Dietary fat composition and dementia risk

Dietary lipophilic index and odds of metabolic dysfunction-associated steatotic liver disease (MASLD): A population-based study

INTRODUCTION

Non-alcoholic fatty liver disease (MASLD) is one of the highly prevalent metabolic disorders worldwide The present study aimed to determine the association between a novel dietary lipophilic index (LI) with metabolic profile and MASLD in a population-based study in Amol, Iran.

PATIENTS AND METHODS

A cross-sectional study was conducted among 2979 Iranian adults within the framework of the Amol cohort study (AmolCS) Dietary assessments were performed using a validated 168-item food frequency questionnaire (FFQ) The dietary fatty acids were determined using the food composition table in Food Data Central of the USDA to indicate the lipophilic index Information about the melting point of fatty acids was obtained from the lipid bank database MASLD was defined as the ultrasound detection of hepatic steatosis that ruled out other causes of hepatic fat accumulation Then, dietary LI and lipophilic load (LL) were calculated using dietary fatty acid intake and melting point Multivariate MASLD The analysis was carried out for all participants stratified by sex and BMI Potential confounders were included in three different adjusted models.

RESULTS

The results revealed that dietary LI was associated with higher BMI and (WHtR), low physical activity, being female, living in urban residencies, and diabetes After adjustment for potential confounders, age, and energy intake, the odds ratio of MASLD in women was 1.33 (95 % CI: 1.05-1.99, p = 0.048) in the last tertile of dietary LI compared to the first tertile In adjustment by age and energy intake, chronic disease, smoking, physical activity, waist circumference, and residency women have a higher chance of MASLD in the second tertile of dietary LI (OR:1.38 95 % CI: 1.01-1.89) as well as in the third LI (OR:1.39, 95 % CI: 1.02-1.91) compared to the first tertile When the body mass index (BMI) was added to other confounders variables, the odds ratio of MASLD was 1.44 (95 % CI: 1.05-1.99) in the second tertile of LI and 1.41(95 % CI:1.02-1.95) in the third tertiles, Ptrend=0.04 In normal weight participants (BMI< 25), after adjustment for age and energy intake, the odds of MASLD were 86 % higher (CI; 1.07-3.25, Ptrend< 0.03) in the last tertile of LL compared to the first one.

CONCLUSIONS

This study found that higher levels of dietary fatty acids are associated with 40 % higher odds of MASLD in women Additionally, higher levels of fatty acids in normal-weight individuals were linked to an 86 % higher chance of MASLD It is highly recommended to reduce intake of saturated fatty acids and trans fatty acids, which are associated with a lower risk of MASLD.

A review on gut microbiota and miRNA crosstalk: implications for Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline and progressive neuronal damage. Recent research has highlighted the significant roles of the gut microbiota and microRNAs (miRNAs) in the pathogenesis of AD. This review explores the intricate interaction between gut microbiota and miRNAs, emphasizing their combined impact on Alzheimer's progression. First, we discuss the bidirectional communication within the gut-brain axis and how gut dysbiosis contributes to neuroinflammation and neurodegeneration in AD. Changes in gut microbiota composition in Alzheimer's patients have been linked to inflammation, which exacerbates disease progression. Next, we delve into the biology of miRNAs, focusing on their roles in gene regulation, neurodevelopment, and neurodegeneration. Dysregulated miRNAs are implicated in AD pathogenesis, influencing key processes like inflammation, tau pathology, and amyloid deposition. We then examine how the gut microbiota modulates miRNA expression, particularly in the brain, potentially altering neuroinflammatory responses and synaptic plasticity. The interplay between gut microbiota and miRNAs also affects blood-brain barrier integrity, further contributing to Alzheimer's pathology. Lastly, we explore therapeutic strategies targeting this gut microbiota-miRNA axis, including probiotics, prebiotics, and dietary interventions, aiming to modulate miRNA expression and improve AD outcomes. While promising, challenges remain in fully elucidating these interactions and translating them into effective therapies. This review highlights the importance of understanding the gut microbiota-miRNA relationship in AD, offering potential pathways for novel therapeutic approaches aimed at mitigating the disease's progression.

Rescue of hippocampal synaptic plasticity and memory performance by Fingolimod (FTY720) in APP/PS1 model of Alzheimer's disease is accompanied by correction in metabolism of sphingolipids, polyamines, and phospholipid saturation composition

Previously, our metabolomic, transcriptomic, and genomic studies characterized the ceramide/sphingomyelin pathway as a therapeutic target in Alzheimer's disease, and we demonstrated that FTY720, a sphingosine-1-phospahate receptor modulator approved for treatment of multiple sclerosis, recovers synaptic plasticity and memory in APP/PS1 mice. To further investigate how FTY720 rescues the pathology, we performed metabolomic analysis in brain, plasma, and liver of trained APP/PS1 and wild-type mice. APP/PS1 mice showed area-specific brain disturbances in polyamines, phospholipids, and sphingolipids. Most changes were completely or partially normalized in FTY720-treated subjects, indicating rebalancing the "sphingolipid rheostat", reactivating phosphatidylethanolamine synthesis via mitochondrial phosphatidylserine decarboxylase pathway, and normalizing polyamine levels that support mitochondrial activity. Synaptic plasticity and memory were rescued, with spermidine synthesis in temporal cortex best corresponding to hippocampal CA3-CA1 plasticity normalization. FTY720 effects, also reflected in other pathways, are consistent with promotion of mitochondrial function, synaptic plasticity, and anti-inflammatory environment, while reducing pro-apoptotic and pro-inflammatory signals.

Cancer-Related Cognitive Impairment and the Potential of Dietary Interventions for the Prevention and Mitigation of Neurodegeneration

Approximately 35% of long-term cancer survivors experience ongoing cancer-related cognitive impairment (CRCI). Yet, few efficacious interventions exist to prevent or ameliorate CRCI. The underlying biological processes driving CRCI are complex and are reported to include changes in brain structure and function, increased oxidative stress and inflammation, and alterations in gut microbiome composition. Some of the mechanisms promoting CRCI have the potential to be modified through behavioral changes, such as dietary changes. Compelling evidence from randomized controlled trials and observational research supports the positive impacts of the Mediterranean-DASH Intervention for Neurodegenerative Delay diet on cognition outside of the context of cancer, but studies investigating the Mediterranean-DASH Intervention for Neurodegenerative Delay diet as an intervention for people who experience CRCI are lacking. This review examines the current state of the science for cognitive outcomes of dietary interventions in aging populations and discusses future opportunities to adapt these interventions to cancer populations.

The relationship between levels of physical activity, adherence to the MIND diet, and cognitive impairment in adults aged 65 years or older in Pakistan

Background

In contrast to existing evidence focusing on high-income countries, this study offers novel insights into the demographic and geographical context that have yet to be explored in the existing literature. Comparatively, in Pakistan, cognitive impairment is one of the neglected disorders that can develop into dementia and Alzheimer's disease. As no treatment is available, lifestyle modifications are a valid intervention for cognitive health.

Objective

This study aimed to assess the relationship between physical functionality, adherence to the Mediterranean-DASH diet Intervention for Neurological Delay (MIND), and cognitive impairment among elderly individuals in Pakistan.

Methods

From January to June 2023, this cross-sectional study recruited 462 participants aged 65 and above. We used proven tools in gerontological research, such as the MIND diet quiz and Quick Physical Activity Rating scale (QPAR), to evaluate diet and physical activity levels. Cognitive function was assessed using the Mini-Mental State Examination.

Results

Our analysis revealed that 26.40% of the participants had mild cognitive impairment, whereas 48.50% demonstrated low adherence to the MIND diet. The mean QPAR score was 20.51 ± 18.77. A significant association was found between lower physical activity levels and increased cognitive impairment (adjusted odds ratio 9.94, confidence interval (CI): 6.07-16.27). Additionally, higher adherence to the MIND diet correlated with reduced cognitive impairment (odds ratio 0.29, CI: 0.18-0.46).

Conclusions

These findings highlight the critical role of diet and physical activity in cognitive health among the elderly population. The study emphasizes the need for targeted public health interventions and further longitudinal research to explore the long-term effects of these factors on cognitive health.

Development of the Dutch Mediterranean-Dietary Approaches to Stop Hypertension Intervention for Neurodegenerative Delay (MIND) Diet and its scoring system, alongside the modification of a brief FFQ for assessing dietary adherence

The Mediterranean-Dietary Approach to Stop Hypertension (DASH) Intervention for Neurodegenerative Delay (MIND) diet is a dietary pattern designed to prevent cognitive decline. Dietary adherence is assessed with the MIND diet scoring system, which is currently based on the American diet and serving sizes. It is known that serving sizes and consumed food products differ between countries. Existing literature lacks reporting on food products included within the MIND diet and weight or volume equivalents corresponding to MIND diet servings, impeding accurate comparisons across studies. This study sought to overcome these limitations by evaluating MIND food products consumed in the Dutch context and developing a scoring system based on consumed quantities in weight or volume amounts rather than in standard serving amounts. The third objective was to modify an existing Dutch brief FFQ (Eetscore-FFQ) to evaluate adherence to the MIND diet. We translated nine of the fifteen MIND food groups directly to grams and volumes using the United States Department of Agriculture measurement conversion table. For the remaining food groups, we employed indirect translation to align them as closely as possible to the original MIND diet. These translated quantities in weight and volumes amounts were subsequently rounded to the nearest Dutch household measures, resulting in the culturally adapted MIND-NL diet scoring. The development of the MIND-NL-Eetscore-FFQ, comprising seventy-two food items (forty-one questions), is described. Our adaption approach is reproducible and can be used to customize the MIND diet scoring system to other cultures.

Comparison of diet quality indices for predicting metabolic syndrome in Iran: cross-sectional findings from the persian cohort study

BACKGROUND

The metabolic syndrome (MetS) comprises metabolic irregularities, including hypertension and central obesity, which are influenced by genetic, metabolic, environmental, and dietary factors. As diet and lifestyle are risk factors for MetS, it is important to know which diet quality index better predicts MetS. The aim of this study is to compare the ability of different diet quality indices in predicting MetS and to identify the most effective one.

METHODS

This cross-sectional study involved 5,206 participants aged 35 to 70 engaged in the Prospective Epidemiological Research Study in Iran (PERSIAN) cohort. Assessment of one year's food intake via a validated 134-item semi-quantitative food frequency questionnaire (FFQ) facilitated the calculation of adherence to five diet quality indices: Dietary Approaches to Stop Hypertension (DASH), Mediterranean, Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND), Dietary Inflammatory Index (DII), and Diet Quality Indices (DQI). While bivariate Pearson correlation and binary logistic regression aided in identifying the strongest correlation and predictor for MetS among the indices.

RESULTS

This study showed a significant association between adhering to the DASH diet score, Mediterranean diet score, MIND diet score, DII score, and DQI score, and the odds of developing MetS (OR: 0.94, (95% CI: 0.93-0.95), OR: 0.85, (95% CI: 0.81-0.89), OR: 0.84, (95% CI: 0.80-0.89), OR: 1.22, (95%CI: 1.11-1.34), OR: 0.95, (95%CI 0.94-0.96) respectively). Therefore, with each unit increase in DASH diet score, Mediterranean diet score, MIND diet score, DII score, and DQI score, the odds of MetS was reduced by 5.4%, 14.5%, 15.6%, 22%, 5%, respectively. All the indices were correlated with the intake of most of the micronutrients, with the strongest correlations being observed in the DII. DASH diet score aligned with the most favourable MetS biomarker risk, while DII score primarily associated with MetS and could be considered as a predictor for MetS.

CONCLUSION

The present study's findings reveal that between all these five diet quality indices, the DASH diet score correlates strongly with a favourable biomarker risk profile, while the DII score is predominantly linked to MetS.

The impact of MIND diet consumption and physical activity on cognitive functioning in healthy aging older adults

Objective: Modifiable lifestyle factors evidence great promise in reducing cognitive decline in older adults. Greater consumption to the MIND diet (Morris et al.) and increased daily physical activity (Buchman et al.) are associated with higher cognitive functioning. The interactive effects of lifestyle factors on cognition in older adults has not been investigated extensively. The present study examined the interaction between MIND diet consumption and intensity of physical activity on cognition in community-dwelling older adults. Methods: The sample included 215 older adults (159 female, Mage=79.8; Medu=15.5) from the Memory and Aging Project (Bennet et al.). The measures included the food frequency questionnaire (FFQ, MIND diet consumption), a portable actigraph worn 24 h a day for ten days (activity intensity), and a neuropsychological battery (cognitive variables). Results: Controlling for age and education, multiple regression analyses revealed that MIND diet consumption significantly predicted global cognition (ps< .05). Physical activity significantly predicted global cognition (ps< .05), and processing speed (ps< .01). Interaction effects were significant in global cognition (ps< .05), and episodic memory (ps< .01) revealing a pattern that those with the lowest MIND diet consumption may experience greater cognitive benefits from physical activity in than those with higher diet consumption. Conclusions: Findings suggest that older adults who do not consume the MIND diet closely may experience greater benefit in cognitive functioning from exercise than individuals who more greatly consume the diet.

Plasma proteomics and lipidomics facilitate elucidation of the link between Alzheimer's disease development and vessel wall fragility

Proximity Extension Assay (PEA) and mass spectrometry (MS) methodologies were utilized for the proteomic and lipidomic characterization of plasma specimens from patients who developed Alzheimer's disease. Proteomics was performed by both PEA and Liquid Chromatography (LC)/MS in this study, but all the more because LC/MS generally tends to be biased towards proteins with high expression and high variability, generating hypotheses proved challenging. Consequently, attempt was made to interpret the results from the PEA data. There were 150 significantly variable proteins and 68 lipids among 1000 proteins and 400 lipids. Pathway analysis was performed for both total and variable proteins measured to reduce bias, and it appeared that vascular fragility was related to AD. Furthermore, a multitude of lipid-associated proteins exhibited statistical changes. In certain instances, the function of individual proteins affected the factors associated with them, whereas others demonstrated trends contrary to anticipated outcomes. These trends seem indicative of diverse feedback mechanisms that provide homeostatic equilibrium. The degree of unsaturation of fatty acids, correlated with cardiovascular risk, warrants specific attention. Certain bile acids exhibited the potential to cause vascular endothelial damage. Contemplating these discoveries in tandem with previously documented phenomena, subtle shifts in homeostatic functions seem to be linked to the fragility of vascular endothelial cells. This is evidenced by the slow and chronic evolution of Alzheimer's disease from preclinical stages to its manifestation.

Intergenerational epigenetic inheritance mediated by MYS-2/MOF in the pathogenesis of Alzheimer's disease

Although autosomal-dominant inheritance is believed an important cause of familial clustering Alzheimer's disease (FAD), it covers only a small proportion of FAD incidence, and so we investigated epigenetic memory as an alternative mechanism to contribute for intergenerational AD pathogenesis. Our data in vivo showed that mys-2 of Caenorhabditis elegans that encodes a putative MYST acetyltransferase responsible for H4K16 acetylation modulated AD occurrence. The phenotypic improvements in the parent generation caused by mys-2 disfunction were passed to their progeny due to epigenetic memory, which resulted in similar H4K16ac levels among the candidate target genes of MYS-2 and similar gene expression patterns of the AD-related pathways. Furthermore, the ROS/CDK-5/ATM pathway functioned as an upstream activator of MYS-2. Our study indicated that MYS-2/MOF could be inherited intergenerationally via epigenetic mechanisms in C. elegans and mammalian cell of AD model, providing a new insight into our understanding of the etiology and inheritance of FAD.

Effects of MIND diet and propolis supplementation on metabolic syndrome indices and cognitive function among patients with metabolic syndrome in Isfahan, Iran, 2024. A rationale and study protocol for randomized controlled trial

Metabolic syndrome (MetS) is the main general and clinical health challenge worldwide. Based on the National Cholesterol Education Program, if the person has three or more indices containing: elevated fasting blood sugar, high levels of triglycerides, hypertension, low levels of high-density lipoprotein cholesterol, and central obesity, he suffers MetS. The Mediterranean-Dietary Approaches to Stop Hypertension (DASH) Intervention for Neurodegenerative Delay diet is a novel diet that with the specific aim of safeguarding cognitive function. Propolis is a resinous substance produced by bees from the combination of buds and secretions of plants with saliva and bee enzymes. After propolis supplementation, a significant reduction in fasting plasma glucose levels and lipid profiles has been observed. Considering the importance of chronic diseases like MetS on health, the role of the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet and propolis supplement that will improve blood sugar, blood lipid, anthropometric indicators, blood pressure, and cognitive function, and limited contradictory studies, we decided to conduct this study. This study, which is a randomized controlled clinical trial study, will be conducted on adults with MetS who will visit Hazrat Ali Health Center in Isfahan. Participants must provide informed consent before engaging in the study. Demographic data such as age, gender, and medical history will be recorded. Then, anthropometric indices, MetS indices, and cognitive function will be measured in all subjects. The study participants will be divided into three groups and will be controlled for 12 weeks. We will have a MIND diet + placebo group, a MIND diet + propolis supplement group, and a control group that will receive a microcrystalline cellulose placebo and usual dietary advice. At the end of the intervention, all indices will be assessed again. The data obtained in the study will be analyzed at descriptive and analytical levels by the statistical software SPSS26. The present study's protocol was approved by the Iranian Registry of Clinical Trials (www.irct.ir) on 3/28/2023 and a registration reference is IRCT20230105057054N1.

Aggregation Behavior of Amyloid Beta Peptide Depends Upon the Membrane Lipid Composition

Protein aggregation plays a crucial role in the development of several neurodegenerative diseases. It is important to understand the aggregation process for the detection of the onset of these diseases. Alzheimer's Disease (AD) is one of the most prevalent neurodegenerative diseases caused by the aggregation of Aβ-40 and Aβ-42 peptides. The smaller oligomers lead to the formation of protein plaque at the neural membranes leading to memory loss and other disorders. Interestingly, aggregation takes place at the neural membranes, therefore the membrane composition seems to play an important role in the aggregation process. Despite a large number of literatures on the effect of lipid composition on protein aggregation, there are very few concise reviews that highlight the role of membrane composition in protein aggregation. In this review, we have discussed the implication of membrane composition on the aggregation of amyloid beta peptide with a special emphasis on cholesterol. We have further discussed the role of the degree of unsaturation of fatty acids and the participation of apolipoprotein E4 (ApoE4) in the onset of AD.

Metabolic Endotoxemia: From the Gut to Neurodegeneration

Metabolic endotoxemia is a severe health problem for residents in developed countries who follow a Western diet, disrupting intestinal microbiota and the whole organism's homeostasis. Although the effect of endotoxin on the human immune system is well known, its long-term impact on the human body, lasting many months or even years, is unknown. This is due to the difficulty of conducting in vitro and in vivo studies on the prolonged effect of endotoxin on the central nervous system. In this article, based on the available literature, we traced the path of endotoxin from the intestines to the blood through the intestinal epithelium and factors promoting the development of metabolic endotoxemia. The presence of endotoxin in the bloodstream and the inflammation it induces may contribute to lowering the blood-brain barrier, potentially allowing its penetration into the central nervous system; although, the theory is still controversial. Microglia, guarding the central nervous system, are the first line of defense and respond to endotoxin with activation, which may contribute to the development of neurodegenerative diseases. We traced the pro-inflammatory role of endotoxin in neurodegenerative diseases and its impact on the epigenetic regulation of microglial phenotypes.

Modulation of Gut Microbiota Through Dietary Intervention in Neuroinflammation and Alzheimer's and Parkinson's Diseases

PURPOSE OF REVIEW

The gut microbiota plays a crucial role in the pathogenesis of neuroinflammation and Alzheimer's and Parkinson's diseases. One of the main modulators of the gut microbiota is the diet, which directly influences host homeostasis and biological processes. Some dietary patterns can affect neurodegenerative diseases' progression through gut microbiota composition, gut permeability, and the synthesis and secretion of microbial-derived neurotrophic factors and neurotransmitters. This comprehensive review critically assesses existing studies investigating the impact of dietary interventions on the modulation of the microbiota in relation to neurodegenerative diseases and neuroinflammation.

RECENT FINDINGS

There are limited studies on the effects of specific diets, such as the ketogenic diet, Mediterranean diet, vegetarian diet, and Western diet, on the progression of neuroinflammation and Alzheimer's and Parkinson's diseases through the gut-brain axis. The ketogenic diet displays promising potential in ameliorating the clinical trajectory of mild cognitive impairment and Alzheimer's disease. However, conflicting outcomes were observed among various studies, highlighting the need to consider diverse types of ketogenic diets and their respective effects on clinical outcomes and gut microbiota composition. Vegetarian and Mediterranean diets, known for their anti-inflammatory properties, can be effective against Parkinson's disease, which is related to inflammation in the gut environment. On the other hand, the westernization of dietary patterns was associated with reduced gut microbial diversity and metabolites, which ultimately contributed to the development of neuroinflammation and cognitive impairment. Various studies examining the impact of dietary interventions on the gut-brain axis with regard to neuroinflammation and Alzheimer's and Parkinson's diseases are thoroughly reviewed in this article. A strong mechanistic explanation is required to fully understand the complex interactions between various dietary patterns, gut microbiota, and microbial metabolites and the effects these interactions have on cognitive function and the progression of these diseases.

Development of Malaysian-MIND diet scores for prediction of mild cognitive impairment among older adults in Malaysia

BACKGROUND

Mild Cognitive impairment (MCI) is a pre-demented state in the elderly populace. The Mediterranean & Dietary Approaches to Stop Hypertension (DASH) Intervention for Neurodegenerative Delay (MIND) diet has shown promise in reducing the risk of MCI and Alzheimer's disease in older people. Notably, the existing MIND diet is not adapted to the specific needs of older adults in Malaysia, considering distinct food cultures and availability. Consequently, this study aimed to develop the Malaysian version of the MIND diet (MY-MINDD) scores and investigate their association with MCI in the older adult populace of Malaysia.

METHODS

A comprehensive pooled data analysis was conducted on combined data from 810 participants sourced from the longitudinal Long-Term Research Grant Scheme-Towards Useful Aging (LRGS-TUA) and Fundamental Research Grant Scheme (FRGS) studies. The MY-MINDD scores were developed by incorporating existing MIND diet food groups, their corresponding scoring mechanisms, and consideration of common Malaysian foods which are proven to be beneficial and detrimental to cognitive function. To substantiate the MY-MINDD scoring system, its association with MCI was evaluated using a series of validated neuropsychological test batteries.

RESULTS

MY-MINDD consists of seven food groups promote brain health and four food groups exert negative cognitive outcomes. The study participants had an average age of 67.9 ± 4.7 years. The collective MY-MINDD score for all participants was 6.4 ± 0.1 (out of a maximum 11 points), revealing a lower score in individuals with MCI at 6.0 ± 1.7 compared to those without MCI at 6.6 ± 1.6 (p < 0.001). According to hierarchical multivariate binary logistic regression analysis, being in the highest tertile of MY-MINDD score was linked to reduced odds of MCI (odds ratio (OR) = 0.43, 95% confidence interval (CI): 0.26-0.72, p < 0.001) in the fully adjusted model in comparison to the lowest tertile.

CONCLUSION

The development of the MY-MINDD scores for Malaysian older population revealed that a stronger adherence to this diet is linked to a reduced risk of MCI. Further substantiation of the MY-MINDD scores using more objective measures, such as neuroimaging approaches and other neuropsychological batteries, is necessary.

Optimization of Naringenin-loaded nanoparticles for targeting of Vanin-1, iNOS, and MCP-1 signaling pathway in HFD-induced obesity

Naringenin, a natural dihydrochalcone flavonoid, exhibits diverse pharmacological properties. This study investigates the hypolipidemic effects of Nar-NPs on obese mice. The characteristics of Nar-NPs, including morphology, particle size, zeta potential, UV-vis, and FT-IR spectra, were examined. The anti-obesity properties of Nar-NPs were evaluated in obese rats, considering LD50, 1/20 LD50, and 1/50 LD50 for treatment preparation. Results indicated that synthesized Nar-NPs were uniform, spherical, and well-dispersed, with a size of 130.06 ± 1.98 nm and with a zeta potential of -25.6 ± 0.8 mV. Nar-NPs exhibited enhancement in the cumulative release of naringenin (56.87 ± 2.45 %) as compared to pure naringenin suspension 87.83 ± 1.84 % in 24 h of the study. The LD50 of Nar-NPs was determined as 412.5 mg/kg.b.w. HFD induced elevated glycemic, oxidative stress, and inflammatory biomarkers while reducing HDL-C, GSH, and superoxide dismutase (SOD) levels. Administration of Nar-NPs significantly mitigated body weight, glucose, insulin, leptin, TC, TG, SREBP1c, pAMPK, PPAR-α, as well as vanin-1, MCP-1, and iNOS mRNA gene expression. Histological investigations supported the biochemical and PCR findings. In a nutshell, the study suggests that the Nar-NPs could serve as a promising and viable pharmacological strategy for the treatment of obesity-related disorders.

High-Fat Diets in Animal Models of Alzheimer's Disease: How Can Eating Too Much Fat Increase Alzheimer's Disease Risk?

High dietary intake of saturated fatty acids is a suspected risk factor for neurodegenerative diseases, including Alzheimer's disease (AD). To decipher the causal link behind these associations, high-fat diets (HFD) have been repeatedly investigated in animal models. Preclinical studies allow full control over dietary composition, avoiding ethical concerns in clinical trials. The goal of the present article is to provide a narrative review of reports on HFD in animal models of AD. Eligibility criteria included mouse models of AD fed a HFD defined as > 35% of fat/weight and western diets containing > 1% cholesterol or > 15% sugar. MEDLINE and Embase databases were searched from 1946 to August 2022, and 32 preclinical studies were included in the review. HFD-induced obesity and metabolic disturbances such as insulin resistance and glucose intolerance have been replicated in most studies, but with methodological variability. Most studies have found an aggravating effect of HFD on brain Aβ pathology, whereas tau pathology has been much less studied, and results are more equivocal. While most reports show HFD-induced impairment on cognitive behavior, confounding factors may blur their interpretation. In summary, despite conflicting results, exposing rodents to diets highly enriched in saturated fat induces not only metabolic defects, but also cognitive impairment often accompanied by aggravated neuropathological markers, most notably Aβ burden. Although there are important variations between methods, particularly the lack of diet characterization, these studies collectively suggest that excessive intake of saturated fat should be avoided in order to lower the incidence of AD.

Mediation of the association between disadvantaged neighborhoods and cortical microstructure by body mass index

BACKGROUND

Living in a disadvantaged neighborhood is associated with worse health outcomes, including brain health, yet the underlying biological mechanisms are incompletely understood. We investigated the relationship between neighborhood disadvantage and cortical microstructure, assessed as the T1-weighted/T2-weighted ratio (T1w/T2w) on magnetic resonance imaging, and the potential mediating roles of body mass index (BMI) and stress, as well as the relationship between trans-fatty acid intake and cortical microstructure.

METHODS

Participants comprised 92 adults (27 men; 65 women) who underwent neuroimaging and provided residential address information. Neighborhood disadvantage was assessed as the 2020 California State area deprivation index (ADI). The T1w/T2w ratio was calculated at four cortical ribbon levels (deep, lower-middle, upper-middle, and superficial). Perceived stress and BMI were assessed as potential mediating factors. Dietary data was collected in 81 participants.

RESULTS

Here, we show that worse ADI is positively correlated with BMI (r = 0.27, p = .01) and perceived stress (r = 0.22, p = .04); decreased T1w/T2w ratio in middle/deep cortex in supramarginal, temporal, and primary motor regions (p < .001); and increased T1w/T2w ratio in superficial cortex in medial prefrontal and cingulate regions (p < .001). Increased BMI partially mediates the relationship between worse ADI and observed T1w/T2w ratio increases (p = .02). Further, trans-fatty acid intake (high in fried fast foods and obesogenic) is correlated with these T1w/T2w ratio increases (p = .03).

CONCLUSIONS

Obesogenic aspects of neighborhood disadvantage, including poor dietary quality, may disrupt information processing flexibility in regions involved in reward, emotion regulation, and cognition. These data further suggest ramifications of living in a disadvantaged neighborhood on brain health.

Palmitic Acid Modulates Microglial Cell Response to Metabolic Endotoxemia in an In Vitro Study

Metabolic endotoxemia (ME) is characterized by a 2-3-fold increase in blood endotoxin levels and low-grade systemic inflammation without apparent infection. ME is usually accompanied by metabolic syndrome, characterized by central obesity and hyperlipidemia. According to numerous studies, ME may lead to functional brain disorders, including cognitive decline, depression, and dementia. In the current in vitro study, we aimed to determine the direct and indirect impact of endotoxin (LPS) and palmitic acid (PA), representing saturated fatty acids, on the inflammatory and oxidative stress response in the human microglial HMC3 cells unstimulated and stimulated with IFNγ. The study's results revealed that direct HMC3 cell exposition to endotoxin and PA increased inflammatory response measured as levels of IL-6 and MCP-1 released into the medium and PGE2 levels in cell lysates. Moreover, direct HMC3 cell treatment with PA and LPS induced oxidative stress, i.e., ROS and COX-2 production and lipid peroxidation. On the contrary, an indirect effect of LPS and PA on microglial cells, assessed as the impact of macrophage metabolites, was much lower regarding the inflammatory response, although still associated with oxidative stress. Interestingly, IFNγ had a protective effect on microglial cells, reducing the production of pro-inflammatory mediators and oxidative stress in HMC3 cells treated directly and indirectly with LPS and PA.

The Effects of Body Composition, Physical Fitness on Time of Useful Consciousness in Hypobaric Hypoxia

INTRODUCTION

Several previous studies have reported that hypoxia accidents of fighter pilots are rarer than gravity-induced loss of consciousness and spatial disorientation; however, the risk is greater. Therefore, this study aimed to investigate the relationship between physical fitness and body composition on time of useful consciousness (TUC) in hypobaric hypoxia.

MATERIALS AND METHODS

Body composition and physical fitness testing on human participants were performed; subsequently, they were exposed to hypobaric hypoxia at a simulated altitude of 25,000 ft. Cognitive testing of the participants was accomplished by having them perform arithmetic task tables until they stopped writing for a period exceeding 5 seconds, at which point, they were placed on 100% oxygen. TUC was measured from the time the participants removed their oxygen masks to the time when the oxygen masks were placed back on them. Pearson's correlation was used to determine the relationship between TUC and other variables, and multiple regression was performed to determine the independent variables that best explain the TUC.

RESULTS

TUC was positively correlated with the maximum oxygen uptake, stroke volume, arteriovenous oxygen difference, and endurance (sit-up and push-up). The maximum heart rate on the ground, high altitude, body fat mass, and percent body fat were negatively correlated with TUC. A regression analysis showed that 84.5% of the TUC can be explained by body composition and physical fitness.

CONCLUSIONS

Our results revealed that increased cardiorespiratory fitness and decreased body fat mass could significantly impact the TUC. Therefore, for Air Force pilots who are frequently at high altitudes and at risk for exposure to hypoxia, aerobic exercise is significant to hypoxia tolerance.

Chronic cerebral hypoperfusion: a critical feature in unravelling the etiology of vascular cognitive impairment

Vascular cognitive impairment (VCI) describes a wide spectrum of cognitive deficits related to cerebrovascular diseases. Although the loss of blood flow to cortical regions critically involved in cognitive processes must feature as the main driver of VCI, the underlying mechanisms and interactions with related disease processes remain to be fully elucidated. Recent clinical studies of cerebral blood flow measurements have supported the role of chronic cerebral hypoperfusion (CCH) as a major driver of the vascular pathology and clinical manifestations of VCI. Here we review the pathophysiological mechanisms as well as neuropathological changes of CCH. Potential interventional strategies for VCI are also reviewed. A deeper understanding of how CCH can lead to accumulation of VCI-associated pathology could potentially pave the way for early detection and development of disease-modifying therapies, thus allowing preventive interventions instead of symptomatic treatments.

Impact of Diet and Exercise Interventions on Cognition and Brain Health in Older Adults: A Narrative Review

The ability to preserve cognitive function and protect brain structure from the effects of the aging process and neurodegenerative disease is the goal of non-pharmacologic, lifestyle interventions focused on brain health. This review examines, in turn, current diet and exercise intervention trends and the collective progress made toward understanding their impact on cognition and brain health. The diets covered in this review include the Mediterranean diet (MeDi), Dietary Approaches to Stop Hypertension (DASH), Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND), ketogenic diet, intermittent fasting, and weight loss management. The exercise approaches covered in this review include endurance, resistance, combined exercise programs, yoga, tai chi, and high-intensity interval training. Although valuable evidence is building concerning how diet and exercise influence cognitive performance and brain structure, many of the open questions in the field are concerned with why we see these effects. Therefore, more strategically designed intervention studies are needed to reveal the likely multiple mechanisms of action in humans.

MIND diet and cognitive function and its decline: A prospective study and meta-analysis of prospective cohort studies

BACKGROUND

Evidence on the association of the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet with cognitive aging is limited and inconsistent.

OBJECTIVE

We examined how the MIND diet is related to cognitive function and its decline among middle-aged and older adults.

METHODS

We included 4066 participants with baseline dietary assessment and at least one cognitive test from the China Health and Nutrition Survey (CHNS) in 1997, 2000, 2004, and 2006, with a median follow-up of 3 years. The modified MIND diet score (range: 0-12) was calculated based on nine healthy and three unhealthy food groups. Linear mixed-effect models were used to examine the association of adherence to the MIND diet with z-scores of cognitive function and cognitive decline. We also conducted a meta-analysis including our findings and seven other cohort studies.

RESULTS

At baseline, median MIND diet scores for the increasing tertile were 3.0, 4.0, and 5.5, respectively. Participants with higher MIND diet scores had significant better global cognitive function. The adjusted difference in global cognitive function z-score for every three-point increment of MIND diet scores was 0.11 (95% CI, 0.06, 0.16, p-trend<0.001), which was approximately equivalent to being one year younger in age. Consumption of nuts, fish, red meats, and tea showed independent positive associations with cognitive function, and fried food consumption exhibited negative associations. In the meta-analysis of 26,103 participants, one standardized deviation increment of the MIND score was associated with 0.042 (95 % CI 0.020, 0.065) units higher in global cognitive function z-score and 0.014 (95 % CI -0.010, 0.037) units slower in annual cognitive decline.

CONCLUSIONS

Our findings suggest that higher adherence to the MIND diet was associated with better cognitive function and potentially slower cognitive decline in later life. Further large-scale observational and interventional studies are warranted to elucidate the cognitive effects of the MIND diet.

PROSPERO REGISTRY NUMBER

This meta-analysis was registered at PROSPERO as CRD42022330417.

Associations between dietary fatty acid patterns and cognitive function in the Hispanic Community Health Study/Study of Latinos

Our objective was to quantify the cross-sectional associations between dietary fatty acid (DFA) patterns and cognitive function among Hispanic/Latino adults. This study included data from 8942 participants of the Hispanic Community Health Study/Study of Latinos, a population-based cohort study (weighted age 56·2 years and proportion female 55·2 %). The National Cancer Institute method was used to estimate dietary intake from two 24-h recalls. We derived DFA patterns using principal component analysis with twenty-six fatty acid and total plant and animal MUFA input variables. Global cognitive function was calculated as the average z-score of four neurocognitive tests. Survey linear regression models included multiple potential confounders such as age, sex, education, depressive symptoms, physical activity, energy intake and CVD. DFA patterns were characterised by the consumption of long-chain SFA, animal-based MUFA and trans-fatty acids (factor 1); short to medium-chain SFA (factor 2); very-long-chain n-3 PUFA (factor 3); very-long-chain SFA and plant-based MUFA and PUFA (factor 4). Factor 2 was associated with greater scores for global cognitive function (β = 0·037 (sd 0·012)) and the Digit Symbol Substitution (DSS) (β = 0·56 (sd 0·17)), Brief Spanish English Verbal Learning-Sum (B-SEVLT) (β = 0·23 (sd 0·11)) and B-SEVLT-Recall (β = 0·11 (sd 0·05)) tests (P < 0·05 for all). Factors 1 (β = 0·04 (sd 0·01)) and 4 (β = 0·70 (sd 0·18)) were associated with the DSS test (P < 0·05 for all). The consumption of short to medium-chain SFA may be associated with higher cognitive function among US-residing Hispanic/Latino adults. Prospective studies are necessary to confirm these findings.

Effectiveness of lifestyle medicine on cognitive functions in mild cognitive impairments and dementia: A systematic review on randomized controlled trials

Mild cognitive impairment (MCI) and dementia are associated with lifestyle risk factors, making lifestyle medicine a potentially viable intervention for people with MCI and dementia. The present study aims to examine the effectiveness of lifestyle medicine on cognitive functions among people with MCI and dementia, by performing a systematic review and meta-analysis on randomized controlled trials (RCT). A systematic literature search was conducted to extract RCTs adopting lifestyle interventions of diet, exercise, and stress management or emotional well-being. Results showed that 65 studies were eligible. Exercise was the most promising lifestyle intervention that improved various cognitive functions among people with MCI and dementia, and was more effective in MCI than in dementia. Interventions on stress management or emotional well-being did not show a significant effect on people with MCI, and the evidence for people with dementia was insufficient to conclude. Similarly, due to the lack of RCTs on a healthy dietary pattern, the effectiveness of diet interventions was not examined. In conclusion, the exercise component of lifestyle medicine can be an effective and clinically significant intervention for protecting people with MCI and dementia against cognitive declines, especially when served as an early intervention at the stage of MCI.

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.

Mediating role of obesity on the association between disadvantaged neighborhoods and intracortical myelination

We investigated the relationship between neighborhood disadvantage (area deprivation index [ADI]) and intracortical myelination (T1-weighted/T2-weighted ratio at deep to superficial cortical levels), and the potential mediating role of the body mass index (BMI) and perceived stress in 92 adults. Worse ADI was correlated with increased BMI and perceived stress (p's<.05). Non-rotated partial least squares analysis revealed associations between worse ADI and decreased myelination in middle/deep cortex in supramarginal, temporal, and primary motor regions and increased myelination in superficial cortex in medial prefrontal and cingulate regions (p<.001); thus, neighborhood disadvantage may influence the flexibility of information processing involved in reward, emotion regulation, and cognition. Structural equation modelling revealed increased BMI as partially mediating the relationship between worse ADI and observed myelination increases (p=.02). Further, trans-fatty acid intake was correlated with observed myelination increases (p=.03), suggesting the importance of dietary quality. These data further suggest ramifications of neighborhood disadvantage on brain health.

Lipids at the Nexus between Cerebrovascular Disease and Vascular Dementia: The Impact of HDL-Cholesterol and Ceramides

Cerebrovascular diseases and the subsequent brain hypoperfusion are at the basis of vascular dementia. Dyslipidemia, marked by an increase in circulating levels of triglycerides and LDL-cholesterol and a parallel decrease in HDL-cholesterol, in turn, is pivotal in promoting atherosclerosis which represents a common feature of cardiovascular and cerebrovascular diseases. In this regard, HDL-cholesterol has traditionally been considered as being protective from a cardiovascular and a cerebrovascular prospective. However, emerging evidence suggests that their quality and functionality play a more prominent role than their circulating levels in shaping cardiovascular health and possibly cognitive function. Furthermore, the quality of lipids embedded in circulating lipoproteins represents another key discriminant in modulating cardiovascular disease, with ceramides being proposed as a novel risk factor for atherosclerosis. This review highlights the role of HDL lipoprotein and ceramides in cerebrovascular diseases and the repercussion on vascular dementia. Additionally, the manuscript provides an up-to-date picture of the impact of saturated and omega-3 fatty acids on HDL circulating levels, functionality and ceramide metabolism.

MIND Dietary Pattern Adherence Is Selectively Associated with Cognitive Processing Speed in Middle-Aged Adults

BACKGROUND

Most previous work has focused on a single-nutrient, bottom-up approach when examining the influence of diet on neurocognition. Thus, the impact of dietary patterns on cognitive health is underinvestigated.

OBJECTIVES

We aimed to investigate the relation between different diet indices [i.e., Mediterranean, Dietary Approaches to Stop Hypertension (DASH), Healthy Eating Index-2015 (HEI-2015), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND)] and attentional inhibition and neuroelectric function.

METHODS

We undertook a cross-sectional analysis of adults aged 34.1 ± 6.0 y (n = 207, 116 females) with a BMI of 18.5 to >40 kg/m2 who completed the Dietary History Questionnaire II (DHQII) FFQ (Past Month and Year with Serving Sizes) to assess adherence to different diet quality indices. Attentional inhibition was assessed using a modified Eriksen flanker task during which event-related potentials (ERPs) were recorded. The amplitude and latency of the P3/P300 ERP were used to index attentional resource allocation and information processing speed, respectively.

RESULTS

P3 peak latency was inversely associated with greater adherence to the MIND dietary pattern during incongruent flanker trials (∆R2 = 0.02, β = -0.14, P = 0.043) but not during congruent trials. Adherence to the Mediterranean, DASH, and HEI-2015 patterns was not associated with P3 latency (P > 0.05). No associations were observed between the diet indices and attentional inhibition at the behavioral level (i.e., accuracy or reaction time) or P3 amplitude (all P values >0.05).

CONCLUSIONS

Greater adherence to the MIND diet was selectively associated with faster information processing speed in middle-aged adults with healthy to obese BMI. Further, the influence of the MIND diet for faster information processing speed might be particularly beneficial when cognitive control demands are increased. Future intervention trials testing the effects of consuming a MIND diet on cognitive function are warranted to help inform dietary recommendations for healthy cognitive aging.

Micro- and Macronutrient Intake and Food Group Frequency Consumed by Subjects with Cognitive Impairment and Dementia in Latin America: A Systematic Review

BACKGROUND

Nutrition has relevant role in the pathogenesis of dementia. However, in Latin American Countries (LAC), it is unknown which type of diet the subjects with dementia and cognitive dysfunction have.

OBJECTIVE

The main purpose of this study was to determine micro- and macronutrients and food frequency intake among the LAC population with mild cognitive impairment (MCI) and dementia.

METHODS

A systematic review using PubMed, Cochrane, Lilacs, and Scielo databases. Energy intake as well as micro- and macronutrients intake were analyzed using a random-effect model and presented in a forest plot.

RESULTS

Nine articles were included, an estimated energy intake of 1598.47 kcal (95% CI 1351.07-1845.88) was obtained. A daily consumption of 73.64 g/day (95% CI 64.07-83.2) of protein; 262.17 g/day (95% CI 214.51-309.93) of carbohydrates, and 57.91 g/day (95% CI 49.16-66.66) of fats were reported. A micronutrients daily intake consumption of 201.35μg/day of vitamin B9 (95% CI 125.32-277.38); 5.61μg/day of vitamin B12 (95% CI 2.53-8.70), and 139.67 mg/day of vitamin C (95% CI 59.33-220.02). Mineral intake of 637.32 mg/day of calcium (95% CI 288.54-986.11) and 9 mg/day of iron (95% CI 2.28-15.71) was obtained. A low intake of fruits and vegetables was found.

CONCLUSION

Individuals with MCI and dementia from LAC have a nutritional deficiency characterized by a lower intake of fruits and vegetables, a high consumption of carbohydrates and protein, adequate fats intake and vitamins B12, vitamin C, and iron consumption, but a low intake of vitamin B9 and calcium.

Age- and sex-specific modifiable risk factor profiles of dementia: evidence from the UK Biobank

Dementia constitutes a worldwide concern. To characterize the age- and sex-specific modifiable risk factor profiles of dementia, we included 497,401 UK Biobank participants (mean age = 56.5 years) without dementia at baseline (2006-2010) and followed them until March 2021. Cox proportional hazard models were used to estimate the age- and sex-specific hazard ratios (HRs) of incident dementia associated with socioeconomic (less education and high Townsend deprivation index), lifestyle (non-moderate alcohol intake, current smoking, suboptimal diet, physical inactivity, and unhealthy sleep duration), and health condition factors (hypertension, diabetes, cardiovascular diseases, and depressive symptoms). We also calculated the population attributable fractions (PAFs) of these factors. During follow-up (mean = 11.6 years), we identified 6564 dementia cases. HRs for the risk factors were similar between the sexes, while most factors showed stronger associations among younger participants. For example, the HRs of smoking were 1.74 (95% CI: 1.23, 2.47) for individuals aged < 50 years, and 1.18 (1.05, 1.33) for those aged ≥ 65 years. Overall, 46.8% (37.4%, 55.2%) of dementia cases were attributable to the investigated risk factors. The PAFs of the investigated risk factors also decreased with age, but that for health condition risk factors decreased with lower magnitude than socioeconomic and lifestyle risk factors. The stronger associations and greater PAFs of several modifiable risk factors for dementia among younger adults than older participants underscored the importance of dementia prevention from an earlier stage across the adult life course.

MIND Dietary Pattern and Its Association with Cognition and Incident Dementia in the UK Biobank

A high adherence to the Mediterranean-Dietary Approaches to Stop Hypertension Diet Intervention for Neurodegenerative Delay (MIND) has been associated with better cognition and a lower risk of dementia in some but not all studies. We measured adherence to MIND and its association with cognitive health in the UK Biobank (UKB). A MIND score was derived from 24 h diet recall questionnaires for 120,661 participants who completed at least one of seven self-administered cognitive function tests. In a subset of 78,663 participants aged 55+, diagnosis of dementia was determined by linked hospital and death records. Multivariable regression and Cox proportional hazard ratio (HR) models were used to examine associations of MIND with cognitive ability and incident dementia. Higher adherence to MIND was associated with a small but significant worsening in performance on five of seven cognitive tests (p < 0.002). Associations were strongest among highly educated participants (p < 0.002 for MIND × education interaction). After a mean follow-up time of 10.5 years, 842 participants developed dementia. Overall, MIND adherence was not associated with incident dementia. An inverse association was observed among females (HR = 0.87 per score standard deviation (SD), p = 0.008) but not males (HR = 1.09, p = 0.11) (p = 0.008 for MIND × sex interaction). Similar associations with cognitive ability and dementia were observed for the Alternative Healthy Eating Index-2010 (AHEI-2010) dietary pattern. Associations were not modified by genetic susceptibility. In UKB, the MIND diet was not associated with better cognitive test scores and only with lower dementia risk in women.

Ketogenic diets and Ketone suplementation: A strategy for therapeutic intervention

Ketogenic diets and orally administered exogenous ketone supplements are strategies to increase serum ketone bodies serving as an alternative energy fuel for high energy demanding tissues, such as the brain, muscles, and the heart. The ketogenic diet is a low-carbohydrate and fat-rich diet, whereas ketone supplements are usually supplied as esters or salts. Nutritional ketosis, defined as serum ketone concentrations of ≥ 0.5 mmol/L, has a fasting-like effect and results in all sorts of metabolic shifts and thereby enhancing the health status. In this review, we thus discuss the different interventions to reach nutritional ketosis, and summarize the effects on heart diseases, epilepsy, mitochondrial diseases, and neurodegenerative disorders. Interest in the proposed therapeutic benefits of nutritional ketosis has been growing the past recent years. The implication of this nutritional intervention is becoming more evident and has shown interesting potential. Mechanistic insights explaining the overall health effects of the ketogenic state, will lead to precision nutrition for the latter diseases.

Dementia Prevention in Clinical Practice

Over 55 million people globally are living with dementia and, by 2050, this number is projected to increase to 131 million. This poses immeasurable challenges for patients and their families and a significant threat to domestic and global economies. Given this public health crisis and disappointing results from disease-modifying trials, there has been a recent shift in focus toward primary and secondary prevention strategies. Approximately 40% of Alzheimer's disease (AD) cases, which is the most common form of dementia, may be prevented or at least delayed. Success of risk reduction studies through addressing modifiable risk factors, in addition to the failure of most drug trials, lends support for personalized multidomain interventions rather than a "one-size-fits-all" approach. Evolving evidence supports early intervention in at-risk patients using individualized interventions directed at modifiable risk factors. Comprehensive risk stratification can be informed by emerging principals of precision medicine, and include expanded clinical and family history, anthropometric measurements, blood biomarkers, neurocognitive evaluation, and genetic information. Risk stratification is key in differentiating subtypes of dementia and identifies targetable areas for intervention. This article reviews a clinical approach toward dementia risk stratification and evidence-based prevention strategies, with a primary focus on AD.

Dietary linoleic acid and the ratio of unsaturated to saturated fatty acids are inversely associated with significant liver fibrosis risk: A nationwide survey

Since no pharmaceuticals have been proven to effectively reduce liver fibrosis, dietary fatty acids may be beneficial as one of the non-pharmaceutical interventions due to their important roles in liver metabolism. In this cross-sectional study, we analyzed the data from the 2017–2018 cycle of National Health and Nutrition Examination Survey to examine the associations between the proportion and composition of dietary fatty acid intakes with significant liver fibrosis among US population. The dietary fatty acid consumptions were calculated based on two 24-h dietary recalls. Significant liver fibrosis was diagnosed based on liver stiffness measurement value derived from the vibration controlled transient elastography. Multivariate logistic regression analysis and sensitivity analysis were performed to assess the association between dietary fatty acid consumption and significant liver fibrosis risk. Finally, restricted cubic spline analysis was carried out to explore the dose–response between polyunsaturated fatty acids (PUFA) or linoleic acid intakes and the risk of significant liver fibrosis. The results showed that the multivariate adjusted odds ratios (95% confidence intervals) of significant liver fibrosis were 0.34 (0.14–0.84), 0.68 (0.50–0.91), and 0.64 (0.47–0.87) for the highest level of unsaturated to saturated fatty acid ratio, dietary PUFA, and linoleic acid intakes compared to the lowest reference, respectively. The sensitivity analysis and restricted cubic spline analysis produced similar results, reinforcing the inverse association of unsaturated to saturated fatty acid ratio, PUFA, and linoleic acid consumptions with significant liver fibrosis risk. However, other dietary fatty acids did not show the statistically significant association with significant liver fibrosis. In conclusion, dietary linoleic acid may play a key role in the inverse association between the unsaturated to saturated fatty acid ratio and the risk of significant liver fibrosis. Further studies are needed to confirm these findings.

Dissecting ultra-processed foods and drinks: Do they have a potential to impact the brain?

Ultra-processed foods and drinks (UPF) are formulation of ingredients, mostly of exclusive industrial use, that result from a series of industrial processes. They usually have a low nutrient but high energy density, with a high content of saturated and trans fats, and added sugars. In addition, they have characteristic organoleptic properties, and usually contain sophisticated additives, including artificial sweeteners, to intensify their sensory qualities and imitate the appearance of minimally processed foods. In addition, recent research has warned about the presence of chemicals (e.g., bisphenol) and neo-formed contaminants in these products. UPF production and consumption growth have been spectacular in the last decades, being specially consumed in children and adolescents. UPF features have been associated with a range of adverse health effects such as overeating, the promotion of inflammatory and oxidative stress processes, gut dysbiosis, and metabolic dysfunction including problems in glucose regulation. The evidence that these UPF-related adverse health effects may have on the neural network implicated in eating behavior are discussed, including the potential impact on serotonergic and dopaminergic neurotransmission, brain integrity and function. We end this review by placing UPF in the context of current food environments, by suggesting that an increased exposure to these products through different channels, such as marketing, may contribute to the automatic recruitment of the brain regions associated with food consumption and choice, with a detrimental effect on inhibitory-related prefrontal cortices. While further research is essential, preliminary evidence point to UPF consumption as a potential detrimental factor for brain health and eating behavior.

A healthy plant-based diet was associated with slower cognitive decline in African American older adults: a biracial community-based cohort

BACKGROUND

African American (AA) adults have about twice the risk of developing dementia compared with white adults. However, evidence on dietary modification in preventing cognitive decline from diverse populations focusing on AA adults is minimal.

OBJECTIVES

We aimed to evaluate the association between a plant-based diet and the rate of cognitive decline in a population-based sample of AA and white adults.

METHODS

This study consisted of 3337 participants from the Chicago Health and Aging Project (60% AA participants, 64% female). Plant-based diet quality was evaluated by the overall plant-based diet index (PDI), the healthful PDI (hPDI), and the unhealthful PDI (uPDI). Global cognition was assessed using a composite score of 4 individual tests of cognition. We used mixed models to examine the associations of PDI, hPDI, and uPDI with the rates of decline in global cognition, perceptual speed, and episodic memory. Models were adjusted for age, sex, presence of apoE e4 allele, lifestyle factors including education, cognitive activities, smoking status, calorie intake, risk factors for cardiovascular disease, time, and the interaction terms of time × each covariate.

RESULTS

AA and white participants had various dietary patterns. Higher hPDI was associated with a slower rate of decline in global cognition, perceptual speed, and episodic memory in AA participants but not white participants. AA study participants in the highest quintile of hPDI had significantly slower rates of global cognitive decline (β: 0.0183 ± 0.0086; P = 0.032), perceptual speed (β: 0.0179 ± 0.0088; P = 0.04), and episodic memory (β: 0.0163 ± 0.0118; P = 0.04) than individuals in the lowest quintile of hPDI. There were no associations of either PDI or uPDI with the rate of cognitive decline in either racial group.

CONCLUSIONS

A healthy plant-based diet was associated with a slower rate of decline in global cognition, perceptual speed, and episodic memory in AA adults.

Western and ketogenic diets in neurological disorders: can you tell the difference?

The prevalence of obesity tripled worldwide between 1975 and 2016, and it is projected that half of the US population will be overweight by 2030. The obesity pandemic is attributed, in part, to the increasing consumption of the high-fat, high-carbohydrate Western diet, which predisposes to the development of the metabolic syndrome and correlates with decreased cognitive performance. In contrast, the high-fat, low-carbohydrate ketogenic diet has potential therapeutic roles and has been used to manage intractable seizures since the early 1920s. The brain accounts for 25% of total body glucose metabolism and, as a result, is especially susceptible to changes in the types of nutrients consumed. Here, we discuss the principles of brain metabolism with a focus on the distinct effects of the Western and ketogenic diets on the progression of neurological diseases such as epilepsy, Parkinson's disease, Alzheimer's disease, and traumatic brain injury, highlighting the need to further explore the potential therapeutic effects of the ketogenic diet and the importance of standardizing dietary formulations to assure the reproducibility of clinical trials.

Lipid Metabolic Alterations in the ALS-FTD Spectrum of Disorders

There is an increasing interest in the study of the relation between alterations in systemic lipid metabolism and neurodegenerative disorders, in particular in Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD). In ALS these alterations are well described and evident not only with the progression of the disease but also years before diagnosis. Still, there are some discrepancies in findings relating to the causal nature of lipid metabolic alterations, partly due to the great clinical heterogeneity in ALS. ALS presentation is within a disorder spectrum with Frontotemporal Dementia (FTD), and many patients present mixed forms of ALS and FTD, thus increasing the variability. Lipid metabolic and other systemic metabolic alterations have not been well studied in FTD, or in ALS-FTD mixed forms, as has been in pure ALS. With the recent development in lipidomics and the integration with other -omics platforms, there is now emerging data that not only facilitates the identification of biomarkers but also enables understanding of the underlying pathological mechanisms. Here, we reviewed the recent literature to compile lipid metabolic alterations in ALS, FTD, and intermediate mixed forms, with a view to appraising key commonalities or differences within the spectrum.

Higher Dietary Intake of Advanced Glycation End Products Is Associated with Faster Cognitive Decline in Community-Dwelling Older Adults

OBJECTIVE

Dietary-derived advanced glycation end products (AGEs) vary for different food types and the methods employed during their preparation may contribute to diverse chronic health conditions. The goal of this study was to investigate the associations of dietary AGEs (dAGEs) with cognitive decline in older adults.

METHODS

Non-demented older adults (n = 684) underwent annual testing with 19 cognitive tests summarized as a global cognitive score based on five cognitive domains. We modified a previously validated food frequency questionnaire designed to assess dAGE. The modified questionnaire assessed portion size and frequency of consumption of six food groups (meat, poultry, fish, cheese, spreads, and processed foods), as well as the method of their preparation (e.g., grilling, boiling). dAGE was the sum of the scores of the six food groups. Linear mixed-effect models were used to examine the association of baseline dAGE with cognitive decline. All models controlled for age, sex, education, race, and body mass index (BMI).

RESULTS

Average follow-up was 3.0 years. Higher baseline dAGEs was associated with a faster rate of global cognitive decline (Estimate = -0.003 (standard error = 0.001, p-value = 0.015). This association was driven by declines in episodic memory (-0.004 (0.002, 0.013)) and perceptual speed (-0.003 (0.001, 0.049)) but not by semantic memory, working memory, and visuospatial domains. These associations were not attenuated by controlling for cardiovascular risk factors and diseases, including diabetes. Levels of dAGE of the specific food groups were not associated with cognitive decline.

CONCLUSIONS

Higher levels of dietary AGE levels in older adults are associated with faster cognitive decline. These data lend further support for the importance of diet and that its modification may slow or prevent late-life cognitive impairment. Further clinical studies will be needed and the molecular mechanisms underlying these associations will need to be identified.

Leg Fidgeting Improves Executive Function following Prolonged Sitting with a Typical Western Meal: A Randomized, Controlled Cross-Over Trial

Prolonged uninterrupted sitting and a typical Western meal, high in fat and refined sugar, can additively impair cognitive and cerebrovascular functions. However, it is unknown whether interrupting these behaviours, with a simple desk-based activity, can attenuate the impairment. The aim of this study was to determine whether regular leg fidgeting can off-set the detrimental effects of prolonged sitting following the consumption of a typical Western meal, on executive and cerebrovascular function. Using a randomized cross-over design, 13 healthy males consumed a Western meal and completed 180-min of prolonged sitting with leg fidgeting of 1 min on/4 min off (intervention [INT]) and without (control [CON]). Cognitive function was assessed pre and post sitting using the Trail Maker Test (TMT) parts A and B. Common carotid artery (CCA) blood flow, as an index of brain flow, was measured pre and post, and cerebral (FP1) perfusion was measured continuously. For TMT B the CON trial significantly increased (worsened) completion time (mean difference [MD] = 5.2 s, d = 0.38), the number of errors (MD = 3.33, d = 0.68) and cognitive fatigue (MD = 0.73, d = 0.92). Compared to CON, the INT trial significantly improved completion time (MD = 2.3 s, d = 0.97), and prevented declines in cognitive fatigue and a reduction in the number of errors. No significant changes in cerebral perfusion or CCA blood flow were found. Leg fidgeting for 1-min on/4-min off following a meal high in fats and refined sugars attenuated the impairment in executive function. This attenuation in executive function may not be caused by alterations in CCA blood flow or cerebral perfusion.

Efficacy and Safety of Ketone Supplementation or Ketogenic Diets for Alzheimer's Disease: A Mini Review

Alzheimer's disease (AD) is the most frequent age-related neurodegenerative disorder, with no curative treatment available so far. Alongside the brain deposition of β-amyloid peptide and hyperphosphorylated tau, neuroinflammation triggered by the innate immune response in the central nervous system, plays a central role in the pathogenesis of AD. Glucose usually represents the main fuel for the brain. Glucose metabolism has been related to neuroinflammation, but also with AD lesions. Hyperglycemia promotes oxidative stress and neurodegeneration. Insulinoresistance (e.g., in type 2 diabetes) or low IGF-1 levels are associated with increased β-amyloid production. However, in the absence of glucose, the brain may use another fuel: ketone bodies (KB) produced by oxidation of fatty acids. Over the last decade, ketogenic interventions i.e., ketogenic diets (KD) with very low carbohydrate intake or ketogenic supplementation (KS) based on medium-chain triglycerides (MCT) consumption, have been studied in AD animal models, as well as in AD patients. These interventional studies reported interesting clinical improvements in animals and decrease in neuroinflammation, β-amyloid and tau accumulation. In clinical studies, KS and KD were associated with better cognition, but also improved brain metabolism and AD biomarkers. This review summarizes the available evidence regarding KS/KD as therapeutic options for individuals with AD. We also discuss the current issues and potential adverse effects associated with these nutritional interventions. Finally, we propose an overview of ongoing and future registered trials in this promising field.

Macronutrient Intake and Risk of Dementia in Community-Dwelling Older Adults: A Nine-Year Follow-Up Cohort Study

BACKGROUND

Little is known about the association between macronutrient intake and incident dementia.

OBJECTIVE

To identify an optimal range of macronutrient intake associated with reduced risk of dementia.

METHODS

Our analysis included 93,389 adults aged 60-75 years from the UK Biobank. Diet was assessed using a web-based 24-h recall questionnaire between 2009-2012. Dementia was ascertained using hospital inpatient, death records, and self-reported data up to January 2021. We calculated a macronutrient score based on associations between an individual's macronutrient intake and incident dementia.

RESULTS

During a median follow-up of 8.7 years, 1,171 incident dementia cases were documented. We found U-shape relationships for carbohydrate, fat, and protein intake with incident dementia. Compared to individuals with optimal carbohydrate intake, those with high intake (HR (95%CI): 1.48(1.15-1.91)) but not low intake (1.19(0.89-1.57)) had a higher risk of dementia. In the multivariable analysis, a low-fat intake (HR (95%CI): 1.42(1.11-1.82)) was associated with a higher risk of all-cause dementia. After adjustment for covariates, a high (HR (95%CI): 1.41(1.09-1.83)) but not low protein intake (1.22(0.94-1.57)) was associated with an increased risk of dementia. Individuals in quintiles 3-5 of optimal macronutrient score had a lower risk of dementia compared with those in quintile 1 (HR (95%CI): 0.76(0.64-0.91) for quintile 3, 0.71(0.60-0.85) for quintile 4, 0.74(0.61-0.91) for quintile 5). The association between macronutrient score and incident dementia was significant across subgroups of age, gender, education, and smoking.

CONCLUSION

Moderate intakes of carbohydrate, fat, and protein were associated with the lowest risk of incident dementia.

Lipids in Pathophysiology and Development of the Membrane Lipid Therapy: New Bioactive Lipids

Membranes are mainly composed of a lipid bilayer and proteins, constituting a checkpoint for the entry and passage of signals and other molecules. Their composition can be modulated by diet, pathophysiological processes, and nutritional/pharmaceutical interventions. In addition to their use as an energy source, lipids have important structural and functional roles, e.g., fatty acyl moieties in phospholipids have distinct impacts on human health depending on their saturation, carbon length, and isometry. These and other membrane lipids have quite specific effects on the lipid bilayer structure, which regulates the interaction with signaling proteins. Alterations to lipids have been associated with important diseases, and, consequently, normalization of these alterations or regulatory interventions that control membrane lipid composition have therapeutic potential. This approach, termed membrane lipid therapy or membrane lipid replacement, has emerged as a novel technology platform for nutraceutical interventions and drug discovery. Several clinical trials and therapeutic products have validated this technology based on the understanding of membrane structure and function. The present review analyzes the molecular basis of this innovative approach, describing how membrane lipid composition and structure affects protein-lipid interactions, cell signaling, disease, and therapy (e.g., fatigue and cardiovascular, neurodegenerative, tumor, infectious diseases).

Elaidic acid induced NLRP3 inflammasome activation via ERS-MAPK signaling pathways in Kupffer cells

Trans fatty acids (TFA) in food can cause liver inflammation. Activation of NOD-like receptor protein-3 (NLRP3) inflammasome is a key factor in the regulation of inflammation. Accumulating evidence suggests that ERS-induced NLRP3 inflammasome activation underlies the pathological basis of various inflammatory diseases, but the precise mechanism has not been fully elucidated. Therefore, this paper focused on TFA, represented by elaidic acid (EA), to investigate the mechanism of liver inflammation. Levels of mRNA and protein were detected by RT-qPCR and Western blotting, the release of proinflammatory cytokines was measured by ELISA, and intracellular Ca²⁺ levels were determined by flow cytometer using Fluo 4-AM fluorescent probes. Our research indicated that EA induced the endoplasmic reticulum stress (ERS) response in Kupffer cells (KCs), accompanied by the activation of the mitogen-activated protein kinase (MAPK) signaling pathway, which resulted in NLRP3 inflammasome formation, and eventually increased the release of inflammatory factors. NLRP3 inflammasome activation was inhibited when KCs were pretreated with ERS inhibitors (4-PBA) and MAPK selective inhibitors. Furthermore, when ERS was blocked, the MAPK pathway was inhibited.

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.

Quercetin and its role in modulating endoplasmic reticulum stress: A review

The endoplasmic reticulum (ER) is the place where proteins and lipids are biosynthesized and where transmembrane proteins are folded. Both pathological and physiological situations may disturb the function of the ER, resulting in ER stress. Under stress conditions, the cells initiate a defensive procedure known as the unfolded protein response (UPR). Cases of severe stress lead to autophagy and/or the induction of cell apoptosis. Many studies implicate ER stress as a major factor contributing to many diseases. Therefore, the modulation of ER stress pathways has become an attractive therapeutic target. Quercetin is a plant-derived metabolite belonging to the flavonoids class which presents a range of beneficial effects including anti-inflammatory, cardioprotective, anti-oxidant, anti-obesity, anti-carcinogenic, anti-atherosclerotic, anti-diabetic, anti-hypercholesterolemic, and anti-apoptotic activities. Quercetin also has anti-cancer activity, and can be used as an adjuvant to decrease resistance to cancer chemotherapy. Furthermore, the effect of quercetin can be increased with the help of nanotechnology. This review discusses the role of quercetin in the modulation of ER stress (and related diseases) and provides novel evidence for the beneficial use of quercetin in therapy.

Higher circulating α-carotene was associated with better cognitive function: an evaluation among the MIND trial participants

There is emerging evidence linking fruit and vegetable consumption and cognitive function. However, studies focusing on the nutrients underlying this relationship are lacking. We aim to examine the association between plasma nutrients and cognition in a population at risk for cognitive decline with a suboptimal diet. The Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) trial is a randomized controlled intervention that examines the effects of the MIND diet to prevent cognitive decline. The primary outcome is global cognition. A multivariate linear model was used to investigate the association between blood nutrients and global and/or domain-specific cognition. The model was adjusted for age, sex, education, study site, smoking status, cognitive activities and physical activities. High plasma α-carotene was associated with better global cognition. Participants in the highest tertile of plasma α-carotene had a higher global cognition z score of 0⋅17 when compared with individuals in the lowest tertile (P 0⋅002). Circulating α-carotene levels were also associated with higher semantic memory scores (P for trend 0⋅007). Lutein and zeaxanthin (combined) was positively associated with higher semantic memory scores (P for trend 0⋅009). Our study demonstrated that higher α-carotene levels in blood were associated with higher global cognition scores in a US population at risk for cognitive decline. The higher α-carotene levels in blood reflected greater intakes of fruits, other types of vegetables and lesser intakes of butter and margarine and meat. The higher circulating levels of lutein plus zeaxanthin reflected a dietary pattern with high intakes of fruits, green leafy, other vegetables and cheese, and low consumption of fried foods. Objective nutrient markers in the blood can better characterize dietary intake, which may facilitate the implementation of a tailored dietary intervention for the prevention of cognitive decline.

Public knowledge of the influence of modifiable cardiovascular risk factors on dementia: a systematic literature review and meta-analysis

OBJECTIVES

This systematic review examined whether the general public are aware of the influence of modifiable cardiovascular risk factors (CVRFs) on dementia.

METHODS

Following PRISMA guidelines, five electronic databases (PubMed, Medline, CINAHL, ProQuest, and Scopus) were searched for studies published from 2009-2019, using the key terms "knowledge," "modifiable cardiovascular risk factors," and "dementia." Standardized critical appraisal instruments were used to evaluate the quality of the studies.

RESULTS

Of the 1,533 articles that were screened, 26 were included in this review. Modifiable CVRFs of dementia included behavioral factors (physical inactivity, poor dietary practices, high alcohol consumption, and heavy smoking) and medical conditions (hypertension, diabetes mellitus, hypercholesterolemia, and obesity). Although the association between CVRFs and dementia was identified (pooled prevalence is 24-50%), overall knowledge about this relationship in the general public was low. Sociodemographic variables, such as higher education, better economic status, and prior contact with a person with dementia, positively influenced dementia risk knowledge. Ethnic minorities showed good awareness of dementia risk from cardiovascular-related conditions.

CONCLUSION

Despite dementia is considered as a public health priority by World Health Organization, knowledge of the modifiable CVRFs and dementia is low in the general population. Public health policymakers should develop appropriate educational programs and interventions to equip the communities and vulnerable groups with this understanding so that they can be prepared to reduce dementia risk.

Fatty acids and beyond: Age and Alzheimer's disease related changes in lipids reveal the neuro-nutraceutical potential of lipids in cognition

Lipids are essential in maintaining brain function, and lipid profiles have been reported to be altered in aged and Alzheimer's disease (AD) brains as compared to healthy mature brains. Both age and AD share common metabolic hallmarks such as increased oxidative stress and perturbed metabolic function, and age remains the most strongly correlated risk factor for AD, a neurodegenerative disease. A major accompanying pathological symptom of these conditions is cognitive impairment, which is linked with changes in lipid metabolism. Thus, nutraceuticals that affect brain lipid metabolism or lipid levels as a whole have the potential to ameliorate cognitive decline. Lipid analyses and lipidomic studies reveal changes in specific lipid types with aging and AD, which can identify potential lipid-based nutraceuticals to restore the brain to a healthy lipid phenotype. The brain lipid profile can be influenced directly with dietary administration of lipids themselves, although because of synergistic effects of nutrients it may be more useful to consider a multi-component diet rather than single nutrient supplementation. Gut microbiota also serve as a source of beneficial lipids, and the value of treatments that manipulate the composition of gut microbiome should not be ignored. Lastly, instead of direct supplementation, compounds that affect pathways involved with lipid metabolism should also be considered as a way of manipulating lipid levels to improve cognition. In this review, we briefly discuss the role of lipids in the brain, the changing lipid profile in AD, current research on lipid-based nutraceuticals and their therapeutic potential to combat cognitive impairment.