Effect of the Mediterranean diet on cognition and brain morphology and function: a systematic review of randomized controlled trials

Food resources and kitchen skills plus aerobic training (FoRKS+) for black adults with hypertension: A pilot trial protocol

BACKGROUND

Midlife hypertension is associated with cognitive decline and Alzheimer's disease and related dementia (ADRD), suggesting that blood pressure control may be a therapeutic target for dementia prevention. Given excess hypertension in non-Hispanic Black (NHB) adults, blood pressure control may also reduce ADRD disparities. We describe a pilot randomized controlled trial (RCT) to evaluate the feasibility and preliminary efficacy of a multicomponent lifestyle-based intervention versus enhanced usual care on cognition among middle-aged NHB adults.

METHODS AND STUDY DESIGN

The Food Resources and Kitchen Skills plus Aerobic Training (FoRKS+) study is a 2-arm, single-blinded trial that compares those receiving the FoRKS+ program (target N = 64) versus those receiving enhanced usual care (target N = 64) in local federally-qualified health centers. Key eligibility criteria include self-identified NHB adults between ages 35-75 with a mean systolic blood pressure ≥ 130 mm/Hg obtained from 24-h ambulatory blood pressure monitoring. The FoRKS+ program includes 5 weeks of hypertension self-management courses, 11 weeks of nutrition courses, and 12 weeks of aerobic training in dietitian and health coach-led virtual groups. We will collect data on primary cognitive outcomes, feasibility, hypothesized intervention mediators and moderators, and demographic and health covariates at baseline, near intervention weeks 16-, and 28 (primary outcome assessment), and week 52 follow-up. We will use mixed-effects modeling to examine intervention effects on cognition.

DISCUSSION

This pilot RCT will examine the feasibility and preliminary effects of a multicomponent lifestyle intervention on cognitive function in NHB adults, which may have implications for reducing health disparities in ADRD.

Dietary inflammatory index and neuropsychiatric disorders

Neuropsychiatric disorders (NPDs) are considered a potential threat to mental health. Inflammation predominantly plays a role in the pathophysiology of NPDs. Dietary patterns are widely postulated to be involved in the physiological response to inflammation. This review aims to discuss the literature on how dietary inflammatory index (DII) is related to inflammation and, consequently, NPDs. After comprehensive scrutiny in different databases, the articles that investigated the relation of DII score and various NPDs and psychological circumstances were included. The association between dietary patterns and mental disorders comprising depression, anxiety, and stress proved the role of a proinflammatory diet in these conditions' exacerbation. Aging is another condition closely associated with DII. The impact of proinflammatory and anti-inflammatory diet on sleep quality indicated related disorders like sleep latency and day dysfunctions among the different populations are in relation with the high DII score. The potential effects of genetic backgrounds, dietary patterns, and the gut microbiome on DII are discussed as well. To plan preventive or therapeutic interventions considering the DII, these factors, especially genetic variations, should be considered as there is a growing body of literature indicating the role of personalized medicine in different NPDs. To the best of our knowledge, there is a limited number of RCTs on this subject, so future research should evaluate the causality via RCTs and look for therapeutic interventions with an eye on personalized medicine using information about DII in NPDs.

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.

Knowledge, Attitudes, and Behaviours Concerning the Mediterranean Diet Among Older Adults in Australia

Despite the growing body of evidence demonstrating the positive health effects of the Mediterranean diet, it is not routinely recommended in practice and adherence is low in the general population in Australia. The knowledge-attitude-behaviour model explains how health behaviours are supported through a process of acquiring knowledge, developing attitudes, and forming behaviours. Evidence has suggested that having a high level of nutrition-related knowledge is associated with more positive attitudes, which is directly linked to positive dietary behaviours. However, reports of knowledge and attitudes towards the Mediterranean diet, and how these directly relate to behaviours in older adults, are lacking. This study explored Mediterranean diet-related knowledge, attitudes, and behaviours among community-dwelling older adults in Australia. Participants were adults aged 55 years and older who completed an online survey that contained three parts: (a) knowledge - Mediterranean Diet Nutrition Knowledge Questionnaire (Med-NKQ); (b) nutrition-related attitudes and behaviours, and barriers and enablers to dietary change; (c) demographics. The sample included 61 adults who ranged in age from 55 to 89 years. The overall knowledge score was 30.5 out of a possible 40 points, with 60.7% classified as having a high level of knowledge. Knowledge was lowest for nutrient content and label reading. Attitudes and behaviours were generally positive and were not associated with level of knowledge. The most common barriers to dietary change were perceived cost and lack of knowledge, and motivational factors. There are a number of key gaps in knowledge that should be addressed through targeted educational programs. Strategies and tools to overcome perceived barriers and improve self-efficacy are needed to facilitate positive dietary behaviours.

Nourishing the Cognition with Millets: A Comprehensive Review of Their Nutritional Impact and Potential as Cognitive Enhancers

Cognition is the mental processes and abilities involved in acquiring, storing, retrieving and using it for decision making. Cognitive decline due to aging, lifestyle factor, chronic health conditions, genetic, and environmental factors are rising global concern and propose a potential threat to the cognitive health. The nutritional imbalance has led to increase in cognitive disorders around the world. Millets can be a nutritional intervention for promoting cognitive health and preventing cognitive decline. Millets has abundant phenolic compounds, flavonoids, and antioxidants to protect against oxidative stress-induced cognitive impairment. Millets exert neuroprotective effects by modulating pathways involved in neuronal-survival, synaptic-plasticity, and release of brain-derived neurotrophic factor. Millets demonstrates anti-inflammatory properties by regulating inflammatory-pathways and suppressing cytokines associated with cognitive impairment. Millets maintain healthy gut microbiota by producing metabolites such as short-chain fatty acids, which influence brain function and cognition. However, further research is needed to elucidate the underlying mechanisms and on optimizing the proportion do exploit its potential. Implementing millet-based dietary strategies through public health initiatives and educational programs can be a practical approach to support cognitive health across populations. Harnessing the potential of millets as a nutritional intervention offers a promising avenue for promoting cognitive health and improving the quality of life.

APOE-Genotype and Insulin Modulate Estimated Effect of Dietary Macronutrients on Cognitive Performance: Panel Analyses in Nondiabetic Older Adults at Risk of Dementia

BACKGROUND

The apolipoprotein E gene (APOE ε-2/3/4, combined as 6 different genotypes: ε-22/23/24/33/34/44) and insulin status modulate dementia risk and play a role in the metabolism of macronutrients.

OBJECTIVES

We aimed to examine APOE-genotype and fasting insulin as effect modifiers of the slopes between dietary macronutrients and cognitive performance among older adults at risk of dementia.

METHODS

Panel analyses-with diet and cognition measured at baseline and follow-up at years 1 and 2-were performed in a sub-sample from the FINGER (Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability) trial (n = 676, 60-77 y, 46% females, all nondiabetics). The associations between macronutrients (3-d food records, z-scores) and global cognition (modified Neuropsychological Test Battery, z-score) were analyzed in mixed regression models adjusted for confounders selected a priori. After a gradient was implied by the point estimates in categorical APOE analyses, we investigated a continuous APOE variable [APOE-gradient, coded -1 (for ε-23), -0.5 (ε-24), 0 (ε-33), 1 (ε-34), 2 (ε-44)] as an effect-modifier.

RESULTS

At increasing levels of the APOE-gradient, a relatively more favorable slope between diet and cognition was observed for a lower carbohydrate/fat ratio [β = -0.040, 95% confidence interval (CI): -0.074, -0.006; P = 0.020 for interaction diet × APOE-gradient), and higher protein (β = 0.075, 95% CI: 0.042, 0.109; P = 9.4 × 10-6). Insulin concentration (log-linear) modulated the association between the carbohydrate/fat ratio and cognition by a quadratic interaction (β = -0.016, P = 0.039). Coherent findings for exploratory predictors (fiber, fat subtypes, composite score, metabolic biomarkers) were compatible with published hypotheses of differential dietary adaptation by APOE, with cognition among ε-33 being relatively independent of dietary parameters-implying "metabolic flexibility." Antagonistic slopes to cognition for ε-23 (positive) compared with ε-34 and ε-44 (negative) were found for a Higher-carbohydrates-fiber-Lower-fat-protein composite score, even as within-subjects effects.

CONCLUSIONS

APOE-based precision nutrition appears conceptually promising, but replications in wider samples are warranted, as well as support from trials. Both relative hyper- and hypoinsulinemia might modulate the effect of diet on cognition.

Effects of the multidomain intervention with nutritional supplements on cognition and gut microbiome in early symptomatic Alzheimer's disease: a randomized controlled trial

Background

The SoUth Korean study to PrEvent cognitive impaiRment and protect BRAIN health through lifestyle intervention in at-risk elderly people (SUPERBRAIN) is a part of the World-Wide Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (WW-FINGERS) network. This study aimed to demonstrate the effects of the SUPERBRAIN-based multidomain intervention with nutritional supplements in amyloid positive emission tomography (PET) proven early symptomatic Alzheimer's disease patients.

Methods

Forty-six participants who were diagnosed with mild cognitive impairment or mild dementia and were positive in the amyloid PET study randomized into three groups: group A, the multidomain intervention with nutritional supplements; group B, nutritional supplements only; and a control group. The primary outcome was a change in the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) total scale index score after an 8-week intervention. Secondary outcomes, including gut microbiome data, were also analyzed.

Results

The RBANS total scale index score improved significantly in group A compared with group B (p < 0.032) and compared with the control group (p < 0.001). After intervention, beta diversity of the gut microbiome between group A and the control group increased, and patients in group A were more enriched with Bifidobacterium.

Conclusion

SUPERBRAIN-based multidomain intervention with nutritional supplements improves cognition and gut microbiota in patients with early symptomatic Alzheimer's disease who were amyloid-positive by PET.

Scientific evidence supporting the newly developed one-health labeling tool "Med-Index": an umbrella systematic review on health benefits of mediterranean diet principles and adherence in a planeterranean perspective

BACKGROUND

Med-Index is a one-health front-of-pack (FOP) label, based on Mediterranean diet (MedDiet) principles, developed to summarize information about the nutritional properties and related-health benefits of any food as well as its sustainable production processes, and the associated food company's social responsibility parameters in a new "Planeterranean" perspective. Thus, Med-Index can be adopted in and by any European region and authority as well as worldwide; this is achieved by consumption and cooking of locally available and sourced foods that respect MedDiet principles, both in terms of healthy nutrition and sustainable production. The huge body of scientific evidence about the health benefits of the MedDiet model and principles requires a comprehensive framework to encompass the scientific reliability and robustness of this tool. A systematic review was carried out to examine the association between human health and adherence to MedDiet patterns upon which the "Med-Index" tool was subsequently developed.

METHODS

MEDLINE and PubMed databases were searched for eligible publications from 1990 to April 2023. Systematic literature reviews, with or without meta-analysis, of clinical trials and observational studies were screened by two independent investigators for eligibility, data extraction, and quality assessment. English language and the time interval 1990-2023 were applied. A registry code CRD42023464807 was generated on PROSPERO and approved for this search protocol. The corrected covered area (CCA), calculated to quantify the degree of overlap between reviews, gave a slight overlap (CCA = 4%).

RESULTS

A total of 84 systematic reviews out of 6681 screened records were selected. Eligible reviews included studies with predominantly observational designs (61/84, 72.6%%), of which 26/61 referenced studies of mixed observational and RCT designs, while 23/84 (27.4%) were RCT-only systematic reviews. Seventy-nine different entries were identified for health outcomes, clustered into 10 macro-categories, each reporting a statistically significant association with exposure to the MedDiet. Adherence to MedDiet was found to strongly benefit age-related chronic diseases (21.5%), neurological disorders (19%), and obesity-related metabolic features (12.65), followed by CVDs (11.4%), cancer (10.1%), diabetes (7.5%), liver health (6.3%), inflammation (5%), mortality (5%), and renal health (1.2%). The quality of the studies was moderate to high.

CONCLUSION

In the context of a "Planeterranean" framework and perspective that can be adopted in any European region and worldwide, MedDiet represents a healthy and sustainable lifestyle model, able to prevent several diseases and reduce premature mortality. In addition, the availability of a FOP, such as Med-Index, might foster more conscious food choices among consumers, paying attention both to human and planetary health.

Dietary pattern, food, and nutritional supplement effects on cognitive outcomes in mild cognitive impairment: a systematic review of previous reviews

CONTEXT

Nutritional interventions may benefit cognition in people with mild cognitive impairment (MCI). However, evidence is yet to be synthesized in a way that can inform recommendations for clinical and public health settings.

OBJECTIVE

To systematically review evidence on the effect of dietary patterns, foods, and nutritional supplements on cognitive decline in individuals with MCI.

DATA SOURCES

Guided by the Preferred Reporting items for Systematic Review and Meta-Analysis Protocols 2015 statement, the Medline, EMBASE, and CINAHL databases, the JBI Database of Systematic Reviews and Implementation Reports, Cochrane Database of Systematic Reviews, and Database of Abstracts of Reviews of Effects were searched (publication years 2005 to 2020). Included studies were English-language systematic reviews and meta-analyses of randomized controlled trials and cohort studies reporting on the effectiveness of nutritional interventions on cognition of individuals with MCI.

DATA EXTRACTION

Two reviewers independently selected studies and extracted data on cognitive outcomes and adverse events. Review quality was assessed using AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews-2). Primary study overlap was managed following Cochrane Handbook guidelines.

DATA ANALYSIS

Of the 6677 records retrieved, 20 reviews were included, which, in turn, reported on 43 randomized controlled trials and 1 cohort study that, together, addressed 18 nutritional interventions. Most reviews were limited by quality and the small number of primary studies with small sample sizes. Reviews were mostly positive for B vitamins, omega-3 fatty acids, and probiotics (including 12, 11 and 4 primary studies, respectively). Souvenaid and the Mediterranean diet reduced cognitive decline or Alzheimer's disease progression in single trials with <500 participants. Findings from studies with a small number of participants suggest vitamin D, a low-carbohydrate diet, medium-chain triglycerides, blueberries, grape juice, cocoa flavanols, and Brazil nuts may improve individual cognitive subdomains, but more studies are needed.

CONCLUSIONS

Few nutritional interventions were found to convincingly improve cognition of individuals with MCI. More high-quality research in MCI populations is required to determine if nutritional treatments improve cognition and/or reduce progression to dementia.

SYSTEMATIC REVIEW REGISTRATION

Open Science Framework protocol identifier DOI:10.17605/OSF.IO/BEP2S.

Dietary Habits and Gaming Behaviors of Portuguese and Brazilian Esports Players

As the esports industry grows, marketing campaigns for fast food, soft drinks, alcoholic and energy drinks, and dietary supplements at related events intensify. Portuguese and Brazilian esports players' dietary patterns remain unexplored. This study aimed to characterize the dietary and gaming habits of esports players. We applied an anonymous, open online survey to a convenience sample of esports players that included the PREDIMED and the Internet Gaming Disorder Scale. The survey was shared through email and social media platforms, including Facebook, Twitter, Instagram, Discord, WhatsApp, and Twitch. The sample (n = 579) was predominantly male (91.4%), averaged 26.1 (SD = 7.0) years, and 25.9 (SD = 5.5) kg/m2. Most reported a weak (53.7%) adherence to the Mediterranean diet. Almost a third (32.3%) consumed dietary supplements. Our sample presented a low adhesion to the Mediterranean dietary pattern, low consumption of fruit and vegetables, and high consumption of fast food, red and processed meat, soft drinks, and dietary supplements, including caffeine-based supplements. Dietary supplement consumption was related to a higher adhesion to the Mediterranean diet, and a higher level of professionalization and internet gaming disorder correlated with a lower adhesion. In conclusion, we infer that Portuguese and Brazilian esports players follow an unbalanced diet.

Understanding the impact of radical changes in diet and the gut microbiota on brain function and structure: rationale and design of the EMBRACE study

BACKGROUND

Bariatric surgery leads to profound changes in gut microbiota and dietary patterns, both of which may interact to impact gut-brain communication. Though cognitive function improves postsurgery, there is a large variability in outcomes. How bariatric surgery-induced modifications in the gut microbiota and dietary patterns influence the variability in cognitive function is still unclear.

OBJECTIVES

To elucidate the associations between bariatric surgery-induced changes in dietary and gut microbiota patterns with cognition and brain structure.

SETTING

University hospital.

METHODS

A total of 120 adult patients (≥30 years) scheduled to undergo a primary bariatric surgery along with 60 age-, sex-, and body mass index-matched patients on the surgery waitlist will undergo assessments 3-months presurgery and 6- and 12-month postsurgery (or an equivalent time for the waitlist group). Additionally, 60 age-and sex-matched nonbariatric surgery eligible individuals will complete the presurgical assessments only. Evaluations will include sociodemographic and health behavior questionnaires, physiological assessments (anthropometrics, blood-, urine-, and fecal-based measures), neuropsychological cognitive tests, and structural magnetic resonance imaging. Cluster analyses of the dietary and gut microbiota changes will define the various dietary patterns and microbiota profiles, then using repeated measures mixed models, their associations with global cognitive and structural brain alterations will be explored.

RESULTS

The coordinating study site (Centre intégré universitaire de santé et de services sociaux du Nord-de-l'Île-de-Montréal, QC, Canada), provided the primary ethical approval (Research Ethics Board#: MP-32-2022-2412).

CONCLUSIONS

The insights generated from this study can be used to develop individually-targeted neurodegenerative disease prevention strategies, as well as providing critical mechanistic information.

Trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons

BACKGROUND

Findings from observational studies suggest that dietary patterns may offer protective benefits against cognitive decline, but data from clinical trials are limited. The Mediterranean-DASH Intervention for Neurodegenerative Delay, known as the MIND diet, is a hybrid of the Mediterranean diet and the DASH (Dietary Approaches to Stop Hypertension) diet, with modifications to include foods that have been putatively associated with a decreased risk of dementia.

METHODS

We performed a two-site, randomized, controlled trial involving older adults without cognitive impairment but with a family history of dementia, a body-mass index (the weight in kilograms divided by the square of the height in meters) greater than 25, and a suboptimal diet, as determined by means of a 14-item questionnaire, to test the cognitive effects of the MIND diet with mild caloric restriction as compared with a control diet with mild caloric restriction. We assigned the participants in a 1:1 ratio to follow the intervention or the control diet for 3 years. All the participants received counseling regarding adherence to their assigned diet plus support to promote weight loss. The primary end point was the change from baseline in a global cognition score and four cognitive domain scores, all of which were derived from a 12-test battery. The raw scores from each test were converted to z scores, which were averaged across all tests to create the global cognition score and across component tests to create the four domain scores; higher scores indicate better cognitive performance. The secondary outcome was the change from baseline in magnetic resonance imaging (MRI)-derived measures of brain characteristics in a nonrandom sample of participants.

RESULTS

A total of 1929 persons underwent screening, and 604 were enrolled; 301 were assigned to the MIND-diet group and 303 to the control-diet group. The trial was completed by 93.4% of the participants. From baseline to year 3, improvements in global cognition scores were observed in both groups, with increases of 0.205 standardized units in the MIND-diet group and 0.170 standardized units in the control-diet group (mean difference, 0.035 standardized units; 95% confidence interval, -0.022 to 0.092; P = 0.23). Changes in white-matter hyperintensities, hippocampal volumes, and total gray- and white-matter volumes on MRI were similar in the two groups.

CONCLUSIONS

Among cognitively unimpaired participants with a family history of dementia, changes in cognition and brain MRI outcomes from baseline to year 3 did not differ significantly between those who followed the MIND diet and those who followed the control diet with mild caloric restriction. (Funded by the National Institute on Aging; ClinicalTrials.gov number, NCT02817074.).

The association of dietary approaches to stop hypertension (DASH) and Mediterranean diet with mental health, sleep quality and chronotype in women with overweight and obesity: a cross-sectional study

PURPOSE

Mental and sleep disorders are global public health problems, especially in Middle Eastern countries, and are significantly associated with circadian rhythm. This study sought to investigate the association between the dietary approaches to stop hypertension (DASH) and Mediterranean diet scores and mental health, sleep quality, and circadian rhythm.

METHODS

We enrolled 266 overweight and obese women, and depression, anxiety, and stress scale (DASS) score, Pittsburgh Sleep Quality Index (PSQI), and Morning-Evening Questionnaire (MEQ), were assessed. The Mediterranean and DASH diet score was measured using a validated semi-quantitative Food Frequency Questionnaire (FFQ). The physical activity was evaluated using the International Physical Activity Questionnaire (IPAQ). Analysis of variance and analysis of covariance, chi-square, and multinomial logistic regression tests were used as appropriate.

RESULTS

Our results showed that there was a significant inverse association between adherence to the Mediterranean diet and mild and moderate anxiety scores (p < 0.05). In addition, there was an inverse association between adherence to the DASH diet and the risk of severe depression and extremely severe stress scores (p < 0.05). Moreover, higher adherence to both dietary scores was associated with good sleep quality (p < 0.05). There was a significant relationship between circadian rhythm and the DASH diet (p < 0.05).

CONCLUSION

A significant association exists between a DASH and Mediterranean diet with sleep status, mental health, and chronotype in women of childbearing age with obesity and overweight.

LEVEL OF EVIDENCE

Level V, Cross-sectional observational study.

Diet and lifestyle impact the development and progression of Alzheimer's dementia

Dementia is a growing public health concern, with an estimated prevalence of 57 million adults worldwide. Alzheimer's disease (AD) accounts for 60-80% of the cases. Clinical trials testing potential drugs and neuroprotective agents have proven futile, and currently approved drugs only provide symptomatic benefits. Emerging epidemiological and clinical studies suggest that lifestyle changes, including diet and physical activity, offer an alternative therapeutic route for slowing and preventing cognitive decline and dementia. Age is the single most common risk factor for dementia, and it is associated with slowing cellular bioenergetics and metabolic processes. Therefore, a nutrient-rich diet is critical for optimal brain health. Furthermore, type 2 diabetes (T2D) is a risk factor for AD, and diets that reduce the risk of T2D may confer neuroprotection. Foods predominant in Mediterranean, MIND, and DASH diets, including fruits, leafy green vegetables, fish, nuts, and olive oil, may prevent or slow cognitive decline. The mechanisms by which these nutrients promote brain health, however, are not yet completely understood. Other dietary approaches and eating regimes, including ketogenic and intermittent fasting, are also emerging as beneficial for brain health. This review summarizes the pathophysiology, associated risk factors, and the potential neuroprotective pathways activated by several diets and eating regimes that have shown promising results in promoting brain health and preventing dementia.

Impact of Nut Consumption on Cognition across the Lifespan

Cognitive health is a life-long concern affected by modifiable risk factors, including lifestyle choices, such as dietary intake, with serious implications for quality of life, morbidity, and mortality worldwide. In addition, nuts are a nutrient-dense food that contain a number of potentially neuroprotective components, including monounsaturated and polyunsaturated fatty acids, fiber, B-vitamins, non-sodium minerals, and highly bioactive polyphenols. However, increased nut consumption relates to a lower cardiovascular risk and a lower burden of cardiovascular risk factors that are shared with neurodegenerative disorders, which is why nuts have been hypothesized to be beneficial for brain health. The present narrative review discusses up-to-date epidemiological, clinical trial, and mechanistic evidence of the effect of exposure to nuts on cognitive performance. While limited and inconclusive, available evidence suggests a possible role for nuts in the maintenance of cognitive health and prevention of cognitive decline in individuals across the lifespan, particularly in older adults and those at higher risk. Walnuts, as a rich source of the plant-based polyunsaturated omega-3 fatty acid alpha-linolenic acid, are the nut type most promising for cognitive health. Given the limited definitive evidence available to date, especially regarding cognitive health biomarkers and hard outcomes, future studies are needed to better elucidate the impact of nuts on the maintenance of cognitive health, as well as the prevention and management of cognitive decline and dementia, including Alzheimer disease.

The Role of Vascular Risk Factors in Cognitive Impairment and Dementia and Prospects for Prevention

One of the most challenging clinical expressions of population aging is cognitive impairment and dementia. Among risk factors for the development of dementia, modifiable vascular risk factors have emerged as contributors to both vascular and nonvascular types of dementia. Epidemiologic studies have been particularly informative in understanding the link between vascular risks and dementia across the life course. We discuss vascular risks for dementia and cognitive impairment and practical management recommendations.

Mediterranean diet related metabolite profiles and cognitive performance

BACKGROUND & AIMS

Evidence suggests that adherence to the Mediterranean diet (MedDiet) affects human metabolism and may contribute to better cognitive performance. However, the underlying mechanisms are not clear.

OBJECTIVE

We generated a metabolite profile for adherence to MedDiet and evaluated its cross-sectional association with aspects of cognitive performance.

METHODS

A total of 1250 healthy Greek middle-aged adults from the Epirus Health Study cohort were included in the analysis. Adherence to the MedDiet was assessed using the 14-point Mediterranean Diet Adherence Screener (MEDAS); cognition was measured using the Trail Making Test, the Verbal Fluency test and the Logical Memory test. A targeted metabolite profiling (n = 250 metabolites) approach was applied, using a high-throughput nuclear magnetic resonance platform. We used elastic net regularized regressions, with a 10-fold cross-validation procedure, to identify a metabolite profile for MEDAS. We evaluated the associations of the identified metabolite profile and MEDAS with cognitive tests, using multivariable linear regression models.

RESULTS

We identified a metabolite profile composed of 42 metabolites, mainly lipoprotein subclasses and fatty acids, significantly correlated with MedDiet adherence (Pearson r = 0.35, P-value = 5.5 × 10^-37). After adjusting for known risk factors and accounting for multiple testing, the metabolite profile and MEDAS were not associated with the cognitive tests.

CONCLUSIONS

A plasma metabolite profile related to better adherence to the MedDiet was not associated with the tested aspects of cognitive performance, in a middle-aged Mediterranean population.

Analysis of associations between dietary patterns, genetic disposition, and cognitive function in data from UK Biobank

PURPOSE

Research suggests that diet influences cognitive function and the risk for neurodegenerative disease. The present study aimed to determine whether a recently developed diet score, based on recommendations for dietary priorities for cardio metabolic health, was associated with fluid intelligence, and whether these associations were modified by individual genetic disposition.

METHODS

This research has been conducted using the UK Biobank Resource. Analyses were performed using self-report data on diet and the results for the verbal-numerical reasoning test of fluid intelligence of 104,895 individuals (46% male: mean age at recruitment 57.1 years (range 40-70)). For each participant, a diet score and a polygenic score (PGS) were constructed, which evaluated predefined cut-offs for the intake of fruit, vegetables, fish, processed meat, unprocessed meat, whole grain, and refined grain, and ranged from 0 (unfavorable) to 7 (favorable). To investigate whether the diet score was associated with fluid intelligence, and whether the association was modified by PGS, linear regression analyses were performed.

RESULTS

The average diet score was 3.9 (SD 1.4). After adjustment for selected confounders, a positive association was found between baseline fluid intelligence and PGS (P < 0.001). No association was found between baseline fluid intelligence and diet score (P = 0.601), even after stratification for PGS, or in participants with longitudinal data available (n = 9,482).

CONCLUSION

In this middle-aged cohort, no evidence was found for an association between the investigated diet score and either baseline or longitudinal fluid intelligence. However, as in previous reports, fluid intelligence was strongly associated with a PGS for general cognitive function.

Dietary Tyrosine Intake (FFQ) Is Associated with Locus Coeruleus, Attention and Grey Matter Maintenance: An MRI Structural Study on 398 Healthy Individuals of the Berlin Aging Study-II

BACKGROUND AND OBJECTIVE

It is documented that low protein and amino-acid dietary intake is related to poorer cognitive health and increased risk of dementia. Degradation of the neuromodulatory pathways, (comprising the cholinergic, dopaminergic, serotoninergic and noradrenergic systems) is observed in neurodegenerative diseases and impairs the proper biosynthesis of key neuromodulators from micro-nutrients and amino acids. How these micro-nutrients are linked to neuromodulatory pathways in healthy adults is less studied. The Locus Coeruleus-Noradrenergic System (LC-NA) is the earliest subcortical structure affected in Alzheimer's disease, showing marked neurodegeneration, but is also sensitive for age-related changes. The LC-NA system is critical for supporting attention and cognitive control, functions that are enhanced both by tyrosine administration and chronic tyrosine intake. The purpose of this study was to 1) investigate whether the dietary intake of tyrosine, the key precursor for noradrenaline (NA), is related to LC signal intensity 2) whether LC mediates the reported association between tyrosine intake and higher cognitive performance (measured with Trail Making Test - TMT), and 3) whether LC signal intensity relates to an objective measure of brain maintenance (BrainPAD).

METHODS

The analyses included 398 3T MRIs of healthy participants from the Berlin Aging Study II to investigate the relationship between LC signal intensity and habitual dietary tyrosine intake-daily average (HD-Tyr-IDA - measured with Food Frequency Questionnaire - FFQ). As a control procedure, the same analyses were repeated on other main seeds of the neuromodulators' subcortical system (Dorsal and Medial Raphe, Ventral Tegmental Area and Nucleus Basalis of Meynert). In the same way, the relationships between the five nuclei and BrainPAD were tested.

RESULTS

Results show that HD-Tyr-IDA is positively associated with LC signal intensity. Similarly, LC disproportionally relates to better brain maintenance (BrainPAD). Mediation analyses reveal that only LC, relative to the other nuclei tested, mediates the relationship between HD-Tyr-IDA I and performance in the TMT and between HD-Tyr-IDA and BrainPAD.

CONCLUSIONS

These findings provide the first evidence linking tyrosine intake with LC-NA system signal intensity and its correlation with neuropsychological performance. This study strengthens the role of diet for maintaining brain and cognitive health and supports the noradrenergic theory of cognitive reserve. Within this framework, adequate tyrosine intake might increase the resilience of LC-NA system functioning, by preventing degeneration and supporting noradrenergic metabolism required for LC function and neuropsychological performance.

Association between the mediterranean diet and cognitive health among healthy adults: A systematic review and meta-analysis

Background

An increasing prevalence of cognitive disorders warrants comprehensive systematic reviews on the effect of diet on cognitive health. Studies have suggested that the Mediterranean (MeDi) diet has protective effects against metabolic diseases. However, comprehensive systematic reviews on the effect of the MeDi diet on the cognitive decline are limited. We investigated whether adherence to the MeDi diet could lower the risk of the cognitive disorder or improve cognitive function in older adults.

Methods

In this systematic review and meta-analysis, PubMed, Web of Science, PsycINFO, Scopus, and Cochrane databases were searched from inception to June 2021. Cohort studies and randomized controlled trials (RCTs) were included. The effect sizes were estimated as log risk ratios and standard mean differences (SMDs) with 95% confidence intervals (CIs). The Newcastle–Ottawa score and Cochrane Collaboration’s tool were used to assess the risk of bias in cohort studies and RCTs, respectively.

Results

Of the 1,687 screened studies, 31 cohort studies and five RCTs met the eligibility criteria for qualitative analysis; 26 cohort studies and two RCTs were included in the meta-analysis. In the cohort studies, high adherence to the MeDi diet was associated with lower risk of mild cognitive impairment (MCI) [risk ratio (RR) = 0.75 (0.66–0.86)], and Alzheimer’s disease (AD) [RR = 0.71 (0.56–0.89)]. In the RCTs, high adherence to the MeDi diet was associated with better episodic [SMD = 0.20 (0.09–0.30)] and working memories [SMD = 0.17 (0.01–0.32)] than lowest group.

Conclusion

Adherence to the MeDi diet may reduce the risk of MCI and AD. However, other associations with cognitive outcomes (global cognition, working memory, and episodic memory) remain open to interpretation. Overall, the MeDi diet is recommended to prevent or delay cognitive disorders and improve cognitive function. Further, long-term RCTs are warranted to strengthen the evidence.

Systematic review registration

[https://www.crd.york.ac.uk], identifier [CRD42021276801].

Higher dietary diversity and better healthy aging: A 4-year study of community-dwelling middle-aged and older adults from the Taiwan Longitudinal Study of Aging

OBJECTIVES

To investigate the relationship between dietary diversity and healthy aging (in terms of mobility performance, physical functions, cognitive functions, and depressive symptoms) among community-dwelling middle-aged and older adults by using a nationally representative population-based cohort study.

METHODS

Data from 3213 study participants in the Taiwan Longitudinal Study on Aging (TLSA) were retrieved for analysis, and all participants were divided into five groups according to the quintile of dietary variety scores (DVSs). In the 4-year follow-up study, multivariate logistic regression models were applied to investigate the associations between DVS subgroups and declines in mobility performance, physical function (activities of daily living (ADLs) and instrumental activities of daily living (IADLs)), cognitive function and depressive symptoms.

RESULTS

In this study, the DVS quintile identified people who were significantly vulnerable in diet quality. Among those in the lowest DVS quintile, the proportions consuming seafood, eggs, and beans/legumes per week were 0.3 %, 7.8 % and 12.6 %, respectively, while among those in the highest DVS quintile, the proportions were 40.2 %, 83.1 %, and 82.7 %, respectively. "Inverse" dose-response associations were observed between the DVS and the risks of decline in mobility performance, physical function (ADLs and IADLs), cognitive function, and depressive symptoms. These risks decreased with the higher DVS quintile group as compared to the lowest DVS quintile group. Even after adjustments for demographics, health behaviors (e.g., physical activity) and comorbidities, participants in the highest DVS quintile group were still associated with the lowest risk of decline in ADLs (adjusted odds ratio (aOR) 0.59 [95 % confidence interval (CI) 0.37-0.94], p < 0.05) and IADLs (aOR 0.53 [0.39-0.73], p < 0.01). However, no such association was observed in the risk of worsened mobility performance, cognitive function and depressive symptoms.

CONCLUSIONS

In conclusion, higher dietary diversity has protective effects in declines in multidimensional outcomes associated with healthy aging, particularly physical (ADL and IADL) functions, among community-dwelling middle-aged and older adults. Intervention studies are needed to confirm the causal relationships between dietary diversity and healthy aging.

Diet quality interventions to prevent neurocognitive decline: a systematic review and meta-analysis

OBJECTIVE

To determine the impact of diet quality interventions on neurocognitive decline in older adults.

DESIGN

Four databases were searched (Medline, EMBASE, CENTRAL and PsycINFO) for randomised controlled trials involving diet quality interventions and cognitive outcomes in older adults. Study quality was assessed using the Cochrane Risk of Bias tool. Outcomes selected for meta-analysis were memory and executive function, for which standardised mean differences (SMD) were calculated. Subgroup and sensitivity analyses were undertaken to explore causes of heterogeneity. Additional outcomes of global cognitive function, incident dementia, attention, language/verbal fluency, and processing speed were narratively synthesised.

RESULTS

Twelve studies were included, investigating the Mediterranean, Dietary Approaches to Stop Hypertension and Nordic diets. Risk of bias varied across studies. Dietary intervention had a significant effect on memory (SMD: 0.98; 95% CI: 0.39, 1.57; p = 0.001) and executive function (SMD: 2.02; 95% CI: 1.04, 3.01; p < 0.00001), although neither outcome was significant in sensitivity analyses. Heterogeneity was high (I² = 99%) prior to sensitivity analyses and low (I² = 0%) after. Results for narratively synthesised cognitive measures were inconsistent with no clear direction of effect.

CONCLUSION

The current body of evidence would suggest the effect of dietary intervention on neurocognitive decline in older adults is unclear given the considerable heterogeneity and bias present across studies. These findings should be interpreted with consideration to the limited number of studies that could be included and the large variation in study designs. Further randomised controlled trials with harmonised cognitive outcomes and assessments are needed to clarify direction of effect.

Exercise Effects on Cognition in Older African Americans: A Pilot Randomized Trial

Introduction

Regular physical activity lowers risk for cognitive decline and neurodegenerative disorders. Older African Americans (AAs) have been underrepresented in trials that increased physical activity to improve cognitive outcomes.

Methods

56 sedentary, older, cognitively healthy AAs (avg. 69.2 ± 3.4 yrs. old) were randomized in 1:1 ratio into either a 12-week successful aging group (SAG) or a 12-week physical activity group (PAG). Participants in SAG attended weekly 60-min educational sessions in which healthy aging topics were discussed. Participants in PAG attended supervised physical activity sessions twice per week at local YMCAs (90–120 min/week) and were prescribed 2–3 days per week of home-based activity. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) assessed cognitive function. ANCOVA models compared mean 12-week change in global cognition and subdomain scores between groups with secondary analyses for sex differences. Effect sizes for RBANS were calculated.

Results

The RBANS global cognition score (SAG Est. 5.6 ± 1.8, effect size = 0.37, p = 0.003) and several subdomain scores (one-sample T tests, all p < 0.05) increased significantly within the SAG. Scores for global cognition increased more in SAG than in PAG (Change Estimate, PAG minus SAG: –4.6 ± 2.5 points, effect size = 0.31) at a trend level (p = 0.072). SAG females increased their global cognition score more than PAG females and more than males in either PAG or SAG (all p < 0.035).

Discussion

A 12-week physical activity intervention (PAG) did not improve cognitive functioning among older AAs but a comparator healthy aging education program did. Inadequate physical activity dosage or duration, SAG members acting on health-related information from educational sessions, and/or social stimulation within the SAG may have contributed to these results. Future studies should combine socially engaging activities with vigorous physical activity for cognitive enhancement among cognitively healthy older African Americans.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier NCT03474302.

Oxidative Stress Mediates the Association Between Dietary Fat Intake and Cognition in US Older Adults

OBJECTIVE

Dietary fat intake was considered as a modifiable factor influencing cognitive performance. The objective was to 1) examine the associations between different types of dietary fat intakes and cognitive outcomes among elder adults (≥60 years old); 2) assess whether peripheral oxidative stress and antioxidant biomarkers are potential mediators of dietary fat intake and cognitive impairment relationship.

METHODS

Using data from National Health and Nutrition Examination Survey 2011-2014, total fat, saturated fatty acid (SFAT), monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), cholesterol, ω-3 and ω-6 fatty acids were used to evaluate dietary fat intakes. Cognitive outcomes were assessed by word learning and recall modules from the consortium to establish a registry for Alzheimer's Disease (CERAD), animal fluency test, and digit symbol substitution test (DSST). Antioxidant biomarkers were assessed by gamma glutamyl transpeptidase (GGT), bilirubin, uric acid, and vitamin D levels. Linear regression models and causal mediation analysis were applied to quantify the associations.

RESULTS

A total of 2,253 elder adults were included in the data analyses. Dietary intake of PUFA and ω-6 fatty acid were positively associated with DSST [β (95% CI): 0.06 (0.01,0.10), t statistic = 2.39, df= 2238, p = 0.02; β (95% CI): 0.06 (0.01,0.11), t statistic = 2.54, df= 2238, p = 0.01, respectively]. GGT was negatively associated with DSST [β (95% CI): -0.04 (-0.07, -0.01), t statistic = -2.73, df= 2239, p = 0.01], whereas uric acid was positively associated with CERAD total score [β (95% CI): 0.04 (0.00,0.08), t statistic = 2.03, df= 2233, p = 0.04]. The association between dietary intake of PUFA/ω -3/ω -6 and DSST performance was partially mediated by GGT level.

CONCLUSION

Our findings support that PUFAs in dietary sources were associated with lower risks for cognitive impairment partially via lowering oxidative stress. Dietary PUFA supplementation may potentially reduce risk of cognitive impairment via antioxidative mechanism.

Are clinical trials randomising households to lifestyle interventions to delay cognitive decline feasible? A pilot study to determine the beliefs, preferences, and deterrents for households impacted by dementia based on semi-structured interviews

Introduction

While lifestyle risk factors are implicated in the development and progression of cognitive impairment, interventional trials of individual participants have yielded unconvincing evidence. We sought to explore the development of lifestyle interventions targeting the household-unit.

Methods

Semi-structured interviews were carried out among eight households affected by cognitive impairment (i.e. member of the household had cognitive impairment). Interviews took place online using a secure, web-based video platform recommended for patient clinician interaction. Interview content was analysed, and important themes identified.

Results

Eighteen participants were interviewed within households, of which eight (one per household) had cognitive impairment and others were spouses or first-degree relatives living in the same home. Several themes emerged; 1) household members without cognitive impairment were more likely to report poor sleep habits, and sleep was perceived to be the hardest behaviour to change; 2) diet generated most interest as a potential lifestyle intervention target as most participants believed there is a strong link with nutrition and cognition; 3) physical activity is challenging to adapt due to lack of motivation and focus when individuals are cognitively impaired. Barriers to study participation, including risk of harm, complexity of intervention and deviation from routine emerged during discussions.

Conclusions

This study identified beliefs and preferences of households towards lifestyle intervention trials. Findings from this study may be used to inform future clinical trial protocols and future qualitative studies should explore acceptability and feasibility of digital intervention applications.

Adherence to Life's Simple 7 and Cognitive Function Among Older Adults: The National Health and Nutrition Examination Survey 2011 to 2014

Background

The American Heart Association proposed the Life’s Simple 7 (LS7; including diet, physical activity, smoking, body mass index, blood pressure, plasma fasting glucose, total cholesterol) to promote cardiovascular health. Adherence to LS7 has been found to be associated with better cognitive health as well, but the generalizability of previous studies is limited. We aimed to examine the associations of adherence to LS7 and cognitive function among older adults in a nationally representative sample of population.

Methods and Results

A total of 2585 older adults (≥60 years, 54% female, 80% non‐Hispanic White) in the National Health and Nutrition Examination Survey 2011 to 2014 were included for analysis. Components of LS7 were measured, and adherence to LS7 was calculated on the basis of established cutoff points of individual components. Cognitive function was examined using the Consortium to Establish a Registry for Alzheimer’s Disease Word List Memory Task (immediate and delayed memory), Digit Symbol Substitution Test (DSST), and Animal Fluency Test. Test‐specific and global cognition Z scores were created. Multivariable linear regression models were conducted on the associations of adherence to LS7 with domain‐specific and global cognition Z scores. Each incremental point in adherence to LS7 was associated with higher Z scores for global cognition (β=0.05; 95% CI, 0.02–0.07), Digit Symbol Substitution Test (β=0.05; 95% CI, 0.03–0.07), Consortium to Establish a Registry for Alzheimer’s Disease Word Learning subtest immediate memory (β=0.03; 95% CI, 0.004–0.05), and animal fluency test (β=0.05; 95% CI, 0.02–0.07).

Conclusions

Greater adherence to LS7 metrics is associated with better cognitive function among older US adults in a nationally representative sample of population.

Can dietary patterns prevent cognitive impairment and reduce Alzheimer's disease risk: exploring the underlying mechanisms of effects

Alzheimer's disease (AD) is one of the fastest growing cognitive decline-related neurological diseases. To date, effective curative strategies have remained elusive. A growing body of evidence indicates that dietary patterns have significant effects on cognitive function and the risk of developing AD. Previous studies on the association between diet and AD risk have mainly focused on individual food components and specific nutrients, and the mechanisms responsible for the beneficial effects of dietary patterns on AD are not well understood. This article provides a comprehensive overview of the effects of dietary patterns, including the Mediterranean diet (MedDiet), dietary approaches to stop hypertension (DASH) diet, Mediterranean-DASH diet intervention for neurological delay (MIND), ketogenic diet, caloric restriction, intermittent fasting, methionine restriction, and low-protein and high-carbohydrate diet, on cognitive impairment and summarizes the underlying mechanisms by which dietary patterns attenuate cognitive impairment, especially highlighting the modulation of dietary patterns on cognitive impairment through gut microbiota. Furthermore, considering the variability in individual metabolic responses to dietary intake, we put forward a framework to develop personalized dietary patterns for people with cognitive disorders or AD based on individual gut microbiome compositions.

Metabolic Syndrome, Cognitive Impairment and the Role of Diet: A Narrative Review

Background: This narrative review presents the association between metabolic syndrome (MetS), along with its components, and cognition-related disorders, as well as the potential reversal role of diet against cognitive impairment by modulating MetS. Methods: An electronic research in Medline (Pubmed) and Scopus was conducted. Results: MetS and cognitive decline share common cardiometabolic pathways as MetS components can trigger cognitive impairment. On the other side, the risk factors for both MetS and cognitive impairment can be reduced by optimizing the nutritional intake. Clinical manifestations such as dyslipidemia, hypertension, diabetes and increased central body adiposity are nutrition-related risk factors present during the prodromal period before cognitive impairment. The Mediterranean dietary pattern stands among the most discussed predominantly plant-based diets in relation to cardiometabolic disorders that may prevent dementia, Alzheimer’s disease and other cognition-related disorders. In addition, accumulating evidence suggests that the consumption of specific dietary food groups as a part of the overall diet can improve cognitive outcomes, maybe due to their involvement in cardiometabolic paths. Conclusions: Early MetS detection may be helpful to prevent or delay cognitive decline. Moreover, this review highlights the importance of healthy nutritional habits to reverse such conditions and the urgency of early lifestyle interventions.

The effect of a high-polyphenol Mediterranean diet (Green-MED) combined with physical activity on age-related brain atrophy: the Dietary Intervention Randomized Controlled Trial Polyphenols Unprocessed Study (DIRECT PLUS)

BACKGROUND

The effect of diet on age-related brain atrophy is largely unproven.

OBJECTIVES

We aimed to explore the effect of a Mediterranean diet (MED) higher in polyphenols and lower in red/processed meat (Green-MED diet) on age-related brain atrophy.

METHODS

This 18-mo clinical trial longitudinally measured brain structure volumes by MRI using hippocampal occupancy score (HOC) and lateral ventricle volume (LVV) expansion score as neurodegeneration markers. Abdominally obese/dyslipidemic participants were randomly assigned to follow 1) healthy dietary guidelines (HDG), 2) MED, or 3) Green-MED diet. All subjects received free gym memberships and physical activity guidance. Both MED groups consumed 28 g walnuts/d (+440 mg/d polyphenols). The Green-MED group consumed green tea (3-4 cups/d) and Mankai (Wolffia-globosa strain, 100 g frozen cubes/d) green shake (+800 mg/d polyphenols).

RESULTS

Among 284 participants (88% men; mean age: 51 y; BMI: 31.2 kg/m2; APOE-ε4 genotype = 15.7%), 224 (79%) completed the trial with eligible whole-brain MRIs. The pallidum (-4.2%), third ventricle (+3.9%), and LVV (+2.2%) disclosed the largest volume changes. Compared with younger participants, atrophy was accelerated among those ≥50 y old (HOC change: -1.0% ± 1.4% compared with -0.06% ± 1.1%; 95% CI: 0.6%, 1.3%; P < 0.001; LVV change: 3.2% ± 4.5% compared with 1.3% ± 4.1%; 95% CI: -3.1%, -0.8%; P = 0.001). In subjects ≥ 50 y old, HOC decline and LVV expansion were attenuated in both MED groups, with the best outcomes among Green-MED diet participants, as compared with HDG (HOC: -0.8% ± 1.6% compared with -1.3% ± 1.4%; 95% CI: -1.5%, -0.02%; P = 0.042; LVV: 2.3% ± 4.7% compared with 4.3% ± 4.5%; 95% CI: 0.3%, 5.2%; P = 0.021). Similar patterns were observed among younger subjects. Improved insulin sensitivity over the trial was the parameter most strongly associated with brain atrophy attenuation (P < 0.05). Greater Mankai, green tea, and walnut intake and less red and processed meat were significantly and independently associated with reduced HOC decline (P < 0.05). Elevated urinary concentrations of the polyphenols urolithin-A (r = 0.24; P = 0.013) and tyrosol (r = 0.26; P = 0.007) were significantly associated with lower HOC decline.

CONCLUSIONS

A Green-MED (high-polyphenol) diet, rich in Mankai, green tea, and walnuts and low in red/processed meat, is potentially neuroprotective for age-related brain atrophy.This trial was registered at clinicaltrials.gov as NCT03020186.

Risk Factors, Lifestyle Behaviors, and Vascular Brain Health

Although a relationship between traditional cardiovascular risk factors and stroke has long been recognized, these risk factors likely play a role in other aspects of brain health. Clinical stroke is only the tip of the iceberg of vascular brain injury that includes covert infarcts, white matter hyperintensities, and microbleeds. Furthermore, an individual's risk for not only stroke but poor brain health includes not only these traditional vascular risk factors but also lifestyle and genetic factors. The purpose of this narrative review is to summarize the state of the evidence on traditional and nontraditional vascular risk factors and their contributions to brain health. Additionally, we will review important modifiers that interact with these risk factors to increase, or, in some cases, reduce risk of adverse brain health outcomes, with an emphasis on genes and biomarkers associated with Alzheimer disease. Finally, we will consider the importance of social determinants of health in brain health outcomes.

Mediterranean diet score is associated with greater allocentric processing in the EPAD LCS cohort: A comparative analysis by biogeographical region

Background: Adherence to the Mediterranean diet (MedDiet), a primarily plant-based eating pattern, has been associated with lower dementia incidence. Much of the research has focused on Alzheimer's disease (AD) dementia and mild cognitive impairment (MCI), with less research looking at the preclinical symptomatically silent stages that pre-empt MCI and AD dementia. Although there is evidence from studies conducted globally, no studies have compared the effects of the MedDiet within and outside of the Mediterranean region in one cohort. Methods: Our study explored cross-sectional and longitudinal associations between MedDiet and cognition in the pan-European EPAD LCS, comparing those living within and outside of the Mediterranean region (as classified by European Union biogeographical definitions). After deriving MEDAS scores to quantify adherence to the MedDiet, we used linear regression and linear mixed effects models to test for associations between the MEDAS score and cognitive function measured by the Four Mountains Test (FMT) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). We additionally calculated MEDAS continuous and PYRAMID scores to provide alternative measures of MedDiet adherence. Results: We included 1826 participants, mean age 65.69 (±7.42) years, majority female (56.2%) with family history (65.8%) and minority APOEε4 carriers (38.9%). Higher MEDAS scores were associated with better performance on the FMT both cross-sectionally (n = 1,144, ß: -0.11, SE: 0.04, p = 0.007) and longitudinally (slope: 0.10, 95% CI: 0.04-0.17, p: 0.002). The effect was marginally greater in the Mediterranean region in the cross-sectional analysis, with a stronger effect emerging longitudinally. In exploratory analyses, the association between MEDAS and FMT scores was only seen in female participants. A sensitivity analysis excluding Toulouse and Perugia, as cities near, but not within, the biogeographical region, found significant associations between higher MEDAS and MEDAS continuous scores, and a number of RBANS total and index scores. Conclusion: MedDiet adherence is associated with better FMT scores, with effects seen most strongly in the Mediterranean region from longitudinal data. Our sensitivity analysis suggested a more global cognitive benefit of MedDiet adherence. This study highlights the need to further explore for whom and for what brain health outcomes the MedDiet confers benefit. This evidence would identify a window of opportunity in the life-course to maximise the benefit and better inform public health campaigns and patient-level interventions.

Mediterranean, DASH, and MIND Dietary Patterns and Cognitive Function: The 2-Year Longitudinal Changes in an Older Spanish Cohort

Background and Aims: Plant-forward dietary patterns have been associated with cardiometabolic health benefits, which, in turn, have been related to cognitive performance with inconsistent findings. The objective of this study was to examine the relationship between baseline adherence to three a priori dietary patterns (Mediterranean, DASH, and MIND diets) with 2-year changes in cognitive performance in older adults with overweight or obesity and high cardiovascular disease risk. Methods: A prospective cohort analysis was conducted within the PREDIMED-Plus trial, involving 6,647 men and women aged 55-75 years with overweight or obesity and metabolic syndrome. Using a validated, semiquantitative 143-item food frequency questionnaire completed at baseline, the dietary pattern adherence scores were calculated. An extensive neuropsychological test battery was administered at baseline and 2-year follow-up. Multivariable-adjusted linear regression models were used to assess associations between 2-year changes in cognitive function z-scores across tertiles of baseline adherence to the a priori dietary patterns. Results: Adherence to the Mediterranean diet at baseline was associated with 2-year changes in the general cognitive screening Mini-Mental State Examination (MMSE, β: 0.070; 95% CI: 0.014, 0.175, P-trend = 0.011), and two executive function-related assessments: the Trail Making Tests Part A (TMT-A, β: -0.054; 95% CI: -0.110, - 0.002, P-trend = 0.047) and Part B (TMT-B, β: -0.079; 95% CI: -0.134, -0.024, P-trend = 0.004). Adherence to the MIND diet was associated with the backward recall Digit Span Test assessment of working memory (DST-B, β: 0.058; 95% CI: 0.002, 0.114, P-trend = 0.045). However, higher adherence to the DASH dietary pattern was not associated with better cognitive function over a period of 2 years. Conclusion: In older Spanish individuals with overweight or obesity and at high cardiovascular disease risk, higher baseline adherence to the Mediterranean dietary pattern may be associated with better cognitive performance than lower adherence over a period of 2 years.

Nutrition and cognition across the lifetime: an overview on epigenetic mechanisms

The functioning of our brain depends on both genes and their interactions with environmental factors. The close link between genetics and environmental factors produces structural and functional cerebral changes early on in life. Understanding the weight of environmental factors in modulating neuroplasticity phenomena and cognitive functioning is relevant for potential interventions. Among these, nutrition plays a key role. In fact, the link between gut and brain (the gut-brain axis) is very close and begins in utero, since the Central Nervous System (CNS) and the Enteric Nervous System (ENS) originate from the same germ layer during the embryogenesis. Here, we investigate the epigenetic mechanisms induced by some nutrients on the cognitive functioning, which affect the cellular and molecular processes governing our cognitive functions. Furthermore, epigenetic phenomena can be positively affected by specific healthy nutrients from diet, with the possibility of preventing or modulating cognitive impairments. Specifically, we described the effects of several nutrients on diet-dependent epigenetic processes, in particular DNA methylation and histones post-translational modifications, and their potential role as therapeutic target, to describe how some forms of cognitive decline could be prevented or modulated from the early stages of life.

Healthy Diet for Healthy Aging

Extending healthspan is a major public health challenge. Diet is one of the modifiable factors for preventing age-related diseases and preserving overall good health status during aging. Optimizing individuals’ intrinsic capacity, including domains in cognition, psychological, sensory function, vitality, and locomotion, has been proposed as a model of healthy aging by the World Health Organization. To better understand the relationships between a healthy diet and healthy aging, this review summarizes the recent epidemiologic and clinical data for dietary patterns that have been shown to play a role in (domains of) healthy aging. Regardless of priori or posteriori dietary patterns, it appears that dietary patterns centered on plant-based foods have a beneficial role in (domains of) healthy aging. Our review identified a knowledge gap in dietary patterns and multidimensional concepts of healthy aging. More epidemiological studies should consider intrinsic capacity as an outcome measure to further our understanding of a healthy diet and multidimensional concepts of healthy aging. When a sufficient number of epidemiological studies is available, evidence can be synthesized and clinical trials can be designed to evaluate a healthy diet as a strategy for healthy aging to further our progress in translating evidence to practice and promoting healthy aging.

Mediterranean diet and cognitive function: From methodology to mechanisms of action

The traditional Mediterranean diet (MedDiet), rich in minimally processed plant foods and fish, has been widely recognized to be one of the healthiest diets. Data from multiple randomized clinical trials have demonstrated its powerful effect against oxidative stress, inflammation and the development and progression of cardiovascular disease, type 2 diabetes, and other metabolic conditions that play a crucial role in the pathogenesis of neurodegenerative diseases. The protecting effects of the MedDiet against cognitive decline have been investigated in several observational and experimental studies. Data from observational studies suggest that the MedDiet may represent an effective dietary strategy for the early prevention of dementia, although these findings require further substantiation in clinical trials which have so far produced inconclusive results. Moreover, as we discuss in this review, accumulating data emphasizes the importance of: 1) maintaining an optimal nutritional and metabolic status for the promotion of healthy cognitive aging, and 2) implementing cognition-sparing dietary and lifestyle interventions during early time-sensitive windows before the pathological cascades turn into an irreversible state. In summary, components of the MedDiet pattern, such as essential fatty acids, polyphenols and vitamins, have been associated with reduced oxidative stress and the current evidence from observational studies seems to assign to the MedDiet a beneficial role in promoting brain health; however, results from clinical trials have been inconsistent. While we advocate for longitudinal analyses and for larger and longer clinical trials to be conducted, we assert our interim support to the use of the MedDiet as a protective dietary intervention for cognitive function based on its proven cardiovascular and metabolic benefits.

Nutrition, Physical Activity, and Other Lifestyle Factors in the Prevention of Cognitive Decline and Dementia

Multiple factors combined are currently recognized as contributors to cognitive decline. The main independent risk factor for cognitive impairment and dementia is advanced age followed by other determinants such as genetic, socioeconomic, and environmental factors, including nutrition and physical activity. In the next decades, a rise in dementia cases is expected due largely to the aging of the world population. There are no hitherto effective pharmaceutical therapies to treat age-associated cognitive impairment and dementia, which underscores the crucial role of prevention. A relationship among diet, physical activity, and other lifestyle factors with cognitive function has been intensively studied with mounting evidence supporting the role of these determinants in the development of cognitive decline and dementia, which is a chief cause of disability globally. Several dietary patterns, foods, and nutrients have been investigated in this regard, with some encouraging and other disappointing results. This review presents the current evidence for the effects of dietary patterns, dietary components, some supplements, physical activity, sleep patterns, and social engagement on the prevention or delay of the onset of age-related cognitive decline and dementia.

Development of the First WHO Guidelines for Risk Reduction of Cognitive Decline and Dementia: Lessons Learned and Future Directions

The first WHO guidelines for risk reduction of cognitive decline and dementia marked an important milestone in the field of dementia prevention. In this paper, we discuss the evidence reviewed as part of the guidelines development and present the main themes emerged from its synthesis, to inform future research and policies on dementia risk reduction. The role of intervention effect-size; the mismatch between observational and intervention-based evidence; the heterogeneity of evidence among intervention trials; the importance of intervention duration; the role of timing of exposure to a certain risk factor and interventions; the relationship between intervention intensity and response; the link between individual risk factors and specific dementia pathologies; and the need for tailored interventions emerged as the main themes. The interaction and clustering of individual risk factors, including genetics, was identified as the overarching theme. The evidence collected indicates that multidomain approaches targeting simultaneously multiple risk factors and tailored at both individual and population level, are likely to be most effective and feasible in dementia risk reduction. The current status of multidomain intervention trials aimed to cognitive impairment/dementia prevention was also briefly reviewed. Primary results were presented focusing on methodological differences and the potential of design harmonization for improving evidence quality. Since multidomain intervention trials address a condition with slow clinical manifestation—like dementia—in a relatively short time frame, the need for surrogate outcomes was also discussed, with a specific focus on the potential utility of dementia risk scores. Finally, we considered how multidomain intervention could be most effectively implemented in a public health context and the implications world-wide for other non-communicable diseases targeting common risk factors, taking into account the limited evidence in low-middle income countries. In conclusion, the evidence from the first WHO guidelines for risk reduction of cognitive decline and dementia indicated that “one size does not fit all,” and multidomain approaches adaptable to different populations and individuals are likely to be the most effective. Harmonization in trial design, the use of appropriate outcome measures, and sustainability in large at-risk populations in the context of other chronic disorders also emerged as key elements.

Quality of Life and a Surveillant Endocannabinoid System

The endocannabinoid system (ECS) is an important brain modulatory network. ECS regulates brain homeostasis throughout development, from progenitor fate decision to neuro- and gliogenesis, synaptogenesis, brain plasticity and circuit repair, up to learning, memory, fear, protection, and death. It is a major player in the hypothalamic-peripheral system-adipose tissue in the regulation of food intake, energy storage, nutritional status, and adipose tissue mass, consequently affecting obesity. Loss of ECS control might affect mood disorders (anxiety, hyperactivity, psychosis, and depression), lead to drug abuse, and impact neurodegenerative (Alzheimer's, Parkinson, Huntington, Multiple, and Amyotrophic Lateral Sclerosis) and neurodevelopmental (autism spectrum) disorders. Practice of regular physical and/or mind-body mindfulness and meditative activities have been shown to modulate endocannabinoid (eCB) levels, in addition to other players as brain-derived neurotrophic factor (BDNF). ECS is involved in pain, inflammation, metabolic and cardiovascular dysfunctions, general immune responses (asthma, allergy, and arthritis) and tumor expansion, both/either in the brain and/or in the periphery. The reason for such a vast impact is the fact that arachidonic acid, a precursor of eCBs, is present in every membrane cell of the body and on demand eCBs synthesis is regulated by electrical activity and calcium shifts. Novel lipid (lipoxins and resolvins) or peptide (hemopressin) players of the ECS also operate as regulators of physiological allostasis. Indeed, the presence of cannabinoid receptors in intracellular organelles as mitochondria or lysosomes, or in nuclear targets as PPARγ might impact energy consumption, metabolism and cell death. To live a better life implies in a vigilant ECS, through healthy diet selection (based on a balanced omega-3 and -6 polyunsaturated fatty acids), weekly exercises and meditation therapy, all of which regulating eCBs levels, surrounded by a constructive social network. Cannabidiol, a diet supplement has been a major player with anti-inflammatory, anxiolytic, antidepressant, and antioxidant activities. Cognitive challenges and emotional intelligence might strengthen the ECS, which is built on a variety of synapses that modify human behavior. As therapeutically concerned, the ECS is essential for maintaining homeostasis and cannabinoids are promising tools to control innumerous targets.

Relationship between the Risk of Gastric Cancer and Adherence to the Mediterranean Diet According to Different Estimators. MCC-Spain Study

Simple Summary

Dietary habits are one of the factors that influence the development of gastric cancer and, although it has been seen that the Mediterranean diet has a protective effect on this type of cancer, there are different indexes to assess the degree of adherence to this dietary pattern; this implies differences in the results obtained in the reduction of risk. The aim of this work was to assess the effect of adherence to the Mediterranean diet, measured with five different indexes, on the risk of gastric cancer.

Abstract

The aim was to assess the effect of adherence to the Mediterranean Diet, measured with five different indexes, on the risk of gastric cancer. Data come from the multicase-control study MCC—Spain, which included 354 gastric cancer cases and 3040 controls with data on diet. We used five indexes to evaluate adherence to the Mediterranean diet and assess the association between each pattern with the risk of gastric cancer, using multivariate logistic regression. The analyses were performed for the whole set of gastric cancer cases, by anatomical location (cardia and non-cardia) and by histological type (intestinal and diffuse). According to the used index, a high adherence protects one from gastric cancer (between 48% (aOR = 0.52; CI 95% = 0.28–0.94) and 75% (aOR = 0.25; CI 95% = 0.12–0.52)), from non-cardia (between 48% (aOR = 0.52; CI 95% = 0.36–0.75) and 65% (aOR = 0.35; CI 95% = 0.23–0.52)), and from the intestinal type (between 41% (aOR = 0.59; CI 95% = 0.36–0.95) and 72% (aOR = 0.28; CI 95% = 0.16–0.50)), but not from the diffuse type. In conclusion, high adherence to a Mediterranean diet pattern is a protective factor for the risk of gastric cancer, with greater adherence leading to greater protection.

Adherence to Mediterranean Diet and Cognitive Abilities in the Greek Cohort of Epirus Health Study

The Mediterranean diet is commonly proposed as a major modifiable protective factor that may delay cognitive impairment in the elderly. The aim of the study was to investigate the cross-sectional association of adherence to the Mediterranean diet with cognitive abilities in a younger Greek population. A total of 1201 healthy adults aged 21-77 years (mean: 47.8) from the Epirus Health Study cohort were included in the analysis. Adherence to the Mediterranean diet was measured using the 14-point Mediterranean Diet Adherence Screener (MEDAS) and cognition was measured using the Trail Making Test, the Verbal Fluency test and the Logical Memory test. Statistical analysis was performed using multiple linear regression models adjusted for age, sex, education, body mass index, smoking status, alcohol consumption and physical activity. Overall, no association was found between the MEDAS score and cognitive tests, which could be explained by the young mean age and high level of education of the participants. Future studies should target young and middle-aged individuals to gain further understanding of the association between Mediterranean diet and cognition in this age group.

Territorial and Sustainable Healthy Diets

The rapid changes that societies have gone through in the last few decades have led to the increase in the prevalence of malnutrition in all its forms and to the degradation of natural resources and the environment. The change in the dietary habits and production systems are responsible for much of this change. Some territorial diets have been shown as potentially capable of reversing these trends by positively contributing to the health of people and the environment such as the Mediterranean Diet and the New Nordic Diet. In this paper, we review the contribution of these 2 diets to health and nutrition and to environmental, sociocultural, and economic sustainability proposing pertinent indicators. Learning from a culturally established diet and a constructed one, tradeoff could be reached to ensure better health and sustainability outcomes. Strong factors for achieving this goal lie in building on the sociocultural appropriation of diets, having the proper tools and indicators, investing in cross-sector collaboration and policy coherence, and having the necessary political support to push the agenda of sustainability forward.

Interplay between cognition and weight reduction in individuals following a Mediterranean Diet: Three-year follow-up of the PREDIMED-Plus trial

BACKGROUND & AIMS

Some cognitive profiles might facilitate successful weight loss and its maintenance. Also, weight reductions may result in cognitive benefits. However, little work to date has examined the interactions between cognition and weight changes in the context of interventions with the Mediterranean diet (MedDiet). We studied the within-subject longitudinal relationships between cognition, body mass index (BMI), physical activity (PA), and quality of life (QoL), in older adults following a MedDiet.

METHODS

The PREDIMED-Plus is a primary prevention trial testing the effect of a lifestyle intervention program with an energy-restricted MedDiet (er-MedDiet), weight-loss goals and PA promotion on cardiovascular disease. The PREDIMED-Plus-Cognition sub-study included 487 participants (50% women, mean age 65.2 ± 4.7 years), with overweight/obesity, metabolic syndrome and normal cognitive performance at baseline. A comprehensive neurocognitive test battery was administered at baseline and after 1 and 3 years.

RESULTS

Baseline higher performance in verbal memory (OR = 1.5; 95%CI 1.0, 2.1), visuoconstructive praxis and attention (OR = 1.5; 95%CI 0.9, 2.3), and inhibition (OR = 1.3; 95%CI 0.9, 1.9) were associated with a higher odd of achieving at least 8% weight loss after 3 years follow-up in participants randomized to the intervention group. There were moderate improvements in specific tests of memory and executive functions during follow-up. Higher adherence to the er-MedDiet was associated with greater improvements in memory. Women exhibited lower rates of change in global cognition, PA and QoL. Moreover, improvements in memory correlated with reductions in BMI after 1 year (β_STD = -0.14) and with improvements in PA after 3 years (β_STD = 0.13). Finally, participants who experienced greater improvements in executive functions and global cognition also experienced greater improvements in their QoL.

CONCLUSIONS

This study refines the understanding of the determinants and mutual interrelationships between longitudinally-assessed cognitive performance and weight loss, adding further evidence to the cognitive benefits associated with better adherence to a MedDiet. Our results also suggest that weight loss interventions tailored to the cognitive profile and gender of participants are promising avenues for future studies.

The influence of dietary patterns on outcomes in a Bayesian choice task

BACKGROUND AND AIMS

Previous research has investigated the impact of diet on cognition, but the focus has often been on general cognition. This paper reports on a preregistered cross-sectional study aimed at testing for specific executive function differences across individuals who self-reported one of four distinct dietary patterns: No Diet, No Sugar, Vegetarian, or Mediterranean Diet pattern. Our hypotheses were aimed at testing whether adherence to a specialty diet improved decision making relative to those who reported following No Diet.

METHODS

We administered an incentivized Bayesian choice task to all participants. The task involved multiple components of information-existing information (base rate odds) as well as new information (sample draw evidence)-to allow a test of how these information components were used in making probability assessments, and how this may differ by self-reported dietary pattern. Sample size, hypotheses, and analysis plans were all determined ex ante and registered on the Open Science Framework. Multi-variate linear and non-linear estimation methods were used to analyze the data.

RESULTS

Our data failed to support our pre-registered hypotheses. In fact, we found some evidence that self-reported adherence to a specialty No Sugar Diet was associated with a reduced decision accuracy and was connected to an increased imbalance in how the participant weighted the two available sources of information when making choices.

CONCLUSION

Our results suggest that decision making is nuanced among dietary groups, but that short-term incentivized decisions in an ecologically valid field setting are likely not improved solely by following promoted dietary patterns such as the Mediterranean or Vegetarian diets.

The impact of exercise, sleep, and diet on neurocognitive recovery from mild traumatic brain injury in older adults: A narrative review

Mild traumatic brain injury (mTBI) accounts for a large majority of traumatic brain injuries sustained globally each year. Older adults, who are already susceptible to age-related declines to neurocognitive health, appear to be at an increased risk of both sustaining an mTBI and experiencing slower or impaired recovery. There is also growing evidence that mTBI is a potential risk factor for accelerated cognitive decline and neurodegeneration. Lifestyle-based interventions are gaining prominence as a cost-effective means of maintaining cognition and brain health with age. Consequently, inter-individual variations in exercise, sleep, and dietary patterns could influence the trajectory of post-mTBI neurocognitive recovery, particularly in older adults. This review synthesises the current animal and human literature centred on the mechanisms through which lifestyle-related habits and behaviours could influence acute and longer-term neurocognitive functioning following mTBI. Numerous neuroprotective processes which are impacted by lifestyle factors have been established in animal models of TBI. However, the literature is characterised by a lack of translation to human samples and limited appraisal of the interaction between ageing and brain injury. Further research is needed to better establish the therapeutic utility of applying lifestyle-based modifications to improve post-mTBI neurocognitive outcomes in older adults.

[Perception of loneliness, happiness, and health, and quality of diet. The moderator role of weight status]

Introduction

Aim: to determine the relationship between perceived loneliness, happiness, and health, and quality of diet, observing the moderator role of weight status in elementary school children during the state of alarm decreed for COVID-19. Methods: a descriptive, cross-sectional study in a sample of 116 Spanish schoolchildren. The perception of loneliness, happiness, and health was assessed using three items of the Health Behavior in School-aged Children questionnaire. The quality of their Mediterranean diet was assessed using the Mediterranean Diet Quality Index quetsionnaire for children and adolescents. Anthropometric variables were collected through a self-reported questionnaire, and for the calculation of body mass index the Quetelet index (kg/m2) was used. Results: the descriptive analysis showed no differences in the perception of loneliness, happiness, or health, quality of diet, or anthropometric variables (p > 0.005), except for weight (p < 0.005), according to sex. The inferential analysis showed that higher values in quality of diet are correlated with higher scores in perceived happiness and health (p < 0.005). In turn, the linear regression test showed an association between quality of diet and perception of happiness after the model was adjusted for normal weight (R2 = 0.382; p < 0.005). Likewise, it showed a significant association between quality of diet and perception of health after the model was adjusted for overweight schoolchildren (R2 = 0.455; p < 0.005). Conclusion: the association between perceived health and happiness with quality of diet seems to be moderated by weight status.

Milk, yogurt and cheese intake is positively associated with cognitive executive functions in older adults of the Canadian Longitudinal Study on Aging

BACKGROUND

Dairy products provide essential nutrients such as calcium, vitamins B12 and D, and include bioactive peptides and fermented products, which may be beneficial for cognition, especially in older adults. Yet, few studies of large contemporary cohorts have investigated this relationship using sensitive domain-specific cognitive tests.

METHODS

In community-dwelling older adults of the Canadian Longitudinal Study on Aging (2011-2015), we examined cross-sectional associations between total and specific dairy product intake and performance in three cognitive domains (executive functions, memory, psychomotor speed). Cheese, milk, yogurt, regular-fat, low-fat and fermented dairy product intake frequencies were estimated using a food frequency questionnaire; participants were classified into quartiles. MANCOVA models were applied to estimate differences.

RESULTS

In 7,945 participants (65-86 y, 49% women, 97% Caucasian), the mean dairy product intake was 1.9 (1.1) times/d. Total dairy product, cheese and low-fat dairy product intake were positively associated with the executive function domain and yogurt intake with the memory domain (all p<0.05), independently of important covariates including age, gender, education and diet quality. Intakes of total dairy product, cheese and low-fat dairy were associated with verbal fluency specifically (all p<0.05). Participants with a dairy product intake > 2.5 times/d had a higher score compared to those consuming less. No associations were found with psychomotor speed.

CONCLUSIONS

This large cohort study suggests a specific role for dairy components in executive function phonemic verbal fluency and memory. Dairy product intake, a modifiable factor, may be targeted in cognitive health-promoting interventions.

Nutrition Module design in Maintain Your Brain: an internet-based randomised controlled trial to prevent cognitive decline and dementia

The Maintain Your Brain (MYB) trial is one of the largest internet-delivered multidomain randomised controlled trial designed to target modifiable risk factors for dementia. It comprises four intervention modules: physical activity, nutrition, mental health and cognitive training. This paper explains the MYB Nutrition Module, which is a fully online intervention promoting the adoption of the 'traditional' Mediterranean Diet (MedDiet) pattern for those participants reporting dietary intake that does not indicate adherence to a Mediterranean-type cuisine or those who have chronic diseases/risk factors for dementia known to benefit from this type of diet. Participants who were eligible for the Nutrition Module were assigned to one of the three diet streams: Main, Malnutrition and Alcohol group, according to their medical history and adherence to the MedDiet at baseline. A short dietary questionnaire was administered weekly during the first 10 weeks and then monthly during the 3-year follow-up to monitor whether participants adopted or maintained the MedDiet pattern during the intervention. As the Nutrition Module is a fully online intervention, resources that promoted self-efficacy, self-management and process of change were important elements to be included in the module development. The Nutrition Module is unique in that it is able to individualise the dietary advice according to both the medical and dietary history of each participant; the results from this unique intervention will contribute substantively to the evidence that links the Mediterranean-type diet with cognitive function and the prevention of dementia and will increase our understanding of the benefits of a MedDiet in a Western country.

How can dementia and disability be prevented in older adults: where are we today and where are we going?

Ageing of the population, together with population growth, has brought along an ample increase in the number of older individuals living with dementia and disabilities. Dementia is the main cause of disability in old age, and promoting healthy brain ageing is considered as a key element in diminishing the burden of age-related disabilities. The World Health Organization recently launched the first risk reduction guidelines for cognitive impairment and dementia. According to recent estimates, approximately 40% of dementia cases worldwide could be attributable to 12 modifiable risk factors: low education; midlife hypertension and obesity; diabetes, smoking, excessive alcohol use, physical inactivity, depression, low social contact, hearing loss, traumatic brain injury and air pollution indicating clear prevention potential. Dementia and physical disability are closely linked with shared risk factors and possible shared underlying mechanisms supporting the possibility of integrated preventive interventions. FINGER trial was the first large randomized controlled trial indicating that multidomain lifestyle-based intervention can prevent cognitive and functional decline amongst at-risk older adults from the general population. Within the World-Wide FINGERS network, the multidomain FINGER concept is now tested and adapted worldwide proving evidence and tools for effective and easily implementable preventive strategies. Close collaboration between researchers, policymakers and healthcare practitioners, involvement of older adults and utilization of new technologies to support self-management is needed to facilitate the implementation of the research findings. In this scoping review, we present the current scientific evidence in the field of dementia and disability prevention and discuss future directions in the field.

Adherence to dietary guidelines and cognitive decline from middle age: the Doetinchem Cohort Study

BACKGROUND

Diet, in particular the Mediterranean diet, has been associated with better cognitive function and less cognitive decline in older populations.

OBJECTIVES

To quantify associations of a healthy diet, defined by adherence to either the Mediterranean diet, the WHO guidelines, or Dutch Health Council dietary guidelines, with cognitive function and cognitive decline from middle age into old age.

METHODS

From the Doetinchem Cohort Study, a large population-based longitudinal study, 3644 participants (51% females) aged 45-75 y at baseline, were included. Global cognitive function, memory, processing speed, and cognitive flexibility were assessed at 5-y time intervals up to 20-y follow-up. Adherence to the Mediterranean diet was measured with the modified Mediterranean Diet Score (mMDS), adherence to the WHO dietary guidelines with the Healthy Diet Indicator (HDI), and adherence to the Dutch Health Council dietary guidelines 2015 with the modified Dutch Healthy Diet 2015 index (mDHD15-index). The scores on the dietary indices were classified in tertiles (low, medium, high adherence). Linear mixed models were used to model level and change in cognitive function by adherence to healthy diets.

RESULTS

The highest tertiles of the mMDS, HDI, and mDHD15-index were associated with better cognitive function compared with the lowest tertiles (P values <0.01), for instance at age 65 y equal to being 2 y cognitively younger in global cognition. In addition, compared with the lowest tertiles, the highest tertiles of the mMDS, HDI, and mDHD15-index were statistically significantly associated with 6-7% slower global cognitive decline from age 55 to 75 y, but also slower decline in processing speed (for mMDS: 10%; 95% CI: 2, 18%; for mDHD15: 12%; 95% CI: 6, 21%) and cognitive flexibility (for mDHD15: 10%; 95% CI: 4, 18%).

CONCLUSIONS

Healthier dietary habits, determined by higher adherence to dietary guidelines, are associated with better cognitive function and slower cognitive decline with aging from middle age onwards.