Monounsaturated, trans, and saturated Fatty acids and cognitive decline in women

Association between the geriatric nutritional risk index and cognitive functions in older adults: a cross-sectional study from National Health and Nutrition Examination Survey

Objective

To investigate the associations between the geriatric nutritional risk index (GNRI) with cognitive functions among U.S. older adults. (Patients were classified into two nutrition risk groups based on the GNRI).

Methods

Our analysis utilized data from the cross-sectional National Health and Nutrition Examination Survey (NHANES) conducted between 2011 and 2014. Cognitive function was measured using CERAD test, AFT and DSST. Composite z-scores were obtained by summing test-specific z-scores of the above three cognitive tests and were used to assess the global cognitive function. We employed weighted logistic regression models to evaluate the associations between GNRI and nutritional status (low and high GNRI) with cognitive function among older participants. The non-linear relationship was described using fitted smoothed curves and threshold effect analyses. Subgroup analysis and interaction tests were also conducted.

Results

This study included 2,592 older participants aged 60 years and older. After adjusting for confounding variables, the GNRI was positively associated with AFT (β = 0.05, 95% CI 0.005-0.096, p-value = 0.0285), DSST (β = 0.192, 95% CI 0.078-0.305, p-value = 0.0010) and the composite z-scores (β = 0.027, 95% CI 0.010-0.044, p-value = 0.0024). The results also showed that the high-GNRI group was significantly associated with AFT (β = 0.922, 95% CI 0.166-1.677, p-value = 0.0169), DSST (β = 2.791, 95% CI 0.884-4.698, p-value = 0.0042) and composite z-scores (β = 0.405, 95% CI 0.115-0.695, p-value = 0.0062) likewise had significant positive correlations, using the low-GNRI group as a reference. In addition, inflection points with CERAD and composite z-scores were found at GNRI of 108.016, and 105.371, respectively. Specifically, on the left side of the inflection point GNRI levels were positively correlated with CERAD and composite z-scores (CERAD β = 0.087, 95% CI 0.024-0.150, p-value = 0.0070; composite z-scores β = 0.065, 95% CI 0.040-0.091, p-value <0.0001), while on the right side of the inflection point were significantly negatively associated (CERAD β = -0.295, 95% CI -0.529 to -0.062, p-value = 0.0133, composite z-scores β = -0.050, 95% CI -0.091 to -0.008, p-value = 0.0184).

Conclusion

Lower GNRI was associated with poorer performance in several cognitive domains. Additionally, there was a non-linear positive association between GNRI and cognitive function in normal nutritional states, for excessive GNRI may cause cognitive decline.

Effects of saturated and monounsaturated fatty acids on cognitive impairment: evidence from Mendelian randomization study

BACKGROUND

Prior observational studies have suggested correlations between saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) with cognitive function. However, causal relationships remains unclear.

METHODS

We assessed the causal impact of two SFAs (palmitic acid [PA] and stearic acid [SA]) and two MUFAs (oleic acid [OA] and palmitoleic acid [POA]) on cognitive function-related traits, and dementia-related traits by univariable Mendelian randomization (UVMR) and multivariable Mendelian randomization (MVMR) analyses.

RESULTS

UVMR indicated β of 0.060 (P = 4.05E-06) for cognitive performance score and 0.066 (P = 4.21E-04) for fluid intelligence per standard deviation (SD) increase in OA level. MVMR indicated: (i) β of -0.608 (P = 8.37E-05) for fluid intelligence score per SD increase in POA; (ii) β of 0.074 (P = 0.018) for fluid intelligence score per SD increase in OA; (iii) β of 0.029 (P = 0.033) for number of incorrect matches in round per SD increase in PA; and (iv) β of 0.039 (P = 0.032) for number of incorrect matches in round per SD increase in SA. In addition, a secondary MVMR analysis after excluding the effect of polyunsaturated fatty acids suggested that: (i) β of -0.043 (P = 1.97E-02) for cognitive performance score per SD increase in PA and (ii) β of -0.079 (P = 1.79E-03) for cognitive performance score per SD increase in SA.

CONCLUSIONS

Overall, UVMR and MVMR suggest that OA may be beneficial for cognitive function, while POA, PA, and SA may have detrimental effects on cognitive function.

Explainable AI and transformer models: Unraveling the nutritional influences on Alzheimer's disease mortality

This pioneering study introduces the use of transformer-based machine learning models and explainable AI approaches to explore the impact of nutrition on Alzheimer's disease (AD) mortality. Using data from the Third National Health and Nutrition Examination Survey (Nhanes iii 1988 to 1994) and the NHANES III Mortality-Linked File (2019) databases, we investigate the intricate relationship between various nutritional factors and AD mortality. Our approach features a novel application of transformer models, which are then benchmarked against established methods like random forests and support vector machines. This comparison not only underscores the strengths of transformer models in handling complex medical datasets but also highlights their potential for providing deeper insights into disease progression. Key findings, such as the significant roles of Platelet distribution width in AD mortality in transformer and Serum Vitamin B12 in random forest, are enhanced by the use of Explainable Artificial Intelligence (XAI), particularly the Shapley Additive Explanations (SHAP) and the integrated gradient methods. This study serves as a vital step forward in applying advanced AI techniques to medical research, offering new perspectives in understanding and combating Alzheimer's Disease.

Risk factors of cognitive impairment: Impact of decline in oral function

Cognitive impairment and subsequent dementia are the major causes of disability and need for nursing care among older people in worldwide. The purpose is to review well-known risk factors for cognitive impairment and dementia, focusing on the relationship between decline in oral function and current prevention strategies. Various non-modifiable and modifiable risk factors are related to cognitive impairment. Effects of oral function to cognitive impairment is not yet well recognized in the medical community, although masticatory function, occlusal force, and number of teeth have been reported to be related to cognitive function. Furthermore, occlusal force rather than number of teeth was significantly related to the early stages of cognitive impairment, and that a decline in occlusal force seemed to lead to cognitive impairment directly and indirectly through dietary intake. This relationship was significant only for occlusal force, which may be associated with the early stages of cognitive decline. Nutritional change caused by reduced masticatory function is suggested as a possible explanation. Therefore, rehabilitation or maintenance of oral function should be sought to prevent cognitive impairment.

Red Blood Cell Fatty Acid Profiles Are Significantly Altered in South Australian Mild Cognitive Impairment and Alzheimer's Disease Cases Compared to Matched Controls

Nutritional imbalances have been associated with a higher risk for cognitive impairment. This study determined the red blood cell (RBC) fatty acid profile of newly diagnosed mild cognitive impairment (MCI) and Alzheimer's disease (AD) patients compared to age and gender-matched controls. There was a significant increase in palmitic acid (p < 0.00001) for both MCI and AD groups. Saturated fatty acids were significantly elevated in the MCI group, including stearic acid (p = 0.0001), arachidic acid (p = 0.003), behenic acid (p = 0.0002), tricosanoic acid (p = 0.007) and lignoceric acid (p = 0.001). n-6 polyunsaturated fatty acids (PUFAs) were significantly reduced in MCI, including linoleic acid (p = 0.001), γ-linolenic acid (p = 0.03), eicosatrienoic acid (p = 0.009) and arachidonic acid (p < 0.00004). The n-3 PUFAs, α-linolenic acid and docosahexaenoic acid, were both significantly reduced in MCI and AD (p = 0.0005 and p = 0.00003). A positive correlation was evident between the Mini-Mental State Examination score and nervonic acid in MCI (r = 0.54, p = 0.01) and a negative correlation with γ-linolenic acid in AD (r = -0.43, p = 0.05). Differences in fatty acid profiles may prove useful as potential biomarkers reflecting increased risk for dementia.

Dietary Fats and Cognitive Status in Italian Middle-Old Adults

The increase in life expectancy led to a significant rise in the prevalence of age-related neurological diseases, such as cognitive impairment, dementia, and Alzheimer’s disease. Although genetics certainly play a role, nutrition emerged as a key factor in maintaining optimal cognitive function among older adults. Therefore, the study aimed to investigate whether specific categories and subcategories of dietary fats, based on carbon-chain length, are associated with cognitive status in a cohort of 883 Italian participants over the age of 50. Methods: The intake of total, single class of dietary fat, such as saturated fatty acids (SFA), monounsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA), and also single fatty acids grouped according to carbon-chain length, were evaluated by food frequency questionnaires (FFQs). Cognitive health was assessed using the short portable mental status questionnaire (SPMSQ). Results: After adjustment for potential confounding factors subjects with a moderate consumption of both short-chain SFA (for Q2 vs. Q1, OR = 0.23, 95% CI: 0.08, 0.66) and middle-chain SFA specifically lauric acid (C12:0) intake (for Q2 vs. Q1, OR = 0.27, 95% CI: 0.09, 0.77) were less likely to suffer from cognitive impairment. Among single MUFAs, erucic acid (C22:1) intake resulted in an inverse association, in a linear way, with cognitive impairment (for Q4 vs. Q1, OR = 0.04, 95% CI: 0.00, 0.39). Conversely, moderate intake of linoleic acid (C18:2) was associated with cognitive impairment (Q3 vs. Q1, OR = 4.59, 95% CI: 1.51, 13.94). Regarding other PUFAs, individuals consuming moderate intake alpha linolenic acid (C18:3) were less likely to have cognitive impairment (for Q3 vs. Q1, OR = 0.19, 95% CI: 0.06, 0.64). Conclusions: Total SFA intake appeared to be inversely associated with cognitive impairment. Regarding specific subtypes of fatty acids, the results mostly referred to short- and middle-chain SFA. Further studies are needed to validate the results of the present study.

Diet quality indices and changes in cognition during chemotherapy

PURPOSE

No evidence-based prevention strategies currently exist for cancer-related cognitive decline (CRCD). Although patients are often advised to engage in healthy lifestyle activities (e.g., nutritious diet), little is known about the impact of diet on preventing CRCD. This secondary analysis evaluated the association of pre-treatment diet quality indices on change in self-reported cognition during chemotherapy.

METHODS

Study participants (n = 96) completed the Block Brief Food Frequency Questionnaire (FFQ) before receiving their first infusion and the PROMIS cognitive function and cognitive abilities questionnaires before infusion and again 5 days later (i.e., when symptoms were expected to be their worst). Diet quality indices included the Dietary Approaches to Stop Hypertension (DASH), Alternate Mediterranean Diet (aMED), and a low carbohydrate diet index and their components. Descriptive statistics were generated for demographic and clinical variables and diet indices. Residualized change models were computed to examine whether diet was associated with change in cognitive function and cognitive abilities, controlling for age, sex, cancer type, treatment type, depression, and fatigue.

RESULTS

Study participants had a mean age of 59 ± 10.8 years and 69% were female. Although total diet index scores did not predict change in cognitive function or cognitive abilities, higher pre-treatment ratio of aMED monounsaturated/saturated fat was associated with less decline in cognitive function and cognitive abilities at 5-day post-infusion (P ≤ .001).

CONCLUSIONS

Higher pre-treatment ratio of monounsaturated/saturated fat intake was associated with less CRCD early in chemotherapy. Results suggest greater monounsaturated fat and less saturated fat intake could be protective against CRCD during chemotherapy.

Sex Differences in Cognition Across Aging

Sex and gender differences are seen in cognitive disturbances in a variety of neurological and psychiatry diseases. Men are more likely to have cognitive symptoms in schizophrenia whereas women are more likely to have more severe cognitive symptoms with major depressive disorder and Alzheimer's disease. Thus, it is important to understand sex and gender differences in underlying cognitive abilities with and without disease. Sex differences are noted in performance across various cognitive domains - with males typically outperforming females in spatial tasks and females typically outperforming males in verbal tasks. Furthermore, there are striking sex differences in brain networks that are activated during cognitive tasks and in learning strategies. Although rarely studied, there are also sex differences in the trajectory of cognitive aging. It is important to pay attention to these sex differences as they inform researchers of potential differences in resilience to age-related cognitive decline and underlying mechanisms for both healthy and pathological cognitive aging, depending on sex. We review literature on the progressive neurodegenerative disorder, Alzheimer's disease, as an example of pathological cognitive aging in which human females show greater lifetime risk, neuropathology, and cognitive impairment, compared to human males. Not surprisingly, the relationships between sex and cognition, cognitive aging, and Alzheimer's disease are nuanced and multifaceted. As such, this chapter will end with a discussion of lifestyle factors, like education and diet, as modifiable factors that can alter cognitive aging by sex. Understanding how cognition changes across age and contributing factors, like sex differences, will be essential to improving care for older adults.

Association Between Adherence to the MIND Diet and Cognitive Performance is Affected by Income: The ELSA-Brasil Study

BACKGROUND

The relationship between the Mediterranean-DASH Diet Intervention for Neurodegenerative Delay (MIND) diet and cognition has not been widely investigated in low- to middle-income countries. We investigated the relationship between MIND diet and cognition in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) baseline data.

METHODS

We included 11,788 participants. MIND diet adherence was based on the intake of 15 components according to a food frequency questionnaire. We analyzed the association between MIND diet adherence and global cognition, memory, and executive function using adjusted linear regression. We examined the interaction between income and MIND diet adherence on cognition and presented income stratified analyses.

RESULTS

MIND diet adherence was not associated with cognition in the whole sample. Income was an effect modifier of MIND adherence on global cognition (P=0.03) and executive function (P<0.001). For participants with high income, greater adherence was associated with better executive function [β=0.015, 95% confidence interval (CI)=0.002; 0.028, P=0.025]; while for participants with low income, greater adherence was associated with lower global cognition (β=-0.020, 95% CI=-0.036; -0.005, P=0.010) and executive function (β=-0.023, 95% CI=-0.039; -0.007, P=0.004). Adherence to the MIND diet was higher among participants with high income (P<0.001).

CONCLUSION

For high-income participants, greater adherence was associated with better cognitive performance; for low-income participants, greater adherence was associated with lower cognitive performance.

Association of adherence to the Australian Dietary Guidelines with cognitive performance and cognitive decline in the Sydney Memory and Ageing Study: a longitudinal analysis

This study investigated associations of adherence to the Australian Dietary Guidelines (ADG) with cognitive performance and cognitive decline over 6 years. We used longitudinal data from the Sydney Memory and Aging Study comprising 1037 community-dwelling non-demented participants aged 70–90 years. Dietary intake was assessed at baseline using the Dietary Questionnaire for Epidemiological Studies Version 2. Adherence to the ADG was scored using the Dietary Guideline Index 2013 (DGI-2013). Cognition was assessed using neuropsychological tests in six cognitive domains and global cognition at baseline and 2, 4 and 6 years later. Linear mixed models analysed the association between adherence to the ADG and cognitive function and cognitive decline over 6 years. Results indicated that overall adherence to the ADG was suboptimal (DGI-2013 mean score 43⋅8 with a standard deviation of 10⋅1; median score 44, range 12–73 with an interquartile range of 7). The percent of participants attaining recommended serves for the five food groups were 30⋅2 % for fruits, 11⋅2 % for vegetables, 54⋅6 % for cereals, 28⋅9 % for meat and alternatives and 2⋅1 % for dairy consumption. Adherence to the ADG was not associated with overall global cognition over 6 years (β = 0⋅000; 95 % CI: −0⋅007, 0⋅007; P = 0⋅95). Neither were DGI-2013 scores associated with change in global cognitive performance over 6 years (β = 0⋅002; 95 % CI: −0⋅002, 0⋅005; P = 0⋅41) nor in any individual cognitive domains. In conclusion, adherence to the ADG was not associated with cognitive health over time in this longitudinal analysis of older Australians. Future research is needed to provide evidence to support specific dietary guidelines for neurocognitive health among Australian older adults.

US Older Adults That Consume Avocado or Guacamole Have Better Cognition Than Non-consumers: National Health and Nutrition Examination Survey 2011-2014

Purpose: The goal of this study is to examine how avocado relates to cognitive function among older adults. Methods: A total of 2,886 National Health and Nutrition Examination Survey 2011-2014 participants aged 60 or older met the eligibility criteria and were included of our cross-sectional study. Participants were binarily classified as avocado consumers (i.e., reported consuming any avocado/guacamole in either 24-h dietary recalls) or non-consumers. Cognitive performance was evaluated with: Consortium to Establish a Registry for Alzheimer's disease (CERAD)-immediate and delayed recall (IWR/DWR), the Animal Fluency test, and the Digit Symbol Substitution Test. We calculated the education-dependent z-scores for each subject because education level can impact cognitive function. Global cognitive score, an average of the z-scores for each cognitive test, was calculated in participants who had completed all four tests. To account for relevant covariates, we tested for mean differences in cognition between consumers and non-consumers using independent sample t-tests and ANCOVA, special cases of ordinary least squares regression. Results: Avocado consumers had significantly better cognitive scores across all cognitive tests and the global cognition score (p < 0.05) in the unadjusted model. Some mean differences attenuated after adjusting for potential confounders, but others remained significant. Compared to non-consumers, avocado consumers had significantly higher z-scores of 0.15, 0.15, and 0.11 for CERAD IWR and DWR, and global cognition score, respectively (all p < 0.05 in adjusted models). Conclusion: Avocado consumption was associated with significantly better IWR, DWR, and the overall global cognition score, which remained significant when controlling for all relevant confounders.

Prevalence of Dementia among Well-Educated Old-Age Pensioners in Parakou (Benin) in 2014

INTRODUCTION

The number of people living with dementia is growing worldwide and most rapidly in low- and middle-income countries. Little is known about dementia in Benin. We estimated the prevalence of dementia among retired people in Parakou, a northern city in Benin, and then assessed associated factors.

METHODS

A cross-sectional study was performed in Parakou from July to August 2014. Participants were recruited at 2 centers, the National Center of Social Security and the Public Treasury of Benin. Participants with cognitive impairment were defined as having a low cognitive score (<7) for the brief version of the Community Screening Interview for Dementia and were invited to neurological examination. DSM-IV-TR criteria were used to diagnose dementia and the HACHINSKI score was used to differentiate dementia subtypes. A logistic regression model was performed to identify factors associated with dementia.

RESULTS

Overall, 440 retired people were included in the study. They were mainly male (92.3%) and their mean age was 64.9 ± 6.0 years. The prevalence of cognitive impairment was 7.7% (95% CI 5.2-10.2). Fourteen participants were diagnosed with dementia, representing a prevalence of 3.2% (95% CI 1.5-4.8). Alzheimer disease was the most frequent subtype (64.3%), followed by vascular dementia (21.4%). Retired people diagnosed with dementia were all men and were aged between 61 and 71 years. Most of them were living alone. The main factors associated with dementia were older age, low fruit and vegetables consumption, and living alone.

DISCUSSION

This study showed a low prevalence of dementia among retired older people in Benin. Despite this, greater attention must be given to the potential burden dementia places on families for better care, before the expected aging of the population becomes more significant.

APOE4 genotype exacerbates the impact of menopause on cognition and synaptic plasticity in APOE-TR mice

The impact of sex and menopausal status in Alzheimer's disease remains understudied despite increasing evidence of greater female risk, particularly in APOE4 carriers. Utilizing female APOE-TR mice maintained on a high-fat diet background we induced ovarian failure through repeated VCD injections, to mimic human menopause. At 12 months of age, recognition memory and spatial memory were assessed using object recognition, Y-maze spontaneous alternation, and Barnes maze. A VCD*genotype interaction reduced the recognition memory (P < .05), with APOE4 VCD-treated animals unable to distinguish between novel and familiar objects. APOE4 mice displayed an additional 37% and 12% reduction in Barnes (P < .01) and Y-maze (P < .01) performance, indicative of genotype-specific spatial memory impairment. Molecular analysis indicated both VCD and genotype-related deficits in synaptic plasticity with BDNF, Akt, mTOR, and ERK signaling compromised. Subsequent reductions in the transcription factors Creb1 and Atf4 were also evident. Furthermore, the VCD*genotype interaction specifically diminished Ephb2 expression, while Fos, and Cnr1 expression reduced as a consequence of APOE4 genotype. Brain DHA levels were 13% lower in VCD-treated animals independent of genotype. Consistent with this, we detected alterations in the expression of the DHA transporters Acsl6 and Fatp4. Our results indicate that the combination of ovarian failure and APOE4 leads to an exacerbation of cognitive and neurological deficits.

Consumption of dietary nuts in midlife and risk of cognitive impairment in late-life: the Singapore Chinese Health Study

BACKGROUND

evidence from prospective studies investigating the association between consumption of nuts in midlife and risk of cognitive impairment in late life is limited.

METHODS

this study analysed data from 16,737 participants in a population-based cohort, the Singapore Chinese Health Study. Intake of nuts was assessed using a validated food-frequency questionnaire at baseline (1993-1998), when participants were 45-74 years old (mean age = 53.5 years). Cognitive function was tested using the Singapore modified Mini-Mental State Examination during the third follow-up visit (2014-2016), when participants were 61-96 years old (mean age = 73.2 years). Cognitive impairment was defined using education-specific cut-off points. Logistic regression models were used to estimate the odds ratio (OR) and the 95% confidence interval (CI) for the association between intake and risk of cognitive impairment.

RESULTS

cognitive impairment was identified in 2,397 (14.3%) participants. Compared with those who consumed <1 serving/month of nuts, participants who consumed 1-3 servings/month, 1 serving/week and ≥2 servings/week had 12% (95% CI 2-20%), 19% (95% CI 4-31%) and 21% (2-36%) lower risk of cognitive impairment, respectively (P-trend = 0.01). Further adjustment for intake of unsaturated fatty acids attenuated the association to non-significance. Mediation analysis showed that the 50.8% of the association between nuts and risk of cognitive impairment was mediated by the intake of total unsaturated fatty acids (P < 0.001).

CONCLUSION

higher intake of nuts in midlife was related to a lower risk of cognitive impairment in late life, which was partly mediated by unsaturated fatty acids.

Effects of very low-carbohydrate vs. high-carbohydrate weight loss diets on psychological health in adults with obesity and type 2 diabetes: a 2-year randomized controlled trial

AIMS

Very low-carbohydrate (LC) diets are popular for type 2 diabetes (T2DM) management; however, long-term effects on psychological health remain largely unknown. This study reports the effects of a LC diet on mood and cognitive function after 2 years and explores the potential predictors of changes in psychological health.

METHODS

115 adults (57% males; age: 58.5 ± 7.1 years) with obesity and T2DM were randomized to consume an energy reduced (~ 500 to 1000 kcal/day deficit), LC diet [14% energy as carbohydrate, 28% protein, 58% fat (< 10% saturated fat)] or an isocaloric high unrefined carbohydrate, low-fat diet [HC: 53% carbohydrate, 17% protein, 30% fat (< 10% saturated fat)] for 2 years. Both diets were combined with aerobic/resistance exercise (1 h, 3 days/week). Mood/well-being [Beck Depression Inventory (BDI), Spielberger State Anxiety Inventory (SAI), Profile of Mood States (POMS)], diabetes-related quality of life [Diabetes-39 (D-39)] and distress [Problem Areas in Diabetes (PAID) Questionnaire], and cognitive function were assessed during and post-intervention.

RESULTS

61 (LC: 33, HC: 28) participants completed the study. Weight loss was 9.1% after 12 months and 6.7% after 2 years with no difference between diet groups. There were no differences between the groups for the changes in any psychological health outcome (smallest p ≥ 0.19 for all time x diet interactions). Overtime, improvements in BDI, POMS [Total Mood Disturbance (TMD); four subscales], PAID, and D-39 (three subscales) scores occurred (p ≤ 0.05, time). Stepwise regression analysis showed improvements in BDI, POMS (TMD; two subscales), D-39, SAI, and PAID scores were significantly (p < 0.05) correlated with reductions in body weight and glycated hemoglobin.

CONCLUSION

In adults with obesity and T2DM, energy-restricted LC and HC diets produced comparable long-term improvements on a comprehensive range of psychological health outcomes. The findings suggest both diets can be used as a diabetes management strategy as part of a holistic lifestyle modification program without concern of negative effects on mental well-being or cognition.

TRIAL REGISTRATION

ACTRN12612000369820, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=362168&isReview=true . Data described in the manuscript, code book, and analytic code will not be made available because approval has not been granted by participants.

The impact of dietary macronutrient intake on cognitive function and the brain

Macronutrients - carbohydrates, fats, and proteins - supply the nutrients required for optimal functioning. Inadequate intake compromises both physical and brain health. We synthesized research on macronutrients from whole meals on cognitive function in healthy adults and identified underlying mechanisms. Intake of simple carbohydrates ('sugars') is consistently associated with decreased global cognition whereas consumption of complex carbohydrates correlates with successful brain aging and improved memory both in the short- and long-term. Saturated fatty acid intake correlates with decreased memory and learning scores whereas omega-3 intake correlates positively with memory scores. Protein intake boosts executive function and working memory when task-demands are high. Individual differences affecting the macronutrient-cognition relationship are age, physical activity, and glucose metabolism. Neural correlates reflect findings on cognitive functions: cortical thickness and cerebral amyloid burden correlate with sugar intake, inflammatory status and cerebral glucose metabolism correlate with fatty acid intake. Key mechanisms by which dietary macronutrients affect the brain and cognition include glucose and insulin metabolism, neurotransmitter actions, and cerebral oxidation and inflammation. In conclusion, macronutrient intake affects cognitive function both acutely and in the long-term, involving peripheral and central mechanisms. A healthy diet supports brain integrity and functionality, whereas inadequate nutrition compromises it. Studying diet can be key to nutritional recommendations, thereby improving the landscape of mental health and healthy brain aging.

Association of Major Dietary Protein Sources With All-Cause and Cause-Specific Mortality: Prospective Cohort Study

Background

Dietary recommendations regarding protein intake have been focused on the amount of protein. However, such recommendations without considering specific protein sources may be simplistic and insufficient.

Methods and Results

We included 102 521 postmenopausal women enrolled in the Women’s Health Initiative between 1993 and 1998, and followed them through February 2017. During 1 876 205 person‐years of follow‐up, 25 976 deaths occurred. Comparing the highest with the lowest quintile, plant protein intake was inversely associated with all‐cause mortality (hazard ratio [HR], 0.91 [0.86, 0.96]), cardiovascular disease mortality (HR, 0.88 [0.79, 0.97]), and dementia mortality (HR, 0.79 [0.67, 0.94]). Among major protein sources, comparing the highest with the lowest quintile of consumption, processed red meat (HR, 1.06 [1.01, 1.10]) or eggs (HR, 1.14 [1.10, 1.19]) was associated with higher risk of all‐cause mortality. Unprocessed red meat (HR, 1.12 [1.02, 1.23]), eggs (HR, 1.24 [1.14, 1.34]), or dairy products (HR, 1.11 [1.02, 1.22]) was associated with higher risk of cardiovascular disease mortality. Egg consumption was associated with higher risk of cancer mortality (HR, 1.10 [1.02, 1.19]). Processed red meat consumption was associated with higher risk of dementia mortality (HR, 1.20 [1.05, 1.32]), while consumption of poultry (HR, 0.85 [0.75, 0.97]) or eggs (HR, 0.86 [0.75, 0.98]) was associated with lower risk of dementia mortality. In substitution analysis, substituting of animal protein with plant protein was associated with a lower risk of all‐cause mortality, cardiovascular disease mortality, and dementia mortality, and substitution of total red meat, eggs, or dairy products with nuts was associated with a lower risk of all‐cause mortality.

Conclusions

Different dietary protein sources have varying associations with all‐cause mortality, cardiovascular disease mortality, and dementia mortality. Our findings support the need for consideration of protein sources in future dietary guidelines.

The Role of Hypothalamic Inflammation in Diet-Induced Obesity and Its Association with Cognitive and Mood Disorders

Obesity is often associated with cognitive and mood disorders. Recent evidence suggests that obesity may cause hypothalamic inflammation. Our aim was to investigate the hypothesis that there is a causal link between obesity-induced hypothalamic inflammation and cognitive and mood disorders. Inflammation may influence hypothalamic inter-connections with regions important for cognition and mood, while it may cause dysregulation of the Hypothalamic-Pituitary-Adrenal (HPA) axis and influence monoaminergic systems. Exercise, healthy diet, and glucagon-like peptide receptor agonists, which can reduce hypothalamic inflammation in obese models, could improve the deleterious effects on cognition and mood.

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.

Dietary Fatty Acid Factors in Alzheimer's Disease: A Review

Alzheimer's disease (AD) is an irreversible neurodegenerative disease characterized by brain function disorder and chronic cognitive function impairment. The onset of AD is complex and is mostly attributed to interactions between genetic factors and environmental factors. Lifestyle, dietary habits, and food consumption are likely to play indispensable functions in aged-related neurodegenerative diseases in elderly people. An increasing number of epidemiological studies have linked dietary fatty acid factors to AD, raising the point of view that fatty acid metabolism plays an important role in AD initiation and progression as well as in other central nervous system disorders. In this paper, we review the effects of the consumption of various dietary fatty acids on AD onset and progression and discuss the detrimental and beneficial effects of some typical fatty acids derived from dietary patterns on the pathology of AD. We outline these recent advances, and we recommend that healthy dietary lifestyles may contribute to preventing the occurrence and decreasing the pathology of AD.

Plasma fatty acid profile is related to cognitive function in obese Chinese populations (35-64 years): A cross-sectional study

BACKGROUND

A fast-growing body of evidence suggests that dietary lipids influence cognition, but the effects of dietary fatty acid (FA) intake and plasma FA profile on cognitive function in obese populations are currently unclear. The present study aimed to investigate the dietary FA intakes and plasma FA composition and their association with cognitive functions in obese and overweight populations aged 35-64 years.

METHODS

A total of 672 subjects were recruited and divided into normal-weight, overweight, and obese groups based on their body mass index (BMI). Dietary information was collected using a semiquantified food frequency questionnaire. Plasma FAs composition was examined using gas chromatography. The mini-mental state examination and Montreal Cognitive Assessment scales were carried out to assess the cognitive performance of each participant. Dietary FA intake and plasma FA composition were compared with rank transformation followed by one-way ANOVA analysis across different BMI groups. Spearman rank correlation analysis was used to investigate the correlation between dietary FA intake and plasma FA composition and cognitive functions in normal-weight, overweight, and obese subjects, respectively.

RESULTS

Overweight and obese subjects consumed larger amounts of saturated fatty acids (SFAs) compared to normal-weight participants (p < .05). Obese populations also had higher plasma levels of total SFAs and total monounsaturated fatty acid (MUFAs) than normal-weight subjects (both p < .05). In addition, plasma levels of SFAs, polyunsaturated fatty acids (PUFAs), and MUFAs were negatively correlated with cognitive functions in obese subjects but showed no correlation in normal-weight and overweight subjects.

CONCLUSIONS

From current data, we found higher plasma levels of SFA, PUFA, and MUFA in obese populations, which were associated with declined cognition. Lowering plasma FA levels may help maintaining normal cognitive functions in obese people.

Effect of a 12-Week Almond-Enriched Diet on Biomarkers of Cognitive Performance, Mood, and Cardiometabolic Health in Older Overweight Adults

Long term nut consumption is associated with reduced risk of coronary heart disease and better cognitive function. This study examined supplementing habitual diets with almonds or carbohydrate-rich snack foods (providing 15% energy) on biomarkers of cardiovascular and metabolic health, mood and cognitive performance. Participants (overweight/obese, 50-80 years) were randomised to an almond-enriched diet (AED) or isocaloric nut-free diet (NFD) for 12 weeks. Body weight, blood lipids, glucose, insulin, blood pressure (BP), arterial stiffness, cell adhesions molecules, C reactive protein (CRP), mood, and cognitive performance (working memory primary outcome), dietary profiles and energy intake/expenditure were measured at baseline and Week 12 in 128 participants (n = 63 AED, n = 65 NFD). Compared with NFD, AED was associated with altered macro and micronutrient profiles, but no differences in energy intake or expenditure. The AED significantly reduced triglycerides and SBP but there were no other changes in cardiometabolic biomarkers, mood, or cognitive performance. The inclusion of almonds in the diet improves aspects of cardiometabolic health without affecting cognitive performance or mood in overweight/obese adults.

Midlife Dietary Intakes of Monounsaturated Acids, n-6 Polyunsaturated Acids, and Plant-Based Fat Are Inversely Associated with Risk of Cognitive Impairment in Older Singapore Chinese Adults

BACKGROUND

Previous studies have shown inconsistent results for the relation between dietary fat intake and cognitive function in the elderly. Furthermore, prospective studies on this topic among the Chinese population are scarce.

OBJECTIVES

We aimed to examine the association between midlife dietary fat intake and risk of cognitive impairment in the elderly.

METHODS

Prospective cohort analysis was conducted among 16,736 participants from the Singapore Chinese Health Study. Dietary information was assessed by a validated FFQ at baseline (1993-1998) when participants aged 45-74 y (mean: 53.5; SD: 6.22). Cognitive impairment was identified using the Singapore modified Mini-Mental State Examination at the third follow-up visit (2014-2016) when participants aged 61-96 y (mean: 73.2; SD: 6.41). Multivariable logistic regression models were used to calculate ORs and 95% CIs.

RESULTS

Cognitive impairment was presented in 2397 participants. When substituted for total carbohydrate, dietary fat intake was inversely related to cognitive impairment (OR comparing extreme quartiles: 0.80; 95% CI: 0.67, 0.94; P-trend = 0.003). The OR (95% CI) comparing extreme quartiles of specific dietary fats was 1.08 (0.89, 1.31; P-trend = 0.51) for SFAs, 0.80 (0.64, 0.99; P-trend = 0.02) for MUFAs, 0.84 (0.72, 0.99; P-trend = 0.02) for PUFAs, 0.92 (0.77, 1.09; P-trend = 0.49) for n-3 PUFAs, and 0.83 (0.70, 0.98; P-trend = 0.01) for n-6 PUFAs. An inverse association was found for plant-based fat (OR: 0.84; 95% CI: 0.72, 0.98; P-trend = 0.02), but not for animal-based fat (OR: 0.96; 95% CI: 0.81, 1.15; P-trend = 0.76). When substituted for SFAs, the OR (95% CI) was 0.77 (0.61, 0.97; P-trend = 0.02) for MUFAs and 0.82 (0.70, 0.95; P-trend = 0.003) for PUFAs.

CONCLUSIONS

We found that substitution of total carbohydrate or SFAs with MUFAs and PUFAs, particularly n-6 PUFAs, was related to a lower risk of cognitive impairment in elderly Chinese participants. In addition, an inverse association with cognitive impairment was found for plant-based fat.

Three consecutive weeks of nutritional ketosis has no effect on cognitive function, sleep, and mood compared with a high-carbohydrate, low-fat diet in healthy individuals: a randomized, crossover, controlled trial

BACKGROUND

The high-fat ketogenic diet (KD) has become an increasingly popular diet not only in overweight/obese populations, or those with clinical conditions, but also in healthy non-overweight populations.

OBJECTIVE

Because there are concerns about the association between high-fat diets and cognitive decline, this study aimed to determine the effects of a KD compared with an isocaloric high-carbohydrate, low-fat (HCLF) diet on cognitive function, sleep, and mood in healthy, normal-weight individuals.

METHODS

Eleven healthy, normal-weight participants (mean age: 30 ± 9 y) completed this randomized, controlled, crossover study. Participants followed 2 isocaloric diets-an HCLF diet (55% carbohydrate, 20% fat, and 25% protein) and a KD (15% carbohydrate, 60% fat, and 25% protein)-in a randomized order for a minimum of 3 wk, with a 1-wk washout period between diets. Measures of β-hydroxybutyrate confirmed that all participants were in a state of nutritional ketosis during post-KD assessments (baseline: 0.2 ± 0.2 mmol/L; KD: 1.0 ± 0.5 mmol/L; washout: 0.2 ± 0.1 mmol/L; and HCLF: 0.3 ± 0.2 mmol/L). Cognitive function was assessed using a validated, psychological computer-based test battery before and after each diet. Subjective measures of mood and sleep were also monitored throughout the study using validated scales.

RESULTS

Three weeks of sustained nutritional ketosis, compared with the HCLF diet, had no effect on speed and accuracy responses in tasks designed to measure vigilance (speed: P = 0.39, Cohen's d = 0.26; accuracy: P = 0.99, Cohen's d = 0.04), visual learning and memory (speed: P = 0.99, Cohen's d = 0.04; accuracy: P = 0.99, Cohen's d = 0.03), working memory (speed: P = 0.62, Cohen's d = 0.26; accuracy: P = 0.98, Cohen's d = 0.07), and executive function (speed: P = 0.60, Cohen's d = 0.31; accuracy: P = 0.90, Cohen's d = 0.19). Likewise, mood, sleep quality, and morning vigilance did not differ (P > 0.05) between the dietary interventions.

CONCLUSION

The results of our randomized, crossover, controlled study suggest that 3 wk of sustained nutritional ketosis had no effect on cognitive performance, mood, or subjective sleep quality in a sample of healthy individuals. This trial was registered in the Pan African Clinical Trial Registry as PACTR201707002406306.

Association of Diet Quality and Vegetable Variety with the Risk of Cognitive Decline in Chinese Older Adults

Diet quality plays an important role in dementia prevention. It remains unclear how the joint effect of vegetable variety and diet quality affects cognition. This study aimed to explore the association of diet quality and vegetable variety with cognitive decline in older adults. This prospective cohort study (2011–2015) included 436 community-dwelling elders in Taipei. Diet quality, assessed by the modified Alternative Healthy Eating Index (mAHEI), was computed from a food frequency questionnaire at baseline (2011–2013). Vegetable variety indicated the number of different vegetable groups, adjusted for vegetable quantity. Multivariable linear and logistic regression models were used to explore the association of diet quality and vegetable variety with the decline of global and domain-specific cognition over two years. Our findings suggest that high diet quality (the highest tertile of mAHEI) was associated with a lower risk of both global cognitive decline (adjusted odds ratio (AOR) = 0.54, confidence interval (CI) = 0.31–0.95) and decline of attention domain (AOR = 0.56, CI = 0.32–0.99) compared with low diet quality. In elders with high vegetable variety, high diet quality was associated with a lower risk of global cognitive decline (AOR = 0.49, CI = 0.26–0.95). We therefore concluded that high diet quality along with diverse vegetable intake was associated with a lower risk of cognitive decline in older adults.

Dietary Long-Chain Fatty Acids and Cognitive Performance in Older Australian Adults

Convincing evidence exists for the positive effect of an improvement in diet quality on age-related cognitive decline, in part due to dietary fatty acid intake. A cross-sectional analysis of data from the Hunter Community Study (HCS) (n = 2750) was conducted comparing dietary data from a validated Food Frequency Questionnaire (FFQ) with validated cognitive performance measures, Audio Recorded Cognitive Screen (ARCS) and Mini Mental State Examination (MMSE). Adjusted linear regression analysis found statistically significant associations between dietary intake of total n-6 fatty acids (FA), but no other FAs, and better cognitive performance as measured by the ARCS (RC = 0.0043; p = 0.0004; R² = 0.0084). Multivariate regression analyses of n-6 FA intakes in quartiles showed that, compared with the lowest quartile (179.8–1150.3 mg), those in the highest quartile (2315.0–7449.4 mg) had a total ARCS score 2.1 units greater (RC = 10.60466; p = 0.006; R² = 0.0081). Furthermore, when n-6 FA intake was tested against each of the ARCS domains, statistically significant associations were observed for the Fluency (RC = 0.0011432; p = 0.007; R² = 0.0057), Visual (RC = 0.0009889; p = 0.034; R² = 0.0050), Language (RC = 0.0010651; p = 0.047; R² = 0.0068) and Attention (RC = 0.0011605; p = 0.017; R² = 0.0099) domains, yet there was no association with Memory (RC = −0.000064; p = 0.889; R² = 0.0083). No statistically significant associations were observed between FA intakes and MMSE. A higher intake of total n-6 FA, but not other types of FA, was associated with better cognitive performance among a representative sample of older aged Australian adults.

Unsaturated Fatty Acid Intakes During Midlife Are Positively Associated with Later Cognitive Function in Older Adults with Modulating Effects of Antioxidant Supplementation

Background

Given the drastic demographic changes characterized as "population aging," the disease burden related to dementia is a major public health problem. The scientific literature documenting the link between mono- and polyunsaturated fatty acids (MUFAs, PUFAs) and cognitive function during aging is plentiful, but findings are inconsistent.

Objectives

We aimed to evaluate the association between intakes of unsaturated fatty acids at midlife and cognitive performance 13 y later in French adults, and to test for a modulating effect of antioxidant supplementation.

Methods

Fatty acid intakes were estimated with the use of repeated 24-h records (1994-1996) among 3362 subjects (mean ± SD age: 65.5 ± 4.6 y) of the SU.VI.MAX (Supplementation with Antioxidant Vitamins and Minerals) study, including an intervention phase (1994-2002) during which participants were randomly assigned to an "antioxidant supplementation" or placebo group. Cognitive performance was assessed at follow-up only (in 2007-2009) via a battery of 6 standardized neuropsychological tests. A global cognitive score was calculated as the sum of T-scores of the 6 tests. Multivariable-adjusted regression analyses were performed to provide regression coefficients and 95% CIs.

Results

In multivariable models, total MUFAs, total PUFAs, and n-6 PUFAs (ω-6 PUFAs) were positively associated with overall cognitive functioning. n-3 PUFA (ω-3 PUFA) intakes showed positive associations among supplemented participants only (mean difference Tertile3 versus Tertile1: 1.40; 95% CI: 0.30, 2.51; P-trend = 0.01, P-interaction = 0.01). A detrimental role of arachidonic acid for cognitive functioning was only detected in the placebo group (mean difference Tertile3 versus Tertile1: -1.38; 95% CI: -2.57, -0.18; P-trend = 0.02, P-interaction = 0.07).

Conclusion

Whereas higher total MUFA and n-6 PUFA intakes may be generally beneficial for maintaining cognitive health during aging, a higher consumption of n-3 fatty acids may only be beneficial among individuals with an adequate antioxidant status. These findings underline the importance of not only focusing on specific nutrients for dementia prevention, but also considering the complex interaction between consumed nutrients. This trial was registered at clinicaltrials.gov as NCT00272428.

Neuro-nutrients as anti-alzheimer's disease agents: A critical review

Alzheimer's disease (AD) is characterized by a massive neuronal death causing memory loss, cognitive impairment and behavioral alteration that ultimately lead to dementia and death. AD is a multi-factorial pathology controlled by molecular events such as oxidative stress, protein aggregation, mitochondrial dysfunction and neuro inflammation. Nowadays, there is no efficient disease-modifying treatment for AD and epidemiological studies have suggested that diet and nutrition have a significant impact on the development of this disorder. Indeed, some nutrients can protect all kind of cells, including neurons. As prevention is better than cure, life style improvement, with a special emphasis on diet, should seriously be considered as an anti-AD track and intake of nutrients promoting neuronal health is the need of the hour. Diets rich in unsaturated fatty acids, polyphenols and vitamins have been shown to protect against AD, whereas saturated fatty acids-containing diets deprived of polyphenols promote the development of the disease. Thus, Mediterranean diets, mainly composed of fruits, vegetables and omega-3 fatty acids, stand as valuable, mild and preventive anti-AD agents. This review focuses on our current knowledge in the field and how one can fight this devastating neurodegenerative disorder through the simple proper modification of our life style.

Relationship between Adherence to the Mediterranean Diet and Health-Related Quality of Life and Life Satisfaction among Older Adults

OBJECTIVES

Evaluate the relationship between adherence to the Mediterranean diet and health-related quality of life and degree of life satisfaction among older adults.

DESIGN AND SETTING

Cross-sectional descriptive study.

PARTICIPANTS

A total of 351 people older than 60 years participated in the study.

MEASUREMENTS

The Mediterranean Diet Score (MDS) was calculated to assess the degree of adherence to the MD. MD adherence was related to health-related quality of life using the Short Form Healthy Survey (SF-12) questionnaire, to life satisfaction using the Satisfaction with Life Scale (SWLS), and to sociodemographic, clinical and lifestyle variables. Multiple logistic regression models were used to analyse this relationship.

RESULTS

Mediterranean diet adherence was related to health- related quality of life. Participants with better adherence to the MD were more physically active (p=0.01) and had better health-related quality of life (p<0.05) and lower consumption of alcoholic beverages (p=0.04). The age-adjusted model showed a significant association between the MD and mental function for both sexes and with physical function only for men. The fully adjusted model showed a direct relationship between the MD and life satisfaction of women (p>0.05) but not for that of men (p=0.31).

CONCLUSIONS

The adherence to the MD is directly associated with the self-perceived physical and mental function of both sexes and with the life satisfaction of women. Further studies in older adult populations should be performed to obtain conclusive results on the MD effect on health-related quality of life, including wellness indicators.

Adherence to Mediterranean diet and subjective cognitive function in men

Benefits of a Mediterranean diet for cognition have been suggested, but epidemiologic studies have been relatively small and of limited duration. To prospectively assess the association between long-term adherence to a Mediterranean dietary pattern and self-reported subjective cognitive function (SCF). Prospective observational study. The Health Professionals' Follow-up Study, a prospective cohort of 51,529 men, 40-75 years of age when enrolled in 1986, of whom 27,842 were included in the primary analysis. Mediterranean diet (MD) score, computed from the mean of five food frequency questionnaires, assessed every 4 years from 1986 to 2002. Self-reported SCF assessed by a 6-item questionnaire in 2008 and 2012, and validated by association with genetic variants in apolipoprotein-4. Using the average of 2008 and 2012 SCF scores, 38.0% of men were considered to have moderate memory scores and 7.3% were considered to have poor scores. In a multivariate model, compared with men having a MD score in the lowest quintile, those in the highest quintile had a 36% lower odds of a poor SCF score (odds ratio 0.64, 95% CI 0.55-0.75; P, trend < 0.001) and a 24% lower odds of a moderate SCF score (OR 0.76, 95% CI 0.70-0.83; P, trend < 0.001). Both remote and more recent diet contributed to this relation. Associations were only slightly weaker using baseline dietary data and a lag of 22 years. Long-term adherence to the Mediterranean diet pattern was strongly related to lower subjective cognitive function. These findings provide further evidence that a healthy dietary pattern may prevent or delay cognitive decline.

Nutrient intake, nutritional status, and cognitive function with aging

With the demographic aging of populations worldwide, diseases associated with aging are becoming more prevalent and costly to individuals, families, and healthcare systems. Among aging-related impairments, a decline in cognitive function is of particular concern, as it erodes memory and processing abilities and eventually leads to the need for institutionalized care. Accumulating evidence suggests that nutritional status is a key factor in the loss of cognitive abilities with aging. This is of tremendous importance, as dietary intake is a modifiable risk factor that can be improved to help reduce the burden of cognitive impairment. With respect to nutrients, there is evidence to support the critical role of several B vitamins in particular, but also of vitamin D, antioxidant vitamins (including vitamin E), and omega-3 fatty acids, which are preferentially taken up by brain tissue. On the other hand, high intakes of nutrients that contribute to hypertension, atherosclerosis, and poor glycemic control may have negative effects on cognition through these conditions. Collectively, the evidence suggests that considerable slowing and reduction of cognitive decline may be achieved by following a healthy dietary pattern, which limits intake of added sugars, while maximizing intakes of fish, fruits, vegetables, nuts, and seeds.

Comparison of the effects of major fatty acids present in the Mediterranean diet (oleic acid, docosahexaenoic acid) and in hydrogenated oils (elaidic acid) on 7-ketocholesterol-induced oxiapoptophagy in microglial BV-2 cells

Increased levels of 7-ketocholesterol (7KC), which results mainly from cholesterol auto-oxidation, are often found in the plasma and/or cerebrospinal fluid of patients with neurodegenerative diseases and might contribute to activation of microglial cells involved in neurodegeneration. As major cellular dysfunctions are induced by 7KC, it is important to identify molecules able to impair its side effects. Since consumption of olive and argan oils, and fish is important in the Mediterranean diet, the aim of the study was to determine the ability of oleic acid (OA), a major compound of olive and argan oil, and docosahexaenoic acid (DHA) present in fatty fishes, such as sardines, to attenuate 7KC-induced cytotoxic effects. Since elaidic acid (EA), the trans isomer of OA, can be found in hydrogenated cooking oils and fried foods, its effects on 7KC-induced cytotoxicity were also determined. In murine microglial BV-2 cells, 7KC induces cell growth inhibition, mitochondrial dysfunctions, reactive oxygen species overproduction and lipid peroxidation, increased plasma membrane permeability and fluidity, nuclei condensation and/or fragmentation and caspase-3 activation, which are apoptotic characteristics, and an increased LC3-II/LC3-I ratio, which is a criterion of autophagy. 7KC is therefore a potent inducer of oxiapoptophagy (OXIdation+APOPTOsis+autoPHAGY) on BV-2 cells. OA and EA, but not DHA, also favor the accumulation of lipid droplets revealed with Masson's trichrome, Oil Red O, and Nile Red staining. The cytotoxicity of 7KC was strongly attenuated by OA and DHA. Protective effects were also observed with EA. However, 7KC-induced caspase-3 activation was less attenuated with EA. Different effects of OA and EA on autophagy were also observed. In addition, EA (but not OA) increased plasma membrane fluidity, and only OA (but not EA) was able to prevent the 7KC-induced increase in plasma membrane fluidity. Thus, in BV-2 microglial cells, the principal fatty acids of the Mediterranean diet (OA, DHA) were able to attenuate the major toxic effects of 7KC, thus reinforcing the interest of natural compounds present in the Mediterranean diet to prevent the development of neurodegenerative diseases.

APP Function and Lipids: A Bidirectional Link

Extracellular neuritic plaques, composed of aggregated amyloid-β (Aβ) peptides, are one of the major histopathological hallmarks of Alzheimer's disease (AD), a progressive, irreversible neurodegenerative disorder and the most common cause of dementia in the elderly. One of the most prominent risk factor for sporadic AD, carrying one or two aberrant copies of the apolipoprotein E (ApoE) ε4 alleles, closely links AD to lipids. Further, several lipid classes and fatty acids have been reported to be changed in the brain of AD-affected individuals. Interestingly, the observed lipid changes in the brain seem not only to be a consequence of the disease but also modulate Aβ generation. In line with these observations, protective lipids being able to decrease Aβ generation and also potential negative lipids in respect to AD were identified. Mechanistically, Aβ peptides are generated by sequential proteolytic processing of the amyloid precursor protein (APP) by β- and γ-secretase. The α-secretase appears to compete with β-secretase for the initial cleavage of APP, preventing Aβ production. All APP-cleaving secretases as well as APP are transmembrane proteins, further illustrating the impact of lipids on Aβ generation. Beside the pathological impact of Aβ, accumulating evidence suggests that Aβ and the APP intracellular domain (AICD) play an important role in regulating lipid homeostasis, either by direct effects or by affecting gene expression or protein stability of enzymes involved in the de novo synthesis of different lipid classes. This review summarizes the current literature addressing the complex bidirectional link between lipids and AD and APP processing including lipid alterations found in AD post mortem brains, lipids that alter APP processing and the physiological functions of Aβ and AICD in the regulation of several lipid metabolism pathways.

A Mediterranean Diet to Improve Cardiovascular and Cognitive Health: Protocol for a Randomised Controlled Intervention Study

The Mediterranean diet has demonstrated efficacy for improving cardiovascular and cognitive health. However, a traditional Mediterranean diet delivers fewer serves of dairy and less dietary calcium than is currently recommended in Australia, which may limit long-term sustainability. The present study aims to evaluate whether a Mediterranean diet with adequate dairy and calcium can improve cardiovascular and cognitive function in an at-risk population, and thereby reduce risk of cardiovascular disease (CVD) and cognitive decline. A randomised, controlled, parallel, crossover design trial will compare a Mediterranean diet supplemented with dairy foods against a low-fat control diet. Forty participants with systolic blood pressure above 120 mmHg and at least two other risk factors of CVD will undertake each dietary intervention for eight weeks, with an eight-week washout period between interventions. Systolic blood pressure will be the primary measure of interest. Secondary outcomes will include measures of cardiometabolic health, dietary compliance, cognitive function, assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB), psychological well-being and dementia risk. This research will provide empirical evidence as to whether the Mediterranean diet can be modified to provide recommended dairy and calcium intakes while continuing to deliver positive effects for cardiovascular and cognitive health. The findings will hold relevance for the field of preventative healthcare and may contribute to revisions of national dietary guidelines.

A Bidirectional Relationship between Executive Function and Health Behavior: Evidence, Implications, and Future Directions

Physically active lifestyles and other health-enhancing behaviors play an important role in preserving executive function into old age. Conversely, emerging research suggests that executive functions facilitate participation in a broad range of healthy behaviors including physical activity and reduced fatty food, tobacco, and alcohol consumption. They do this by supporting the volition, planning, performance monitoring, and inhibition necessary to enact intentions and override urges to engage in health damaging behavior. Here, we focus firstly on evidence suggesting that health-enhancing behaviors can induce improvements in executive function. We then switch our focus to findings linking executive function to the consistent performance of health-promoting behaviors and the avoidance of health risk behaviors. We suggest that executive function, health behavior, and disease processes are interdependent. In particular, we argue that a positive feedback loop may exist whereby health behavior-induced changes in executive function foster subsequent health-enhancing behaviors, which in turn help sustain efficient executive functions and good health. We conclude by outlining the implications of this reciprocal relationship for intervention strategies, the design of research studies, and the study of healthy aging.

Is the Mediterranean diet a feasible approach to preserving cognitive function and reducing risk of dementia for older adults in Western countries? New insights and future directions

The rise in the ageing population has resulted in increased incident rates of cognitive impairment and dementia. The subsequent financial and societal burden placed on an already strained public health care system is of increasing concern. Evidence from recent studies has revealed modification of lifestyle and dietary behaviours is, at present, the best means of prevention. Some of the most important findings, in relation to the Mediterranean diet (MedDiet) and the contemporary Western diet, and potential molecular mechanisms underlying the effects of these two diets on age-related cognitive function, are discussed in this review. A major aim of this review was to discuss whether or not a MedDiet intervention would be a feasible preventative approach against cognitive decline for older adults living in Western countries. Critical appraisal of the literature does somewhat support this idea. Demonstrated evidence highlights the MedDiet as a potential strategy to reduce cognitive decline in older age, and suggests the Western diet may play a role in the aetiology of cognitive decline. However, strong intrinsic Western socio-cultural values, traditions and norms may impede on the feasibility of this notion.

Sex-Specific Effects of Diets High in Unsaturated Fatty Acids on Spatial Learning and Memory in Guinea Pigs

Unsaturated fatty acids (UFAs), including omega-3, omega-6 polyunsaturated and omega-9 monounsaturated fatty acids, are essential components and modulators of neuromembranes and may affect various aspects of physiology and cognition. UFAs are suggested to positively affect spatial learning and memory and also to diminish the negative consequences of physiological stress on cognitive abilities. Due to pronounced sex differences in neurophysiological functions, we hypothesize that these UFA-related effects might differ between male and female individuals. We therefore determined the effects of dietary UFAs on cognitive performances in a radial-Y-maze in male and female guinea pigs in relation to saliva cortisol concentrations, a marker for physiological stress. Animals were assigned to four treatment groups and maintained on diets enriched in either chia seeds (omega-3), walnuts (omega-6), or peanuts (omega-9), or a control diet. Female learning abilities throughout a three-day learning phase were positively affected by omega-3 and omega-9, as determined by a decreasing latency to pass the test and the number of conducted errors, while males generally showed distinct learning abilities, irrespective of the diet. A sex difference in learning performances was found in the control group, with males outperforming females, which was not detected in the UFA-supplemented groups. This was paralleled by significantly increased saliva cortisol concentrations in males throughout the cognition test compared to females. Three days after this learning phase, UFA-supplemented males and all females showed unchanged performances, while control males showed an increased latency and therefore an impaired performance. These results were corroborated by pronounced differences in the plasma UFA-status, corresponding to the different dietary treatments. Our findings indicate sex-specific effects of dietary UFAs, apparently enhancing spatial learning abilities only in females and protecting males from long-term memory impairment, while male learning abilities seem to be more strongly affected by an acute physiological stress response to the maze task.

Diet, Alcohol Consumption and Cognitive Disorders in Central Africa: A Study from the EPIDEMCA Program

Western research into dementia has focused on finding effective means of prevention, particularly through nutrition. To date, however, little is known about the relationship between diet and cognitive disorders in Africa, where the number of people with dementia is expected to increase most over the coming decades. The objective of the study was to investigate the relationship between diet and alcohol intake and cognitive disorders among elderly people in Central Africa. Between 2011 and 2012, a cross-sectional multicentre population-based study was carried out in rural and urban areas of the Central African Republic (CAR) and the Republic of Congo (ROC). Participants aged ≥65 years were interviewed using the Community Screening Interview for Dementia (CSI-D). Elderly people who performed poorly (COGSCORE≤24.5/30) were clinically assessed by neurologists and underwent further psychometric testing. DSM-IV and Petersen criteria were required for a diagnosis of dementia or mild cognitive impairment (MCI), respectively. A food frequency questionnaire assessed the intakes of dairy products, fruit, vegetables, starches, legumes, oleaginous foods, meat or fish, eggs and sweet foods over the previous three days. We also collected data on alcohol intake. Sociodemographic, vascular, and psychological factors were documented. Multivariate multinomial logistic regression models were used to estimate the associations. In fully adjusted models, a lower consumption of oleaginous foods was associated with MCI (OR=3.7 [1.4-9.9]) and dementia (OR=2.8 [1.0-7.7]) in a rural area of CAR. Alcohol consumption was associated with reduced probability of dementia in CAR (OR=0.3 [0.1-0.8]). In ROC, food groups and alcohol intake were not associated with MCI or dementia. In conclusion, our study provides new data about the association between diet and cognitive disorders in Africa. Further studies should investigate the relationship between diet and cognitive disorders at the level of specific foods rather than food groups.

The association of healthful diets and cognitive function: a review

The association of diet with mild cognitive impairment has not been extensively studied. Consumption of a healthful diet may help to attenuate age-related decline in older adults. Published studies have suggested that greater adherence to a Mediterranean-style dietary pattern is associated with a lower risk of developing Alzheimer's disease and with a slower rate of cognitive decline with age. However, published findings are inconsistent. The discrepancies most likely can be explained by the variations in both dietary and cognitive methodologies. It is not clear how diet contributes to the development of neurocognitive changes with age. This review will update available knowledge on the relationship between adherence to healthful diets and cognition and document the need for researchers to adopt more coherent and uniform methodology to allow for better quantification of the association of diet with cognitive function. There appears to be a relationship between diet and cognition.

Target risk factors for dementia prevention: a systematic review and Delphi consensus study on the evidence from observational studies

OBJECTIVE

Dementia has a multifactorial etiology, but the importance of individual health and lifestyle related risk factors is often uncertain or based on few studies. The goal of this paper is to identify the major modifiable risk factors for dementia as a first step in developing an effective preventive strategy and promoting healthy late life cognitive functioning.

METHODS

A mixed-method approach combined findings from a systematic literature review and a Delphi consensus study. The literature search was conducted in PubMed and updated an earlier review by the United States National Institutes of Health from 2010. We reviewed the available evidence from observational epidemiological studies. The online Delphi study asked eight international experts to rank and weigh each risk factor for its importance for dementia prevention.

RESULTS

Out of 3127 abstracts, 291 were included in the review. There was good agreement between modifiable risk factors identified in the literature review and risk factors named spontaneously by experts. After triangulation of both methods and re-weighting by experts, strongest support was found for depression, (midlife) hypertension, physical inactivity, diabetes, (midlife) obesity, hyperlipidemia, and smoking, while more research is needed for coronary heart disease, renal dysfunction, diet, and cognitive activity.

CONCLUSIONS

Findings provide good support for several somatic and lifestyle factors and will be used to inform the design of a new multicenter trial into dementia prevention.

Fatty acid status and its relationship to cognitive decline and homocysteine levels in the elderly

Polyunsaturated fatty acids (PUFAs), especially the n-3 series, are known for their protective effects. Considering that cardiovascular diseases are risk factors for dementia, which is common at aging, the aim of this study was to evaluate whether fatty acid status in the elderly was associated with cognitive function and cardiovascular risk. Forty-five elderly persons (age ≥60 years) were included and divided into two groups based on their Mini-Mental Status Examination score adjusted for educational level: the case group (n = 12) and the control group (n = 33). Serum fatty acid composition, homocysteine (Hcy), hs-CRP, lipid profile and different cognitive domains were evaluated. The case group, characterized by reduced cognitive performance, showed higher levels of 14:0, 16:0, 16:1n-7 fatty acids and lower levels of 22:0, 24:1n-9, 22:6n-3 (DHA) and total PUFAs compared to the control group (p < 0.05). The n-6/n-3 ratio was elevated in both study groups, whereas alterations in Hcy, hs-CRP and lipid profile were observed in the case group. Cognitive function was positively associated with the 24:1n-9, DHA and total n-3 PUFAs, while 14:0, 16:0 and 16:1n-7 fatty acids, the n-6/n-3 ratio and Hcy were inversely associated. In addition, n-3 PUFAs, particularly DHA, were inversely associated with cardiovascular risk, assessed by Hcy levels in the elderly.

Dietary fat composition and dementia risk

This is a qualitative review of the evidence linking dietary fat composition to the risk of developing dementia. The review considers laboratory and animal studies that identify underlying mechanisms as well as prospective epidemiologic studies linking biochemical or dietary fatty acids to cognitive decline or incident dementia. Several lines of evidence provide support for the hypothesis that high saturated or trans fatty acids increase the risk of dementia and high polyunsaturated or monounsaturated fatty acids decrease risk. Dietary fat composition is an important factor in blood-brain barrier function and the blood cholesterol profile. Cholesterol and blood-brain barrier function are involved in the neuropathology of Alzheimer's disease, and the primary genetic risk factor for Alzheimer's disease, apolipoprotein E-ε4, is involved in cholesterol transport. The epidemiologic literature is seemingly inconsistent on this topic, but many studies are difficult to interpret because of analytical techniques that ignored negative confounding by other fatty acids, which likely resulted in null findings. The studies that appropriately adjust for confounding by other fats support the dietary fat composition hypothesis.

Saturated and trans fats and dementia: a systematic review

Cognitive disorders of later life are potentially devastating. To estimate the relationship between saturated and trans fat intake and risk of cognitive disorders. PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials were searched for studies reporting saturated or trans fat intake and incident dementia, Alzheimer's disease (AD), or mild cognitive impairment (MCI) or cognitive decline. Only observational studies met the inclusion criteria: 4 for AD or other dementias, 4 for MCI, and 4 for cognitive decline. Saturated fat intake was positively associated with AD risk in 3 of 4 studies, whereas the fourth suggested an inverse relationship. Saturated fat intake was also positively associated with total dementia in 1 of 2 studies, with MCI in 1 of 4 studies, and with cognitive decline in 2 of 4 studies. Relationships between trans fat intake and dementia were examined in 3 reports with mixed results. Several, although not all, prospective studies indicate relationships between saturated and trans fat intake and risk of cognitive disorders.