The omega-6/omega-3 ratio and dementia or cognitive decline: a systematic review on human studies and biological evidence

Omega-3 polyunsaturated fatty acids in the brain and visual system: Focus on invertebrates

A critical role of omega-3 polyunsaturated fatty acids (PUFA), mainly docosahexaenoic acid 22:6ω3 (DHA), in the development and function of the brain and visual system is well established. DHA, the most abundant omega-3 PUFA in the vertebrate brain, contributes to neuro- and synaptogenesis, neuronal differentiation, synaptic transmission and plasticity, neuronal network formation, memory and behaviour formation. Based on these data, the unique importance of DHA and its irreplaceability in neural and retinal tissues has been postulated. In this review, we consider omega-3 PUFA composition in the brain and retina of various invertebrates, and show that DHA has only been found in marine mollusks and crustaceans. A gradual decrease in the DHA content until its disappearance can be observed in the brain lipids of the series marine-freshwater-terrestrial crustaceans and marine-terrestrial mollusks, suggesting that the transition to the land lifestyle in the evolution of invertebrates, but not vertebrates, was accompanied by a loss of DHA. As with terrestrial crustaceans and mollusks, DHA was not found in insects, either terrestrial or aquatic, or in nematodes. We show that the nervous and visual systems of various DHA-free invertebrates can be highly enriched in alpha-linolenic acid 18:3ω3 or eicosapentaenoic acid 20:5ω3, which affect neurological and visual function, stimulating synaptogenesis, synaptic transmission, visual processing, learning and even cognition. The review data show that, in animals at different levels of organization, omega-3 PUFA are required for the functioning of the nervous and visual systems and that their specific needs can be met by various omega-3 PUFA.

Nutritional management and autism spectrum disorder: A systematic review

BACKGROUND

Autism spectrum disorder (ASD) presents unique challenges related to feeding and nutritional management. Children with ASD often experience feeding difficulties, including food selectivity, refusal, and gastrointestinal issues. Various interventions have been explored to address these challenges, including dietary modifications, vitamin supplementation, feeding therapy, and behavioral interventions.

AIM

To provide a comprehensive overview of the current evidence on nutritional management in ASD. We examine the effectiveness of dietary interventions, vitamin supplements, feeding therapy, behavioral interventions, and mealtime practices in addressing the feeding challenges and nutritional needs of children with ASD.

METHODS

We systematically searched relevant literature up to June 2024, using databases such as PubMed, PsycINFO, and Scopus. Studies were included if they investigated dietary interventions, nutritional supplements, or behavioral strategies to improve feeding behaviors in children with ASD. We assessed the quality of the studies and synthesized findings on the impact of various interventions on feeding difficulties and nutritional outcomes. Data extraction focused on intervention types, study designs, participant characteristics, outcomes measured, and intervention effectiveness.

RESULTS

The review identified 316 studies that met the inclusion criteria. The evidence indicates that while dietary interventions and nutritional supplements may offer benefits in managing specific symptoms or deficiencies, the effectiveness of these approaches varies. Feeding therapy and behavioral interventions, including gradual exposure and positive reinforcement, promise to improve food acceptance and mealtime behaviors. The findings also highlight the importance of creating supportive mealtime environments tailored to the sensory and behavioral needs of children with ASD.

CONCLUSION

Nutritional management for children with ASD requires a multifaceted approach that includes dietary modifications, supplementation, feeding therapy, and behavioral strategies. The review underscores the need for personalized interventions and further research to refine treatment protocols and improve outcomes. Collaborative efforts among healthcare providers, educators, and families are essential to optimize this population's nutritional health and feeding practices. Enhancing our understanding of intervention sustainability and long-term outcomes is essential for optimizing care and improving the quality of life for children with ASD and their families.

New Insights on the Effects of Krill Oil Supplementation, a High-Fat Diet, and Aging on Hippocampal-Dependent Memory, Neuroinflammation, Synaptic Density, and Neurogenesis

Krill oil (KO) has been described as having the potential to ameliorate the detrimental consequences of a high-fat diet (HFD) on the aging brain, though the magnitude and mechanism of this benefit is unclear. We thus hypothesized that dietary KO supplementation could counteract the effects of cognitive aging and an HFD on spatial learning, neuroinflammation, neurogenesis, and synaptic density in the cortex and hippocampus of aged rats. Sixteen-month-old Sprague Dawley rats were fed for 12 weeks while being divided into four groups: control (CON); control with KO supplementation (CONKO); high-fat diet (HF); and high-fat diet with KO supplementation (HFKO). We measured food consumption, body mass, spatial memory (Morris water maze), microglia, neurogenesis, cytokine concentrations, and synaptic markers (post-synaptic density-95 and synaptophysin). Predictably, an HFD did induce significant differences in body weights, with the high-fat groups gaining more weight than the low-fat controls. However, KO supplementation did not produce significant changes in the other quantified parameters. Our results demonstrate that the dietary KO dose provided in the current study does not benefit hippocampal or cortical functions in an aging model. Our results provide a benchmark for future dosing protocols that may eventually prove to be beneficial.

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

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

Exploring the role of polyunsaturated fatty acid ratios in modulating neuroinflammation in LPS-induced microglia: A comprehensive in vitro analysis

The study investigated the effect of different omega (ω)- 3 and omega (ω)- 6 polyunsaturated fatty acid (PUFA) ratios on cytokine secretion, cell viability, and microglial cell shape in lipopolysaccharide (LPS)-induced microglia. The addition of PUFAs at different ratios, especially ω-3 and ratios of 7/1 and 2/1 ω-6/ω-3, resulted in a significant increase in the ameboid form of microglial cells, as well as more branching of their distal branches. Microglial cells were treated with varying ratios of PUFAs, and their cytokine secretion was measured. The results showed that all PUFA ratios had lower tumor necrosis factor (TNF)-α secretion than the control group, higher interleukin (IL)- 4 secretion in the ω-6 group, and less IL-10 secretion most down IL-6 secretion in the 7/1 ratio group. The study suggests that determining the appropriate ω-6/ω-3 consumption ratio, especially the 7/1 and 2/1 ratios, may help manage neuroinflammation, develop dietary models in immune-mediated neurodegenerative diseases, and open up new treatment possibilities.

Potentiality Assessment of the Acetylcholinesterase-Inhibitory Activity of Olive Oil with an Additive Edible Insect Powder

Edible insects (Alphitobius diaperinus Panzer, Gryllus campestris, Tenebrio molitor, Chorthippus biguttulus) are rich in nutrients that potentially inhibit acetylcholinesterase (AChE), but also improve cognition. The aim of this study was to evaluate four varied species of freeze-dried edible insects (purchased from a store); their nutrient composition, including fat, total phenolic compounds, vitamins, and antioxidant properties; and the potential inhibitory effect of AChE. An additional goal was to obtain olive oil with the addition of edible insects. Such oil was characterized by high oxidizing properties and showed high affinity to AChE. The results showed that mealworms and grasshoppers had the highest content of fats (PUFA/SFA) and phenolic compounds. These insects also showed a high content of vitamins, which correlated with the highest affinity for AChE. Therefore, they were added as a functional additive to olive oil. Olive oil with the addition of edible insects showed a higher affinity for AChE and enriched the olive oil with vitamin C and B vitamins.

Potential roles of polyunsaturated fatty acid-enriched diets in modulating social stress-like features

Fish oil or its major constituents, namely omega-3 poly-unsaturated fatty acid (n3-PUFA), are popular supplements to improve neurogenesis, neuroprotection, and overall brain functions. Our objective was to probe the implications of fat enriched diet with variable PUFAs supplements in ameliorating social stress (SS). We fed mice on either of the three diet types, namely the n-3 PUFA-enriched diet (ERD, n3:n6= 7:1), a balanced diet (BLD, n3:n6= 1:1) or a standard lab diet (STD, n3:n6= 1:6). With respect to the gross fat contents, the customized special diets, namely ERD and BLD were extreme diet, not reflecting the typical human dietary composition. Aggressor-exposed SS (Agg-E SS) model triggered behavioral deficiencies that lingered for 6 weeks (6w) post-stress in mice on STD. ERD and BLD elevated bodyweights but potentially helped in building the behavioral resilience to SS. STD adversely affected the gene networks of brain transcriptomics associated with the cell mortality, energy homeostasis and neurodevelopment disorder. Diverging from the ERD's influences on these networks, BLD showed potential long-term benefits in combatting Agg-E SS. The gene networks linked to cell mortality and energy homeostasis, and their subfamilies, such as cerebral disorder and obesity remained at the baseline level of Agg-E SS mice on BLD 6w post-stress. Moreover, neurodevelopment disorder network and its subfamilies like behavioral deficits remained inhibited in the cohort fed on BLD 6w post Agg-E SS.

A Comprehensive Investigation of the Potential Role of Lipoproteins and Metabolite Profile as Biomarkers of Alzheimer's Disease Compared to the Known CSF Biomarkers

Introduction

While cerebrospinal fluid (CSF) core biomarkers have been considered diagnostic biomarkers for a long time, special attention has been recently dedicated to lipoproteins and metabolites that could be potentially associated with Alzheimer's disease (AD) neurodegeneration. Herein, we aimed to investigate the relationship between the levels of CSF core biomarkers including Aβ-42, TAU, and P-TAU and plasma lipoproteins and metabolites of patients with AD from the baseline cohort of the Alzheimer's Disease Neuroimaging Initiative (ADNI) database.

Method

Using the ADNI database, fourteen subclasses of lipoproteins as well as a number of lipids and fatty acids and low-molecular metabolites including amino acids, ketone bodies, and glycolysis-related metabolites in blood samples were measured as potential noninvasive markers, and their association with the CSF core biomarkers was statistically investigated controlling for age and gender.

Results

A total number of 251 AD subjects were included, among whom 71 subjects were negative for the Apo-E ε4 allele and 150 were positive. There was no significant difference between the two groups regarding cognitive assessments, CSF core biomarkers, and lipoproteins and metabolites except the level of Aβ-42 (p < 0.001) and phenylalanine (p = 0.049), which were higher in the negative group. CSF TAU and P-TAU were significantly correlated with medium and small HDL in the negative group, and with extremely large VLDL in the positive group. Our results also indicated significant correlations of metabolites including unsaturated fatty acids, glycerol, and leucine with CSF core biomarkers.

Conclusion

Based on our findings, a number of lipoproteins and metabolites were associated with CSF core biomarkers of AD. These correlations showed some differences in Apo-E ε4 positive and negative groups, which reminds the role of Apo-E gene status in the pathophysiology of AD development. However, further research is warranted to explore the exact association of lipoproteins and other metabolites with AD core biomarkers and pathology.

Maternal stress in the postpartum period is associated with altered human milk fatty acid composition

BACKGROUND & AIMS

Maternal stress in the postpartum period affects not only the mother, but also her newborn child who is at increased risk for a wide range of disorders later in life. The mechanisms underlying transmission of maternal stress to the child remain elusive. Human milk (HM) is a potential candidate and is an important source of fatty acid (FA), which are crucial for child (neuro)development. This study aims to investigate whether maternal psychological and biological stress influences HM FA composition over the first month postpartum.

METHODS

The Amsterdam Mother's Milk study is a prospective cohort study. We included lactating women who delivered at term with a large range of stress levels: a high stress (HS) group, women whose child was hospitalized for a minimum of 2 days (n=23) and a control (CTL) group, women who gave birth to a healthy child (n=73). HM was collected three times a day at postpartum days 10, 17 and 24. Perceived psychological stress was measured using multiple validated questionnaires, while biological stress measures were based on cortisol in hair, saliva and HM. HM FAs were analyzed by gas-chromatography and compared between groups.

RESULTS

Maternal perceived stress scores were significantly higher in the HS group (p < 0.01), whereas cortisol measurements did not differ between groups. The absolute concentrations of total FA in HM (p=0.023), including the total amount of poly unsaturated fatty acids (PUFAs) (p=0.022) and omega-6 PUFAs (p=0.018), were lower in the HS group compared to the CTL group. Relative values of FAs did not differ between groups.

CONCLUSION

Maternal stress in the first month postpartum was associated with overall lower levels of FA in HM. This possibly indicates a route of transmission of maternal stress signals to the infant. Future research should investigate if these stress-induced changes in HM FAs have consequences for child development.

Ad libitum consumption of milk supplemented with omega 3, 6, and 9 oils from infancy to middle age alters behavioral and oxidative outcomes in male mice

We tested the hypothesis that administration of omega (ω)-9, ω-3, and ω-6 to mice can prevent oxidative alterations responsible for behavioral and cognitive alterations related with aging. Twenty-eight-day-old mice received skim milk (SM group), SM enriched with omega oil mixture (EM group), or water (control group) for 10 and 14 months, equivalent to middle age. Mice were evaluated for behavioral alterations related to depression and memory and oxidative status [brain levels of thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), and myeloperoxidase (MPO)]. The 10-month EM group increased immobility time during the forced swimming test compared with control, indicating increased stress response. The 14-month SM- and EM-treated groups increased sucrose consumption compared with control, showing an expanded motivational state. The 14-month SM group decreased the number of rearings compared with the 14-month control and EM groups. The number of entries and time spent in the central square of the open field was higher in the 10-month EM group than in the control, revealing an anxiolytic-like behavior. TBARS decreased in the hippocampus and striatum of the 10-month EM group compared with the control. A similar decrease was observed in the striatum of the 10-month SM group. GSH levels were higher in all 14-month treated groups compared with 10-month groups. MPO activity was higher in the 14-month EM group compared with the 14-month control and SM groups, revealing a possible pro-inflammatory status. In conclusion, omega oils induced conflicting alterations in middle-aged mice, contributing to enhanced behavior and anxiolytic and expanded motivational state, but also to increased stress response and pro-inflammatory alterations.

Fatty Acids: A Safe Tool for Improving Neurodevelopmental Alterations in Down Syndrome?

The triplication of chromosome 21 causes Down syndrome (DS), a genetic disorder that is characterized by intellectual disability (ID). The causes of ID start in utero, leading to impairments in neurogenesis, and continue into infancy, leading to impairments in dendritogenesis, spinogenesis, and connectivity. These defects are associated with alterations in mitochondrial and metabolic functions and precocious aging, leading to the early development of Alzheimer’s disease. Intense efforts are currently underway, taking advantage of DS mouse models to discover pharmacotherapies for the neurodevelopmental and cognitive deficits of DS. Many treatments that proved effective in mouse models may raise safety concerns over human use, especially at early life stages. Accumulating evidence shows that fatty acids, which are nutrients present in normal diets, exert numerous positive effects on the brain. Here, we review (i) the knowledge obtained from animal models regarding the effects of fatty acids on the brain, by focusing on alterations that are particularly prominent in DS, and (ii) the progress recently made in a DS mouse model, suggesting that fatty acids may indeed represent a useful treatment for DS. This scenario should prompt the scientific community to further explore the potential benefit of fatty acids for people with DS.

Oxidative Stress Mediates the Association Between Dietary Fat Intake and Cognition in US Older Adults

OBJECTIVE

Dietary fat intake was considered as a modifiable factor influencing cognitive performance. The objective was to 1) examine the associations between different types of dietary fat intakes and cognitive outcomes among elder adults (≥60 years old); 2) assess whether peripheral oxidative stress and antioxidant biomarkers are potential mediators of dietary fat intake and cognitive impairment relationship.

METHODS

Using data from National Health and Nutrition Examination Survey 2011-2014, total fat, saturated fatty acid (SFAT), monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), cholesterol, ω-3 and ω-6 fatty acids were used to evaluate dietary fat intakes. Cognitive outcomes were assessed by word learning and recall modules from the consortium to establish a registry for Alzheimer's Disease (CERAD), animal fluency test, and digit symbol substitution test (DSST). Antioxidant biomarkers were assessed by gamma glutamyl transpeptidase (GGT), bilirubin, uric acid, and vitamin D levels. Linear regression models and causal mediation analysis were applied to quantify the associations.

RESULTS

A total of 2,253 elder adults were included in the data analyses. Dietary intake of PUFA and ω-6 fatty acid were positively associated with DSST [β (95% CI): 0.06 (0.01,0.10), t statistic = 2.39, df= 2238, p = 0.02; β (95% CI): 0.06 (0.01,0.11), t statistic = 2.54, df= 2238, p = 0.01, respectively]. GGT was negatively associated with DSST [β (95% CI): -0.04 (-0.07, -0.01), t statistic = -2.73, df= 2239, p = 0.01], whereas uric acid was positively associated with CERAD total score [β (95% CI): 0.04 (0.00,0.08), t statistic = 2.03, df= 2233, p = 0.04]. The association between dietary intake of PUFA/ω -3/ω -6 and DSST performance was partially mediated by GGT level.

CONCLUSION

Our findings support that PUFAs in dietary sources were associated with lower risks for cognitive impairment partially via lowering oxidative stress. Dietary PUFA supplementation may potentially reduce risk of cognitive impairment via antioxidative mechanism.

Use of polyunsaturated fatty acids in prevention and treatment of gastrointestinal diseases, obesity and cancer

Fatty acids are important structural and functional elements of human body. We can distinguish several types: among others polyunsaturated fatty acids, which include omega-3 fatty acids (ω-3PUFA) and omega-6 fatty acids(ω-6PUFA). The first group has pleiotropic health-promoting effects, while the second group, ω-6PUFA, negatively affects the homeostasis of the human body and contributes to the development of numerous diseases. Both the amount and the relative ratio of these acids in the diet is an important factor affecting health and quality of life.

Laboratory and clinical studies indicate that ω-3PUFA have a positive effect on the therapy of illnesses such as obesity and inflammatory bowel disease (IBD). ω-3 PUFA supplementation also appears to have a helpful effect in the adjuvant treatment of colorectal cancer and recovery.

The Impact of Medium Chain and Polyunsaturated ω-3-Fatty Acids on Amyloid-β Deposition, Oxidative Stress and Metabolic Dysfunction Associated with Alzheimer's Disease

Alzheimer’s disease (AD), the most common cause of dementia in the elderly population, is closely linked to a dysregulated cerebral lipid homeostasis and particular changes in brain fatty acid (FA) composition. The abnormal extracellular accumulation and deposition of the peptide amyloid-β (Aβ) is considered as an early toxic event in AD pathogenesis, which initiates a series of events leading to neuronal dysfunction and death. These include the induction of neuroinflammation and oxidative stress, the disruption of calcium homeostasis and membrane integrity, an impairment of cerebral energy metabolism, as well as synaptic and mitochondrial dysfunction. Dietary medium chain fatty acids (MCFAs) and polyunsaturated ω-3-fatty acids (ω-3-PUFAs) seem to be valuable for disease modification. Both classes of FAs have neuronal health-promoting and cognition-enhancing properties and might be of benefit for patients suffering from mild cognitive impairment (MCI) and AD. This review summarizes the current knowledge about the molecular mechanisms by which MCFAs and ω-3-PUFAs reduce the cerebral Aβ deposition, improve brain energy metabolism, and lessen oxidative stress levels.

Binge eating among young adults: association with sociodemographic factors, nutritional intake, dietary n-6:n-3 ratio and impulsivity

Binge eating behaviour (BE) is the major symptom of binge eating disorder (BED). This study aimed to compare the nutritional intake in the presence or absence of BE, with a particular focus on dietary n-6:n-3 ratio, to assess the association between BE and impulsivity and the mediating effect of BMI on this association. A total of 450 university students (age 18-28 years) participated. The self-administered questionnaires were a semi-quantitative FFQ and the UPPS-P Impulsive Behavior Scale and the binge eating scale. The average BE score was 11·6 (se 7·388), and 20 % of the total participants scored above the cut-off of 17, thus presenting BE with 95 % CI of 16·3, 23·7 %. Our study revealed that greater BMI, higher total energy intake, greater negative urgency and positive urgency scores were significantly associated with BE. Participants with high value of dietary n-6:n-3 ratio were 1·335 more at risk to present a BE compared with those with a lower value of this ratio (P = 0·017). The relationship between BE score and UPPS domains score was not mediated by the BMI. This is the first study reporting a link between high dietary n-6:n-3 ratio and BE as well as the fact that BE was linked to both, negative and positive urgencies, and that the association between BE and impulsivity was not mediated by BMI. These findings can help to deal more efficiently with people suffering from BE, a symptom that can precede the development of BED.

Use of Active Salmon-Lecithin Nanoliposomes to Increase Polyunsaturated Fatty Acid Bioavailability in Cortical Neurons and Mice

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) play an important role in the development, maintenance, and function of the brain. Dietary supplementation of n-3 PUFAs in neurological diseases has been a subject of particular interest in preventing cognitive deficits, and particularly in age-related neurodegeneration. Developing strategies for the efficient delivery of these lipids to the brain has presented a challenge in recent years. We recently reported the preparation of n-3 PUFA-rich nanoliposomes (NLs) from salmon lecithin, and demonstrated their neurotrophic effects in rat embryo cortical neurons. The objective of this study was to assess the ability of these NLs to deliver PUFAs in cellulo and in vivo (in mice). NLs were prepared using salmon lecithin rich in n-3 PUFAs (29.13%), and characterized with an average size of 107.90 ± 0.35 nm, a polydispersity index of 0.25 ± 0.01, and a negative particle-surface electrical charge (-50.4 ± 0.2 mV). Incubation of rat embryo cortical neurons with NLs led to a significant increase in docosahexaenoic acid (DHA) (51.5%, p < 0.01), as well as palmitic acid, and a small decrease in oleic acid after 72 h (12.2%, p < 0.05). Twenty mice on a standard diet received oral administration of NLs (12 mg/mouse/day; 5 days per week) for 8 weeks. Fatty acid profiles obtained via gas chromatography revealed significant increases in cortical levels of saturated, monounsaturated, and n-3 (docosahexaenoic acid,) and n-6 (docosapentaenoic acid and arachidonic acid) PUFAs. This was not the case for the hippocampus or in the liver. There were no effects on plasma lipid levels, and daily monitoring confirmed NL biocompatibility. These results demonstrate that NLs can be used for delivery of PUFAs to the brain. This study opens new research possibilities in the development of preventive as well as therapeutic strategies for age-related neurodegeneration.

Improving Cognition with Nutraceuticals Targeting TGF-β1 Signaling

Rescue of cognitive function represents an unmet need in the treatment of neurodegenerative disorders such as Alzheimer's disease (AD). Nutraceuticals deliver a concentrated form of a presumed bioactive(s) agent(s) that can improve cognitive function alone or in combination with current approved drugs for the treatment of cognitive disorders. Nutraceuticals include different natural compounds such as flavonoids and their subclasses (flavan-3-ols, catechins, anthocyanins, and flavonols), omega-3, and carnosine that can improve synaptic plasticity and rescue cognitive deficits through multiple molecular mechanisms. A deficit of transforming growth factor-β1 (TGF-β1) pathway is an early event in the pathophysiology of cognitive impairment in different neuropsychiatric disorders, from depression to AD. In the present review, we provide evidence that different nutraceuticals, such as Hypericum perforatum (hypericin and hyperforin), flavonoids such as hesperidin, omega-3, and carnosine, can target TGF-β1 signaling and increase TGF-β1 production in the central nervous system as well as cognitive function. The bioavailability of these nutraceuticals, in particular carnosine, can be significantly improved with novel formulations (nanoparticulate systems, nanoliposomes) that increase the efficacy and stability of this peptide. Overall, these studies suggest that the synergism between nutraceuticals targeting the TGF-β1 pathway and current approved drugs might represent a novel pharmacological approach for reverting cognitive deficits in AD patients.

Free Fatty Acids Are Associated with the Cognitive Functions in Stroke Survivors

Ischemic stroke is a leading cause of motor impairment and psychosocial disability. Although free fatty acids (FFA) have been proven to affect the risk of stroke and potentially dementia, the evidence of their impact on cognitive functions in stroke patients is lacking. We aimed to establish such potential relationships. Seventy-two ischemic stroke patients were prospectively analysed. Their cognitive functions were assessed seven days post-stroke and six months later as follow-up (n = 41). Seven days post-stroke analysis of serum FFAs levels showed direct correlations between Cognitive Verbal Learning Test (CVLT) and the following FFAs: C20:4n6 arachidonic acid and C20:5n3 eicosapentaenoic acid, while negative correlations were observed for C18:3n3 linolenic acid (ALA), C18:4 n3 stearidonic acid and C23:0 tricosanoic acid. Follow-up examination with CVLT revealed positive correlations with C15:0 pentadecanoid acid, C18:3n6 gamma linoleic acid, SDA, C23:0 tricosanoic acid and negative correlations with C14:0 myristic acid and C14:1 myristolenic acids. Several tests (Trail Making Test, Stroop Dots Trail, Digit Span Test and Verbal Fluency Test) were directly correlated mainly with C14:0 myristic acid and C14:1 myristolenic acid, while corresponding negatively with C18:1 vaccinic acid, C20:3n3 cis-11-eicosatrienoic acid, C22:1/C20:1 cis11- eicosanic acid and C20:2 cis-11-eicodienoic acid. No correlations between Montreal Cognitive Assessment (MOCA) test performed on seventh day, and FFAs levels were found. Saturated fatty acids play a negative role in long-term cognitive outcomes in stroke patients. The metabolic cascade of polyunsaturated fatty acids (n3 PUFA) and the synthesis of (AA) can be involved in pathogenesis of stroke-related cognitive impairment.

Amyloid Oligomers: A Joint Experimental/Computational Perspective on Alzheimer's Disease, Parkinson's Disease, Type II Diabetes, and Amyotrophic Lateral Sclerosis

Protein misfolding and aggregation is observed in many amyloidogenic diseases affecting either the central nervous system or a variety of peripheral tissues. Structural and dynamic characterization of all species along the pathways from monomers to fibrils is challenging by experimental and computational means because they involve intrinsically disordered proteins in most diseases. Yet understanding how amyloid species become toxic is the challenge in developing a treatment for these diseases. Here we review what computer, in vitro, in vivo, and pharmacological experiments tell us about the accumulation and deposition of the oligomers of the (Aβ, tau), α-synuclein, IAPP, and superoxide dismutase 1 proteins, which have been the mainstream concept underlying Alzheimer's disease (AD), Parkinson's disease (PD), type II diabetes (T2D), and amyotrophic lateral sclerosis (ALS) research, respectively, for many years.

Walnut-Associated Fatty Acids Inhibit LPS-Induced Activation of BV-2 Microglia

Walnuts have high levels of the omega-3 fatty acid alpha-linolenic acid (C18:3n-3, ALA) and the omega-6 fatty acid linoleic acid (C18:2n-6, LA). Previous research has demonstrated that pre-treatment of BV-2 microglia with walnut extract inhibited lipopolysaccharide (LPS)-induced activation of microglia. As an extension of that study, the effects of walnut-associated fatty acids on BV-2 microglia were assessed. BV-2 murine microglia cells were treated with LA, ALA, or a combination of LA+ALA prior to or after exposure to LPS. Nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) were measured in cell-conditioned media. Cyclooxeganse-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression were assessed in BV-2 microglia. Both LA and ALA protected against LPS-induced increases in NO, iNOS, COX-2, and TNF-alpha when used before LPS exposure. When BV-2 microglia were treated with fatty acids after LPS, only COX-2 and TNF-alpha were significantly attenuated by the fatty acids. There was no synergism of LA+ALA, as the LA+ALA combination was no more effective than LA or ALA alone. Fatty acids, like those found in walnuts, may protect against production of cytotoxic intermediates and cell-signaling molecules from microglia and may prove beneficial for preventing age- or disease-related neurodegeneration.

Alzheimer's Disease and Specialized Pro-Resolving Lipid Mediators: Do MaR1, RvD1, and NPD1 Show Promise for Prevention and Treatment?

Alzheimer's disease (AD) is a common neurodegenerative disease and a major contributor to progressive cognitive impairment in an aging society. As the pathophysiology of AD involves chronic neuroinflammation, the resolution of inflammation and the group of lipid mediators that actively regulate it-i.e., specialized pro-resolving lipid mediators (SPMs)-attracted attention in recent years as therapeutic targets. This review focuses on the following three specific SPMs and summarizes their relationships to AD, as they were shown to effectively address and reduce the risk of AD-related neuroinflammation: maresin 1 (MaR1), resolvin D1 (RvD1), and neuroprotectin D1 (NPD1). These three SPMs are metabolites of docosahexaenoic acid (DHA), which is contained in fish oils and is thus easily available to the public. They are expected to become incorporated into promising avenues for preventing and treating AD in the future.

Involvement of Lipids in Alzheimer's Disease Pathology and Potential Therapies

Lipids constitute the bulk of the dry mass of the brain and have been associated with healthy function as well as the most common pathological conditions of the brain. Demographic factors, genetics, and lifestyles are the major factors that influence lipid metabolism and are also the key components of lipid disruption in Alzheimer's disease (AD). Additionally, the most common genetic risk factor of AD, APOE ϵ4 genotype, is involved in lipid transport and metabolism. We propose that lipids are at the center of Alzheimer's disease pathology based on their involvement in the blood-brain barrier function, amyloid precursor protein (APP) processing, myelination, membrane remodeling, receptor signaling, inflammation, oxidation, and energy balance. Under healthy conditions, lipid homeostasis bestows a balanced cellular environment that enables the proper functioning of brain cells. However, under pathological conditions, dyshomeostasis of brain lipid composition can result in disturbed BBB, abnormal processing of APP, dysfunction in endocytosis/exocytosis/autophagocytosis, altered myelination, disturbed signaling, unbalanced energy metabolism, and enhanced inflammation. These lipid disturbances may contribute to abnormalities in brain function that are the hallmark of AD. The wide variance of lipid disturbances associated with brain function suggest that AD pathology may present as a complex interaction between several metabolic pathways that are augmented by risk factors such as age, genetics, and lifestyles. Herewith, we examine factors that influence brain lipid composition, review the association of lipids with all known facets of AD pathology, and offer pointers for potential therapies that target lipid pathways.

A More Comprehensive Approach to the Neuroprotective Potential of Long-Chain Polyunsaturated Fatty Acids in Preterm Infants Is Needed-Should We Consider Maternal Diet and the n-6:n-3 Fatty Acid Ratio?

There is growing evidence that long-chain polyunsaturated fatty acids (LCPUFAs) are of importance for normal brain development. Adequate supply of LCPUFAs may be particularly important for preterm infants, because the third trimester is an important period of brain growth and accumulation of arachidonic acid (n-6 LCPUFA) and docosahexaenoic acid (n-3 LCPUFA). Fatty acids from the n-6 and n-3 series, particularly, have important functions in the brain as well as in the immune system, and their absolute and relative intakes may alter both the risk of impaired neurodevelopment and response to injury. This narrative review focuses on the potential importance of the n-6:n-3 fatty acid ratio in preterm brain development. Randomized trials of post-natal LCPUFA supplementation in preterm infants are presented. Pre-clinical evidence, results from observational studies in preterm infants as well as studies in term infants and evidence related to maternal diet during pregnancy, focusing on the n-6:n-3 fatty acid ratio, are also summarized. Two randomized trials in preterm infants have compared different ratios of arachidonic acid and docosahexaenoic acid intakes. Most of the other studies in preterm infants have compared formula supplemented with arachidonic acid and docosahexaenoic acid to un-supplemented formula. No trial has had a comprehensive approach to differences in total intake of both n-6 and n-3 fatty acids during a longer period of neurodevelopment. The results from preclinical and clinical studies indicate that intake of LCPUFAs during pregnancy and post-natal development is of importance for neurodevelopment and neuroprotection in preterm infants, but the interplay between fatty acids and their metabolites is complex. The best clinical approach to LCPUFA supplementation and n-6 to n-3 fatty acid ratio is still far from evident, and requires in-depth future studies that investigate specific fatty acid supplementation in the context of other fatty acids in the diet.

Serum Carotenoids, Tocopherols, Total n-3 Polyunsaturated Fatty Acids, and n-6/n-3 Polyunsaturated Fatty Acid Ratio Reflect Brain Concentrations in a Cohort of Centenarians

Investigating the role of nutrition on cognitive health is challenging. Human brain tissue is inaccessible in living humans and is often limited in deceased individuals. Therefore, biomarkers of brain nutrient levels are of interest. The objective of this study was to characterize the relationships between levels of fat-soluble nutrients in serum and matched brain tissues from the frontal and temporal cortices of participants in the Georgia Centenarian Study (n = 47). After adjusting for sex, race, cognitive status (Global Deterioration Scale), body mass index, and presence of hypertension and/or diabetes, there was a significant relationship (p < 0.05) between serum and brain levels of carotenoids (lutein, zeaxanthin, cryptoxanthin, β-carotene), α-, γ-tocopherols, total n-3 polyunsaturated fatty acids (PUFAs), and n-6/n-3 PUFA ratio. The relationship between serum and brain total n-6 PUFAs was inconsistent among the two brain regions. No significant relationship was identified between serum and brain retinol, total saturated fatty acid, total monounsaturated fatty acid, and trans-fatty acid levels. These findings suggest that serum carotenoids, tocopherols, total n-3 PUFAs, and n-6/n-3 PUFA ratio reflect levels in brain and can be used as surrogate biomarkers in older population.

Diet Associated with Inflammation and Alzheimer's Disease

Neurocognitive disorders, such as Alzheimer's disease (AD), affect millions of people worldwide and are characterized by cognitive decline. Human and animal studies have shown that chronic immune response and inflammation are important factors in the pathogenesis of AD. Chronic inflammation can accelerate the aggregation of amyloid-β peptides and later hyperphosphorylation of tau proteins. The exact etiology of AD is not clear, but genetics and environmental factors, such as age, family history, and lifestyle are linked to neurodegenerative diseases. Lifestyle habits, such as poor diet, are associated with inflammation and could accelerate or slow down the progression of neurodegenerative diseases. Here we provide a review of the potential conditions and factors that stimulate the inflammatory processes in AD. An understanding of inflammatory mechanisms influencing the development of AD may help to protect against dementia and AD.

Omega-3 PUFA metabolism and brain modifications during aging

In Canada, 5.5 million (16% of Canadians) adults are >65 years old and projections suggest this number will be approximately 20% of Canadians by 2024. A major concern regarding old age is a decline in health, especially if this entails a loss of self-sufficiency and independence caused by a decline in cognition. The brain contains 60% of fat and is one of the most concentrated organs in long chain omega-3 fatty acids such as docosahexaenoic acid (DHA). During aging, there are physiological modifications in the metabolism of lipids that could also have consequences on brain structure and levels of DHA. This review will hence discuss the physiological modifications in the metabolism of lipids during aging with a focus on long chain omega-3 and omega-6 fatty acids and also outline the structural and functional modifications of the brain during aging including brain lipid modifications and its relation to higher levels of DHA and cognition. Therefore, in this review, we outline the importance of collecting more data on the biology of aging since it might highly improve our understanding about what are «normal» modifications occurring during aging and what can become pathological.

The association of blood non-esterified fatty acid, saturated fatty acids, and polyunsaturated fatty acids levels with mild cognitive impairment in Chinese population aged 35-64 years: a cross-sectional study

OBJECTIVES

The aim of this study was to explore the correlation between blood profiles and cognitive functions or mild cognitive impairment (MCI) in the Chinese population aged 35-64 years old.

METHODS

A cross-sectional study was performed, which recruited 675 Chinese adults aged 35-64 years old from Beijing, China. Their cognitive performance was assessed with Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA), the serum lipids levels were measured by hexokinase method and colorimetric assay, and the plasma fatty acids profiles were analyzed by fast gas chromatography.

RESULTS

Among the 675 participants, 84 (12.4%) had MCI. Age, years of education, saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) were associated with MMSE scores (all P < 0.05). Age, years of education, smoking, drinking, non-esterified fatty acids (NEFAs), SFAs, MUFAs, n-3 polyunsaturated fatty acids (n-3 PUFAs) and n-6/n-3 PUFAs were associated with MoCA scores (all P < 0.05). Increased age (P = 0.002) and smoking (P = 0.028) were positively associated with the prevalence of MCI, while educational level (P = 0.005) and alcohol drinking (P = 0.003) both were negatively correlated to the prevalence of MCI. Elevated serum NEFAs (P = 0.032), high plasma SFAs (P = 0.023), and excessive polyunsaturated fatty acids (PUFAs) levels (P = 0.033) were significantly associated with increased frequency of MCI.

CONCLUSION

In the Chinese population aged 35-64 years, advanced age and cigarette smoking were risk factors of MCI, whereas higher educational level and alcohol drinking were protective factors for MCI. Excessive serum or plasma levels of NEFAs, SFAs and PUFAs were associated with an increased risk of MCI.

Docosahexaenoic acid (22:6n-3) Ameliorated the Onset and Severity of Experimental Autoimmune Encephalomyelitis in Mice

Multiple sclerosis (MS) is a neurologic autoimmune disease, which is the leading cause of nontraumatic neurologic disability in young adults in United States and Europe. n-3 polyunsaturated fatty acids (PUFA) are reported to mitigate severity of this disease. Recent studies suggest that phospholipid (PL) form of dietary n-3 PUFA may lead to their higher tissue accretion than triacylglycerol (TAG) form. We compared efficacy of PL-docosahexaenoic acid (22:6n-3) (DHA) and TAG-DHA on onset and severity of experimental autoimmune encephalomyelitis (EAE) in a mouse model of MS. Female mice were fed low alpha-linolenic acid (18:3n-3) (ALA) diet (control) for 2 weeks and then fed either control, 0.3%, or 1.0% DHA (PL or TAG) for 4 weeks pre-EAE induction and 4 weeks post-EAE induction. The brain and spinal cord n-6:n-3 ratio was significantly lower in all mice fed DHA compared to control. EAE onset was delayed in mice fed both DHA forms and concentrations, except for 1% TAG-DHA. The inverse association between the EAE score and the brain DHA concentration was nonsignificant at the end of the study (p = 0.08). Daily EAE scores of mice fed different DHA diets did not differ from control, however, the score of all DHA groups combined during days 9-16 was lower (p = 0.028) compared to the control. During days 17-22, the EAE score trended lower in 0.3% TAG-DHA and during days 23-28, the EAE score trended lower in both PL-DHA groups than those in all other groups. These findings suggest that TAG-DHA may be more effective than PL-DHA in the early phases of EAE, and in the final outcome, PL-DHA may be more effective than TAG-DHA.

Prevalence and Causes of Cognitive Impairment and Dementia in a Population-Based Cohort From Northern Portugal

BACKGROUND

Vascular disease may play an important role in the epidemiology of dementia in countries with high stroke incidence, such as Portugal.

OBJECTIVE

To assess the prevalence and etiology of cognitive impairment in a population-based cohort from Portugal.

METHODS

Individuals ≥55 years (n = 730) from the EPIPorto cohort were assessed using the Mini-Mental State Examination and the Montreal Cognitive Assessment. Those scoring below the age-/education-adjusted cutoff points were further evaluated to identify dementia or mild cognitive impairment (MCI) and to define its most common causes.

RESULTS

Thirty-six cases of MCI/dementia were identified, corresponding to adjusted prevalences of 4.1% for MCI and 1.3% for dementia. The most common cause of MCI/dementia was vascular (52.8%), followed by Alzheimer's disease (36.1%).

CONCLUSION

These findings highlight the importance of vascular cognitive impairment in the epidemiology of dementia in Portugal and carry an important public health message regarding its prevention and management, possibly extending to other countries with a high-stroke burden.

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

Background

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

Objectives

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

Methods

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

Results

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

Conclusion

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

Apolipoprotein E genotype moderates the association between dietary polyunsaturated fat and brain function: an exploration of cerebral glutamate and cognitive performance

Objective: To investigate the effect of Apolipoprotein E (APOE) genotype on the association between dietary polyunsaturated fat (PUFA), cognitive function, and cerebral glutamate. Methods: A participant sample of 122 middle-aged adults were grouped according to APOE genotype (ϵ4 carrier or ϵ4 non-carrier) and asked to record dietary intake for three consecutive days. All participants also underwent neuropsychological testing and a proton magnetic resonance spectroscopy (¹H MRS) scan to assess glutamate in the posterior cingulate cortex. Results: Multiple regression analyses revealed a significant interaction between APOE genotype and PUFA intake on memory performance, F(1,113) = 6.749, p = .016. Greater PUFA intake was associated with better memory performance in healthy middle-aged adults who were APOE ϵ4 non-carriers, but not for ϵ4 carriers. Furthermore, there was a significant interaction between APOE genotype and PUFA intake on cerebral glutamate, in that dietary PUFA was associated with greater cerebral glutamate in APOE ϵ4 carriers, but not for ϵ4 non-carriers, F(1,114) = 5.173, p = .025. Conclusions: The findings suggest that PUFA action on the brain differs according to APOE polymorphism and points towards cerebral glutamate as a potential marker of genetic risk for Alzheimer's disease (AD). Early treatment consisting of PUFA supplementation that is tailored to APOE genotype may be an important intervention for the prevention of cognitive decline.

Patients and agents - or why we need a different narrative: a philosophical analysis

BACKGROUND

The success of medicine in the treatment of patients brings with it new challenges. More people live on to suffer from functional, chronic or multifactorial diseases, and this has led to calls for more complex analyses of the causal determinants of health and illness.

METHODS

Philosophical analysis of background assumptions of the current paradigmatic model.

RESULTS

While these factors do not require a radical paradigm shift, they do give us cause to develop a new narrative, to add to existing narratives that frame our thinking about medical care. In this paper we argue that the increased focus on lifestyle and shared decision making requires a new narrative of agency, to supplement the narrative of "the patient". This narrative is conceptually linked to the developing philosophy of person-centred care.

CONCLUSIONS

If patients are seen also as "agents" this will result in a substantial shift in practical decisions: The development and adoption of this narrative will help practitioners work with patients to their mutual benefit, harnessing the patients' motivation, shifting the focus from treatment to prevention and preventing unnecessary and harmful treatments that can come out of our preoccupation with the patient narrative. It will also help to shift research efforts, conceptual and empirical, from "treating" and "battling" diseases and their purported "mechanisms" to understanding complex contributing factors and their interplay.

Optimizing long chain-polyunsaturated fatty acid synthesis in salmonids by balancing dietary inputs

The increasing use of terrestrial plant lipids to replace of fish oil in commercial aquafeeds requires understanding synthesis and storage of long chain-polyunsaturated fatty acids (LC-PUFA) in farmed fish. Manipulation of dietary fatty acids may maximize tissue storage of LC-PUFA, through increased production and selective utilization. A data synthesis study was conducted to estimate optimal levels of fatty acids that may maximize the production and storage of LC-PUFA in the edible portion of salmonids. Data were compiled from four studies with Atlantic salmon, rainbow trout, and steelhead trout (total n = 180) which were fed diets containing different terrestrial-based oils to replace fish oil. LC-PUFA (%) were linearly correlated between diet and muscle tissue (p < 0.001; r² > 44%), indicating proportional storage after consumption. The slope, or retention rate, was highest for docosahexaenoic acid (DHA) at 1.23, indicating that an additional 23% of DHA was stored in the muscle. Dietary saturated fatty acids were positively related to DHA stored in the muscle (p < 0.001; r² = 22%), which may involve membrane structural requirements, as well as selective catabolism. DHA was found to be optimally stored with a dietary n-3: n-6 ratio of 1.03: 1. These new results provide a baseline of optimal dietary ratios that can be tested experimentally to determine the efficacy of balancing dietary fatty acids for maximum LC-PUFA storage.

Low dietary n-6/n-3 polyunsaturated fatty acid ratio prevents induced oral carcinoma in a hamster pouch model

Dietary fatty acid patterns have been linked to the prevalence of certain cancers, however in oral carcinoma is limited. Thus, we investigated the chemopreventive effects of various dietary n-6 and n-3 fatty acids in a 9,10-dimethyl-1,2-benz[a]-anthracene (DMBA)- and betel quid extract (BQE) -induced hamster oral cancer model. Thirty 6-week-old adult male hamsters were housed and divided into normal, low, and high dietary n-6 and n-3 fatty acid groups under DMBA + BQE treatment for 16 weeks. The right buccal pouch of all hamsters were evaluated by tumor number, volume, burden and selected inflammatory parameters. The results indicate that the low dietary n-6/n-3 fatty acid group exhibited a significantly lower tumor number, volume, and burden than those of the other groups. Furthermore, this group had significantly lower nuclear factor-κB, proliferating cell nuclear antigen, and cyclin D1 expression in the right buccal pouch tissue. In conclusion, the lower dietary n-6/n-3 fatty acid ratio exerted chemopreventive effects in the DMBA- and BQE-induced hamster oral cancer model.

Omega-6:3 Ratio More Than Absolute Lipid Level in Diet Affects Associative Learning in Honey Bees

Floral pollen is a major source of honey bee nutrition that provides them with micro- and macro-nutrients, including proteins, fatty acids, vitamins, and minerals. Different pollens vary in composition, including in the essential fatty acids, alpha-linolenic acid (omega-3) and linoleic acid (omega-6). Monocultures, prevalent in modern agriculture, may expose honey bee colonies to unbalanced omega-6:3 diets. The importance of omega-3 in the diet for adequate learning and cognitive function, with a focus on suitable omega-6:3 ratio, is well documented in mammals. We have recently shown, for the first time in invertebrates, the importance of omega-3 in diets for associative learning ability in honey bees. In the current work, we examine the effect of the absolute amount of omega-3 in diet compared to the omega-6:3 ratio on honey bee associative learning. We fed newly emerged bees for 1 week on different artificial diets, which had lipid concentration of 1, 2, 4, or 8%, with omega-6:3 ratios of 0.3, 1, or 5, respectively. We then tested the bees in a proboscis-extension response olfactory conditioning assay. We found that both omega-6:3 ratio and total lipid concentration affected learning. The most detrimental diet for learning was that with a high omega-6:3 ratio of 5, regardless of the absolute amount of omega-3 in the diet. Bees fed an omega-6:3 ratio of 1, with 4% total lipid concentration achieved the best performance. Our results with honey bees are consistent with those found in mammals. Best cognitive performance is achieved by a diet that is sufficiently rich in essential fatty acids, but as long as the omega-6:3 ratio is not high.

Are pupils' 'Programme for International Student Assessment (PISA)' scores associated with a nation's fish consumption?

AIMS

Omega-3 fatty acids are essential for neurodevelopment. Fish is a major source of these essential nutrients. We asked whether a nation's fish consumption is associated with its pupils' PISA scores as measures of school achievement, independent of economic status and breastfeeding. Method (Design and Setting): This was a regression analytic study based on published data.

RESULTS

Data on fish consumption and PISA scores were available for 64 countries. A significant regression model explained 72% of the variance in PISA scores. Breastfeeding does not enter the model. After controlling for technical and/or economic development, a nation's fish consumption remains a significant predictor, explaining an additional 4% of the variance.

DISCUSSION

This effect is likely due to the fact that fish, as the major source of omega-3 polyunsaturated fatty acids for a population, is important for the omega-3 supply to mothers and the early neurodevelopment of their children.

CONCLUSIONS

Fish consumption, as a proxy for a population's omega-3 supply, is an independent predictor of pupils' school achievement, in addition to a nation's economic development.

Emotion-Based Cognition in Mice Is Differentially Influenced by Dose and Chemical Form of Dietary Docosahexaenoic Acid

Docosahexaenoic acid (DHA) is a major constituent, and primary omega-3 fatty acid, in the brain. Evidence suggests that DHA consumption may promote cognitive functioning and prevent cognitive decline, and these effects may be particularly relevant in the context of fear or stress. However, the potency and efficacy of dietary DHA may depend on the form of DHA (e.g., phospholipid; PL vs. triglyceride; TG). In this study, we compared in mice the effects of consuming PL and TG forms of DHA on associative, avoidance (fear) based learning and memory. Diets consisted of either no DHA or 1%, 2%, and 4% PL- or TG-DHA. After 4 weeks on the test diets (n = 12/group), we used the 3-day passive avoidance (PA) and elevated plus maze (EPM) to examine fear and fear-associated learning and memory. We found a significant (p < 0.05) diet by time interaction in the PA and EPM. Compared to the control and the 1% TG-DHA group, mice consuming the diet supplemented with 1% PL-DHA displayed a significantly greater latency by test day 2 in the 3-day PA. No differences in latency between any of the groups were observed during trials 1 and 3. Mice consuming the 2% PL-DHA diet spent significantly more time frequenting the open arms during the first minute, but not the last 4 min, of the test. Compared to all other groups, mice fed the 4% TG-DHA diet had increased spleen, liver, and visceral fat weight. Consumption of the lower dose PL-DHA may confer enhanced efficacy, particularly on fear-based learning behavior.

Carriers of an apolipoprotein E epsilon 4 allele are more vulnerable to a dietary deficiency in omega-3 fatty acids and cognitive decline

Carriers of an epsilon 4 allele (E4) of apolipoprotein E (APOE) develop Alzheimer's disease (AD) earlier than carriers of other APOE alleles. The metabolism of plasma docosahexaenoic acid (DHA, 22:6n-3), an omega-3 fatty acid (n-3 FA), taken up by the brain and concentrated in neurons, is disrupted in E4 carriers, resulting in lower levels of brain DHA. Behavioural and cognitive impairments have been observed in animals with lower brain DHA levels, with emphasis on loss of spatial memory and increased anxiety. E4 mice provided a diet deficient in n-3 FA had a greater depletion of n-3 FA levels in organs and tissues than mice carrying other APOE alleles. However, providing n-3 FA can restore levels of brain DHA in E4 animals and in other models of n-3 FA deficiency. In E4 carriers, supplementation with DHA as early as possible might help to prevent the onset of AD and could halt the progression of, and reverse some of the neurological and behavioural consequences of their higher vulnerability to n-3 FA deficiency.

Predictors of Memory in Healthy Aging: Polyunsaturated Fatty Acid Balance and Fornix White Matter Integrity

Recent evidence demonstrates that age and disease-related decline in cognition depends not only upon degeneration in brain structure and function, but also on dietary intake and nutritional status. Memory, a potential preclinical marker of Alzheimer's disease, is supported by white matter integrity in the brain and dietary patterns high in omega-3 and omega-6 polyunsaturated fatty acids. However, the extent to which memory is supported by specific omega-3 and omega-6 polyunsaturated fatty acids, and the degree to which this relationship is reliant upon microstructure of particular white matter regions is not known. This study therefore examined the cross-sectional relationship between empirically-derived patterns of omega-3 and omega-6 polyunsaturated fatty acids (represented by nutrient biomarker patterns), memory, and regional white matter microstructure in healthy, older adults. We measured thirteen plasma phospholipid omega-3 and omega-6 polyunsaturated fatty acids, memory, and regional white matter microstructure in 94 cognitively intact older adults (65 to 75 years old). A three-step mediation analysis was implemented using multivariate linear regressions, adjusted for age, gender, education, income, depression status, and body mass index. The mediation analysis revealed that a mixture of plasma phospholipid omega-3 and omega-6 polyunsaturated fatty acids is linked to memory and that white matter microstructure of the fornix fully mediates the relationship between this pattern of plasma phospholipid polyunsaturated fatty acids and memory. These results suggest that memory may be optimally supported by a balance of plasma phospholipid omega-3 and omega-6 polyunsaturated fatty acids through the preservation of fornix white matter microstructure in cognitively intact older adults. This report provides novel evidence for the benefits of plasma phospholipid omega-3 and omega-6 polyunsaturated fatty acid balance on memory and underlying white matter microstructure.

Docosahexaenoic acid (DHA) and arachidonic acid (ARA) balance in developmental outcomes

The DHA Intake and Measurement of Neural Development (DIAMOND) trial represents one of only a few studies of the long-term dose-response effects of LCPUFA-supplemented formula feeding during infancy. The trial contrasted the effects of four formulations: 0.00% docosahexaenoic acid (DHA)/0.00% arachidonic acid (ARA), 0.32% DHA/0.64% ARA, 0.64% DHA/0.64% ARA, and 0.96% DHA/0.64% ARA against a control condition (0.00% DHA/0.00% ARA). The results of this trial have been published elsewhere, and show improved cognitive outcomes for infants fed supplemented formulas, but a common finding among many of the outcomes show a reduction of benefit for the highest DHA dose (i.e., 0.96%DHA/0.64% ARA, that is, a DHA: ARA ratio 1.5:1.0). The current paper gathers and summarizes the evidence for the reduction of benefit at this dose, and in an attempt to account for this reduced benefit, presents for the first time data from infants' red blood cell (RBC) assays taken at 4 and 12 months of age. Those assays indicate that blood DHA levels generally rose with increased DHA supplementation, although those levels tended to plateau as the DHA-supplemented level exceeded 0.64%. Perhaps more importantly, ARA levels showed a strong inverted-U function in response to increased DHA supplementation; indeed, infants assigned to the formula with the highest dose of DHA (and highest DHA/ARA ratio) showed a reduction in blood ARA relative to more intermediate DHA doses. This finding raises the possibility that reduced ARA may be responsible for the reduction in benefit on cognitive outcomes seen at this dose. The findings implicate the DHA/ARA balance as an important variable in the contribution of LCPUFAs to cognitive and behavioral development in infancy.

Effects of Long-Chain Omega-3 Polyunsaturated Fatty Acids on Endothelial Vasodilator Function and Cognition-Are They Interrelated?

Long-chain omega-3 polyunsaturated fatty acids (LCn-3 PUFA) may improve brain functions by acting on endothelial cells in the cerebrovasculature to facilitate vasodilatation and perfusion. The aim of this review is to explore this hypothesis by analyzing the effect of LCn-3 PUFA supplementation on systemic vasodilator and cognitive function and finding evidence to link LCn-3 PUFA intake, vasodilator function and cognition. Forty randomized controlled trials examining the effect of LCn-3 PUFA supplementation in humans on either endothelial vasodilator function or cognition were identified and pooled effects measured with a weighted analysis. Compared to placebo, LCn-3 PUFA tended to increase flow-mediated dilatation and significantly improved cognitive function. Emerging evidence links vasodilator dysfunction to cognitive impairment, but evidence that LCn-3 PUFA can improve cognition through enhancements of vasodilator function is still lacking. Further research is needed to determine: (1) whether LCn-3 PUFA can enhance dilatation of cerebral vessels; (2) if improvements in cerebrovascular responsiveness by LCn-3 PUFA are accompanied by cognitive benefits; and (3) the target population groups.

Contributions of polyunsaturated fatty acids (PUFA) on cerebral neurobiology: an integrated omics approach with epigenomic focus

The epigenetic landscape is vulnerable to diets. Here, we investigated the influence of different polyunsaturated fatty acids (PUFA) dietary supplements on rodents' nervous system development and functions and potential consequences to neurodegenerative disorders. Our previous nutrigenomics study showed significant impact of high n-3 PUFA-enriched diet (ERD) on synaptogenesis and various neuromodulators. The present study introduced a second equicaloric diet with n-6 PUFA balanced by n-3 PUFA (BLD). The typical lab diet with high n-6 PUFA was the baseline. Transcriptomic and epigenetic investigations, namely microRNA (miRNA) and DNA methylation assays, were carried out on the hemibrains of the C57BL/6j mice fed on any of these three diets from their neonatal age to midlife. Integrating the multiomics data, we focused on the genes encoding both hypermethylated CpG islands and suppressed transcripts. In addition, miRNA:mRNA pairs were screened to identify those overexpressed miRNAs that reduced transcriptional expressions. The majority of miRNAs overexpressed by BLD are associated with Alzheimer's and schizophrenia. BLD implicated long-term potentiation, memory, cognition and learning, primarily via hypermethylation of those genes that enrich the calcium-releasing neurotransmitters. ERD caused hypermethylation of those genes that enrich cytoskeletal development networks and promote the formation of neuronal precursors. We drew the present observations in light of our limited knowledge regarding the epigenetic influences on biofunctions. A more comprehensive study is essential to understand the broad influences of dietary supplements and to suggest optimal dietary solutions for neurological disorders.

Enriched endogenous n-3 polyunsaturated fatty acids alleviate cognitive and behavioral deficits in a mice model of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that accompanied by memory deficits and neuropsychiatric dysfunction. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have seemly therapeutic potential in AD, but the benefit of n-3 PUFAs is still in debates. Here, we employed a transgenic mice carry fat-1 gene to encode n-3 desaturase from Caenorhabditis elegans, which increase endogenous n-3 PUFAs by converting n-6 PUFAs to n-3 PUFAs crossed with amyloid precursor protein (APP) Tg mice to evaluate the protective effects of endogenous n-3 PUFAs on cognitive and behavioral deficits of APP Tg mice. We fed APP, APP/fat-1 and fat-1 mice with n-6 PUFAs rich diet. Brain tissues were collected at 3, 9 and 12 months for fatty acid and gene expression analysis, histology and protein assays. Morris Water Maze Test, open field test and elevated plus maze test were performed to measure the behavior capability. From the results, the expression of fat-1 transgene increased cortical n-3: n-6 PUFAs ratio and n-3 PUFAs concentrations, and sensorimotor dysfunction and cognitive deficits in AD were significantly less severe in APP/fat-1 mice with endogenous n-3 PUFAs than in APP mice controls. The protection against disturbance of spontaneous motor activity and cognitive deficits in AD was strongly correlated with increased n-3: n-6 PUFAs ratio and endogenous n-3 PUFAs, reduced APP generation, inhibited amyloid β peptide aggregation, suppressed nuclear factor-kappa B and astroglia activation, and reduced death of neurons in the cortex of APP/fat-1 mice compared with APP mice controls. In conclusion, our study demonstrates that an available medication with the maintenance of enriched n-3 PUFAs in the brain could slow down cognitive decline and prevent neuropsychological disorder in AD.

Ratio of dietary ω-3 and ω-6 fatty acids-independent determinants of muscle mass-in hemodialysis patients with diabetes

OBJECTIVE

ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) are essential nutrients in the human diet and possibly affect muscle mass. We evaluated the association between the dietary ratios of ω-3 and ω-6 PUFAs and muscle mass, indicated as skeletal muscle mass (SMM) and appendicular skeletal muscle mass (ASM), in patients with diabetes undergoing hemodialysis (HD).

METHODS

In this cross-sectional study, data on 69 patients with diabetes who underwent standard HD therapy were analyzed. For estimating muscle mass, anthropometric and bioelectrical impedance analyses were conducted following dialysis. In addition, routine laboratory and 3-d dietary data were obtained. The adequate intake (AI) cut-off for ω-3 PUFAs was 1.6 g/d and 1.1 g/d for male and female patients, respectively.

RESULTS

The average age of the participants was 63.0 ± 10.4 y. The mean ratios of ω-3/ω-6 PUFA intake, ω-6/ω-3 PUFA intake, SMM, and ASM of the patients were 0.13 ± 0.07, 9.4 ± 6.4, 24.6 ± 5.4 kg, and 18.3 ± 4.6 kg, respectively. Patients who had AI of ω-3 PUFAs had significantly higher SMM and ASM than did their counterparts. Linear and stepwise multivariable adjustment analyses revealed that insulin resistance and the ω-6/ω-3 PUFA ratio were the independent deleterious determinants of ASM normalized to height in HD patients.

CONCLUSIONS

Patients with AI of ω-3 PUFAs had total-body SMM and ASM that were more appropriate. A higher dietary ratio of ω-6/ω-3 PUFAs was associated with reduced muscle mass in HD patients.