Addressing the inter-individual variation in response to consumption of plant food bioactives: Towards a better understanding of their role in healthy aging and cardiometabolic risk reduction

Cardiometabolic benefits of a non-industrialized-type diet are linked to gut microbiome modulation

Industrialization adversely affects the gut microbiome and predisposes individuals to chronic non-communicable diseases. We tested a microbiome restoration strategy comprising a diet that recapitulated key characteristics of non-industrialized dietary patterns (restore diet) and a bacterium rarely found in industrialized microbiomes (Limosilactobacillus reuteri) in a randomized controlled feeding trial in healthy Canadian adults. The restore diet, despite reducing gut microbiome diversity, enhanced the persistence of L. reuteri strain from rural Papua New Guinea (PB-W1) and redressed several microbiome features altered by industrialization. The diet also beneficially altered microbiota-derived plasma metabolites implicated in the etiology of chronic non-communicable diseases. Considerable cardiometabolic benefits were observed independently of L. reuteri administration, several of which could be accurately predicted by baseline and diet-responsive microbiome features. The findings suggest that a dietary intervention targeted toward restoring the gut microbiome can improve host-microbiome interactions that likely underpin chronic pathologies, which can guide dietary recommendations and the development of therapeutic and nutritional strategies.

Individual Responses to Repeated Dosing with Anthocyanin-Rich New Zealand Blackcurrant Extract During High-Intensity Intermittent Treadmill Running in Active Males

Intake of New Zealand blackcurrant (NZBC) extract for 7 days has been shown to improve high-intensity intermittent running (HIIR) performance.

OBJECTIVES

We examined the repeat response of NZBC extract on HIIR performance.

METHODS

Sixteen active males (age: 23 ± 3 yrs, height: 179 ± 5 cm, mass: 79 ± 11 kg, V˙O2max: 55.3 ± 5 mL∙kg-1∙min-1, velocity at V˙O2max: 17.2 ± 0.8 km∙h-1, mean ± SD) participated. Familiarized subjects completed the HIIR test at individualized exercise intensities with stages consisting of six 19 s high-intensity running bouts interspersed by 15 s of low-intensity running and 1 min of inter-stage rest. The test was repeated at increasing speeds until exhaustion, under four conditions; two with a daily dose of 600 mg of NZBC extract (CurraNZ™, providing 210 mg anthocyanins) and two with a placebo, each over 7 days. The study used a double-blind, randomized, cross-over design with a wash-out period of at least 14 days.

RESULTS

For the cohort, there were no differences between the placebo and NZBC conditions for mean heart rate (p = 0.071), mean oxygen uptake (p = 0.713), and mean lactate (p = 0.121) at exhaustion for the HIIR. The NZBC extract increased the mean total running distance and mean high-intensity running distance by 7.9% and 8.0% compared to the placebo. With NZBC extract, 8 of the 16 participants (50%) enhanced in both trials beyond the smallest worthwhile change for total running distance (≥173 m) and high-intensity running distance (≥111 m). For repeated responders, total running distance and high-intensity running distance was increased by 16.7% (95% CI [11.0, 22.4%] and 16.6% (95% CI [11.0, 22.2%]. Three participants had enhanced running performance in one trial beyond the SWC, and five participants were considered non-responders.

CONCLUSIONS

This is the first study on the repeated response by an anthocyanin-rich supplement on high-intensity running performance. New Zealand blackcurrant extract can substantially enhance intermittent high-intensity running performance in consistent responders. Future work should examine dosing strategies of New Zealand blackcurrant, and whether a repeated response rate exceeding 50% can be attained. These findings suggest that NZBC extract could be beneficial for athletes participating in high-intensity team sports.

Correlation between vitamin D metabolic pathway-related gene polymorphisms and cardiovascular disease

Vitamin D plays important roles in various physiological processes such as cardiovascular health, calcium balance regulation, bone health, immune system support, neurological function regulation, muscle function maintenance, and anti-inflammatory effects. Therefore, maintaining its adequate levels is essential for overall health. Genetic polymorphisms in vitamin D metabolic pathways have become a key factor affecting the susceptibility and progression of cardiovascular disease (CVD). This article reviews the relationship between gene polymorphisms in vitamin D metabolic pathways and vitamin D levels or CVD. It is emphasized that the polymorphisms of key genes such as GC, VDR, CYP2R1, CYP24A1 and CYP27B1 are related to the pathogenesis of CVD. These polymorphisms can regulate serum levels of vitamin D, thereby affecting the susceptibility, comorbidities and clinical manifestations of CVD. Despite the progress made, there are still inconsistencies and gaps in the literature. Thus, it is necessary to conduct large-scale, multicenter studies to verify these findings and deepen our understanding of the intricate interactions between gene polymorphisms in vitamin D metabolic pathways and CVD.

Metatranscriptomics-guided discovery and characterization of a polyphenol-metabolizing gut microbial enzyme

Gut microbial catechol dehydroxylases are a largely uncharacterized family of metalloenzymes that potentially impact human health by metabolizing dietary polyphenols. Here, we use metatranscriptomics (MTX) to identify highly transcribed catechol-dehydroxylase-encoding genes in human gut microbiomes. We discover a prevalent, previously uncharacterized catechol dehydroxylase (Gp Hcdh) from Gordonibacter pamelaeae that dehydroxylates hydrocaffeic acid (HCA), an anti-inflammatory gut microbial metabolite derived from plant-based foods. Further analyses suggest that the activity of Gp Hcdh may reduce anti-inflammatory benefits of polyphenol-rich foods. Together, these results show the utility of combining MTX analysis and biochemical characterization for gut microbial enzyme discovery and reveal a potential link between host inflammation and a specific polyphenol-metabolizing gut microbial enzyme.

Dietary (poly)phenols as modulators of the biophysical properties in endothelial cell membranes: its impact on nitric oxide bioavailability in hypertension

Hypertension is a major contributor to premature death, owing to the associated increased risk of damage to the heart, brain and kidneys. Although hypertension is manageable by medication and lifestyle changes, the risk increases with age. In an increasingly aged society, the incidence of hypertension is escalating, and is expected to increase the prevalence of (cerebro)vascular events and their associated mortality. Adherence to plant-based diets improves blood pressure and vascular markers in individuals with hypertension. Food flavonoids have an inhibitory effect towards angiotensin-converting enzyme (ACE1) and although this effect is greatly diminished upon metabolization, their microbial metabolites have been found to improve endothelial nitric oxide synthase (eNOS) activity. Considering the transmembrane location of ACE1 and eNOS, the ability of (poly)phenols to interact with membrane lipids modulate the cell membrane's biophysical properties and impact on nitric oxide (·NO) synthesis and bioavailability, remain poorly studied. Herein, we provide an overview of the current knowledge on the lipid remodeling of endothelial membranes with age, its impact on the cell membrane's biophysical properties and ·NO permeability across the endothelial barrier. We also discuss the potential of (poly)phenols and other plant-based compounds as key players in hypertension management, and address the caveats and challenges in adopted methodologies.

Flavan-3-ols and Vascular Health: Clinical Evidence and Mechanisms of Action

Cardiovascular diseases (CVDs) are one of the main causes of mortality and morbidity worldwide. A healthy diet rich in plant-derived compounds such as (poly)phenols appears to have a key role in improving cardiovascular health. Flavan-3-ols represent a subclass of (poly)phenols of great interest for their possible health benefits. In this review, we summarized the results of clinical studies on vascular outcomes of flavan-3-ol supplementation and we focused on the role of the microbiota in CVD. Clinical trials included in this review showed that supplementation with flavan-3-ols mostly derived from cocoa products significantly reduces blood pressure and improves endothelial function. Studies on catechins from green tea demonstrated better results when involving healthy individuals. From a mechanistic point of view, emerging evidence suggests that microbial metabolites may play a role in the observed effects. Their function extends beyond the previous belief of ROS scavenging activity and encompasses a direct impact on gene expression and protein function. Although flavan-3-ols appear to have effects on cardiovascular health, further studies are needed to clarify and confirm these potential benefits and the rising evidence of the potential involvement of the microbiota.

Biomarkers of food intake and their relevance to metabolic syndrome

Metabolic syndrome (MetS) constitutes a prevalent risk factor associated with non communicable diseases such as cardiovascular disease and type 2 diabetes. A major factor impacting the etiology of MetS is diet. Dietary patterns and several individual food constituents have been related to the risk of developing MetS or have been proposed as adjuvant treatment. However, traditional methods of dietary assessment such as 24 h recalls rely greatly on intensive user-interaction and are subject to bias. Hence, more objective methods are required for unbiased dietary assessment and efficient prevention. While it is accepted that some dietary-derived constituents in blood plasma are indicators for certain dietary patterns, these may be too unstable (such as vitamin C as a marker for fruits/vegetables) or too broad (e.g. polyphenols for plant-based diets) or reflect too short-term intake only to allow for strong associations with prolonged intake of individual food groups. In the present manuscript, commonly employed biomarkers of intake including those related to specific food items (e.g. genistein for soybean or astaxanthin and EPA for fish intake) and novel emerging ones (e.g. stable isotopes for meat intake or microRNA for plant foods) are emphasized and their suitability as biomarker for food intake discussed. Promising alternatives to plasma measures (e.g. ethyl glucuronide in hair for ethanol intake) are also emphasized. As many biomarkers (i.e. secondary plant metabolites) are not limited to dietary assessment but are also capable of regulating e.g. anti-inflammatory and antioxidant pathways, special attention will be given to biomarkers presenting a double function to assess both dietary patterns and MetS risk.

Phytonutrients in the promotion of healthspan: a new perspective

Considering a growing, aging population, the need for interventions to improve the healthspan in aging are tantamount. Diet and nutrition are important determinants of the aging trajectory. Plant-based diets that provide bioactive phytonutrients may contribute to offsetting hallmarks of aging and reducing the risk of chronic disease. Researchers now advocate moving toward a positive model of aging which focuses on the preservation of functional abilities, rather than an emphasis on the absence of disease. This narrative review discusses the modulatory effect of nutrition on aging, with an emphasis on promising phytonutrients, and their potential to influence cellular, organ and functional parameters in aging. The literature is discussed against the backdrop of a recent conceptual framework which describes vitality, intrinsic capacity and expressed capacities in aging. This aims to better elucidate the role of phytonutrients on vitality and intrinsic capacity in aging adults. Such a review contributes to this new scientific perspective-namely-how nutrition might help to preserve functional abilities in aging, rather than purely offsetting the risk of chronic disease.

Tapping into Nature's Arsenal: Harnessing the Potential of Natural Antioxidants for Human Health and Disease Prevention

Numerous natural antioxidants commonly found in our daily diet have demonstrated significant benefits for human health and various diseases by counteracting the impact of reactive oxygen and nitrogen species. Their chemical properties enable a range of biological actions, including antihypertensive, antimicrobial, anti-inflammatory, anti-fibrotic, and anticancer effects. Despite promising outcomes from preclinical studies, ongoing debate persists regarding their reproducibility in human clinical models. This controversy largely stems from a lack of understanding of the pharmacokinetic properties of these compounds, coupled with the predominant focus on monotherapies in research, neglecting potential synergistic effects arising from combining different antioxidants. This study aims to provide an updated overview of natural antioxidants, operating under the hypothesis that a multitherapeutic approach surpasses monotherapy in efficacy. Additionally, this study underscores the importance of integrating these antioxidants into the daily diet, as they have the potential to prevent the onset and progression of various diseases. To reinforce this perspective, clinical findings pertaining to the treatment and prevention of non-alcoholic fatty liver disease and conditions associated with ischemia and reperfusion phenomena, including myocardial infarction, postoperative atrial fibrillation, and stroke, are presented as key references.

Demultiplexing of single-cell RNA-sequencing data using interindividual variation in gene expression

Motivation

Pooled designs for single-cell RNA sequencing, where many cells from distinct samples are processed jointly, offer increased throughput and reduced batch variation. This study describes expression-aware demultiplexing (EAD), a computational method that employs differential co-expression patterns between individuals to demultiplex pooled samples without any extra experimental steps.

Results

We use synthetic sample pools and show that the top interindividual differentially co-expressed genes provide a distinct cluster of cells per individual, significantly enriching the regulation of metabolism. Our application of EAD to samples of six isogenic inbred mice demonstrated that controlling genetic and environmental effects can solve interindividual variations related to metabolic pathways. We utilized 30 samples from both sepsis and healthy individuals in six batches to assess the performance of classification approaches. The results indicate that combining genetic and EAD results can enhance the accuracy of assignments (Min. 0.94, Mean 0.98, Max. 1). The results were enhanced by an average of 1.4% when EAD and barcoding techniques were combined (Min. 1.25%, Median 1.33%, Max. 1.74%). Furthermore, we demonstrate that interindividual differential co-expression analysis within the same cell type can be used to identify cells from the same donor in different activation states. By analysing single-nuclei transcriptome profiles from the brain, we demonstrate that our method can be applied to nonimmune cells.

Availability and implementation

EAD workflow is available at https://isarnassiri.github.io/scDIV/ as an R package called scDIV (acronym for single-cell RNA-sequencing data demultiplexing using interindividual variations).

Factors driving the inter-individual variability in the metabolism and bioavailability of (poly)phenolic metabolites: A systematic review of human studies

This systematic review provides an overview of the available evidence on the inter-individual variability (IIV) in the absorption, distribution, metabolism, and excretion (ADME) of phenolic metabolites and its determinants. Human studies were included investigating the metabolism and bioavailability of (poly)phenols and reporting IIV. One hundred fifty-three studies met the inclusion criteria. Inter-individual differences were mainly related to gut microbiota composition and activity but also to genetic polymorphisms, age, sex, ethnicity, BMI, (patho)physiological status, and physical activity, depending on the (poly)phenol sub-class considered. Most of the IIV has been poorly characterised. Two major types of IIV were observed. One resulted in metabolite gradients that can be further classified into high and low excretors, as seen for all flavonoids, phenolic acids, prenylflavonoids, alkylresorcinols, and hydroxytyrosol. The other type of IIV is based on clusters of individuals defined by qualitative differences (producers vs. non-producers), as for ellagitannins (urolithins), isoflavones (equol and O-DMA), resveratrol (lunularin), and preliminarily for avenanthramides (dihydro-avenanthramides), or by quali-quantitative metabotypes characterized by different proportions of specific metabolites, as for flavan-3-ols, flavanones, and even isoflavones. Future works are needed to shed light on current open issues limiting our understanding of this phenomenon that likely conditions the health effects of dietary (poly)phenols.

Interindividual differences in aronia juice tolerability linked to gut microbiome and metabolome changes-secondary analysis of a randomized placebo-controlled parallel intervention trial

BACKGROUND

Aronia melanocarpa is a berry rich in polyphenols known for health benefits. However, the bioavailability of polyphenols has been questioned, and the individual taste acceptance of the fruit with its specific flavor varies. We recently observed substantial differences in the tolerability of aronia juice among healthy females, with half of the individuals tolerating aronia juice without complaints. Given the importance of the gut microbiome in food digestion, we investigated in this secondary analysis of the randomized placebo-controlled parallel intervention study (ClinicalTrials.gov registration: NCT05432362) if aronia juice tolerability was associated with changes in intestinal microbiota and bacterial metabolites, seeking for potential mechanistic insights into the impact on aronia polyphenol tolerance and metabolic outcomes.

RESULTS

Forty females were enrolled for this 6-week trial, receiving either 100 ml natural aronia juice (verum, V) twice daily or a polyphenol-free placebo (P) with a similar nutritional profile, followed by a 6-week washout. Within V, individuals were categorized into those who tolerated the juice well (Vt) or reported complaints (Vc). The gut microbiome diversity, as analyzed by 16S rRNA gene-based next-generation sequencing, remained unaltered in Vc but changed significantly in Vt. A MICOM-based flux balance analysis revealed pronounced differences in the 40 most predictive metabolites post-intervention. In Vc carbon-dioxide, ammonium and nine O-glycans were predicted due to a shift in microbial composition, while in Vt six bile acids were the most likely microbiota-derived metabolites. NMR metabolomics of plasma confirmed increased lipoprotein subclasses (LDL, VLDL) post-intervention, reverting after wash out. Stool samples maintained a stable metabolic profile.

CONCLUSION

In linking aronia polyphenol tolerance to gut microbiota-derived metabolites, our study explores adaptive processes affecting lipoprotein profiles during high polyphenol ingestion in Vt and examines effects on mucosal gut health in response to intolerance to high polyphenol intake in Vc. Our results underpin the importance of individualized hormetic dosing for beneficial polyphenol effects, demonstrate dynamic gut microbiome responses to aronia juice, and emphasize personalized responses in polyphenol interventions.

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.

A 14-Day Double-Blind, Randomized, Controlled Crossover Intervention Study with Anti-Bacterial Benzyl Isothiocyanate from Nasturtium (Tropaeolum majus) on Human Gut Microbiome and Host Defense

Despite substantial heterogeneity of studies, there is evidence that antibiotics commonly used in primary care influence the composition of the gastrointestinal microbiota in terms of changing their composition and/or diversity. Benzyl isothiocyanate (BITC) from the food and medicinal plant nasturtium (Tropaeolum majus) is known for its antimicrobial activity and is used for the treatment of infections of the draining urinary tract and upper respiratory tract. Against this background, we raised the question of whether a 14 d nasturtium intervention (3 g daily, N = 30 healthy females) could also impact the normal gut microbiota composition. Spot urinary BITC excretion highly correlated with a weak but significant antibacterial effect against Escherichia coli. A significant increase in human beta defensin 1 as a parameter for host defense was seen in urine and exhaled breath condensate (EBC) upon verum intervention. Pre-to-post analysis revealed that mean gut microbiome composition did not significantly differ between groups, nor did the circulating serum metabolome. On an individual level, some large changes were observed between sampling points, however. Explorative Spearman rank correlation analysis in subgroups revealed associations between gut microbiota and the circulating metabolome, as well as between changes in blood markers and bacterial gut species.

Assessment of human inter-individual variability of phloretin metabolites in urine after apple consumption. AppleCOR study

Purpose: This study aimed to assess the inter-individual variation in phloretin absorption and metabolism and to seek possible phloretin metabotypes following apple snack consumption. Methods: The excreted phloretin metabolites in 24 h urine samples were determined by UPLC-MS/MS in 62 volunteers after acute and sustained (6 weeks) interventions in a randomized and parallel study with a daily supplementation of 80 g of a low-phloretin (39.5 μmol) or a high-phloretin (103 μmol) freeze-dried apple snacks. Results: absorption estimated as phloridzin equivalents for 62 volunteers varied almost 70-fold ranging from 0.1% to 6.94% of phloretin glycoside intake. Volunteers were stratified into low, medium and high producers and by the balance between glucuronidation and sulphation. For 74% of the volunteers phloretin-O-glucuronide was the dominant urinary metabolite, especially at the higher phloretin glycoside intake and for higher producers. Sulphate conjugation assumed greater significance for the remaining volunteers especially for low producers. Females dominated glucuronide profile (64.1%) and males dominated the low excretion group. Analysis of plasma glucose and insulin at the start and end of the sustained study showed a trend towards modest reductions for high producers. Furthermore, plausible factors contributing to the inter-individual variation in phloretin uptake are discussed. Conclusions: extensive inter-individual variability exists in the excretion of phloretin phase-II conjugates following consumption of apple snacks, which could be related to oral microbiota phloridzin-hydrolysing activity, lactase non-persistence trait or the metabotype to which the subject belongs. There were inconsistent effects on post-prandial serum glucose concentrations but there was a tendency for decreases to be associated with higher excretion of phloretin phase-II conjugates. Trial registration: The acute and sustained studies were registered at ClinicalTrials.gov Identifier: NCT03795324.

Emerging trends and applications of metabolomics in food science and nutrition

The study of all chemical processes involving metabolites is known as metabolomics. It has been developed into an essential tool in several disciplines, such as the study of plant physiology, drug development, human diseases, and nutrition. The field of food science, diagnostic biomarker research, etiological analysis in the field of medical therapy, and raw material quality, processing, and safety have all benefited from the use of metabolomics recently. Food metabolomics includes the use of metabolomics in food production, processing, and human diets. As a result of changing consumer habits and the rising of food industries all over the world, there is a remarkable increase in interest in food quality and safety. It requires the employment of various technologies for the food supply chain, processing of food, and even plant breeding. This can be achieved by understanding the metabolome of food, including its biochemistry and composition. Additionally, Food metabolomics can be used to determine the similarities and differences across crop kinds, as an indicator for tracking the process of ripening to increase crops' shelf life and attractiveness, and identifying metabolites linked to pathways responsible for postharvest disorders. Moreover, nutritional metabolomics is used to investigate the connection between diet and human health through detection of certain biomarkers. This review assessed and compiled literature on food metabolomics research with an emphasis on metabolite extraction, detection, and data processing as well as its applications to the study of food nutrition, food-based illness, and phytochemical analysis. Several studies have been published on the applications of metabolomics in food but further research concerning the use of standard reproducible procedures must be done. The results published showed promising uses in the food industry in many areas such as food production, processing, and human diets. Finally, metabolome-wide association studies (MWASs) could also be a useful predictor to detect the connection between certain diseases and low molecular weight biomarkers.

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.

Anthocyanin Effects on Vascular and Endothelial Health: Evidence from Clinical Trials and Role of Gut Microbiota Metabolites

Hypertension and derived cardiovascular disease (CVD) are among the leading causes of death worldwide. Increased oxidative stress and inflammatory state are involved in different alterations in endothelial functions that contribute to the onset of CVD. Polyphenols, and in particular anthocyanins, have aroused great interest for their antioxidant effects and their cardioprotective role. However, anthocyanins are rarely detected in blood serum because they are primarily metabolized by the gut microbiota. This review presents studies published to date that report the main results from clinical studies on the cardioprotective effects of anthocyanins and the role of the gut microbiota in the metabolism and bioavailability of anthocyanins and their influence on the composition of the microbiota. Even if it seems that anthocyanins have a significant effect on vascular health, more studies are required to better clarify which molecules and doses show vascular benefits without forgetting the crucial role of the microbiota.

Role of metabolomics in the delivery of precision nutrition

Precision nutrition aims to deliver personalised dietary advice to individuals based on their personal genetics, metabolism and dietary/environmental exposures. Recent advances have demonstrated promise for the use of omic technologies for furthering the field of precision nutrition. Metabolomics in particular is highly attractive as measurement of metabolites can capture information on food intake, levels of bioactive compounds and the impact of diets on endogenous metabolism. These aspects contain useful information for precision nutrition. Furthermore using metabolomic profiles to identify subgroups or metabotypes is attractive for the delivery of personalised dietary advice. Combining metabolomic derived metabolites with other parameters in prediction models is also an exciting avenue for understanding and predicting response to dietary interventions. Examples include but not limited to role of one carbon metabolism and associated co-factors in blood pressure response. Overall, while evidence exists for potential in this field there are also many unanswered questions. Addressing these and clearly demonstrating that precision nutrition approaches enable adherence to healthier diets and improvements in health will be key in the near future.

A monocentric, randomized, double-blind, controlled crossover trial of nasturtium (Tropaeolum majus) on the lipid regulator prostaglandin E2

Scope

As prostaglandin E2 (PGE2) has important roles in physiological and inflammatory functions, a double-blind randomized controlled crossover study to investigate the potential of nasturtium (Tropaeolum majus) for modulating PGE2 was conducted, aiming at clarifying the role of benzyl isothiocyanate (BITC). As secondary parameters leukotriene 4 (LTB4), and cytokine release (tumor necrosis factor alpha, TNF-α; interleukins IL-1β, IL-10, and IL-12) were quantified.

Methods and results

Thirty-four healthy female participants consumed 1.5 g nasturtium containing BITC, (verum) or no BITC (control) twice a day for 2 weeks each. Nasturtium intervention resulted in an increase in mean PGE2 levels in serum samples (verum: 1.76-fold, p ≤ 0.05; control: 1.78-fold, p ≤ 0.01), and ex vivo stimulated peripheral blood mononuclear cells (PBMC) (verum: 1.71-fold, p ≤ 0.01; control: 1.43-fold). Using a pre-to-post responder analysis approach, 18 of 34 subjects showed a > 25% PGE2 increase in serum, while it was >25% decreased for 9 subjects (stimulated PBMC: 14 and 8 of 28, respectively). Under the selected conditions, the BITC content of nasturtium did not affect the observed changes in PGE2. Verum intervention also increased mean LTB4 serum level (1.24-fold, p ≤ 0.01), but not in LPS stimulated PBMC, and significantly increased TNF-α release in stimulated PBMC after 3 h (verum: 1.65-fold, p = 0.0032; control: 1.22-fold, p = 0.7818). No change was seen in the anti-inflammatory cytokine IL-10, or the pro-inflammatory cytokines IL-1β, and IL-12.

Conclusion

In contrast to the previously reported in vitro results, on average, LPS activated PBMC and serum from both groups showed increased PGE2 levels. Further analyses suggest that PGE2 release after intervention could possibly depend on the baseline PGE2 level. Identification of phenotypes that respond differently to the nasturtium intervention could be useful to establish personalized approaches for dosing phytopharmaceuticals medicines.

Interaction between APOE, APOA1, and LPL Gene Polymorphisms and Variability in Changes in Lipid and Blood Pressure following Orange Juice Intake: A Pilot Study

SCOPE

Chronic orange juice intake is associated with reduced risk of cardiovascular disease, however, a large inter-individual variability in response to orange juice for lipid profile and blood pressure has been observed. This heterogeneity in responsiveness could be associated with single nucleotide polymorphism (SNP), which has not been previously addressed. This study aims to investigate the influence of SNP in apolipoprotein E (APOE), apolipoprotein A1 (APOA1), mevalonate (MVK), and lipase lipoprotein (LPL) genes in the biological response after chronic orange juice intake.

METHODS AND RESULTS

Forty-six volunteers ingested 500 mL daily for 60 days and blood pressure and biochemical parameters are measured. Also, SNPs in APOE, APOA1, MVK, and LPL genes are genotyped in the volunteers that are medium/high excretors of flavanone metabolites. Genotypes CC (APOA1), AA, and GG (LPL) are associated with positive health effects of orange juice and the CC (APOE), GG (APOA1), GG, and AA (LPL) genotypes are associated with no effects of orange juice consumption (p < 0.05).

CONCLUSION

These results identify for the first-time SNP associated with effects of orange juice on lipid levels and blood pressure, results that may provide bases for future precise nutritional recommendations regarding this flavanone-rich food to lower the risk for cardiovascular disease.

The synergistic ramification of insoluble dietary fiber and associated non-extractable polyphenols on gut microbial population escorting alleviation of lifestyle diseases

Most of the pertinent research which aims at exploring the therapeutic effects of polyphenols usually misapprehends a large fraction of non-extractable polyphenols due to their poor aqueous-organic solvent extractability. These polymeric polyphenols (i.e., proanthocyanins, hydrolysable tannins and phenolic acids) possess a unique property to adhere to the food matrix polysaccharides and protein sowing to their structural complexity with high glycosylation, degree of polymerization, and plenty of hydroxyl groups. Surprisingly resistance to intestinal absorption does not hinder its bioactivity but accelerates its functionality manifolds due to the colonic microbial catabolism in the gastrointestinal tract, thereby protecting the body from local and systemic inflammatory diseases. This review highlights not only the chemistry, digestion, colonic metabolism of non-extractable polyphenols (NEPP) but also summarises the synergistic effect of matrix-bound NEPP exerting local as well as systemic health benefits.

A grape seed and bilberry extract reduces blood pressure in individuals at risk of developing type 2 diabetes: the PRECISE study, a double-blind placebo-controlled cross-over intervention study

Background

Type 2 Diabetes Mellitus (T2DM) is a major risk factor for the development of cardiometabolic diseases. T2DM prevention is largely based on weight-loss and whole diet changes, but intervention with dietary plant bioactives may also improve metabolic health.

Objective

To assess whether supplementation with bilberry and grape seed extract for 12 weeks improves cardiometabolic outcomes in individuals at risk of developing T2DM, and to determine whether individual treatment response is associated with differences in gut microbiota composition and levels of phenolic metabolites in blood and feces.

Methods

In the randomized, double-blind, placebo-controlled, cross-over PRECISE intervention study, 14 participants, aged ≥45 years, with a BMI >28 kg/m², and having an increased risk of T2DM, received a supplement containing 250 mg of bilberry plus 300 mg of grape seed extract, or 550 mg of a control extract, per day, for 12 weeks each. Blood samples were obtained for the assessment of HbA1c, fasting glucose, oral glucose tolerance tests, insulin, glucagon levels, total, LDL and HDL cholesterol, and phenolic acids. We also assessed advanced glycation end products in the skin, ambulatory 24 hours blood pressure, 7-day dietary intake by weighed food diaries, fecal levels of phenolic metabolites using LC-MS/MS and gut microbiota composition using 16S rRNA gene sequencing analysis.

Results

The combined bilberry and grape seed extract did not affect glucose and cholesterol outcomes, but it decreased systolic and diastolic ambulatory blood pressure by 4.7 (p < 0.001) and 2.3 (p = 0.0009) mmHg, respectively. Eight out of fourteen participants were identified as blood pressure 'responders'. These responders had higher levels of phenylpropionic and phenyllactic acids in their fecal samples, and a higher proportional abundance of Fusicatenibacter-related bacteria (p < 0.01) in their baseline stool samples.

Conclusion

Long-term supplementation with bilberry and grape seed extract can improve systolic and diastolic blood pressure in individuals at risk of T2DM. Individual responsiveness was correlated with the presence of certain fecal bacterial strains, and an ability to metabolize (epi)catechin into smaller phenolic metabolites.Clinical trial registry number: Research Registry (number 4084).

Dietary Supplements Containing Oat Beta-Glucan and/or Green Coffee (Poly)phenols Showed Limited Effect in Modulating Cardiometabolic Risk Biomarkers in Overweight/Obese Patients without a Lifestyle Intervention

Obesity has reached pandemic proportions and has become a major health concern worldwide. Therefore, it is necessary to find new strategies against this condition and its associated comorbidities. Green coffee polyphenols (GCP) and oat beta-glucans (BGs) have proven their hypolipidaemic and hypoglycaemic effects. This study aimed to examine the effects of the long-term consumption of supplements containing GCP, BG or the novel GCP/BG combination on lipid and glucose metabolism biomarkers in overweight/obese subjects who maintained their dietary habits and physical activity, hence addressing the difficulty that this population faces in adapting to lifestyle changes. A randomised, crossover, blind trial was carried out in 29 volunteers who consumed either GCP (300 mg), BG (2.5 g) or GCP/BG (300 mg + 2.5 g) twice a day for 8 weeks. Blood samples were collected, and blood pressure and body composition were measured at the beginning and end of each intervention. Total cholesterol, triglycerides, high-density lipoprotein (HDL-C), low-density lipoprotein (LDL-C), very low-density lipoprotein (VLDL-C) cholesterol, glycated haemoglobin, fasting glucose, insulin, aspartate transaminase, alanine transaminase and different hormones and adipokines were analysed. Only VLDL-C (p = 0.01) and diastolic blood pressure (p = 0.027) decreased after the intervention, especially with the BG supplement. There were no other significant changes in the analysed biomarkers. In conclusion, the regular intake of GCP, BG and GCP/BG without lifestyle changes is not an efficient strategy to improve lipid and glucose homeostasis in overweight/obese subjects.

Potential Benefits of Antioxidant Phytochemicals on Endogenous Antioxidants Defences in Chronic Diseases

Chronic diseases and cancer are worldwide health problems which result in death and disability for millions of people [...]

Total urinary polyphenol excretion: a biomarker of an anti-inflammatory diet and metabolic syndrome status

BACKGROUND

Chronic inflammation is associated with noncommunicable diseases, including obesity, metabolic syndrome (MetS), and CVDs. The Mediterranean diet has been shown to have strong anti-inflammatory effects, attributed in part to the polyphenol richness of many of its components.

OBJECTIVES

This study aimed to assess the value of polyphenols as a urinary biomarker of an anti-inflammatory diet and their influence on MetS status.

METHODS

A longitudinal analysis was performed in Spain considering 543 participants with high CVD risk in a PREDIMED study. Approximately 52% of the participants were women and 48% were men with a mean age of 67.5 (5.9) y. Total polyphenol excretion (TPE) in urine was determined at baseline and 5 y of intervention using a validated Folin-Ciocalteu spectrophotometric method, and the dietary inflammatory index (DII) was calculated from a validated 137-item food-frequency questionnaire. Three categories were built according to tertiles of change in the DII score. Multivariable linear regression analyses were performed to assess the association of changes in TPE with changes in the DII scores and with MetS status at 5 y.

RESULTS

Tertiles 2 and 3 compared with tertile 1 presented a lower anti-inflammatory potential of the diet and were inversely associated with TPE in women [-0.30 mg gallic acid equivalent (GAE)/g creatinine; 95% CI: -0.46, -0.15; P value = 0.006 and -0.29 mg GAE/g creatinine; 95% CI: -0.43, -0.15; P value = 0.005], respectively. The mean changes in TPE were 7.9 (56.1) mg GAE/g creatinine in women and 7.7 (48.2) mg GAE/g creatinine in men. In addition, TPE was inversely associated with changes in MetS status [-0.06 (-0.09; -0.02), P value = 0.009] in both men and women.

CONCLUSIONS

Urinary polyphenols may be a potential biomarker of anti-inflammatory diet consumption in women and are prospectively associated with improvement in MetS.

Review: Harmonised in vitro digestion and the Ussing chamber for investigating the effects of polyphenols on intestinal physiology in monogastrics and ruminants

Because of the relevant effects of plant-derived polyphenols (PPs) on monogastrics and ruminants' nutrition, emissions and performance, an increasing number of in vivo and in vitro studies are being performed to better understand the mechanisms of action of polyphenols at both the ruminal and intestinal levels. The biological properties of these phenolic compounds strongly depend on their degradation, absorption and metabolism. The harmonised in vitro digestion method (INFOGEST) is one of the most reliable in vitro methods used to assess the bioaccessibility and or antioxidant activity of PP contained in different matrixes, as well as the interactions of PP and their degradation products with other feed ingredients. The effects of PP released from their matrix after in vitro digestion on different intestinal physiological parameters, such as epithelium integrity, can be further evaluated by the use of ex vivo models such as the Ussing chamber. This review aims to describe the combination of the INFOGEST method, coupled with the Ussing chamber as a valuable model for the digestion and subsequent effects and absorption of phenolic compounds in monogastrics and potentially in ruminants. The advances, challenges and limits of this approach are also discussed.

Current challenges and future implications of exploiting the omics data into nutrigenetics and nutrigenomics for personalized diagnosis and nutrition-based care

Nutrigenetics and nutrigenomics, combined with the omics technologies, are a demanding and an increasingly important field in personalizing nutrition-based care to understand an individual's response to nutrition-guided therapy. Omics is defined as the analysis of the large data sets of the biological system featuring transcriptomics, proteomics, and metabolomics and providing new insights into cell regulation. The effect of combining nutrigenetics and nutrigenomics with omics will give insight into molecular analysis, as human nutrition requirements vary per individual. Omics measures modest intraindividual variability and is critical to exploit these data for use in the development of precision nutrition. Omics, combined with nutrigenetics and nutrigenomics, is instrumental in the creation of goals for improving the accuracy of nutrition evaluations. Although dietary-based therapies are provided for various clinical conditions such as inborn errors of metabolism, limited advancement has been done to expand the omics data for a more mechanistic understanding of cellular networks dependent on nutrition-based expression and overall regulation of genes. The greatest challenge remains in the clinical sector to integrate the current data available, overcome the well-established limits of self-reported methods in research, and provide omics data, combined with nutrigenetics and nutrigenomics research, for each individual. Hence, the future seems promising if a design for personalized, nutrition-based diagnosis and care can be implemented practically in the health care sector.

Absorption, metabolism, bioactivity, and biotransformation of epigallocatechin gallate

Epigallocatechin gallate (EGCG), a typical flavone-3-ol polyphenol containing eight free hydroxyl groups, is associated with a variety of bioactivities, such as antioxidant, anti-inflammatory, anti-cancer, and antibacterial activities. However, the poor bioavailability of EGCG restricts its use. In this review, we discuss the processes involved in the absorption and metabolism of EGCG, with a focus on its metabolic interactions with the gut microbiota. Next, we summarize the bioactivities of some key metabolites, describe the biotransformation of EGCG by different microorganisms, and discuss its catabolism by specific bacteria. A deeper understanding of the absorption, metabolism, and biotransformation of EGCG may enable its disease-preventive and therapeutic properties to be better utilized. This review provides a theoretical basis for further development and utilization of EGCG and its metabolites for improving the gut microbiota and physiological health.

Antioxidant Phytochemicals as Potential Therapy for Diabetic Complications

The global prevalence of diabetes continues to increase partly due to rapid urbanization and an increase in the aging population. Consequently, this is associated with a parallel increase in the prevalence of diabetic vascular complications which significantly worsen the burden of diabetes. For these diabetic vascular complications, there is still an unmet need for safe and effective alternative/adjuvant therapeutic interventions. There is also an increasing urge for therapeutic options to come from natural products such as plants. Hyperglycemia-induced oxidative stress is central to the development of diabetes and diabetic complications. Furthermore, oxidative stress-induced inflammation and insulin resistance are central to endothelial damage and the progression of diabetic complications. Human and animal studies have shown that polyphenols could reduce oxidative stress, hyperglycemia, and prevent diabetic complications including diabetic retinopathy, diabetic nephropathy, and diabetic peripheral neuropathy. Part of the therapeutic effects of polyphenols is attributed to their modulatory effect on endogenous antioxidant systems. This review attempts to summarize the established effects of polyphenols on endogenous antioxidant systems from the literature. Moreover, potential therapeutic strategies for harnessing the potential benefits of polyphenols for diabetic vascular complications are also discussed.

Identification of D-Limonene Metabolites by LC-HRMS: An Exploratory Metabolic Switching Approach in a Mouse Model of Diet-Induced Obesity

Metabolic switching has been raised as an important phenomenon to be studied in relation to xenobiotic metabolites, since the dose of the exposure determines the formation of metabolites and their bioactivity. Limonene is a monoterpene mostly found in citrus fruits with health activity, and its phase II metabolites and activity are still not clear. The aim of this work was to evaluate the effects of D-limonene in the development of diet-induced obesity in mice and to investigate metabolites that could be generated in a study assessing different doses of supplementation. Animals were induced to obesity and supplemented with 0.1% or 0.8% D-limonene added to the feed. Limonene phase I and II metabolites were identified in liver and urine by LC-ESI-qToF-MS/MS. To the best of our knowledge, in this study three new phase I metabolites and ten different phase II metabolites were first attributed to D-limonene. Supplementation with 0.1% D-limonene was associated with lower weight gain and a trend to lower accumulation of adipose tissue deposits. The metabolites limonene-8,9-diol, perillic acid and perillic acid-8,9-diol should be explored in future research as anti-obesogenic agents as they were the metabolites most abundant in the urine of mice that received 0.1% D-limonene in their feed.

Effects of Polyphenols on Glucose-Induced Metabolic Changes in Healthy Human Subjects and on Glucose Transporters

Dietary polyphenols interact with glucose transporters in the small intestine and modulate glucose uptake after food or beverage consumption. This review assesses the transporter interaction in vitro and how this translates to an effect in healthy volunteers consuming glucose. As examples, the apple polyphenol phlorizin inhibits sodium-glucose linked transporter-1; in the intestinal lumen, it is converted to phloretin, a strong inhibitor of glucose transporter-2 (GLUT2), by the brush border digestive enzyme lactase. Consequently, an apple extract rich in phlorizin attenuates blood glucose and insulin in healthy volunteers after a glucose challenge. On the other hand, the olive phenolic, oleuropein, inhibits GLUT2, but the strength of the inhibition is not enough to modulate blood glucose after a glucose challenge in healthy volunteers. Multiple metabolic effects and oxidative stresses after glucose consumption include insulin, incretin hormones, fatty acids, amino acids, and protein markers. However, apart from acute postprandial effects on glucose, insulin, and some incretin hormones, very little is known about the acute effects of polyphenols on these glucose-induced secondary effects. In summary, attenuation of the effect of a glucose challenge in vivo is only observed when polyphenols are strong inhibitors of glucose transporters.

A look beyond dietary (poly)phenols: The low molecular weight phenolic metabolites and their concentrations in human circulation

A large number of epidemiological studies have shown that consumption of fruits, vegetables, and beverages rich in (poly)phenols promote numerous health benefits from cardiovascular to neurological diseases. Evidence on (poly)phenols has been applied mainly to flavonoids, yet the role of phenolic acids has been largely overlooked. Such phenolics present in food combine with those resulting from gut microbiota catabolism of flavonoids and chlorogenic acids and those produced by endogenous pathways, resulting in large concentrations of low molecular weight phenolic metabolites in human circulation. Independently of the origin, in human intervention studies using diets rich in (poly)phenols, a total of 137 low molecular weight phenolic metabolites have been detected and quantified in human circulation with largely unknown biological function. In this review, we will pinpoint two main aspects of the low molecular weight phenolic metabolites: (i) the microbiota responsible for their generation, and (ii) the analysis (quali- and quantitative) in human circulation and their respective pharmacokinetics. In doing so, we aim to drive scientific advances regarding the ubiquitous roles of low molecular weight phenolic metabolites using physiologically relevant concentrations and under (patho)physiologically relevant conditions in humans.

The effect of malting on phenolic compounds and radical scavenging activity in grains and breakfast cereals

Breakfast cereals are popular grain foods and sources of polyphenols. Malting alters polyphenol content and activity; however, effects are varied. The total polyphenol content (TPC), radical scavenging activity (RSA), and polyphenol profile were analyzed in unmalted and malted grains (wheat, barley, and sorghum) and breakfast cereals (wheat, barley) by Folin Ciocalteu Reagent (FCR), % inhibition of the free radical 2,2-diphenyl-1-picryl-hydrazyl, and high performance liquid chromatography. Higher TPC was observed in all malted grains and breakfast cereals compared with unmalted samples (p < 0.05). Higher RSA was also observed in all malted samples compared to unmalted samples (p < 0.05) except for wheat grain to malted wheat grain. In this study, malting induced additional polyphenols and antioxidant activity in grains and cereal products. Malted grain breakfast cereals may be practical sources of polyphenol antioxidants. PRACTICAL APPLICATION: This study utilized malting in a unique way to investigate potential health benefits of polyphenols and antioxidant activity in grains (wheat, barley, and sorghum) and ready-to-eat breakfast cereals (wheat and barley). This study found that grains and breakfast cereals are important sources of antioxidant polyphenols, and these were significantly increased in malted varieties. Understanding this is important as grains and breakfast cereals are widely consumed staple foods. Consuming healthier grain products may be a practical strategy in reducing the risk of noncommunicable diseases such as colorectal cancer and type-2 diabetes, where wholegrain consumption may be important in prevention.

Determination of factors associated with serum cholesterol response to dairy fat consumption in overweight adults: Secondary analysis from an RCT

Elevated intakes of saturated fatty acids (SFA) can adversely affect serum cholesterol levels. Dairy fat contains ~60% SFA, prompting healthy eating guidelines to recommend low-fat dairy. Physiological, and environmental factors influence inter-individual variance in response to food consumption. Evidence exploring the dairy matrix has differing effects of dairy fat consumption on serum cholesterol levels when consumed in the form of cheese. The extent of this variability and determinants of response to dairy fat are currently unknown. The objective of this study was to determine factors associated with lipid metabolism response to a dairy fat intervention, with a focus on serum cholesterol. A 6-week randomized parallel intervention trial was carried out in healthy volunteers (≥50 years, BMI ≥25 kg/m²). Participants (n = 104) consumed ~40 g dairy fat daily in addition to their usual diet, in 1 of 3 forms: butter, cheese, or reduced-fat cheese and butter. For this analysis, “response” was based on the percentage (%) change in serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) from pre- to post-intervention. Participants were divided into tertiles for each lipid response. The upper and lower tertiles were used to categorize participants as “responders” and “non-responders.” For TC and LDL-c, response was classified as a decrease, whereas “response” was defined as an increase for HDL-c. Clinical response was also considered, by calculating pre- and post-intervention prevalence of those meeting target levels of cholesterol recommendations. Participants demonstrating the largest % decrease (Tertile 1; “responders”) in TC had significantly higher levels of TC and HDL-c, at baseline, and lower levels of triglycerides (TAGs) compared to those in tertile 3 (i.e., TC non-responders). Those with the largest % decrease in LDL-c (Tertile 1: LDL-c responders) had higher baseline levels of LDL-c and lower levels of TAGs. Multiple regression analysis revealed that the % change in TC and LDL-c was associated with baseline TC, TAG, body weight and high-sensitivity C-reactive protein (hsCRP; P < 0.05). Previous work has demonstrated the dairy food matrix affects lipid response to dairy consumption. This study suggests that phenotypic differences may also influence response to dairy fat in overweight individuals.

Phytonutrients: Sources, bioavailability, interaction with gut microbiota, and their impacts on human health

Phytonutrients are natural bioactive components present in the daily diet that can exert a positive impact on human health. Studies have shown that phytonutrients may act as antioxidants and improve metabolism after being ingested, which help to regulate physiological processes and prevent metabolic disorders and diseases. However, their efficacy is limited by their low bioavailability. The gut microbiota is symbiotic with humans and its abundance and profile are related to most diseases. Interestingly, studies have shown that the gut microbiota is associated with the metabolism of phytonutrients by converting them into small molecules that can be absorbed by the body, thereby enhancing their bioavailability. Furthermore, phytonutrients can modulate the composition of the gut microbiota, and therefore improve the host's health. Here, we focus on uncovering the mechanisms by which phytonutrients and gut microbiota play roles in health, and the interrelationships between phytonutrients and gut microbiota were summarized. We also reviewed the studies that reported the efficacy of phytonutrients in human health and the future directions.

Non-Celiac Gluten Sensitivity and Protective Role of Dietary Polyphenols

Pathogenetically characterized by the absence of celiac disease and wheat allergy, non-celiac gluten sensitivity (NCGS) is a clinical entity triggered by the consumption of gluten-containing foods that relieved by a gluten-free diet. Since it is very difficult to maintain a complete gluten-free diet, there is a high interest in discovering alternative strategies aimed at reducing gluten concentration or mitigating its toxic effects. Plant-based dietary models are usually rich in bioactive compounds, such as polyphenols, recognized to prevent, delay, or even reverse chronic diseases, including intestinal disorders. However, research on the role of polyphenols in mitigating the toxicity of gluten-containing foods is currently limited. We address the metabolic fate of dietary polyphenols, both as free and bound macromolecule-linked forms, with particular reference to the gastrointestinal compartment, where the concentration of polyphenols can reach high levels. We analyze the potential targets of polyphenols including the gluten peptide bioavailability, the dysfunction of the intestinal epithelial barrier, intestinal immune response, oxidative stress and inflammation, and dysbiosis. Overall, this review provides an updated overview of the effects of polyphenols as possible dietary strategies to counteract the toxic effects of gluten, potentially resulting in the improved quality of life of patients with gluten-related disorders.

Sustained Consumption of a Decaffeinated Green Coffee Nutraceutical Has Limited Effects on Phenolic Metabolism and Bioavailability in Overweight/Obese Subjects

Knowledge on the bioavailability of coffee (poly)phenols mostly come from single dose postprandial studies. This study aimed at investigating the effects of regularly consuming a green coffee phenolic extract (GCPE) on the bioavailability and metabolism of (poly)phenols. Volunteers with overweight/obesity consumed a decaffeinated GCPE nutraceutical containing 300 mg hydroxycinnamates twice daily for two months. Plasma and urinary pharmacokinetics, and fecal excretion of phenolic metabolites were characterized by LC-MS-QToF at weeks 0 and 8. Fifty-four metabolites were identified in biological fluids. Regular consumption of the nutraceutical produced certain changes: reduced forms of caffeic, ferulic and coumaric acids in urine or 3-(3′-hydroxypenyl)propanoic, and 3,4-dihydroxybenzoic acids in feces significantly increased (p < 0.05) after 8 weeks; in contrast, coumaroylquinic and dihydrocoumaroylquinic acids in urine decreased (p < 0.05) compared to baseline excretion. The sum of intestinal and colonic metabolites increased after sustained consumption of GCPE, without reaching statistical significance, suggesting a small overall effect on (poly)phenols’ bioavailability.

Variability in the Beneficial Effects of Phenolic Compounds: A Review

When analysing the beneficial effects of phenolic compounds, several factors that exert a clear influence should be taken into account. The content of phenolic compounds in foods is highly variable, directly affecting individual dietary intake. Once ingested, these compounds have a greater or lesser bioaccessibility, defined as the amount available for absorption in the intestine after digestion, and a certain bioavailability, defined as the proportion of the molecule that is available after digestion, absorption and metabolism. Among the external factors that modify the content of phenolic compounds in food are the variety, the cultivation technique and the climate. Regarding functional foods, it is important to take into account the role of the selected food matrix, such as dairy matrices, liquid or solid matrices. It is also essential to consider the interactions between phenolic compounds as well as the interplay that occurs between these and several other components of the diet (macro- and micronutrients) at absorption, metabolism and mechanism of action levels. Furthermore, there is a great inter-individual variability in terms of phase II metabolism of these compounds, composition of the microbiota, and metabolic state or metabotype to which the subject belongs. All these factors introduce variability in the responses observed after ingestion of foods or nutraceuticals containing phenolic compounds.

Quercetin Mitigates Endothelial Activation in a Novel Intestinal-Endothelial-Monocyte/Macrophage Coculture Setup

Atherosclerosis initiation is associated with a pro-inflammatory state of the endothelium. Quercetin is a flavonoid abundantly present in plant-based foods, with a possible impact on cardiovascular health. In this study, the effects of quercetin on lipopolysaccharide (LPS)-mediated endothelial inflammation and monocyte adhesion and migration, which are initial steps of the atherogenic process, are studied. Novel in vitro multicellular models simulating the intestinal-endothelial-monocytes/macrophages axis allowed to combine relevant intestinal flavonoid absorption, metabolism and efflux, and the consequent bioactivity towards peripheral endothelial cells. In this triple coculture, quercetin exposure decreased monocyte adhesion to and macrophage migration through an LPS-stressed endothelium, and this was associated with significantly lower levels of soluble vascular cell adhesion molecule-1 (sVCAM-1). Furthermore, quercetin decreased the pro-inflammatory cell environment upon LPS-induced endothelial activation, in terms of tumor necrosis factor- α (TNF-α), interleukin-6 (IL-6), interleukin-8 (IL-8), and sVCAM-1 expression. These findings highlight a mode-of-action by which quercetin may positively impact the initial states of atherosclerosis under more physiologically relevant conditions in terms of quercetin concentrations, metabolites, and intercellular crosstalk.

The intake of flavonoids, stilbenes, and tyrosols, mainly consumed through red wine and virgin olive oil, is associated with lower carotid and femoral subclinical atherosclerosis and coronary calcium

Purpose

It is suggested that polyphenols back the cardiovascular protection offered by the Mediterranean diet. This study evaluates the association of specific types of dietary polyphenols with prevalent subclinical atherosclerosis in middle-aged subjects.

Methods

Ultrasonography and TC were performed on 2318 men from the Aragon Workers Health Study, recruited between 2011 and 2014, to assess the presence of plaques in carotid and femoral arteries and coronary calcium. Polyphenol intake was assessed using a validated semi-quantitative 136-item food frequency questionnaire. The Phenol Explorer database was used to derive polyphenol class intake. Logistic and linear regressions were used to estimate the cross-sectional association of polyphenols intake with femoral and carotid subclinical atherosclerosis and coronary calcium.

Results

A higher intake of flavonoids (third vs. first tertile) was associated with a lower risk of both carotid (OR 0.80: CI 95% 0.62–1.02; P trend 0.094) and femoral (0.62: 0.48–0.80, P trend < 0.001) subclinical atherosclerosis. A higher intake of stilbenes was associated with a lower risk of femoral subclinical atherosclerosis (0.62: 0.46–0.83; P trend 0.009) and positive coronary calcium (0.75: 0.55–1.03; P trend 0.131). A higher intake of tyrosols was also associated with a lower risk of positive coronary calcium (0.80: 0.62–1.03; P trend 0.111). The associations remained similar when adjusted for blood lipids and blood pressure.

Conclusion

Dietary flavonoids, stilbenes, and tyrosols, whose main sources are red wine and virgin olive oil, are associated with lower prevalence of subclinical atherosclerosis in middle-aged subjects.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-022-02823-0.

Technological and Biotechnological Processes To Enhance the Bioavailability of Dietary (Poly)phenols in Humans

The health effects of (poly)phenols (PPs) depend upon their bioavailability that, in general, is very low and shows a high interindividual variability. The low bioavailability of PPs is mainly attributed to their low absorption in the upper gastrointestinal tract as a result of their low water solubility, their presence in foods as polymers or in glycosylated forms, and their tight bond to food matrices. Although many studies have investigated how technological and biotechnological processes affect the phenolic composition of fruits and vegetables, limited information exists regarding their effects on PP bioavailability in humans. In the present review, the effect of food processing (mechanical, thermal, and non-thermal treatments), oral-delivery nanoformulations, enzymatic hydrolysis, fermentation, co-administration with probiotics, and generation of postbiotics in PP bioavailability have been overviewed, focusing in the evidence provided in humans.

The Donor-Dependent and Colon-Region-Dependent Metabolism of (+)-Catechin by Colonic Microbiota in the Simulator of the Human Intestinal Microbial Ecosystem

The intestinal absorption of dietary catechins is quite low, resulting in most of them being metabolized by gut microbiota in the colon. It has been hypothesized that microbiota-derived metabolites may be partly responsible for the association between catechin consumption and beneficial cardiometabolic effects. Given the profound differences in gut microbiota composition and microbial load between individuals and across different colon regions, this study examined how microbial (+)-catechin metabolite profiles differ between colon regions and individuals. Batch exploration of the interindividual variability in (+)-catechin microbial metabolism resulted in a stratification based on metabolic efficiency: from the 12 tested donor microbiota, we identified a fast- and a slow-converting microbiota that was subsequently inoculated to SHIME, a dynamic model of the human gut. Monitoring of microbial (+)-catechin metabolites from proximal and distal colon compartments with UHPLC-MS and UPLC-IMS-Q-TOF-MS revealed profound donor-dependent and colon-region-dependent metabolite profiles with 5-(3',4'-dihydroxyphenyl)-γ-valerolactone being the largest contributor to differences between the fast- and slow-converting microbiota and the distal colon being a more important region for (+)-catechin metabolism than the proximal colon. Our findings may contribute to further understanding the role of the gut microbiota as a determinant of interindividual variation in pharmacokinetics upon (+)-catechin ingestion.

A High Protein Diet Is More Effective in Improving Insulin Resistance and Glycemic Variability Compared to a Mediterranean Diet-A Cross-Over Controlled Inpatient Dietary Study

The optimal dietary pattern to improve metabolic function remains elusive. In a 21-day randomized controlled inpatient crossover feeding trial of 20 insulin-resistant obese women, we assessed the extent to which two isocaloric dietary interventions—Mediterranean (M) and high protein (HP)—improved metabolic parameters. Obese women were assigned to one of the following dietary sequences: M–HP or HP–M. Cardiometabolic parameters, body weight, glucose monitoring and gut microbiome composition were assessed. Sixteen women completed the study. Compared to the M diet, the HP diet was more effective in (i) reducing insulin resistance (insulin: Beta (95% CI) = −6.98 (−12.30, −1.65) µIU/mL, p = 0.01; HOMA-IR: −1.78 (95% CI: −3.03, −0.52), p = 9 × 10⁻³); and (ii) improving glycemic variability (−3.13 (−4.60, −1.67) mg/dL, p = 4 × 10⁻⁴), a risk factor for T2D development. We then identified a panel of 10 microbial genera predictive of the difference in glycemic variability between the two diets. These include the genera Coprococcus and Lachnoclostridium, previously associated with glucose homeostasis and insulin resistance. Our results suggest that morbidly obese women with insulin resistance can achieve better control of insulin resistance and glycemic variability on a high HP diet compared to an M diet.

A Systematic Review of the Cardiometabolic Benefits of Plant Products Containing Mixed Phenolics and Polyphenols in Postmenopausal Women: Insufficient Evidence for Recommendations to This Specific Population

Menopause is characterized by endocrine and physiological changes and is often accompanied by increased body weight and cholesterol, glucose intolerance, and/or hypertension. These alterations are associated with increased risk for cardiovascular diseases (CVDs) and Type II diabetes mellitus (T2DM) that may be moderate by dietary plant phenolic compounds. In this review, we examine the current evidence of the impact of a variety of plant products (foods, extracts, beverages) rich in a mixture of phenolics and polyphenols on: (i) glucose and insulin levels; (ii) lipid profile; (iii) blood pressure; and (iv) biomarkers of inflammation and oxidative stress in postmenopausal women. We critically evaluate both the results of a range of intervention studies conducted in this specific subpopulation and the level of evidence supporting the benefits of consuming those products after the menopause. Overall, the current available evidence does not allow for specific dietary recommendations of these plant products rich in phenolics and polyphenols in this high-risk subpopulation. Our data show rather variable and small effects of the different products examined on the cardiometabolic biomarkers and further support the need to: (1) improve the quality of the study designs and data reporting; and (2) understand the variability in the response of the different biomarkers and establish clear differences between healthy and cardiometabolic disease levels.