DHA supplementation improved both memory and reaction time in healthy young adults: a randomized controlled trial

Acute effects of mango leaf extract on cognitive function in healthy adults: a randomised, double-blind, placebo-controlled crossover study

Introduction

Extracts made from the leaves of the edible mango plant (Mangifera indica L., Anacardiaceae) have a long history of medicinal usage, most likely due to the presence of high levels of mangiferin, a polyphenol compound. Previous research has demonstrated that mango leaf extract (MLE) can beneficially modulate cognitive function in both animals and humans. This study aimed to assess the effects of an acute dose of 300 mg MLE (standardised to contain ≥60% mangiferin) on cognitive performance and mood in healthy adults.

Methods

In this double-blind, placebo-controlled, crossover study, 114 healthy men and women (18-43 years) received either MLE or a matched placebo at each testing visit (separated by at least 7 days). Cognitive performance (including the cognitive demand battery) and mood were measured at 30, 180, and 300 min post-dose.

Results

The results showed that, compared to placebo, the group taking MLE displayed a significant increase in serial 3 s and serial 7 s subtraction errors overall. There were no other significant effects on cognitive performance.

Discussion

The results of the current study suggest that the consumption of 300 mg MLE in the absence of an observed multitasking psychological stressor does not improve cognitive performance or mood at up to 300 min post-dose. Due to the very limited nature of the effects and since they were observed among many analyses, these findings should be treated with caution.Clinical trial registration: http://ClinicalTrials.gov, identifier [NCT05182450].

Effects of APOE4 on omega-3 brain metabolism across the lifespan

Omega-3 (n-3) polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA), have important roles in human nutrition and brain health by promoting neuronal functions, maintaining inflammatory homeostasis, and providing structural integrity. As Alzheimer's disease (AD) pathology progresses, DHA metabolism in the brain becomes dysregulated, the timing and extent of which may be influenced by the apolipoprotein E ε4 (APOE4) allele. Here, we discuss how maintaining adequate DHA intake early in life may slow the progression to AD dementia in cognitively normal individuals with APOE4, how recent advances in DHA brain imaging could offer insights leading to more personalized preventive strategies, and how alternative strategies targeting PUFA metabolism pathways may be more effective in mitigating disease progression in patients with existing AD dementia.

Omega-3 polyunsaturated fatty acids supplementation improves memory in first-diagnosed, drug-naïve patients with depression: Secondary analysis of data from a randomized controlled trial

INTRODUCTION

Cognitive impairments are found in most patients with major depressive disorder (MDD). It is believed that low Omega-3 polyunsaturated fatty acids (n-3 PUFAs) level raise the risk of anxiety, depressive symptoms and cognition dysfunction. Since our previous research has found n-3 PUFAs supplementation improves anxiety in MDD, this study was to further explore the effectiveness on cognitive impairment among depressed patients.

METHODS

A total of 72 venlafaxine treated outpatients with first-diagnosed, drug-naïve depression were enrolled. Daily n-3 PUFAs supplementation (2.4 g/d of fish oil, including 1440 mg eicosapentaenoic acid and 960 mg of docosahexaenoic acid) or placebo was used for 12 weeks. Cognitive function, measure by repeatable battery for the assessment of neuropsychological status ([RBANS]) scores, was compared over time.

RESULTS

Immediate memory, delayed memory and RBANS total scores were significant higher in both groups at week 4 and week 12 compared with baseline. Both groups exhibited improvement on attention scores at week 12. No significant differences were observed comparing n-3 PUFAs with placebo groups in the improvement of total RBANS scores and other subscales except in the change of immediate memory at both week 4 and week 12 (p < 0.05).

LIMITATIONS

Sample size was relatively low. Moreover, multiple ethnic populations and the income of patients should be considered. Lastly, we used raw scores instead of the standardized scores of RBANS.

CONCLUSION

N-3 PUFAs supplementation yielded a small but statistically significant improvement on immediate memory in first-diagnosed, drug-naïve depressed patients. While, antidepressant treatment resulted in significant improvement of cognitive function.

Recent advances in edible insect processing technologies

Alternative foods have emerged as one of the hot research topics aiming at alleviating food shortage. Insects are one of the alternative foods due to their rich nutrients. Processing is a critical step to develop insect foods, while there is a lack of comprehensive reviews to summarize the main studies. This review aims to demonstrate different processing methods in terms of their impact on insect nutrition and their potential risks. Heat treatments such as boiling and blanching show a negative effect on insect nutrition, but essential to assure food safety. Insects treated by high-pressure hydrostatic technology (HPP) and cold atmospheric pressure plasma (CAPP) can achieve a similar sterilization effect but retain the nutritional and sensory properties. Drying is a practical processing method for industrial insect production, where oven drying serves as a cost-effective method yielding products comparable in quality to freeze-dried ones. In terms of extraction technology, supercritical carbon dioxide and ultrasound-assisted technology can improve the extraction efficiency of proteins and lipids from insects, enhance the production of composite insect-fortified foods, and thus facilitate the development of the insect food industry. To address the widespread negative perceptions and low acceptance towards insect foods among consumers, the primary development direction of the insect food industry may involve creating composite fortified foods and extracting insect-based food components.

Dietary Intakes of Long-Chain Polyunsaturated Fatty Acids and Impulsivity: Comparing Non-Restricted, Vegetarian, and Vegan Diets

BACKGROUND

Research suggests a link between deficiencies in omega-3 long-chain polyunsaturated fatty acids (LCPUFAs) and impulsivity among psychiatric populations. However, this association is less evident in non-clinical populations. As omega-3 LCPUFAs are predominantly sourced through fish consumption, non-fish dieters may be more vulnerable to higher impulsivity.

METHODS

This cross-sectional observational study explored the association between lower intakes of omega-3 LCPUFA food sources and higher self-reported measures of impulsivity among healthy adults consuming non-restricted, vegetarian, and vegan diets.

RESULTS

The results from the validated Food Frequency Questionnaire showed significantly lower estimated omega-3 LCPUFA intakes among vegans and vegetarians when compared with people consuming non-restricted diets. Furthermore, although all groups scored within the normal range of impulsivity measures, vegans scored comparatively higher. Vegans also scored significantly higher in impulsivity control relating to attention than those consuming non-restricted diets.

CONCLUSIONS

The significantly lower omega-3 LCPUFA dietary intakes in the vegan diets were associated with higher scores in the second-order attentional aspect of self-reported impulsiveness.

A case for seeking sex-specific treatments in Alzheimer's disease

There is no satisfactory explanation for the sex-related differences in the incidence of many diseases and this is also true of Alzheimer's disease (AD), where females have a higher lifetime risk of developing the disease and make up about two thirds of the AD patient population. The importance of understanding the cause(s) that account for this disproportionate distribution cannot be overestimated, and is likely to be a significant factor in the search for therapeutic strategies that will combat the disease and, furthermore, potentially point to a sex-targeted approach to treatment. This review considers the literature in the context of what is known about the impact of sex on processes targeted by drugs that are in clinical trial for AD, and existing knowledge on differing responses of males and females to these drugs. Current knowledge strongly supports the view that trials should make assessing sex-related difference in responses a priority with a focus on exploring the sex-stratified treatments.

Nutrition as the foundation for successful aging: a focus on dietary protein and omega-3 polyunsaturated fatty acids

Skeletal muscle plays a critical role throughout the aging process. People living with sarcopenia, a progressive and generalized loss of skeletal muscle mass and function, often experience diminished quality of life, which can be attributed to a long period of decline and disability. Therefore, it is important to identify modifiable factors that preserve skeletal muscle and promote successful aging (SA). In this review, SA was defined as (1) low cardiometabolic risk, (2) preservation of physical function, and (3) positive state of wellbeing, with nutrition as an integral component. Several studies identify nutrition, specifically high-quality protein (eg, containing all essential amino acids), and long-chain omega-3 polyunsaturated fatty acids (n-3 PUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), as positive regulators of SA. Recently, an additive anabolic effect of protein and n-3 PUFAs has been identified in skeletal muscle of older adults. Evidence further suggests that the additive effect of protein and n-3 PUFAs may project beyond skeletal muscle anabolism and promote SA. The key mechanism(s) behind the enhanced effects of intake of protein and n-3 PUFAs needs to be defined. The first objective of this review is to evaluate skeletal muscle as a driver of cardiometabolic health, physical function, and wellbeing to promote SA. The second objective is to examine observational and interventional evidence of protein and n-3 PUFAs on skeletal muscle to promote SA. The final objective is to propose mechanisms by which combined optimal intake of high-quality protein and n-3 PUFAs likely play a key role in SA. Current evidence suggests that increased intake of protein above the Recommended Dietary Allowance and n-3 PUFAs above the Dietary Guidelines for Americans recommendations for late middle-aged and older adults is required to maintain skeletal muscle mass and to promote SA, potentially through the mechanistical target of rapamycin complex 1 (mTORC1).

Neuroprotective and antioxidant effects of docosahexaenoic acid (DHA) in an experimental model of multiple sclerosis

Multiple sclerosis (MS) is a chronic demyelinating disease, whose etiology is not yet fully understood, although there are several factors that can increase the chances of suffering from it. These factors include nutrition, which may be involved in the pathogenesis of the disease. In relation to nutrition, docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid (n-3 PUFA), has emerged as an important player in the regulation of neuroinflammation, being considered a pleiotropic molecule. This study aimed to evaluate the effect of DHA supplementation on clinical state and oxidative stress produced by experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Twenty-five Dark Agouti rats which were used divided into Control Group, Control+Vehicle Group, Control+DHA Group, EAE Group, and EAE+DHA Group. DHA was administered for 51 days by intraperitoneal (i.p.) injection at a dose of 40 mg/kg, once a day, 5 days a week. DHA supplementation produced a decrease in oxidative stress, as well as an improvement in the clinical score of the disease. DHA could exert a beneficial effect on the clinic of MS, through the activation of the antioxidant factor Nrf2.

Omega-3 supplementation improves depressive symptoms, cognitive function and niacin skin flushing response in adolescent depression: A randomized controlled clinical trial

BACKGROUND

Depressive disorder in adolescents is a major health problem with inadequate treatment. Omega-3 (ω3) polyunsaturated fatty acids are a promising adjuvant therapy in adult depression. The primary objective of this study was to investigate the efficacy of adjuvant ω3 treatment on depressive symptoms in adolescent depression. Secondarily, we explored the effects of ω3 on cognitive function and memory and niacin skin flushing response (NSFR), as their robust associations with adolescent depression.

METHODS

A total of 71 adolescents with depression (aged 13-24; 59.2 % female) were randomly assigned to receive ω3 plus Paxil (n = 34) or Paxil alone (n = 37) for 12 weeks. Primary outcome was depression severity according to scores on Montgomery-Asberg Depression Rating Scale (MADRS). Secondary outcomes were cognitive function and memory, and NSFR.

RESULTS

Significant improvements in depressive symptoms over time (p = 0.00027 at week 12) were observed in the ω3 + Paxil group compared with Paxil group. Additionally, in the ω3 + Paxil group, significant improvements in memory over time, and greater cognitive function and NSFR were also observed compared with the Paxil group; the NSFR was negatively correlated with MADRS scores at baseline.

LIMITATIONS

The trial was open label; thus, the outcome measures should be viewed as preliminary since inherent bias in outcomes due to the potential of a placebo effect.

CONCLUSIONS

Our results demonstrate that adjuvant ω3 treatment is effective for reducing depressive symptoms as well as improving cognitive function, memory and the NSFR; these results suggest ω3 is a promising adjuvant treatment for adolescent depression.

Effects of DHA on cognitive dysfunction in aging and Alzheimer's disease: The mediating roles of ApoE

The prevalence of Alzheimer's disease (AD) continues to rise due to the increasing aging population. Among the various genetic factors associated with AD, apolipoprotein E (ApoE), a lipid transporter, stands out as the primary genetic risk factor. Specifically, individuals carrying the ApoE4 allele exhibit a significantly higher risk. However, emerging research indicates that dietary factors play a prominent role in modifying the risk of AD. Docosahexaenoic acid (DHA), a prominent ω-3 fatty acid, has garnered considerable attention for its potential to ameliorate cognitive function. The intricate interplay between DHA and the ApoE genotype within the brain, which may influence DHA's utilization and functionality, warrants further investigation. This review meticulously examines experimental and clinical studies exploring the effects of DHA on cognitive decline. Special emphasis is placed on elucidating the role of ApoE gene polymorphism and the underlying mechanisms are discussed. These studies suggest that early DHA supplementation may confer benefits to cognitively normal older adults carrying the ApoE4 gene. However, once AD develops, ApoE4 non-carriers may experience greater benefits compared to ApoE4 carriers, although the overall effectiveness of DHA supplementation at this stage is limited. Potential mechanisms underlying these differential effects may include accelerated DHA catabolism in ApoE4 carriers, impaired transport across the blood-brain barrier (BBB), and compromised lipidation and circulatory function in ApoE4 carriers. Thus, the supplementation of DHA may represent a potential intervention strategy aimed at compensating for these deficiencies in ApoE4 carriers prior to the onset of AD.

The Association between Metformin Use and Risk of Developing Severe Dementia among AD Patients with Type 2 Diabetes

This study explores the potential impact of metformin on the development of severe dementia in individuals with Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM). With an emerging interest in the role of the APOE genotype in mediating metformin's effects on cognitive decline in AD patients, we sought to investigate whether metformin usage is associated with a reduced risk of severe dementia. Using data from the National Alzheimer's Coordinating Center (NACC) database (2005-2021), we identified 1306 participants with both AD and T2DM on diabetes medications. These individuals were categorized based on metformin usage, and a propensity score-matched cohort of 1042 participants was analyzed. Over an average follow-up of 3.6 years, 93 cases of severe dementia were observed. A Kaplan-Meier analysis revealed that metformin users and non-users had similar probabilities of remaining severe dementia-free (log-rank p = 0.56). Cox proportional hazards models adjusted for covariates showed no significant association between metformin usage and a lower risk of severe dementia (HR, 0.96; 95% CI, 0.63-1.46; p = 0.85). A subgroup analysis based on APOE ε4 carrier status demonstrated consistent results, with metformin use not correlating with a reduced severe dementia risk. In conclusion, our findings from a substantial cohort of AD and T2DM patients suggest that metformin usage is not significantly associated with a decreased risk of severe dementia. This observation persists across APOE ε4 carriers and non-carriers, indicating a lack of genotype-mediated effect.

Potential Clinical Applications of Pro-Resolving Lipids Mediators from Docosahexaenoic Acid

Docosahexaenoic acid (C22:6n-3, DHA) is the precursor of specialized pro-resolving lipid mediators (SPMs), such as resolvin, protectin, and maresin families which have been considered therapeutic bioactive compounds for human health. Growing evidence indicates that DHA and SPMs are beneficial strategies in the amelioration, regulation, and duration of inflammatory processes through different biological actions. The present review discusses the reported therapeutic benefits of SPMs on various diseases and their potential clinical applications.

A Systematic Review of Omega-3 Consumption and Neuroprotective Cognitive Outcomes

Context

While a great deal of interest has been accorded to the cognitive effects of n-3 long-chain polyunsaturated fatty acids (LC PUFAs), there is a need for systematic review data that assess this outcome across the lifespan, accounting for population differences and highlighting methodological limitations of extant studies.

Objective

This systematic review addresses the effects of n-3s on human cognition and provides an overview on the current state of research and recommendations for future efforts.

Data Sources

Based on a thorough review of highly powered articles from PubMed (MEDLINE), Web of Science, and ProQuest Central, the authors evaluated articles published between 2000 and 2020 assessing LC PUFA status on cognition as a primary outcome measure. Using the PRISMA guidelines, the researchers' primary aim was to provide a comprehensive overview of the articles.

Conclusions

The results indicate inconsistent effects of intervention, with benefits for specific groups on specific outcomes. Although results were rarely definitive across cognitive domains, and the majority of studies indicated the presence of a possible threshold effect in which LC PUFA needs were already being met, and supplementation did not have an additional effect, there is evidence for trends towards benefit in cognitive functions, in those experiencing early cognitive decline.

Measuring brain docosahexaenoic acid turnover as a marker of metabolic consumption

Docosahexaenoic acid (DHA, 22:6n-3) accretion in brain phospholipids is critical for maintaining the structural fluidity that permits proper assembly of protein complexes for signaling. Furthermore, membrane DHA can by released by phospholipase A₂ and act as substrate for synthesis of bioactive metabolites that regulate synaptogenesis, neurogenesis, inflammation, and oxidative stress. Thus, brain DHA is consumed through multiple pathways including mitochondrial β-oxidation, autoxidation to neuroprostanes, as well as enzymatic synthesis of bioactive metabolites including oxylipins, synaptamide, fatty-acid amides, and epoxides. By using models developed by Rapoport and colleagues, brain DHA loss has been estimated to be 0.07-0.26 μmol DHA/g brain/d. Since β-oxidation of DHA in the brain is relatively low, a large portion of brain DHA loss may be attributed to synthesis of autoxidative and bioactive metabolites. In recent years, we have developed a novel application of compound specific isotope analysis to trace DHA metabolism. By the use of natural abundance in ¹³C-DHA in food supply, we are able to trace brain phospholipid DHA loss in free-living mice with estimates ranging from 0.11 to 0.38 μmol DHA/g brain/d, in reasonable agreement with previous methods. This novel fatty acid metabolic tracing methodology should improve our understanding of the factors that regulate brain DHA metabolism.

Post-Prandial Cognitive and Blood Pressure Effects of a DHA-Rich Omega-3 Powder in Middle-Aged Males: A Pilot Study

The use of omega-3 polyunsaturated fatty acid (ω-3 PUFA) supplements is increasingly common among middle-aged and older adults. Users of ω-3 PUFA supplements often report using such supplements to support cognitive health, despite mixed findings reported within the ω-3 PUFA literature. To date, very few studies have explored cognitive effects in distinctly middle-aged (40 to 60 years) adults, and none have examined the acute effects (in the hours following a single dose) on cognitive performance. The current study evaluated whether a single dose of ω-3 PUFA (4020 mg docosahexaenoic acid and 720 mg eicosapentaenoic acid) influences cognitive performance and cardiovascular function in middle-aged males. Cognitive performance and cardiovascular function were assessed before and 3.5-4 h after consumption of a high dose of ω-3 PUFA (DHA + EPA) or placebo, incorporated into a standardized meal (i.e., single serve of Greek yogurt). In this study of middle-aged males, no significant differential treatment effects were observed for cognitive performance. However, a significant reduction in aortic systolic blood pressure (pre-dose to post-dose) was apparent following consumption of the ω-3 PUFA (DHA + EPA) treatment (mean difference = -4.11 mmHg, p = 0.004) but not placebo (mean difference = -1.39 mmHg, p = 0.122). Future replication in a sample comprising females, as well as patients with hypertension, is merited.

Sex differences in hippocampal-dependent memory and the hippocampal lipidome in adolescent rats raised on diets with or without DHA

Recent studies suggest the effects of DHA supplementation on human memory may differ between females and males during infancy, adolescence, and early adulthood, but the underlying mechanisms are not clear. As a result, this study sought to examine the spatial memory and brain lipidomic profiles in female and male adolescent rats with or without a DHA-enriched diet that began perinatally with the supplementation of dams. Spatial learning and memory were examined in adolescent rats using the Morris Water Maze beginning at 6 weeks of age and animals were sacrificed at 7 weeks of age to permit isolation of brain tissue and blood samples. Behavioral testing showed that there was a significant diet x sex interaction for two key measures of spatial memory (distance to zone and time spent in the correct quadrant during the probe test), with female rats benefiting the most from DHA supplementation. Lipidomic analyses suggest levels of arachidonic acid (ARA) and n-6 docosapentaenoic acid (DPA) containing phospholipid species were lower in the hippocampus of DHA supplemented compared with control animals, and principal component analyses revealed a potential dietary treatment effect for hippocampal PUFA. Females fed DHA had slightly more PE P-18:0_22:6 and maintained levels of PE 18:0_20:4 in the hippocampus in contrast with males fed DHA. Understanding how DHA supplementation during the perinatal and adolescent periods changes cognitive function in a sex-specific manner has important implications for determining the dietary requirements of DHA. This study adds to previous work highlighting the importance of DHA for spatial memory and provides evidence that further research needs to consider how DHA supplementation can cause sex-specific changes.

New perspectives on randomized controlled trials with omega-3 fatty acid supplements and cognition: A scoping review

Long chain polyunsaturated omega-3 fatty acids (n-3 FA), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are known to be important components in a healthy diet and contribute to healthy functioning of the heart and the brain, among other organs. Although there are epidemiological studies on the strong relationship between fish or n-3 FA consumption and lower risk of cognitive decline, results from randomized controlled trials (RCTs) are less consistent. Here, we performed a scoping review on RCTs with n-3 FA supplementation where cognition was evaluated. Seventy-eight RCTs published before April 2022 were included in this review. Among these RCTs, 43.6% reported a positive cognitive outcome after the consumption of n-3 FA compared to the placebo. However, there was a large diversity of populations studied (age ranges and health status), wide range of doses of EPA + DHA supplemented (79 mg/day - 5200 mg/day) and a multitude of tests evaluating cognition, mainly diagnostic tests, that were used to assess cognitive scores and overall cognitive status. RCTs were thereafter categorized into non-cognitively impaired middle-aged adults (n = 24), non-cognitively impaired older adults (n = 24), adults with subjective memory complaints (n = 14), adults with mild cognitive impairments (MCI, n = 9) and people with diagnosed dementia or other cognitive changes (n = 7). Among these categories, 66.7% of RCTs conducted with MCI adults reported a positive cognitive outcome when supplemented with n-3 FA vs. the placebo. Therefore, this scoping review provides rationale and questions to a) strengthen the design of future RCTs with n-3 FA for cognitive outcomes, and b) generate more informative data to support clinicians in their practice in assessing cognition before and after a nutritional intervention.

Docosahexaenoic acid production of the marine microalga Isochrysis galbana cultivated on renewable substrates from food processing waste under CO2 enrichment

Leftover dough is a starch-rich food processing waste of Chinese steamed bread. Leftover dough hydrolysates enriched with glucose and amino acids were used to cultivate the marine microalga Isochrysis galbana to produce docosahexaenoic acid (DHA) under CO₂ enrichment. Isochrysis galbana could use mixed carbon sources (CO₂, glucose, and amino acids) synchronously to grow and accumulate DHA. Cell growth, the uptake of glucose and amino acids, and DHA production were significantly affected by CO₂ enrichment. The maximum biomass concentration of 3.85 g L^-1 was achieved with 3 % CO₂. And the maximum DHA yield was 65.5 mg L^-1 d^-1. To enhance DHA production, a two-stage cultivation strategy was successfully developed by this work. The maximum DHA yield of the two-stage culture was elevated by 2.3-fold. It is feasible to produce DHA by Isochrysis galbana using leftover dough under CO₂ enrichment.

Gut microbiome and metabolome analyses reveal the protective effect of special high-docosahexaenoic acid tuna oil on d-galactose-induced aging in mice

Aging is closely related to altered gut function and its microbiome composition. To elucidate the mechanisms involved in the preventive effect of special high-docosahexaenoic acid tuna oil (HDTO) on senescence, the effects of different doses of HDTO on the gut microbiome and metabolome of d-galactose-induced aging mice were studied. Deferribacteres and Tenericutes and uridine might be used as indicator bacteria and characteristic metabolites to identify aging, respectively. HDTO markedly improved the impaired memory and antioxidant abilities induced by d-galactose. At the phylum level, the abundance of Firmicutes and Tenericutes was significantly increased upon d-galactose induction, while that of Bacteroidetes, Proteobacteria, and Deferribacteres was significantly decreased. At the genus level, the variation mainly presented as an increase in the abundance of the Firmicutes genera Ligilactobacillus, Lactobacillus, and Erysipelothrix, the decrease in the abundance of the Bacteroidetes genera Bacteroides and Alistipes, the Firmicutes genus Dielma, and the Deferribacteres genus Mucispirillum. HDTO supplementation reversed the alterations in the intestinal flora by promoting the proliferation of beneficial flora during the aging process; the metabolic pathways, such as glycine-serine-threonine metabolism, valine-leucine-isoleucine biosynthesis, and some metabolic pathways involved in uridine, were also partially restored. Furthermore, the correlation analysis illustrated an obvious correlation between gut microbiota, its metabolites, and aging-related indices. Moreover, it is worth noting that the metabolic regulation by dietary intervention varied with different HDTO doses and did not present a simple additive effect; indeed, each dose showed a unique modulation mechanism.

Docosahexaenoic Acid Alleviates Brain Damage by Promoting Mitophagy in Mice with Ischaemic Stroke

Mitophagy, the selective removal of damaged mitochondria through autophagy, is crucial for mitochondrial turnover and quality control. Docosahexaenoic acid (DHA), an essential omega-3 fatty acid, protects mitochondria in various diseases. This study aimed to investigate the neuroprotective role of DHA in ischaemic stroke models in vitro and in vivo and its involvement in mitophagy and mitochondrial dysfunction. A mouse model of ischaemic stroke was established through middle cerebral artery occlusion (MCAO). To simulate ischaemic stroke in vitro, PC12 cells were subjected to oxygen–glucose deprivation (OGD). Immunofluorescence analysis, western blotting (WB), electron microscopy (EM), functional behavioural tests, and Seahorse assay were used for analysis. DHA treatment significantly alleviated the brain infarction volume, neuronal apoptosis, and behavioural dysfunction in mice with ischaemic stroke. In addition, DHA enhanced mitophagy by significantly increasing the number of autophagosomes and LC3-positive mitochondria in neurons. The Seahorse assay revealed that DHA increased glutamate and succinate metabolism in neurons after ischaemic stroke. JC-1 and MitoSox staining, and evaluation of ATP levels indicated that DHA-induced mitophagy alleviated reactive oxygen species (ROS) accumulation and mitochondrial injury. Mechanistically, DHA improved mitochondrial dynamics by increasing the expression of dynamin-related protein 1 (Drp1), LC3, and the mitophagy clearance protein Pink1/Parkin. Mdivi-1, a specific mitophagy inhibitor, abrogated the neuroprotective effects of DHA, indicating that DHA protected neurons by enhancing mitophagy. Therefore, DHA can protect against neuronal apoptosis after stroke by clearing the damaged mitochondria through Pink1/Parkin-mediated mitophagy and by alleviating mitochondrial dysfunction.

Mixed Tree Nuts, Cognition, and Gut Microbiota: A 4-Week, Placebo-Controlled, Randomized Crossover Trial in Healthy Nonelderly Adults

BACKGROUND

Beneficial effects of nut supplementation on cognitive function have previously been demonstrated in young and older adults. Alterations to gut microbiota have also been shown following tree nut consumption. However, no data exists on the effects of nuts on cognition and intestinal microbial communities assessed within the same study.

OBJECTIVES

The study aimed to examine the effects of daily consumption of tree nuts for 4 wk on cognitive function (primary outcome), mood, metabolomics, and gut microbial species (secondary outcomes) in healthy, nonelderly adults.

METHODS

This randomized, placebo-controlled, double-blind, counterbalanced crossover study assessed the effects of 4 wk of supplementation with 30 g/d mixed tree nuts versus placebo on cognition and mood in 79 healthy adults aged 18-49 y. Metabolic responses, gut bacterial community structure, and the potential for these to impact cognition were explored using a multi-omic approach. Bacterial community analysis was conducted in Quantitative Insights Into Microbial Ecology 2 (QIIME2).

RESULTS

Mixed model analysis indicated that nut consumption led to significant improvements to accuracy (placebo M = 92.2% compared with NUTS M = 94.5%; P = 0.019) and speed of response (placebo M = 788 ms compared with NUTS M = 757 ms; P = 0.004) on a picture recognition task. No significant changes to bacterial community α or β diversity were observed when comparing nut consumption to the placebo arm. However, an unclassified Lachnospiraceae amplicon sequence variant (ASV) was significantly enriched in participants when supplemented with nuts (P = 0.015). No correlations were observed between the changes to picture recognition and the changes to the unclassified Lachnospiraceae ASV. There were no significant changes to the urinary metabolome.

CONCLUSIONS

These findings indicate a positive effect of nut on cognition following only 4 wk of consumption in a healthy nonelderly sample, as well as upregulation of a microbial taxa associated with gut health. The effects appear to be independent of one another, but further exploration is required in those experiencing cognitive decline and/or gut dysbiosis.

Gene-environment interactions in Alzheimer disease: the emerging role of epigenetics

With the exception of a few monogenic forms, Alzheimer disease (AD) has a complex aetiology that is likely to involve multiple susceptibility genes and environmental factors. The role of environmental factors is difficult to determine and, until a few years ago, the molecular mechanisms underlying gene-environment (G × E) interactions in AD were largely unknown. Here, we review evidence that has emerged over the past two decades to explain how environmental factors, such as diet, lifestyle, alcohol, smoking and pollutants, might interact with the human genome. In particular, we discuss how various environmental AD risk factors can induce epigenetic modifications of key AD-related genes and pathways and consider how epigenetic mechanisms could contribute to the effects of oxidative stress on AD onset. Studies on early-life exposures are helping to uncover critical time windows of sensitivity to epigenetic influences from environmental factors, thereby laying the foundations for future primary preventative approaches. We conclude that epigenetic modifications need to be considered when assessing G × E interactions in AD.

Personalized nutrition: A review of genotype-based nutritional supplementation

Nutritional disorders have become a major public health issue, requiring increased targeted approaches. Personalized nutrition adapted to individual needs has garnered dramatic attention as an effective way to improve nutritional balance and maintain health. With the rapidly evolving fields of genomics and nutrigenetics, accumulation of genetic variants has been indicated to alter the effects of nutritional supplementation, suggesting its indispensable role in the genotype-based personalized nutrition. Additionally, the metabolism of nutrients, such as lipids, especially omega-3 polyunsaturated fatty acids, glucose, vitamin A, folic acid, vitamin D, iron, and calcium could be effectively improved with related genetic variants. This review focuses on existing literatures linking critical genetic variants to the nutrient and the ways in which these variants influence the outcomes of certain nutritional supplementations. Although further studies are required in this direction, such evidence provides valuable insights for the guidance of appropriate interventions using genetic information, thus paving the way for the smooth transition of conventional generic approach to genotype-based personalized nutrition.

Dietary Intervention in Infancy and Cognitive Function in Young Adulthood: The Special Turku Coronary Risk Factor Intervention Project

OBJECTIVE

Consumption of saturated fatty acids (SAFAs), polyunsaturated fatty acids (PUFAs), cholesterol, and fiber have been linked with cognitive function in adults. We evaluated these associations from childhood by leveraging data from the Special Turku Coronary Risk Factor Intervention Project (STRIP).

STUDY DESIGN

STRIP recruited children aged 5 months and randomly assigned them into intervention/control groups. The intervention introduced a heart-healthy diet, characterized mainly by low consumption of SAFAs and cholesterol, through counseling at least biannually between age 7 months and 20 years. Diet was assessed repeatedly using food diaries. Six years after the end of the intervention phase, at age 26 years, the participants were invited to the first postintervention follow-up, which included cognitive testing that covered learning and memory, verbal memory, short-term working memory, reaction time, information processing, and cognitive flexibility and inhibitory control. We studied the associations of the STRIP intervention and the consumptions of SAFAs, PUFAs, cholesterol, and fiber within these cognitive domains.

RESULTS

Participants in the STRIP intervention group had better cognitive flexibility and inhibitory control and were better able to manage conflicting information and ignore task-irrelevant information (0.18 SD higher in the intervention group, adjusted for sex and socioeconomic status). No associations were observed with the dietary components studied.

CONCLUSIONS

The infancy-onset STRIP intervention, which promoted a heart-healthy diet, was favorably associated with cognitive flexibility and inhibitory control at age 26 years. No associations were found for the intervention targets studied, indicating that these specific dietary components did not underlie the observed effect of the intervention.

Long-chain Omega-3 fatty acids supplementation and cognitive performance throughout adulthood: A 6-month randomized controlled trial

OBJECTIVE

To investigate whether omega-3 polyunsaturated fatty acids (n-3 PUFA) supplementation improve cognitive performance and if apolipoprotein E (APOE) genotype or age were effect modifiers.

METHODS

Healthy adults of 20 to 80 years old (n = 193) were completed a 6-month double-blind randomized controlled trial with two groups: 2.5 g/day of n-3 PUFA or a placebo. Primary outcomes were visuospatial ability and working memory and secondary outcomes were episodic memory and executive function, measured at baseline and 6 months.

RESULTS

Cognitive performances did not significantly differ between groups on primary or secondary outcomes after 6 months of treatment. APOE carriers and age were not effect modifiers for any outcomes. Those with low episodic memory scores and taking the n-3 PUFA supplement, significantly improved their scores (p = 0.043).

CONCLUSIONS

A 6-month n-3 PUFA supplementation did not improve cognitive performance in cognitively healthy adults and APOE status or age were not effect modifiers.

Use of fish oil supplements is differently related to incidence of all-cause and vascular dementia among people with the distinct APOE ε4 dosage

BACKGROUNDS &AIMS

Previous studies have shown that marine omega-3 PUFAs (fish oil) supplements was associated with improved cognitive function, whereas the association between use of fish oil supplements and risk of incident dementia was still unclear. We aimed to prospectively assess the relations between use of fish oil supplements and risks of all-cause and disease-specific dementia according to the apolipoprotein E (APOE) ε4 dosage.

METHODS

A total of 445,961 participants from UK biobank, who were free of dementia at baseline and completed data on supplement use and genetic information were analyzed in this study. Cox proportional hazards models were used to calculate the hazard ratios (HRs) comparing incident dementia rates in participants who did and did not use fish oil.

RESULTS

During a median of 12.2 years of follow-up, a total of 5795 incident cases of dementia were documented, including 1266 cases of vascular dementia and 2382 cases of AD. After adjustment for covariates, use of fish oil supplements was significantly associated with lower risks of all-cause dementia (Hazard ratios, HR, 95% CI, 0.90, 0.85-0.96) and vascular dementia (HR, 0.85; 95% CI, 0.75-0.97), but not AD (HR, 0.99; 95% CI, 0.91-1.09). For all-cause dementia and vascular dementia, we found that the protective associations appeared to be attenuated by the increasing APOE ε4 dosage (P-interaction = 0.002 and 0.002, respectively). Notably, the use of fish oil supplements was significantly associated with an 86.0% higher risk of vascular dementia in participants with two APOE-ε4 alleles (HR, 1.86, 95%CI, 1.23-2.80).

CONCLUSIONS

Our results indicate that use of fish oil supplements is differently associated with risks of all-cause dementia and vascular dementia according to the APOE ε4 dosage.

Factors Influencing Alzheimer's Disease Risk: Whether and How They are Related to the APOE Genotype

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease featuring progressive cognitive impairment. Although the etiology of late-onset AD remains unclear, the close association of AD with apolipoprotein E (APOE), a gene that mainly regulates lipid metabolism, has been firmly established and may shed light on the exploration of AD pathogenesis and therapy. However, various confounding factors interfere with the APOE-related AD risk, raising questions about our comprehension of the clinical findings concerning APOE. In this review, we summarize the most debated factors interacting with the APOE genotype and AD pathogenesis, depict the extent to which these factors relate to APOE-dependent AD risk, and discuss the possible underlying mechanisms.

Changes in the level of fatty acids in the brain of rats during memory acquisition

Memory acquisition is accompanied by many cellular and molecular processes, and it is not always clear what role they play. Fatty acids (FAs) are known to be important for cognitive functions, but the details of their involvement in memory processes remain unknown. We investigated FAs in the prefrontal cortex and hippocampus of rats trained to perform a task with food reinforcement. The learning consisted of two training sessions, each of which included 10 trials. The results showed that such training altered individual FAs in the brains. The most significant changes were in the prefrontal cortex, where an increase in the level of many FAs occurred, especially after the second training session: palmitic (16:0), stearic (18:0), docosahexaenoic (22:6, n-3), arachidonic (22:4, n-6), docosapentaenoic (22:5, n-6) acids. Changes in the fatty acid level after training in rats were detected only in the left hippocampus, where the levels of palmitic, docosapentaenoic, and docosahexaenoic acids changed. The changes in the right hippocampus were not significant. In both the prefrontal cortex and the left hippocampus, 72 h after training, all FAs returned to control levels. We believe that the main role of a reversible increase in FA levels during memory acquisition is to support and protect cellular processes involved in memory acquisition. Consolidation of memory traces, which occurs mainly in the neocortex, requires protection from external influences, to which FAs makes a significant contribution. They are able to improve neuronal plasticity, enhance local blood flow, improve mitochondrial processes, and suppress pro-inflammatory signals.

Efficacy and Safety of Ashwagandha Root Extract on Cognitive Functions in Healthy, Stressed Adults: A Randomized, Double-Blind, Placebo-Controlled Study

Background

The global prevalence of stress is increasing. Stress adversely affects cognitive ability, sleep quality, and overall psychological well-being. Ashwagandha (Withania somnifera (L.) Dunal), an essential medicine in Ayurveda, is reportedly beneficial in reducing stress and improving memory. This double-blind, randomized, placebo-controlled clinical study evaluated the effect of Ashwagandha root extract sustained-release capsule 300 mg (Prolanza™; hereafter Ashwagandha SR) on cognitive functions, stress levels, sleep quality, overall well-being, and safety in stressed subjects.

Methods

Subjects (130 healthy cognitively sound adults [20–55 years, body mass index:18–29 kg/m²]) having a Perceived Stress Scale (PSS) score of 14–24 were randomized to receive either Ashwagandha SR or placebo. Subjects took one capsule of Ashwagandha SR or placebo daily for 90 consecutive days. This study was registered on Clinical Trials Registry-India (CTRI) on 13/11/2019 [number: CTRI/2019/11/021990]. The primary endpoint was the change in cognitive function as measured by CANTAB from baseline to the end of the study period (90 ± 7 days). The secondary outcomes included the change in PSS-10 score, serum cortisol level (9–11 am), the OHQ score, the PSQI, and serum BDNF levels.

Results

Only 125 completed the study and were evaluated. The Cambridge Neuropsychological Test Automated Battery (CANTAB) reported significantly improved recall memory, and the total error rate in recalling patterns significantly decreased at visit 4 in the Ashwagandha SR group vs. the placebo group (first attempt memory score:12.9 ± 6.7 vs. 10.1 ± 6.3; total errors:17.5 ± 23.3 vs. 27.7 ± 23.6). At visit 4, lower PSS-10 score (13.0 ± 5.0 vs. 18.7 ± 4.6; p < .0001), serum cortisol levels (p=0.0443), and Pittsburgh Sleep Quality Index (PSQI) score (p < .0001) but higher Oxford Happiness Questionnaire (OHQ) scores (p < .0001) were seen in Ashwagandha SR vs. the placebo group, suggesting significantly lower stress levels and significantly better psychological well-being and sleep quality in the former. No adverse events were reported.

Conclusions

This is the first clinical study assessing Ashwagandha SR for its safety and efficacy. Treatment with one Ashwagandha SR capsule once daily for 90 days improved memory and focus, psychological well-being, and sleep quality, reduced stress levels, and was safe and well-tolerated.

Biological Activity of Sacha Inchi (Plukenetia volubilis Linneo) and Potential Uses in Human Health: A Review

Sacha inchi (Plukenetia volubilis Linneo) is an ancestral plant originating in the Amazon jungle that has been adopted as a food source due to its high nutritional value, which has gradually been recognized to have potential benefits for human health. Diverse prospective studies have evaluated the effect of consuming components from the plant, derivatives from its seeds, leaves and shell on preventing the risk of cardiovascular disease, chronic inflammatory disease, dermatitis and controlling tumor proliferation, especially given its recognized high content of essential fatty acids, phenolic compounds and vitamin E, showing antioxidant, hypolipidemic, immunomodulation and emollient activity, as well as the capacity to remove heavy metals from aqueous solutions. This review offers a complete description of the existing information on the use and biological activity of P. volubilis L., based on its essential lipid components and evidenced on its use in the field of human health, in prevention, therapeutic and nutritional contexts, along with industrial uses, making it a promising bioresource.

A gene-environment interplay between omega-3 supplementation and APOE ε4 provides insights for Alzheimer's disease precise prevention amongst high-genetic-risk population

BACKGROUND AND PURPOSE

The present study aimed to explore whether and how omega-3 (ω-3) supplementation could interact with genetic factors to modulate cognitive functions, amyloid pathologies, and Alzheimer's disease (AD) risk.

METHODS

A total of 1,670 non-demented participants (mean age 73 years, 47% females, 41% APOE ε4 carriers) were followed up for 10 years. Hierarchical regressions, linear mixed-effects models, and Cox proportional hazards models were used to examine the interaction effects of ω-3 supplementation with APOE ε4 and polygenic hazard scores, after adjusting for age, gender, education, cognitive diagnosis, insomnia, depression, anxiety, and cardiovascular risk score.

RESULTS

Individuals who progress to AD during the follow-up tend to take a shorter duration of ω-3 at baseline than those stable, for whom the difference remained significant only amongst APOE ε4 carriers (p < 0.01). The interaction term (APOE ε4 × ω-3) accounted for a significant amount of variance in cognition and cerebral amyloid burden. Long-term ω-3 use protected cognition (especially memory function) and lowered amyloid burden and AD risk only amongst APOE ε4 carriers. Mediation analysis suggested that amyloid pathologies, brain reserve capacities, and brain metabolism mediated the relationships of ω-3 use with memory and global cognition for APOE ε4 (+) carriers. Similar interaction and mediation effects were also indicated amongst high-risk subjects defined by polygenic hazard scores.

CONCLUSIONS

Long-term ω-3 intake may have a role in AD prevention in genetically at-risk populations.

Fish, n-3 fatty acids, cognition and dementia risk: not just a fishy tale

With growing and ageing populations, the incidence of dementia is expected to triple globally by 2050. In the absence of effective drugs to treat or reverse the syndrome, dietary approaches which prevent or delay disease onset have considerable population health potential. Prospective epidemiological studies and mechanistic insight from experimental models strongly support a positive effect of a high fish and long chain n-3 fatty acid (EPA and DHA) intake on a range of cognitive outcomes and dementia risk, with effect sizes equivalent to several years of ageing between the highest and lowest consumers. As reviewed here, an effect of EPA and DHA on neuroinflammation and oxylipin production is likely to in part mediate the neurophysiological benefits. However, randomised controlled trials (RCTs) with EPA and DHA supplementation have produced mixed findings. Insight into the likely modulators of response to intervention and factors which should be considered for future RCTs are given. Furthermore, the impact of APOE genotype on disease risk and response to EPA and DHA supplementation is summarised. The prevalence of dementia is several-fold higher in APOE4 females (about 13% Caucasian populations) relative to the general population, who are emerging as a subgroup who may particularly benefit from DHA intervention, prior to the development of significant pathology.

Fish intake, n-3 fatty acid body status, and risk of cognitive decline: a systematic review and a dose-response meta-analysis of observational and experimental studies

CONTEXT

Randomized controlled trials (RCTs) testing supplementation with eicosapentaenoic (EPA) and docosahexaenoic (DHA) fatty acids have failed to provide evidence supporting a suggested inverse association between fish intake and dementia risk.

OBJECTIVE

Dose-response analyses were conducted to evaluate associations between fish intake, all-cause dementia or Alzheimer's Disease (AD), and the effect of EPA/DHA supplementation on cognitive performance.

DATA SOURCES

PubMed, Scopus and Web of Science databases were searched for original research evaluating either associations between fish intake and dementia or AD, or the impact of EPA and/or DHA supplementation on the risk of cognitive decline.

DATA EXTRACTION

Data were collected on study characteristics and methods; number of cases/deaths (for observational studies); categories of exposure; model covariates; risk estimates from the most-adjusted model; type and dosage of supplementation (from RCTs); fatty acid levels in blood; and differences in cognition test results before and after supplementation. Risk of bias was assessed through the ROBINS-E and RoB2.0 tools for observational and experimental studies, respectively.

DATA ANALYSIS

Weighted mixed-effects models were applied, allowing for the inclusion of studies with 2 levels of exposure. Based on findings with low/moderate risk of bias, fish intake of up to 2 portions (250 g) per week was associated with a 10% reduction (95% confidence interval [CI]: 0.79, 1.02, Ν = 5) in all-cause dementia and a 30% reduction (95% CI: 0.54, 0.89, Ν = 3) in AD risk. Changes in EPA and DHA body status had a positive impact on participants' executive functions, but not on their overall cognitive performance.

CONCLUSION

The protection offered by fish intake against cognitive decline levels off at intakes higher than 2 portions/week and likely relates to the impact of EPA and DHA on the individual's executive functions, although there remain questions about the mechanisms linking the short- and long-term effects.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42019139528.

Health benefits of docosahexaenoic acid and its bioavailability: A review

Docosahexaenoic acid (DHA) is the predominant omega-3 long-chain polyunsaturated fatty acid found in human brain and eyes. There are a number of studies in the literature showing the health benefits of DHA. It is critical throughout all life stages from the need for fetal development, the prevention of preterm birth, and the prevention of cardiovascular disease to the improvements in the cognitive function and the eye health of adults and elderly. These benefits might be related to the modulation of gut microbiota by DHA. In addition, there are some discrepancies in the literature regarding certain health benefits of DHA, and this review is intended to explore and understand these discrepancies. Besides the variations in the DHA contents of different supplement sources, bioavailability is crucial for the efficacy of DHA supplements, which depends on several factors. For example, DHA in phospholipid and triglyceride forms are more readily to be absorbed by the body than that in ethyl ester form. In addition, dietary lipids in meals and emulsification of DHA oil can increase the bioavailability of DHA. Estrogens stimulated the biosynthesis of DHA, whereas testosterone stimulus induced a decrease in DHA. The roles of DHA through human lifespan, the sources, and its recommended daily intake in different countries are also discussed to provide a better understanding of the importance of this review.

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

Context

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

Objective

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

Data Sources

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

Data Extraction

Data from eligible articles was extracted by 2 reviewers.

Data Analysis

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

Results

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

Conclusion

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

Systematic Review Registration

PROSPERO registration no. CRD42020153179.

Dietary Supplement Ingredients for Optimizing Cognitive Performance Among Healthy Adults: A Systematic Review

Background: Dietary supplements promoted for brain health and enhanced cognitive performance are widely available. Claims made for these products are directed not only to the elderly wishing to prevent or mitigate cognitive decline, but also young healthy populations looking to boost their cognitive performance. It is unclear whether these claims made on product bottles and through advertising match the science. Objectives: To explore the evidence on the efficacy and safety of single dietary supplement ingredients frequently marketed with claims of enhanced cognitive performance among healthy adults. Design: A systematic review. Results: Nine of 54 dietary supplement ingredients identified through a scoping review met the eligibility criteria with at least 3 published studies identified per ingredient, yielding 69 unique publications. Ingredients evaluated included Bacopa monnieri, choline, creatine, omega-3 fatty acids, Ginkgo biloba, ginseng, Rhodiola rosea, tyrosine, and valerian root, all in supplement form and compared with a placebo, at various serving sizes and durations of use. Conclusions: The low level of certainty in the state of the science, coupled with not always knowing what is in a dietary supplement product, make weighing risks and benefits difficult; these data hinder the ability to develop recommendations about using such ingredients for consumers interested in boosting their cognitive performance. Whereas certain trends regarding promising serving sizes or duration for use, are pointed to in this synthesis, when combined, studies are inconsistent and imprecise, and many are methodologically flawed. Potential solutions to address research gaps are offered, for future research next steps, which is needed to strengthen the evidence and inform decisions.

APOE Genotype and Alzheimer's Disease: The Influence of Lifestyle and Environmental Factors

Alzheimer's disease (AD) is the most common neurodegenerative disorder with obscure pathogenesis and no disease-modifying therapy to date. AD is multifactorial disease that develops from the complex interplay of genetic factors and environmental exposures. The E4 allele of the gene encoding apolipoprotein E (APOE) is the most common genetic risk factor for AD, whereas the E2 allele acts in a protective manner. A growing amount of epidemiological evidence suggests that several lifestyle habits and environmental factors may interact with APOE alleles to synergistically affect the risk of AD development. Among them, physical exercise, dietary habits including fat intake and ketogenic diet, higher education, traumatic brain injury, cigarette smoking, coffee consumption, alcohol intake, and exposure to pesticides and sunlight have gained increasing attention. Although the current evidence is inconsistent, it seems that younger APOE4 carriers in preclinical stages may benefit mostly from preventive lifestyle interventions, whereas older APOE4 noncarriers with dementia may show the most pronounced effects. The large discrepancies between the epidemiological studies may be attributed to differences in the sample sizes, the demographic characteristics of the participants, including age and sex, the methodological design, and potential related exposures and comorbidities as possible cofounding factors. In this Review, we aim to discuss available evidence of the prominent APOE genotype-environment interactions in regard to cognitive decline with a focus on AD, providing an overview of the current landscape in this field and suggesting future directions.

An Analysis of Oxidative Changes and the Fatty Acid Profile in Stored Poultry Sausages with Liquid and Microencapsulated Fish Oil Additives

This study deals with the fatty acid profile and oxidative changes (TBARS) in vacuum-packed (VP) or modified-atmosphere-packed (MAP) finely-comminuted poultry sausages with liquid fish oil and microencapsulated fish oil (MC) additives. An analysis of omega-3 fatty acids (EPA and DHA) showed that their content in the samples with the fish oil additive decreased from the initial value of 0.22 g∙100 g⁻¹ of the product to 0.18 g∙100 g⁻¹ (MAP) and 0.17 g∙100 g⁻¹ (VP), respectively. After in vitro digestion, the total EPA and DHA content in the sample with microencapsulated oil amounted to 0.17 g∙100 g⁻¹ of the product. The TBARS values showed the VP samples with both forms of the fish oil additive had the lowest values on the first day of storage. Storage of the samples for 21 days caused a slight increase in the degree of lipid oxidation. The research indicated that the forms of the oil additive did not have a negative influence on the sensory features or the physicochemical properties of the sausages. The EPA and DHA levels in samples with liquid fish oil and those with oil microcapsules were sufficient for the sausage producer to declare high content of these fatty acids in accordance with the current EC regulation.

Evaluation of Omega-3 Status in Professional Basketball Players

ABSTRACT

Davis, JK, Freese, EC, Wolfe, AS, Basham, SA, and Stein, KMW. Evaluation of omega-3 status in professional basketball players. J Strength Cond Res 35(7): 1794-1799, 2021-Omega-3 polyunsaturated fatty acids (PUFA) has been shown to promote muscle remodeling, improve immune status, decrease muscle soreness, and help maintain explosive power. Research that has assessed omega-3 blood concentrations with athletes has primarily focused on the college athlete. However, limited work has been conducted with the professional athlete. Therefore, the purpose of this study was to evaluate the omega-3 PUFA blood concentrations, dietary, and supplement intake of professional basketball players. Blood collection occurred during preseason medical screenings and analyzed for eicosapentaenoic acid, docosahexaenoic acid, the omega-3 Index (O3i), and various fatty acids using dried blood spot sampling. The mean O3i of 119 professional basketball players was 5.02 + 1.19% (range, 2.84-9.76%). Dietary intake of players showed that 31% of players reported consuming no fish in their diet per week, with 61% of players reported consuming less than 2 servings of fish per week. Only 12 of the 119 players reported supplementing with omega-3 PUFA, which varied widely for dosage and frequency of supplementation. A moderate correlation was shown for O3i and dietary fish consumption per week (r = 0.58; p < 0.01) and fish consumption per month (r = 0.57; p < 0.01). A large number of players reported consuming less than the recommend amount of dietary fish per week and very few players reported supplementing with omega-3 PUFA. The low intake of omega-3 PUFA likely contributed, in part, to the majority of players having an O3i of less than 8%.

Case-cohort study of plasma phospholipid fatty acid profiles, cognitive function, and risk of dementia: a secondary analysis in the Ginkgo Evaluation of Memory Study

BACKGROUND

Phospholipids are biomarkers of dietary fat intake and metabolism, linked to several cardiometabolic disorders. Few prospective studies have assessed plasma phospholipids in relation to dementia risk and cognitive function.

OBJECTIVES

We aimed to evaluate the association between a decrease in linoleic acid accompanied with an increase in other fatty acids and cognitive function and dementia risk.

METHODS

We conducted a case-cohort study nested within the Ginkgo Evaluation of Memory Study. We included 1252 participants, 498 of whom who developed dementia during a mean of 5 y of follow-up. We measured 45 individual plasma phospholipids (as a percentage of total plasma phospholipid fatty acids) by GC and related these to Modified Mini-Mental State Examination (3MSE) scores at baseline and neurologist-adjudicated incidence of all-cause dementia and Alzheimer disease (AD), adjusting for sociodemographic and clinical characteristics.

RESULTS

Substitution of 1% of SFAs for 1% of linoleic acid, the predominant polyunsaturated n-6 (ɷ-6) fatty acid, was associated with higher risk of dementia (HR per 1% of SFAs instead of linoleic acid = 1.03; 95% CI: 1.00, 1.07) and a 0.08 point lower 3MSE score at baseline (95% CI: -0.12, -0.03), signifying worse cognitive function. When compared with linoleic acid, we found no associations of total monounsaturated, n-3 polyunsaturated, or trans fatty acids with risk of dementia or AD. However, the substitution of 1% of the marine n-3 PUFA DHA for linoleic acid was associated with lower risk of dementia (HR = 0.86 per 1% of DHA instead of linoleic acid; 95% CI: 0.76, 0.96). These associations were not modified by apolipoprotein E genotype, mild cognitive impairment at baseline, age, or sex.

CONCLUSIONS

Specific elements of diet may be associated with late-life dementia, a hypothesis that requires formal testing in randomized controlled trials and that represents a possible preventive intervention.

Supplementation with oil rich in eicosapentaenoic acid, but not in docosahexaenoic acid, improves global cognitive function in healthy, young adults: results from randomized controlled trials

BACKGROUND

Evidence regarding the effects of the omega-3 (ɷ-3) PUFAs (n-3 PUFAs) DHA and EPA on cognition is lacking.

OBJECTIVES

We investigated whether supplementation with oils rich in EPA or DHA improves cognition, prefrontal cortex (PFC) hemoglobin (Hb) oxygenation, and memory consolidation.

METHODS

Healthy adults (n = 310; age range: 25-49 y) completed a 26-wk randomized controlled trial in which they consumed either 900 mg DHA/d and 270 mg EPA/d (DHA-rich oil), 360 mg DHA/d and 900 mg EPA/d (EPA-rich oil), or 3000 mg/d refined olive oil (placebo). Cognitive performance and memory consolidation were assessed via computerized cognitive test battery. PFC Hb oxygenation was measured using near infrared spectroscopy (NIRS).

RESULTS

Both global accuracy and speed improved with EPA-rich oil compared with placebo and DHA-rich oil [EPA vs. placebo accuracy: estimated marginal mean (EMM) = 0.17 (95% CI: 0.09, 0.24) vs. EMM = 0.03 (95% CI = -0.04, 0.11); P = 0.044; EPA vs. placebo speed: EMM = -0.15 (95% CI: -0.22, -0.07) vs. EMM = 0.03 (95% CI: -0.05, 0.10); P = 0.003]. Accuracy of memory was improved with EPA compared with DHA [EMM = 0.66 (95% CI: 0.26, 1.06) vs. EMM = -0.08 (95% CI: -0.49, 0.33); P = 0.034]. Both EPA- and DHA-rich oils showed trends towards reduced PFC oxygenated Hb (oxy-Hb) compared with placebo [placebo: EMM = 27.36 µM (95% CI: 25.73, 28.98); DHA: EMM = 24.62 µM (95% CI: 22.75, 26.48); P = 0.060; EPA: EMM = 24.97 µM (95% CI: 23.35, 26.59); P = 0.082].

CONCLUSIONS

EPA supplementation improved global cognitive function and was superior to the oil enriched with DHA. Interpreted within a neural efficiency framework, reduced PFC oxygenated Hb suggests that n-3 PUFAs may be associated with increased efficiency.These trials were registered in the clinical trials registry (https://clinicaltrials.gov/) as NCT03158545, NCT03592251, NCT02763514.

Effects of Chewing Gum on Nitric Oxide Metabolism, Markers of Cardiovascular Health and Neurocognitive Performance after a Nitrate-Rich Meal

OBJECTIVES

Cardiovascular and neurocognitive responses to chewing gum have been reported, but the mechanisms are not well understood. Chewing gum after a nitrate-rich meal may upregulate the reduction of oral nitrate to nitrite and increase nitric oxide (NO), a molecule important to cardiovascular and neurocognitive health. We aimed to explore effects of chewing gum after a nitrate-rich meal on nitrate metabolism (through the enterosalivary nitrate-nitrite-NO pathway), endothelial function, blood pressure (BP), neurocognitive performance, mood and anxiety.

METHODS

Twenty healthy men (n = 6) and women (n = 14) with a mean age of 48 years (range: 23-69) were recruited to a randomized controlled cross-over trial. After consumption of a nitrate-rich meal (180 mg of nitrate), we assessed the acute effects of chewing gum, compared to no gum chewing, on (i) salivary nitrate, nitrite and the nitrate reductase ratio (100 x [nitrite]/([nitrate] + [nitrite]); (ii) plasma nitrite, S-nitrosothiols and other nitroso species (RXNO); (iii) endothelial function (measured by flow mediated dilatation); (iv) BP; (v) neurocognitive performance; (vi) mood; and (vii) anxiety.

RESULTS

Consumption of the nitrate-rich meal resulted in a significant increase in markers of nitrate metabolism. A significantly higher peak flow mediated dilatation was observed with chewing compared to no chewing (baseline adjusted mean difference: 1.10%, 95% CI: 0.06, 2.14; p = 0.038) after the nitrate-rich meal. A significant small increase in systolic BP, diastolic BP and heart rate were observed with chewing compared to no chewing after the nitrate-rich meal. The study did not observe increased oral reduction of nitrate to nitrite and NO, or improvements in neurocognitive performance, mood or anxiety with chewing compared to no chewing.

CONCLUSION

Chewing gum after a nitrate-rich meal resulted in an acute improvement in endothelial function and a small increase in BP but did not result in acute effects on neurocognitive function, mood or anxiety.

Longitudinal investigation of the relationship between omega-3 polyunsaturated fatty acids and neuropsychological functioning in recent-onset psychosis: A randomized clinical trial

Alterations in polyunsaturated fatty acids (PUFAs), including omega-3 and omega-6, have been implicated in the pathophysiology of psychotic disorders, but little is known about their associations with neuropsychological functioning. The present study includes 46 recent-onset psychosis patients who participated in a larger (n = 50) double blind, placebo-controlled randomized clinical trial comparing 16 weeks of treatment with either risperidone + fish oil (FO) (EPA 740 mg and DHA 400 mg daily) or risperidone + placebo and completed neuropsychological assessments at the baseline timepoint. We investigated the relationship between baseline omega-3 (i.e., eicosapentaenoic acid, EPA; docosapentaenoic acid, DPA and docosahexaenoic acid, DHA) and omega-6 (i.e., arachidonic acid, AA) PUFA with baseline MATRICS Consensus Cognitive Battery (MCCB) and Brief Psychiatric Rating Scale (BPRS) scores. Twenty-five patients had neuropsychological data available at 16 weeks following participation in the clinical trial, which included 12 patients assigned to risperidone + FO and 13 patients assigned to risperidone + placebo. At baseline both higher DHA and EPA correlated significantly with better social cognition after controlling for functioning on other neuropsychological domains, total BPRS score, AA level and substance use. Also, at baseline higher AA correlated significantly with hostility/uncooperativeness after controlling for DHA + EPA + DPA, overall neuropsychological functioning and substance use. Patients treated with risperidone + FO demonstrated a significant longitudinal increase in social cognition that was significantly higher at 16 weeks compared to patients treated with risperidone + placebo. DHA also correlated significantly with social cognition at the 16-week timepoint. This study provides novel evidence for a differential role of omega-3 vs. omega-6 PUFA in neuropsychological deficits and symptoms in recent-onset psychosis and its treatment.

A Scoping Review of Dietary Factors Conferring Risk or Protection for Cognitive Decline in APOE ε4 Carriers

Alzheimer's disease (AD) is a progressive and fatal neurodegenerative disease. The strongest genetic risk factor for sporadic AD is carriage of the ε4 allele of the Apolipoprotein E (APOE) gene. Strategies to slow the progression of AD, including dietary interventions, may be modified by the pathogenic effect of this polymorphism. Our objective in this review was to determine the extent and quality of the literature investigating how dietary factors and interventions interact with the APOE ε4 genotype to impact cognitive decline in AD. To that end, we performed a systematic scoping review of published English-language articles involving human subjects. We found evidence suggesting that adherence to a Mediterranean diet may reduce cognitive decline among APOE ε4 carriers, whereas ketogenic agents appear to be ineffective. Diets high in saturated fats may be particularly harmful for APOE ε4 carriers. We identified several topics, including the use of ω-3 fatty acid and antioxidant supplements, for which additional high level evidence is needed.

Walnuts, Long-Chain Polyunsaturated Fatty Acids, and Adolescent Brain Development: Protocol for the Walnuts Smart Snack Dietary Intervention Trial

Background: Adolescence, when the most complex behaviors are refined to adult sophistication, represents a major window of opportunity and vulnerability for neuropsychological development. To support and protect this complex and active brain growth, different nutritional components considered essential need to be acquired from the diet. For instance, omega-3 fatty acids are mainly obtained from seafood, seeds, and walnuts. Known for their rich lipid profile, walnuts contain sizable amounts of an essential fatty acid, alpha-linolenic acid (ALA), the vegetable omega-3 fatty acid that is the precursor of two longer-chain omega-3 polyunsaturated fatty acids (omega-3 PUFA): docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids. While there is growing evidence of neuropsychological improvements in the young developing brain associated with omega-3 PUFA intake, few studies have examined whether consuming walnuts during adolescence entails similar beneficial effects. There is a need to further explore the ways in which walnuts influence youthful brain function, particularly for the long-term. Thus, we designed the WALNUTs study (WSS), a population-based randomized controlled trial conducted in adolescents in Barcelona, Spain. We hypothesize that walnut intake will increase omega-3 PUFA tissue availability (particularly ALA) to a level that enhances the neuropsychological development during adolescence. Methodology/Design: We conducted a 6-month population-based randomized controlled trial in teenagers (n = 800) and we aimed to determine the effectiveness of the intervention (four walnuts per day, or 30 kernel g, ~1.5g of ALA) in enhancing brain neuropsychological and socio-emotional development compared to a control group with no walnut intervention. Before randomization, different neuropsychological tests were recorded for all participants, and blood samples (in a subsample of participants) were collected to measure omega-3 PUFA levels at baseline, and all again, after randomization and the intervention. The data is now collected and we will conduct linear regression models to assess the effect of the intervention. Discussion: The WALNUTs (WSS) study results will allow us to better understand the role of plant-based omega-3 PUFA intake from regular walnut consumption on neuropsychological development during adolescence. Results could be translated into nutritional public health recommendations targeting teenagers. Trial Registration: ClinicalTrials.gov, U.S. National Library of Medicine, National Institutes of Health # NCT02590848. Retrospectively registered 29/10/2015.

Dietary fish hydrolysate supplementation containing n-3 LC-PUFAs and peptides prevents short-term memory and stress response deficits in aged mice

Brain aging is characterized by a decline in cognitive functions, which can lead to the development of neurodegenerative pathologies. Age-related spatial learning and memory deficits are associated with a chronic low-grade inflammation. Anxiety disorders and stress response alterations, occurring for a part of the elderly, have also been linked to an increased neuroinflammation and thus, an accelerated cognitive decline. Nutrition is an innovative strategy to prevent age-related cognitive impairments. Among the nutrients, n-3 long chain polyunsaturated fatty acids (LC-PUFAs) and low molecular weight peptides from proteins, especially those from marine resources, are good candidates for their immunomodulatory, anxiolytic and neuroprotective properties. The aim of this study is to determine the combined effect of n-3 LC-PUFAs and low molecular weight peptides on cognitive functions, and their mechanism of action. We are the first to show that a dietary supplementation with a fish hydrolysate containing n-3 LC-PUFAs and low molecular weight peptides prevented the age-related spatial short-term memory deficits and modulated navigation strategies adopted during spatial learning. In addition, the fish hydrolysate displayed anxiolytic activities with the reduction of anxiety-like behaviour in aged mice, restored the plasmatic corticosterone levels similar to adult animals following an acute stress and modulated the hypothalamic stress response. These effects on behaviour can be explained by the immunomodulatory and neuroprotective properties of the fish hydrolysate that limited microgliosis in vivo, decreased LPS-induced expression of pro-inflammatory cytokines and increased the expression of growth factors such as BDNF and NGF in vitro. Thus, n-3 LC-PUFAs and low molecular weight peptides contained in the fish hydrolysate can play an important role in the limitation of neuroinflammation and stress response alterations during aging and represent a potential strategy for the prevention of age-related cognitive decline.

CD36 in Alzheimer's Disease: An Overview of Molecular Mechanisms and Therapeutic Targeting

CD36 is a membrane protein with wide distribution in the human body, is enriched in the monocyte-macrophage system and endothelial cells, and is involved in the cellular uptake of long chain fatty acids (LCFA) and oxidized low-density lipoproteins. It is also a scavenger receptor, binding hydrophobic amyloid fibrils found in the Alzheimer's disease (AD) brain. In neurobiology research, it has been mostly studied in relationship with chronic ischemia and stroke, but it was also related to amyloid clearance by microglial phagocytosis. In AD animal models, amyloid binding to CD36 has been consistently correlated with a pro-inflammatory response. Therapeutic approaches have two main focuses: CD36 blockade with monoclonal antibodies or small molecules, which is beneficial in terms of the inflammatory milieu, and upregulation of CD36 for increased amyloid clearance. The balance of the two approaches, centered on microglia, is poorly understood. Furthermore, CD36 evaluation in AD clinical studies is still at a very early stage and there is a gap in the knowledge regarding the impact of LCFA on AD progression and CD36 expression and genetic phenotype. This review summarizes the role played by CD36 in the pathogenic amyloid cascade and explore the translatability of preclinical data towards clinical research.