Diet, cognition, and Alzheimer's disease: food for thought

Rationale and protocol of the LEAD 2.0 study: a randomized controlled trial assessing the feasibility of a virtually delivered 6-month exercise and nutrition intervention in older adults with subjective cognitive decline (SCD)

BACKGROUND

With growing prevalence of dementia worldwide, dementia risk reduction is a key interest of the World Health Organization's Global Dementia Action Plan. Subjective cognitive decline (SCD) is a prominent predictor of future dementia diagnosis. Therefore, people with SCD are an important group for dementia prevention intervention. Exercise and healthy diet are associated with a 30-60% decrease in dementia risk in longitudinal studies. Technological advances yield the potential of trials that deliver lifestyle interventions virtually, reaching people in a wide geographical spread. However, the feasibility of large-scale virtual trials still needs to be established.

OBJECTIVE

This trial aims to examine the feasibility of a factorial randomized controlled trial exploring a 6-month virtual, exercise and healthy diet intervention. Secondary objectives will examine whether feasibility outcomes vary by gender or technology access.

METHODS

We will recruit 140 older adults (65 + years) with SCD, who will receive a combination of Aerobic and Resistance Exercise (EX) or Stretching and Toning (STRETCH) and either Diet Counseling (DIET) or Brain Health Education (ED). Participants will be randomized to four weekly hours of one of four intervention arms: (1) EX and DIET; (2) EX and ED; (3) STRETCH and DIET; or (4) STRETCH and ED. EX will include moderate intensity aerobic and resistance training. DIET will instruct participants in brain healthy food choices. Assessments will be performed virtually at baseline, 6 months (post-intervention), and 12 months. Feasibility will be measured by recruitment rate, adherence, and retention.

DISCUSSION

Established feasibility will set the stage for a definitive trial. Feasibility results will also inform future virtual programs/services. In the long-term, if the interventions are feasible and beneficial, this intervention model could scale up and spread quickly to reach at-risk individuals for the purpose of dementia risk reduction.

TRIAL REGISTRATION

The Lifestyle, Exercise, and Diet (LEAD 2.0) study is registered with the US National Institutes of Health clinical trials registry (ClinicalTrials.gov identifier NCT06078748). This report complies with the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) statement.

Motoric cognitive risk syndrome: A review of fall risk assessment and management strategies

The aging global population is driving an increase in dementia, making the early identification of at-risk individuals crucial. Studies have shown that elderly people often exhibit a slowing gait before dementia diagnosis, which is linked to cognitive decline and predicts dementia risk. With 30% of those over 65 years of age experiencing falls annually, managing fall risk is essential. Motoric cognitive risk syndrome (MCR), characterized by subjective memory impairment and slow gait, is a pre-dementia condition that can identify high-risk individuals without extensive evaluation. The prevalence of MCR varies globally and is associated with an increased risk of falls, disability, and death. Early screening and intervention for MCR can delay dementia and improve fall regulation, offering a new perspective on elderly health management. This review synthesizes the current understanding of MCR-related falls, evaluates risk assessment methods, and discusses health strategies to provide a theoretical basis for fall prevention in community-dwelling older adults.

Isoflavone intake is associated with longitudinal changes in hippocampal volume, but not total grey matter volume, in Japanese middle-aged and older community dwellers

PURPOSE

This study aimed to clarify the associations between isoflavone intake and the volume changes of brain regions, specifically the hippocampus and total grey matter (TGM), over 10 years in Japanese middle-aged and older community dwellers.

METHODS

Data from the National Institute for Longevity Sciences-Longitudinal Study of Aging of 654 men and 671 women aged 40-85 years at baseline (6th wave survey, 2008-2010) who participated in the follow-up study (9th wave survey, 2018-2022) were analyzed. Total isoflavone intake was estimated based on a 3-day dietary record and categorized into quintile groups. The volumes of the hippocampus and TGM were measured by T1-weighted magnetic resonance imaging and longitudinal FreeSurfer software. Estimated mean brain volume changes by quintile of total isoflavone intake were assessed by a general linear model, with a stratified analysis by age group (< 65/≥65 years).

RESULTS

There were no significant associations between quintile of isoflavone intake and both brain volume changes over 10 years in all participants. On stratification by age group, the multivariable-adjusted difference over time and % change in hippocampal volume were more strongly associated with quintile of total isoflavone intake in those aged ≥ 65 years (difference over time: p for trend = 0.009; % change: p for trend = 0.012). There were no significant longitudinal associations between quintile of total isoflavone intake and TGM volume change in both age groups.

CONCLUSION

In older Japanese people aged ≥ 65 years, increased intake of total isoflavones might be a new nutritional strategy to prevent hippocampal atrophy.

A Comprehensive Review of the Antioxidant, Antimicrobial, and Therapeutic Efficacies of Black Cumin (Nigella sativa L.) Seed Oil and Its Thymoquinone

Black cumin (Nigella sativa L.) (family Ranunculaceae) is a largely utilized therapeutic herb worldwide. This comprehensive review discusses the pharmacological benefits of black cumin seed oil, focusing on its bioactive component thymoquinone (TQ). The review is structured as follows: First, we examine the antimicrobial properties of black cumin oil, followed by an analysis of its antioxidant capabilities. Finally, we explore its therapeutic potential, particularly in neurodegenerative diseases and COVID-19. Phytochemicals from N. sativa have exhibited potential for developing novel preventive and therapeutic strategies against jaundice, gastrointestinal disorders, skin diseases, anorexia, conjunctivitis, dyspepsia, intrinsic hemorrhage, amenorrhea, paralysis, anorexia, rheumatism, diabetes, hypertension, fever, influenza, eczema, asthma, cough, bronchitis, and headache. The broader spectrum of application for N. sativa and its essential bioactives have certainly enhanced the commercial value of this seed oil. TQ, a major constituent of black cumin seed oil, has numerous beneficial properties. Researchers have extensively studied black cumin seed oil and its major component, TQ. These studies have revealed a wide range of pharmacological properties, including anticancer, immunomodulatory, analgesic, antimicrobial, antidiabetic, and anti-inflammatory effects. Additionally, TQ has shown neuroprotective, spasmolytic, bronchodilatory, hepatoprotective, renoprotective, gastroprotective, and antioxidant activities.

Portulaca oleracea L. Methanolic Extract Protects the Brain of Male Rats Against Alzheimer's Disease

Alzheimer's disease (AD) occurs as a result of a chronic neurodegenerative disorder that is most frequently linked to a decline in cognitive function and memory. Twenty-four male rats were divided into four groups (n = 6); Group I was the negative control, Group II was the AlCl3-positive control, and Group III and Group IV were treated with 100 mg and 200 mg/kg of Portulaca oleracea methanolic extract, respectively. Aluminum chloride intoxication in Group II increased lipid peroxidation and decreased antioxidant parameters and affected interleukin-6 (IL-6), the tumor necrosis factor-alpha (TNF-α), acetylcholinesterase (AChE), and amyloid beta (Aβ), which lead to the induction of AD through injuring brain cells of AD rats. Treating the AD rats in Group III (GIII) and Group IV (GIV) with P. oleracea ameliorated the altered parameters in the AD rats. It also increased folic acid and vitamin B12 levels. P. oleracea modulated the physiological, biochemical, and histological changes brought on by AlCl3 intoxication in rats via oxidative stress and inflammatory pathways. The dose of P. oleracea in GIV successfully modified the behavioral changes brought on by AlCl3 in the AD rats more than that of GIII.

Multi-dimensional evidence from the UK Biobank shows the impact of diet and macronutrient intake on aging

BACKGROUND

The role of diet in aging is crucial, yet research findings on how specific diets influence human aging remain inconsistent. Understanding the relationship between dietary factors and aging could inform interventions to promote healthier aging outcomes.

METHODS

We analyzed data from the UK Biobank baseline survey and a 24-hour dietary assessment survey to investigate the association between diet and aging. The study examined 18 individual food intakes, 6 dietary patterns, 3 macronutrient intakes, and 3 dietary quality scores. High-dimensional Fixed Effects (HDFE) models were used to assess associations between dietary factors and aging measures, including telomere length, phenotypic age, and brain grey/white matter volumes. Multivariable Mendelian Randomization (MVMR) was employed to explore causal links between macronutrient consumption and aging outcomes.

RESULTS

Our results show that healthier diets are generally associated with improved aging outcomes from HDFE analyses. Plant-based food consumption correlates with increased telomere length and reduced phenotypic age, while animal-based food intake is linked to adverse aging effects. MVMR results confirm the causal benefits of carbohydrate intake, including reductions in phenotypic age (β = -0.0025; 95% CI = [-0.0047, -0.0003]; p = 0.0253) and increases in whole-brain grey matter volume (β = 0.0262; 95% CI = [0.007, 0.046]; p = 0.0087). The latter association remains significant after multiple testing correction.

CONCLUSIONS

This study underscores the significant role of diet in biological aging and provides robust evidence for the benefits of carbohydrate intake in promoting healthier aging. These findings highlight the potential of dietary interventions to improve aging-related outcomes.

Mediterranean diet related to 3-year incidence of cognitive decline: results from a cohort study in Chinese rural elders

OBJECTIVE

This study aims to examine the effect of the Mediterranean diet (MeDi) on cognitive decline among the Chinese elderly with a 3-year follow-up.

METHODS

This study is divided into two waves: wave-1 January 2019 to June 2019 (n = 2313); wave-2 January 2022 to March 2022 (n = 1648). MeDi scores were calculated from the Mediterranean Diet Adherence Screener (MEDAS), with the scoring of low compliance (0-6 points) and high compliance (7-14 points). The Mini-Mental State Examination (MMSE) was used to assess cognitive function. An MMSE score dropping ≥ 2 points from baseline was defined as cognitive decline. The relationships between MeDi score and cognitive decline were analyzed by linear regression models or Binary logistic regression.

RESULTS

During the 3-year follow-up, 23.8% of patients exhibited cognitive decline. The study revealed a significant difference in MMSE score changes between low and high MeDi adherence groups (p < 0.001). MeDi score was negatively correlated with cognitive deterioration (β = -0.020, p = 0.026). MeDi score was only negatively associated with cognitive decline in the female subgroup aged ≥65 years (β = -0.034, p = 0.033). The food beans (OR = 0.65, 95%CI:0.51, 0.84), fish (OR = 0.72, 95%CI:0.54, 0.97), and cooked vegetables (OR = 0.68, 95%CI:0.53, 0.84) were protective factors for cognitive decline.

CONCLUSIONS

This study suggests that greater adherence to the MeDi is linked to a reduced risk of cognitive decline in elderly people. However, this is found only in women who are 65 years old or older. It also found long-term adherence to beans, fish, and vegetables are more effective in improving cognitive function.

Exercise recovers weight gain, but not increased impulsive choice, caused by a high-fat diet

A high-fat diet has negative effects on physical, neurological, and behavioral outcomes. One consistent finding is that a diet high in fat increases impulsive choice behavior-behavior that is linked to a wide range of other negative health behaviors. While the mechanism for this increase in impulsive choice is not well understood, exercise, with its well-known and many benefits, may serve as an effective and accessible way to combat increased impulsive choice associated with a high-fat diet. The goal of this work was to test this possibility. Rats were divided into four groups in a two-by-two factorial design: exercise and control diet, sedentary and control diet, exercise and high-fat diet, sedentary and high-fat diet. Rats in the exercise groups engaged in 30-min of forced, moderate intensity wheel-running exercise five days per week. Rats in the high-fat diet groups ate a diet high in fat. Impulsive choice was measured using a delay discounting task. Exercise prevented weight gain associated with the high-fat diet. Exercise also preserved relative motivation for food reinforcement. However, exercise did not prevent increases in impulsive choice observed for rats that consumed a high-fat diet relative to the rats that consumed the control diet. This work rules out several possible mechanisms by which a high-fat diet may increase impulsive choice behavior. It makes clear that exercise alone may not stave off increases in impulsive choice caused by a high-fat diet. Future work is necessary to uncover the underlying mechanism for this effect and discover interventions, perhaps ones that combine both physically and cognitively demanding activities, to improve health and behavior as it relates to decision making processes.

The Role of Water-Soluble Vitamins and Vitamin D in Prevention and Treatment of Depression and Seasonal Affective Disorder in Adults

Depression is a major global health concern expected to worsen by 2030. In 2019, 28 million individuals were affected by depressive disorders. Dietary and supplemental vitamins show overall favorable preventative and therapeutic effects on depression. B vitamins are crucial for neurological function and mood regulation. Deficiencies in these vitamins are linked to depression. Studies on individual B vitamins show promise in improving depressive symptoms, particularly thiamin, riboflavin, niacin, and folate. Vitamin C deficiency may heighten depressive symptoms, but its exact role is not fully understood. Seasonal Affective Disorder (SAD) is associated with insufficient sunlight exposure and vitamin D deficiency. Vitamin D supplementation for SAD shows inconsistent results due to methodological variations. Further investigation is needed to understand the mechanisms of vitamins in depression treatment. Moreover, more research on SAD and light therapy's efficacy and underlying mechanisms involving photoreceptors, enzymes, and immune markers is needed. Although dietary and supplemental vitamins show overall favorable preventative and therapeutic effects on depression, dietitians treating psychiatric disorders face challenges due to diverse study designs, making direct comparisons difficult. Therefore, this article reviews the current literature to assess the role of dietary and supplemental vitamins in the prevention and treatment of depression. This review found that, although evidence supports the role of B vitamins and vitamins C and D in preventing and treating depression, further research is needed to clarify their mechanisms of action and determine the most effective intervention strategies.

An analysis of omega-3 clinical trials and a call for personalized supplementation for dementia prevention

INTRODUCTION

Targeted interventions are needed to delay or prevent the onset of neurodegenerative diseases. Poor dietary habits are associated with cognitive decline, highlighting the benefits of a healthy diet with fish and polyunsaturated fatty acids (PUFAs). Intake of omega-3 PUFAs docosahexaenoic acid (DHA), α-linolenic acid (ALA) and eicosapentaenoic acid (EPA) is linked with healthy aging, cardiovascular benefits, and reduced risk of Alzheimer's disease. Although omega-3 has health benefits, its intake is often inadequate and insufficient in modern diets. Although fish oil supplements offer an alternative source, inconsistent results from clinical trials raise questions about the factors determining their success.

AREAS COVERED

In this this review, the authors discuss the aforementioned determining factors and highlight strategies that could enhance the effectiveness of omega-3 PUFAs interventions for dementia and cognitive decline. Moreover, the authors provide suggestions for potential future research.

EXPERT OPINION

Factors such as diet, lifestyle, and genetic predisposition can all influence the effectiveness of omega-3 supplementation. When implementing clinical trials, it is crucial to consider these factors and recognize their potential impact on the interpretation of results. It is important to study each variable independently and the interactions between them.

The impact of diet quality on cognitive ability of Chinese older adults: evidence from the China Health and Nutrition Survey (CHNS)

BACKGROUND

Numerous studies have demonstrated a positive correlation between diet quality and cognitive performance, indicating that improving diet quality may be beneficial in preventing cognitive decline in older adults. However, few study has investigated the causal relationship between diet quality and cognitive performance. The purpose of this study is to evaluate the causal effects of diet quality on cognitive performance in Chinese adults aged 55 years and older. Particularly, we utilize the Chinese Diet Quality Index (CHEI), a dietary assessment tool tailored for Chinese populations, as a proxy for older adults' diet quality.

METHODS

Data were obtained from the China Health and Nutrition Survey (CHNS) ([Formula: see text], [Formula: see text]55 years old) conducted in 2004 and 2006. Cognitive function was tested by a subset of items from the Telephone Interview for Cognitive Status-Modified (TICS-m). Data on dietary intake was retrieved from three consecutive 24 hour recalls by participants and its quality was assessed by the 17-items Chinese Healthy Eating Index (CHEI). An Instrumental Variable technique was used to deal with the potential endogeneity of dietary quality. The instrumental variable used in our study is the community mean of CHEI.

RESULTS

After adjusting for socio-demographic factors (age, gender, education, per capita household income), lifestyle habits (smoking, alcohol consumption, physical activity, BMI), and chronic diseases (hypertension, diabetes), our findings revealed that improving diet quality had a significant positive effect on cognitive performance ([Formula: see text]), particularly in females aged 55-65 years ([Formula: see text]) and females with primary education and below ([Formula: see text]).

CONCLUSION

Our study suggests that improving diet quality and adhering to the Dietary Guidelines for Chinese may enhance cognitive performance in Chinese adults aged 55 years and older.

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.

An Optimal Dietary Pattern for Healthy Longevity: Scoping Differencing Review between the Mediterranean and the Japanese Diet

BACKGROUND

From the late 1980s to the early 1990s, micronutrients were associated with the concept of healthy aging and it was deemed as important to recognize eating lifestyles that better involved these healthy macronutrients.

METHODS

The present integrative differencing literature review aimed to identify correlations between healthy longevity and both the Mediterranean (MD) and the Japanese diet (JD).

RESULTS

A review of the primary and secondary literature was performed by consulting Embase and Medline (PubMed) databases. The bibliographic research focused on the critical reading of the studies in the last ten years. A total of 10 studies, 3 belonging to Embase and 7 to PubMed, were finally included, which exhaustively agreed with the inclusion criteria considered.

CONCLUSION

In all manuscripts selected, "over" elderly participants reported good adherence to both Mediterranean and Japanese eating behaviours, acceptable anthropometric characteristics, active social life, and regular physical activity.

Dietary consumption of beef and red meat: a scoping review and evidence map on cognitive outcomes across the lifespan

OBJECTIVE

Mixed evidence exists on the impact of beef consumption on cognition. The goal was to create an evidence map capturing studies assessing beef consumption and cognition to reveal gaps and opportunities in the body of literature.

DESIGN

A scoping review was conducted to locate studies up to March 2022 using PubMed and backwards citation screening. Data were extracted by two independent reviewers with conflict resolution, and a database was created and made publicly available.

SETTING

Intervention and observational studies.

PARTICIPANTS

Humans of any age, sex and/or health status, without moderate to severe cognitive impairment and/or abnormalities.

RESULTS

Twenty-two studies were identified that quantified beef or red meat intake and assessed cognition. Six studies assessed beef intake, with the remaining studies describing intake of red meat that may or may not include beef. Nine articles described randomised controlled trials (RCT), mostly conducted in children. Thirteen described observational studies, primarily conducted on adults and seniors. The most common cognitive domains measured included intelligence and general cognition, and memory. The majority of controlled studies were rated with high risk of bias, with the majority of observational trials rated with serious or greater risk of bias.

CONCLUSIONS

Red meat and beef intake and cognition is largely understudied. There is a significant lack of replication across study designs, populations, exposures and outcomes measured. The quality of the research would be considerably enhanced by focused assessments of beef intake (and not red meat in general) and specific cognitive domains, along with improved adherence to reporting standards.

[Beneficial effects of ketogenic diet for Alzheimer's disease management]

Alzheimer's disease (AD) is a neurodegenerative disease that affects almost 1 million people in France and 55 million in the world. This pathology is a global health preoccupation because of the lack of efficient curative treatment and the increase of its prevalence. During the last decade, the comprehension of pathophysiological mechanisms involved in AD have been improved. Amyloid plaques and neurofibrillary tangles accumulation are characteristic of Alzheimer's brain patients, accompanied by increased brain inflammation and oxidative stress, impaired cerebral metabolism of glucose and mitochondrial function. Treatment of AD includes different approaches, as pharmacology, psychology support, physiotherapy, and speech therapy. However, these interventions do not have a curative effect, but only compensatory on the disease. Ketogenic diet (KD), a low-carbohydrates and high-fat diet, associated with a medium-chain triglycerides intake (MCTs) might induce benefices for Alzheimer disease patients. Carbohydrate restriction and MCTs promotes the production of ketone bodies from fatty acid degradation. These metabolites replacing glucose, serve the brain as energetic substrates, and induce neuroprotective effects. Such a nutritional support might slow down the disease progression and improve cognitive abilities of patients. This review aims to examine the neuroprotective mechanisms of KD in AD progression and describes the advantages and limitations of KD as a therapeutic strategy.

Parkia from Cerrado: phytochemical bioprospection, toxicity and in vitro bioactivities of bark and flower extracts

Parkia platycephala is the only species of the genus Parkia that is endemic to the brazilian Cerrado and the tree symbol of the state of Tocantins, but there are still few studies regarding its bioprospecting. In this study, we aimed to investigate the phytochemical composition, toxicity and bioactivities of the bark and flower of Parkia platycephala. Hot sequential extractions (Soxhlet) were performed using methanol and hydroethanolic solution (70%), after degreasing the sample (hexane). The presence of flavonoids, tannins, steroids and alkaloids was detected in the preliminary screening. Trilinolein, (Z)-9-octadecenamide, 3-O-methyl-d-glucose were detected by Gas Chromatography coupled to Mass Spectrometry (GC-MS). In the Liquid Chromatography with Diode Array Detector (LC-PDA) analysis, it was detected exclusively ferulic acid (bark) and ellagic acid (flower). The ethanolic extract of the bark (IC50=10.69 ± 0.35 µgmL-1) has an antioxidant potential (DPPH• radical) higher than that of the rutin standard (IC50=15.85 ± 0.08 µgmL-1). All extracts showed excellent anticholinesterase potential (Ellman), with emphasis on the ethanol extract of the flower (IC50 =5.34 ± 0.12 µgmL-1). Regarding toxicity (Artemia salina), the methanolic extract of the bark and the ethanolic extract of the flower presented high and moderate levels, respectively. Such results limit the concentrations of biological activities in this study, however, the antioxidant and anticholinesterase indices fall short of toxicity. The results demonstrated promising antioxidant and anticholinesterase activities of both the bark and the flower of Parkia platycephala.

Bioactive Ingredients from Dairy-Based Lactic Acid Bacterial Fermentations for Functional Food Production and Their Health Effects

Lactic acid bacteria are traditionally applied in a variety of fermented food products, and they have the ability to produce a wide range of bioactive ingredients during fermentation, including vitamins, bacteriocins, bioactive peptides, and bioactive compounds. The bioactivity and health benefits associated with these ingredients have garnered interest in applications in the functional dairy market and have relevance both as components produced in situ and as functional additives. This review provides a brief description of the regulations regarding the functional food market in the European Union, as well as an overview of some of the functional dairy products currently available in the Irish and European markets. A better understanding of the production of these ingredients excreted by lactic acid bacteria can further drive the development and innovation of the continuously growing functional food market.

Potential Role for Diet in Mediating the Association of Olfactory Dysfunction and Cognitive Decline: A Nationally Representative Study

In the context of a growing body of evidence associating olfactory dysfunction (OD) with cognitive decline, this cross-sectional study used data from the 2013-2014 National Health and Nutrition Examination Survey (NHANES) sample in order to explore the role of dietary intake in this association. Leveraging a nationally representative sample of U.S. adults aged 60 years and older, this study analyzed dietary patterns using exploratory factor analysis. OD was categorized based on the NHANES Pocket Smell Test, and cognitive function was measured with a battery of tests. Survey-weighted multivariable regressions and causal mediation analysis were used to examine the relationship between dietary patterns, OD, and cognitive function. Results indicated that a poor adherence to a diet rich in monounsaturated fats (MUFAs) and polyunsaturated fats (PUFAs) was independently associated with both cognitive and olfactory dysfunctions, after adjusting for sociodemographic and health factors. Moreover, the relationship between OD and cognitive decline was found to be partly mediated by adherence to such a diet. This study proposes a potential link between diet, olfactory function, and cognitive decline, highlighting the role of nutritional interventions in mitigating cognitive decline, particularly in individuals with olfactory impairment.

Signalling cognition: the gut microbiota and hypothalamic-pituitary-adrenal axis

Cognitive function in humans depends on the complex and interplay between multiple body systems, including the hypothalamic-pituitary-adrenal (HPA) axis. The gut microbiota, which vastly outnumbers human cells and has a genetic potential that exceeds that of the human genome, plays a crucial role in this interplay. The microbiota-gut-brain (MGB) axis is a bidirectional signalling pathway that operates through neural, endocrine, immune, and metabolic pathways. One of the major neuroendocrine systems responding to stress is the HPA axis which produces glucocorticoids such as cortisol in humans and corticosterone in rodents. Appropriate concentrations of cortisol are essential for normal neurodevelopment and function, as well as cognitive processes such as learning and memory, and studies have shown that microbes modulate the HPA axis throughout life. Stress can significantly impact the MGB axis via the HPA axis and other pathways. Animal research has advanced our understanding of these mechanisms and pathways, leading to a paradigm shift in conceptual thinking about the influence of the microbiota on human health and disease. Preclinical and human trials are currently underway to determine how these animal models translate to humans. In this review article, we summarize the current knowledge of the relationship between the gut microbiota, HPA axis, and cognition, and provide an overview of the main findings and conclusions in this broad field.

Probiotics therapy show significant improvement in obesity and neurobehavioral disorders symptoms

Obesity is a complex metabolic disease, with cognitive impairment being an essential complication. Gut microbiota differs markedly between individuals with and without obesity. The microbial-gut-brain axis is an important pathway through which metabolic factors, such as obesity, affect the brain. Probiotics have been shown to alleviate symptoms associated with obesity and neurobehavioral disorders. In this review, we evaluated previously published studies on the effectiveness of probiotic interventions in reducing cognitive impairment, depression, and anxiety associated with obesity or a high-fat diet. Most of the probiotics studied have beneficial health effects on obesity-induced cognitive impairment and anxiety. They positively affect immune regulation, the hypothalamic-pituitary-adrenal axis, hippocampal function, intestinal mucosa protection, and glucolipid metabolism regulation. Probiotics can influence changes in the composition of the gut microbiota and the ratio between various flora. However, probiotics should be used with caution, particularly in healthy individuals. Future research should further explore the mechanisms underlying the gut-brain axis, obesity, and cognitive function while overcoming the significant variation in study design and high risk of bias in the current evidence.

Dietary diversity and risk of late-life disabling dementia in middle-aged and older adults

BACKGROUND & AIMS

A balanced diet integrating several foods and nutrients may promote the maintenance of brain function. Previous studies have substantiated the above hypothesis in the regional population in Japan. This study aimed to investigate the potential effect of dietary diversity on the risk of disabling dementia in a nationwide large-scale cohort of the Japanese population.

METHODS

A total of 38,797 participants (17,708 men and 21,089 women) aged 45-74 years were followed up for a median of 11.0 years. The daily frequencies of the consumption of each of the 133 food and beverage items listed on a food frequency questionnaire (excluding five alcoholic beverages) were measured. The dietary diversity score was calculated as the number of food items consumed per day. Multivariable adjusted Cox proportional hazards regression models were used to calculate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) of the dietary diversity score quintile groups.

RESULTS

We documented 4302 participants with disabling dementia (11.1%) during the follow-up period. Among women, the dietary diversity score was inversely associated with disabling dementia (highest quintile HR [with the lowest quintile as the reference]: 0.67; 95% CI: 0.56-0.78; Q1-Q5 p for trend <0.001), but this was not true among men (highest quintile HR: 1.06; 95% CI: 0.87-1.29; Q1-Q5 p for trend = 0.415). These results did not change substantially when using disabling dementia with stroke as the outcome; the association remained significant among women but was absent among men.

CONCLUSIONS

Our findings indicate that eating a variety of foods may prevent disabling dementia only among women. Thus, the habit of consuming a variety of food items has important public health implications for women.

Methyl Donors, Epigenetic Alterations, and Brain Health: Understanding the Connection

Methyl donors such as choline, betaine, folic acid, methionine, and vitamins B6 and B12 are critical players in the one-carbon metabolism and have neuroprotective functions. The one-carbon metabolism comprises a series of interconnected chemical pathways that are important for normal cellular functions. Among these pathways are those of the methionine and folate cycles, which contribute to the formation of S-adenosylmethionine (SAM). SAM is the universal methyl donor of methylation reactions such as histone and DNA methylation, two epigenetic mechanisms that regulate gene expression and play roles in human health and disease. Epigenetic mechanisms have been considered a bridge between the effects of environmental factors, such as nutrition, and phenotype. Studies in human and animal models have indicated the importance of the optimal levels of methyl donors on brain health and behavior across the lifespan. Imbalances in the levels of these micronutrients during critical periods of brain development have been linked to epigenetic alterations in the expression of genes that regulate normal brain function. We present studies that support the link between imbalances in the levels of methyl donors, epigenetic alterations, and stress-related disorders. Appropriate levels of these micronutrients should then be monitored at all stages of development for a healthier brain.

Eat for better cognition in older adults at risk for Alzheimer's disease

Alzheimer's disease is a worldwide public health problem. However, the treatment method and treatment effects are limited. The stages of preclinical Alzheimer's disease are thought to be a better intervention period. Thus, in this review, food is given focus and the intervention stage put forward. We summarized the role of diet, nutrient supplementation, and microbioecologics in cognitive decline and found that interventions such as modified Mediterranean-ketogenic diet, nuts, vitamin B, and Bifidobacterium breve A1 are beneficial to cognition protection. Eating, rather than just taking medicine, is suggested to be an effective treatment method for older adults at risk for Alzheimer's disease.

Diet, nutrition, and cognitive function: A narrative review of Japanese longitudinal studies

In aging societies, the number of older people with cognitive decline and dementia is increasing. Proper nutrition is a key factor that can help in the prevention of these age-related impairments. This narrative review of longitudinal studies in Japan outlines the relationship between nutrition and the brain and focuses on Japanese nutritional epidemiologic studies. The results of Japanese cohort studies suggest that rather than a single food or nutrient, a nutritionally balanced diet that integrates a variety of foods and nutrients can contribute to the maintenance of brain function and be effective in preventing dementia. In addition, this review considers a nutritional approach to reducing the severity of cognitive decline in individuals with mild cognitive impairment and dementia, and suggests lifelong strategies for the prevention of cognitive decline. It is important that we consider the practice of eating not only as a way to obtain nutrients, but also as an important lifestyle habit to maintain our physical and mental health. Geriatr Gerontol Int 2022; 22: 825-831.

The effect of dietary patterns on mild cognitive impairment and dementia incidence among community-dwelling older adults

Multiple studies have shown that dietary patterns have beneficial health effects on cognitive function. However, information on this relationship is presently limited, particularly among older adults. Thus, this study aimed to determine the effects of dietary patterns on mild cognitive impairment (MCI) and dementia incidence among Malaysian community-dwelling older adults. In this prospective cohort study, a total of 280 participants aged 60 years and above were included in the 5-year follow-up analysis. Participants' sociodemographic, medical history, anthropometry, blood pressure, body composition, biochemical indices, cognitive assessments, psychosocial functions, functional status, and dietary intake were obtained. MCI was classified based on Petersen criteria, whereas dementia status was assessed using clinical dementia rating (CDR). Univariate analysis was performed for all variables, followed by multinomial regression analysis to identify the ability of dietary patterns in predicting the incidence of MCI and dementia. After controlling for confounding factors, the findings indicated that "local snacks-fish and seafood-high salt foods" dietary pattern was associated with an increased risk of MCI incidence, where the T3 [adjusted OR = 3.943 (95% CI: 1.212-12.832), p = 0.032] had the highest OR compared to T2 [adjusted OR = 3.252 (95% CI: 1.108-9.546), p = 0.023]. Meanwhile, a negative association across the tertiles of tropical fruits-oats dietary pattern and dementia incidence was observed [T2: adjusted OR = 0.152 (95% CI: 0.026-0.871), p = 0.034; T3: Adjusted OR = 0.101 (95% CI: 0.011-0.967), p = 0.047]. In conclusion, specific dietary patterns, particularly "local snacks-fish and seafoods-high salt foods," were shown to increase the risk of MCI, while increasing intakes of "tropical fruits-oats" dietary patterns would protect against the dementia incidence among Malaysian older adults.

The role of mixed B vitamin intakes on cognitive performance: Modeling, genes and miRNAs involved

OBJECTIVE

To assess the relationships between mixed B vitamin intakes (B1, B2, B3, B6, B9, B12) and cognitive performance, as well as their molecular mechanisms.

METHODS

The associations of mixed B vitamin intakes with cognitive function were assessed using multivariate regression models, weighted quantile sum (WQS), quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR). GeneMANIA, Comparative Toxicogenomics Database, MIENTURNET, miRNAsong were employed as the main data-mining methods.

RESULTS

Overall effects of the B vitamin intake mixture were significantly associated with global cognition in the WQS, qgcomp, and BKMR models. A mixture of B vitamins (B1, B2, B3, B9) interacted with the five genes (IL1B, BCL2, CASP3, BAX, PTGS2) and was associated with better cognitive function, especially CASP3 and BAX. Physical interactions (77.6%) were observed to be the most important interactions in gene networks. The IL-18 signaling pathway, apoptosis, and Alzheimer's disease were annotated as the key molecular mechanisms involved in mixed B vitamins' improving cognitive function. NFKB1, ATF3, and NR3C1 were the key significant transcription factors associated with cognitive function targeted by a mixture of B vitamins. The strong interaction and expression of hsa-miR-34a-5p, hsa-miR-128-3p, hsa-miR-181a-5p, and hsa-miR-204-5p are involved in mixed B vitamins' better cognitive performance. We also created and evaluated miRNA sponge sequences for these miRNAs, which might be used to alleviate cognitive decline. The cutoff thresholds for B vitamin intake levels that are associated with cognition performance were reported.

CONCLUSIONS

Given the increased incidence of dementia across the world, increasing daily mixed B vitamin intake via regular meals may contribute to minimizing dementia risk. Further studies are warranted to identify these links in well-characterized cohorts of diverse populations, either independently or together.

Basic lifestyle habits and volume change in total gray matter among community dwelling middle-aged and older Japanese adults

The brain controls human behavior, and the gray matter is the main resource of neuronal cells. We examined the longitudinal relationship between six basic lifestyle habits (diet, exercise, sleep, alcohol consumption, smoking, and social activity including employment) and total gray matter volume in community-dwelling adults in Japan. This two-year follow-up study with data derived from the National Institute for Longevity Sciences, Longitudinal Study of Aging, Aichi, Japan, included adults aged 40-87 years (n = 1665, men: 51%). Lifestyle habits were assessed at baseline (2008-2010) using self-reported questionnaires and three-day dietary records. Total gray matter volume at baseline and after two years was estimated using T1-weighted brain magnetic resonance imaging and FreeSurfer software. The association between each lifestyle factor, the total number of healthy lifestyle habits, and gray matter volume change was determined via a multiple linear regression analysis adjusting for baseline age, total gray matter volume, and other confounders. The mean ± standard deviation decrease in total gray matter volume during the two-year follow-up period was 0.94 ± 1.86% in men and 0.61 ± 2.27% in women. In the multiple regression analysis, volume loss in total gray matter positively correlated with male smoking, while it was negatively correlated with male social activity and employment, female dietary diversity, and the total number of healthy lifestyle habits (standardized beta coefficient; -0.061 in men [p = 0.07], -0.113 in women [p < 0.05]). Therefore, engaging in social activities, non-smoking, a diverse diet, or adopting one healthy lifestyle habit may help prevent gray matter volume loss.

Plants, Plants, and More Plants: Plant-Derived Nutrients and Their Protective Roles in Cognitive Function, Alzheimer’s Disease, and Other Dementias

Background and Objectives: Alzheimer’s disease (AD) is the most common form of dementia, with the risk of developing it attributed to non-modifiable and modifiable factors. Currently, there is no cure for AD. A plant-based diet may protect against cognitive decline, due to the effects of plant-based nutrients such as vitamins, antioxidants, and fiber. The aim of the review is to summarize current literature on plant-based nutrients and their impact on cognition. Materials and Methods: A search was conducted on PubMed for clinical and murine studies, using combinations of the following words: “Alzheimer’s disease”, “dementia”, “cognition”, “plant-based diet”, “mild cognitive impairment”, “vitamin B”, “vitamin C”, “vitamin E, “beta carotene”, “antioxidants”, “fiber”, “vitamin K”, “Mediterranean diet”, “vitamin D”, and “mushrooms”. Results and Conclusions: A diet rich in vitamin B and antioxidants can benefit the cognitive functions of individuals as shown in randomized clinical trials. Vitamin K is associated with improved cognition, although large randomized controlled trials need to be done. Fiber has been shown to prevent cognitive decline in animal studies. Vitamin D may contribute to cognitive health via anti-inflammatory processes. Several medical organizations have recommended a plant-based diet for optimizing cognitive health and potentially helping to prevent dementia.

Effect of macular pigment carotenoids on cognitive functions: A systematic review

Lutein and zeaxanthin-xanthophyll carotenoids with antioxidant and anti-inflammatory characteristics-are present in the retina and the brain. High concentrations of these carotenoids have been positively related to cognitive performance. Therefore, this systematic review analyses the relationship between macular pigment density and cognitive functions. Most relevant databases were scoured for studies on healthy people relating cognitive functions to macular pigment optical density (MPOD). There were no age, sex, or race limitations. PROSPERO registration: CRD42021254833. Nineteen studies were included, seven randomized controlled trials (RCT) and eleven observational studies. The general aim of the studies was to examine the association between carotenoids (lutein, meso‑zeaxanthin and zeaxanthin) and cognitive function. Most observational studies correlates MPOD levels with cognitive function or brain activity. Besides, RCTs compared the cognitive function and/or brain activity after increasing lutein and zeaxanthin intake though dietary supplementation or avocado consumption. Dietary lutein and zeaxanthin intake increased MPOD in six of the seven clinical trials and significantly improved most of the cognitive functions studied. A wide variety of test and methodologies for measuring cognitive functions were observed. Memory, processing speed, attention and reasoning were the cognitive function significantly related to MPOD levels in adults. Brain activity also was related to MPOD, but the results were inconsistent. Only four of the eleven observational studies were based on young people and all studies showed a significant relationship between MPOD and cognitive functions. This systematic review showed a direct relationship among cognitive functions, macular pigment and the intake of lutein and zeaxanthin.

Current and Near-Future Treatment of Alzheimer's Disease

Recent findings have improved our understanding of the multifactorial nature of AD. While in early asymptomatic stages of AD, increased amyloid-β synthesis and tau hyperphosphorylation play a key role, while in the latter stages of the disease, numerous dysfunctions of homeostatic mechanisms in neurons, glial cells, and cerebrovascular endothelium determine the rate of progression of clinical symptoms. The main driving forces of advanced neurodegeneration include increased inflammatory reactions in neurons and glial cells, oxidative stress, deficiencies in neurotrophic growth and regenerative capacity of neurons, brain insulin resistance with disturbed metabolism in neurons, or reduction of the activity of the Wnt-β catenin pathway, which should integrate the homeostatic mechanisms of brain tissue. In order to more effectively inhibit the progress of neurodegeneration, combination therapies consisting of drugs that rectify several above-mentioned dysfunctions should be used. It should be noted that many widely-used drugs from various pharmacological groups, "in addition" to the main therapeutic indications, have a beneficial effect on neurodegeneration and may be introduced into clinical practice in combination therapy of AD. There is hope that complex treatment will effectively inhibit the progression of AD and turn it into a slowly progressing chronic disease. Moreover, as the mechanisms of bidirectional communication between the brain and microbiota are better understood, it is expected that these pathways will be harnessed to provide novel methods to enhance health and treat AD.

Soybean Meal Extract Preserves Memory Ability by Increasing Presynaptic Function and Modulating Gut Microbiota in Rats

Age-related degenerative brain diseases frequently manifest as memory deficits. Dietary interventions or nutraceuticals may provide efficacious treatments through prevention and cure. Soybean meal, a byproduct of soy oil refining, has health benefits, but its effect on memory function is unknown. Therefore, we evaluated the effect of the oral administration of soybean meal extract (SME) for 2 weeks on memory function using the Morris water maze (MWM) test in healthy rats and investigated the possible underlying mechanisms. First, analysis of the composition revealed that SME is rich in isoflavones; SME did not exhibit hepatotoxicity or renal toxicity at the different doses tested. The MWM results revealed that the escape latency and movement distance of rats were significantly shorter in the SME group than in the control group, indicating that SME can help in memory preservation. In addition, SME increased the levels of presynaptic proteins such as synaptophysin, synaptobrevin, synaptotagmin, syntaxin, synapsin I, and 25-kDa synaptosome-associated protein as well as protein kinases and their phosphorylated expression, including extracellular signal-regulated kinases 1 and 2 (ERK1/2), protein kinase C (PKC), and Ca2+/calmodulin-dependent protein kinase II (CaMKII) in the hippocampal nerve terminals (synaptosomes). Transmission electron microscopy also indicated that SME increased the number of synaptic vesicles in hippocampal synaptosomes. Furthermore, SME rats exhibited altered microbiota composition compared with control rats. Therefore, our data suggest that SME can increase presynaptic function and modulate gut microbiota, thus aiding in memory preservation in rats.

Feasibility and preliminary efficacy of the LEAD trial: a cluster randomized controlled lifestyle intervention to improve hippocampal volume in older adults at-risk for dementia

BACKGROUND

Healthy diet and exercise are associated with reduced risk of dementia in older adults. The impact of diet and exercise interventions on brain health is less consistent, especially with dietary interventions which rely on varying approaches. Our objective was to evaluate the feasibility and preliminary efficacy of a 6-month intervention combining exercise with a novel dietary counseling approach to improve hippocampal volume among older adults at-risk for dementia.

METHODS

Participants with vascular risk factors and subjective cognitive decline or early mild cognitive impairment were cluster randomized in groups of 3-4 to the diet intervention (DIET) or control education (ED) group. All participants engaged in 1 h of supervised exercise per week and additional exercise at home. DIET involved 1 h per week of group-based dietary counseling comprising education, goal setting, and strategy training. ED involved 1 h per week of group-based brain health education classes. Our primary outcome was change in hippocampal volume from baseline to 6 months. Secondary outcomes included changes in cognitive function, blood biomarkers, diet, and fitness. Recruitment challenges and early discontinuation of the trial due to COVID-19 necessitated a revised focus on feasibility and preliminary efficacy.

RESULTS

Of 190 older adults contacted, 14 (7%) were eligible and enrolled, constituting 21% of our recruitment target. All participants completed the intervention and attended 90% of exercise and DIET/ED sessions on average. All 6-month assessments prior to COVID-19 were completed but disruptions to in-person testing resulted in incomplete data collection. No serious adverse events occurred and all participants expressed positive feedback about the study. Preliminary findings did not identify any significant changes in hippocampal volume; however, substantial improvements in diet and HbA1c were observed with DIET compared to ED (d = 1.75 and 1.07, respectively).

CONCLUSIONS

High adherence and retention rates were observed among participants and preliminary findings illustrate improvements in diet quality and HbA1c. These results indicate that a larger trial is feasible if difficulties surrounding recruitment can be mitigated.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03056508 .

One-Carbon Metabolism: Pulling the Strings behind Aging and Neurodegeneration

One-carbon metabolism (OCM) is a network of biochemical reactions delivering one-carbon units to various biosynthetic pathways. The folate cycle and methionine cycle are the two key modules of this network that regulate purine and thymidine synthesis, amino acid homeostasis, and epigenetic mechanisms. Intersection with the transsulfuration pathway supports glutathione production and regulation of the cellular redox state. Dietary intake of micronutrients, such as folates and amino acids, directly contributes to OCM, thereby adapting the cellular metabolic state to environmental inputs. The contribution of OCM to cellular proliferation during development and in adult proliferative tissues is well established. Nevertheless, accumulating evidence reveals the pivotal role of OCM in cellular homeostasis of non-proliferative tissues and in coordination of signaling cascades that regulate energy homeostasis and longevity. In this review, we summarize the current knowledge on OCM and related pathways and discuss how this metabolic network may impact longevity and neurodegeneration across species.

Pursuit of precision medicine: Systems biology approaches in Alzheimer's disease mouse models

Alzheimer's disease (AD) is a complex disease that is mediated by numerous factors and manifests in various forms. A systems biology approach to studying AD involves analyses of various body systems, biological scales, environmental elements, and clinical outcomes to understand the genotype to phenotype relationship that potentially drives AD development. Currently, there are many research investigations probing how modifiable and nonmodifiable factors impact AD symptom presentation. This review specifically focuses on how imaging modalities can be integrated into systems biology approaches using model mouse populations to link brain level functional and structural changes to disease onset and progression. Combining imaging and omics data promotes the classification of AD into subtypes and paves the way for precision medicine solutions to prevent and treat AD.

Greek High Phenolic Early Harvest Extra Virgin Olive Oil Reduces the Over-Excitation of Information-Flow Based on Dominant Coupling Mode (DoCM) Model in Patients with Mild Cognitive Impairment: An EEG Resting-State Validation Approach

BACKGROUND

Extra virgin olive oil (EVOO) constitutes a natural compound with high protection over cognitive function that could positively alter brain dynamics and the mixture of within and between-frequency connectivity.

OBJECTIVE

The balance of cross-frequency coupling over within-frequency coupling can build a nonlinearity index (NI) that encapsulates the over-excitation of information flow between brain areas and across experimental time. The present study investigated for the very first time how the Greek High Phenolic Early Harvest Extra Virgin Olive Oil (HP-EH-EVOO) versus Moderate Phenolic (MP-EVOO) and Mediterranean Diet (MeDi) intervention in people with mild cognitive impairment (MCI) could affect their spontaneous EEG dynamic connectivity.

METHODS

Forty-three subjects (14 in MeDi, 16 in MP-EVOO, and 13 in HP-EH-EVOO) followed an EEG resting-state recording session (eyes-open and closed) before and after the treatment. Following our dominant coupling mode model, we built a dynamic integrated dynamic functional connectivity graph that tabulates the functional strength and the dominant coupling mode model of every pair of brain areas.

RESULTS

Signal spectrum within 1-13 Hz and theta/beta ratio have decreased in the HP-EH-EVOO group in the eyes-open condition. The intervention improved the FIDoCM across groups and conditions but was more prominent in the HP-EH-EVOO group (p < 0.001). Finally, we revealed a significant higher post-intervention reduction of NI (ΔNITotal and α) for the HP-EH-EVOO compared to the MP-EVOO and MeDi groups (p < 0.0001).

CONCLUSION

Long-term intervention with HP-EH-EVOO reduced the over-excitation of information flow in spontaneous brain activity and altered the signal spectrum of EEG rhythms.

Nutrition Challenges of Patients with Alzheimer's Disease and Related Dementias: A Qualitative Study from the Perspective of Caretakers in a Mental National Referral Hospital

PURPOSE

The burden of Alzheimer's dementia greatly impacts patients and their immediate families. Studies on the perspective of caretakers regarding nutrition in patients with Alzheimer's disease (AD) dementia are lacking. Yet this information is needed to guide clinical care for patients with dementia. The study explored caretakers' perspective on nutritional challenges faced by patients with Alzheimer's disease and related Dementias at Butabika National Referral Hospital.

METHODS

We conducted 20 in-depth interviews and 2 focus group discussions with 20 health workers and 16 caregivers, respectively. The focus group discussions and in-depth interviews were audio-recorded and transcribed. Analysis was conducted using a thematic, constant comparative approach with an emphasis on dominant themes.

RESULTS

Participants had a mean age of 37 in the range (27-44) years. Seventeen (47%) of them were males. Their duration of Care for Dementia to patients was in the range (2-7) years. The highest level of education was a bachelor's degree and the primary level was the lowest. Thirteen (35%) were married and twenty-three (65%) were not, and they either survived on salaries or wages as a source of income. The key emerging issues were 1) hindrances to nutritional care in dementia, 2). Factors leading to inadequate nutrition among people with dementia and 3). Recommendations to improve nutrition needs.

CONCLUSION

Caretakers experience challenges ranging from psychotic manifestations of a patient to hindrances in the provision of nutritional care. A better understanding of their experience is essential for the development of interventions to help the family members, health workers and other care takers promote good nutrition in patients with Alzheimer's dementia. A clear referral system should be established to prevent overcrowding of patients at a mental national referral hospital to ensure adequate timely nutritional support to those admitted. Capacity building programs should continue to address the knowledge gap in nutritional requirements of patients with Alzheimer's dementia.

A Randomized Clinical Trial of Greek High Phenolic Early Harvest Extra Virgin Olive Oil in Mild Cognitive Impairment: The MICOIL Pilot Study

BACKGROUND

Extra virgin olive oil (EVOO) constitutes a natural compound with high protection over cognitive function.

OBJECTIVE

To investigate for the first time the effect of Greek High Phenolic Early Harvest Extra Virgin Olive Oil (HP-EH-EVOO) versus Moderate Phenolic (MP-EVOO) and Mediterranean Diet (MeDi) in people with mild cognitive impairment (MCI).

METHODS

We conducted a randomized prospective study so as to examine the HP-EH-EVOO and MP-EVOO versus MeDi in MCI. Genetic predisposition (APOEɛ4) to Alzheimer's disease (AD) was tested and an extensive neuropsychological battery was administered at baseline and after 12 months. Each participant was randomized and assigned one of three groups: 1) Group 1 received the HP-EH-EVOO (50 mL/day); 2) Group 2 received the MP-EVOO (50 mL/day), and 3) Group 3 received only the MeDi instructions.

RESULTS

Better follow-up performance was found in Group 1 compared to Group 2 and Group 3 in the almost all cognitive domains. Moreover, Group 2 showed also significant improvement compared to Group 3 in ADAS-cog (p = 0.001) and MMSE (p = 0.05), whereas Group 3 exhibited worse or similar to baseline performance in almost all domains. In particular, Group 1 and Group 2 had better outcomes with regards to ADAS-cog (p = 0.003), Digit Span (p = 0.006), and Letter fluency (p = 0.003). Moreover, there was a significant difference (p = 0.001) in the presence of APOEɛ4 between the Groups 1 and 2 versus Group 3.

CONCLUSION

Long-term intervention with HP-EH-EVOO or MP-EVOO was associated with significant improvement in cognitive function compared to MeDi, independent of the presence of APOEɛ4.

The Association Between Folate and Alzheimer's Disease: A Systematic Review and Meta-Analysis

Alzheimer's disease (AD) is the most common type of neurodegenerative disease leading to dementia in the elderly. Increasing evidence indicates that folate plays an important role in the pathogenesis of AD. To investigate the role of folate deficiency/possible deficiency in the risk of AD and the benefical effect of sufficient folate intake on the prevention of AD, a systematic review and meta-analysis were performed. The Web of Science, PubMed, CENTRAL, EBSCO, CNKI, CQVIP, and Wanfang databases were searched. The analysis of cross-sectional studies showed that the standardized mean difference (SMD) was −0.60 (95% confidence interval (CI): −0.65, −0.55), indicating that plasma/serum folate level is lower in AD patients than that in controls. Moreover, the combined odds ratio (OR) of case-control studies was 0.96 (95% CI: 0.93, 0.99), while the combined ORs were 0.86 (95% CI: 0.46, 1.26) and 1.94 (95% CI: 1.02, 2.86) in populations with normal levels of folate (≥13.5 nmol/L) and folate deficiency/possible deficiency (<13.5 nmol/L), respectively. In addition, the risk ratio (RR) of the cohort studies was 1.88 (95% CI: 1.20, 2.57) in populations with folate deficiency/possible deficiency. Furthermore, when the intake of folate was equal to or higher than the recommended daily allowance, the combined RR and hazard ratio (HR) were 0.44 (95% CI: 0.18, 0.71) and 0.76 (95% CI: 0.52, 0.99), respectively. These results indicate that folate deficiency/possible deficiency increases the risk for AD, while sufficient intake of folate is a protective factor against AD.

Diet Quality and Cognitive Performance in Australian Adults Aged 55-85 Years: A Cross-Sectional Analysis of the Hunter Community Study Cohort

There is a lack of evidence to determine if diet quality is associated with cognitive performance in older adults. Therefore, the aim of this study was to examine whether diet quality is associated with cognitive performance among older adults. A cross-sectional, secondary analysis of baseline data from the Hunter Community Study (HCS), comparing diet quality, measured using the Australian Recommended Food Score (ARFS), along with validated cognitive performance instruments the Audio Recorded Cognitive Screen (ARCS) and the Mini-Mental State Examination (MMSE) were undertaken in adults aged 55–85 years, living in Newcastle, NSW, Australia. Adjusted linear regression analyses showed that, compared with the lowest ARFS quintile, those in the highest quintile had an ARCS score 5.883 units greater (p < 0.001; R² = 0.0098). Furthermore, when quintiles of ARFS score were tested against each ARCS sub-scale score, statistically significant associations were observed with the greatest effect for the Memory (β = 4.055; p = 0.001; R² = 0.0065) and Attention (β = 4.136; p = 0.002; R² = 0.0047) domains. No statistically significant associations were observed between quintiles of ARFS and MMSE score in the adjusted linear regression analyses. In conclusion, a positive association was observed between diet quality and cognitive performance within this sample of older Australian adults. Further investigation of the above association over time, when follow-up data becomes available, in longitudinal analysis is recommended.

Dietary patterns are related to cognitive functioning in elderly enriched with individuals at increased risk for Alzheimer's disease

PURPOSE

To investigate cross-sectional associations between dietary patterns and cognitive functioning in elderly free of dementia.

METHODS

Data of 389 participants from the German DELCODE study (52% female, 69 ± 6 years, mean Mini Mental State Score 29 ± 1) were included. The sample was enriched with elderly at increased risk for Alzheimer's disease (AD) by including participants with subjective cognitive decline, mild cognitive impairment (MCI) and siblings of AD patients. Mediterranean and MIND diets were derived from 148 Food Frequency Questionnaire items, and data-driven patterns by principal component analysis (PCA) of 39 food groups. Associations between dietary patterns and five cognitive domain scores were analyzed with linear regression analyses adjusted for demographics (model 1), and additionally for energy intake, BMI, other lifestyle variables and APOe4-status (model 2). For PCA-derived dietary components, final model 3 included all other dietary components.

RESULTS

In fully adjusted models, adherence to Mediterranean and MIND diet was associated with better memory. The 'alcoholic beverages' PCA component was positively associated with most cognitive domains. Exclusion of MCI subjects (n = 60) revealed that Mediterranean and MIND diet were also related to language functions; associations with the alcoholic beverages component were attenuated, but most remained significant.

CONCLUSION

In line with data from elderly population samples, Mediterranean and MIND diet and some data-derived dietary patterns were related to memory and language function. Longitudinal data are needed to draw conclusions on the putative effect of nutrition on the rate of cognitive decline, and on the potential of dietary interventions in groups at increased risk for AD.

Treatment-Resistant Depression Revisited: A Glimmer of Hope

Major Depressive Disorder (MDD) is a highly prevalent psychiatric disorder worldwide. It causes individual suffering, loss of productivity, increased health care costs and high suicide risk. Current pharmacologic interventions fail to produce at least partial response to approximately one third of these patients, and remission is obtained in approximately 30% of patients. This is known as Treatment-Resistant Depression (TRD). The burden of TRD exponentially increases the longer it persists, with a higher risk of impaired functional and social functioning, vast losses in quality of life and significant risk of somatic morbidity and suicidality. Different approaches have been suggested and utilized, but the results have not been encouraging. In this review article, we present new approaches to identify and correct potential causes of TRD, thereby reducing its prevalence and with it the overall burden of this disease entity. We will address potential contributory factors to TRD, most of which can be investigated in many laboratories as routine tests. We discuss endocrinological aberrations, notably, hypothalamic-pituitary-adrenal (HPA) axis dysregulation and thyroid and gonadal dysfunction. We address the role of Vitamin D in contributing to depression. Pharmacogenomic testing is being increasingly used to determine Single Nucleotide Polymorphisms in Cytochrome P450, Serotonin Transporter, COMT, folic acid conversion (MTHFR). As the role of immune system dysregulation is being recognized as potentially a major contributory factor to TRD, the measurement of C-reactive protein (CRP) and select immune biomarkers, where testing is available, can guide combination treatments with anti-inflammatory agents (e.g., selective COX-2 inhibitors) reversing treatment resistance. We focus on established and emerging test procedures, potential biomarkers and non-biologic assessments and interventions to apply personalized medicine to effectively manage treatment resistance in general and TRD specifically.

Eight different bioactivity profiles of 40 cinnamons by multi-imaging planar chromatography hyphenated with effect-directed assays and high-resolution mass spectrometry

Spices contain plenty of bioactive compounds, used to valorize foods. However, product quality may be affected by contaminations and adulterations along the global production chain. A newly developed multi-imaging in combination with bioactivity screening directly pointed to individual multi-potent compounds. For cinnamon as prominent example, the multi-imaging results provided a wealth of new information on their effects and clearly visualized the valorizing potential of cinnamon to foods. The separation focus was in the mid-polar to apolar range. Eight effect-directed assays (EDA, i.e. one radical scavenging, two biological and five biochemical assays) were performed in situ the high-performance thin-layer chromatography (HPTLC) adsorbent. Several multi-potent compound zones were revealed and further characterized by high-resolution mass spectrometry (HRMS), highlighting the bioactive potential of cinnamaldehyde, cinnamic acid, benzoic acid, coumarin, linoleic acid, oleic acid, stearic acid, palmitic acid, caproic acid, and linalool oxide. This HPTLC-UV/Vis/FLD-EDA-HRMS profiling provided comprehensive information on product quality and safety.

Role of nutraceuticals in cognition during aging and related disorders

Cognitive abilities are compromised with advancing age posing a great risk for the development of dementia and other related brain disorders. Genetic susceptibility as well as environmental exposures determine the fate of cognitive aging and its transition to pathological states. Emerging epidemiological and observational studies have revealed the importance of lifestyle factors including dietary patterns and nutritional intake in the maintenance of cognitive health and reducing the risk of neurodegenerative disorders. In this context, nutraceutical interventions have gained considerable attention in preventing age-related cognitive deficits and counteracting pathological processes. Nutraceuticals include dietary plants and derivatives, food supplements and processed foods with nutritional and pharmaceutical values. The present review highlights the importance of nutraceuticals in attenuating cognitive aging and its progression to dementia, with specific emphasis on chemical constituents, neurocognitive properties and mechanism of action.

Dietary Pattern, Gut Microbiota, and Alzheimer's Disease

Alzheimer's disease is the most common neurodegenerative disease. Until now, there has been no specific medicine that can cure Alzheimer's disease or effectively reverse the disease process. A good dietary pattern is an efficient way to prevent or delay the progression of the disease. Evidence suggests that diet may affect β-amyloid production and tau processing or may regulate inflammation, metabolism, and oxidative stress associated with Alzheimer's disease, which can be exerted by gut microbiota. The gut microbiota is a complex microbial community that affects not only various digestive diseases but also neurodegenerative diseases. Studies have shown that gut microbial metabolites, such as pro-inflammatory factors, short-chain fatty acids, and neurotransmitters, can affect the pathogenesis of Alzheimer's disease. Clinical studies suggested that the gut microbial composition of patients with Alzheimer's disease is different, in particular to lower abundances of Eubacterium rectale and Bacteroides fragilis, which have an anti-inflammatory activity. The purpose of this review is to summarize the neuropathological pathogenesis of Alzheimer's disease, and the modulation of dietary patterns rather than single dietary components on Alzheimer's disease through the gut-brain axis was discussed.

Behavioral, neuromorphological, and neurobiochemical effects induced by omega-3 fatty acids following basal forebrain cholinergic depletion in aged mice

Background

In recent years, mechanistic, epidemiologic, and interventional studies have indicated beneficial effects of omega-3 polyunsaturated fatty acids (n-3 PUFA) against brain aging and age-related cognitive decline, with the most consistent effects against Alzheimer’s disease (AD) confined especially in the early or prodromal stages of the pathology.

In the present study, we investigated the action of n-3 PUFA supplementation on behavioral performances and hippocampal neurogenesis, volume, and astrogliosis in aged mice subjected to a selective depletion of basal forebrain cholinergic neurons. Such a lesion represents a valuable model to mimic one of the most reliable hallmarks of early AD neuropathology.

Methods

Aged mice first underwent mu-p75-saporin immunotoxin intraventricular lesions to obtain a massive cholinergic depletion and then were orally supplemented with n-3 PUFA or olive oil (as isocaloric control) for 8 weeks. Four weeks after the beginning of the dietary supplementation, anxiety levels as well as mnesic, social, and depressive-like behaviors were evaluated. Subsequently, hippocampal morphological and biochemical analyses and n-3 PUFA brain quantification were carried out.

Results

The n-3 PUFA treatment regulated the anxiety alterations and reverted the novelty recognition memory impairment induced by the cholinergic depletion in aged mice. Moreover, n-3 PUFA preserved hippocampal volume, enhanced neurogenesis in the dentate gyrus, and reduced astrogliosis in the hippocampus. Brain levels of n-3 PUFA were positively related to mnesic abilities.

Conclusions

The demonstration that n-3 PUFA are able to counteract behavioral deficits and hippocampal neurodegeneration in cholinergically depleted aged mice promotes their use as a low-cost, safe nutraceutical tool to improve life quality at old age, even in the presence of first stages of AD.

Self-Selection Bias: An Essential Design Consideration for Nutrition Trials in Healthy Populations

Many researchers have identified the issue of self-selection bias hindering the ability to detect nutrient effects in healthy populations. However, it appears that no effort has been made to mitigate this potential design flaw. By recruiting individuals on the basis of pre-trial dietary intake, the Memory and Attention Supplementation Trial aimed to capture a cohort of participants with a wide variety of dietary intake, thus increasing the likelihood of a diverse range of nutrient status. This perspective specifically examines the profile of these trial volunteers and in doing so, we present the first empirical evidence of self-selection bias when recruiting healthy volunteers for a randomized controlled trial of a nutrient-based supplement. These findings support the anecdotal proposal that traditional recruitment methods inherently attract trial volunteers who are vastly unrepresentative of the population and threatens the generalizability of this field of research. Alternative approaches to recruitment, including a-priori screening for baseline diet quality and nutrient status, are discussed as essential design recommendations to ensure accurate interpretation of nutrient effects within the context of baseline participant characteristics.

Mens Sana in Corpore Sano: Does the Glycemic Index Have a Role to Play?

Although diet interventions are mostly related to metabolic disorders, nowadays they are used in a wide variety of pathologies. From diabetes and obesity to cardiovascular diseases, to cancer or neurological disorders and stroke, nutritional recommendations are applied to almost all diseases. Among such disorders, metabolic disturbances and brain function and/or diseases have recently been shown to be linked. Indeed, numerous neurological functions are often associated with perturbations of whole-body energy homeostasis. In this regard, specific diets are used in various neurological conditions, such as epilepsy, stroke, or seizure recovery. In addition, Alzheimer’s disease and Autism Spectrum Disorders are also considered to be putatively improved by diet interventions. Glycemic index diets are a novel developed indicator expected to anticipate the changes in blood glucose induced by specific foods and how they can affect various physiological functions. Several results have provided indications of the efficiency of low-glycemic index diets in weight management and insulin sensitivity, but also cognitive function, epilepsy treatment, stroke, and neurodegenerative diseases. Overall, studies involving the glycemic index can provide new insights into the relationship between energy homeostasis regulation and brain function or related disorders. Therefore, in this review, we will summarize the main evidence on glycemic index involvement in brain mechanisms of energy homeostasis regulation.