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Objectives: The PROtein-enriched MEDiterranean diet to combat undernutrition and promote healthy neuroCOGnitive ageing in older adults (PROMED-COG) is a European project that investigates the role of nutritional status on neurocognitive ageing. This methodological paper describes the harmonization process of dietary data from four Italian observational studies (Pro.V.A., ILSA, BEST-FU, and NutBrain). Methods: Portion sizes and food frequency consumption within different food frequency questionnaires were retrospectively harmonized across the datasets on daily food frequency, initially analyzing raw data using the original codebook and establishing a uniform food categorization system. Individual foods were then aggregated into 27 common food groups. Results: The pooled cohort consisted of 9326 individuals (40-101 years, 52.4% female). BEST-FU recruited younger participants who were more often smokers and less physically active than those of the other studies. Dietary instruments varied across the studies differing in the number of items and time intervals assessed, but all collected dietary intake through face-to-face interviews with a common subset of items. The average daily intakes of the 27 food groups across studies varied, with BEST-FU participants generally consuming more fruits, vegetables, red meat, and fish than the other studies. Conclusions: Harmonization of dietary data presents challenges but allows for the integration of information from diverse studies, leading to a more robust and statistically powerful dataset. The study highlights the feasibility and benefits of data harmonization, despite inherent limitations, and sets the stage for future research into the effects of diet on cognitive health and aging.

Data on the association of the Mediterranean diet (MD) with depressive symptoms in older people at high risk of depression are scarce. This study aimed to investigate the cross-sectional association of the adherence to the MD and its components with depressive symptoms in an Italian cohort of older men and women. A total of 325 men and 473 women aged 65–97 years (2019–2023) answered a 102-item semi-quantitative FFQ, which was used to calculate the Mediterranean diet score (MDS). Depressive symptoms were assessed using the Centre for Epidemiological Studies Depression Scale; subjects with a score of 16 or more were considered to have depression. Multivariable logistic regression was used for statistical analysis. The occurrence of depressive symptoms was 19·8 % (8·0 % men, 27·9 % women). High adherence to MDS (highest tertile) significantly reduced the odds of having depressive symptoms by 54·6 % (OR 0·454, 95 % CI 0·266, 0·776). In sex-stratified analysis, the reduction was evident in women (OR 0·385, 95 % CI 0·206, 0·719) but not in men (OR 0·828, 95 % CI 0·254, 2·705). Looking at the association of MDS components with depressive symptoms, we found an inverse significant association with fish consumption and the MUFA:SFA ratio above the median only in women (OR 0·444, 95 % CI 0·283, 0·697 and OR 0·579, 95 % CI 0·345, 0·971, respectively). High adherence to the MDS, and a high fish intake and MUFA:SFA ratio were associated with lower depressive symptoms in women only. Future longitudinal studies are needed to confirm these findings and to explore the underlying biological mechanisms.

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)., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY. Published by BMJ.)

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.

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., (© 2022 The Authors. Nutrition Bulletin published by John Wiley & Sons Ltd on behalf of British Nutrition Foundation.)

Introduction: Decline in physical function varies substantially across older individuals due to several extrinsic modifiable factors such as dietary patterns, physical activity and social support. We aimed to determine the association of these factors and their interaction with mobility and muscle strength decline., Methods: We analyzed data from 1686 functionally healthy individuals aged 60 + from the population-based Swedish National study on Aging and Care in Kungsholmen (SNAC-K). The Mediterranean Diet Score (MDS) was calculated based on a validated food frequency questionnaire. Self-reported physical activity was categorized based on current recommendations, and social support was measured according to participants' perceived material and psychological support from relatives and friends. Participants' physical function was assessed over 12 years through changes in walking speed (m/s) and chair stand time (s). Linear mixed models adjusted for socio-demographic and clinical factors were used. In order to explore the combined effect of the different exposures, two indicator variables were created by cross-classifying individuals' levels of Mediterranean diet adherence and social support or physical activity., Results: Participants with a high adherence to Mediterranean diet were primarily < 78 years (82.3%), women (56.1%), married (61.1%), with university education (52.8%), high levels of social support (39.3%) and health-enhancing levels of physical activity (51.5%). A one-point increase in MDS (score range 0-9) was associated with less annual deterioration in walking speed (β*time[year] = 0.001; p = 0.024) and chair-stand time (β*time[year] = -0.014; p = 0.008). The potential protective effect of Mediterranean diet was highest among participants reporting high social support (β*time[year] = -0.065, p = 0.026 for chair stands) and high physical activity (β*time[year] = 0.010, p = 0.001 for walking speed), beyond the effect of each exposure individually., Conclusion: A higher adherence to Mediterranean diet, especially in combination with recommended levels of physical activity and high social support, may contribute to delay the decline in physical function observed with aging., (© 2021. The Author(s).)

The aim of the present analysis was to evaluate the association of the Mediterranean diet (MeDi), smoking habits and physical activity with all-cause mortality in an Italian population during a 20-year follow-up study. A total of 1693 subjects aged 40-74 who enrolled in the study in 1991-5 were asked about dietary and other lifestyle information at baseline. Adherence to the MeDi was evaluated by the Mediterranean dietary score (MedDietScore). A healthy lifestyle score was computed by assigning 1 point each for a medium or high adherence to the MedDietScore, non-smoking and physical activity. Cox models were used to assess the associations between lifestyle factors and healthy lifestyle scores and all-cause mortality, adjusting for potential confounders. The final sample included 974 subjects with complete data and without chronic disease at baseline. During a median of 17·4 years of follow-up, 193 people died. Subjects with high adherence to the MedDietScore (hazard ratio (HR) 0·62, 95 % CI 0·43, 0·89)), non-smokers (HR 0·71, 95 % CI 0·51, 0·98) and physically active subjects (HR 0·55, 95 % CI 0·36, 0·82) were at low risk of death. Each point increase in the MedDietScore was associated with a significant 5 % reduction of death risk. Subjects with 1, 2 or 3 healthy lifestyle behaviours had a significantly 39, 56, and 73 % reduced risk of death, respectively. A high adherence to MeDi, non-smoking and physical activity were strongly associated with a reduced risk of all-cause mortality in healthy subjects after long-term follow-up. This reduction was even stronger when the healthy lifestyle behaviours were combined.