Blueberry Supplementation in Midlife for Dementia Risk Reduction

The state of the science on the health benefits of blueberries: a perspective

Mounting evidence indicates that blueberry consumption is associated with a variety of health benefits. It has been suggested that regular consumption of blueberries can support and/or protect against cardiovascular disease and function, pre-diabetes and type 2 diabetes, and brain and cognitive function in individuals with health conditions and age-related decline. Further, mechanistic investigations highlight the role of blueberry anthocyanins in mediating these health benefits, in part through interactions with gut microbiota. Also, nutritional interventions with blueberries have demonstrated the ability to improve recovery following exercise-induced muscle damage, attributable to anti-inflammatory effects. Despite these advancements in blueberry health research, research gaps persist which affects the generalizability of findings from clinical trials. To evaluate the current state of knowledge and research gaps, a blueberry health roundtable with scientific experts convened in Washington, DC (December 6-7, 2022). Discussions centered around five research domains: cardiovascular health, pre-diabetes and diabetes, brain health and cognitive function, gut health, and exercise recovery. This article synthesizes the outcomes of a blueberry research roundtable discussion among researchers in these domains, offering insights into the health benefits of blueberries and delineating research gaps and future research directions.

Influence of Bilberry Extract on Neuronal Cell Toxicity

Increased intake of dietary antioxidants such as anthocyanins, which are enriched in colourful fruits, is a promising alternative to reduce the risk of degenerative diseases such as Alzheimer's Disease (AD). Since Amyloid β (Aβ) is one of the key components contributing to AD pathology, probably by reactive oxygen species (ROS) induction, this study investigated the preventive effect of anthocyanin-rich bilberry extract (BE) and its anthocyanin fraction (ACN) on ROS generation and cell toxicity. The results showed a significant and concentration-dependent decrease in neuroblastoma cell (SH-SY5Y) viability by BE or ACN, whereas no cell toxicity was observed in HeLa cells. Incubation with BE and ACN for 24 h diminished the generation of induced ROS levels in SH-SY5Y and HeLa cells. In addition, low concentrations of BE (1-5 µg/mL) showed protective effects against Aβ-induced cytotoxicity in SH-SY5Y cells. In conclusion, our results suggest antioxidant and protective effects of BE and ACN, which could potentially be used to delay the course of neurodegenerative diseases such as AD. Further studies are needed to clarify the high potential of anthocyanins and their in vivo metabolites on neuronal function.

Hormetic Nutrition and Redox Regulation in Gut-Brain Axis Disorders

The antioxidant and anti-inflammatory effects of hormetic nutrition for enhancing stress resilience and overall human health have received much attention. Recently, the gut-brain axis has attracted prominent interest for preventing and therapeutically impacting neuropathologies and gastrointestinal diseases. Polyphenols and polyphenol-combined nanoparticles in synergy with probiotics have shown to improve gut bioavailability and blood-brain barrier (BBB) permeability, thus inhibiting the oxidative stress, metabolic dysfunction and inflammation linked to gut dysbiosis and ultimately the onset and progression of central nervous system (CNS) disorders. In accordance with hormesis, polyphenols display biphasic dose-response effects by activating at a low dose the Nrf2 pathway resulting in the upregulation of antioxidant vitagenes, as in the case of heme oxygenase-1 upregulated by hidrox® or curcumin and sirtuin-1 activated by resveratrol to inhibit reactive oxygen species (ROS) overproduction, microbiota dysfunction and neurotoxic damage. Importantly, modulation of the composition and function of the gut microbiota through polyphenols and/or probiotics enhances the abundance of beneficial bacteria and can prevent and treat Alzheimer's disease and other neurological disorders. Interestingly, dysregulation of the Nrf2 pathway in the gut and the brain can exacerbate selective susceptibility under neuroinflammatory conditions to CNS disorders due to the high vulnerability of vagal sensory neurons to oxidative stress. Herein, we aimed to discuss hormetic nutrients, including polyphenols and/or probiotics, targeting the Nrf2 pathway and vitagenes for the development of promising neuroprotective and therapeutic strategies to suppress oxidative stress, inflammation and microbiota deregulation, and consequently improve cognitive performance and brain health. In this review, we also explore interactions of the gut-brain axis based on sophisticated and cutting-edge technologies for novel anti-neuroinflammatory approaches and personalized nutritional therapies.

Chronic and postprandial effect of blueberries on cognitive function, alertness, and mood in participants with metabolic syndrome - results from a six-month, double-blind, randomized controlled trial

BACKGROUND

Anthocyanin and blueberry intakes positively associated with cognitive function in population-based studies and cognitive benefits in randomized controlled trials of adults with self-perceived or clinical cognitive dysfunction. To date, adults with metabolic syndrome (MetS) but without cognitive dysfunction are understudied.

OBJECTIVES

Cognitive function, mood, alertness, and sleep quality were assessed as secondary end points in MetS participants, postprandially (>24 h) and following 6-mo blueberry intake.

METHODS

A double-blind, randomized controlled trial was conducted, assessing the primary effect of consuming freeze-dried blueberry powder, compared against an isocaloric placebo, on cardiometabolic health >6 mo and a 24 h postprandial period (at baseline). In this secondary analysis of the main study, data from those completing mood, alertness, cognition, and sleep assessments are presented (i.e., n = 115 in the 6 mo study, n = 33 in the postprandial study), using the following: 1) Bond-Lader self-rated scores, 2) electronic cognitive battery (i.e., testing attention, working memory, episodic memory, speed of memory retrieval, executive function, and picture recognition), and 3) the Leeds Sleep Evaluation Questionnaire. Urinary and serum anthocyanin metabolites were quantified, and apolipoprotein E genotype status was determined.

RESULTS

Postprandial self-rated calmness significantly improved after 1 cup of blueberries (P = 0.01; q = 0.04; with an 11.6% improvement compared with baseline between 0 and 24 h for the 1 cup group), but all other mood, sleep, and cognitive function parameters were unaffected after postprandial and 6-mo blueberries. Across the ½ and 1 cup groups, microbial metabolites of anthocyanins and chlorogenic acid (i.e., hydroxycinnamic acids, benzoic acids, phenylalanine derivatives, and hippuric acids) and catechin were associated with favorable chronic and postprandial memory, attention, executive function, and calmness.

CONCLUSIONS

Although self-rated calmness improved postprandially, and significant cognition-metabolite associations were identified, our data did not support strong cognitive, mood, alertness, or sleep quality improvements in MetS participants after blueberry intervention. This trial was registered at clinicaltrials.gov as NCT02035592.

Effect of Polyphenol Supplementation on Memory Functioning in Overweight and Obese Adults: A Systematic Review and Meta-Analysis

Negative health consequences of obesity include impaired neuronal functioning and cell death, thus bringing the risk of impaired cognitive functioning. Antioxidant properties of polyphenols offer a possible intervention for overweight people, but evidence for their effectiveness in supporting cognitive functioning is mixed. This review examined evidence from randomized controlled trials concerning the effect of polyphenols on tasks requiring either immediate or delayed retrieval of learned information, respectively, thus controlling for differences in cognitive processes and related neural substrates supporting respective task demands. Searches of the PubMed/Medline, PsycInfo, and Scopus databases identified 24 relevant primary studies with N = 2336 participants having a BMI ≥ 25.0 kg/m2. The participants' mean age for the 24 studies exceeded 60 years. Respective meta-analyses produced a significant summary effect for immediate retrieval but not for delayed retrieval. The present findings support a potential positive effect of chronic supplementation with polyphenols, most notably flavonoids, on immediate retrieval in participants aged over 60 years with obesity being a risk factor for cognitive impairment. We recommend further investigation of this potential positive effect in participants with such risk factors. Future research on all populations should report the phenolic content of the supplementation administered and be specific regarding the cognitive processes tested.

Differential response of blueberry to the application of bacterial inoculants to improve yield, organoleptic qualities and concentration of bioactive compounds

The application of bacterial biofortifiers is an increasingly common technique. In recent years, some strains have been shown to improve the nutraceutical qualities of crops. This work analyses the impact of biofortification with 3 bacterial strains of the genera Rhizobium, Paenibacillus and Lactiplantibacillus on the nutritional characteristics and organic composition of blueberry in Portugal. Paenibacillus sp. VMFR46 treatment showed increase of 71.36 % and 79.88 % in total production. Biofortified treatments were able to increase Brix degree, maturity index (up to 48.05 % for cv. Legacy and up to 26.04 % for cv. Duke) and CIEL*a*b* index respect to uninoculated control. In this way, (poly)phenolic compounds concentration increased in biofortified treatment, and their (poly)phenolic profile was modified, some compounds such as myricetin aglycone or myricetin derivative are exclusive of the fruits from biofortified plants, with increases in (poly)phenolic concentrations related with R. laguerreae PEPV16 or Paenibacillus sp. VMFR46 inoculation in cv. Legacy. These modifications resulted in the improvement of the nutraceutical characteristics of the fruits obtained.

Anthocyanins: Molecular Aspects on Their Neuroprotective Activity

Anthocyanins are a type of flavonoids that give plants and fruits their vibrant colors. They are known for their potent antioxidant properties and have been linked to various health benefits. Upon consumption, anthocyanins are quickly absorbed and can penetrate the blood-brain barrier (BBB). Research based on population studies suggests that including anthocyanin-rich sources in the diet lower the risk of neurodegenerative diseases. Anthocyanins exhibit neuroprotective effects that could potentially alleviate symptoms associated with such diseases. In this review, we compiled and discussed a large body of evidence supporting the neuroprotective role of anthocyanins. Our examination encompasses human studies, animal models, and cell cultures. We delve into the connection between anthocyanin bioactivities and the mechanisms underlying neurodegeneration. Our findings highlight how anthocyanins' antioxidant, anti-inflammatory, and anti-apoptotic properties contribute to their neuroprotective effects. These effects are particularly relevant to key signaling pathways implicated in the development of Alzheimer's and Parkinson's diseases. In conclusion, the outcome of this review suggests that integrating anthocyanin-rich foods into human diets could potentially serve as a therapeutic approach for neurological conditions, and we identify promising avenues for further exploration in this area.

Early Intervention in Cognitive Aging with Strawberry Supplementation

Late-life dementia is a growing public health concern lacking effective treatment. Neurodegenerative disorders such as Alzheimer's disease (AD) develop over a preclinical period of many years beginning in midlife. The prevalence of insulin resistance, a prominent risk factor for late-life dementia, also accelerates in middle-age. Consumption of berry fruits, including strawberries, has been shown to influence metabolism as well as cognitive performance suggesting potential to mitigate risk for dementia. In this controlled trial, we enrolled overweight middle-aged men and women with insulin resistance and subjective cognitive decline and performed a 12-week intervention with daily administration of whole-fruit strawberry powder. Diet records showed that participants in both groups maintained the prescribed abstinence from berry product consumption outside the study. We observed diminished memory interference (p = 0.02; Cohen's f = 0.45) and a reduction of depressive symptoms (p = 0.04; Cohen's f = 0.39) for the strawberry-treated participants; benefits consistent with improved executive ability. However, there was no effect of the intervention on metabolic measures, possibly a consequence of the sample size, length of the intervention, or comparatively low anthocyanin dose. Anti-inflammatory actions of anthocyanins were considered as a primary mechanistic factor. The findings support the notion that strawberry supplementation has a role in dementia risk reduction when introduced in midlife. However, further investigation with longer intervention periods, larger samples, and differing dosing regimens will be required to assess the benefits of strawberry intake with respect to cognition and metabolic function in the context of aging.

A mixture of Nordic berries improves cognitive function, metabolic function and alters the gut microbiota in C57Bl/6J male mice

Our diets greatly influence our health. Multiple lines of research highlight the beneficial properties of eating berries and fruits. In this study, a berry mixture of Nordic berries previously identified as having the potential to improve memory was supplemented to young C57Bl/6J male mice to investigate effects on cognition function, metabolic health, markers of neuroinflammation, and gut microbiota composition. C57Bl/6J male mice at the age of 8 weeks were given standard chow, a high-fat diet (HF, 60%E fat), or a high-fat diet supplemented with freeze-dried powder (20% dwb) of a mixture of Nordic berries and red grape juice (HF + Berry) for 18 weeks (n = 12 animals/diet group). The results show that supplementation with the berry mixture may have beneficial effects on spatial memory, as seen by enhanced performance in the T-maze and Barnes maze compared to the mice receiving the high-fat diet without berries. Additionally, berry intake may aid in counteracting high-fat diet induced weight gain and could influence neuroinflammatory status as suggested by the increased levels of the inflammation modifying IL-10 cytokine in hippocampal extracts from berry supplemented mice. Furthermore, the 4.5-month feeding with diet containing berries resulted in significant changes in cecal microbiota composition. Analysis of cecal bacterial 16S rRNA revealed that the chow group had significantly higher microbial diversity, as measured by the Shannon diversity index and total operational taxonomic unit richness, than the HF group. The HF diet supplemented with berries resulted in a strong trend of higher total OTU richness and significantly increased the relative abundance of Akkermansia muciniphila, which has been linked to protective effects on cognitive decline. In conclusion, the results of this study suggest that intake of a Nordic berry mixture is a valuable strategy for maintaining and improving cognitive function, to be further evaluated in clinical trials.

Perspective: Challenges and Future Directions in Clinical Research with Nuts and Berries

Consumption of nuts and berries are considered part of a healthy eating pattern. Nuts and berries contain a complex nutrient profile consisting of essential vitamins and minerals, fiber, polyunsaturated fatty acids, and phenolics in quantities that improve physiological outcomes. The spectrum of health outcomes that may be impacted by the consumptions of nuts and berries includes cardiovascular, gut microbiome, and cognitive, among others. Recently, new insights regarding the bioactive compounds found in both nuts and berries have reinforced their role for use in precision nutrition efforts. However, challenges exist that can affect the generalizability of outcomes from clinical studies, including inconsistency in study designs, homogeneity of test populations, variability in test products and control foods, and assessing realistic portion sizes. Future research centered on precision nutrition and multi-omics technologies will yield new insights. These and other topics such as funding streams and perceived risk-of-bias were explored at an international nutrition conference focused on the role of nuts and berries in clinical nutrition. Successes, challenges, and future directions with these foods are presented here.

Blueberry Supplementation Effects on Neuronal and Pathological Biomarkers in Subjects at Risk for Alzheimer's Disease: A Pilot Study

Background

There is a need to develop non-invasive practical lifestyle interventions for preventing Alzheimer's disease (AD) in people at risk, such as those with mild cognitive impairment (MCI). Blueberry consumption has been associated with reduced risk of dementia in some epidemiologic studies and with improvements in cognition in healthy aging adults. Blood-based biomarkers have emerged at the forefront of AD therapeutics research spurred by the development of reliable ultra-sensitive "single-molecule array" assays with 100-1000-fold greater sensitivity over traditional platforms.

Objective

The purpose of this study was to examine the effect of blueberry supplementation in MCI on six blood biomarkers: amyloid-beta 40 (Aβ40), amyloid-beta 42 (Aβ42), phosphorylated Tau181 (ptau181), neurofilament light (NfL), Glial Fibrillary acidic protein (GFAP), and Brain-Derived Neurotrophic Factor (BDNF).

Methods

This was a 12-week, open-label, pilot trial of 10 participants with MCI (mean age 80.2 years + 5.16). Subjects consumed 36 grams per day of lyophilized blueberry powder in a split dose consumed with breakfast and dinner. Baseline and endpoint venous blood was analyzed using an ultrasensitive SIMOA assay. Our aim was to test if blueberry supplementation would particularly impact p-tau181, NfL, and GFAP elevations associated with the neurodegenerative process.

Results

There were no statistically significant (p < 0.05) changes from baseline to endpoint for any of the biomarker values or in the ratios of Aβ42 / Aβ40 and ptau181/ Aβ42. Adverse effects were mild and transient; supplementation was relatively well tolerated with all subjects completing the study.

Conclusion

To our knowledge, this is the first study to prospectively examine the effects of blueberry supplementation on a panel of blood biomarkers reflecting the neurodegenerative process. Our findings raise two possibilities - a potential stabilization of the neurodegenerative process or a lack of a direct and acute effect on beta-amyloid/tau/glial markers. A larger controlled study is warranted.

Polyphenol supplementation and executive functioning in overweight and obese adults at risk of cognitive impairment: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

Increasing evidence indicates a link between obesity and cognitive impairment. Furthermore, there is limited literature regarding the effect of polyphenols, a plant derived compounds, on executive functioning in an overweight/obese population at-risk of cognitive impairment. The aim of the present systematic review and meta-analysis of randomized controlled trials is to examine the effect of polyphenol supplementation on executive functions in overweight and/or obese populations at risk of cognitive impairment.

METHODS

A comprehensive literature search was conducted from inception to March 2023 using four electronic databases: PubMed/Medline, PsycInfo, Scopus and Cochrane trials library. Published primary research studies in English that compared the effect of polyphenols with placebo on executive function in overweight/obese adults were considered eligible for the meta-analysis. Jadad scale was used for the methodological quality rating of the included studies. Hedges g with 95% confidence intervals (CI) for endpoints were calculated using random effect model where applicable. Rosenthal's Fail-safe N, funnel plots, the Begg and Mazumdar's rank correlation test (Kendall's S statistic P-Q), Egger's linear regression test, and Duval and Tweedie's trim-and-fill test were identified for potential use as appropriate, to examine publication bias. Sensitivity analysis was conducted to examine the robustness of the results.

RESULTS AND CONCLUSION

A total of 23 RCT studies involving N = 1,976 participants were included in the review. The results of the meta-analysis revealed a non-significant effect for polyphenol supplementation on executive function (g = 0.076, CI = -0.018 to 0.170). Observations from primary studies within the meta-analysis showed a potential positive effect of polyphenol supplementation in a younger population at-risk of cognitive impairment and it is recommended to investigate this further in future studies. Moreover, the variability of the tasks used to examine executive functions as well as the adequate reporting of supplement's phenolic composition is a limitation that future work should also consider.

Effects of a polyphenol-rich grape and blueberry extract (Memophenol™) on cognitive function in older adults with mild cognitive impairment: A randomized, double-blind, placebo-controlled study

Background

Polyphenols are naturally occurring organic compounds found in plants. Research suggests that their intake reduces the risk of cognitive decline and related dementias. Grapes and blueberries are polyphenol-rich foods that have attracted attention for their potential cognitive-enhancing effects.

Purpose

Examine the effects of supplementation with a standardized and patented polyphenol-rich grape and blueberry extract (Memophenol™) on cognitive function in older adults with mild cognitive impairment.

Study design

Two-arm, 6 month, parallel-group, randomized, double-blind, placebo-controlled trial.

Methods

One hundred and forty-three volunteers aged 60 to 80 years with mild cognitive impairment were supplemented with either 150 mg of Memophenol™, twice daily or a placebo. Outcome measures included computer-based cognitive tasks, the Behavior Rating Inventory of Executive Function (BRIEF-A), the Cognitive Failures Questionnaire, and the CASP-19.

Results

Compared to the placebo, Memophenol™ supplementation was associated with greater improvements in the speed of information processing (p = 0.020), visuospatial learning (p = 0.012), and the BRIEF-A global score (p = 0.046). However, there were no other statistically significant between-group differences in the performance of other assessed cognitive tests or self-report questionnaires. Memophenol™ supplementation was well-tolerated with no reports of significant adverse reactions.

Conclusion

The promising results from this trial suggest that 6-months of supplementation with Memophenol™ may improve aspects of cognitive function in adults with mild cognitive impairment. Further research will be important to expand on the current findings and identify the potential mechanisms of action associated with the intake of this polyphenol-rich extract.

The Potential of Flavonoids and Flavonoid Metabolites in the Treatment of Neurodegenerative Pathology in Disorders of Cognitive Decline

Flavonoids are a biodiverse family of dietary compounds that have antioxidant, anti-inflammatory, antiviral, and antibacterial cell protective profiles. They have received considerable attention as potential therapeutic agents in biomedicine and have been widely used in traditional complimentary medicine for generations. Such complimentary medical herbal formulations are extremely complex mixtures of many pharmacologically active compounds that provide a therapeutic outcome through a network pharmacological effects of considerable complexity. Methods are emerging to determine the active components used in complimentary medicine and their therapeutic targets and to decipher the complexities of how network pharmacology provides such therapeutic effects. The gut microbiome has important roles to play in the generation of bioactive flavonoid metabolites retaining or exceeding the antioxidative and anti-inflammatory properties of the intact flavonoid and, in some cases, new antitumor and antineurodegenerative bioactivities. Certain food items have been identified with high prebiotic profiles suggesting that neutraceutical supplementation may be beneficially employed to preserve a healthy population of bacterial symbiont species and minimize the establishment of harmful pathogenic organisms. Gut health is an important consideration effecting the overall health and wellbeing of linked organ systems. Bioconversion of dietary flavonoid components in the gut generates therapeutic metabolites that can also be transported by the vagus nerve and systemic circulation to brain cell populations to exert a beneficial effect. This is particularly important in a number of neurological disorders (autism, bipolar disorder, AD, PD) characterized by effects on moods, resulting in depression and anxiety, impaired motor function, and long-term cognitive decline. Native flavonoids have many beneficial properties in the alleviation of inflammation in tissues, however, concerns have been raised that therapeutic levels of flavonoids may not be achieved, thus allowing them to display optimal therapeutic effects. Dietary manipulation and vagal stimulation have both yielded beneficial responses in the treatment of autism spectrum disorders, depression, and anxiety, establishing the vagal nerve as a route of communication in the gut-brain axis with established roles in disease intervention. While a number of native flavonoids are beneficial in the treatment of neurological disorders and are known to penetrate the blood–brain barrier, microbiome-generated flavonoid metabolites (e.g., protocatechuic acid, urolithins, γ-valerolactones), which retain the antioxidant and anti-inflammatory potency of the native flavonoid in addition to bioactive properties that promote mitochondrial health and cerebrovascular microcapillary function, should also be considered as potential biotherapeutic agents. Studies are warranted to experimentally examine the efficacy of flavonoid metabolites directly, as they emerge as novel therapeutic options.

The role of nutrition and the Mediterranean diet on the trajectories of cognitive decline

The worldwide burden of dementia is immense, and set to increase to unprecedented levels in the coming decades, due to population aging. In the absence of disease-modifying treatment, there is therefore a strong rationale to support the assumption that acting on modifiable risk factors, especially in midlife, is a good strategy for reducing the burden of dementia. Among these risk factors, nutrition is key, as it is fundamental to healthy aging, and has interrelated benefits on a number of organ systems, metabolic processes and health states that can all contribute to modifying the risk of dementia. In this paper, we review the methodological challenges of comparing studies of dietary interventions. We then discuss the effect of genetics and the environment on brain health, and review in particular the literature data on the effect of nutrition on cognition. We summarize the body of data reporting the largely beneficial effects of the Mediterranean diet on brain health, and the possible mechanisms that mediate these effects. Finally, we discuss future perspectives for further research in the field, notably the "gut-brain axis", thought to be a key mediator of the effect of nutrition on brain health.

A Randomised Placebo-Controlled Study of Purified Anthocyanins on Cognition in Individuals at Increased Risk for Dementia

IMPORTANCE

Identifying nutritional compounds which can reduce cognitive decline in older people is a hugely important topic.

OBJECTIVE

To study the safety and effect of anthocyanins in maintaining cognitive functioning in people at increased risk for dementia.

DESIGN, SETTING, AND PARTICIPANTS

Participants (206 individuals, aged 60-80 years) diagnosed with either mild cognitive impairment (MCI) or two or more cardiometabolic disorders (i.e., diabetes, hypertension, obesity) were enrolled at three different centres in Norway.

INTERVENTION

Participants were randomly assigned to four capsules with a total of 320 mg/d of naturally purified anthocyanins or placebo 1:1 for 24 weeks.

MAIN OUTCOMES AND MEASURES

The primary outcome was the Quality of Episodic Memory composite measure (0-100) from an online cognitive test battery CogTrack, which was administered at baseline and monthly for the next 24 weeks. Secondary outcomes included other cognitive scores from the CogTrack battery. We applied mixed effects models with a baseline test score, group, time and their interaction as fixed effects, as well as other predefined baseline covariates. The primary comparison was the group difference at week 24 based on a modified intention-to-treat principle.

RESULTS

The primary analysis did not show a significant group difference at 24 weeks (78.2 versus 76.8; adjusted mean difference 1.4 (95% confidence interval -0.9-3.7); effect size 0.15; p = 0.23). However, there was a significant difference in slopes during weeks 8-24 (p = 0.007); the anthocyanin group improved while the placebo group worsened. No differences were found for the secondary cognitive outcomes. Anthocyanin capsules were well-tolerated and safe to use.

CONCLUSION

Anthocyanin supplementation for 24 weeks was safe and well tolerated in people with MCI or cardiometabolic disorders. We found no significant group difference in episodic memory at the end of the study but statistically significant differences in slopes. Further studies are warranted to explore whether anthocyanins supplementation can reduce cognitive decline in people at increased risk of dementia.

TRIAL REGISTRATION

ClinicalTrials.gov, (Identifier NCT03419039). http://www.

CLINICALTRIALS

gov/, NCT03419039.

Complementary and Alternative Medicine Approaches in Alzheimer Disease and Other Neurocognitive Disorders

As our population ages, there is interest in delaying or intervening in cognitive decline. While newer agents are under development, agents in mainstream use do not impact the course of diseases that cause cognitive decline. This increases interest in alternative strategies. Even as we welcome possible new disease-modifying agents, they are likely to remain costly. Herein, we review the evidence behind other complementary and alternative strategies for cognitive enhancement and prevention of cognitive decline.

Benefits of dietary polyphenols in Alzheimer's disease

Alzheimer's disease (AD) is an irreversible progressive neurodegenerative disease affecting approximately 50 million people worldwide. It is estimated to reach 152 million by the year 2050. AD is the fifth leading cause of death among Americans age 65 and older. In spite of the significant burden the disease imposes upon patients, their families, our society, and our healthcare system, there is currently no cure for AD. The existing approved therapies only temporarily alleviate some of the disease's symptoms, but are unable to modulate the onset and/or progression of the disease. Our failure in developing a cure for AD is attributable, in part, to the multifactorial complexity underlying AD pathophysiology. Nonetheless, the lack of successful pharmacological approaches has led to the consideration of alternative strategies that may help delay the onset and progression of AD. There is increasing recognition that certain dietary and nutrition factors may play important roles in protecting against select key AD pathologies. Consistent with this, select nutraceuticals and phytochemical compounds have demonstrated anti-amyloidogenic, antioxidative, anti-inflammatory, and neurotrophic properties and as such, could serve as lead candidates for further novel AD therapeutic developments. Here we summarize some of the more promising dietary phytochemicals, particularly polyphenols that have been shown to positively modulate some of the important AD pathogenesis aspects, such as reducing β-amyloid plaques and neurofibrillary tangles formation, AD-induced oxidative stress, neuroinflammation, and synapse loss. We also discuss the recent development of potential contribution of gut microbiome in dietary polyphenol function.

Employ of Anthocyanins in Nanocarriers for Nano Delivery: In Vitro and In Vivo Experimental Approaches for Chronic Diseases

Anthocyanins are among the best-known phenolic compounds and possess remarkable biological activities, including antioxidant, anti-inflammatory, anticancer, and antidiabetic effects. Despite their therapeutic benefits, they are not widely used as health-promoting agents due to their instability, low absorption, and, thus, low bioavailability and rapid metabolism in the human body. Recent research suggests that the application of nanotechnology could increase their solubility and/or bioavailability, and thus their biological potential. Therefore, in this review, we have provided, for the first time, a comprehensive overview of in vitro and in vivo studies on nanocarriers used as delivery systems of anthocyanins, and their aglycones, i.e., anthocyanidins alone or combined with conventional drugs in the treatment or management of chronic diseases.