Intake of Seven Essential Amino Acids Improves Cognitive Function and Psychological and Social Function in Middle-Aged and Older Adults: A Double-Blind, Randomized, Placebo-Controlled Trial

Functional analysis of feedback inhibition-insensitive aspartate kinase identified in a threonine-accumulating mutant of Saccharomyces cerevisiae

Humans and mammals need to ingest essential amino acids (EAAs) for protein synthesis. In addition to their importance as nutrients, EAAs are involved in brain homeostasis. However, elderly people are unable to efficiently consume EAAs from their daily diet due to reduced appetite and variations in the contents of EAAs in foods. On the other hand, strains of the yeast Saccharomyces cerevisiae that accumulate EAAs would enable elderly people to intakegest adequate amounts of EAAs and thus might slow down the neurodegenerative process, contributing to the extension of their healthy lifespan. In this study, we isolated a mutant (strain HNV-5) that accumulates threonine, an EAA, derived from a diploid laboratory yeast by conventional mutagenesis. Strain HNV-5 carries a novel mutation in the HOM3 gene encoding the Ala462Thr variant of aspartate kinase (AK). Enzymatic analysis revealed that the Ala462Thr substitution significantly decreased the sensitivity of AK activity to threonine feedback inhibition even in the presence of 50 mM threonine. Interestingly, Ala462Thr substitution did not affect the catalytic ability of Hom3, in contrast to previously reported amino acid substitutions that resulted in reduced sensitivity to threonine feedback inhibition. Furthermore, yeast cells expressing the Ala462Thr variant showed an approximately threefold increase in intracellular threonine content compared to that of the wild-type Hom3. These findings will be useful for the development of threonine-accumulating yeast strains that may improve the quality of life in elderly people.IMPORTANCEFor humans and mammals, essential amino acids (EAAs) play an important role in maintaining brain function. Therefore, increasing the intake of EAAs by using strains of the yeast Saccharomyces cerevisiae that accumulate EAAs may inhibit neurodegeneration in elderly people and thus contribute to extending healthy lifespan and improving their quality of life. Threonine, an EAA, is synthesized from aspartate. Aspartate kinase (AK) catalyzes the first step in threonine biosynthesis and is subject to allosteric regulation by threonine. Here, we isolated a threonine-accumulating mutant of S. cerevisiae by conventional mutagenesis and identified a mutant gene encoding a novel variant of AK. In contrast to previously isolated variants, the Hom3 variant exhibited AK activity that was insensitive to feedback inhibition by threonine but retained its catalytic ability. This resulted in increased production of threonine in yeast. These findings open up the possibility for the rational design of AK to increase threonine productivity in yeast.

Branched-chain amino acids and the risks of dementia, Alzheimer's disease, and Parkinson's disease

Background

We aimed to examine the association between blood levels of Branched-chain amino acids (BCAAs) - specifically isoleucine, leucine, and valine - and the susceptibility to three neurodegenerative disorders: dementia, Alzheimer's disease (AD), and Parkinson's disease (PD).

Methods

Based on data from the UK Biobank, a Cox proportional hazard regression model and a dose-response relationship were used to analyze the association between BCAAs and the risks of dementia, AD, and PD. We also generated a healthy lifestyle score and a polygenic risk score. Besides, we conducted a sensitivity analysis to ensure the robustness of our findings.

Results

After adjusting for multiple covariates, blood concentrations of isoleucine, leucine, and valine were significantly associated with a reduced risk of dementia and AD. This association remained robust even in sensitivity analyses. Similarly, higher levels of isoleucine and leucine in the blood were found to be associated with an increased risk of PD, but this positive correlation could potentially be explained by the presence of covariates. Further analysis using a dose-response approach revealed that a blood leucine concentration of 2.14 mmol/L was associated with the lowest risk of dementia.

Conclusion

BCAAs have the potential to serve as a biomarker for dementia and AD. However, the specific mechanism through which BCAAs are linked to the development of dementia, AD, and PD remains unclear and necessitates additional investigation.

Duckweed application in nature-based system for water phytoremediation and high-value coproducts at family agrisystem from a circular economy perspective

Duckweeds are widely recognized for their efficiency in the phytoremediation of agricultural and industrial effluents. This study had two main objectives: 1) Implement a Nature-based Solutions (NBS) utilizing the environmental services of duckweeds to improve water quality through phytoremediation in small fish farms; 2) Analysis of duckweeds biomass produced in these fish farms to develop coproducts from a circular economy perspective in family agrisystem in Brazilian Atlantic Forest. The effectiveness of the phytoremediation system was assessed by the reduction of the Trophic State Index (TSI). Phytoremediation in small fish farming NBS was implemented using Clarias gariepinus, employing two different managements approaches: (i) System I - L. minor cultured every 15 days, with biomass harvest and effluent analysis conducted in each cycle over 60 days; (ii) System II - L. minor cultured every 30 days, following a similar cycle and analysis. Additionally, effluent from fish production underwent testing for phytoremediation in a batch system within a climate-controlled laboratory. L. minor demonstrated efficiency in System II, leading to a reduction of the TSI. The dry biomass of the plants emerged as a viable source of amino acid for application in functional foods and feed or nutraceuticals. The findings underscore the potential integration of L. minor into the NBS system and the generation of new co-products from circular production. In addition to its effective phyto- remediation properties, L. minor's dry biomass exhibited appealing characteristics, with elevated levels of crude protein, minerals, fatty acids, and carotenoids. This positions L. minor as a promising candidate for developing bioproducts tailored for functional foods and nutraceuticals. This underscores the potential of duckweeds to produce valuable nutritional compounds beyond their remediation capabilities.

Metabolomics and Risk of Dementia: A Systematic Review of Prospective Studies

BACKGROUND

The projected increase in the prevalence of dementia has sparked interest in understanding the pathophysiology and underlying causal factors in its development and progression. Identifying novel biomarkers in the preclinical or prodromal phase of dementia may be important for predicting early disease risk. Applying metabolomic techniques to prediagnostic samples in prospective studies provides the opportunity to identify potential disease biomarkers.

OBJECTIVE

The objective of this systematic review was to summarize the evidence on the associations between metabolite markers and risk of dementia and related dementia subtypes in human studies with a prospective design.

DESIGN

We searched PubMed, PsycINFO, and Web of Science databases from inception through December 8, 2023. Thirteen studies (mean/median follow-up years: 2.1-21.0 y) were included in the review.

RESULTS

Several metabolites detected in biological samples, including amino acids, fatty acids, acylcarnitines, lipid and lipoprotein variations, hormones, and other related metabolites, were associated with risk of developing dementia. Our systematic review summarized the adjusted associations between metabolites and dementia risk; however, our findings should be interpreted with caution because of the heterogeneity across the included studies and potential sources of bias. Further studies are warranted with well-designed prospective cohort studies that have defined study populations, longer follow-up durations, the inclusion of additional diverse biological samples, standardization of techniques in metabolomics and ascertainment methods for diagnosing dementia, and inclusion of other related dementia subtypes.

CONCLUSIONS

This study contributes to the limited systematic reviews on metabolomics and dementia by summarizing the prospective associations between metabolites in prediagnostic biological samples with dementia risk. Our review discovered additional metabolite markers associated with the onset of developing dementia and may help aid in the understanding of dementia etiology. The protocol is registered in the International Prospective Register of Systematic Reviews (PROSPERO) database (https://www.crd.york.ac.uk/prospero/; registration ID: CRD42022357521).

Enhancing cognitive function in older adults: dietary approaches and implications

Natural aging encompasses physiological and psychological changes that impact overall health and quality of life. Mitigating these effects requires physical and mental exercise, coupled with proper nutrition. Notably, protein malnutrition emerges as a potential risk factor for senile dementia, with insufficient intake correlating with premature cognitive decline. Adequate protein intake in the elderly positively associates with memory function and lowers cognitive impairment risk. Considering diet as a modifiable risk factor for cognitive decline, extensive research has explored diverse dietary strategies to prevent dementia onset in older adults. However, conclusive results remain limited. This review aims to synthesize recent evidence on effective dietary approaches to enhance cognitive function and prognosis in older individuals. Specifically, the study evaluates complex multicomponent programs, protein-rich diets, and branched-chain amino acid supplementation. By addressing the nexus of nutrition and cognitive health, this review contributes to understanding viable interventions for promoting cognitive well-being in aging populations.

New Insights into the Relationship between Nutrition and Neuroinflammation in Alzheimer's Disease: Preventive and Therapeutic Perspectives

Neurodegenerative diseases are progressive brain disorders characterized by inexorable synaptic dysfunction and neuronal loss. Since the most consistent risk factor for developing neurodegenerative diseases is aging, the prevalence of these disorders is intended to increase with increasing life expectancy. Alzheimer's disease is the most common cause of neurodegenerative dementia, representing a significant medical, social, and economic burden worldwide. Despite growing research to reach an early diagnosis and optimal patient management, no disease-modifying therapies are currently available. Chronic neuroinflammation has been recognized as a crucial player in sustaining neurodegenerative processes, along with pathological deposition of misfolded proteins, including amyloid-β and tau protein. Modulating neuroinflammatory responses may be a promising therapeutic strategy in future clinical trials. Among factors that are able to regulate neuroinflammatory mechanisms, diet, and nutrients represent easily accessible and modifiable lifestyle components. Mediterranean diet and several nutrients, including polyphenols, vitamins, and omega-3 polyunsaturated fatty acids, can exert antioxidant and anti-inflammatory properties, impacting clinical manifestations, cognitive decline, and dementia. This review aims to provide an updated overview of the relationship between neuroinflammation, nutrition, gut microbiota, and neurodegeneration. We summarize the major studies exploring the effects of diet regimes on cognitive decline, primarily focusing on Alzheimer's disease dementia and the impact of these results on the design of ongoing clinical trials.

Essential amino acid supplements ingestion has a positive effect on executive function after moderate-intensity aerobic exercise

Aerobic exercise acutely improves cognitive function (e.g., executive function (EF); memory recognition (MR)) and increases circulating brain-derived neurotrophic factor (BDNF). In addition, branched-chain amino acids (BCAA) ingestion acutely shortens the choice reaction time and increases brain BDNF. We examined whether the ingestion of essential amino acid (EAA) supplements (mainly composed of BCAA) would positively impact on cognitive function and circulating BDNF after moderate-intensity aerobic exercise. Twenty-two healthy young men received either an EAA supplements or the placebo (PL) 30 min before undergoing aerobic exercise. The participants performed a cycling exercise at 60% of peak oxygen uptake for 30 min. EF after aerobic exercise was better after the EAA treatment than after the PL treatment (P = 0.02). MR (P = 0.38 for response accuracy; P = 0.15 for reaction time) and circulating BDNF (P = 0.59) were not altered by EAA supplements. EF improvement was correlated with increases in some amino acids (leucine, isoleucine, valine, lysine, phenylalanine; all Ps < 0.05) that are potential substrates for synthesizing neurotransmitters in the brain. These results suggest that EAA supplements ingestion had a positive effect on EF after moderate-intensity aerobic exercise, while MR and BDNF were not altered.

Neuroprotective effect of Tiliacora triandra (Colebr.) Diels leaf extract on scopolamine-induced memory impairment in rats

Alzheimer's disease is characterized by progressive memory loss caused from alterations in the central cholinergic system. While existing medications often have adverse effects, traditional use of Tiliacora triandra in Thailand shows its potential as a revitalizing neurotonic agent. This study explores the impact of T. triandra leaf extract on cognitive behaviors, neuronal density, and oxidative stress in male rats with scopolamine-induced cognitive impairment. Experimental groups composed of a control, vehicle, positive control meditation, and T. triandra extract-treated groups (100, 200, and 400 mg/kg BW) over 14 days, with scopolamine administration (i.p.) between days 8 and 14. Results showed significant enhancements in the discrimination ratio and spontaneous alteration behavior percentage during novel object recognition (NORT) and Y-maze tests for scopolamine-administered rats treated with T. triandra extract or donepezil. In contrast, open field test (OFT)-assessed spontaneous locomotor activity displayed no significant difference. Notably, acetylcholinesterase (AChE) activity and malondialdehyde (MDA) levels reduced significantly in scopolamine-treated rats with T. triandra extract or the positive control. Moreover, neuronal density in the hippocampal CA3 region, superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities increased significantly. However, catalase (CAT) activity exhibited no significant difference. In conclusion, T. triandra leaf extract shows promise in mitigating scopolamine-induced memory deficits, potentially attributed to increased neuronal density, inhibited AChE activity, reduced MDA levels, and enhanced antioxidant activities. This extract has potential as a therapeutic agent for Alzheimer's disease-associated memory impairment.

Cognitive and biomarker responses in healthy older adults to a 18-hole golf round and different walking types: a randomised cross-over study

Introduction

The global burden of age-related cognitive decline is increasing, with the number of people aged 60 and over expected to double by 2050. This study compares the acute effects of age-appropriate cognitively demanding aerobic exercises involving walking, on cognitive functions and exerkine responses such as brain-derived neurotrophic factor (BDNF) and cathepsin B (CTSB) in older, healthy adults.

Methods/design

Healthy older golfers (n=25, 16 male and 9 female, 69±4 years) were enrolled in a 5-day randomised cross-over study and completed three different exercise trials (18-hole golf round, 6 km Nordic walking, 6 km walking) in a real-life environment, in random order and at a self-selected pace. Differences in cognition (the Trail-Making Test (TMT) AB) and exerkines (BDNF and CTSB) were analysed within groups using the Wilcoxon signed-rank test and between groups using the Kruskal-Wallis test.

Results

All exercise types resulted in a significant decrease in the TMT A-test (p<0.05; golf: -4.43±1.5 s, Nordic walking: -4.63±1.6 s, walking: -6.75±2.26 s), where Nordic walking and walking demonstrated a decrease in the TMT B-test (p<0.05; Nordic walking: -9.62±7.2 s, walking: -7.55±3.2 s). In addition, all exercise types produced significant decreases in the TMT AB test scores (p<0.05), and Nordic walking (p=0.035) showed decreases in the TMTB-TMTA-test. There were no immediate postexercise changes in the levels of BDNF or CTSB.

Conclusion

Acute bouts of golf, Nordic walking and walking improved cognitive functions irrespective of exerkines in healthy older adults. In addition, Nordic walking and walking in general enhanced executive functions. No significant effects were seen on the levels of BDNF and CTSB.

Trial registration number

ISRCTN10007294.

Metabolomic Signatures of Alzheimer's Disease Indicate Brain Region-Specific Neurodegenerative Progression

Pathological mechanisms contributing to Alzheimer's disease (AD) are still elusive. Here, we identified the metabolic signatures of AD in human post-mortem brains. Using 1H NMR spectroscopy and an untargeted metabolomics approach, we identified (1) metabolomic profiles of AD and age-matched healthy subjects in post-mortem brain tissue, and (2) region-common and region-unique metabolome alterations and biochemical pathways across eight brain regions revealed that BA9 was the most affected. Phenylalanine and phosphorylcholine were mainly downregulated, suggesting altered neurotransmitter synthesis. N-acetylaspartate and GABA were upregulated in most regions, suggesting higher inhibitory activity in neural circuits. Other region-common metabolic pathways indicated impaired mitochondrial function and energy metabolism, while region-unique pathways indicated oxidative stress and altered immune responses. Importantly, AD caused metabolic changes in brain regions with less well-documented pathological alterations that suggest degenerative progression. The findings provide a new understanding of the biochemical mechanisms of AD and guide biomarker discovery for personalized risk prediction and diagnosis.

Dynamic Interplay between Social Brain Development and Nutrient Intake in Young Children

Myelination of the brain structures underlying social behavior in humans is a dynamic process that parallels the emergence of social-emotional development and social skills in early life. Of the many genetic and environmental factors regulating the myelination processes, nutrition is considered as a critical and modifiable early-life factor for establishing healthy social brain networks. However, the impact of nutrition on the longitudinal development of social brain myelination remains to be fully understood. This study examined the interplay between childhood nutrient intake and social brain development across the first 5 years of life. Myelin-sensitive neuroimaging and food-intake data were analyzed in 293 children, 0.5 to 5 years of age, and explored for dynamic patterns of nutrient-social brain myelin associations. We found three data-driven age windows with specific nutrient correlation patterns, 63 individual nutrient-myelin correlations, and six nutrient combinations with a statistically significant predictive value for social brain myelination. These results provide novel insights into the impact of specific nutrient intakes on early brain development, in particular social brain regions, and suggest a critical age-sensitive opportunity to impact these brain regions for potential longer-term improvements in socio-emotional development and related executive-function and critical-thinking skills.

Metabolic Fingerprints of Effective Fluoxetine Treatment in the Prefrontal Cortex of Chronically Socially Isolated Rats: Marker Candidates and Predictive Metabolites

The increasing prevalence of depression requires more effective therapy and the understanding of antidepressants' mode of action. We carried out untargeted metabolomics of the prefrontal cortex of rats exposed to chronic social isolation (CSIS), a rat model of depression, and/or fluoxetine treatment using liquid chromatography-high resolution mass spectrometry. The behavioral phenotype was assessed by the forced swim test. To analyze the metabolomics data, we employed univariate and multivariate analysis and biomarker capacity assessment using the receiver operating characteristic (ROC) curve. We also identified the most predictive biomarkers using a support vector machine with linear kernel (SVM-LK). Upregulated myo-inositol following CSIS may represent a potential marker of depressive phenotype. Effective fluoxetine treatment reversed depressive-like behavior and increased sedoheptulose 7-phosphate, hypotaurine, and acetyl-L-carnitine contents, which were identified as marker candidates for fluoxetine efficacy. ROC analysis revealed 4 significant marker candidates for CSIS group discrimination, and 10 for fluoxetine efficacy. SVM-LK with accuracies of 61.50% or 93.30% identified a panel of 7 or 25 predictive metabolites for depressive-like behavior or fluoxetine effectiveness, respectively. Overall, metabolic fingerprints combined with the ROC curve and SVM-LK may represent a new approach to identifying marker candidates or predictive metabolites for ongoing disease or disease risk and treatment outcome.

Nutrition, lifestyle, and cognitive performance in esport athletes

Introduction

Electronic sports, termed esports, is a growing athletic activity in which high levels of attention and cognitive performance are required. With its increasing popularity and competitiveness, interest in strategies to improve performance have emerged. Improving esports athlete performance, namely cognitive endurance, and resilience, may lie in nutritional or lifestyle factors. The Nutrition, Vision, and Cognition in Sport Studies (IONSport) investigated nutritional and behavioral factors that can influence cognition via 3-dimensional multiple objects tracking test (3DMOT) via Neurotracker X (NTx) software. The purpose of this study was to characterize the lifestyle of high level esports athletes with detailed nutrition, sleep, and physical activity assessments, and their association to gaming related cognitive performance.

Methods

103 male and 16 elite female esports athletes aged 16 to 35 years old completed surveys, food records, and cognitive testing sessions over 10 days. Participants were instructed to maintain their normal dietary and lifestyle habits.

Results

There were positive significant associations between average NTx scores and the following nutrients: magnesium, phosphorous, potassium, sodium, zinc, selenium, thiamin, niacin, vitamins B6 and B12, folate, cholesterol, saturated, polyunsaturated, and monounsaturated fats, omega-6 and omega-3 fatty acids, and choline. Majority of participants did not meet recommended dietary allowances (RDAs) for these micronutrients nor the recommended intakes for dairy, fruit, and vegetables. There was a significant (p = 0.003) positive (r = 0.272) association between total vegetable intake and average NTx score. There was a significant negative association (p = 0.015) with our final sustain session, which measured cognitive resilience, and the Stanford Sleepiness Scale score. Repeated measures analysis was done with these groups over the 18 core NTx sessions. There were significant (p = 0.018) differences between the two groups with those who consumed the recommended amount of protein or more performing significantly better on NTx over the 18 sessions than those that did not consume enough protein. Those who consumed the recommended intakes for riboflavin, phosphorous, vitamin B12, and selenium performed significantly better over the 18 core NTx sessions than those that did not meet the recommended amounts.

Discussion

The need for a nutrition intervention that is rich in protein, vitamins, and minerals is warranted in this population.

Investigating the causal association between branched-chain amino acids and Alzheimer's disease: A bidirectional Mendelian randomized study

Background

There are many metabolic pathway abnormalities in Alzheimer's disease (AD). Several studies have linked branched-chain amino acid (BCAA) metabolism disorders with AD but have not obtained consistent results. The purpose of this study is to explore the causal association between BCAA concentration and the risk of AD.

Methods

A bidirectional Mendelian randomized (MR) study was applied to explore the causal effect between BCAA level and the risk of AD. Genetic instrumental variables from the genome-wide association study (GWAS) of serum BCAA levels [total BCAAs (115,047 participants), valine (115,048 participants), leucine (115,074 participants), and isoleucine (115,075 participants)] from the UK Biobank and AD (21,982 AD cases and 41,944 controls) from the International Genomics of Alzheimer's Project were applied to explore the causal effect through the inverse variance-weighted (IVW) method, MR-Egger, and weighted median, accompanied by multiple pluripotency and heterogeneity tests.

Results

The forward MR analysis showed that there was no causal effect of total BCAAs (OR: 1.067, 95% CI: 0.838–1.358; p = 0.838), valine (OR: 1.106, 95% CI: 0.917–1.333; p = 0.292), leucine (OR: 1.096, 95% CI: 0.861–1.396; p = 0.659), and isoleucine (OR: 1.457, 95% CI: 1.024–2.742; p = 0.037) levels on the risk of AD. The reverse analysis showed that AD was related to reduced levels of total BCAAs (OR: 0.979, 95% CI: 0.989–0.990; p &lt; 0.001), valine (OR: 0.977, 95% CI: 0.963–0.991; p = 0.001), leucine (OR: 0.983, 95% CI: 0.973–0.994; p = 0.002), and isoleucine (OR: 0.982, 95% CI: 0.971–0.992; p = 0.001).

Conclusion

We provide robust evidence that AD was associated with a decreased level of BCAAs, which can serve as a marker for early diagnosis of AD.

The Food4Years Ageing Network: Improving foods and diets as a strategy for supporting quality of life, independence and healthspan in older adults

By 2050, it is predicted that one in four people in the United Kingdom will be aged 65 years and over. Increases in lifespan are not always translated into years spent in good health. Incidence rates for chronic diseases are increasing, with treatments allowing people to live longer with their disease. There is good evidence to support changes to lifestyle to maintain or improve body composition, cognitive health, musculoskeletal health, immune function and vascular health in older adults. Much research has been done in this area, which has produced significant support for foods and nutrients that contribute to improved healthspan. Yet two major barriers remain: firstly, older adult consumers are not meeting current UK recommendations for macro- and micronutrients that could benefit health and quality of life and secondly, the UK-specific recommendations may not be sufficient to support the ageing population, particularly for nutrients with key physiological roles. More work is needed to improve intakes of specific foods, diets and nutrients by older adults, through a variety of mechanisms including (i) development of specific food products; (ii) improved clarity of information and (iii) appropriate marketing, and policy changes to enable incentives. The Food4Years Ageing Network aims to build a wide-reaching and multidisciplinary community that is committed to the development, integration and communication of healthy, affordable foods and specific diets for all older adults across the UK food landscape. The Network will identify evidence-based strategies for improving food intake and nutrition in older adults, paving the way to "living well while living longer."

Usefulness of the Cognitive Composition Test as an Early Discriminator of Mild Cognitive Impairment

Mild cognitive impairment (MCI) is the preliminary stage of dementia, which is a serious social problem worldwide. This study aimed to investigate whether the Cognitive Composition Test (CCT) is effective for the early diagnosis of MCI. A total of 104 older adults underwent the Montreal Cognitive Assessment (MoCA), the Mini-Mental State Examination (MMSE), the Trail Making Test Parts A (TMT-A) and B (TMT-B), and our newly prototyped cognitive composition test (CCT). We created three types of CCT (CCT-A, CCT-B, and CCT-C) with different degrees of difficulty. First, we examined the concurrent validity of CCT-A, CCT-B, and CCT-C with the MoCA, MMSE, TMT-A, and TMT-B. All participants were classified into the healthy control (HC) and MCI groups based on their scores in the Japanese versions of the MoCA and MMSE. The HC and MCI groups were compared using the TMT-A, TMT-B, CCT-A, CCT-B, and CCT-C. Finally, we examined the sensitivity for discrimination of CCT-C. CCT-C had a higher discrimination sensitivity than TMT-A, TMT-B, CCT-A, and CCT-B, with a cut-off value of 65.75 s, a sensitivity level of 0.844, and a specificity of 0.776. It may be a useful screening tool for the early diagnosis of the early-stages of dementia, such as MCI, in asymptomatic older adults.

Acute Benefits of Acidified Milk Drinks with 10-g and 15-g Protein on Shifting and Updating Performances in Young Adults: A Randomized Controlled Trial

BACKGROUND

Accumulating evidence has shown that protein-rich milk drinks can rapidly improve cognitive performance. However, the optimum doses of milk protein that are needed to improve cognitive function remain to be investigated.

OBJECTIVE

This study aimed to determine whether acidified milk drinks with 10-g and 15-g milk protein have acute benefits on key cognitive functions in healthy young adults.

DESIGN

In this double-blinded randomized control trial, 66 young adults were randomly assigned to one of three groups (0-g, 10-g, and 15-g milk protein groups). Key cognitive functions (processing speed, inhibition, shifting, updating, and working memory capacity) were assessed before and 15 and 60 min after the drink intake.

RESULTS

We found that the shifting performance improved at 15 min after intake of the acidified 10-g and 15-g milk protein drinks compared to intake of the 0-g milk protein drink, and this acute effect of the acidified 15-g milk protein drink lasted for 60 min. In addition, updating performance improved at 60 min after intake of the acidified 10-g and 15-g milk protein drinks compared to intake of the 0-g milk protein drink.

CONCLUSION

Our findings suggest that the acidified 10-g and 15-g milk protein drinks have an acute benefit on shifting and updating performance in healthy young adults.

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

BACKGROUND AND OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Decreased circulating branched-chain amino acids are associated with development of Alzheimer's disease in elderly individuals with mild cognitive impairment

Background

Nutritional epidemiology has shown that inadequate dietary protein intake is associated with poor brain function in the elderly population. The plasma free amino acid (PFAA) profile reflects nutritional status and may have the potential to predict future changes in cognitive function. Here, we report the results of a 2-year interim analysis of a 3-year longitudinal study following mild cognitive impairment (MCI) participants.

Method

In a multicenter prospective cohort design, MCI participants were recruited, and fasting plasma samples were collected. Based on clinical assessment of cognitive function up to 2 years after blood collection, MCI participants were divided into two groups: remained with MCI or reverted to cognitively normal ("MCI-stable," N = 87) and converted to Alzheimer's disease (AD) ("AD-convert," N = 68). The baseline PFAA profile was compared between the two groups. Stratified analysis based on apolipoprotein E ε4 (APOE ε4) allele possession was also conducted.

Results

Plasma concentrations of all nine essential amino acids (EAAs) were lower in the AD-convert group. Among EAAs, three branched-chain amino acids (BCAAs), valine, leucine and isoleucine, and histidine (His) exhibited significant differences even in the logistic regression model adjusted for potential confounding factors such as age, sex, body mass index (BMI), and APOE ε4 possession (p < 0.05). In the stratified analysis, differences in plasma concentrations of these four EAAs were more pronounced in the APOE ε4-negative group.

Conclusion

The PFAA profile, especially decreases in BCAAs and His, is associated with development of AD in MCI participants, and the difference was larger in the APOE ε4-negative population, suggesting that the PFAA profile is an independent risk indicator for AD development. Measuring the PFAA profile may have importance in assessing the risk of AD conversion in the MCI population, possibly reflecting nutritional status.

Clinical trial registration

[https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000025322], identifier [UMIN000021965].

Non-drug Therapies for Alzheimer's Disease: A Review

Alzheimer's disease (AD) is a debilitating disease leading to great social and economic burdens worldwide. During the past decades, increasing understanding of this disease enables dynamic trials for disease interventions. Unfortunately, at present, AD still remains uncurable, and therefore, developing intervention strategies for improving symptoms and slowing down the disease process becomes a practical focus in parallel with searching for a disease-modifying medication. The aim of this review is to summarize the outcomes of AD clinical trials of non-drug therapies published in the past decade, including cognitive-oriented interventions, physical exercise interventions, brain stimulation, as well as nutrition supplementations, to find out the most effective interventions in the category by looking through the primary and secondary outcomes. The outcomes of the trials could be varied with the interventional approaches, the tested cohorts, the settings of observing outcomes, and the duration of follow-ups, which are all discussed in this review. Hence, we hope to provide crucial information for application of these interventions in real-world settings and assist with optimization of clinical trial designs in this area.

Association between egg consumption and cognitive function among Chinese adults: long-term effect and interaction effect of iron intake

The association between egg consumption and cognitive function is inclusive. We aimed to assess the association between egg consumption and cognitive function in Chinese adults and tested the interaction between egg consumption and Fe intake. The data used were from a nationwide sample (n 4852, age ≥ 55 years) from the China Health and Nutrition Survey between 1991 and 2006. Assessment of cognitive function was conducted in 1997, 2000, 2004 and 2006. Dietary egg intake was obtained by 24-h dietary recalls of 3 consecutive days during home visits between 1991 and 2006. Multivariable mixed linear regression and logistic regression were used. Egg intake was positively associated with global cognitive function. In fully adjusted models, across the quartiles of egg intake the regression coefficients were 0, 0·11 (95 % CI -0·28, 0·51), 0·79 (95 % CI 0·36, 1·22) and 0·92 (95 % CI 0·43, 1·41), respectively. There was a significant interaction between egg intake and Fe intake. The association between high egg intake and cognitive function was stronger among those with low Fe intake than those with high Fe intake. In addition, there was a significant interaction between egg consumption and sex, with the association mainly observed in women but not men. Furthermore, compared with non-consumers, those with higher egg consumption (Q4) had the OR of 0·93 (95 % CI 0·74, 1·19), 0·84 (95 % CI 0·69, 1·02) for self-reported poor memory and self-reported memory decline, respectively. Higher egg intake is associated with better cognition in Chinese adults among those with low Fe intake.

Metabolomic profiling relates tianeptine effectiveness with hippocampal GABA, myo-inositol, cholesterol, and fatty acid metabolism restoration in socially isolated rats

RATIONALE

Discovering biomarkers of major depressive disorder (MDD) can give a deeper understanding of this mood disorder and improve the ability to screen for, diagnose, and treat MDD.

OBJECTIVES

In this study, metabolomics was used in unraveling metabolite fluctuations of MDD and drug outcome by creating specific metabolomic fingerprints. We report metabolomic patterns of change of the hippocampus of adult male Wistar rats following chronic social isolation (CSIS) (6 weeks), an animal model of depression, and/or chronic tianeptine (Tian) treatment (10 mg kg^-1 per day) (lasting 3 weeks of 6-week CSIS), monitored by using comprehensive GC × GC-MS.

RESULTS

The comparative metabolomic analysis highlighted the role of gamma aminobutyric acid (GABA), iso-allocholate, and unsaturated fatty acid metabolism alterations following the CSIS, which was corroborated with moderate to strong negative Pearson's correlation of GABA, docosahexaenoic, 9-hexadecenoic acid, 5,8,11,14-eicosatetraynoic, and arachidonic acids with immobility behavior in the forced swim test. The antidepressant effect of Tian restored GABA levels, which was absent in Tian resilient rats. Tian decreased myo-inositol and increased TCA cycle intermediates, amino acids, and cholesterol and its metabolite. As key molecules of divergence between Tian effectiveness and resilience, metabolomics revealed myo-inositol, GABA, cholesterol, and its metabolite. A significant moderate positive correlation between myo-inositol and immobility was revealed. Tian probably acted by upregulating NMDAR's and α₂ adrenergic receptors (AR) or norepinephrine transporter in both control and stressed animals.

CONCLUSION

Metabolomics revealed several dysregulations underlying CSIS-induced depressive-like behavior and responsiveness to Tian, predominantly converging into NMDAR-mediated glutamate and myo-inositol signalization and GABA inhibitory pathways.

Plasma metabolomic profiles of dementia: a prospective study of 110,655 participants in the UK Biobank

BACKGROUND

Plasma metabolomic profile is disturbed in dementia patients, but previous studies have discordant conclusions.

METHODS

Circulating metabolomic data of 110,655 people in the UK Biobank study were measured with nuclear magnetic resonance technique, and incident dementia records were obtained from national health registers. The associations between plasma metabolites and dementia were estimated using Cox proportional hazard models. The 10-fold cross-validation elastic net regression models selected metabolites that predicted incident dementia, and a 10-year prediction model for dementia was constructed by multivariable logistic regression. The predictive values of the conventional risk model, the metabolites model, and the combined model were discriminated by comparison of area under the receiver operating characteristic curves (AUCs). Net reclassification improvement (NRI) was used to estimate the change of reclassification ability when adding metabolites into the conventional prediction model.

RESULTS

Amongst 110,655 participants, the mean (standard deviation) age was 56.5 (8.1) years, and 51 186 (46.3%) were male. A total of 1439 (13.0%) developed dementia during a median follow-up of 12.2 years (interquartile range: 11.5-12.9 years). A total of 38 metabolites, including lipids and lipoproteins, ketone bodies, glycolysis-related metabolites, and amino acids, were found to be significantly associated with incident dementia. Adding selected metabolites (n=24) to the conventional dementia risk prediction model significantly improved the prediction for incident dementia (AUC: 0.824 versus 0.817, p =0.042) and reclassification ability (NRI = 4.97%, P = 0.009) for identifying high risk groups.

CONCLUSIONS

Our analysis identified various metabolomic biomarkers which were significantly associated with incident dementia. Metabolomic profiles also provided opportunities for dementia risk reclassification. These findings may help explain the biological mechanisms underlying dementia and improve dementia prediction.

Normative Data of the Trail Making Test Among Urban Community-Dwelling Older Adults in Japan

Introduction

Population aging is likely to increase the number of people with dementia living in urban areas. The Trail Making Test (TMT) is widely used as a cognitive task to measure attention and executive function among older adults. Normative data from a sample of community-dwelling older adults are required to evaluate the executive function of this population. The purpose of this study was to examine the Trail Making Test completion rate and completion time among urban community-dwelling older adults in Japan.

Methods

A survey was conducted at a local venue or during a home visit (n = 1,966). Cognitive tests were conducted as a part of the survey, and TMT Parts A (TMT-A) and B (TMT-B) were completed after the completion of the Japanese version of the Mini-Mental State Examination (MMSE-J). Testers recorded TMT completion status, completion time, and the number of errors observed.

Results

In the TMT-A, 1,913 (99.5%) participants understood the instructions, and 1,904 (99.1%) participants completed the task within the time limit of 240 s. In the TMT-B, 1,839 (95.9%) participants understood the instructions, and 1,584 (82.6%) participants completed the task within the time limit of 300 s. The completion rate of TMT-B was 90.2 and 41.8% for participants with an MMSE-J score of >23 points and ≦23 points, respectively. Results of multiple regression analyses showed that age, education, and the MMSE-J score were associated with completion time in both TMTs.

Conclusion

In both TMTs, completion time was associated with age, education, and general cognitive function. However, not all participants completed the TMT-B, and the completion rate was relatively low among participants with low MMSE-J scores. These findings may help interpret future TMT assessments.

Effect of Fermentation on the Bioactive Compounds of the Black Soybean and Their Anti-Alzheimer’s Activity

Black soybean is one of the nutritious crops and is being used in traditional medicines in Asian countries. In the present study, we fermented black soybean and screened against in vitro Alzheimer’s disease (AD) biomarkers such as cholinesterase enzymes, inflammatory factors, oxidative stress, and presence of γ-aminobutyric acid (GABA) levels. Firstly, we fermented black soybean with different lactic acid bacteria (LABs) and selected the Pediococcus acidilactici as the best LAB on the basis of GABA levels in the fermentate. We have found that black soybean fermented with P. acidilactici significantly inhibited the inflammatory factors (proteinase, protein denaturation, and lipoxygenase) and cholinesterase enzymes than non-fermented samples. An increase in the antioxidant capacity (FRAP, ABTS, and DPPH), anthocyanins, phenolics, flavonoids, and GABA content was also observed in fermented samples. Moreover, UHPLC-ESI-QTOF-MS/MS technique identified 38 bioactive components, including polyphenols, amino acids, and fatty acids. Among identified components, eight bioactive compounds were quantified, and an increase in the concentration of daidzein, genistein, glycitein, (+)-catechin, quercetin, and gallic acid was observed in fermented samples. However, the concentration of rutin and soyasaponin was higher in raw samples. These results indicated that fermentation of black soybean with P. acidilactici is a promising approach that can be used to develop functional foods to inhibit/prevent AD and other neurodegenerative diseases.

Development of a Novel Nutrition-Related Multivariate Biomarker for Mild Cognitive Impairment Based on the Plasma Free Amino Acid Profile

Nutritional epidemiology has shown the importance of protein intake for maintaining brain function in the elderly population. Mild cognitive impairment (MCI) may be associated with malnutrition, especially protein intake. We explored blood-based biomarkers linking protein nutritional status with MCI in a multicenter study. In total, 219 individuals with MCI (79.5 ± 5.7 year) from 10 institutions and 220 individuals who were cognitively normal (CN, 76.3 ± 6.6 year) in four different cities in Japan were recruited. They were divided into the training (120 MCI and 120 CN) and validation (99 MCI and 100 CN) groups. A model involving concentrations of PFAAs and albumin to discriminate MCI from CN individuals was constructed by multivariate logistic regression analysis in the training dataset, and the performance was evaluated in the validation dataset. The concentrations of some essential amino acids and albumin were significantly lower in MCI group than CN group. An index incorporating albumin and PFAA discriminated MCI from CN participants with the AUC of 0.705 (95% CI: 0.632–0.778), and the sensitivities at specificities of 90% and 60% were 25.3% and 76.8%, respectively. No significant association with BMI or APOE status was observed. This cross-sectional study suggests that the biomarker changes in MCI group may be associated with protein nutrition.

Comprehensive profiling of bioactive compounds in germinated black soybeans via UHPLC-ESI-QTOF-MS/MS and their anti-Alzheimer's activity

Black soybeans contain several bioactive compounds and commonly consumed due to their health-related activities but rarely cultivated as edible sprouts. The present study investigated the changes that occurred during germination in two new genotypes black soybeans. Raw and germinated seeds were tested against in vitro Alzheimer's disease (AD) biomarkers, including oxidative stress, inflammatory factors and cholinesterase enzymes as well as γ-aminobutyric acid (GABA) levels. Sprouts significantly inhibited the cholinesterase enzymes and inflammatory factors (protein denaturation, proteinase and lipoxygenase) than seeds. An increase in phenolic, flavonoid and GABA (10-folds) content and antioxidant capacity (ABTS, DPPH, and FRAP) was observed in germinated seeds. However, anthocyanin content was decreased in sprouts. UHPLC-ESI-QTOF-MS2 metabolites profiling approach identified 22 compounds including amino acids, peptides, fatty acids, and polyphenols. Among identified compounds, daidzein, genistein, gallic acid, spermidine, L-asparagine, and L-lysine exhibited the highest increase after germination. The current study reveals that germination of black soybeans have promising potential to inhibit/prevent AD and can be used to develop functional foods.

Neurodegenerative processes accelerated by protein malnutrition and decelerated by essential amino acids in a tauopathy mouse model

Protein malnutrition is epidemiologically suggested as a potential risk factor for senile dementia, although molecular mechanisms linking dietary proteins and amino acids to neurodegeneration remain unknown. Here, we show that a low-protein diet resulted in down-regulated expression of synaptic components and a modest acceleration of brain atrophy in mice modeling neurodegenerative tauopathies. Notably, these abnormal phenotypes were robustly rescued by the administration of seven selected essential amino acids. The up-regulation of inflammation-associated gene expression and progressive brain atrophy in the tauopathy model were profoundly suppressed by treatment with these essential amino acids without modifications of tau depositions. Moreover, the levels of kynurenine, an initiator of a pathway inducing neuroinflammatory gliosis and neurotoxicity in the brain, were lowered by treatment through inhibition of kynurenine uptake in the brain. Our findings highlight the importance of specific amino acids as systemic mediators of brain homeostasis against neurodegenerative processes.