental fluctuations forced the human species to develop a flexible metabolism in order to adapt its energy needs to various climate, seasonal and vegetation conditions. Metabolic flexibility safeguarded human survival independent of food availability. In modern times, humans switched their primal lifestyle towards a constant availability of energy-dense, yet often nutrient-deficient, foods, persistent psycho-emotional stressors and a lack of exercise. As a result, humans progressively gain metabolic disorders, such as the metabolic syndrome, type 2 diabetes, non-alcoholic fatty liver disease, certain types of cancer, cardiovascular disease and Alzheimer´s disease, wherever the sedentary lifestyle spreads in the world. For more than 2.5 million years, our capability to store fat for times of food shortage was an outstanding survival advantage. Nowadays, the same survival strategy in a completely altered surrounding is responsible for a constant accumulation of body fat. In this article, we argue that the metabolic disease epidemic is largely based on a deficit in metabolic flexibility. We hypothesize that the modern energetic inflexibility, typically displayed by symptoms of neuroglycopenia, can be reversed by re-cultivating suppressed metabolic programs, which became obsolete in an affluent environment, particularly the ability to easily switch to ketone body and fat oxidation. In a simplified model, the basic metabolic programs of humans' primal hunter-gatherer lifestyle are opposed to the current sedentary lifestyle. Those metabolic programs, which are chronically neglected in modern surroundings, are identified and conclusions for the prevention of chronic metabolic diseases are drawn.

The sedentary (r)evolution: Have we lost our metabolic flexibility?

During the course of evolution, up until the agricultural revolution, environmental fluctuations forced the human species to develop a flexible metabolism in order to adapt its energy needs to various climate, seasonal and vegetation conditions. Metabolic flexibility safeguarded human survival independent of food availability. In modern times, humans switched their primal lifestyle towards a constant availability of energy-dense, yet often nutrient-deficient, foods, persistent psycho-emotional stressors and a lack of exercise. As a result, humans progressively gain metabolic disorders, such as the metabolic syndrome, type 2 diabetes, non-alcoholic fatty liver disease, certain types of cancer, cardiovascular disease and Alzheimer´s disease, wherever the sedentary lifestyle spreads in the world. For more than 2.5 million years, our capability to store fat for times of food shortage was an outstanding survival advantage. Nowadays, the same survival strategy in a completely altered surrounding is responsible for a constant accumulation of body fat. In this article, we argue that the metabolic disease epidemic is largely based on a deficit in metabolic flexibility. We hypothesize that the modern energetic inflexibility, typically displayed by symptoms of neuroglycopenia, can be reversed by re-cultivating suppressed metabolic programs, which became obsolete in an affluent environment, particularly the ability to easily switch to ketone body and fat oxidation. In a simplified model, the basic metabolic programs of humans’ primal hunter-gatherer lifestyle are opposed to the current sedentary lifestyle. Those metabolic programs, which are chronically neglected in modern surroundings, are identified and conclusions for the prevention of chronic metabolic diseases are drawn.