The feasibility and acceptability of a rewards system based on food purchasing behaviour in secondary school cashless canteens: the Eat4Treats (E4T) cluster feasibility, non-randomised, controlled intervention study.

BACKGROUND: Using rewards may be an effective method to positively influence children's eating behaviour but evidence to date is limited, particularly in older children. The cashless canteen systems in schools provides a unique opportunity to implement a food-based reward scheme but intervention development work and feasibility testing is needed. The overall aim of the E4T feasibility study was to examine the feasibility and acceptability of implementing a rewards scheme based on the food purchasing behaviour of pupils in cashless canteens in secondary schools. METHODS: A non-randomised, controlled, parallel-group cluster feasibility study conducted in four secondary schools (two intervention and two control) serving areas of the highest social deprivation in Northern Ireland. During the 4-month trial, pupils earned points for foods purchased at the school canteen, with better nutritional choices having a higher value. Pupils could exchange the points they earned for rewards (e.g. stationery, vouchers, sports equipment) via the E4T website. Qualitative and quantitative data was collected from year 9 and 10 pupils (boys and girls aged 12-14 years), teachers and canteen staff to address the feasibility questions. RESULTS: Two intervention (one urban, one rural) and one control (urban) school completed the study. Seventy-one percent of 12-14-year-old pupils consented to take part; 1% of parents opted their child out of the study. Questionnaire completion rates were high (6 and 11% of questionnaires were partially completed at baseline and follow-up respectively). Collecting data on food consumed in the canteen was challenging logistically. Focus groups with pupils indicated that the overall concept of E4T was well received and there was a high degree of satisfaction with the rewards available. Pupils and teachers made several suggestions for improvements. CONCLUSIONS: E4T was successfully implemented as a result of collaboration between schools, school canteens and cashless canteen providers working with a multidisciplinary research team. It was acceptable to pupils, teachers and canteen staff. The findings suggest a few areas for refining implementation and evaluation processes that would need to be considered in the design of a larger trial, particularly resources required to streamline implementation and ways to optimise pupil engagement. TRIAL REGISTRATION: Under review with https://www. CLINICALTRIALS: gov (retrospective registration-reg number and weblink to be added).

Adherence to the Eatwell Guide and population and planetary health: A Rank Prize Forum report.

This report summarises a Forum conducted in June 2023 to explore the current state of the knowledge around the Eatwell Guide, which is the UK government's healthy eating tool, in relation to population and planetary health. The 1.5-day Forum highlighted the limited, albeit promising evidence linking higher adherence to the Eatwell Guide with favourable health outcomes, including reduced overall mortality risk, lower abdominal obesity in post-menopausal women and improved cardiometabolic health markers. Similarly, evidence was presented to suggest that higher adherence to the Eatwell Guide is associated with reduced greenhouse gas emissions. Presentations were given around cultural adaptations of the Eatwell Guide, including African Heritage and South Asian versions, which are designed to increase the acceptability and uptake of the Eatwell Guide in these communities in the United Kingdom. Presentations highlighted ongoing work relevant to the applications of the Eatwell Guide in randomised controlled trials and public health settings, including the development of a screening tool to quantify Eatwell Guide adherence. The Forum ended with a World Café-style event, in which the strengths and limitations of the Eatwell Guide were discussed, and directions for future research were identified. This Forum report serves as a primer on the current state of the knowledge on the Eatwell Guide and population and planetary health and will be of interest to researchers, healthcare professionals and public health officials.

Diet patterns and cognitive performance in a UK Female Twin Registry (TwinsUK).

BACKGROUND: Plant-based diets may provide protection against cognitive decline and Alzheimer's disease, but observational data have not been consistent. Previous studies include early life confounding from socioeconomic conditions and genetics that are known to influence both cognitive performance and diet behaviour. This study investigated associations between Mediterranean (MED) diet and MIND diets and cognitive performance accounting for shared genotype and early-life environmental exposures in female twins. METHODS: Diet scores were examined in 509 female twins enrolled in TwinsUK study. The Cambridge Neuropsychological Test Automated Battery was used to assess cognition at baseline and 10 years later (in n = 275). A co-twin case-control study for discordant monozygotic (MZ) twins examined effects of diet on cognitive performance independent of genetic factors. Differences in relative abundance of taxa at 10-year follow-up were explored in subsamples. RESULTS: Each 1-point increase in MIND or MED diet score was associated with 1.75 (95% CI: - 2.96, - 0.54, p = 0.005 and q = 0.11) and 1.67 (95% CI: - 2.71, - 0.65, p = 0.002 and q = 0.02) fewer respective errors in paired-associates learning. Within each MZ pair, the twin with the high diet score had better preservation in spatial span especially for MED diet (p = 0.02). There were no differences between diet scores and 10-year change in the other cognitive tests. MIND diet adherence was associated with higher relative abundance of Ruminococcaceae UCG-010 (0.30% (95% CI 0.17, 0.62), q = 0.05) which was also associated with less decline in global cognition over 10 years (0.22 (95% CI 0.06, 0.39), p = 0.01). CONCLUSIONS: MIND or MED diets could help to preserve some cognitive abilities in midlife, particularly episodic and visuospatial working memory. Effects may be mediated by high dietary fibre content and increased abundance of short-chain fatty acid producing gut bacteria. Longer follow-up with repeated measures of cognition will determine whether diet can influence changes in cognition occurring in older age.

Effects of PROtein enriched MEDiterranean Diet and EXercise on nutritional status and cognition in adults at risk of undernutrition and cognitive decline: the PROMED-EX Randomised Controlled Trial.

INTRODUCTION: Undernutrition leading to unplanned weight loss is common in older age and has been linked to increased dementia risk in later life. Weight loss can precede dementia by a decade or more, providing a unique opportunity for early intervention to correct undernutrition and potentially prevent or delay cognitive impairment. The combined effects of diet and exercise on undernutrition have not yet been evaluated. The objective of this trial is to determine the effect of a protein-enriched Mediterranean diet, with and without exercise, on nutritional status and cognitive performance in older adults at risk of undernutrition and cognitive decline. METHODS: One hundred and five participants aged 60 years and over at risk of undernutrition and with subjective cognitive decline will be recruited to participate in a 6-month, single-blind, parallel-group randomised controlled trial. Participants will be block randomised into one of three groups: group 1-PROMED-EX (diet+exercise), group 2-PROMED (diet only) and group 3-standard care (control). The primary outcome is nutritional status measured using the Mini Nutritional Assessment. Secondary outcomes include cognitive function, nutritional intake, body composition, physical function and quality of life. Mechanistic pathways for potential diet and exercise-induced change in nutritional status and cognition will be explored by measuring inflammatory, metabolic, nutritional and metabolomic biomarkers. ETHICS AND DISSEMINATION: The study is approved by the UK Office for Research Ethics Committee (ref: 21/NW/0215). Written informed consent will be obtained from participants prior to recruitment. Research results will be disseminated to the public via meetings and media and the scientific community through conference presentations and publication in academic journals. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT05166564).

A peer support dietary change intervention for encouraging adoption and maintenance of the Mediterranean diet in a non-Mediterranean population (TEAM-MED): lessons learned and suggested improvements.

Peer support interventions for dietary change may offer cost-effective alternatives to interventions led by health professionals. This process evaluation of a trial to encourage the adoption and maintenance of a Mediterranean diet in a Northern European population at high CVD risk (TEAM-MED) aimed to investigate the feasibility of implementing a group-based peer support intervention for dietary change, positive elements of the intervention and aspects that could be improved. Data on training and support for the peer supporters; intervention fidelity and acceptability; acceptability of data collection processes for the trial and reasons for withdrawal from the trial were considered. Data were collected from observations, questionnaires and interviews, with both peer supporters and trial participants. Peer supporters were recruited and trained to result in successful implementation of the intervention; all intended sessions were run, with the majority of elements included. Peer supporters were complimentary of the training, and positive comments from participants centred around the peer supporters, the intervention materials and the supportive nature of the group sessions. Attendance at the group sessions, however, waned over the intervention, with suggested effects on intervention engagement, enthusiasm and group cohesion. Reduced attendance was reportedly a result of meeting (in)frequency and organisational concerns, but increased social activities and group-based activities may also increase engagement, group cohesion and attendance. The peer support intervention was successfully implemented and tested, but improvements can be suggested and may enhance the successful nature of these types of interventions. Some consideration of personal preferences may also improve outcomes.

Whole Dietary Patterns, Cognitive Decline and Cognitive Disorders: A Systematic Review of Prospective and Intervention Studies.

Dementia prevalence is a global public health concern. Adherence towards a healthy dietary pattern (DP) may reduce the risk of cognitive decline and dementia. This narrative systematic review aimed to synthesise prospective and intervention study data to evaluate the impact of a-posteriori and a-priori derived DPs on cognitive ageing, from cognitive decline to incident dementia. Ninety-three studies were included: 83 prospective studies and 10 randomised controlled trials (RCT). Most prospective studies (77%) examined a-priori DPs, with the Mediterranean diet examined most frequently. A total of 52% of prospective and 50% of RCTs reported a protective relationship between 'healthy' DPs and global cognitive decline. Overall, 59% of prospective studies reported positive associations between healthy DPs and risk of cognitive disorder. Incident cognitive disorder was examined by only one intervention study (subgroup analysis) which reported a beneficial effect of a low-fat diet on risk of probable dementia in women. Unhealthy DPs were examined less frequently (n = 17; 21%), with 41% of these studies reporting associations between adherence and poorer cognitive outcomes. Overall, there were mixed results for healthy and unhealthy DPs on cognition, likely due to between-study heterogeneity. Standardisation of diet exposure and cognitive outcome measurement would help to reduce this. Future research would benefit from investigating effects of culturally appropriate DPs on individual cognitive domains and incident cognitive disorders in diverse and high-risk populations.

A qualitative study to inform adaptations to a brain health intervention for older adults with type 2 diabetes living in rural regions of Ireland.

AIMS: Type 2 diabetes is a risk factor for late-life dementia, but dementia prevention strategies have yet to be comprehensively evaluated in people with diabetes. The Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) demonstrated cognitive benefits of a 2-year multidomain lifestyle intervention. However, given the intensive nature of FINGER, there is uncertainty about whether it can be implemented in other high-risk populations. Our aim was to explore attitudes towards dementia risk, and barriers to an intervention based on the FINGER model in older adults with type 2 diabetes living in rural areas of Ireland. METHODS: Focus groups were conducted with 21 adults (11 men and 10 women) aged 60+ years with type 2 diabetes living in border regions of north and south Ireland. Data were analysed using thematic analysis. RESULTS: There was limited understanding of diabetes as a risk factor for late-life dementia. The main barriers to engagement with the multidomain intervention were eating foods that were not compatible with cultural norms, time and travel constraints, and perceived lack of self-efficacy and self-motivation for adopting the desired diet, exercise and computerised cognitive training (CCT) behaviours. Facilitators for intervention acceptability included the provision of culturally tailored and personalised education, support from a trusted source, and inclusion of goal setting and self-monitoring behavioural strategies. CONCLUSIONS: While there was high acceptability for a brain health intervention, several barriers including cultural food norms and low self-efficacy for adopting the diet, exercise and CCT components would need to be considered in the intervention design. Findings from this study will be used to inform local decisions regarding the adaptation of FINGER for people with type 2 diabetes. The feasibility of the adapted multidomain intervention will then be evaluated in a future pilot trial.

Behaviour Change Techniques in Computerized Cognitive Training for Cognitively Healthy Older Adults: A Systematic Review.

We aimed to describe behaviour change techniques (BCT) used in trials evaluating computerised cognitive training (CCT) in cognitively healthy older adults, and explore whether BCTs are associated with improved adherence and efficacy. The 90 papers included in a recent meta-analysis were reviewed for information about adherence and use of BCTs in accordance with the Behaviour Change Taxonomy. Studies using a specific BCT were compared with studies not using that BCT on efficacy (difference in Hedges' g [Δg]) using three level meta-regression models and on median adherence using the Wilcoxon test. The median number of BCTs per study was 3 (interquartile range [IQR] = 2-5). 'Feedback on behaviour' (if provided by a person; Δg = -0.19, 95% confidence interval [CI] = -0.31;-0.07) and 'non-specific reward' (Δg = -0.19, CI = -0.34;-0.05) were associated with lower efficacy. Certain BCTs that involve personal contact may be beneficial, although none were statistically significantly associated with greater efficacy. The median percentage of adherence was 90% (IQR = 81-95). Adherence was higher in studies using the BCT 'self-monitoring of behaviour' and lower in studies using the BCT 'graded tasks' than studies not using these BCTs (p < 0.001). These findings provide first evidence that BCTs can influence both adherence to and efficacy of CCT programs in cognitively healthy older adults.

Oral nutritional interventions in frail older people who are malnourished or at risk of malnutrition: a systematic review.

BACKGROUND: Malnutrition worsens the health of frail older adults. Current treatments for malnutrition may include prescribed oral nutritional supplements, which are multinutrient products containing macronutrients and micronutrients. OBJECTIVE: To assess the effectiveness and cost-effectiveness of oral nutritional supplements (with or without other dietary interventions) in frail older people who are malnourished or at risk of malnutrition. DATA SOURCES: MEDLINE, EMBASE, Cochrane Library, Scopus, CINAHL (Cumulative Index to Nursing and Allied Health Literature) and grey literature were searched from inception to 13 September 2021. REVIEW METHODS: A systematic review and meta-analysis was conducted to evaluate the effectiveness and cost-effectiveness of oral nutritional supplements in frail older people (aged ≥ 65 years) who are malnourished or at risk of malnutrition (defined as undernutrition as per National Institute for Health and Care Excellence guidelines). Meta-analysis and network meta-analysis were undertaken, where feasible, along with a narrative synthesis. A cost-effectiveness review was reported narratively. A de novo model was developed using effectiveness evidence identified in the systematic review to estimate the cost-effectiveness of oral nutritional supplements. RESULTS: Eleven studies (n = 822 participants) were included in the effectiveness review, six of which were fully or partly funded by industry. Meta-analyses suggested positive effects of oral nutritional supplements compared with standard care for energy intake (kcal) (standardised mean difference 1.02, 95% confidence interval 0.15 to 1.88; very low quality evidence) and poor mobility (mean difference 0.03, p < 0.00001, 95% confidence interval 0.02 to 0.04; very low quality evidence) but no evidence of an effect for body weight (mean difference 1.31, 95% confidence interval -0.05 to 2.66; very low quality evidence) and body mass index (mean difference 0.54, 95% confidence interval -0.03 to 1.11; very low quality evidence). Pooled results for other outcomes were statistically non-significant. There was mixed narrative evidence regarding the effect of oral nutritional supplements on quality of life. Network meta-analysis could be conducted only for body weight and grip strength; there was evidence of an effect for oral nutritional supplements compared with standard care for body weight only. Study quality was mixed; the randomisation method was typically poorly reported. One economic evaluation, in a care home setting, was included. This was a well-conducted study showing that oral nutritional supplements could be cost-effective. Cost-effectiveness analysis suggested that oral nutritional supplements may only be cost-effective for people with lower body mass index (< 21 kg/m2) using cheaper oral nutritional supplements products that require minimal staff time to administer. LIMITATIONS: The review scope was narrow in focus as few primary studies used frailty measures (or our proxy criteria). This resulted in only 11 included studies. The small evidence base and varied quality of evidence meant that it was not possible to determine accurate estimates of the effectiveness or cost-effectiveness of oral nutritional supplements. Furthermore, only English-language publications were considered. CONCLUSIONS: Overall, the review found little evidence of oral nutritional supplements having significant effects on reducing malnutrition or its adverse outcomes in frail older adults. FUTURE WORK: Future research should focus on independent, high-quality, adequately powered studies to investigate oral nutritional supplements alongside other nutritional interventions, with longer-term follow-up and detailed analysis of determinants, intervention components and cost-effectiveness. STUDY REGISTRATION: This study is registered as PROSPERO CRD42020170906. FUNDING: This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 51. See the NIHR Journals Library website for further project information.

WHAT WAS THE QUESTION?: Malnutrition, in the form of undernutrition, is very common in frail older people. Dietary advice is recommended (e.g. adding nutrients to meals) for older adults who are malnourished, while powdered or liquid supplements (oral nutritional supplements) can be prescribed to those who are malnourished or at risk of becoming malnourished. In this study, we reviewed previous studies to see if oral nutritional supplements (as a form of dietary support) work at reducing malnutrition in frail older adults and whether or not they are value for money. WHAT DID WE DO?: We searched for studies up to September 2021 on frail older people who were at risk of malnutrition or were malnourished in care homes, hospitals or the community in any country. We included studies that measured malnutrition and the consequences of malnutrition, quality of life, survival, costs and hospitalisations. We assessed the difference in malnutrition between those receiving oral nutritional supplements and those receiving usual care or other dietary (or nutritional) interventions. We also looked at the value for money of oral nutritional supplements. WHAT DID WE FIND?: We found 12 studies (11 studies looking at whether the supplements worked and one study looking at value for money). Most of which were of low quality, and many were funded by industry. Studies often did not report on longer-term effects, or how older people felt about the supplements. There was no clear or strong evidence that oral nutritional supplements worked or were value for money in reducing malnutrition or its consequences (such as the ability to perform everyday tasks). WHAT DOES THIS MEAN?: There is weak evidence for oral nutritional supplements in frail older adults. Future high-quality studies should be independent, assess longer-term effects, and have better reporting on factors that influence the impacts of oral nutritional supplements.

Effectiveness and cost-effectiveness of oral nutritional supplements in frail older people who are malnourished or at risk of malnutrition: a systematic review and meta-analysis.

BACKGROUND: Current management of malnutrition can include prescribed oral nutritional supplements (ONS); however, there is uncertainty whether these supplements are effective in people who are older (≥65 years) and frail. We assessed the effectiveness, cost-effectiveness, and adherence and acceptability of ONS in frail older people who are malnourished or at risk of malnutrition. METHODS: In this systematic review and meta-analysis, five bibliographic databases (MEDLINE, EMBASE, Cochrane Library, Scopus, and CINAHL) and grey literature sources were searched from inception to Sept 13, 2021, to identify studies assessing the effectiveness and cost-effectiveness of ONS (with or without other dietary interventions) in frail older people who are malnourished or at risk of malnutrition. Multiple reviewers independently did study screening, data extraction, and risk of bias assessment. Quality was assessed using version 1.0 of the Cochrane risk of bias tool for randomised controlled trials (RCTs), and the BMJ Drummond checklist was used to assess the quality of the included cost-effectiveness study. A meta-analysis was done for the effectiveness review; for the other reviews, a narrative synthesis approach was used. This systematic review and meta-analysis was registered on PROSPERO, CRD42020170906. FINDINGS: Of 8492 records retrieved and screened, we included 11 RCTs involving 822 participants, six of which were fully or partly funded by industry. For the majority of the outcomes for which meta-analyses were possible (11/12), Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) assessments suggested that the evidence was of very low certainty. Results suggested that ONS might have a slightly positive effect on energy (kcal) intake (standardised mean difference 1·02 [95% CI 0·15 to 1·88]; I2=87%; four studies), protein intake (standardised mean difference 1·67 [-0·03 to 3·37; I2=97%; four studies), and mobility (mean difference 0·03 [0·02 to 0·04]; I2=0%; four studies), compared with standard care. Narrative syntheses suggested that the effect of ONS on quality of life, compared with standard care, was mixed. In the identified studies, there was very little information related to active components, determinants, or acceptability of interventions. One economic evaluation, done in a care home setting, showed that ONS could be cost-effective. INTERPRETATION: We found little evidence of ONS reducing malnutrition or its associated adverse outcomes in older people who are frail. High-quality, non-industry-funded, adequately powered studies reporting on short-term and long-term health outcomes, determinants, and participant characteristics are needed. FUNDING: UK National Institute of Health and Care Research (NIHR) Health Technology Assessment (NIHR128729).

PROtein enriched MEDiterranean diet to combat undernutrition and promote healthy neuroCOGnitive ageing in older adults: The PROMED-COG consortium project.

Dementia is a major public health challenge owing to its increasing prevalence and recognised impact on disability among older adults. Observational data indicate that weight loss is associated with increased dementia risk of 30%-40% and precedes a diagnosis of cognitive impairment or dementia by at least one decade. Although relatively little is known about the mechanisms of unintentional weight loss in dementia, this provides a window of opportunity to intervene with strategies to counteract undernutrition and delay, or prevent, the onset of dementia. This article provides an overview of the PROMED-COG project and associated work packages. The project aimes to (1) strengthen the epidemiologic evidence to better understand the potential benefits of combating undernutrition for healthy neurocognitive ageing; (2) increase scientific knowledge on the balance between a protein enriched Mediterranean diet (PROMED) and physical exercise to prevent undernutrition and promote healthy neurocognitive ageing, and generate data on mechanistic pathways; (3) stimulate collaboration and capacity building for nutrition and neurocognitive ageing research in Europe; and (4) develop public and practice recommendations to combat undernutrition and promote healthy neurocognitive ageing in older adults. Findings will provide new and critical insights into the role of undernutrition in neurocognitive ageing, how this role can differ by sex, genetic risk and timing of undernutrition exposure, and how modifications of dietary and physical activity behaviour can reduce the burden of undernutrition and neurodegeneration. The research outcomes will be useful to inform policy and practice about the dietary guidelines of older people and provide insight to industry for the development of food-based solutions to prevent undernutrition.

Meeting report: plant-rich dietary patterns and health.

Dietary patterns (DP) rich in plant foods are associated with improved health and reduced non-communicable disease risk. In October 2021, the Nutrition Society hosted a member-led conference, held online over 2 half days, exploring the latest research findings examining plant-rich DP and health. The aim of the present paper is to summarise the content of the conference and synopses of the individual speaker presentations are included. Topics included epidemiological analysis of plant-rich DP and health outcomes, the effects of dietary interventions which have increased fruit and vegetable (FV) intake on a range of health outcomes, how adherence to plant-rich DP is assessed, the use of biomarkers to assess FV intake and a consideration of how modifying behaviour towards increased FV intake could impact environmental outcomes, planetary health and food systems. In conclusion, although there are still considerable uncertainties which require further research, which were considered as part of the conference and are summarised in this review, adopting a plant-rich DP at a population level could have a considerable impact on diet and health outcomes, as well as planetary health.

Associations Between Dietary Patterns and Neuroimaging Markers: A Systematic Review.

Dementia is a complex, growing challenge for population health worldwide. Dietary patterns (DPs) may offer an opportunity to beneficially influence cognitive ageing and potentially reduce an individuals' risk of dementia through diet-related mechanisms. However, previous studies within this area have shown mixed results, which may be partly explained by the lack of sensitivity and accuracy within cognitive testing methods. Novel neuroimaging techniques provide a sensitive method to analyse brain changes preceding cognitive impairment which may have previously remained undetected. The purpose of this systematic review was to elucidate the role of DPs in relation to brain ageing processes, by summarising current prospective and intervention studies. Nine prospective studies met the inclusion criteria for the review, seven evaluated the Mediterranean diet (MeDi), one evaluated the Alternative Healthy Eating Index-2010, and one evaluated a posteriori derived DPs. No intervention studies were eligible for inclusion in this review. There was some evidence of an association between healthy DPs and neuroimaging markers including changes within these markers over time. Consequently, it is plausible that better adherence to such DPs may positively influence brain ageing and neurodegeneration. Future studies may benefit from the use of multi-modal neuroimaging techniques, to further investigate how adherence to a DP influences brain health. The review also highlights the crucial need for further intervention studies within this research area.

Diet Patterns, the Gut Microbiome, and Alzheimer's Disease.

Given the complex bidirectional communication system that exists between the gut microbiome and the brain, there is growing interest in the gut microbiome as a novel and potentially modifiable risk factor for Alzheimer's disease (AD). Gut dysbiosis has been implicated in the pathogenesis and progression of AD by initiating and prolonging neuroinflammatory processes. The metabolites of gut microbiota appear to be critical in the mechanism of the gut-brain axis. Gut microbiota metabolites, such as trimethylamine-n-oxide, lipopolysaccharide, and short chain fatty acids, are suggested to mediate systemic inflammation and intracerebral amyloidosis via endothelial dysfunction. Emerging data suggest that the fungal microbiota (mycobiome) may also influence AD pathology. Importantly, 60% of variation in the gut microbiome is attributable to diet, therefore modulating the gut microbiome through dietary means could be an effective approach to reduce AD risk. Given that people do not eat isolated nutrients and instead consume a diverse range of foods and combinations of nutrients that are likely to be interactive, studying the effects of whole diets provides the opportunity to account for the interactions between different nutrients. Thus, dietary patterns may be more predictive of a real-life effect on gut microbiome and AD risk than foods or nutrients in isolation. Accumulating evidence from experimental and animal studies also show potential effects of gut microbiome on AD pathogenesis. However, data from human dietary interventions are lacking. Well-designed intervention studies are needed in diverse populations to determine the influence of diet on gut microbiome and inform the development of effective dietary strategies for prevention of AD.

The effect of animal versus plant protein on muscle mass, muscle strength, physical performance and sarcopenia in adults: protocol for a systematic review.

BACKGROUND: The evidence base for the role of dietary protein in maintaining good muscle health in older age is strong; however, the importance of protein source remains unclear. Plant proteins are generally of lower quality, with a less favourable amino acid profile and reduced bioavailability; therefore, it is possible that their therapeutic effects may be less than that of higher quality animal proteins. This review aims to evaluate the effectiveness of plant and animal protein interventions on muscle health outcomes. METHODS: A robust search strategy was developed to include terms relating to dietary protein with a focus on protein source, for example dairy, meat and soy. These were linked to terms related to muscle health outcomes, for example mass, strength, performance and sarcopenia. Five databases will be searched: MEDLINE, Scopus, Cochrane Central Register of Controlled Trials, Embase and Web of Science. Studies included will be randomised controlled trials with an adult population (≥ 18) living in the community or residential homes for older adults, and only English language articles will be included. Two independent reviewers will assess eligibility of individual studies. The internal validity of included studies will be assessed using Cochrane Risk of Bias 2.0 tool. Results will be synthesised in narrative format. Where applicable, standardised mean differences (SMD) (95% confidence interval [CI]) will be combined using a random-effects meta-analysis, and tests of homogeneity of variance will be calculated. DISCUSSION: Dietary guidelines recommend a change towards a plant-based diet that is more sustainable for health and for the environment; however, reduction of animal-based foods may impact protein quality in the diet. High-quality protein is important for maintenance of muscle health in older age; therefore, there is a need to understand whether replacement of animal protein with plant protein will make a significant difference in terms of muscle health outcomes. Findings from this review will be informative for sustainable nutritional guidelines, particularly for older adults and for those following vegan or vegetarian diets. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD420201886582.

Associations between depression and cognition, mild cognitive impairment and dementia in persons with diabetes mellitus: A systematic review and meta-analysis.

AIMS: This systematic review aimed to examine whether persons with diabetes and depression had poorer cognition and higher dementia risk than persons with diabetes only. Moreover, the impact of timing, frequency of depressive episodes throughout life, and antidepressant treatment were examined. METHODS: PubMed, Embase and PsycINFO were searched to obtain observational studies between August 2015 and June 2021 that examined the association between depression and cognition, mild cognitive impairment or dementia in people with diabetes. Studies published before August 2015 were retrieved from a previous systematic review. Findings were pooled using meta-analyses. RESULTS: 10 out of 19 included articles were appropriate for the meta-analyses. Persons with diabetes and depression experienced greater declines in executive function (SMD = -0.39 (-0.69, -0.08)), language (SMD = -0.80 (-1.52, -0.09)), memory (SMD = -0.63 (-1.12, -0.14)) and overall cognition (SMD = -0.77 (-1.33, -0.20)), and greater dementia risk (HR = 1.82 (1.79, 1.85)) than persons with diabetes only. No significant differences were observed for complex attention. No studies examined the role of timing and frequency of depressive episodes and antidepressant treatment. CONCLUSION: In persons with diabetes, depression is associated with worse cognition and higher dementia risk. The potential mitigating effect of antidepressant treatment remains unclear.

Food insecurity and brain health in adults: A systematic review.

Food insecurity has been associated with adverse effects on physical health and well-being in both high and low-income countries, but effects on brain health are not clear. The purpose of this systematic review was to determine the relationship between food insecurity and important brain health outcomes in adults including depression, stroke, cognitive impairment and dementia. Electronic databases were searched to find studies which investigated relations between food insecurity and predefined brain health outcomes. Thirty studies met the inclusion criteria for review of which 23 were conducted in high income countries and seven in low- or middle-income countries. Most studies (n = 24) were cross-sectional, five were prospective and 1 was a case-control design. Seven studies reporting outcomes relating to cognitive performance and 24 relating to depression. No studies investigated relations between food insecurity and stroke or dementia. There was substantial heterogeneity in the populations studied as well as measures of food insecurity and outcomes which made comparisons between studies difficult. Overall, the findings highlighted that individuals who were food insecure had increased likelihood of depressive symptoms and poorer global cognition than those who were food secure. It is possible that social support and food aid programmes attenuate the effects of food insecurity on depressive symptoms. Future research is needed to determine whether interventions to alleviate food insecurity can benefit brain health in vulnerable populations.