Structured Long-Chain Omega-3 Fatty Acids for Improvement of Cognitive Function during Aging

Nutrigenomics and neurological disorders: exploring diet-brain interactions for cognitive health

This review article investigates the intricate relationship between nutrigenomics and neurological disorders, highlighting how genetic variations affect an individual's response to nutrients. The study delves into the role of diet-related oxidative stress and the gut-brain axis in the progression and management of brain disorders such as Parkinson's disease, Alzheimer's disease, epilepsy, stroke, migraines, and depression. The review encompasses various clinical trials and introduces new trends and techniques, including omics and artificial intelligence, in identifying and managing neurological disorders. The main findings emphasize that personalized diet recommendations, tailored to an individual's genetic makeup, can significantly improve cognitive health and manage neurological conditions. The study concludes that further research in the field of nutrigenomics is essential to advancing personalized nutrition strategies for better neurological functioning, ultimately linking diet, genes, and brain health.

Docosahexaenoic Acid (DHA) Supplementation in a Triglyceride Form Prevents from Polyglutamine-Induced Dysfunctions in Caenorhabditis elegans

A common hallmark of neurodegenerative diseases is the accumulation of polypeptide aggregates in neurons. Despite the primary cause of these diseases being inherently genetic, their development can be delayed with proper preventive treatments. Long-chain polyunsaturated fatty acids (ω-3 LCPUFA) are promising bioactive nutrients that are beneficial for brain health. In this study, the impact of an oil rich in a structured form of docosahexaenoic acid (DHA) triglyceride (TG) was assessed in a Caenorhabditis elegans model expressing long poly-glutamine (polyQ) chains, which mimics the symptomatology of polyQ-related neurodegenerative diseases such as Huntington's disease (HD), among others. The lifespan, the motility, the number of polyQ aggregates, the oxidative stress resistance, and the cognitive performance associated with sensitive stimuli was measured in mutant nematodes with polyQ aggregates. Overall, DHA-TG at 0.5 µM improved the lifespan, the motility, the oxidative stress resistance, and the cognitive performance of the nematodes, emphasizing the protection against serotonergic synapse dysfunction. Furthermore, the treatment reduced the polyQ aggregates in the nematodes. The data described herein shed light on the connection between DHA and the cognitive performance in neurodegenerative diseases and demonstrated the potential of DHA-TG as nutritional co-adjuvant to prevent the development of polyQ-associated dysfunctions.

Influence of the Degree of Unsaturation in Fish Oil Supplements on Oxidative Stress and Protein Carbonylation in the Cerebral Cortex and Cerebellum of Healthy Rats

ω-3 polyunsaturated fatty acids (PUFAs) are crucial for brain structure and function, especially docosahexaenoic acid (DHA). However, an excess of DHA may increase lipid peroxidation due to its high degree of unsaturation, particularly in tissues highly susceptible to oxidative stress, such as the brain. Therefore, this study evaluated the effects of 10 weeks of dietary supplementation with fish oil containing 80% DHA on oxidative stress and the modulation of the carbonylated proteome in both the cerebral cortex and cerebellum of male Sprague Dawley rats. The results were compared with those induced by oils with a lower degree of fat unsaturation (fish oil containing 25% DHA and 25% eicosapentaenoic acid, soybean oil containing 50% linoleic acid and coconut oil containing 90% saturated fat). The results demonstrated that fish oil containing 80% DHA significantly increased the ω3/ω6 ratio in both the cortex and cerebellum while stimulating antioxidant defense by enhancing the reduced glutathione amount and decreasing the carbonylation of specific proteins, mainly those involved in glycolysis and neurotransmission. The majority of sensitive proteins in both brain regions followed this carbonylation trend (in decreasing order): soybean > EPA/DHA 1:1 > coconut > 80% DHA. The results also indicated that the cerebellum is more responsive than the cortex to changes in the cellular redox environment induced by varying degrees of fat unsaturation. In conclusion, under healthy conditions, dietary supplementation with fish oils containing high DHA levels makes the brain more resilient to potential oxidative insults compared to oils with lower DHA content and a lower degree of fatty acid unsaturation.

Unraveling the Omega-3 Puzzle: Navigating Challenges and Innovations for Bone Health and Healthy Aging

Omega-3 polyunsaturated fatty acids (ω-3 PUFAs, n-3 PUFAs), including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA), are essential polyunsaturated fats primarily obtained from fatty fish and plant-based sources. Compelling evidence from preclinical and epidemiological studies consistently suggests beneficial effects of ω-3 PUFAs on bone health and healthy aging processes. However, clinical trials have yielded mixed results, with some failing to replicate these benefits seen in preclinical models. This contraindication is mainly due to challenges such as low bioavailability, potential adverse effects with higher doses, and susceptibility to oxidation of ω-3 fatty acids, hindering their clinical effectiveness. This review comprehensively discusses recent findings from a clinical perspective, along with preclinical and epidemiological studies, emphasizing the role of ω-3 PUFAs in promoting bone health and supporting healthy aging. Additionally, it explores strategies to improve ω-3 PUFA efficacy, including nanoparticle encapsulation and incorporation of specialized pro-resolving mediators (SPM) derived from DHA and EPA, to mitigate oxidation and enhance solubility, thereby improving therapeutic potential. By consolidating evidence from various studies, this review underscores current insights and future directions in leveraging ω-3 PUFAs for therapeutic applications.

The effect of consuming nuts on cognitive function: a systematic review and meta-analysis of randomized clinical trials

Background

Results from clinical trials investigating the effect of nuts consumption on cognition are conflicting. We decided to conduct the current meta-analysis to summarize all available evidence on the effect of consuming nuts on cognition scores.

Methods

We conducted a comprehensive search in the online databases using relevant keywords up to June 2024. We included all the published Randomized clinical trials (RCTs) investigating the effect of nuts, compared to control, on cognition scores.

Results

Overall, 5 trials were included with a total sample size of 928 adults. Based on 6 effect sizes from these 5 trials, we did not find a significant effect of nuts on cognition function [Standardized Mean Difference (SMD): 0.27, 95% CI: -0.65 to 1.19, p = 0.57].

Conclusion

Our review could not find a significant effect of nuts on cognition function. Future high-quality RCTs with larger sample sizes should be conducted to shed light on the impact of nuts on cognition.

Impact of wall materials and DHA sources on the release, digestion and absorption of DHA microcapsules: Advancements, challenges and future directions

Docosahexaenoic acid (DHA), an essential omega-3 fatty acid, offers significant health benefits but faces challenges such as distinct odor, oxidation susceptibility, and limited intestinal permeability, hindering its broad application. Microencapsulation, widely employed, enhances DHA performance by facilitating controlled release, digestion, and absorption in the gastrointestinal tract. Despite extensive studies on DHA microcapsules and related delivery systems, understanding the mechanisms governing encapsulated DHA release, digestion, and absorption, particularly regarding the influence of wall materials and DHA sources, remains limited. This review starts with an overview of current techniques commonly applied for DHA microencapsulation. It then proceeds to outline up-to-date advances in the release, digestion and absorption of DHA microcapsules, highlighting the roles of wall materials and DHA sources. Importantly, it proposes strategies for overcoming challenges and exploiting opportunities to enhance the bioavailability of DHA microcapsules. Notably, spray drying dominates DHA microencapsulation (over 90 % usage), while complex coacervation shows promise for future applications. The combination of proteins and carbohydrates or phospholipids as wall material exhibits potential in controlling release and digestion of DHA microcapsules. The source of DHA, particularly algal oil, demonstrates higher lipid digestibility and absorptivity of free fatty acids (FFAs) than fish oil. Future advancements in DHA microcapsule development include formulation redesign (e.g., using plant proteins as wall material and algal oil as DHA source), technique optimization (such as co-microencapsulation and pre-digestion), and creation of advanced in vitro systems for assessing DHA digestion and absorption kinetics.

The Effect of Omega-3 Fatty Acid Supplementation and Exercise on Locomotor Activity, Exploratory Activity, and Anxiety-Like Behavior in Adult and Aged Rats

Aging is an inevitable and complex biological process that is associated with a gradual decline in physiological functions and a higher disease susceptibility. Omega-3 fatty acids, particularly docosahexaenoic acid, play a crucial role in maintaining brain health and their deficiency is linked to age-related cognitive decline. Combining omega-3-rich diets with exercise may enhance cognitive function more effectively, as both share overlapping neurobiological and physiological effects. This study aimed to evaluate the effect of exercise and omega-3 fatty acid (FA) supplementation in two different doses (160 mg/kg and 320 mg/kg) on anxiety-like behavior and cognitive abilities in both adult and aged rats. Male Wistar rats (4-5- and 23-24-month-old) were randomly divided into seven groups: 3-week control supplemented with placebo without exercise, low-dose omega-3 FAs, high-dose omega-3 FAs, 7-week control supplemented with placebo without exercise, exercise-only, low-dose omega-3 FAs with exercise, and high-dose omega-3 FAs with exercise. The administered oil contained omega-3 FAs with DHA:EPA in a ratio of 1.5:1. Our results indicate that aging negatively impacts the locomotor and exploratory activity of rats. In adult rats, a low dose of omega-3 FAs reduces locomotor activity when combined with exercise while high dose of omega-3 FAs reduces anxiety-like behavior and improves recognition memory when combined with exercise. The combination of omega-3 FAs and exercise had varying impacts on behavior, suggesting a need for further research in this area to fully understand their therapeutic efficacy in the context of cognitive changes associated with aging.

Nature's Toolbox for Alzheimer's Disease: A Review on the Potential of Natural Products as Alzheimer's Disease Drugs

Numerous clinical trials involving natural products have been conducted to observe cognitive performances and biomarkers in Alzheimer's Disease (AD) patients. However, to date, no natural-based drugs have been approved by the FDA as treatments for AD. In this review, natural product-based compounds that were tested in clinical trials from 2011 to 2023, registered at www.clinicaltrials.gov were reviewed. Thirteen compounds, encompassing 7 different mechanisms of action were covered. Several observations were deduced, which are: i) several compounds showed cognitive improvement, but these improvements may not extend to AD, ii) compounds that are endogenous to the human body showed better outcomes, and iii) Docosahexaenoic acid (DHA) and cerebrolysin had the most potential as AD drugs among the 13 compounds. Based on the current findings, natural products may be more suitable as a supplement than AD drugs in most cases. However, the studies covered here were conducted in a relatively short amount of time, where compounds acting on AD pathways may take time to show any effect. Given the diverse pathways that these natural products are involved in, they may potentially produce synergistic effects that would be beneficial in treating AD. Additionally, natural products benefit from both physicochemical properties being in more favorable ranges and active transport playing a more significant role than it does for synthetic compounds.

Bazi Bushen ameliorates age-related energy metabolism dysregulation by targeting the IL-17/TNF inflammatory pathway associated with SASP

BACKGROUND

Chronic inflammation and metabolic dysfunction are key features of systemic aging, closely associated with the development and progression of age-related metabolic diseases. Bazi Bushen (BZBS), a traditional Chinese medicine used to alleviate frailty, delays biological aging by modulating DNA methylation levels. However, the precise mechanism of its anti-aging effect remains unclear. In this study, we developed the Energy Expenditure Aging Index (EEAI) to estimate biological age. By integrating the EEAI with transcriptome analysis, we aimed to explore the impact of BZBS on age-related metabolic dysregulation and inflammation in naturally aging mice.

METHODS

We conducted indirect calorimetry analysis on five groups of mice with different ages and utilized the data to construct EEAI. 12 -month-old C57BL/6 J mice were treated with BZBS or β-Nicotinamide Mononucleotide (NMN) for 8 months. Micro-CT, Oil Red O staining, indirect calorimetry, RNA sequencing, bioinformatics analysis, and qRT-PCR were performed to investigate the regulatory effects of BZBS on energy metabolism, glycolipid metabolism, and inflammaging.

RESULTS

The results revealed that BZBS treatment effectively reversed the age-related decline in energy expenditure and enhanced overall metabolism, as indicated by the aging index of energy expenditure derived from energy metabolism parameters across various ages. Subsequent investigations showed that BZBS reduced age-induced visceral fat accumulation and hepatic lipid droplet aggregation. Transcriptomic analysis of perirenal fat and liver indicated that BZBS effectively enhanced lipid metabolism pathways, such as the PPAR signaling pathway, fatty acid oxidation, and cholesterol metabolism, and improved glycolysis and mitochondrial respiration. Additionally, there was a significant improvement in inhibiting the inflammation-related arachidonic acid-linoleic acid metabolism pathway and restraining the IL-17 and TNF inflammatory pathways activated via senescence associated secretory phenotype (SASP).

CONCLUSIONS

BZBS has the potential to alleviate inflammation in metabolic organs of naturally aged mice and maintain metabolic homeostasis. This study presents novel clinical therapeutic approaches for the prevention and treatment of age-related metabolic diseases.

Dietary Marine Oils Selectively Decrease Obesogenic Diet-Derived Carbonylation in Proteins Involved in ATP Homeostasis and Glutamate Metabolism in the Rat Cerebellum

The regular intake of diets high in saturated fat and sugars increases oxidative stress and has been linked to cognitive decline and premature brain aging. The cerebellum is highly vulnerable to oxidative stress and thus, obesogenic diets might be particularly detrimental to this tissue. However, the precise molecular mechanisms behind obesity-related brain damage are still not clear. Since protein carbonylation, a biomarker of oxidative stress, influences protein functions and is involved in metabolic control, the current investigation addressed the effect of long-term high-fat and high-sucrose diet intake on the cerebellum of Sprague-Dawley rats by deciphering the changes caused in the carbonylated proteome. The antioxidant effects of fish oil supplementation on cerebellar carbonylated proteins were also investigated. Lipid peroxidation products and carbonylated proteins were identified and quantified using immunoassays and 2D-LC-MS/MS in the cerebellum. After 21 weeks of nutritional intervention, the obesogenic diet selectively increased carbonylation of the proteins that participate in ATP homeostasis and glutamate metabolism in the cerebellum. Moreover, the data demonstrated that fish oil supplementation restrained carbonylation of the main protein targets oxidatively damaged by the obesogenic diet, and additionally protected against carbonylation of several other proteins involved in amino acid biosynthesis and neurotransmission. Therefore, dietary interventions with fish oils could help the cerebellum to be more resilient to oxidative damage. The results could shed some light on the effect of high-fat and high-sucrose diets on redox homeostasis in the cerebellum and boost the development of antioxidant-based nutritional interventions to improve cerebellum health.

Fish oil supplementation counteracts the effect of high-fat and high-sucrose diets on the carbonylated proteome in the rat cerebral cortex

High daily intake of saturated fats and refined carbohydrates, which often leads to obesity and overweight, has been associated with cognitive impairment, premature brain aging and the aggravation of neurodegenerative diseases. Although the molecular pathology of obesity-related brain damage is not fully understood, the increased levels of oxidative stress induced by the diet seem to be definitively involved. Being protein carbonylation determinant for protein activity and function and a main consequence of oxidative stress, this study aims to investigate the effect of the long-term high-fat and sucrose diet intake on carbonylated proteome of the cerebral cortex of Sprague-Dawley rats. To achieve this goal, the study identified and quantified the carbonylated proteins and lipid peroxidation products in the cortex, and correlated them with biometrical, biochemical and other redox status parameters. Results demonstrated that the obesogenic diet selectively increased oxidative damage of specific proteins that participate in fundamental pathways for brain function, i.e. energy production, glucose metabolism and neurotransmission. This study also evaluated the antioxidant properties of fish oil to counteract diet-induced brain oxidative damage. Fish oil supplementation demonstrated a stronger capacity to modulate carbonylated proteome in the brain cortex. Data indicated that fish oils did not just decrease carbonylation of proteins affected by the obesogenic diet, but also decreased the oxidative damage of other proteins participating in the same metabolic functions, reinforcing the beneficial effect of the supplement on those pathways. The results could help contribute to the development of successful nutritional-based interventions to prevent cognitive decline and promote brain health.

Precision Nutrition: The Hype Is Exceeding the Science and Evidentiary Standards Needed to Inform Public Health Recommendations for Prevention of Chronic Disease

As dietary guidance for populations shifts from preventing deficiency disorders to chronic disease risk reduction, the biology supporting such guidance becomes more complex due to the multifactorial risk profile of disease and inherent population heterogeneity in the diet-disease relationship. Diet is a primary driver of chronic disease risk, and population-based guidance should account for individual responses. Cascading effects on evidentiary standards for population-based guidance are not straightforward. Precision remains a consideration for dietary guidance to prevent deficiency through the identification of population subgroups with unique nutritional needs. Reducing chronic disease through diet requires greater precision in (a) establishing essential nutrient needs throughout the life cycle in both health and disease; (b) considering effects of nutrients and other food substances on metabolic, immunological, inflammatory, and other physiological responses supporting healthy aging; and (c) considering healthy eating behaviors. Herein we provide a template for guiding population-based eating recommendations for reducing chronic diseases in heterogenous populations.

Structured Docosahexaenoic Acid (DHA) Enhances Motility and Promotes the Antioxidant Capacity of Aged C. elegans

The human lifespan has increased over the past century; however, healthspans have not kept up with this trend, especially cognitive health. Among nutrients for brain function maintenance, long-chain omega-3 polyunsaturated fatty acids (ω-3 LCPUFA): DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) must be highlighted, particularly structured forms of EPA and DHA which were developed to improve bioavailability and bioactivity in comparison with conventional ω-3 supplements. This study aims to elucidate the effect of a structured triglyceride form of DHA (DHA-TG) on the healthspan of aged C. elegans. Using a thrashing assay, the nematodes were monitored at 4, 8, and 12 days of adulthood, and DHA-TG improved its motility at every age without affecting lifespan. In addition, the treatment promoted antioxidant capacity by enhancing the activity and expression of SOD (superoxide dismutase) in the nematodes. Lastly, as the effect of DHA-TG was lost in the DAF-16 mutant strain, it might be hypothesized that the effects of DHA need DAF-16/FOXO as an intermediary. In brief, DHA-TG exerted a healthspan-promoting effect resulting in both enhanced physical fitness and increased antioxidant defense in aged C. elegans. For the first time, an improvement in locomotive function in aged wild-type nematodes is described following DHA-TG treatment.

A Comparative Study about the Neuroprotective Effects of DHA-Enriched Phosphatidylserine and EPA-Enriched Phosphatidylserine against Oxidative Damage in Primary Hippocampal Neurons

Nerve damage caused by accumulated oxidative stress is one of the characteristics and main mechanisms of Alzheimer's disease (AD). Previous studies have shown that phosphatidylserine (PS) rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) plays a significant role in preventing and mitigating the progression of AD. However, whether DHA-PS and EPA-PS can directly protect primary hippocampal neurons against oxidative damage has not been studied. Here, the neuroprotective functions of DHA-PS and EPA-PS against H₂O₂/t-BHP-induced oxidative damage and the possible mechanisms were evaluated in primary hippocampal neurons. It was found that DHA-PS and EPA-PS could significantly improve cell morphology and promote the restoration of neural network structure. Further studies showed that both of them significantly alleviated oxidative stress-mediated mitochondrial dysfunction. EPA-PS significantly inhibited the phosphorylation of ERK, thus playing an anti-apoptotic role, and EPA-PS significantly increased the protein expressions of p-TrkB and p-CREB, thus playing a neuroprotective role. In addition, EPA-PS, rather than DHA-PS could enhance synaptic plasticity by increasing the expression of SYN, and both could significantly reduce the expression levels of p-GSK3β and p-Tau. These results provide a scientific basis for the use of DHA/EPA-enriched phospholipids in the treatment of neurodegenerative diseases, and also provide a reference for the development of related functional foods.

Impact of multidomain preventive strategies on functional brain connectivity in older adults with cognitive complaint: Subset from the Montpellier center of the ancillary MAPT-MRI study

Introduction

The impact of multi-domain preventive interventions on older adults, in particular on those with higher risk to develop Alzheimer's disease (AD), could be beneficial, as it may delay cognitive decline. However, the precise mechanism of such positive impact is not fully understood and may involve brain reserve and adaptability of brain functional connectivity (FC).

Methods

To determine the effect of multidomain interventions (involving physical activity, cognitive training, nutritional counseling alone or in combination with omega-3 fatty acid supplementation and vs. a placebo) on the brain, longitudinal FC changes were assessed after 36 months of intervention on 100 older adults (above 70 year-old) with subjective cognitive complaints.

Results

No global change in FC was detected after uni or multidomain preventive interventions. However, an effect of omega-3 fatty acid supplementation dependent on cognitive decline status was underlined for frontoparietal, salience, visual and sensorimotor networks FC. These findings were independent of the cortical thickness and vascular burden.

Discussion

These results emphasize the importance of patient stratification, based on risk factors, for preventive interventions.

Esterification of Docosahexaenoic Acid Enhances Its Transport to the Brain and Its Potential Therapeutic Use in Brain Diseases

Docosahexaenoic acid-containing lysophosphatidylcholine (DHA-LysoPC) is presented as the main transporter of DHA from blood plasma to the brain. This is related to the major facilitator superfamily domain-containing protein 2A (Mfsd2a) symporter expression in the blood-brain barrier that recognizes the various lyso-phospholipids that have choline in their polar head. In order to stabilize the DHA moiety at the sn-2 position of LysoPC, the sn-1 position was esterified by the shortest acetyl chain, creating the structural phospholipid 1-acetyl,2-docosahexaenoyl-glycerophosphocholine (AceDoPC). This small structure modification allows the maintaining of the preferential brain uptake of DHA over non-esterified DHA. Additional properties were found for AceDoPC, such as antioxidant properties, especially due to the aspirin-like acetyl moiety, as well as the capacity to generate acetylcholine in response to the phospholipase D cleavage of the polar head. Esterification of DHA within DHA-LysoPC or AceDoPC could elicit more potent neuroprotective effects against neurological diseases.