The Mediterranean Diet and 2-Year Change in Cognitive Function by Status of Type 2 Diabetes and Glycemic Control

Dietary Patterns and Brain Health in Middle-Aged and Older Adults: A Narrative Review

Diet has a profound impact on brain health, particularly in middle-aged and older adults, who are at increased risk of cognitive decline and neurodegenerative diseases. Various dietary patterns, including the Mediterranean diet (MedDiet), Dietary Approaches to Stop Hypertension (DASH), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diets, have been linked to improved cognitive function. While the relative effectiveness of these diets on brain health is generally supported by evidence, variability in study results suggests that further research is needed to fully understand their effects across diverse populations. The objective of this descriptive narrative review is to examine the role of dietary patterns in supporting brain health in aging populations and to propose practical dietary strategies for promoting cognitive well-being. A comprehensive review of the existing literature was conducted on PubMed in October 2024, with no restrictions on language, publication date (1966-2024), or geographic location. A total of 18 articles were included in this review, covering the years 2013-2023. Studies assessing the impact of the MedDiet, DASH, MIND, and Western diets on cognitive function in middle-aged and older adults were prioritized. The research findings were synthesized to identify common and unique recommendations across these dietary patterns. The MedDiet consistently showed beneficial effects on cognitive health, including improved memory, processing speed, and long-term protection against neurodegenerative conditions. The DASH and MIND diets demonstrated potential benefits, particularly for specific cognitive domains, but the results were more mixed and inconclusive. In contrast, adherence to a Western diet was associated with negative cognitive outcomes, including cognitive decline and smaller brain volumes. These findings underscore the importance of adopting healthy dietary patterns as a modifiable lifestyle factor to support cognitive aging and inform future public health strategies and clinical guidelines.

Western Mediterranean diet predicts 9-year changes in episodic memory in an adult lifespan sample of Americans

BackgroundThe Mediterranean Diet (MD) is well-studied for slowing cognitive declines. Few studies have examined how a Western MD (wMD) may impact cognitive function.ObjectiveThis study examined whether a wMD predicted less cognitive decline over 9 years in a national sample of American adults. The measures were episodic memory (EM) and executive functioning (EF) at baseline and 9 years follow-up.MethodsThis is a secondary analysis of the Midlife in the United States Study (MIDUS), using a longitudinal cohort design with cross-sectional dietary data. Participants in this study had data from Waves 2 and 3 of MIDUS (n = 833, 46 ± 12 years; 45% male). Regression analyses tested whether wMD adherence predicted 9-year changes in EM and EF. Moderator analyses determined whether the relationship between wMD, EM, and EF differed across sociodemographic characteristics.ResultswMD score at Wave 2 predicted attenuated declines in EM 9 years later (β = 0.06, p = 0.04). The association between wMD and EM was not moderated by age, sex, race, education, or income and thus is consistent across sociodemographic subpopulations. wMD did not predict EF (fully adjusted wMD β = 0.00, p = 0.86). Contextualized effect sizes showed that individuals who strongly adhered to the wMD (+1 SD) experienced ∼50-60% less decline in 9-year EM when compared to those with average adherence.ConclusionsA wMD was related to slowed EM declines across sociodemographic populations in a national U.S. sample. Education is needed about healthful dietary habits, including increased fruit and vegetable intake.

Dietary Quality Analysis Methods for the Type 2 Diabetes Mellitus Population: A Scoping Review

BACKGROUND

High diet quality is associated with improved glycemic control in type 2 diabetes mellitus (T2DM) patients. Thus, mapping the dietary analysis methods that lead to the assessment of diet quality is essential for promoting glycemic control in individuals with T2DM. Therefore, this scoping review aimed to map and synthesize the available evidence on the use of dietary analysis methods to assess diet quality in individuals with T2DM.

METHODS

This review was conducted following the Manual for Evidence Synthesis proposed by the Joanna Briggs Institute and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews Checklist. Articles were searched in the MEDLINE (via PubMed), CINAHL (EBSCO), Embase, LILACS/BVS, Bireme, Scopus, and Web of Science databases. Additionally, grey literature was searched using Google Scholar. The protocol was registered in the Open Science Framework (DOI 10.17605/OSF.IO/HSKU9). Studies that utilized dietary analysis methods to assess diet quality in individuals with T2DM were included.

RESULTS

Overall, 3761 studies were identified, and after the selection process, 33 publications were included for full analysis. Twenty-five indices were mapped to assess diet quality in individuals with T2DM. Only the Diabetes Healthy Eating Index was specific to this population. Considering the application of these methods, most indices were linked to the lowest scores, indicating lower diet quality, poor glycemic control, and other unfavourable health outcomes for the participants.

CONCLUSION

Despite the existence of various dietary methods for analysing diet quality, only one index was specific to individuals with T2DM. It is important to assess the applicability of these methods, considering that the quantity consumed must be evaluated to promote better glycemic control in this population.

Risk Factors, Pathological Changes, and Potential Treatment of Diabetes-Associated Cognitive Dysfunction

BACKGROUND

Diabetes is a prevalent public health issue worldwide, and the cognitive dysfunction and subsequent dementia caused by it seriously affect the quality of life of patients.

METHODS

Recent studies were reviewed to provide a comprehensive summary of the risk factors, pathogenesis, pathological changes and potential drug treatments for diabetes-related cognitive dysfunction (DACD).

RESULTS

Several risk factors contribute to DACD, including hyperglycemia, hypoglycemia, blood sugar fluctuations, hyperinsulinemia, aging, and others. Among them, modifiable risk factors for DACD include blood glucose control, physical activity, diet, smoking, and hypertension management, while non-modifiable risk factors include age, genetic predisposition, sex, and duration of diabetes. At the present, the pathogenesis of DACD mainly includes insulin resistance, neuroinflammation, vascular disorders, oxidative stress, and neurotransmitter disorders.

CONCLUSIONS

In this review, we provide a comprehensive summary of the risk factors, pathogenesis, pathological changes and potential drug treatments for DACD, providing information from multiple perspectives for its prevention and management.

Dietary inflammatory index and brain disorders: a Large Prospective Cohort study

There is emerging evidence that diet plays a key contributor to brain health, however, limited studies focused on the association of dietary inflammatory potential with brain disorders. This study aimed to examine the association of dietary inflammation with brain disorders in the UK biobank. The prospective cohort study used data from 2006 to 2010 from the UK Biobank, with the median follow-up duration for different outcomes ranging between 11.37 to 11.38. Dietary inflammatory index and Energy-adjusted dietary inflammatory index [DII and EDII] were assessed through plausible dietary recalls. Outcomes included brain disorders (all-cause dementia [ACD], Alzheimer's disease [AD], Parkinson's disease [PD], stroke, sleep disorder, anxiety and depression disorder) and brain magnetic resonance imaging measures. Cox proportional-hazard models, restricted cubic spline model [RCS], Ordinary least squares regressions, and structural equation models were used to estimate associations. Of 164,863 participants with available and plausible dietary recalls, 87,761 (53.2%) were female, the mean (SD) age was 58.97 (8.05) years, and the mean (SD) education years was 7.49 (2.97) years. Vegetables and fresh fruits show significant anti-inflammatory properties, while low-fiber bread and animal fats show pro-inflammatory properties. The nonlinear associations of DII and EDII scores with ACD, AD, sleep disorder, stroke, anxiety, and depression were observed. Multivariable-adjusted HRs for participants in highest DII score VS lowest DII score were 1.165 (95% CI 1.038-1.307) for ACD, 1.172 (95% CI 1.064-1.291) for sleep disorder, 1.110 (95% CI 1.029-1.197) for stroke, 1.184 (95% CI 1.111-1.261) for anxiety, and 1.136 (95% CI 1.057-1.221) for depression. Similar results were observed with regard to EDII score. Compared with the lowest EDII score group, the highest group showed a higher risk of anxiety, depression, sleep disorder, stroke and dementia. Results from sensitivity analyses and multivariable analyses were similar to the main results. Pro-inflammatory diets were associated with a higher risk of brain disorders. Our findings suggest a potential means of diet to lower risk of anxiety, depression, sleep disorder, stroke, and dementia.

Probiotics: A potential strategy for improving diabetes mellitus complicated with cognitive impairment

Diabetes mellitus (DM) is a common metabolic disease and one of the diseases with the highest number of complications at present. As the disease progresses, patients will gradually develop diabetes-related cognitive decline, mild cognitive impairment (MCI) or even dementia. The occurrence of diabetes-combined cognitive impairment undoubtedly imposes a heavy burden on patients and their families. Current research suggests that risk factors such as blood glucose levels, insulin resistance, oxidative stress and neuroinflammation have an important role in the development of diabetic cognitive impairment (DCI). With the development of technology and in-depth research, the relationship between the two-way communication between the gut and the brain has been gradually revealed, and more studies have found that the gut microbiota plays an important role in the development of DCI. This review explores the feasibility of probiotics as a potential strategy to assist in the improvement of DCI and its potential mechanisms from the perspective of the factors affecting DCI.

Alzheimer's Disease as Type 3 Diabetes: Understanding the Link and Implications

Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM) are two prevalent conditions that present considerable public health issue in aging populations worldwide. Recent research has proposed a novel conceptualization of AD as "type 3 diabetes", highlighting the critical roles of insulin resistance and impaired glucose metabolism in the pathogenesis of the disease. This article examines the implications of this association, exploring potential new avenues for treatment and preventive strategies for AD. Key evidence linking diabetes to AD emphasizes critical metabolic processes that contribute to neurodegeneration, including inflammation, oxidative stress, and alterations in insulin signaling pathways. By framing AD within this metabolic context, we can enhance our understanding of its etiology, which in turn may influence early diagnosis, treatment plans, and preventive measures. Understanding AD as a manifestation of diabetes opens up the possibility of employing novel therapeutic strategies that incorporate lifestyle modifications and the use of antidiabetic medications to mitigate cognitive decline. This integrated approach has the potential to improve patient outcomes and deepen our comprehension of the intricate relationship between neurodegenerative diseases and metabolic disorders.

Association of level of adherence to Mediterranean diet with cognitive and dementia status in subjects with chronic diseases: a cross-sectional study

BACKGROUND

The Mediterranean diet has been linked to brain neuroprotection. Evidence from meta-analyses showed reduced risk of dementia with greater intake of vegetables and fruits, fish, and the Mediterranean diet. The current study raises important questions about the association between low risk dementia and Mediterranean diet.

OBJECTIVE

The objective was to evaluate the association between levels of adherence to the Mediterranean diet and dementia and cognitive status in subjects 50 years of age and older.

METHOD

The Mediterranean Diet Adherence Screener (MEDAS), the modified 30-item 'Diagnostic and Statistical Manual of Mental Disorders Third Edition (DSM-III) risk of dementia, and the Standard Mini-Mental Status Examination (SMMSE) cognitive status scores were used to assess the levels of adherence to the Mediterranean diet'.

RESULTS

A total of 150 subjects were enrolled in the study. Forty-one (27.3%) had 'suspected or confirmed dementia, while 48 individuals (32%) were categorized as having moderate to severe cognitive decline. Subjects who reported moderate to high adherence to the Mediterranean diet (55, 36.7%) had significantly lower dementia scores (7.0 3.8 versus 17.6 5.1) and higher cognitive (25.4 3.8 versus 8.6 7.2) scores compared to those (38, 25.3%) who reported low adherence to the Mediterranean diet.

CONCLUSION

Subjects who were highly or moderately adherent to the Mediterranean diet had significantly lower dementia scores and better cognitive status than those with low adherence.

Examining individual learning patterns using generalised linear mixed models

Everyone learns differently, but individual performance is often ignored in favour of a group-level analysis. Using data from four different experiments, we show that generalised linear mixed models (GLMMs) and extensions can be used to examine individual learning patterns. Producing ellipsoids and cluster analyses based on predicted random effects, individual learning patterns can be identified, clustered and used for comparisons across various experimental conditions or groups. This analysis can handle a range of datasets including discrete, continuous, censored and non-censored, as well as different experimental conditions, sample sizes and trial numbers. Using this approach, we show that learning a face-named paired associative task produced individuals that can learn quickly, with the performance of some remaining high, but with a drop-off in others, whereas other individuals show poor performance throughout the learning period. We see this more clearly in a virtual navigation spatial learning task (NavWell). Two prominent clusters of learning emerged, one showing individuals who produced a rapid learning and another showing a slow and gradual learning pattern. Using data from another spatial learning task (Sea Hero Quest), we show that individuals' performance generally reflects their age category, but not always. Overall, using this analytical approach may help practitioners in education and medicine to identify those individuals who might need extra help and attention. In addition, identifying learning patterns may enable further investigation of the underlying neural, biological, environmental and other factors associated with these individuals.

SuperAgers and centenarians, dynamics of healthy ageing with cognitive resilience

Graceful healthy ageing and extended longevity is the most desired goal for human race. The process of ageing is inevitable and has a profound impact on the gradual deterioration of our physiology and health since it triggers the onset of many chronic conditions like dementia, osteoporosis, diabetes, arthritis, cancer, and cardiovascular disease. However, some people who lived/live more than 100 years called 'Centenarians" and how do they achieve their extended lifespans are not completely understood. Studying these unknown factors of longevity is important not only to establish a longer human lifespan but also to manage and treat people with shortened lifespans suffering from age-related morbidities. Furthermore, older adults who maintain strong cognitive function are referred to as "SuperAgers" and may be resistant to risk factors linked to cognitive decline. Investigating the mechanisms underlying their cognitive resilience may contribute to the development of therapeutic strategies that support the preservation of cognitive function as people age. The key to a long, physically, and cognitively healthy life has been a mystery to scientists for ages. Developments in the medical sciences helps us to a better understanding of human physiological function and greater access to medical care has led us to an increase in life expectancy. Moreover, inheriting favorable genetic traits and adopting a healthy lifestyle play pivotal roles in promoting longer and healthier lives. Engaging in regular physical activity, maintaining a balanced diet, and avoiding harmful habits such as smoking contribute to overall well-being. The synergy between positive lifestyle choices, access to education, socio-economic factors, environmental determinants and genetic supremacy enhances the potential for a longer and healthier life. Our article aims to examine the factors associated with healthy ageing, particularly focusing on cognitive health in centenarians. We will also be discussing different aspects of ageing including genomic instability, metabolic burden, oxidative stress and inflammation, mitochondrial dysfunction, cellular senescence, immunosenescence, and sarcopenia.

Metabolites and MRI-Derived Markers of AD/ADRD Risk in a Puerto Rican Cohort

Objective

Several studies have examined metabolomic profiles in relation to Alzheimer's disease and related dementia (AD/ADRD) risk; however, few studies have focused on minorities, such as Latinos, or examined Magnetic-Resonance Imaging (MRI)-based outcomes.

Methods

We used multiple linear regression, adjusted for covariates, to examine the association between metabolite concentration and MRI-derived brain age deviation. Metabolites were measured at baseline with untargeted metabolomic profiling (Metabolon, Inc). Brain age deviation (BAD) was calculated at wave 4 (~ 9 years from Boston Puerto Rican Health Study (BPRHS) baseline) as chronologic age, minus MRI-estimated brain age, representing the rate of biological brain aging relative to chronologic age. We also examined if metabolites associated with BAD were similarly associated with hippocampal volume and global cognitive function at wave 4 in the BPRHS.

Results

Several metabolites, including isobutyrylcarnitine, propionylcarnitine, phenylacetylglutamine, phenylacetylcarnitine (acetylated peptides), p-cresol-glucuronide, phenylacetylglutamate, and trimethylamine N-oxide (TMAO) were inversely associated with brain age deviation. Taurocholate sulfate, a bile salt, was marginally associated with better brain aging. Most metabolites with negative associations with brain age deviation scores also were inversely associations with hippocampal volumes and wave 4 cognitive function.

Conclusion

The metabolites identifiedin this study are generally consistent with prior literature and highlight the role of BCAA, TMAO and microbially derived metabolites in cognitive decline.

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.

A novel Mediterranean diet-inspired supplement ameliorates cognitive, microbial, and metabolic deficits in a mouse model of low-grade inflammation

The Mediterranean diet (MD) and its bioactive constituents have been advocated for their neuroprotective properties along with their capacity to affect gut microbiota speciation and metabolism. Mediated through the gut brain axis, this modulation of the microbiota may partly contribute to the neuroprotective properties of the MD. To explore this potential interaction, we evaluated the neuroprotective properties of a novel bioactive blend (Neurosyn240) resembling the Mediterranean diet in a rodent model of chronic low-grade inflammation. Behavioral tests of cognition, brain proteomic analysis, 16S rRNA sequencing, and 1H NMR metabolomic analyses were employed to develop an understanding of the gut-brain axis interactions involved. Recognition memory, as assessed by the novel object recognition task (NOR), decreased in response to LPS insult and was restored with Neurosyn240 supplementation. Although the open field task performance did not reach significance, it correlated with NOR performance indicating an element of anxiety related to this cognitive change. Behavioral changes associated with Neurosyn240 were accompanied by a shift in the microbiota composition which included the restoration of the Firmicutes: Bacteroidota ratio and an increase in Muribaculum, Rikenellaceae Alloprevotella, and most notably Akkermansia which significantly correlated with NOR performance. Akkermansia also correlated with the metabolites 5-aminovalerate, threonine, valine, uridine monophosphate, and adenosine monophosphate, which in turn significantly correlated with NOR performance. The proteomic profile within the brain was dramatically influenced by both interventions, with KEGG analysis highlighting oxidative phosphorylation and neurodegenerative disease-related pathways to be modulated. Intriguingly, a subset of these proteomic changes simultaneously correlated with Akkermansia abundance and predominantly related to oxidative phosphorylation, perhaps alluding to a protective gut-brain axis interaction. Collectively, our results suggest that the bioactive blend Neurosyn240 conferred cognitive and microbiota resilience in response to the deleterious effects of low-grade inflammation.

Metabolites and Cognitive Decline in a Puerto Rican Cohort

Background

Recent studies have identified plasma metabolites associated with cognitive decline and Alzheimer's disease; however, little research on this topic has been conducted in Latinos, especially Puerto Ricans.

Objective

This study aims to add to the growing body of metabolomics research in Latinos to better understand and improve the health of this population.

Methods

We assessed the association between plasma metabolites and global cognition over 12 years of follow-up in 736 participants of the Boston Puerto Rican Health Study (BPRHS). Metabolites were measured with untargeted metabolomic profiling (Metabolon, Inc) at baseline. We used covariable adjusted linear mixed models (LMM) with a metabolite * time interaction term to identify metabolites (of 621 measured) associated with ∼12 years cognitive trajectory.

Results

We observed strong inverse associations between medium-chain fatty acids, caproic acid, and the dicarboxylic acids, azelaic and sebacic acid, and global cognition. N-formylphenylalanine, a tyrosine pathway metabolite, was associated with improvement in cognitive trajectory.

Conclusions

The metabolites identified in this study are generally consistent with prior literature and highlight a role medium chain fatty acid and tyrosine metabolism in cognitive decline.

Flavonols as a Potential Pharmacological Intervention for Alleviating Cognitive Decline in Diabetes: Evidence from Preclinical Studies

Diabetes mellitus is a complex metabolic disease associated with reduced synaptic plasticity, atrophy of the hippocampus, and cognitive decline. Cognitive impairment results from several pathological mechanisms, including increased levels of advanced glycation end products (AGEs) and their receptors, prolonged oxidative stress and impaired activity of endogenous mechanisms of antioxidant defense, neuroinflammation driven by the nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB), decreased expression of brain-derived neurotrophic factor (BDNF), and disturbance of signaling pathways involved in neuronal survival and cognitive functioning. There is increasing evidence that dietary interventions can reduce the risk of various diabetic complications. In this context, flavonols, a highly abundant class of flavonoids in the human diet, are appreciated as a potential pharmacological intervention against cognitive decline in diabetes. In preclinical studies, flavonols have shown neuroprotective, antioxidative, anti-inflammatory, and memory-enhancing properties based on their ability to regulate glucose levels, attenuate oxidative stress and inflammation, promote the expression of neurotrophic factors, and regulate signaling pathways. The present review gives an overview of the molecular mechanisms involved in diabetes-induced cognitive dysfunctions and the results of preclinical studies showing that flavonols have the ability to alleviate cognitive impairment. Although the results from animal studies are promising, clinical and epidemiological studies are still needed to advance our knowledge on the potential of flavonols to improve cognitive decline in diabetic patients.

Adherence to Mediterranean Diet and Depressive Symptomatology Among Boston Area Puerto Ricans

BACKGROUND

Higher Mediterranean diet (MeD) adherence has been linked with lower depressive symptomatology, but research examining this association is limited, especially among Latinos, including mainland U.S. Puerto Ricans. Hence, we examined cross-sectional and longitudinal associations between MeD adherence and self-reported depressive symptomatology in Boston area Puerto Rican adults.

METHODS

The Center for Epidemiologic Studies Depression Scale (CES-D) was used to evaluate depressive symptoms. Adherence to MeD was assessed at all 3 visits. We used multivariable linear regression for baseline cross-sectional analysis, and linear mixed effects modeling over 3 waves of follow-up for longitudinal analysis. We also assessed whether baseline MeD adherence affected 5y CES-D trajectory. We conducted sensitivity analyses among participants without diabetes, and among participants with complete MeD and CES-D measures at all visits.

RESULTS

MeD adherence was significantly associated with CES-D score at baseline (β = -2.0, 95% confidence interval [CI] -4.0, -0.04 for highest vs lowest tertile, p trend = .04) and across 3 waves (β = -1.9, 95% CI = -3.0, -0.8 for highest vs lowest tertile, p trend = .0005). Results were similar in analyses restricted to participants without diabetes, as well as among participants with complete CES-D and MeD scores at all visits.

CONCLUSIONS

While CES-D score was consistently lower in those with higher MeD adherence over 5 years of follow up, no relationship between baseline MeD adherence and 5y CES-D trajectory was observed.

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

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

Mediterranean Diet, Ketogenic Diet or MIND Diet for Aging Populations with Cognitive Decline: A Systematic Review

(1) Background: Compelling evidence shows that dietary patterns can slow the rate of cognitive decline, suggesting diet is a promising preventive measure against dementia. (2) Objective: This systematic review summarizes the evidence of three dietary patterns, the Mediterranean diet, the ketogenic diet and the MIND diet, for the prevention of cognitive decline. (3) Methods: A systematic search was conducted in major electronic databases (PubMed, ScienceDirect and Web of Science) up until 31 January 2022, using the key search terms "Mediterranean diet", "ketogenic diet", "MIND diet", "dementia", "cognition" and "aging". A statistical analysis was performed using RoB 2 and the Jadad scale to assess the risk of bias and methodological quality in randomized controlled trials. (4) Results: Only RCTs were included in this study; there were eleven studies (n = 2609 participants) of the Mediterranean diet, seven studies (n = 313) of the ketogenic diet and one study (n = 37) of the MIND diet. The participants' cognitive statuses were normal in seven studies, ten studies included patients with mild cognitive impairments and two studies included Alzheimer's disease patients. (5) Conclusion: All three dietary interventions have been shown to slow the rate of cognitive decline in the included studies. The Mediterranean diet was shown to be beneficial for global cognition after 10 weeks of adherence, the ketogenic diet had a beneficial effect for patients with diabetes mellitus and improved verbal recognition, while the MIND diet showed benefits in obese patients, improving working memory, verbal recognition, memory and attention.

Design and Implementation of a Culturally-Tailored Randomized Pilot Trial: Puerto Rican Optimized Mediterranean-Like Diet

Background

Adhering to a Mediterranean Diet (MedDiet) is associated with a healthier cardiometabolic profile. However, there are limited studies on the MedDiet benefits for non-Mediterranean racial/ethnic minorities, for whom this diet may be unfamiliar and inaccessible and who have a high risk of chronic diseases.

Objectives

To describe the study design of a pilot trial testing the efficacy of a MedDiet-like tailored to adults in Puerto Rico (PR).

Methods

The Puerto Rican Optimized Mediterranean-like Diet (PROMED) was a single-site 4-mo parallel two-arm randomized pilot trial among a projected 50 free-living adults (25-65 y) living in PR with at least two cardiometabolic risk factors (clinicaltrials.gov registration #NCT03975556). The intervention group received 1 individual nutritional counseling session on a portion-control culturally-tailored MedDiet. Daily text messages reinforced the counseling content for 2 mo, and we supplied legumes and vegetable oils. Participants in the control group received cooking utensils and one standard portion-control nutritional counseling session that was reinforced with daily texts for 2 mo. Text messages for each group were repeated for two more months. Outcome measures were assessed at baseline, 2 and 4 m. The primary outcome was a composite cardiometabolic improvement score; secondary outcomes included individual cardiometabolic factors; dietary intake, behaviors, and satisfaction; psychosocial factors; and the gut microbiome.

Results

PROMED was designed to be culturally appropriate, acceptable, accessible, and feasible for adults in PR. Strengths of the study include applying deep-structure cultural components, easing structural barriers, and representing a real-life setting. Limitations include difficulty with blinding and with monitoring adherence, and reduced timing and sample size. The COVID-19 pandemic influenced implementation, warranting replication.

Conclusions

If PROMED is proven efficacious in improving cardiometabolic health and diet quality, the findings would strengthen the evidence on the healthfulness of a culturally-appropriate MedDiet and support its wider implementation in clinical and population-wide disease-prevention programs.

Adherence to the Dietary Approaches to Stop Hypertension (DASH) Eating Pattern Reduces the Risk of Head and Neck Cancer in American Adults Aged 55 Years and Above: A Prospective Cohort Study

OBJECTIVES

Dietary Approaches to Stop Hypertension (DASH) pattern has been found to aid in the reduction of obesity, oxidative stress, and chronic inflammation, which are all strongly linked to the development of head and neck cancer (HNC). Nevertheless, no epidemiological studies have investigated the association between this dietary pattern and HNC risk. This study was conducted with the purpose of bridging this gap in knowledge.

DESIGN

A prospective cohort study involving 98,459 American adults aged 55 years and older.

SETTING AND PARTICIPANTS

Data were drawn from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Trial. In the present study, participants with dependable energy intake data who furnished baseline and dietary history information were identified as the study population.

METHODS

Diet was assessed by food frequency questionnaires and the DASH score was calculated to assess each participant's adherence to DASH eating pattern. Cox proportional hazards models were used to calculate multivariable adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the occurrence of HNC. To visualize the variation in cancer risk for HNC and its subtypes across the entire spectrum of DASH scores, restricted cubic spline plots were utilized. Additionally, a series of predefined subgroup analyses were performed to identify potential effect modifiers, and several sensitivity analyses were conducted to assess the stability of the findings.

RESULTS

During a follow-up period of 871,879.6 person-years, 268 cases of HNC were identified, comprising 161 cases pertaining to oral cavity and pharynx cancers, as well as 96 cases of larynx cancer. In the fully adjusted model, adherence to the DASH diet was associated with a remarkable 57% reduction in the risk of HNC when comparing extreme quartiles (HR quartile 4 vs 1: 0.43; 95% CI: 0.28, 0.66; P for trend < 0.001). The restricted cubic spline plots demonstrated a linear dose-response relationship between the DASH score and the risk of HNC as well as its subtypes. Subgroup analysis revealed that the protective effect of the DASH diet against HNC was particularly pronounced in individuals with lower daily energy intake. The primary association remained robust in the sensitivity analysis.

CONCLUSIONS

In American middle-aged and older population, adherence to the DASH diet may help prevent HNC, particularly for individuals with lower daily energy intake.

Nutritional intervention for diabetes mellitus with Alzheimer's disease

The combined disease burden of diabetes mellitus (DM) and Alzheimer's disease (AD) is increasing, and the two diseases share some common pathological changes. However, the pharmacotherapeutic approach to this clinical complexity is limited to symptomatic rather than disease-arresting, with the possible exception of metformin. Whether nutritional intervention might extend or synergize with these effects of metformin is of interest. In particular, dietary patterns with an emphasis on dietary diversity shown to affect cognitive function are of growing interest in a range of food cultural settings. This paper presents the association between diabetes and AD. In addition, the cross-cultural nutritional intervention programs with the potential to mitigate both insulin resistance (IR) and hyperglycemia, together with cognitive impairment are also reviewed. Both dietary patterns and nutritional supplementation showed the effects of improving glycemic control and reducing cognitive decline in diabetes associated with AD, but the intervention specificity remained controversial. Multi-nutrient supplements combined with diverse diets may have preventive and therapeutic potential for DM combined with AD, at least as related to the B vitamin group and folate-dependent homocysteine (Hcy). The nutritional intervention has promise in the prevention and management of DM and AD comorbidities, and more clinical studies would be of nutritional scientific merit.

Greater intake of the MEDI diet is associated with better cognitive trajectory in older adults with type 2 diabetes

AIMS

To determine associations of three dietary patterns (Mediterranean (MEDI) diet, the Dietary Approaches to Stop Hypertension (DASH) diet and the Mediterranean- DASH Intervention for Neurodegenerative Delay (MIND) diet) with cognitive decline in older adults with type 2 diabetes mellitus (T2D).

METHODS

This is a longitudinal observational study. Participants (N = 960) from the Israel Diabetes and Cognitive Decline (IDCD) study were included in this study. A multivariable-adjusted model including all three dietary patterns concurrently was developed to investigate their independent effect on cognitive decline.

RESULTS

The mean follow up was 4.1 ± 2.1 years. While high adherence to both the MIND and the MEDI diet was associated with a slower decline, in the multivariable model only the associations of higher MEDI diet intake with greater decline in global cognition and in executive functions remained significant (β = 0.013, SE = 0.006; P = 0.042; β = 0.001, SE = 0.008, Pv = 0.023 respectively).

CONCLUSIONS

In older adults with T2D, adherence to the MEDI is related to better cognitive trajectory. Diet is a meaningful factor in the path linking T2D and cognition.

Association of Mediterranean Diet With Cognitive Decline Among Diverse Hispanic or Latino Adults From the Hispanic Community Health Study/Study of Latinos

IMPORTANCE

The Mediterranean diet may reduce the burden of Alzheimer disease and other associated dementias in Hispanic or Latino people.

OBJECTIVE

To investigate the association of a Mediterranean diet with cognitive performance among community-dwelling Hispanic or Latino adults.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study analyzed data from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) and the Study of Latinos-Investigation of Neurocognitive Aging (SOL-INCA), an HCHS/SOL ancillary study. Cognition tests were administered in the HCHS/SOL from March 2008 to June 2011 (visit 1) and in the SOL-INCA from October 2015 to March 2018 (visit 2). Participants included in the present study had completed a diet assessment at visit 1 and neurocognitive evaluations at visits 1 and 2. Data were analyzed from September 2021 to May 2022.

EXPOSURES

Mediterranean diet adherence was ascertained using the Mediterranean diet score (MDS) and was categorized as low (MDS: 0-4 points), moderate (MDS: 5-6 points), or high (MDS: 7-9 points). The mean of two 24-hour dietary recalls was used to calculate the MDS.

MAIN OUTCOMES AND MEASURES

Cognitive change between visits 1 and 2 was calculated by subtracting the cognitive score at visit 2 from the cognitive score at visit 1 and adjusting by the time elapsed between visits and cognitive score at visit 1. Neurocognitive tests administered were Brief Spanish-English Verbal Learning Test (B-SEVLT) Sum, B-SEVLT Recall, word fluency, and Digit Symbol Substitution Test (DSST). Results of each test were z score-transformed and the means were averaged to create a global cognition score. Complex sample linear regression analysis was used to ascertain the association between MDS and neurocognitive performance at each visit and neurocognitive change.

RESULTS

A total of 6321 participants (mean [SE] age, 56.1 [0.18] years at visit 1; n = 4077 women [57.8%]) were included. Mediterranean diet adherence weighted frequencies were 35.8% (n = 2112 of 6321) for the low adherence group, 45.4% (n = 2795) for the moderate adherence group, and 18.8% (n = 1414) for the high adherence group. In the fully adjusted model, z score-transformed cognitive scores at visit 1 in the high vs low adherence groups were higher for B-SEVLT Sum (β = 0.11; 95% CI, 0.02-0.20), B-SEVLT Recall (β = 0.16; 95% CI, 0.07-0.25), and global cognition (β = 0.10; 95% CI, 0.04-0.16) tests. In the mean follow-up time of 7 years, cognitive change in the high vs low adherence groups was less pronounced for B-SEVLT Sum (β = 0.12; 95% CI, 0.05-0.20) and B-SEVLT Recall (β = 0.14; 95% CI, 0.05-0.23), but not for word fluency, DSST score, or global cognition score.

CONCLUSIONS AND RELEVANCE

Results of this cohort study suggested that high adherence to a Mediterranean diet was associated with better cognitive performance and decreased 7-year learning and memory decline among middle-aged and older Hispanic or Latino adults. Culturally tailored Mediterranean diet may reduce the risk of cognitive decline and Alzheimer disease in this population.

The Effects of Dietary Advanced Glycation End-Products on Neurocognitive and Mental Disorders

Advanced glycation end products (AGEs) are glycated proteins or lipids formed endogenously in the human body or consumed through diet. Ultra-processed foods and some culinary techniques, such as dry cooking methods, represent the main sources and drivers of dietary AGEs. Tissue accumulation of AGEs has been associated with cellular aging and implicated in various age-related diseases, including type-2 diabetes and cardiovascular disease. The current review summarizes the literature examining the associations between AGEs and neurocognitive and mental health disorders. Studies indicate that elevated circulating AGEs are cross-sectionally associated with poorer cognitive function and longitudinally increase the risk of developing dementia. Additionally, preliminary studies show that higher skin AGE accumulation may be associated with mental disorders, particularly depression and schizophrenia. Potential mechanisms underpinning the effects of AGEs include elevated oxidative stress and neuroinflammation, which are both key pathogenetic mechanisms underlying neurodegeneration and mental disorders. Decreasing dietary intake of AGEs may improve neurological and mental disorder outcomes. However, more sophisticated prospective studies and analytical approaches are required to verify directionality and the extent to which AGEs represent a mediator linking unhealthy dietary patterns with cognitive and mental disorders.

Effectiveness of restricted diet with a plate in patients with type 2 diabetes: A randomized controlled trial

BACKGROUND

In view of the complexity of dietary and nutritional education for most patients with type 2 diabetes mellitus (T2DM), a simplified approach called the "restricted diet with a plate" or "plate model" is recommended.

PURPOSE

To evaluate whether the plate model can effectively improve glycemic control and cardiovascular risk markers in type 2 diabetes mellitus (T2DM), while reducing the time devoted to education and avoiding weight gain.

METHODS

The study was a randomized, multicenter, controlled study, conducted between October 2018 and October 2019, among patients with T2DM living in Nanjing. The study included 419 participants who were randomly divided into a plate group and a counting group. The plate model included three components: a low-literacy, color leaflet containing the explanation and composition of the plate model, health education, and medical visits. Patients in the counting group received health education, group medical visits, and a paper booklet containing traditional carbohydrate counting education. Primary outcomes were glycemic control and weight.

RESULTS

Participants in the plate model reduced HbA_1c by 0.7% in the first three months, and reduced to a greater extent at six months (1.44%), but this was not sustained, and HbA_1c increased slightly over the following six months. Fasting plasma glucose (FPG) and 2-h postprandial glucose (2hPG) values were significantly reduced at the endpoint in the plate model (9.25 ± 1.72% vs. 7.44 ± 0.88%, P = 0.008; 12.07 ± 2.94 vs. 8.35 ± 1.99%; P = 0.004); however, the 2hPG values decreased most significantly. Total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels decreased significantly in the plate group, which occurred at six months and lasted for 12 months. In the first three months, the average weight loss in the plate group was 1.2 kg/month (95% CI 0.92-1.48), and in the fourth to twelfth months, the average weight gain was 0.21 kg/month (95% CI 0.08-0.34). There was significant difference in education time between the groups (17.3 ± 4.42 vs. 38.6 ± 12.63; P < 0.001).

CONCLUSIONS

The plate model is at least as effective as the counting model over the short term for glycemic control and perhaps even better for weight and lipid control. Plate model has the potential to improve education of those with low health literacy by reducing reading demands.

Association between Dietary Diversity Changes and Cognitive Impairment among Older People: Findings from a Nationwide Cohort Study

BACKGROUND

Little is known about the role of dietary diversity changes in affecting cognitive function among older people. Therefore, we aimed to evaluate the associations between dietary diversity scores (DDS) changes with cognitive impairment among older adults in a large prospective cohort.

METHODS

Cognitive function was assessed using the Mini-Mental State Examination questionnaire at baseline and follow-up. A total of 9726 participants without Parkinson's disease, dementia, or cognitive impairment were enrolled at baseline. Nine food groups were collected using simplified FFQ at baseline and follow-up surveys. Then nine food groups change patterns and DDS change patterns (overall, plant-based and animal-based) were assessed. The associations of above DDS changes patterns with subsequent cognitive impairment were evaluated. A multivariable-adjusted Cox proportional hazards model was used to estimate HRs and 95%CIs.

RESULTS

We documented 2805 cognitive impairments during 52,325 person-years of follow-up. Compared to high-to-high overall DDS change patterns, the multivariable adjusted HRs (95%CI) for high-to-medium, medium-to-medium, medium-to-low, low-to-medium and low-to-low DDS change patterns were 1.33 (1.12-1.57), 1.11 (0.94-1.32), 1.61 (1.39-1.86), 2.00 (1.66-2.40), 2.30 (1.90-2.78) and 2.80 (2.23-3.53), respectively. Compared with participants with stable DDS change pattern, those who in large improvement of DDS had a 13% lower risk of cognitive impairment (HRs, 0.87; 95%CI: 0.78-0.98). The associations of plant-based DDS, animal-based DDS, or nine food groups DDS change patterns with cognitive impairment were in a similar direction to the main result.

CONCLUSIONS

Protective associations between maintaining high DDS and a reduced risk of cognitive impairment were observed. In contrast, lowering or maintaining a lower DDS increases the risk of cognitive impairment.

Correlation of physical and cognitive impairment in diabetic and hypertensive frail older adults

BACKGROUND

Diabetes and hypertension are common in older adults and represent established risk factors for frailty. Frailty is a multidimensional condition due to reserve loss and susceptibility to stressors with a high risk of death, hospitalizations, functional and cognitive impairment. Comorbidities such as diabetes and hypertension play a key role in increasing the risk of mortality, hospitalization, and disability. Moreover, frail patients with diabetes and hypertension are known to have an increased risk of cognitive and physical impairment. Nevertheless, no study assessed the correlation between physical and cognitive impairment in frail older adults with diabetes and hypertension.

METHODS

We evaluated consecutive frail older patients with diabetes and hypertension who presented at ASL (local health unit of the Italian Ministry of Health) Avellino, Italy, from March 2021 to October 2021. The inclusion criteria were: a previous diagnosis of diabetes and hypertension with no evidence of secondary causes; age > 65 years; a frailty status; Montreal Cognitive Assessment (MoCA) score < 26.

RESULTS

179 patients successfully completed the study. We found a strong and significant correlation between MoCA score and 5-m gait speed test (r: 0.877; p < 0.001). To further verify our results, we performed a linear multivariate analysis adjusting for potential confounding factors, with MoCA score as dependent variable, which confirmed the significant association with glycemia (p < 0.001).

CONCLUSIONS

This is the first study showing a significant correlation between 5-m gait speed test and MoCA score in frail diabetic and hypertensive older adults.

Association Between the EAT-Lancet Diet Pattern and Risk of Type 2 Diabetes: A Prospective Cohort Study

Background:

The EAT-Lancet Commission has promulgated a sustainable dietary guideline and recommended that it was designed to improve the human health and support environmental sustainability.

Objective:

This research was designed to explore the association between this healthy diet pattern (EAT-Lancet diet pattern, EAT-LDP) and risk of type 2 diabetes (T2D).

Methods:

Between 2006 and 2010, a total of 59,849 participants from the UK Biobank without diabetes, cardiovascular disease, or cancers were included at baseline. The EAT-LDP score was constructed on the sum of 14 food components and then categorized into three tertiles. Multivariable Cox proportional hazards regression models were conducted to explore the association between EAT-LDP score and the risk of incident T2D. A mediation analysis was also implemented to disentangle the role of body mass index (BMI) and waist circumference in the relationship between EAT-LDP score and T2D.

Results:

During a median follow-up of 10 years, 2,461 incident T2D cases were recorded. In analyses that compared tertile 3 of the EAT-LDP score (highest) with tertile 1 (lowest), the hazard ratio (HR) for T2D was 0.81 (95% CI: 0.72–0.90) after adjusting for sociodemographic status and health-related factors. Participants who reported a one-point increase in the diet score were associated with a 6% decrease in risk of T2D (HR: 0.94, 95% CI: 0.91–0.97). A significant indirect association was observed between the EAT-LDP score and T2D (β: 0.66, 95% CI: 0.65–0.67), indicating that 44% of the association of EAT-LDP score with T2D was mediated by BMI. Additionally, 40% of the association of EAT-LDP score with T2D was mediated by waist circumference was also observed.

Conclusions:

Our findings indicate that a higher adherence to EAT-LDP contributes to lower risk of T2D. Further independent validation is needed to be conducted before applying the EAT-LDP to inform dietary guidelines.

Breakdown of the blood-brain barrier: A mediator of increased Alzheimer's risk in patients with metabolic disorders?

Metabolic disorders (MDs), including type 1 and 2 diabetes and chronic obesity, are among the faster growing diseases globally and are a primary risk factor for Alzheimer's disease (AD). The term "type-3 diabetes" has been proposed for AD due to the interrelated cellular, metabolic, and immune features shared by diabetes, insulin resistance (IR), and the cognitive impairment and neurodegeneration found in AD. Patients with MDs and/or AD commonly exhibit altered glucose homeostasis and IR; systemic chronic inflammation encompassing all of the periphery, blood-brain barrier (BBB), and central nervous system; pathological vascular remodeling; and increased BBB permeability that allows transfusion of neurotoxic molecules from the blood to the brain. This review summarizes the components of the BBB, mechanisms through which MDs alter BBB permeability via immune and metabolic pathways, the contribution of BBB dysfunction to the manifestation and progression of AD, and current avenues of therapeutic research that address BBB permeability. In addition, issues with the translational applicability of current animal models of AD regarding BBB dysfunction and proposals for future directions of research that address the relationship between MDs, BBB dysfunction, and AD are discussed.

Diagnosis of TCM symptoms and analysis of risk factors of mild cognitive impairment in patients with type 2 diabetes mellitus

OBJECTIVE

To explore the diagnosis of traditional Chinese medicine (TCM) syndrome and analyze the risk factors of mild cognitive impairment (MCI) in patients with type 2 diabetes mellitus (T2DM).

METHODS

141 T2DM patients, who were hospitalized in department of endocrinology of our hospital from February 2020 to December 2020, were chosen as research subjects. The patients were divided into an observation group (n=65, T2DM with MCI) and a control group (n=76, T2DM with normal cognitive function) according to the Montreal Cognitive Assessment (MoCA) score and diagnostic criteria of MCI. Pearson correlation analysis was used to study the correlation between MoCA score and influencing factors, and multiple logistic regression analyses were applied to analyze the risk factors of T2DM patients.

RESULTS

Deficiency of kidney essence (34/65, 52.31%) and phlegm obstructing orifices (16/65, 2.62%) were common in T2DM patients with MCI. The observation group had apparently lower MoCA scores than the control group (23.46±3.12 points vs. 27.39±2.56 points, t=8.2150, P=0.0000). According to the results of multivariate logistic regression analysis, age, course of diabetes, homocysteine (HCY) and glycosylated hemoglobin (HbAlc) were the independent risk factors of MCI, and the education level was a protective factor.

CONCLUSION

Mental deficiency and phlegm obstruction are common in T2DM patients complicated with MCI. The factors such as age, diabetes course, education degree, HCY and HbAlc are closely related to MCI. The occurrence of MCI in T2DM patients can be prevented by improving the education degree of patients, effective control of blood glucose and reduction of HCY level.

Metformin Use and Cognitive Function in Older Adults With Type 2 Diabetes Following a Mediterranean Diet Intervention

Background and Purpose: Both adherence to the Mediterranean diet (MedDiet) and the use of metformin could benefit the cognitive performance of individuals with type 2 diabetes, but evidence is still controversial. We examined the association between metformin use and cognition in older adults with type 2 diabetes following a MedDiet intervention. Methods: Prospective cohort study framed in the PREDIMED-Plus-Cognition sub-study. The PREDIMED-Plus clinical trial aims to compare the cardiovascular effect of two MedDiet interventions, with and without energy restriction, in individuals with overweight/obesity and metabolic syndrome. The present sub-study included 487 cognitively normal subjects (50.5% women, mean ± SD age of 65.2 ± 4.7 years), 30.4% of them (N = 148) with type 2 diabetes. A comprehensive battery of neurocognitive tests was administered at baseline and after 1 and 3 years. Individuals with type 2 diabetes that exhibited a good glycemic control trajectory, either using or not using metformin, were compared to one another and to individuals without diabetes using mixed-effects models with inverse probability of treatment weights. Results: Most subjects with type 2 diabetes (83.1%) presented a good and stable glycemic control trajectory. Before engaging in the MedDiet intervention, subjects using metformin scored higher in executive functions (Cohen's d = 0.51), memory (Cohen's d = 0.38) and global cognition (Cohen's d = 0.48) than those not using metformin. However, these differences were not sustained during the 3 years of follow-up, as individuals not using metformin experienced greater improvements in memory (β = 0.38 vs. β = 0.10, P = 0.036), executive functions (β = 0.36 vs. β = 0.02, P = 0.005) and global cognition (β = 0.29 vs. β = -0.02, P = 0.001) that combined with a higher MedDiet adherence (12.6 vs. 11.5 points, P = 0.031). Finally, subjects without diabetes presented greater improvements in memory than subjects with diabetes irrespective of their exposure to metformin (β = 0.55 vs. β = 0.10, P < 0.001). However, subjects with diabetes not using metformin, compared to subjects without diabetes, presented greater improvements in executive functions (β = 0.33 vs. β = 0.08, P = 0.032) and displayed a higher MedDiet adherence (12.6 points vs. 11.6 points, P = 0.046). Conclusions: Although both metformin and MedDiet interventions are good candidates for future cognitive decline preventive studies, a higher adherence to the MedDiet could even outweigh the potential neuroprotective effects of metformin in subjects with diabetes.

MIND Diet and Cognitive Function over Eight Years in Puerto Rican Older Adults

BACKGROUND

Healthy diets have been associated with better cognitive function. Socio-economic factors including education, poverty and job complexity may modify the relationship between diet and cognition.

METHODS

We used adjusted linear mixed models to examine the association between long-term adherence to the Mediterranean-Dietary Approaches to Stop Hypertension - Intervention for Neurodegenerative Delay (MIND) diet and cognitive function over 8 years of follow-up in Puerto Rican adults residing in the Boston, MA area (aged 45 to 75 years at baseline). We also examined whether the MIND diet - cognition association was confounded or modified by socioeconomic measures.

RESULTS

In both cross-sectional and longitudinal analyses the highest, vs lowest, MIND quintile was associated with better cognition function (ß = 0.093; 95% CI: 0.035, 0.152; P trend = 0.0019), but not with cognitive trajectory over 8 years. Education <=8 th grade (ß = -0.339; 95% CI: 0.394, -0.286; P < 0.0001) and income-to-poverty ratio <120% (ß = -0.049; 95% CI: -0.092, -0.007; P = 0.024) were significantly associated with lower cognitive function, while higher job complexity (ß = 0.008; 95% CI: 0.006, 0.011; P < 0.0001) was associated with better cognition function. These variables acted confounders, but not effect modifiers of the MIND-diet - cognitive function relationship.

CONCLUSION

Adherence to the MIND diet was associated with better cognitive function at baseline and over 8 years of follow-up, however MIND diet was not associated with 8-year cognitive trajectory. More studies are needed to better understand whether the MIND diet is protective against long-term cognitive decline.

Prospective Study of Plant-Based Dietary Patterns and Diabetes in Puerto Rican Adults

BACKGROUND

Vegetarian-type dietary patterns have been associated with reducing the risk of developing diabetes and may function as an effective strategy for diabetes management.

OBJECTIVES

We aimed to examine the associations between adherence to plant-based diet indices and the risk of developing diabetes in the Boston Puerto Rican Health Study.

METHODS

Puerto Rican adults (n = 646), aged 45-75 y and free of diabetes at baseline, were included. Dietary intake was assessed via a validated FFQ. Three plant-based dietary indices were calculated: an overall plant-based diet index (PDI), a healthful plant-based diet index (hPDI), and an unhealthful plant-based diet index (uPDI). Incident diabetes was defined as fasting plasma glucose ≥ 126 mg/dL (7.0 mmol/L), glycated hemoglobin ≥ 6.5% (48 mmol/mol), or use of hypoglycemic agents during follow-up. Cox proportional hazards were used to evaluate associations between the dietary patterns and incidence of diabetes, adjusting for potential confounders, such as age, sex, socioeconomic status, lifestyle factors, obesity, total energy intake, depressive symptomatology, and plasma concentrations of lipids.

RESULTS

During a mean of 4.2 y of follow-up, we identified 134 diabetes cases. After adjustment for covariates, higher hPDI was associated with lower risk of developing diabetes (adjusted HR for the highest compared with the lowest tertile: 0.54; 95% CI: 0.31, 0.94; P-trend = 0.03). In contrast, the PDI and uPDI were not significantly associated with the risk of diabetes (P-trend > 0.3 for both).

CONCLUSIONS

The healthful plant-based dietary index, but not the total plant-based dietary index, was inversely associated with diabetes risk. These findings suggest that the quality of plant-based diets must be considered when recommending plant-based diets for the prevention of diabetes.This trial was registered at clinicaltrials.gov as NCT01231958.

Dietary patterns in middle age: effects on concurrent neurocognition and risk of age-related cognitive decline

Context

Diet plays a critical role in cognitive integrity and decline in older adults. However, little is known about the relationship between diet and cognitive integrity in middle age.

Objective

To investigate the relationship between dietary patterns in healthy middle-aged adults and neurocognition both in middle age and later in life.

Data Sources

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, the following electronic databases were searched: Web of Science, Scopus, PubMed, and PsychInfo.

Data Extraction

Data from eligible articles was extracted by 2 reviewers.

Data Analysis

Articles included in the systematic review were synthesized (based on the synthesis without meta-analysis reporting guidelines) and assessed for quality (using the Joanna Briggs Institute checklist for randomized controlled trials, cohort studies, and cross-sectional studies) by 2 reviewers.

Results

Of 1558 studies identified, 34 met the eligibility criteria for inclusion. These comprised 9 cross-sectional studies, 23 longitudinal or prospective cohort studies, and 2 randomized controlled trials. Findings were mixed, with some studies reporting a significant positive relationship between adherence to various “healthy” dietary patterns and neurocognition, but others reporting no such relationship.

Conclusion

This systematic review demonstrated that adherence to the Mediterranean diet and other healthy dietary patterns in middle age can protect neurocognition later in life.

Systematic Review Registration

PROSPERO registration no. CRD42020153179.

Mediterranean diet in type 2 diabetes: An updated overview of pharmacological activities of cardiometabolic and reproductive outcomes

Mediterranean diet represents an optimal "way of living" to pursue in order to preserve health and well-being. A large body of evidence indicates that the Mediterranean diet is effective in preventing diabetes and improving both glycemic control and cardiometabolic health in people with type 2 diabetes. Moreover, in the recent years a growing interest risen on the importance of dietary style choice in both male and female sexual and reproductive health. This review aims at providing an updated overview of the latest available evidence on the effects of Mediterranean diet on cardiovascular, metabolic, and reproductive health in the context of type 2 diabetes.

Circulating Plasma Metabolites and Cognitive Function in a Puerto Rican Cohort

BACKGROUND

Minorities, including mainland Puerto Ricans, are impacted disproportionally by Alzheimer's disease (AD), dementia, and cognitive decline. Studying blood metabolomics in this population has the potential to probe the biological underpinnings of this health disparity.

OBJECTIVE

We performed a comprehensive analysis of circulating plasma metabolites in relation to cognitive function in 736 participants from the Boston Puerto Rican Health Study (BPRHS) who underwent untargeted mass-spectrometry based metabolomics analysis and had undergone a battery of in-person cognitive testing at baseline.

METHODS

After relevant exclusions, 621 metabolites were examined. We used multivariable regression, adjusted for age, sex, education, apolipoprotein E genotype, smoking, and Mediterranean dietary pattern, to identify metabolites related to global cognitive function in our cohort. LASSO machine learning was used in a complementary analysis to identify metabolites that could discriminate good from poor extremes of cognition. We also conducted sensitivity analyses: restricted to participants without diabetes, and to participants with good adherence to Mediterranean diet.

RESULTS

Of 621 metabolites, FDR corrected (p < 0.05) multivariable linear regression identified 3 metabolites positively, and 10 negatively, associated with cognitive function in the BPRHS. In a combination of FDR-corrected linear regression, logistic regression regularized via LASSO, and sensitivity analyses restricted to participants without diabetes, and with good adherence to the Mediterranean diet, β-cryptoxanthin plasma concentration was consistently associated with better cognitive function and N-acetylisoleucine and tyramine O-sulfate concentrations were consistently associated with worse cognitive function.

CONCLUSION

This untargeted metabolomics study identified potential biomarkers for cognitive function in a cohort of Puerto Rican older adults.

MIND diet and cognitive performance in older adults: a systematic review

Cognitive decline is a rapidly increasing public health concern. A healthy diet has potential in preserving brain and maintaining cognitive health. This systematic review was designed to evaluate the relationship between Mediterranean-DASH diet intervention for neurodegenerative delay (MIND) diet and cognitive functioning in older adults. PubMed, SCOPUS, Embase, Cochrane Library, and Google Scholar databases were searched to extract original studies on humans published until July 2020, without date restrictions. Articles that evaluated the association between MIND diet and cognitive performance in older adults were included. Duplicated and irrelevant studies were screened out and data were obtained through critical analysis. Quality of the articles and risk of bias was assessed by Newcastle-Ottawa and Cochrane Collaboration's quality assessment tools. Of the 135 studies retrieved, 13 articles (9 cohort, 3 cross-sectional, and 1 RCT studies) were included in the final review. All of the included studies indicated that adherence to the MIND diet was positively associated with specific domains, but not all, of cognition and global cognitive function (78% of the studies) in older adults. MIND diet was superior to other plant-rich diets including Mediterranean, Dietary Approaches to Stop Hypertension, Pro-Vegetarian and Baltic Sea diets, for improving cognition. Adherence to the MIND diet may possibly be associated with an improved cognitive function in older adults. MIND diet may be superior to other plant-rich diets for improving cognition.

Effects of daily almond consumption for six months on cognitive measures in healthy middle-aged to older adults: a randomized control trial

BACKGROUND

Age-related cognitive decline is a major public health issue. Almonds are rich in nutrients that benefit cognitive function.

OBJECTIVE

To investigate the impact of almonds on cognition in elderly adults.

DESIGN

In a six-month, single-blinded, randomized-controlled trial, the effects of an almond intervention on cognition in healthy, middle-aged/older adults (50-75 years) was tested. Subjects were assigned to one of three groups: 1.5 oz/d almond (n = 19), 3 oz/d almond (n = 24), or 3.5 oz/d snack (control, matched for macronutrients in 3.0 oz almonds, (n = 17). Serum analyses for tocopherols, oxidative status and inflammation, and cognition were assessed at baseline (M0), three (M3), and six (M6) months.

RESULTS

At M6, serum alpha-tocopherol concentrations increased by 8% from M0 (p < 0.05) in the 3 oz almond group but did not increase in the other groups. Serum markers of inflammation and oxidative stress were not significantly different throughout the study among the groups. There was no difference in change over time in cognitive tests among the groups. However, there was a significant improvement in visuospatial working memory (p = 0.023), visual memory and learning (p = 0.017), and spatial planning and working memory (p < 0.001) in subjects receiving 3 oz/d almonds at M6, while the snack group showed no improvement.

CONCLUSIONS

Almonds did not significantly improve cognitive function in cognitively intact middle-aged/older adults over six months. However, a significant improvement at M6 in cognitive measures was observed with 3 oz/d almonds. While these results are encouraging, a study of longer duration in subjects at risk for age-related cognitive decline is warranted.Trial registration: ClinicalTrials.gov identifier: NCT03093896.

Folate, vitamin B-12, and cognitive function in the Boston Puerto Rican Health Study

BACKGROUND

There is evidence that low plasma vitamin B-12 and folate individually, as well as an imbalance of high folic acid and low vitamin B-12 status, may be associated with lower cognitive function.

OBJECTIVES

We examined dietary and plasma folate and vitamin B-12 status, and their interaction, in relation to cognitive function in a cohort of older Puerto Rican adults.

METHODS

The design is cross-sectional, with 1408 participants from the Boston Puerto Rican Health Study (mean ± SD age: 57.1 ± 7.9 y). Cognitive function was assessed with a comprehensive test battery and a global composite score was derived. Plasma folate, vitamin B-12, and methylmalonic acid (MMA) were assessed in fasting blood samples.

RESULTS

After adjusting for covariates, high plasma folate and high plasma vitamin B-12 were each positively associated with global cognitive score (β: 0.063; 95% CI: -0.0008, 0.127; P = 0.053 and β: 0.062; 95% CI: 0.009, 0.12; P = 0.023, respectively, for logged values, and β: 0.002; 95% CI: 0.00005, 0.004; P-trend = 0.044 and β: 0.00018; 95% CI: 0.00001, 0.0003; P-trend = 0.036, respectively, across tertiles). Nine percent of participants had vitamin B-12 deficiency (plasma vitamin B-12 < 148 pmol/L or MMA > 271 nmol/L), but none were folate deficient (plasma folate < 4.53 nmol/L). Deficient compared with higher vitamin B-12 was significantly associated with lower cognitive score (β: -0.119; 95% CI: -0.208, -0.029; P = 0.009). We could not examine the interaction for vitamin B-12 deficiency and high plasma folate, because there were too few individuals (<1% of the cohort) in this category to draw conclusions.

CONCLUSIONS

Low plasma vitamin B-12 and low plasma folate were each associated with worse cognitive function in this population. Vitamin B-12 deficiency was prevalent and clearly associated with poorer cognitive function. More attention should be given to identification and treatment of vitamin B-12 deficiency in this population. Additional, larger studies are needed to examine the effect of vitamin B-12 deficiency in the presence of high exposure to folic acid.

Nutrition Management in Older Adults with Diabetes: A Review on the Importance of Shifting Prevention Strategies from Metabolic Syndrome to Frailty

The increasing prevalence of older adults with diabetes has become a major social burden. Diabetes, frailty, and cognitive dysfunction are closely related to the mechanisms of aging. Insulin resistance, arteriosclerosis, chronic inflammation, oxidative stress, and mitochondrial dysfunction may be common mechanisms shared by frailty and cognitive impairment. Hyperglycemia, hypoglycemia, obesity, vascular factors, physical inactivity, and malnutrition are important risk factors for cognitive impairment and frailty in older adults with diabetes. The impact of nutrients on health outcomes varies with age; thus, shifting diet therapy strategies from the treatment of obesity/metabolic syndrome to frailty prevention may be necessary in patients with diabetes who are over 75 years of age, have frailty or sarcopenia, and experience malnutrition. For the prevention of frailty, optimal energy intake, sufficient protein and vitamin intake, and healthy dietary patterns should be recommended. The treatment of diabetes after middle age should include the awareness of proper glycemic control aimed at extending healthy life expectancy with proper nutrition, exercise, and social connectivity. Nutritional therapy in combination with exercise, optimal glycemic and metabolic control, and social participation/support for frailty prevention can extend healthy life expectancy and maintain quality of life in older adults with diabetes mellitus.

Alternate Healthy Eating Index is Positively Associated with Cognitive Function Among Middle-Aged and Older Hispanics/Latinos in the HCHS/SOL

BACKGROUND

Diet quality may be an important area of focus for promoting cognitive health; however, the association between diet quality and cognitive function among Hispanics/Latinos remains largely unexamined. We hypothesized that a healthier diet quality will be associated with better cognitive function in middle-aged and older Hispanics/Latinos.

OBJECTIVE

The objective of this study was to examine associations between the Alternate Healthy Eating Index (AHEI-2010), a measure of diet quality, and cognitive function in middle-aged and older Hispanics/Latinos.

METHODS

Data from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) Visit 1 (2008-2011) were used (n = 8461; ages 45-74 y). Cognitive function was assessed with tests of verbal learning and memory, verbal fluency, and processing speed; a global cognition score was derived by summing the z scores of individual tests. Dietary intake was assessed via two 24-h recalls. Total AHEI-2010 score was categorized into quintiles (higher quintiles indicating healthier diet). Linear regression models were used to examine associations between AHEI-2010 quintiles and cognitive function adjusting for sociodemographic characteristics, daily energy intake, type 2 diabetes, smoking, and depressive symptoms.

RESULTS

Compared with the lowest quintile, in the second to fourth AHEI-2010 quintiles, global cognition scores were significantly higher by 0.28, 0.52, and 0.48 units (P-trend = 0.042). In the second to fifth AHEI-2010 quintiles, verbal learning scores were significantly higher by 0.60, 0.62, 0.92, and 0.88 units, and verbal memory scores were higher by 0.33, 0.40, 0.52, and 0.46 units (P-trend = 0.020 and 0.007, respectively). No associations were observed between the AHEI-2010 and verbal fluency or processing speed (P-trend = 0.49 and 0.84, respectively). Among AHEI-2010 components, adequate consumption of vegetables, alcohol, and whole fruits were each associated with better cognitive function.

CONCLUSIONS

An overall healthier diet quality was associated with better global cognition, verbal learning, and verbal memory in middle-aged and older Hispanics/Latinos.

Influence of the Mediterranean and Ketogenic Diets on Cognitive Status and Decline: A Narrative Review

Alzheimer's disease (AD) is the most common form of senile dementia, accounting for up to 70% of dementia cases. AD is a slowly progressive disease, which causes global mental deterioration by affecting various cognitive areas. A growing body of evidence has demonstrated that lifestyle habits and nutritional patterns could delay the natural course of the neurodegeneration process. There is no single dietary pattern unequivocally proven to prevent AD. Nevertheless, epidemiological data suggest that by adopting several dietary habits, especially if accompanied with a healthy lifestyle, the negative consequences of AD could potentially be delayed. Alongside with others, two specific eating patterns have been well investigated concerning their potential beneficial effect on cognitive status: the Mediterranean diet (MedDi) and the Ketogenic Diet (KD). Despite the different underlying mechanisms, both of them have demonstrated a fairly profitable role in reducing or delaying cognitive impairment. The aim of the present narrative review is to overview the existing research on the efficacy of MedDi and KD against AD-related cognitive decline, focusing on the proposed protective mechanisms of action. Although the current knowledge on this complex topic does not allow us, at this point, to make exhaustive conclusions, this information could be of help in order to better characterize the possible role of MedDi and KD as nonpharmacological therapies in the treatment of AD and, more generically, of neurodegenerative disorders.

Associations between cognitive performance and Mediterranean dietary pattern in patients with type 1 or type 2 diabetes mellitus

Diabetes mellitus has been associated with impaired cognitive performance, particularly in verbal memory. Mediterranean diets (MedD) may lead to improvements in overall and single cognitive functions. We hypothesised that adherence to MedD associates with better performance in verbal memory in patients with type 1 or type 2 diabetes. Thus, we performed a cross-sectional analysis including patients with recently diagnosed type 1 (n = 75) or type 2 diabetes (n = 118), metabolically healthy individuals (n = 41) and individuals with type 1 (n = 44) or type 2 diabetes (n = 62) of at least five years after diagnosis. Participants underwent comprehensive metabolic phenotyping and cognitive testing. Adherence to the Modified Mediterranean diet scale (MMDS) was computed from a food frequency questionnaire. Among patients with type 2 diabetes with a known diabetes duration ≥5 years, closer adherence to the MMDS was associated with higher score in verbal memory after adjustment for potential confounders (P = 0.043). Adherence to the MMDS did not relate to verbal memory in recently diagnosed type 2 diabetes (P = 0.275), recently diagnosed or longer-standing type 1 diabetes (P = 0.215 and P = 0.626, respectively) or metabolically healthy individuals (P = 0.666). In conclusion, closer adherence to MedD may exert beneficial effects on cognitive performance in the course of type 2 diabetes.