-
1.
The effects of multi-nutrient formulas containing a combination of n-3 PUFA and B vitamins on cognition in the older adult: a systematic review and meta-analysis.
Fairbairn, P, Dyall, SC, Tsofliou, F
The British journal of nutrition. 2023;129(3):428-441
-
-
-
Free full text
-
Plain language summary
Due to the insidious onset, cognitive impairment often goes unnoticed for several years, with clinical diagnosis being made late into the disease progression. Cognition is critical for functional independence as people age, and intact cognition is vital for humans to communicate effectively. The aims of this study were to (i) investigate whether supplementation with a combination of omega-3 polyunsaturated fatty acids (n-3 PUFA) and B vitamins alone or as part of a multi-nutrient formula can prevent cognitive decline in older adults, and (ii) determine whether the effects of a single nutrient intervention with either n-3 PUFA or B vitamins could be modified by the status of the other nutrient. This study is a systematic review and meta-analysis of fourteen studies of which eleven were randomised controlled trials and the rest were post hoc analysis of randomised controlled trials. Results show a benefit of supplementing with nutrient formulas that contain both n-3 PUFA and B vitamins on global cognition and episodic memory with small to moderate effect sizes. In fact, they can help preserve cognition in the older adults. Authors conclude that more experimental work providing a combination of nutrients including both n-3 PUFA and B vitamins, in healthy older adults or those showing early signs of cognitive decline, is clearly warranted to better explore how nutrition can impact the trajectory of cognition in older adults.
Abstract
There is now evidence to suggest that there may be an interaction between B vitamins and n-3 PUFA, with suggestions that increasing intake of both nutrients simultaneously may benefit cognition in older adults. The aim of this systematic review was to investigate whether supplementation with a combination of n-3 PUFA and B vitamins can prevent cognitive decline in older adults. Randomised controlled trials conducted in older adults that measured cognitive function were retrieved. The included trials provided a combination of n-3 PUFA and B vitamins alone, or in combination with other nutrients. Trials that provided n-3 PUFA alone and also measured B vitamin status or provided B vitamin supplementation alone and measured n-3 PUFA status were also included. The databases searched were The Cochrane Library, EMBASE, CINAHL, Scopus and MEDLINE. A total of 14 papers were included in the analysis (n 4913; age: 60-70 years; follow-up 24 weeks to 4 years). The meta-analysis results found a significant benefit of nutrient formulas, which included both n-3 PUFA and B vitamins alongside other nutrients, v. placebo on global cognition assessed using composite scores from a neuropsychological test battery (G = 0·23, P = 0·002), global cognition using single measures of cognition (G = 0·28, P = 0·004) and episodic memory (G = 0·32, P = 0·001). The results indicate that providing a combination of n-3 PUFA and B vitamins as part of a multi-nutrient formula benefits cognition in older adults v. a placebo, and the potential for an interaction between these key nutrients should be considered in future experimental work.
-
2.
Can dementia risk be reduced by following the American Heart Association's Life's Simple 7? A systematic review and dose-response meta-analysis.
Wu, J, Xiong, Y, Xia, X, Orsini, N, Qiu, C, Kivipelto, M, Rizzuto, D, Wang, R
Ageing research reviews. 2023;83:101788
-
-
-
Free full text
Plain language summary
The American Heart Association (AHA) has defined ideal levels of seven modifiable cardiovascular health (CVH) factors, known as Life's Simple 7, that consist of smoking, physical activity, diet, body mass index, fasting blood glucose, total cholesterol, and blood pressure. Maintaining ideal levels of these factors has been recommended as a prevention strategy against not only cardiovascular diseases but also neurodegenerative disorders, e.g., cognitive decline and dementia. However, studies exploring the beneficial effects of the AHA’s CVH metrics on cognitive outcomes, especially among older populations, have been uncertain, and solid evidence is lacking in this field. This systematic review and meta-analysis aimed to quantify the relationship between the AHA’s CVH metrics and cognitive outcomes. 14 longitudinal studies were included in the meta-analysis. The results showed a considerable effect of a favourable total CVH score on reduced risk of incident dementia in adults aged 70 years or older. When looking at the individual factors, dementia risk can be reduced significantly if older adults achieved the recommended level of physical activity, blood glucose, or total cholesterol. The association with smoking appeared to be borderline, and there was no association between diet, body mass index hazard ratio or blood pressure and dementia risk. The authors concluded that their findings provide evidence that maintaining a favourable level of CVH score, either in mid- or late- life, would substantially reduce the risk of dementia among older adults. Preserving cardiovascular health by quitting smoking, engaging in physical exercise, controlling blood glucose and total cholesterol might be especially effective for forestalling cognitive decline and dementia.
Abstract
This study aimed to quantify the relationships between the American Heart Association (AHA) Cardiovascular Health (CVH) metrics, namely AHA Life's Simple 7, and cognitive outcomes. We searched PubMed and Embase (January 1, 2010-August 24, 2022) and finally included 14 longitudinal studies (311654 participants with 8006 incident dementia cases). Random-effects meta-analysis and one-stage linear mixed-effects models were performed. Increased CVH score seemed to associate with decreased risk of incident dementia in a linear manner, but this relationship varied by the measurement age of CVH metrics. That is, midlife CVH tended to have a linear association with late-life dementia risk, whereas a J-shaped association was observed between the late-life CVH score and dementia. In addition, late-life dementia risk was reduced significantly if individuals maintained an ideal level of AHA's CVH guidelines of physical activity, fasting plasma glucose, total cholesterol, and smoking. However, our meta-analysis did not show a significant association between CVH score and global cognitive decline rate. Following AHA's CVH guidelines and maintaining CVH at an optimal level would substantially reduce the late-life dementia risk. More research is required to explore the link between a favorable CVH score and cognitive trajectories among cognitively asymptomatic older populations.
-
3.
The Gut Microbiome in Early Life Stress: A Systematic Review.
Agusti, A, Lamers, F, Tamayo, M, Benito-Amat, C, Molina-Mendoza, GV, Penninx, BWJH, Sanz, Y
Nutrients. 2023;15(11)
-
-
-
-
Free full text
Plain language summary
Children exposed to early life stress (ELS) show alterations in brain development and are at increased risk of developing mental illness. This study aims to clarify whether ELS influences the gut microbiome and whether this can be a predictor for the development of mental disorders. 13 articles were included in this systemic review. 4 looked at pre-natal stress and 9 at post-natal stress. Prenatal stress (via maternal stress) may be associated with an increase in Proteobacteria phylum and with a lower abundance of Bifidobacterium and lactic acid bacteria. In the postnatal group, greater microbiome diversity was related to lower depression and anxiety. In boys scores for adaptive skills were higher in those with good levels of Bifidobacterium. A positive association was found between EA (early adversity) experiences and gastrointestinal symptoms and anxiety. This review demonstrates links between ELS and gut microbiome changes. Further research will be necessary to draw more robust conclusions.
Expert Review
Conflicts of interest:
None
Take Home Message:
- This systematic review consolidated and discussed existing evidence on the link between early life stress (ELS) and changes to the human microbiome
- Exposure to ELS, prenatal or postnatal during childhood and adolescence, may impact mental and physical health.
Evidence Category:
-
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
-
X
B: Systematic reviews including RCTs of limited number
-
C: Non-randomized trials, observational studies, narrative reviews
-
D: Case-reports, evidence-based clinical findings
-
E: Opinion piece, other
Summary Review:
Introduction
A systematic review was conducted to consolidate clinical evidence examining the impact of early life stress (ELS) on the human intestinal microbiome.
Method
Thirteen observational studies were included in the review, sourced from Pubmed, Scopus, Web of Science, and EMBASE. Methodological quality was assessed using the Newcastle-Ottawa Assessment Scale (NOS), with most studies scoring seven or eight out of nine stars.
Study designs varied, including prospective prenatal studies, postnatal longitudinal studies, case-control studies, and cross-sectional studies. Four prenatal studies were prospective in design. The other nine postnatal studies included one longitudinal study, five case-control studies, and three cross-sectional studies. All 13 studies were published between 2015 and 2022. Because study designs and outcome assessments varied, the results were presented in a narrative form. Data was extracted by 2 independent authors.
Results
The primary findings from the review were as follows:
- Four longitudinal stress studies indicated that pregnant mothers experiencing psychological stress, increased cortisol levels, HIV, and lack of social support exhibited a lower abundance of beneficial Bifidobacterium and an increased abundance of Enterobacter genus.
- One postnatal stress longitudinal study (n=260) demonstrated lower depression and anxiety and improved internalising behaviour in patients with high microbiome diversity.
- . One postnatal stress case-control study (n=344) showed changes in the microbiome and an abundance of several bacterial taxa in stressed groups, including genera Prevotella, Bacteroides (Bacteroidetes), Coprococcus, Streptococcus, and Escherichia.
- One cross-sectional study of 128 adults without psychiatric conditions revealed that higher stress correlated with increased levels of Bacteroides, Parabacteroides, Rhodococcus, Methanobrevibacter, and Roseburia at the genus level, as well as lower Phascolarcto bacterium and Firmicutes at the phylum level.
- One large prospective study (n=446) found infants exposed to higher cumulative stress exhibited an increased relative abundance of Proteobacteria groups and lower Bifidobacterium.
Conclusion:
Due to the inconsistency of study designs and their results this review failed to find consensus microbiome signatures associated with pre- or postnatal stress, or both.
Clinical practice applications:
- Early life stress, and alterations in the gut microbiome, have been linked to mental health conditions
- Maternal prenatal stress may be linked to emotional, behavioural, and cognitive outcomes in infants.
Considerations for future research:
- Future research should standardise questionnaires, to ensure consistency and comparability across studies
- Additionally, future studies should consider using standard procedures and specific species and strain resolution shotgun metagenomics sequencing
- Consideration should be given to the influence of environmental variables (diet, physical activity, etc.) and sex in gut microbiome analysis.
Abstract
Exposure to early life stress (ELS), prenatal or postnatal during childhood and adolescence, can significantly impact mental and physical health. The role of the intestinal microbiome in human health, and particularly mental health, is becoming increasingly evident. This systematic review aims to summarize the clinical data evaluating the effect of ELS on the human intestinal microbiome. The systematic review (CRD42022351092) was performed following PRISMA guidelines, with ELS considered as exposure to psychological stressors prenatally and during early life (childhood and adolescence). Thirteen articles met all inclusion criteria, and all studies reviewed found a link between ELS and the gut microbiome in both prenatal and postnatal periods. However, we failed to find consensus microbiome signatures associated with pre- or postnatal stress, or both. The inconsistency of results is likely attributed to various factors such as different experimental designs, ages examined, questionnaires, timing of sample collection and analysis methods, small population sizes, and the type of stressors. Additional studies using similar stressors and validated stress measures, as well as higher-resolution microbiome analytical approaches, are needed to draw definitive conclusions about the links between stress and the human gut microbiome.
-
4.
Time of the day of exercise impact on cardiovascular disease risk factors in adults: a systematic review and meta-analysis.
Sevilla-Lorente, R, Carneiro-Barrera, A, Molina-Garcia, P, Ruiz, JR, Amaro-Gahete, FJ
Journal of science and medicine in sport. 2023;26(3):169-179
-
-
-
Free full text
Plain language summary
In humans, shifted sleep patterns seem to interfere with several metabolic pathways. Shift work, short sleep duration, exposure to artificial light, inadequate eating time window, and lack of physical activity, are some characteristics of the modern lifestyle that contributes to the occurrence and worsening of cardiovascular disease (CVD). The aim of this study was to analyse the time of the day of exercise-induced effects on CVD risk factors in adults. This study was a systematic review and meta-analysis of twenty-two studies. Results showed that exercise produces an acute reduction of systolic blood pressure independently of the time of the day at which it is performed. Similarly, exercise produces an acute increase in blood glucose independently of the time of the day. Authors concluded that further research is needed to establish whether there is a diurnal variation of exercise on cardiovascular health and how it is related to health status, sex, or the type of exercise.
Abstract
OBJECTIVES To compare the effect of a single bout of morning vs. evening exercise on cardiovascular risk factors in adults. DESIGN Systematic review and meta-analysis. METHODS A systematic search of studies was conducted using PubMed and Web of Science from inception to June 2022. Selected studies accomplished the following criteria: crossover design, acute effect of exercise, blood pressure, blood glucose, and/or blood lipids as the study's endpoint, a washout period of at least 24 h, and adults. Meta-analysis was performed by analyzing: 1) separated effect of morning and evening exercise (pre vs. post); and 2) comparison between morning and evening exercise. RESULTS A total of 11 studies were included for systolic and diastolic blood pressure and 10 studies for blood glucose. Meta-analysis revealed no significant difference between morning vs. evening exercise for systolic blood pressure (g ∆ = 0.02), diastolic blood pressure (g ∆ = 0.01), or blood glucose (g ∆ = 0.15). Analysis of moderator variables (age, BMI, sex, health status, intensity and duration of exercise, and hour within the morning or evening) showed no significant morning vs. evening effect. CONCLUSIONS Overall, we found no influence of the time of the day on the acute effect of exercise on blood pressure neither on blood glucose.
-
5.
Effects of Probiotics on Autism Spectrum Disorder in Children: A Systematic Review and Meta-Analysis of Clinical Trials.
He, X, Liu, W, Tang, F, Chen, X, Song, G
Nutrients. 2023;15(6)
-
-
-
Free full text
Plain language summary
Autism spectrum disorder (ASD) is a developmental disability caused by differences in the brain and is characterized by a series of neurodevelopmental disorders, including language and social disorders, restricted interests, and repetitive stereotyped activities. The aim of this study was to explore whether probiotics could improve the overall severity of ASD symptoms in children. This study was a systematic review and meta-analysis of seven studies. Results showed that probiotic supplementation did not improve the associated behavioural symptoms in children with ASD. However, multiple-strain probiotic blend intervention exhibited a positive therapeutic effect on children with ASD and was more effective than single-strain probiotics in subgroup analyses. Authors concluded that to demonstrate the therapeutic effects of probiotics on children with ASD, randomised, double-blind, and placebo-controlled studies following strict trial guidelines are needed.
Abstract
Many studies have explored the efficacy of probiotics on autism spectrum disorder (ASD) in children, but there is no consensus on the curative effect. This systematic review and meta-analysis aimed to comprehensively investigate whether probiotics could improve behavioral symptoms in children with ASD. A systematic database search was conducted and a total of seven studies were included in the meta-analysis. We found a nonsignificant overall effect size of probiotics on behavioral symptoms in children with ASD (SMD = -0.24, 95% CI: -0.60 to 0.11, p = 0.18). However, a significant overall effect size was found in the subgroup of the probiotic blend (SMD = -0.42, 95% CI: -0.83 to -0.02, p = 0.04). Additionally, these studies provided limited evidence for the efficacy of probiotics due to their small sample sizes, a shorter intervention duration, different probiotics used, different scales used, and poor research quality. Thus, randomized, double-blind, and placebo-controlled studies following strict trial guidelines are needed to precisely demonstrate the therapeutic effects of probiotics on ASD in children.
-
6.
Mediterranean diet and structural neuroimaging biomarkers of Alzheimer's and cerebrovascular disease: A systematic review.
Gregory, S, Pullen, H, Ritchie, CW, Shannon, OM, Stevenson, EJ, Muniz-Terrera, G
Experimental gerontology. 2023;172:112065
-
-
-
-
Free full text
-
Plain language summary
Nearly a million people in the UK have Alzheimer's disease, the most common type of dementia. Mediterranean diet (MedDiet) adherence is associated with healthy brain ageing, a reduced stroke risk, and a lower incidence of dementia. Seven studies were included in this review to evaluate the effects of MedDiet on hippocampal volume and white matter hyperintensity volume, predictors of stroke and dementia. This systematic review did not reveal any associations between MedDiet adherence and hippocampal volume. However, there was a significant negative relationship between MedDiet adherence and white matter hyperintensity volume in two of the studies included. It is necessary to conduct more robust studies to investigate the associations between MedDiet adherence and structural brain imaging findings and understand the mechanisms behind dementia and other cerebrovascular diseases. This study could provide healthcare professionals with valuable information about the effects of increased MedDiet adherence on brain health, including its potential to delay neurodegenerative disease progression.
Expert Review
Conflicts of interest:
None
Take Home Message:
Due to inconclusive results on the associations between MedDiet adherence and AD and cerebrovascular related structural neuroimaging findings, specific recommendations for the MedDiet cannot be made on the basis of this study until further research has been completed.
Evidence Category:
-
X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
-
B: Systematic reviews including RCTs of limited number
-
C: Non-randomized trials, observational studies, narrative reviews
-
D: Case-reports, evidence-based clinical findings
-
E: Opinion piece, other
Summary Review:
Background:
Changes in hippocampal volume (HV) and white matter intensity volume (WMIV) have been identified as structural neuroimaging biomarkers of neurodegenerative disease such as Alzheimer’s Disease (AD) and Cerebrovascular disease (CVD) respectively. Evidence has shown adherence to the Mediterranean Diet (MedDiet) has been associated with reduced risk for strokes. This review evaluated the MedDiet in relation to HV and WMIV.
Methods:
The review followed PRISMA guidelines and was registered on PROSPERO. Literature searching resulted in seven studies published between 2012 and 2022, which met the inclusion criteria. Six studies analysed cross-sectional data and one analysed longitudinal data. The NIH Quality Assessment Tool for Observational and Cross-Sectional Studies was used to assess risk of bias.
Overall, the studies were rated as low-risk of bias with details of the research question, participant group exposure and outcome variables included. Due to moderate to high heterogeneity in some studies, a meta-analysis was deemed unsuitable and narrative synthesis was conducted to present the results.
Results:
Mean participant age ranged from 53.19 to 80.3 years and volunteers were healthy or had subjective cognitive decline and a few participants had dementia (n=46).
Hippocampal Volume:
Four studies included 20,077 participants and found no significant associations between MedDiet adherence and hippocampal volume. All four studies were cross-sectional from larger cohort studies. To establish causative relationships longitudinal and RCT trials are required.
White Matter Hyperintensity Volumes:
Four studies included 1938 participants. Two studies found a significant negative association between MedDiet and WMHV, demonstrating higher Mediterranean Scores were associated with lower level of WHMV. The other two studies found no significant associations.
Although the review methodology with a piloted search strategy was considered a key strength, the lack of meta-analysis as planned in the a priori protocol, due to minimal eligible studies and high heterogeneity was a limitation as well as the restriction of brain imaging outcomes.
Conclusion:
Overall, these results are inconclusive on the associations between the MedDiet and HV and WMHV, and identify a gap in the knowledge, therefore further research such as RCT’s remains a priority to further understand the impact diet may have on neuroimaging markers of AD and CVD.
Clinical practice applications:
There were no significant associations between MedDiet adherence and HV, which was surprising given the evidence stating adherence to the MedDiet is associated with a lower incidence of dementia and stroke. However all four studies were cross-sectional studies and in order to detect causal associations, longitudinal and RCT’s are needed. Two studies did show a significant association between higher MedDiet adherence and lower WMHV, whereas two studies reported no significant associations.
Caution needs to be taken when recommending the MedDiet specifically for a reduction in HV and WMHV until further research has been undertaken.
Considerations for future research:
Future research should consider:
- larger cohorts and participants from the Mediterranean region where lifelong adherence to the MedDiet is more likely.
- looking at other risk factors to include obesity, lack of activity, poor sleep quality and stress.
- evaluating different socio-economic status, which has been shown to impact dietary behaviour.
- alternative imaging outcomes such as cortical thinning, PET amyloid and tau.
- . gold standard for methodology in particular dietary analysis and scanning and outcome derivation.
Abstract
Previous studies have demonstrated an association between adherence to the Mediterranean diet (MedDiet) and better cognitive performance, lower incidence of dementia and lower Alzheimer's disease biomarker burden. The aim of this systematic review was to evaluate the evidence base for MedDiet associations with hippocampal volume and white matter hyperintensity volume (WMHV). We searched systematically for studies reporting on MedDiet and hippocampal volume or WMHV in MedLine, EMBASE, CINAHL and PsycInfo. Searches were initially carried out on 21st July 2021 with final searches run on 23rd November 2022. Risk of bias was assessed using the NIH Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Of an initial 112 papers identified, seven papers were eligible for inclusion in the review reporting on 21,933 participants. Four studies reported on hippocampal volume, with inconclusive or no associations seen with MedDiet adherence. Two studies found a significant association between higher MedDiet adherence and lower WMHV, while two other studies found no significant associations. Overall these results highlight a gap in our knowledge about the associations between the MedDiet and AD and cerebrovascular related structural neuroimaging findings.
-
7.
The effects of time-restricted eating on sleep, cognitive decline, and Alzheimer's disease.
Ezzati, A, Pak, VM
Experimental gerontology. 2023;171:112033
-
-
-
-
Free full text
-
Plain language summary
The ageing population is expected to double, with one in four people being over 65 years in Western countries by 2050. As a consequence, the presentation of age-related disorders like Alzheimer's disease (AD) and mild cognitive impairment (MCI) is likely to increase. MCI, a pre-stage of dementia, is considered reversible. However, there are no known cures for AD so far. Hence interventions such as lifestyle modifications that can delay the onset and progression of the disease are of great interest. Previous research demonstrated that calorie restriction (CR) and time-restricted eating (TRE) have beneficial effects on brain function. The authors of this article sought to summarize the current evidence of such eating patterns, as well as their underlying mechanisms and potential benefits concerning MCI and AD. The review also looked at sleep - as sleep disturbances are a risk factor and are associated with both conditions - and the effects of sleep on cognitive decline and neuroinflammatory markers. TRE presents itself as a promising intervention as it can restore the integrity of the blood-brain barrier and support healthy brain function whilst reducing oxidative stress and inflammation. Furthermore, it can be leveraged for weight and glucose management. Preliminary results also indicate a positive impact on sleep, with adequate sleep benefiting cognitive health. As this is a relatively new field, there is still much more to be understood about the underlying mechanisms, with the optimal time window for fasting needing to be determined. The authors advocate for more research on how TRE and sleep relates to neurodegenerative disease.
Expert Review
Conflicts of interest:
None
Take Home Message:
- To highlight the potential benefits of time-restricted eating (TRE) as a potential preventative approach to delay the onset and progression of neurodegenerative disease such as AD
Evidence Category:
-
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
-
B: Systematic reviews including RCTs of limited number
-
X
C: Non-randomized trials, observational studies, narrative reviews
-
D: Case-reports, evidence-based clinical findings
-
E: Opinion piece, other
Summary Review:
- The authors highlight Alzheimer's disease (AD) is the most prevalent neurodegenerative disease affecting over 50 million aging people worldwide. While no cure is known for AD, this review proposes lifestyle interventions such as time-restricted eating (TRE) as a potential approach to delay the onset and progression of a neurodegenerative disease and could hint at autophagic mechanisms
- TRE involves strategically limiting the eating window to 8- to 12-h with fasting—drinking only water and calorie-free coffee/tea—for 12 to 16 h within a 24-h cycle.
Objectives
- To investigate the effects of TRE on sleep and cognitive decline in healthy individuals
Results
- Nine RCTs with varied length between one and sixteen weeks were examined
- A 5-week randomised controlled trial (RCT) showed no significant change in sleep quality between early TRE (fasting between 6 a.m.–3 p.m.), mid-day TRE (11 a.m.–8 p. m.) and control (ad lib intake) in 82 healthy subjects without obesity but the sleep quality improvement was greater in early TRE group (PSQI:Δ=−1.08±1.78vs.Δ=−0.22±2.19andΔ=−0.36±1.73, respectively).
- Sleep quality using the myCircadianClock app reported significant improvement in sleep quality (23 %) following a 12-week single arm intervention of 10-h TRE.
- Following a 16-week TRE intervention sleep duration was reported to be improved from a subjective score of 6 at base line to 8 after 36 weeks in eight overweight and obese subjects; however, the study used a subjective self-assessment survey for measuring sleep duration.
- The Pittsburgh Sleep Quality Index (PSQI) was carried out to assess sleep quality and disturbances in six trials but no trial reported significant improvement in sleep quality using the PSQI survey with TRE
Conclusion
- Authors highlight TRE as promising for its potential to reduce the markers of aging and neurodegenerative disease.
Clinical practice applications:
- To inform practitioners of the potential benefits of TRE that involves limiting the eating window to 8- to 12-h with fasting—drinking only water and calorie-free coffee/tea—for 12 to 16 h within a 24-h cycle.
- TRE may improve regulation of circadian rhythm and autophagy through aligning food intake with circadian rhythm, which coordinates metabolism and physiological functions including glucose, insulin sensitivity, lipid levels, energy expenditure, inflammation, sleep and cognitive function.
- TRE activates a metabolic switch which occurs 12–36 h after fasting is initiated and free fatty acids are released into the blood.
- TRE improved sleep quality and sleep duration, where a longer fasting period in TRE approach (≥12 h fasting) was associated with significantly higher sleep duration.
Considerations for future research:
- The potential benefits of TRE in neurodegenerative diseases such as AD should be further investigated clinically.
- The optimal time to initiate fasting needs to be identified in future trials.
- The potential benefits of TRE in neurodegenerative diseases such as AD in the context of sleep should be further investigated.
Abstract
According to the United Nations, by 2050, one in six individuals will be over age 65 globally, and one in four people would be aged 65 and older in western countries. The unprecedented growth of the aging population is associated with increased age-related disorders like Alzheimer's disease (AD) and Mild cognitive impairment (MCI). To date, no cure is known for AD, thus lifestyle interventions including calorie restriction (CR) and time-restricted eating (TRE) are proposed as potential approach to delay the onset and progression of the disease. Sleep disturbances are common in people with MCI and AD. Moreover, accumulating data indicates that pro-inflammatory cytokines including tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), IL-6, IL-8 and IL-10 increase in individuals with AD and MCI versus healthy subjects. Thus, the purpose of the present review is to describe the potential effects of TRE on sleep, cognition decline, and neuroinflammatory markers in humans. Preliminary evidence suggests that TRE may produce neuroprotective effects on cognition and reduce neuroinflammatory markers related to AD in humans. To date, no studies investigated the effects of TRE on sleep disturbances and patients with AD. Thereby, the impact of TRE on cognition in individuals with cognitive decline and AD needs to be investigated further in randomized controlled trials (RCTs).
-
8.
Effectiveness of wearable activity trackers to increase physical activity and improve health: a systematic review of systematic reviews and meta-analyses.
Ferguson, T, Olds, T, Curtis, R, Blake, H, Crozier, AJ, Dankiw, K, Dumuid, D, Kasai, D, O'Connor, E, Virgara, R, et al
The Lancet. Digital health. 2022;4(8):e615-e626
-
-
-
Free full text
Plain language summary
A sedentary or physically inactive lifestyle significantly contributes to non-communicable diseases such as coronary heart disease, type 2 diabetes and stroke. Wearable activity trackers are low-cost solutions that encourage users to engage in physical activity. This umbrella review of systematic reviews and meta-analyses investigated the benefits of wearable activity trackers in improving physical activity levels and their beneficial effects on physiological and psychosocial outcomes. This umbrella review included thirty-nine systematic reviews, of which twenty-five systematic reviews included meta-analyses of the benefits of wearable trackers on physical activity levels. Results of this umbrella review suggest that wearable trackers increased physical activity levels, especially daily steps count and energy expenditure. The physiological outcomes included improvements in BMI, blood pressure, cholesterol, glycosylated haemoglobin, waist circumference, and body weight. There was also a slight improvement in the quality of life of the participants who used wearable activity trackers. Further robust studies are required to evaluate the effects of wearable trackers on the psychosocial outcomes in people with mental illness. However, healthcare professionals can use the results of this study to understand the impact of wearable trackers on physiological and psychosocial effects in a non-clinical population.
Abstract
Wearable activity trackers offer an appealing, low-cost tool to address physical inactivity. This systematic review of systematic reviews and meta-analyses (umbrella review) aimed to examine the effectiveness of activity trackers for improving physical activity and related physiological and psychosocial outcomes in clinical and non-clinical populations. Seven databases (Embase, MEDLINE, Ovid Emcare, Scopus, SPORTDiscus, the Cochrane Library, and Web of Science) were searched from database inception to April 8, 2021. Systematic reviews of primary studies using activity trackers as interventions and reporting physical activity, physiological, or psychosocial outcomes were eligible for inclusion. In total, 39 systematic reviews and meta-analyses were identified, reporting results from 163 992 participants spanning all age groups, from both healthy and clinical populations. Taken together, the meta-analyses suggested activity trackers improved physical activity (standardised mean difference [SMD] 0·3-0·6), body composition (SMD 0·7-2·0), and fitness (SMD 0·3), equating to approximately 1800 extra steps per day, 40 min per day more walking, and reductions of approximately 1 kg in bodyweight. Effects for other physiological (blood pressure, cholesterol, and glycosylated haemoglobin) and psychosocial (quality of life and pain) outcomes were typically small and often non-significant. Activity trackers appear to be effective at increasing physical activity in a variety of age groups and clinical and non-clinical populations. The benefit is clinically important and is sustained over time. Based on the studies evaluated, there is sufficient evidence to recommend the use of activity trackers.
-
9.
A Systematic Review of the Impact of the First Year of COVID-19 on Obesity Risk Factors: A Pandemic Fueling a Pandemic?
Daniels, NF, Burrin, C, Chan, T, Fusco, F
Current developments in nutrition. 2022;6(4):nzac011
-
-
-
Free full text
Plain language summary
Coronavirus disease 2019 (COVID-19) is one of the most serious infectious disease outbreaks in recent history. Among the factors that can increase the risk of obesity, some seem to play a more prominent role than others such as depression, emotional eating, sedentary lifestyle and the socioeconomic status. The aim of this study was to explore the indirect effects of the first year of COVID-19 on obesity and its risk factors. This study is a systematic review of 87 studies with over 350,000 participants. Results show that: - overall, there was a general trend of weight gain during the pandemic. - there were differences in dietary changes, with some studies showing an improvement in diet. - some beneficial effects were observed in the dieting domain, such as higher consumption of home-cooked meals and healthy food (e.g., vegetables). However, there was an increasing trend in the overall food and alcohol consumption. - financial hardship and job loss were unavoidable consequences of the pandemic lockdown. However, although the impact of the countermeasures used to curb the COVID-19 pandemic was evident on obesity risk factors, none of the studies included in the research explored the direct impact of the risk factors on obesity itself. Authors conclude by pointing out the need for future research that aims at strengthening the link between stressful circumstances and a rise in risk factors for obesity and weight gain.
Abstract
Obesity is increasingly prevalent worldwide. Associated risk factors, including depression, socioeconomic stress, poor diet, and lack of physical activity, have all been impacted by the coronavirus disease 2019 (COVID-19) pandemic. This systematic review aims to explore the indirect effects of the first year of COVID-19 on obesity and its risk factors. A literature search of PubMed and EMBASE was performed from 1 January 2020 to 31 December 2020 to identify relevant studies pertaining to the first year of the COVID-19 pandemic (PROSPERO; CRD42020219433). All English-language studies on weight change and key obesity risk factors (psychosocial and socioeconomic health) during the COVID-19 pandemic were considered for inclusion. Of 805 full-text articles that were reviewed, 87 were included for analysis. The included studies observed increased food and alcohol consumption, increased sedentary time, worsening depressive symptoms, and increased financial stress. Overall, these results suggest that COVID-19 has exacerbated the current risk factors for obesity and is likely to worsen obesity rates in the near future. Future studies, and policy makers, will need to carefully consider their interdependency to develop effective interventions able to mitigate the obesity pandemic.
-
10.
Amino Acids, B Vitamins, and Choline May Independently and Collaboratively Influence the Incidence and Core Symptoms of Autism Spectrum Disorder.
Jennings, L, Basiri, R
Nutrients. 2022;14(14)
-
-
-
Free full text
Plain language summary
Autistic disorder, Asperger syndrome, and pervasive developmental disorder can be categorized under autism spectrum disorder (ASD). ASD can result in restrictive, repetitive, and stereotypical behaviour patterns and cause impairments in social interaction and verbal and nonverbal communication. The aim of this study was to examine the effects of nutritional status and supplementation on the incidence and or severity of ASD symptoms using currently available resources. This study is a literature review of fifteen studies. Results show that children with ASD have higher rates of abnormal amino acids and lower blood levels of choline, vitamin B6, vitamin B12, and folate when compared to those without ASD. Furthermore, increasing dietary intake of choline could improve anxious behaviours, receptive language skills, social behaviour, sensory processing, and other symptoms which rely on ion transport in individuals with ASD. Authors conclude that altering nutritional status can be an affordable and effective way to prevent ASD and improve the quality of life for families and individuals impacted by ASD.
Abstract
Autism spectrum disorder (ASD) is a developmental disorder of variable severity, characterized by difficulties in social interaction, communication, and restricted or repetitive patterns of thought and behavior. In 2018, the incidence of ASD was 2.4 times higher than estimated in 2000. Behavior and brain development abnormalities are present in the complex disorder of ASD. Nutritional status plays a key role in the incidence and severity of the core symptoms of ASD. The aim of this study was to review the available peer-reviewed studies that evaluated the relationship between amino acids, choline, B vitamins, and ASD incidence and/or severity of symptoms. Through examining plasma profiles, urine samples, and dietary intake, researchers found that low choline, abnormal amino acid, and low B vitamin levels were present in children with ASD compared to those without ASD. The evidence supports the need for future research that implements simultaneous supplementation of all essential nutrients in individuals with ASD and among prenatal mothers. Future evidence could lead to scientific breakthroughs, ultimately reducing the rates of ASD incidence and severity of symptoms by applying nutritional interventions in at-risk populations.