Blueberry supplementation improves memory in older adults

Polyphenols and the human brain: plant “secondary metabolite” ecologic roles and endogenous signaling functions drive benefits

Flavonoids and other polyphenols are ubiquitous plant chemicals that fulfill a range of ecologic roles for their home plant, including protection from a range of biotic and abiotic stressors and a pivotal role in the management of pathogenic and symbiotic soil bacteria and fungi. They form a natural part of the human diet, and evidence suggests that their consumption is associated with the beneficial modulation of a number of health-related variables, including those related to cardiovascular and brain function. Over recent years, the consensus as to the mechanisms responsible for these effects in humans has shifted away from polyphenols having direct antioxidant effects and toward their modulation of cellular signal transduction pathways. To date, little consideration has been given to the question of why, rather than how, these plant-derived chemicals might exert these effects. Therefore, this review summarizes the evidence suggesting that polyphenols beneficially affect human brain function and describes the current mechanistic hypotheses explaining these effects. It then goes on to describe the ecologic roles and potential endogenous signaling functions that these ubiquitous phytochemicals play within their home plant and discusses whether these functions drive their beneficial effects in humans via a process of “cross-kingdom” signaling predicated on the many conserved similarities in plant, microbial, and human cellular signal transduction pathways.

Impact of processing on the bioavailability and vascular effects of blueberry (poly)phenols

SCOPE

Blueberries are a rich source of flavonoids and phenolic acids. Currently, little information is available regarding the impact of processing on the bioavailability and the bioactivity of blueberry (poly)phenols.

METHODS AND RESULTS

In a randomized, controlled crossover trial, ten healthy volunteers consumed (a) blueberry-containing baked products, (b) an unprocessed blueberry drink containing the same amount of freeze-dried blueberry powder as used in the baked products, and (c) matched control baked products. Endothelial function was measured as flow-mediated dilation (FMD) and plasma samples taken at baseline and at 1, 2, 4, and 6 h postconsumption. Although processing did not significantly change the total (poly)phenolic amount, the processed products contained significantly less anthocyanins (-42%), more chlorogenic acid (23%), no flavanol nonamers or decamers, and significantly more flavanol dimers and trimers (36% and 28%, respectively). FMD increased after 1, 2, and 6 h consumption of the baked products to a similar degree as the unprocessed blueberries, despite significant differences in the levels of individual plasma metabolites. No changes were observed after the consumption of the control product.

CONCLUSION

Careful processing can preserve important biological activities of blueberries despite changing the blueberry (poly)phenol composition and plasma metabolite profile.

Anti-inflammatory effect of the blueberry anthocyanins malvidin-3-glucoside and malvidin-3-galactoside in endothelial cells

Blueberry fruits have a wide range of health benefits because of their abundant anthocyanins, which are natural antioxidants. The purpose of this study was to investigate the inhibitory effect of blueberry's two main anthocyanins (malvidin-3-glucoside and malvidin-3-galactoside) on inflammatory response in endothelial cells. These two malvidin glycosides could inhibit tumor necrosis factor-alpha (TNF-α) induced increases of monocyte chemotactic protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) production both in the protein and mRNA levels in a concentration-dependent manner. Mv-3-glc at the concentration of 1 μM could inhibit 35.9% increased MCP-1, 54.4% ICAM-1, and 44.7% VCAM-1 protein in supernatant, as well as 9.88% MCP-1 and 48.6% ICAM-1 mRNA expression (p<0.05). In addition, they could decrease IκBα degradation (Mv-3-glc, Mv-3-gal, and their mixture at the concentration of 50 μM had the inhibition rate of 84.8%, 75.3%, and 43.2%, respectively, p<0.01) and block the nuclear translocation of p65, which suggested their anti-inflammation mechanism was mediated by the nuclear factor-kappa B (NF-κB) pathway. In general malvidin-3-glucoside had better anti-inflammatory effect than malvidin-3-galactoside. These results indicated that blueberry is good resource of anti-inflammatory anthocyanins, which can be promising molecules for the development of nutraceuticals to prevent chronic inflammation in many diseases.

Neuroprotective effects of berry fruits on neurodegenerative diseases

Recent clinical research has demonstrated that berry fruits can prevent age-related neurodegenerative diseases and improve motor and cognitive functions. The berry fruits are also capable of modulating signaling pathways involved in inflammation, cell survival, neurotransmission and enhancing neuroplasticity. The neuroprotective effects of berry fruits on neurodegenerative diseases are related to phytochemicals such as anthocyanin, caffeic acid, catechin, quercetin, kaempferol and tannin. In this review, we made an attempt to clearly describe the beneficial effects of various types of berries as promising neuroprotective agents.

Antioxidant activity and acetylcholinesterase inhibition of grape skin anthocyanin (GSA)

We aimed to investigate the antioxidant and acetylcholinesterase inhibitory activities of the anthocyanin rich extract of grape skin. Grape skin anthocyanin (GSA) neutralized free radicals in different test systems, such as 2,-2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays, to form complexes with Fe²⁺ preventing 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced erythrocyte hemolysis and oxidative DNA damage. Moreover, GSA decreased reactive oxygen species (ROS) generation in isolated mitochondria thus inhibiting 2',-7'-dichlorofluorescin (DCFH) oxidation. In an in vivo study, female BALB/c mice were administered GSA, at 12.5, 25, and 50 mg per kg per day orally for 30 consecutive days. Herein, we demonstrate that GSA administration significantly elevated the level of antioxidant enzymes in mice sera, livers, and brains. Furthermore, GSA inhibited acetylcholinesterase (AChE) in the in vitro assay with an IC₅₀ value of 363.61 µg/mL. Therefore, GSA could be an excellent source of antioxidants and its inhibition of cholinesterase is of interest with regard to neurodegenerative disorders such as Alzheimer’s disease.

Cognition: the new frontier for nuts and berries

The inclusion of nuts in the diet is associated with a decreased risk of coronary artery disease, hypertension, gallstones, diabetes, cancer, metabolic syndrome, and visceral obesity. Frequent consumption of berries seems to be associated with improved cardiovascular and cancer outcomes, improved immune function, and decreased recurrence of urinary tract infections; the consumption of nuts and berries is associated with reduction in oxidative damage, inflammation, vascular reactivity, and platelet aggregation, and improvement in immune functions. However, only recently have the effects of nut and berry consumption on the brain, different neural systems, and cognition been studied. There is growing evidence that the synergy and interaction of all of the nutrients and other bioactive components in nuts and berries can have a beneficial effect on the brain and cognition. Regular nut consumption, berry consumption, or both could possibly be used as an adjunctive therapeutic strategy in the treatment and prevention of several neurodegenerative diseases and age-related brain dysfunction. A number of animal and a growing number of human studies show that moderate-duration dietary supplementation with nuts, berry fruit, or both is capable of altering cognitive performance in humans, perhaps forestalling or reversing the effects of neurodegeneration in aging.

Nutraceuticals in cognitive impairment and Alzheimer's disease

Several chemical substances belonging to classes of natural dietary origin display protective properties against some age-related diseases including neurodegenerative ones, particularly Alzheimer's disease (AD). These compounds, known as nutraceuticals, differ structurally, act therefore at different biochemical and metabolic levels and have shown different types of neuroprotective properties. The aim of this review is to summarize data from observational studies, clinical trials, and randomized clinical trials (RCTs) in humans on the effects of selected nutraceuticals against age-related cognitive impairment and dementia. We report results from studies on flavonoids, some vitamins and other natural substances that have been studied in AD and that might be beneficial for the maintenance of a good cognitive performance. Due to the substantial lack of high-level evidence studies there is no possibility for recommendation of nutraceuticals in dementia-related therapeutic guidelines. Nevertheless, the strong potential for their neuroprotective action warrants further studies in the field.

Impact of cooking, proving, and baking on the (poly)phenol content of wild blueberry

Accumulating evidence suggests that diets rich in (poly)phenols may have positive effects on human health. Currently there is limited information regarding the effects of processing on the (poly)phenolic content of berries, in particular in processes related to the baking industry. This study investigated the impact of cooking, proving, and baking on the anthocyanin, procyanidin, flavonol, and phenolic acid contents of wild blueberry using HPLC with UV and fluorescence detection. Anthocyanin levels decreased during cooking, proving, and baking, whereas no significant changes were observed for total procyanidins. However, lower molecular weight procyanidins increased and high molecular weight oligomers decreased during the process. Quercetin and ferulic and caffeic acid levels remained constant, whereas increases were found for chlorogenic acid. Due to their possible health benefits, a better understanding of the impact of processing is important to maximize the retention of these phytochemicals in berry-containing products.

Fruit quality, anthocyanin and total phenolic contents, and antioxidant activities of 45 blueberry cultivars grown in Suwon, Korea

Blueberry fruits from 45 commercial cultivars (39 northern highbush and 6 half highbush blueberry) grown in Suwon, Korea were analyzed for fruit size, soluble solids content, titratable acidity, total anthocyanin content, total phenolic content, and antioxidant activity. Fruit characteristics varied widely among the 45 blueberry cultivars. Fruit weight ranged from 0.9 to 3.6 g, soluble solids content from 8.3 to 14.3 °Brix, and titratable acidity from 0.8% to 3.6%. Antioxidant activity ranged from 0.7 to 2.1 mg of quercetin equivalents per gram of fresh berries in different blueberry cultivars. Among the 45 blueberry cultivars, high amounts of anthocyanins and polyphenols, and high antioxidant activity were observed in 'Elliott', 'Rubel', 'Rancocas', and 'Friendship'.

Biology of ageing and role of dietary antioxidants

Interest in relationship between diet and ageing is growing. Research has shown that dietary calorie restriction and some antioxidants extend lifespan in various ageing models. On the one hand, oxygen is essential to aerobic organisms because it is a final electron acceptor in mitochondria. On the other hand, oxygen is harmful because it can continuously generate reactive oxygen species (ROS), which are believed to be the factors causing ageing of an organism. To remove these ROS in cells, aerobic organisms possess an antioxidant defense system which consists of a series of enzymes, namely, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR). In addition, dietary antioxidants including ascorbic acid, vitamin A, vitamin C, α-tocopherol, and plant flavonoids are also able to scavenge ROS in cells and therefore theoretically can extend the lifespan of organisms. In this connection, various antioxidants including tea catechins, theaflavins, apple polyphenols, black rice anthocyanins, and blueberry polyphenols have been shown to be capable of extending the lifespan of fruit flies. The purpose of this review is to brief the literature on modern biological theories of ageing and role of dietary antioxidants in ageing as well as underlying mechanisms by which antioxidants can prolong the lifespan with focus on fruit flies as an model.

Effect of flavonoids on learning, memory and neurocognitive performance: relevance and potential implications for Alzheimer's disease pathophysiology

Recent evidence has indicated that a group of plant-derived compounds known as flavonoids may exert particularly powerful actions on mammalian cognition and may reverse age-related declines in memory and learning. In addition, growing evidence is also suggestive that flavonoids may delay the development of Alzheimer's disease-like pathology, suggestive of potential dietary strategies in dementia. Although these low-molecular-weight phytochemicals are absorbed to only a limited degree, they have been found to counteract age-related cognitive declines possibly via their ability to interact with the cellular and molecular architecture of the brain responsible for memory. However, the majority of the research has been carried out at rather supraphysiological concentrations and only a few studies have investigated the neuromodulatory effects of physiologically attainable flavonoid concentrations. This review will summarize the evidence for the effects of flavonoids and their metabolites in age-related cognitive decline and Alzheimer's disease. Mechanisms of actions will be discussed and include those activating signalling pathways critical in controlling synaptic plasticity, reducing neuroinflammation and inducing vascular effects potentially capable of causing new nerve cell growth in the hippocampus. Altogether, these processes are known to be important in maintaining optimal neuronal function, to limit neurodegeneration and to prevent or reverse age-dependent deteriorations in cognitive performance.

Berry antioxidants: small fruits providing large benefits

Small berry fruits are consumed because of their attractive colour and special taste, and are considered one of the richest sources of natural antioxidants. Their consumption has been linked to the prevention of some chronic and degenerative diseases. The term 'berry fruits' encompasses the so-called 'soft fruits', primarily strawberry, currants, gooseberry, blackberry, raspberry, blueberry and cranberry. The objective of this review is to highlight the nutraceutical value of berries and to summarize the factors affecting berry fruit antioxidants. Particular attention is given to postharvest and processing operation factors that may affect fruit phytochemical content. The structure-antioxidant relationships for phenolic compounds - the main group of antioxidants in this fruit group - are presented and major areas for future research are identified.

Neuroprotective effect of anthocyanins on acetylcholinesterase activity and attenuation of scopolamine-induced amnesia in rats

Anthocyanins are a group of natural phenolic compounds responsible for the color to plants and fruits. These compounds might have beneficial effects on memory and have antioxidant properties. In the present study we have investigated the therapeutic efficacy of anthocyanins in an animal model of cognitive deficits, associated to Alzheimer's disease, induced by scopolamine. We evaluated whether anthocyanins protect the effects caused by SCO on nitrite/nitrate (NOx) levels and Na(+),K(+)-ATPase and Ca(2+)-ATPase and acetylcholinesterase (AChE) activities in the cerebral cortex and hippocampus (of rats. We used 4 different groups of animals: control (CTRL), anthocyanins treated (ANT), scopolamine-challenged (SCO), and scopolamine+anthocyanins (SCO+ANT). After seven days of treatment with ANT (200mgkg(-1); oral), the animals were SCO injected (1mgkg(-1); IP) and were performed the behavior tests, and submitted to euthanasia. A memory deficit was found in SCO group, but ANT treatment prevented this impairment of memory (P<0.05). The ANT treatment per se had an anxiolytic effect. AChE activity was increased in both in cortex and hippocampus of SCO group, this effect was significantly attenuated by ANT (P<0.05). SCO decreased Na(+),K(+)-ATPase and Ca(2+)-ATPase activities in hippocampus, and ANT was able to significantly (P<0.05) prevent these effects. No significant alteration was found on NOx levels among the groups. In conclusion, the ANT is able to regulate cholinergic neurotransmission and restore the Na(+),K(+)-ATPase and Ca(2+)-ATPase activities, and also prevented memory deficits caused by scopolamine administration.

A role for hippocampal PSA-NCAM and NMDA-NR2B receptor function in flavonoid-induced spatial memory improvements in young rats

The increase in incidence and prevalence of neurodegenerative diseases highlights the need for a more comprehensive understanding of how food components may affect neural systems. In particular, flavonoids have been recognized as promising agents capable of influencing different aspects of synaptic plasticity resulting in improvements in memory and learning in both animals and humans. Our previous studies highlight the efficacy of flavonoids in reversing memory impairments in aged rats, yet little is known about the effects of these compounds in healthy animals, particularly with respect to the molecular mechanisms by which flavonoids might alter the underlying synaptic modifications responsible for behavioral changes. We demonstrate that a 3-week intervention with two dietary doses of flavonoids (Dose I: 8.7 mg/day and Dose II: 17.4 mg/day) facilitates spatial memory acquisition and consolidation (24 recall) (p < 0.05) in young healthy rats. We show for the first time that these behavioral improvements are linked to increased levels in the polysialylated form of the neural adhesion molecule (PSA-NCAM) in the dentate gyrus (DG) of the hippocampus, which is known to be required for the establishment of durable memories. We observed parallel increases in hippocampal NMDA receptors containing the NR2B subunit for both 8.7 mg/day (p < 0.05) and 17.4 mg/day (p < 0.001) doses, suggesting an enhancement of glutamate signaling following flavonoid intervention. This is further strengthened by the simultaneous modulation of hippocampal ERK/CREB/BDNF signaling and the activation of the Akt/mTOR/Arc pathway, which are crucial in inducing changes in the strength of hippocampal synaptic connections that underlie learning. Collectively, the present data supports a new role for PSA-NCAM and NMDA-NR2B receptor on flavonoid-induced improvements in learning and memory, contributing further to the growing body of evidence suggesting beneficial effects of flavonoids in cognition and brain health.

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We have identified novel targets for the flavonoid actions in the brain.

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Flavonoid ingestion facilitates hippocampal-dependent learning in healthy animals.

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Flavonoids regulate hippocampal PSA-NCAM in the Dentate Gyrus of the hippocampus.

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Flavonoids modulate the levels of hippocampal glutamate receptors (NMDA-NR2B).

The potential role of fruit and vegetables in aspects of psychological well-being: a review of the literature and future directions

The objective of the present paper was to review the literature investigating the potential relationship between fruit and vegetables (FV) and psychological well-being. The rising prevalence of mental ill health is causing considerable societal burden. Inexpensive and effective strategies are therefore required to improve the psychological well-being of the population, and to reduce the negative impact of mental health problems. A growing body of literature suggests that dietary intake may have the potential to influence psychological well-being. For example, studies have suggested that particular dietary constituents, including vitamins and minerals, might be beneficial to psychological health. However, in order to better reflect normal dietary intake, health-based research has increasingly begun to focus on whole foods and dietary patterns, rather than individual nutrients. One food group that has received increasing attention with regard to psychological health is FV. This is probably a result of the strong evidence base, which exists in relation to their protective association with a number of chronic diseases, as well as the fact that they are a rich source of some of the nutrients which have been linked to psychological health. While some promising findings exist with regards to FV intake and psychological well-being, overall, results are inconsistent. Possible reasons for this, such as methodological issues related to study design and the measurement of psychological well-being and FV intake, are discussed within this review. Based on the predominantly observational nature of existing literature, the present paper concludes that future well-designed randomised controlled trials are required to investigate the relationship further.

Effects of anthocyanins on active avoidance test of rats exposed to disruption of diurnal rhythm

The present study was undertaken to assess the effects of the natural antioxidant anthocyanins on learning and memory of rats in experimental model of oxidative stress. Our preliminary experiments demonstrated that disruption of diurnal rhythm via exposition of rats to constant light for 14 days caused excessive generation of free radicals in their brains. It is known that free radicals impair cognitive functions. This study investigated the effects of anthocyanins on cognitive functions of rats in a shuttle-box active avoidance test. In the shuttle-box, stressed rats showed significantly increased latency time and decreased number of avoidances and escapes in the learning sessions. Rats treated with anthocyanins had increased number of avoidances and escapes and significantly decreased latency time during the learning sessions. Our results demonstrated that this model of oxidative stress impaired learning and memory of experimental rats. Moreover, chronic administration of anthocyanins (200 mg/kg orally) improved brain functions of the rats. Our data suggest that anthocyanins have a protective role on rat brain and improve cognitive functions in this model of oxidative stress.

The antioxidant level of Alaska's wild berries: high, higher and highest

BACKGROUND

In the last few years, antioxidants have become the stars of the nutritional world. Antioxidants are important in terms of their ability to protect against oxidative cell damage that can lead to conditions, such as Alzheimer's disease, cancer and heart disease--conditions also linked with chronic inflammation. The antioxidant and anti-inflammatory effects of Alaska's wild berries may have the potential to help prevent these diseases.

OBJECTIVE

To discover the antioxidant levels of Alaska wild berries and the ways these antioxidant levels translate when preservation methods are applied to the berry.

DESIGN

This research centred on both the raw berries and products made from the berries. In the first year, a variety of wild berries were tested to discover their oxygen radical absorption capacity (ORAC) in the raw berries. The second level of the research project processed 4 different berries--blueberries, lingonberries, salmonberries, highbush cranberries--into 8 or 9 products made from these berries. The products were tested for both ORAC as well as specific antioxidants.

RESULTS

The Alaska wild berries collected and tested in the first experiment ranged from 3 to 5 times higher in ORAC value than cultivated berries from the lower 48 states. For instance, cultivated blueberries have an ORAC scale of 30. Alaska wild dwarf blueberries measure 85. This is also higher than lower 48 wild blueberries, which had a score of 61. All of the Alaskan berries tested have a level of antioxidant considered nutritionally valuable, ranging from 19 for watermelon berries to 206 for lingonberries on the ORAC scale. With the processed products made from 4 Alaska wild berries, one of the unexpected outcomes of the research was that the berries continued to have levels of antioxidants considered high, despite the effects of commonly used heat-processing techniques. When berries were dehydrated, per gram ORAC values increased.

CONCLUSION

Alaska wild berries have extraordinarily high antioxidant levels. Though cooking lowered the antioxidant level, and adding ingredients such as sugar diluted the antioxidant concentration, products made from berries are high sources of antioxidants.

A diet based on multiple functional concepts improves cognitive performance in healthy subjects

Background

Disorders such as the metabolic syndrome (MetS), impaired glucose tolerance and diabetes, are associated with increased risk of cognitive decline. Also several of the individual key features that define the MetS, e.g. hypertension, impaired glucose regulation, dyslipidemia, obesity, and inflammation, are related to an increased risk of cognitive decline. Consequently, a diet that prevents metabolic disorders might be expected to prevent cognitive decline. The purpose of the present study was to, in overweight but otherwise healthy subjects, investigate effects on cognitive functions of a dietary regime combining multiple functional concepts potentially beneficial to risk markers associated with MetS. The purpose was in addition to evaluate cognitive performance in relation to results on cardiometabolic risk variables (BMI, blood pressure, glucose, insulin, cholesterol, triglycerides, free fatty acids, lipoprotein A-1 and B, hs-CRP, HbA1c, interleukin-6, TNF-α, and PAI-1).

Methods

Fourty-four healthy women and men (50–73 years, BMI 25–33, fasting glycemia ≤ 6.1 mmol/L) participated in a randomized, controlled crossover intervention, comparing a multifunctional diet (active diet (AD)) including foods with a potential anti-inflammatory action, with a control diet (CD) devoid of the “active” components. Both diets were composed in close agreement with the Nordic dietary recommendations. Each diet was consumed during 4 wk, separated by a 4 wk washout period. Cognitive tests were performed at fasting and in the postprandial period after a standardized breakfast, after each diet period.

Results

In comparison with the CD, the AD improved performance in the Rey Auditory-Verbal Learning test (recognition test, p < 0.05, ANOVA, n = 42) and significantly improved performance in test of selective attention, which also included aspects of working memory (p < 0.05, n = 40). Performance in cognitive tests was inversely associated with plasma concentrations of cardiometabolic risk markers (fasting cholesterol, blood glucose, blood pressure) and cardiovascular risk scores (Framingham and Reynols), and positivly associated with apolipoprotein A1 (p < 0.05).

Conclusions

The results indicate that diet characteristics may modulate cognitive performance. A relationship seems to exist between cardiometabolic risk markers and cognitive performance in apparently healthy subjects. The results provide additional motives for diet based prevention of metabolic disturbances related to the MetS.

Evaluation of anthocynin changes in blueberries and in blueberry jam after the processing and storage

Blueberry (Vaccinium corymbosum L.) is worldwide famous as the healthy and desirable fruit. The most valuable nutritional components of fruits are polyphenols, which include anthocyanins. The aim of the study was to assess the content of anthocyanin dyes in selected varieties of blueberry fruit. We evaluated the changes in the content of colorants that occur after treatment for fruit jam and its subsequent storage at 21°C under the light. Varieties Ramcocas, Record, Iranka, Nelson, Pemberton, Jersey and Coville were observed. Content of anthocyanins was determined spectrophotometrically. In fresh fruits anthocyanin content ranged from 9.878 g kg-1 of dry matter (Jersey variety) to 18.555 g kg-1 of dry matter (Nelson variety). After treatment there was found a decrease in the anthocyanins content, in the product's content were determined in the amount 1.645 g kg-1 of dry matter (Jersey variety) to 3.476 g kg-1 of dry matter (variety Ramcocas). The decrease was due to decomposition of anthocyans at high temperatures in processed products and also by the replacement of dry matter by sucrose in the product. Mean color decrease in blueberry jam was 84.5%. After storage of the product, there were found further degradations of colorants, evaluated at 34.9%. The content of anthocyanin in jam was found to be 1.089 g kg-1 of dry matter (Jersey variety) to 2.199 g kg-1 of dry matter (Ramcocas variety).

Dietary levels of pure flavonoids improve spatial memory performance and increase hippocampal brain-derived neurotrophic factor

Evidence suggests that flavonoid-rich foods are capable of inducing improvements in memory and cognition in animals and humans. However, there is a lack of clarity concerning whether flavonoids are the causal agents in inducing such behavioral responses. Here we show that supplementation with pure anthocyanins or pure flavanols for 6 weeks, at levels similar to that found in blueberry (2% w/w), results in an enhancement of spatial memory in 18 month old rats. Pure flavanols and pure anthocyanins were observed to induce significant improvements in spatial working memory (p = 0.002 and p = 0.006 respectively), to a similar extent to that following blueberry supplementation (p = 0.002). These behavioral changes were paralleled by increases in hippocampal brain-derived neurotrophic factor (R = 0.46, p<0.01), suggesting a common mechanism for the enhancement of memory. However, unlike protein levels of BDNF, the regional enhancement of BDNF mRNA expression in the hippocampus appeared to be predominantly enhanced by anthocyanins. Our data support the claim that flavonoids are likely causal agents in mediating the cognitive effects of flavonoid-rich foods.

Dietary (poly)phenolics in human health: structures, bioavailability, and evidence of protective effects against chronic diseases

Human intervention trials have provided evidence for protective effects of various (poly)phenol-rich foods against chronic disease, including cardiovascular disease, neurodegeneration, and cancer. While there are considerable data suggesting benefits of (poly)phenol intake, conclusions regarding their preventive potential remain unresolved due to several limitations in existing studies. Bioactivity investigations using cell lines have made an extensive use of both (poly)phenolic aglycones and sugar conjugates, these being the typical forms that exist in planta, at concentrations in the low-μM-to-mM range. However, after ingestion, dietary (poly)phenolics appear in the circulatory system not as the parent compounds, but as phase II metabolites, and their presence in plasma after dietary intake rarely exceeds nM concentrations. Substantial quantities of both the parent compounds and their metabolites pass to the colon where they are degraded by the action of the local microbiota, giving rise principally to small phenolic acid and aromatic catabolites that are absorbed into the circulatory system. This comprehensive review describes the different groups of compounds that have been reported to be involved in human nutrition, their fate in the body as they pass through the gastrointestinal tract and are absorbed into the circulatory system, the evidence of their impact on human chronic diseases, and the possible mechanisms of action through which (poly)phenol metabolites and catabolites may exert these protective actions. It is concluded that better performed in vivo intervention and in vitro mechanistic studies are needed to fully understand how these molecules interact with human physiological and pathological processes.

Extra virgin olive oil (EVOO) consumption and antioxidant status in healthy institutionalized elderly humans

Recent studies show that the elderly have increased oxidative stress and impaired antioxidant defense systems. Our study aims to evaluate the effects of daily consumption of EVOO in the healthy institutionalized elderly. We studied anthropometric, biochemical and antioxidant parameters in 62 subjects aged 65-96 years after a 6-week daily intake of polyphenol-rich EVOO with high oleuropein derivative contents. Subjects were divided into a control group (CG) who maintained their dietary habits (n=39) and an olive group (OG) who consumed EVOO as the only added fat, plus a daily dose of 50ml (n=23). We found a significant reduction of total cholesterol (TC), HDL, LDL and TGs in OG subjects and a significant increase of HDL levels. There was no significant variation in the CG parameters. In OG the total antioxidant capacity (TAC) in plasma increased with significant differences over CG. Plasma hydroxytyrosol (OH-Tyr) concentration showed a significant increase after EVOO intervention. Daily consumption of EVOO was found to have positive effects on lipid profiles, OH-Tyr levels and TAC. The results also show a significant increase of catalase (CAT) in erythrocytes and a decrease (p<0.05) in superoxide dismutase (SOD) and glutathione peroxidase (GH-PX) activity after EVOO intake. To our knowledge, no other study has examined the effects of EVOO consumption on biochemical parameters, antioxidant capacity and antioxidant enzyme activity in healthy elderly subjects. In conclusion, our results show that nutritional intervention with EVOO improves antioxidant status in healthy elderly people.

Blueberry anthocyanins at doses of 0.5 and 1 % lowered plasma cholesterol by increasing fecal excretion of acidic and neutral sterols in hamsters fed a cholesterol-enriched diet

PURPOSE

The present study investigated the underlying mechanism associated with the hypocholesterolemic activity of blueberry anthocyanins by examining its effect on fecal sterol excretion and gene expression of major receptors, enzymes, and transporters involved in cholesterol metabolism.

METHODS

Hamsters were divided into three groups and fed a 0.1 % cholesterol diet containing 0 % (CTL), 0.5 % (BL), and 1.0 % (BH) blueberry anthocyanins, respectively, for six weeks. Plasma total cholesterol (TC), triacylglycerols (TAG), and non-high-density lipoproteins cholesterol (non-HDL-C) were measured using the enzymatic kits, and the gene expression of transporters, enzymes, and receptors involved in cholesterol absorption and metabolism was quantified using the quantitative PCR. GC analysis was used to quantify hepatic cholesterol and fecal acidic and neutral sterols.

RESULTS

Dietary supplementation of 0.5 and 1.0 % blueberry anthocyanins for 6 weeks decreased plasma TC concentration by 6-12 % in a dose-dependent manner. This was accompanied by increasing the excretion of fecal neutral and acidic sterols by 22-29 % and 41-74 %, respectively. Real-time PCR analyses demonstrated that incorporation of blueberry anthocyanins into diet down-regulated the genes of NPC1L1, ACAT-2, MTP, and ABCG 8. In addition, blueberry anthocyanins were also able to down-regulate the gene expression of hepatic HMG-CoA reductase.

CONCLUSION

The cholesterol-lowering activity of blueberry anthocyanins was most likely mediated by enhancing the excretion of sterols accompanied with down-regulation on gene expression of intestinal NPC1L1, ACAT-2, MTP, and ABCG 8.

Inhibition of neuroinflammation by cinnamon and its main components

Uncontrolled activation of microglia contributes to neuroinflammation, which is highly involved in the development of neurodegenerative diseases. Although cinnamon has neuro-protective properties, its capacity to inhibit neuroinflammation has not been investigated and its active compounds remain unclear. Therefore, the composition of cinnamon extract was analysed by LC-MS and the ability of cinnamon and its main constituents to inhibit neuroinflammation was evaluated using a lipopolysaccharide (LPS)-activated BV2 microglia culture system. In total, 50 μg/mL cinnamon extract decreased significantly the production and expression of nitric oxide (NO), interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in LPS-activated BV2 microglia. Blocking of nuclear factor-κB (NF-κB) activation was the most likely mechanism responsible for inhibition by cinnamon of neuroinflammation. Among the eight tested compounds, cinnamaldehyde had the greatest anti-neuroinflammatory capacity. Experimental results suggest that cinnamon may have a potential therapeutic effect against neurodegenerative diseases and its potent anti-neuroinflammatory capacity was primarily attributed to cinnamaldehyde.

Antioxidant-Enriched Diet Affects Early Microglia Accumulation and Promotes Regeneration of the Striatal Dopamine System after a 6-Hydroxidopamine-Induced Lesion in a Rat

Neuroinflammation is found both in the brain of humans suffering from Parkinson's disease and in animal models of disease. It is suggested to be involved in the pathogenesis of the disease. In the present study, in order to study the effects of antioxidants on neuroinflammation, microglial phenotypes were evaluated in rats fed with diets containing bilberries, blueberries, or crowberries at 1 and 4 weeks following striatal injection of 6-hydroxydopamine. The dopamine innervation was visualized using antibodies raised against tyrosine hydroxlase (TH) in the striatum and in the globus pallidus. One week post-lesion, the expression of Iba1-positive cells, a general microglial marker, was significantly increased in the striatum of all animals fed with antioxidant-enriched diets compared to control-diet fed animals, while the diameter of the TH-negative zone was similar in all animals. At four weeks post-lesion, the Iba1-positive microglia was significantly reduced in animals fed with antioxidant-enriched diets. The diameter of the TH-negative zone was significantly reduced in animals fed bilberry and crowberry. The expression and distribution of ED1-positive cells was similar to that of Iba1-positive cells found in the lesioned areas. A cell division marker Ki67 revealed that few microglia were proliferating in crowberry-treated animals. Otherwise dividing cells were associated with blood capillary cells. Although the antioxidant level should be equal in the entire brain, no regeneration was found in globus pallidus, suggesting the mechanism promoting regeneration in the striatum is not effective in the globus pallidus. In conclusion, diets rich in bilberries and crowberries and with high contents of antioxidants stimulate an early phase of accumulation of reactive migroglia that fades at longer time points i.e. promotes regeneration of the striatal dopamine system.

Blueberry supplementation induces spatial memory improvements and region-specific regulation of hippocampal BDNF mRNA expression in young rats

RATIONALE

Flavonoid-rich foods have been shown to be able to reverse age-related cognitive deficits in memory and learning in both animals and humans. However, to date, there have been only a limited number of studies investigating the effects of flavonoid-rich foods on cognition in young/healthy animals.

OBJECTIVES

The aim of this study was to investigate the effects of a blueberry-rich diet in young animals using a spatial working memory paradigm, the delayed non-match task, using an eight-arm radial maze. Furthermore, the mechanisms underlying such behavioural effects were investigated.

RESULTS

We show that a 7-week supplementation with a blueberry diet (2 % w/w) improves the spatial memory performance of young rats (2 months old). Blueberry-fed animals also exhibited a faster rate of learning compared to those on the control diet. These behavioural outputs were accompanied by the activation of extracellular signal-related kinase (ERK1/2), increases in total cAMP-response element-binding protein (CREB) and elevated levels of pro- and mature brain-derived neurotrophic factor (BDNF) in the hippocampus. Changes in hippocampal CREB correlated well with memory performance. Further regional analysis of BDNF gene expression in the hippocampus revealed a specific increase in BDNF mRNA in the dentate gyrus and CA1 areas of hippocampi of blueberry-fed animals.

CONCLUSIONS

The present study suggests that consumption of flavonoid-rich blueberries has a positive impact on spatial learning performance in young healthy animals, and these improvements are linked to the activation of ERK-CREB-BDNF pathway in the hippocampus.

Low-density lipoprotein receptor-related protein 1: a physiological Aβ homeostatic mechanism with multiple therapeutic opportunities

Low-density lipoprotein receptor-related protein-1 (LRP1) is the main cell surface receptor involved in brain and systemic clearance of the Alzheimer's disease (AD) toxin amyloid-beta (Aβ). In plasma, a soluble form of LRP1 (sLRP1) is the major transport protein for peripheral Aβ. LRP1 in brain endothelium and mural cells mediates Aβ efflux from brain by providing a transport mechanism for Aβ across the blood-brain barrier (BBB). sLRP1 maintains a plasma 'sink' activity for Aβ through binding of peripheral Aβ which in turn inhibits re-entry of free plasma Aβ into the brain. LRP1 in the liver mediates systemic clearance of Aβ. In AD, LRP1 expression at the BBB is reduced and Aβ binding to circulating sLRP1 is compromised by oxidation. Cell surface LRP1 and circulating sLRP1 represent druggable targets which can be therapeutically modified to restore the physiological mechanisms of brain Aβ homeostasis. In this review, we discuss how increasing LRP1 expression at the BBB and liver with lifestyle changes, statins, plant-based active principles and/or gene therapy on one hand, and how replacing dysfunctional plasma sLRP1 on the other regulate Aβ clearance from brain ultimately controlling the onset and/or progression of AD.

Nutrition, adult hippocampal neurogenesis and mental health

INTRODUCTION

Over the last 8 years, emerging studies bridging the gap between nutrition and mental health have resolutely established that learning and memory abilities as well as mood can be influenced by diet. However, the mechanisms by which diet modulates mental health are still not well understood. Sources of data In this article, a review of the literature was conducted using PubMed to identify studies that provide functional implications of adult hippocampal neurogenesis (AHN) and its modulation by diet.

AREAS OF AGREEMENT

One of the brain structures associated with learning and memory as well as mood is the hippocampus. Importantly, the hippocampus is one of the two structures in the adult brain where the formation of newborn neurons, or neurogenesis, persists.

AREAS OF CONTROVERSY

The exact roles of these newborn neurons in learning, memory formation and mood regulation remain elusive.

GROWING POINTS

Nevertheless, there has been accumulating evidence linking cognition and mood to neurogenesis occurring in the adult hippocampus. Therefore, modulation of AHN by diet emerges as a possible mechanism by which nutrition impacts on mental health.

AREAS TIMELY FOR DEVELOPING RESEARCH

This area of investigation is new and needs attention because a better understanding of the neurological mechanisms by which nutrition affect mental health may lead to novel dietary approaches for disease prevention, healthier ageing and discovery of new therapeutic targets for mental illnesses.

Consumption of blueberries with a high-carbohydrate, low-fat breakfast decreases postprandial serum markers of oxidation

We sought to determine whether consumption of blueberries could reduce postprandial oxidation when consumed with a typical high-carbohydrate, low-fat breakfast. Participants (n 14) received each of the three treatments over 3 weeks in a cross-over design. Treatments consisted of a high blueberry dose (75 g), a low blueberry dose (35 g) and a control (ascorbic acid and sugar content matching that of the high blueberry dose). Serum oxygen radical absorbance capacity (ORAC), serum lipoprotein oxidation (LO) and serum ascorbate, urate and glucose were measured at fasting, and at 1, 2 and 3 h after sample consumption. The mean serum ORAC was significantly higher in the 75 g group than in the control group during the first 2 h postprandially, while serum LO lag time showed a significant trend over the 3 h for both blueberry doses. Changes in serum ascorbate, urate and glucose were not significantly different among the groups. To our knowledge, this is the first report that has demonstrated that increased serum antioxidant capacity is not attributable to the fructose or ascorbate content of blueberries. In summary, a practically consumable quantity of blueberries (75 g) can provide statistically significant oxidative protection in vivo after a high-carbohydrate, low-fat breakfast. Though not tested directly, it is likely that the effects are due to phenolic compounds, either directly or indirectly, as they are a major family of compounds in blueberries with potential bioactive activity.

Blueberries and neuronal aging

As the population of people in the United States over the age of 65 years continues to increase, so too will the incidence of age-related pathologies, including decreases in cognitive and motor function. In cases of severe deficits in memory or motor function, hospitalization and/or custodial care would be a likely outcome. This means that unless some way is found to reduce these age-related decrements in neuronal function, health care costs will continue to rise exponentially. Evidence is accumulating that consumption of blueberries may be one strategy to forestall or even reverse age-related neuronal deficits, as well as their subsequent behavioral manifestations, in order to increase healthy aging. Research suggests that the polyphenolic compounds found in blueberries exert their beneficial effects either through their ability to lower oxidative stress and inflammation or directly by altering the signaling involved in neuronal communication. These interventions, in turn, may protect against age-related deficits in cognitive and motor function. Appropriately, the US Department of Agriculture has figured prominently in these discoveries, through the efforts of two USDA researchers who worked for the department 100 years apart.

Effect of dietary blueberry pomace on selected metabolic factors associated with high fructose feeding in growing Sprague-Dawley rats

An experiment was conducted to study the protective effect of feeding extruded and unextruded blueberry pomace (BBP) on selected metabolic parameters associated with metabolic syndrome in a model of high fructose (HF)-fed growing Sprague-Dawley rats. Treatments were as follows: (1) control (modified AIN-based diet); (2) HF diet (AIN diet with 58% fructose); (3) HF diet with 1.5% unextruded BBP; (4) HF diet with 1.5% extruded BBP; (5) HF diet with 3% unextruded BBP; and (6) HF diet with 3% extruded BBP. Compared with the control, HF feeding increased fasting plasma insulin and fasting and postprandial plasma triglycerides as well as homeostatic scores of insulin resistance and β-cell function, but not weight gain, diet intake and efficiency, abdominal fat, oral glucose tolerance, and fasting and postprandial plasma glucose, cholesterol, and leptin levels. Inclusion of unextruded or extruded BBP was effective in minimizing or ameliorating the fructose-induced metabolic anomalies, except postprandial plasma triglycerides, especially at 3% of the diet. In addition, unextruded or extruded BBP at 3% of the diet was also able to reduce plasma cholesterol and abdominal fat relative to the HF control, which may impart additional health benefits. Compared with the control, inclusion of unextruded or extruded BBP at both 1.5% and 3% resulted in lower total fat weight, and animals fed a diet supplemented with 3% unextruded BBP in fasting state or 3% unextruded BBP in fed state had lower leptin levels than the control. This is the first study demonstrating the beneficial effects of feeding blueberry pomace on health.

Prophylactic neuroprotection by blueberry-enriched diet in a rat model of light-induced retinopathy

The role of anthocyanins is controversial in vision health. This study investigates the impact of a blueberry-enriched diet as neuroprotectant in a rat model of light-induced retinopathy. Thirty-eight albino Wistar rats and 25 pigmented Brown-Norway rats were fed by gavage with long (7 weeks) and short (2 weeks) intervention with fortified blueberry juice (1 ml; 2.8 mg cyanidin 3-glucoside equivalents) or with a placebo solution (7 weeks) that contained the abundant nonanthocyanin blueberry phenolic, namely, chlorogenic acid, before being submitted to 2 hours of intense light regimen (1.8×10(4) lux). Retinal health was measured by fitting electroretinogram responses with the Naka-Rushton equation. The light-induced retinal damage was severe in the placebo groups, with the maximum amplitude of the electroretinogram being significantly reduced in both Wistar and Brown-Norway rats. The maximum amplitude of the electroretinogram was significantly protected from the light insult in the Wistar rats supplemented with blueberry juice for 7 or 2 weeks, and there was no significant difference between these two groups. The same dietary intervention in the Brown-Norway groups failed to protect the retina. Histological examination of retinal section confirmed the electroretinography results, showing protection of the outer nuclear layer of the retina in the Wistar rats fed with blueberries, while all placebo-fed rats and blueberry-fed Brown-Norway rats showed evidence of retinal damage concentrated in the superior hemiretina. The neuroprotective potential of anthocyanins in this particular model is discussed in terms of interaction with rhodopsin/phototransduction and in terms of antioxidative capacity.