Chronic Consumption of Cranberries (Vaccinium macrocarpon) for 12 Weeks Improves Episodic Memory and Regional Brain Perfusion in Healthy Older Adults: A Randomised, Placebo-Controlled, Parallel-Groups Feasibility Study

Effects of Anthocyanins on Cognition and Vascular Function: A Systematic Review

SCOPE

Good vascular function is crucial for cerebral blood flow and cognitive performance. Diets high in anthocyanins have been shown to improve vascular function and are associated with improvements in cognition. This systematic review investigates randomized controlled trials examining the impact of anthocyanin intake on both cognition and vascular function.

METHODS AND RESULTS

Of the 1486 studies identified through searching Ovid Medline and AMED, PsychInfo, Web of Science, and Scopus, 20 studies are selected which measured cognitive and vascular function. Overall, positive effects on verbal and working memory are observed, which are supported by studies using functional magnetic resonance imaging to demonstrate increased blood flow in brain regions related to these cognitive domains. However, effects of anthocyanins on blood pressure and markers of endothelial function are inconsistent.

CONCLUSION

This systematic review provides evidence for a positive effect of anthocyanins on cognition and insight into the relevance of endothelial function. Anthocyanins are widely available and can be easily consumed in a range of different fruits, vegetables, and other products. Further studies should establish the optimal daily intake of anthocyanins for cardiovascular and cognitive health.

The Effects of Cranberry Consumption on Glycemic and Lipid Profiles in Humans: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

This study aims to update the evidence and clarify whether cranberry possesses lipid-lowering and hypoglycemic properties in humans. PubMed, Web of Science, and Scopus were searched to identify relevant articles published up to December 2023. In total, 3145 publications were reviewed and 16 of them were included for qualitative synthesis and meta-analysis. Stata 15.0 and Review Manager 5.4 were applied for statistical analyses. The results revealed a significant decrease in the total cholesterol to high-density lipoprotein cholesterol ratio (TC/HDL-C) (MD = -0.24; 95% CI: -0.45, -0.04; peffect = 0.02) and homeostasis model assessment of insulin resistance (HOMA-IR) (MD = -0.59; 95% CI: -1.05, -0.14; peffect = 0.01) with cranberry consumption. However, it did not influence total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), fasting blood glucose (FBG), glycated hemoglobin (HbA1c), and fasting insulin. In subgroup analysis, cranberry consumption in dried form (capsules, powder, and tablets) was found to significantly decrease the fasting insulin level (three studies, one hundred sixty-five participants, MD = -2.16; 95% CI: -4.24, -0.07; peffect = 0.04), while intervention duration, health conditions, and dosage of polyphenols and anthocyanins had no impact on blood lipid and glycemic parameters. In summary, cranberry might have potential benefits in regulating lipid and glucose profiles.

Short term supplementation with cranberry extract modulates gut microbiota in human and displays a bifidogenic effect

Cranberry is associated with multiple health benefits, which are mostly attributed to its high content of (poly)phenols, particularly flavan-3-ols. However, clinical trials attempting to demonstrate these positive effects have yielded heterogeneous results, partly due to the high inter-individual variability associated with gut microbiota interaction with these molecules. In fact, several studies have demonstrated the ability of these molecules to modulate the gut microbiota in animal and in vitro models, but there is a scarcity of information in human subjects. In addition, it has been recently reported that cranberry also contains high concentrations of oligosaccharides, which could contribute to its bioactivity. Hence, the aim of this study was to fully characterize the (poly)phenolic and oligosaccharidic contents of a commercially available cranberry extract and evaluate its capacity to positively modulate the gut microbiota of 28 human subjects. After only four days, the (poly)phenols and oligosaccharides-rich cranberry extract, induced a strong bifidogenic effect, along with an increase in the abundance of several butyrate-producing bacteria, such as Clostridium and Anaerobutyricum. Plasmatic and fecal short-chain fatty acids profiles were also altered by the cranberry extract with a decrease in acetate ratio and an increase in butyrate ratio. Finally, to characterize the inter-individual variability, we stratified the participants according to the alterations observed in the fecal microbiota following supplementation. Interestingly, individuals having a microbiota characterized by the presence of Prevotella benefited from an increase in Faecalibacterium with the cranberry extract supplementation.

Unravelling phenolic metabotypes in the frame of the COMBAT study, a randomized, controlled trial with cranberry supplementation

Cranberry (poly)phenols may have potential health benefits. Circulating (poly)phenol metabolites can act as mediators of these effects, but they are subjected to an extensive inter-individual variability. This study aimed to quantify both plasma and urine (poly)phenol metabolites following a 12-week intake of a cranberry powder in healthy older adults, and to investigate inter-individual differences by considering the existence of urinary metabotypes related to dietary (poly)phenols. Up to 13 and 67 metabolites were quantified in plasma and urine respectively. Cranberry consumption led to changes in plasma metabolites, mainly hydroxycinnamates and hippuric acid. Individual variability in urinary metabolites was assessed using different data sets and a combination of statistical models. Three phenolic metabotypes were identified, colonic metabolism being the main driver for subject clustering. Metabotypes were characterized by quali-quantitative differences in the excretion of some metabolites such as phenyl-γ-valerolactones, hydroxycinnamic acids, and phenylpropanoic acids. Metabotypes were further confirmed when applying a model only focused on flavan-3-ol colonic metabolites. 5-(3',4'-dihydroxyphenyl)-γ-valerolactone derivatives were the most relevant metabolites for metabotyping. Metabotype allocation was well preserved after 12-week intervention. This metabotyping approach for cranberry metabolites represents an innovative step to handle the complexity of (poly)phenol metabolism in free-living conditions, deciphering the existence of metabotypes derived from the simultaneous consumption of different classes of (poly)phenols. These results will help contribute to studying the health effects of cranberries and other (poly)phenol-rich foods, mainly considering gut microbiota-driven individual differences.

Role of fruit and vegetables in sustaining healthy cognitive function: evidence and issues

Modifiable lifestyle factors, such as improved nutrition, are crucial in maintaining cognitive health in older age. Fruit and vegetables represent healthy and sustainable sources of nutrients with the potential to prevent age-related cognitive decline. The aim of this review is to synthesise the available evidence, from epidemiological and randomised controlled trials (RCT), regarding the role of fruit and vegetables in sustaining healthy cognitive function. Epidemiological studies of combined fruit and vegetable intake suggest that increased consumption may sustain cognition in later life. The evidence appears to be stronger for an association between vegetables and cognition, particularly for green leafy and cruciferous vegetables. Specific benefits shown for berries, citrus fruits, avocado and nuts suggest fruit is worthy of further investigation in relation to cognition. Data from RCT indicate benefits to differing aspects of cognition following citrus and berry fruits, cocoa and peanuts, but the data are limited and there are a lack of studies exploring effects of vegetables. There is growing evidence for an association between fruit and vegetable intake and cognitive function, but this is not always consistent and the data from RCT are limited. Issues in previous research are highlighted, such as strict exclusion criteria, absence of baseline nutritional status data and lack of consideration of individual differences, which may explain the weaker findings from RCT. Inclusion of those most at risk for cognitive decline is recommended in future nutrition and cognition research.

Gastrointestinal Dysfunction in Neurological and Neurodegenerative Disorders

Increasing research links the gut microbiome to neurodegenerative disorders. The gut microbiome communicates with the central nervous system via the gut-brain axis and affects behavioral and cognitive phenotypes. Dysbiosis (a dysfunctional microbiome) drives increased intestinal permeability and inflammation that can negatively affect the brain via the gut-brain axis. Healthier metabolic and lipid profiles and cognitive phenotypes are observed in individuals with more distinct microbiomes. In this review, we discuss the role of the gut microbiome and gut-brain axis in neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease and related animal models, in cancer and cancer treatments, and in metabolic syndrome. We also discuss strategies to improve the gut microbiome and ultimately brain function. Because healthier cognitive phenotypes are observed in individuals with more distinct microbiomes, increased efforts are warranted to develop therapeutic strategies for those at increased risk of developing neurological disorders and patients diagnosed with those disorders.

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.

Neuroprotective Effects of Agri-Food By-Products Rich in Phenolic Compounds

Neurodegenerative diseases are known for their wide range of harmful conditions related to progressive cell damage, nervous system connections and neuronal death. These pathologies promote the loss of essential motor and cognitive functions, such as mobility, learning and sensation. Neurodegeneration affects millions of people worldwide, and no integral cure has been created yet. Here, bioactive compounds have been proven to exert numerous beneficial effects due to their remarkable bioactivity, so they could be considered as great options for the development of new neuroprotective strategies. Phenolic bioactives have been reported to be found in edible part of plants; however, over the last years, a large amount of research has focused on the phenolic richness that plant by-products possess, which sometimes even exceeds the content in the pulp. Thus, their possible application as an emergent neuroprotective technique could also be considered as an optimal strategy to revalorize these agricultural residues (those originated from plant processing). This review aims to summarize main triggers of neurodegeneration, revise the state of the art in plant extracts and their role in avoiding neurodegeneration and discuss how their main phenolic compounds could exert their neuroprotective effects. For this purpose, a diverse search of studies has been conducted, gathering a large number of papers where by-products were used as strong sources of phenolic compounds for their neuroprotective properties. Finally, although a lack of investigation is quite remarkable and greatly limits the use of these compounds, phenolics remain attractive for research into new multifactorial anti-neurodegenerative nutraceuticals.

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.