Effect of a wild blueberry (Vaccinium angustifolium) drink intervention on markers of oxidative stress, inflammation and endothelial function in humans with cardiovascular risk factors

Dietary Strawberries Improve Biomarkers of Antioxidant Status and Endothelial Function in Adults with Cardiometabolic Risks in a Randomized Controlled Crossover Trial

Strawberries, a popularly consumed berry fruit, are rich in bioactive compounds with antioxidant effects. In this study, we examined the effects of two dietary achievable doses of strawberries on the antioxidant status and biomarkers of endothelial function in adults with features of metabolic syndrome and a confirmed low baseline of fruit and vegetable intake. In a 14-week randomized controlled crossover study, participants were assigned to one of three groups for four weeks separated by a one-week washout period: control powder, one serving (low dose: 13 g strawberry powder/day), or 2.5 servings (high dose: 32 g strawberry powder/day). Blood samples and health data were collected at baseline and at the end of each four-week phase of intervention. Thirty-three participants completed all three phases of the trial. Significant increases were observed in serum antioxidant capacity and superoxide dismutase activity as well as decreases in lipid peroxidation after both low and high dose strawberry phases when compared with the control phase. Significant decreases were also observed in soluble vascular cell adhesion molecule-1 and tumor necrosis factor-α with the high dose strawberry phase. These data confirm that consuming strawberries for four weeks significantly improves antioxidant status, endothelial function, and inflammation in adults with cardiometabolic risks.

Antioxidant properties of anthocyanins and their mechanism of action in atherosclerosis

Atherosclerosis develops due to lipid accumulation in the arterial wall and sclerosis as result of increased hyperlipidemia, oxidative stress, lipid oxidation, and protein oxidation. However, improving antioxidant status through diet may prevent the progression of atherosclerotic cardiovascular disease. It is believed that polyphenol-rich plants contribute to the inverse relationship between fruit and vegetable intake and chronic disease. Anthocyanins are flavonoid polyphenols with antioxidant properties that have been associated with reduced risk of cardiovascular disease. The consumption of anthocyanins increases total antioxidant capacity, antioxidant defense enzymes, and HDL antioxidant properties by several measures in preclinical and clinical populations. Anthocyanins appear to impart antioxidant actions via direct antioxidant properties, as well as indirectly via inducing intracellular Nrf2 activation and antioxidant gene expression. These actions counter oxidative stress and inflammatory signaling in cells present in atherosclerotic plaques, including macrophages and endothelial cells. Overall, anthocyanins may protect against atherosclerosis and cardiovascular disease through their effects on cellular antioxidant status, oxidative stress, and inflammation; however, their underlying mechanisms of action appear to be complex and require further elucidation.

Effect of Coffee and Cocoa-Based Confectionery Containing Coffee on Markers of DNA Damage and Lipid Peroxidation Products: Results from a Human Intervention Study

The effect of coffee and cocoa on oxidative damage to macromolecules has been investigated in several studies, often with controversial results. This study aimed to investigate the effect of one-month consumption of different doses of coffee or cocoa-based products containing coffee on markers of DNA damage and lipid peroxidation in young healthy volunteers. Twenty-one volunteers were randomly assigned into a three-arm, crossover, randomized trial. Subjects were assigned to consume one of the three following treatments: one cup of espresso coffee/day (1C), three cups of espresso coffee/day (3C), and one cup of espresso coffee plus two cocoa-based products containing coffee (PC) twice per day for 1 month. At the end of each treatment, blood samples were collected for the analysis of endogenous and H2O2-induced DNA damage and DNA oxidation catabolites, while urines were used for the analysis of oxylipins. On the whole, four DNA catabolites (cyclic guanosine monophosphate (cGMP), 8-OH-2'-deoxy-guanosine, 8-OH-guanine, and 8-NO2-cGMP) were detected in plasma samples following the one-month intervention. No significant modulation of DNA and lipid damage markers was documented among groups, apart from an effect of time for DNA strand breaks and some markers of lipid peroxidation. In conclusion, the consumption of coffee and cocoa-based confectionery containing coffee was apparently not able to affect oxidative stress markers. More studies are encouraged to better explain the findings obtained and to understand the impact of different dosages of these products on specific target groups.

Review of Functional and Pharmacological Activities of Berries

Functional plant-based foods (such as fruits, vegetables, and berries) can improve health, have a preventive effect, and diminish the risk of different chronic diseases during in vivo and in vitro studies. Berries contain many phytochemicals, fibers, vitamins, and minerals. The primary phytochemicals in berry fruits are phenolic compounds including flavonoids (anthocyanins, flavonols, flavones, flavanols, flavanones, and isoflavonoids), tannins, and phenolic acids. Since berries have a high concentration of polyphenols, it is possible to use them for treating various diseases pharmacologically by acting on oxidative stress and inflammation, which are often the leading causes of diabetes, neurological, cardiovascular diseases, and cancer. This review examines commonly consumed berries: blackberries, blackcurrants, blueberries, cranberries, raspberries, black raspberries, and strawberries and their polyphenols as potential medicinal foods (due to the presence of pharmacologically active compounds) in the treatment of diabetes, cardiovascular problems, and other diseases. Moreover, much attention is paid to the bioavailability of active berry components. Hence, this comprehensive review shows that berries and their bioactive compounds possess medicinal properties and have therapeutic potential. Nevertheless, future clinical trials are required to study and improve the bioavailability of berries' phenolic compounds and extend the evidence that the active compounds of berries can be used as medicinal foods against various diseases.

Effects of Anthocyanin Supplementation on Reduction of Obesity Criteria: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Anthocyanins, water-soluble flavonoids that produce red-to-blue pigment in plants, have antioxidant properties and have been developed as a functional food to fight obesity. In randomized controlled trials (RCTs), a systematic review with meta-analysis (SR-MA) was used to investigate these anti-obesity effects. Using search engines (PubMed, EMBASE, Cochrane-library, and CINAHL) and keywords (anthocyanins, BMI, WC, WHR, and inflammatory biomarkers), 11 out of 642 RCTs (28.3–500 mg/day of anthocyanins for 4 to 24 weeks) were included. The results showed a significant reduction in body mass index (BMI) (MD = −0.36, 95% CI = −0.58 to −0.13), but body weight (BW) and waist circumference (WC) did not change. Anthocyanins decreased BMI in the non-obese (non-OB) group in five RCTs (BMI ≤ 25; MD = −0.40 kg/m²; 95% CI = −0.64 to −0.16;) but did not affect BMI in the obese (OB) group. A subgroup analysis of six RCTs showed that fewer than 300 mg/day reduced BMI (MD = −0.37; 95% CI = −0.06 to −0.14), but ≥300 mg/day did not. A treatment duration of four weeks for four RCTs was sufficient to decrease the BMI (MD = −0.41; 95% CI = −0.66 to −0.16) as opposed to a longer treatment (6–8 or ≥12 weeks). An analysis of the effect of anthocyanins on the BMI showed a significant fall among those from the Middle East compared to those from Asia, Europe, South America, or Oceania. In conclusion, the anthocyanin supplementation of 300 mg/day or less for four weeks was sufficient to reduce the BMI and BW compared to the higher-dose and longer-treatment RCTs. However, further studies might be conducted regarding the dose- or period-dependent responses on various obese biomarkers.

Effects of Berry Anthocyanins on Cognitive Performance, Vascular Function and Cardiometabolic Risk Markers: A Systematic Review of Randomized Placebo-Controlled Intervention Studies in Humans

Supplementation with anthocyanins, which are a type of flavonoids mainly found in various berries, is hypothesized to be a promising approach to lower the risk of developing cognitive decline. The aim of this systematic review was to provide a comprehensive overview of dietary intervention trials describing effects of berry anthocyanins on cognitive performance in humans, while also addressing potential underlying mechanisms. A total of 1197 articles were identified through a systematic search, and 49 studies reporting effects on cognitive performance (n = 18), vascular function (n = 22), or cardiometabolic risk markers (n = 32) were included. Significant improvements were observed on memory, while some of the studies also reported effects on attention and psychomotor speed or executive function. Vascular function markers such as brachial artery flow-mediated vasodilation were also affected and consistent evidence was provided for the beneficial effects of berry anthocyanins on endothelial function. Finally, studies reported improvements in blood pressure, but effects on metabolic risk markers (e.g. carbohydrate and lipid metabolism) were less consistent. In conclusion, this review provides evidence for the beneficial effects of berry anthocyanins on cognitive performance as memory improved. Whether observed anthocyanin-induced improvements in vascular function and blood pressure underlie beneficial effects on cognitive performance warrants further study.

DNA Protection by an Aronia Juice-Based Food Supplement

BACKGROUND

This study investigated the effects of an aronia juice-based food supplement on background and total DNA strand breaks in whole blood, and on H₂O₂-induced DNA strand breaks in isolated peripheral blood lymphocytes.

METHODS

Ninety-one healthy volunteers were randomly selected to consume either the food supplement (2 × 25 mL drinking ampules, n = 45) or no supplement (n = 46) daily for eight weeks.

RESULTS

Background DNA strand breaks decreased significantly after four and eight weeks of supplement consumption, compared to baseline (p < 0.05), but the overall effect was low, and neither group showed a decrease in total DNA strand breaks. Conversely, supplement consumption clearly reduced H₂O₂-induced DNA strand breaks ex vivo (p < 0.001), with statistically significant reductions after four and eight weeks, compared to the control group (p < 0.05).

CONCLUSIONS

Thus, although consuming antioxidant supplements might produce only marginal immediate benefits under healthy conditions, potential preventive effects warrant further investigation.

Blueberry intervention improves metabolic syndrome risk factors: systematic review and meta-analysis

Recent studies have found that blueberry supplementation can improve parameters related to metabolic syndrome (MetS); however, there is no definitive consensus. Analysis of several randomized controlled trials can demonstrate whether a reduced effect of MetS risk factors is more pronounced in individuals who received supplementation with blueberry than in individuals who did not receive this supplementation. This systematic review and meta-analysis aimed to investigate the effect of blueberry intervention on MetS risk factors, including blood pressure, anthropometric measurements, and glycemic and lipid profiles. PubMed, Scopus, Web of Science, and SciELO were systematically searched to identify relevant studies published before July 2020. To compare the effects of blueberry supplements (powder, extract, fruit, juice, or frozen) with placebo, the mean differences with 95 % confidence intervals (CI) were pooled based on the random-effects model. We classified the quality of evidence according to the GRADE approach. In total, 18 randomized controlled trials (RCTs) were included in this systematic review, and 12 studies were selected for meta-analysis. Based on the Cochrane Collaboration risk-of-bias tool, all studies were of good quality. These trials differed with regards to blueberry dosage and forms, recruited subjects, and trial duration. Meta-analyses of the data showed that blueberry intervention had a significant effect on lipid levels, decreasing total cholesterol and low-density lipoprotein (LDL) levels. We found no significant differences in the glycemic status markers and anthropometric measurements. Blueberry supplementation significantly decreased diastolic blood pressure. In conclusion, the meta-analysis showed that blueberry may be efficacious in the treatment of MetS, due to its beneficial effects on lipid and blood pressure markers.

An 8-week freeze-dried blueberry supplement impacts immune-related pathways: a randomized, double-blind placebo-controlled trial

Background

Blueberries contain high levels of polyphenolic compounds with high in vitro antioxidant capacities. Their consumption has been associated with improved vascular and metabolic health.

Purpose

The objective was to examine the effects of blueberry supplement consumption on metabolic syndrome (MetS) parameters and potential underlying mechanisms of action.

Methods

A randomized double-blind placebo-controlled intervention trial was conducted in adults at risk of developing MetS. Participants consumed 50 g daily of either a freeze-dried highbush blueberry powder (BBP) or a placebo powder for 8 weeks (n = 49). MetS phenotypes were assessed at weeks 0, 4 and 8. Fasting blood gene expression profiles and plasma metabolomic profiles were examined at baseline and week 8 to assess metabolic changes occurring in response to the BBP. A per-protocol analysis was used.

Results

A significant treatment effect was observed for plasma triglyceride levels that was no longer significant after further adjustments for age, sex, BMI and baseline values. In addition, the treatment*time interactions were non-significant therefore suggesting that compared with the placebo, BBP had no statistically significant effect on body weight, blood pressure, fasting plasma lipid, insulin and glucose levels, insulin resistance (or sensitivity) or glycated hemoglobin concentrations. There were significant changes in the expression of 49 genes and in the abundance of 35 metabolites following BBP consumption. Differentially regulated genes were clustered in immune-related pathways.

Conclusion

An 8-week BBP intervention did not significantly improve traditional markers of cardiometabolic health in adults at risk of developing MetS. However, changes in gene expression and metabolite abundance suggest that clinically significant cardiometabolic changes could take longer than 8 weeks to present and/or could result from whole blueberry consumption or a higher dosage. BBP may also have an effect on factors such as immunity even within a shorter 8-week timeframe.

Clinical trial registration

clinicaltrials.gov, NCT03266055, 2017

Supplementary Information

The online version contains supplementary material available at 10.1186/s12263-021-00688-2.

Association between Food Intake, Clinical and Metabolic Markers and DNA Damage in Older Subjects

The use of DNA damage as marker of oxidative stress, metabolic dysfunction and age-related diseases is debated. The present study aimed at assessing the level of DNA damage (evaluated as DNA strand-breaks, endogenous and oxidatively-induced DNA damage) in a group of older subjects with intestinal permeability enrolled within the MaPLE (Gut and Blood Microbiomics for Studying the Effect of a Polyphenol-Rich Dietary Pattern on Intestinal Permeability in the Elderly) intervention trial, to evaluate its association with clinical, metabolic and dietary markers. DNA damage in peripheral blood mononuclear cells was assessed by the comet assay in 49 older subjects participating in the study. Clinical and metabolic markers, markers of inflammation, vascular function and intestinal permeability were determined in serum. Food intake was estimated by weighted food diaries. On the whole, a trend towards higher levels of DNA damage was observed in men compared to women (p = 0.071). A positive association between DNA damage and clinical/metabolic markers (e.g., uric acid, lipid profile) and an inverse association with dietary markers (e.g., vitamin C, E, B₆, folates) were found and differed based on sex. By considering the importance of DNA stability during aging, the results obtained on sex differences and the potential role of dietary and metabolic factors on DNA damage underline the need for further investigations in a larger group of older adults to confirm the associations found and to promote preventive strategies.

Acute Consumption of Blueberries and Short-Term Blueberry Supplementation Improve Glucose Management and Insulin Levels in Sedentary Subjects

BACKGROUND

Blueberries are polyphenol-rich fruits with antioxidant and anti-inflammatory properties. Polyphenols from berries act by blocking digestive enzymes, reshaping gastrointestinal microbiota, and affecting the release of gastrointestinal hormones to regulate insulin dynamics and glucose management. However, most studies use fruit extracts instead of fresh fruit. We aimed to evaluate postprandial glucose management and antioxidant capacity of fresh blueberries consumed acutely or as a six-day supplementation in 10 sedentary subjects.

METHODS

To evaluate the effect of acute blueberry intake, 150 g of blueberries were consumed together with 150 g of white bread by the subject and blood samples were collected at 0, 30, 60, 90 and 120 min to measure glucose, insulin, and plasma antioxidant capacity. To evaluate supplementation, 150 g of blueberries were provided daily for six days and sample collection was performed at day 7.

RESULTS

Acute consumption of blueberries decreased postprandial glucose area under the curve (AUC) and increased insulin levels at 15 min timepoint. Supplementation did not affect glucose levels but decreased insulin levels at 120 min. No changes in antioxidant capacity were observed.

CONCLUSIONS

Consumption of fresh blueberries improves postprandial glucose management presumably due to actions on the gastrointestinal tract, while supplementation improves insulin sensitivity, probably due antioxidant and anti-inflammatory effects.

Berries and Their Polyphenols as a Potential Therapy for Coronary Microvascular Dysfunction: A Mini-Review

Ischemia with no obstructive coronary artery disease (INOCA) is a common diagnosis with a higher prevalence in women compared to men. Despite the absence of obstructive coronary artery disease and no structural heart disease, INOCA is associated with major adverse cardiovascular outcomes as well a significant contributor to angina and related disability. A major feature of INOCA is coronary microvascular dysfunction (CMD), which can be detected by non-invasive imaging and invasive coronary physiology assessments in humans. CMD is associated with epicardial endothelial-dependent and -independent dysfunction, diffuse atherosclerosis, and left-ventricular hypertrophy, all of which lead to insufficient blood flow to the myocardium. Inflammatory and oxidative stress signaling, upregulation of the renin-angiotensin-aldosterone system and adrenergic receptor signaling are major drivers of CMD. Treatment of CMD centers around addressing cardiovascular risk factors; however, there are limited treatment options for those who do not respond to traditional anti-anginal therapies. In this review, we highlight the ability of berry-derived polyphenols to modulate those pathways. The evidence supports the need for future clinical trials to investigate the effectiveness of berries and their polyphenols in the treatment of CMD in INOCA patients.

Blueberry Supplementation in Neuronal Health and Protective Technologies for Efficient Delivery of Blueberry Anthocyanins

Blueberries are consumed as healthy fruits that provide a variety of benefits to the nervous system. Scientists have found that blueberries can be used as a daily edible source for supplementation to prevent and minimize complexities of age-related diseases as well as to improve learning and memory in children. Anthocyanins are the most mentioned compounds among the components in blueberries, as they play a major role in providing the health benefits of this fruit. However, while they are highly active in impeding biological impairment in neuronal functions, they have poor bioavailability. This review focuses on neurological investigations of blueberries from in vitro cell studies to in vivo studies, including animal and human studies, with respect to their positive outcomes of neuroprotection and intervention in neurodegenerative conditions. Readers will also find information on the bioavailability of anthocyanins and the considerable factors affecting them so that they can make informed decisions regarding the daily consumption of blueberries. In this context, the ways in which blueberries or blueberry supplementation forms are consumed and which of these forms is best for maximizing the health benefits of blueberries should be considered important decision-making factors in the consumption of blueberries; all of these aspects are covered in this review. Finally, we discuss recent technologies that have been employed to improve the bioavailability of blueberry anthocyanins in the development of effective delivery vehicles supporting brain health.

A polyphenol-rich dietary pattern improves intestinal permeability, evaluated as serum zonulin levels, in older subjects: The MaPLE randomised controlled trial

BACKGROUND & AIM

Increased intestinal permeability (IP) can occur in older people and contribute to the activation of the immune system and inflammation. Dietary interventions may represent a potential strategy to reduce IP. In this regard, specific food bioactives such as polyphenols have been proposed as potential IP modulator due to their ability to affect several critical targets and pathways that control IP. The trial aimed to test the hypothesis that a polyphenol-rich dietary pattern can decrease serum zonulin levels, an IP surrogate marker involved in tight junction modulation, and can beneficially alter the intestinal microbiota, and IP-associated biochemical and clinical markers in older subjects.

METHODS

A randomised, controlled, cross-over intervention trial was performed. Sixty-six subjects (aged ≥ 60 y) with increased IP based on serum zonulin levels, were randomly allocated to one of the two arms of the intervention consisting of a control diet (C-diet) vs. a polyphenol-rich diet (PR-diet). Each intervention was 8-week long and separated by an 8-week wash out period. At the beginning and at the end of each intervention period, serum samples were collected for the quantification of zonulin and other biological markers. Faecal samples were also collected to investigate the intestinal microbial ecosystem. In addition, anthropometrical/physical/biochemical parameters and food intake were evaluated.

RESULTS

Fifty-one subjects successfully completed the intervention and a high compliance to the dietary protocols was demonstrated. Overall, polyphenol intake significantly increased from a mean of 812 mg/day in the C diet to 1391 mg/day in the PR-diet. Two-way analysis of variance showed a significant effect of treatment (p = 0.008) and treatment × time interaction (p = 0.025) on serum zonulin levels, which decreased after the 8-week PR-diet. In addition, a treatment × time interaction was observed showing a reduction of diastolic blood pressure (p = 0.028) following the PR-diet, which was strongest in those not using antihypertensive drugs. A decrease in both diastolic (p = 0.043) and systolic blood pressure (p = 0.042) was observed in women. Interestingly, a significant increase in fibre-fermenting and butyrate-producing bacteria such as the family Ruminococcaceae and members of the genus Faecalibacterium was observed following the PR intervention. The efficacy of this dietary intervention was greater in subjects with higher serum zonulin at baseline, who showed more pronounced alterations in the markers under study. Furthermore, zonulin reduction was also stronger among subjects with higher body mass index and with insulin resistance at baseline, thus demonstrating the close interplay between IP and metabolic features.

CONCLUSIONS

These data show, for the first time, that a PR-diet can reduce serum zonulin levels, an indirect marker of IP. In addition, PR-diet reduced blood pressure and increased fibre-fermenting and butyrate-producing bacteria. These findings may represent an initial breakthrough for further intervention studies evaluating possible dietary treatments for the management of IP, inflammation and gut function in different target populations. THIS STUDY WAS REGISTERED AT WWW.ISRCTN.

ORG AS

ISRCTN10214981.

Comparative Evaluation of the Effects of Consumption of Colombian Agraz (Vaccinium meridionale Swartz) on Insulin Resistance, Antioxidant Capacity, and Markers of Oxidation and Inflammation, Between Men and Women with Metabolic Syndrome

The metabolic syndrome (MS) is a constellation of related factors that increases the risk of developing cardiovascular diseases. Vaccinium meridionale Swartz contains polyphenols that could modulate some components of MS. Epidemiological and intervention studies have shown differences between men and women in MS components and antioxidant capacity. The objective of this study is to compare between men and women with MS the effects of agraz consumption on insulin resistance, antioxidant capacity, and markers of oxidation and inflammation. Men and women diagnosed with MS according to the Adult Treatment Panel III criteria were recruited in a double-blind, crossover study of 12 weeks. Participants were assigned to consume agraz nectar or placebo over 4 weeks. After 4 weeks of washout, they were switched to the alternative treatment. At the end of each period, the components of the MS, insulin resistance, antioxidant capacity, and some oxidative (oxidized low-density lipoprotein [oxLDL]; thiobarbituric acid reactive substances) and inflammatory (high-sensitive C-reactive protein [hs-CRP]) markers were evaluated. After consuming agraz, there was a tendency to increase the levels of antioxidants and to reduce the levels of hs-CRP in both genders. In addition, women who increased their serum phenols after consuming agraz had a significant reduction in insulin resistance, which was different from the results in men. Regarding men, those who increased their serum antioxidant capacity after consuming agraz had a better effect on the reduction of oxLDL levels that was significant compared to women. There are important differences between genders in the effects of agraz consumption in adults with MS.

Blueberry Consumption Challenges Hepatic Mitochondrial Bioenergetics and Elicits Transcriptomics Reprogramming in Healthy Wistar Rats

An emergent trend of blueberries’ (BB) “prophylactic” consumption, due to their phytochemicals’ richness and well-known health-promoting claims, is widely scaled-up. However, the benefits arising from BB indiscriminate intake remains puzzling based on incongruent preclinical and human data. To provide a more in-depth elucidation and support towards a healthier and safer consumption, we conducted a translation-minded experimental study in healthy Wistar rats that consumed BB in a juice form (25 g/kg body weight (BW)/day; 14 weeks’ protocol). Particular attention was paid to the physiological adaptations succeeding in the gut and liver tissues regarding the acknowledged BB-induced metabolic benefits. Systemically, BB boosted serum antioxidant activity and repressed the circulating levels of 3-hydroxybutyrate (3-HB) ketone bodies and 3-HB/acetoacetate ratio. Moreover, BB elicited increased fecal succinic acid levels without major changes on gut microbiota (GM) composition and gut ultra-structural organization. Remarkably, an accentuated hepatic mitochondrial bioenergetic challenge, ensuing metabolic transcriptomic reprogramming along with a concerted anti-inflammatory pre-conditioning, was clearly detected upon long-term consumption of BB phytochemicals. Altogether, the results disclosed herein portray a quiescent mitochondrial-related metabolomics and hint for a unified adaptive response to this nutritional challenge. The beneficial or noxious consequences arising from this dietary trend should be carefully interpreted and necessarily claims future research.

Effect of dietary anthocyanins on biomarkers of glycemic control and glucose metabolism: A systematic review and meta-analysis of randomized clinical trials

Anthocyanins, as natural food colorants, are bioactive substances with several health advantages. In this research, the effects of dietary anthocyanins on biomarkers of glycemic control and glucose metabolism was evaluated through a meta-analysis. The results revealed a significant reduction in levels of fasting blood sugar (FBS; -2.70 mg/dl, 95% CI: -4.70 to -1.31; P < 0.001), 2-h postprandial glucose (2-h PPG; -11.1 mg/dl, 95% CI: -18.7 to -3.48; P = 0.004), glycated hemoglobin (HbA1c; -11.1 mg/dl, 95% CI: -18.7 to -3.48; P = 0.004), homeostasis model assessment of insulin resistance (HOMA-IR; -0.54, 95% CI: -0.94 to -0.14; P = 0.008), resistin (-1.23 µg/l, 95% CI: -2.40 to -0.05; P = 0.041), and plasminogen activator inhibitor-1 (PAI-1; -5.09 µg/l, 95% CI: -9.45 to -0.73; P = 0.022) following administration of anthocyanins, whilst changes in the levels of fasting insulin (0.33 mU/l, 95% CI: -0.18 to 0.85; P = 0.207) and C-peptide (-0.02 µg/l, 95 %CI: -0.20 to 0.16; P = 0.816) was not statistically significant. Consumption of anthocyanins for >8 weeks and at doses >300 mg/day significantly reduced levels of FBS, 2-h PPG, HbA1c, and HOMA-IR. Moreover, anthocyanins administration reduced the levels of FBS, 2-h PPG, HbA1c, and HOMA-IR in type 2 diabetic subjects and HOMA-IR in overweight/obese individuals. Overall, dietary anthocyanins can be used as an adjuvant therapy to improve biomarkers of glycemic control and glucose metabolism specially in diabetic subjects.

Role of berries in vascular function: a systematic review of human intervention studies

CONTEXT

Berries are a source of polyphenols with recognized health-promoting activities. Several studies suggest that consumption of berries may improve vascular function.

OBJECTIVE

The aim of this systematic review is to provide evidence of short- and long-term benefits of berries on outcomes of vascular function.

DATA SOURCES

Human intervention studies were collected from PubMed and Scopus databases.

STUDY SELECTION

Studies were eligible if they investigated the effects of acute or chronic berry consumption on one or more markers of vascular function in humans and provided a characterization of the berry polyphenolic content. Only randomized controlled trials were included, and studies were excluded if berries were combined with other foods.

DATA EXTRACTION

After selection, 22 randomized controlled trials were included and analyzed, most of which were performed in healthy individuals or patients with cardiovascular risk factors.

RESULTS

The overall results seem to suggest a protective role of berries in vascular function, likely dependent on the time of exposure, the type and dose of berry, and the biomarkers analyzed. Flow-mediated dilation and reactive hyperemia index (markers of vascular reactivity) improved following short-term interventions, while pulse wave velocity and augmentation index (markers of arterial stiffness) improved only after medium- to long-term intervention.

CONCLUSIONS

Current evidence suggests that berries, at physiological relevant doses, may have a role in the modulation of vascular function and stiffness. High-quality human intervention trials are encouraged in order to strengthen these findings and to better elucidate the mechanisms involved in such modulation.

Insights to potential antihypertensive activity of berry fruits

Hypertension is one of the main risk factors for cardiovascular disease and causes widespread morbidity and mortality worldwide. Although several antihypertensive drugs have been proposed for management of high blood pressure, changing lifestyle, including diet, has attracted interest recently. In this sense, consumption of fruits and vegetables, which are rich in vitamins, minerals, and phytochemicals, has been assigned as an efficient therapeutics. Berry fruits contain various bioactive compounds with potential health implications such as antioxidant, antimicrobial, anticancer, and anti-inflammatory properties. The main mechanisms responsible for antihypertensive activity mainly arise from the activity of flavonoids, minerals, and vitamins, as well as fibers. The objective of this review is to provide a summary of studies regarding the effect of berry fruits on the hypertensive animals and humans. The mechanisms involved in reducing blood pressure by each group of compounds have been highlighted. It can be concluded that berries' bioactive compounds are efficient in mitigation of hypertension through improvement of vascular function, angiotensin-converting enzyme's (ACE) inhibitory activity, increasing endothelial nitric oxide synthase (eNOS) activity, and nitric oxide (NO) production, besides anti-oxidative and anti-inflammatory activities. These fruits can be considered as potential sources of invaluable compounds for development of antihypertensive foods and pharmaceuticals.

Potential health benefits of (poly)phenols derived from fruit and 100% fruit juice

(Poly)phenol-rich diets have been associated with reduced risk of various diseases. Coffee and tea are typically identified as dietary sources of chlorogenic acid and flavan-3-ols; however, 100% fruit juice greatly contributes to anthocyanin, flavonol, flavan-3-ols, and flavanone intake, making them complementary sources of dietary (poly)phenols. Thus, the aim of this narrative review was to provide an overview of fruit (poly)phenols and their potential health benefits. Fruit (poly)phenols have been associated with several health benefits (eg, reduced risk of cardiovascular disease and neurocognitive benefits). Although perspectives on 100% fruit juice consumption are controversial due to the perception of sugar content, growing evidence supports the role of fruit in whole and 100% juice forms to provide consumer benefits in alignment with dietary guidance. However, differences in (poly)phenol profiles and bioavailability likely exist between whole fruit and 100% fruit juice due to processing and the presence/absence of fiber. Ongoing studies are better defining similarities and differences between whole fruit and 100% fruit juice to elucidate protective mechanisms and align with processing and consumer products.

Angiogenesis is Differentially Modulated by Anthocyanin and Phenolic Acid Extracts from Wild Blueberry (V. angustifolium) Through PI3K Pathway

Wild blueberries rank very high in anthocyanins (ACNs) and phenolic acids (PA) among other berries. Previous work from our group has documented their beneficial effects. In this study, human umbilical vein endothelial cells were used, and ACNs, PAs, and their combination (ACNs:PAs) at concentrations of 0.002, 8, 15, 60, and 120 μg/mL were tested for endothelial tube formation. Treatment with ACNs decreased, while treatment with PAs and ACNs:PAs increased overall endothelial cell tube formation compared to control. Endothelial cells exposed to ACNs downregulated gene expression of AKT1 and endothelial nitric oxide synthase (eNOS), while PAs upregulated AKT1 and vascular endothelial growth factor (VEGF) gene expression. Combination of ACNs:PAs decreased gene expression of AKT1 and eNOS, while protein levels of AKT1 increased. In summary, based on the type of wild blueberry extract, angiogenesis is differentially modulated and is concentration dependent. Further experiments will delineate the mechanism(s) of the differential action of the aforementioned extracts on angiogenesis.

Effects of chronic consumption of specific fruit (berries, citrus and cherries) on CVD risk factors: a systematic review and meta-analysis of randomised controlled trials

Purpose

This review aims to compare the magnitude of the effects of chronic consumption of fruits; specifically berries, citrus and cherries on cardiovascular disease (CVD) risk factors.

Methods

PubMed, Web of Science, Scopus, and psycARTICLES were searched from inception until January 2020. Forty-five chronic (≥ 1 week) randomised controlled trials assessing CVD risk factors including endothelial (dys)function, blood pressure (BP), blood lipids and inflammatory biomarkers were included.

Results

Investigated interventions reported improvements in endothelial function (n = 8), inflammatory biomarkers and lipid status (n = 14), and BP (n = 10). Berries including juice of barberry, cranberry, grape, pomegranate, powder of blueberry, grape, raspberry and freeze-dried strawberry significantly reduced SBP by 3.68 mmHg (95% CI − 6.79 to − 0.58; P = 0.02) and DBP by 1.52 mmHg (95% CI − 2.87 to − 0.18, P = 0.04). In subgroup analysis, these associations were limited to cranberry juice (SBP by 1.52 mmHg [95% CI − 2.97 to − 0.07; P = 0.05], DBP by 1.78 mmHg [95% CI − 3.43 to − 0.12, P = 0.04] and cherry juice (SBP by 3.11 mmHg [95% CI − 4.06 to − 2.15; P = 0.02]). Berries also significantly elevated sVCAM-1 levels by 14.57 ng/mL (85% CI 4.22 to 24.93; P = 0.02).

Conclusion

These findings suggest that supplementing cranberry or cherry juice might contribute to an improvement in blood pressure. No other significant improvements were observed for other specified fruits. More research is warranted comparing different classes of fruit and exploring the importance of fruit processing on their cardiovascular-protective effects.

Electronic supplementary material

The online version of this article (10.1007/s00394-020-02299-w) contains supplementary material, which is available to authorized users.

Blueberry and cardiovascular disease risk factors: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Cardiovascular disease (CVD) remains an important cause of mortality and morbidity that can be prevented by the consumption of healthy foods. These include blueberry, a dark coloured berry containing extremely high amounts of functional ingredients. We therefore examined the extent to which supplementation with blueberry effects on CVD risk indices.

METHODS

We searched the ISI Web of Science, Scopus, PubMed and Cochrane Library on March 2020 and checked reference lists from primary studies and review articles for any additional studies. No language restrictions were applied. All randomized and controlled clinical trials (RCTs) using blueberry supplements to modify CVD risk factors were included in our analysis.

RESULTS

Mean Difference (MD) was pooled using a random effects model and 11 studies were included in the final analysis. Pooled effect size showed that supplementation with blueberry had a small insignificant effect in reducing plasma triglycerides (MD = -0.27 mmol/l; 95 % CI: -0.57, 0.17, p = 0.06). Although current study found no differences between blueberry and control groups for any other outcomes, subgroup analysis suggested a favourable impact of blueberry on reducing body weight. Significant weight loss was indicated from studies longer with a follow up of more than 6 weeks or with blueberry powder or freeze-dried blueberry.

CONCLUSION

Current evidence is insufficient to show a benefit of blueberry supplements in modifying CVD risk factors across a variety of adult populations. Robust data and larger studies are required to assess potential effects.

Açaí (Euterpe oleracea Mart.) and juçara (Euterpe edulis Mart.) juices improved HDL-c levels and antioxidant defense of healthy adults in a 4-week randomized cross-over study

OBJECTIVE

To evaluate the effects of moderate-term açaí and juçara juice intake on fasting glucose, lipid profile, and oxidative stress biomarkers in healthy subjects.

METHODS

A randomized cross-over study was performed with 30 healthy adults. The subjects were assigned to drink 200 mL/day of açaí or juçara juice for four weeks with a 4-week washout period. Before and after each nutritional intervention, blood samples were obtained to evaluate the outcomes: fasting glucose, total cholesterol, triglycerides, high-density lipoprotein-cholesterol (HDL-c), low-density lipoprotein-cholesterol (LDL-c), small, dense LDL-c (sd-LDL-c), total antioxidant capacity (TAC), total oxidant status (TOS), oxidative stress index (OSI), uric acid, and activity of the enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx).

RESULTS

After four weeks, açaí and juçara juices increased the concentrations of HDL-c by 7.7% and 11.4%, respectively (P < 0.05). In addition, açaí juice intake promoted significant increases in TAC (66.7%), CAT (275.1%), GPx (15.3%), and a decrease in OSI (55.7%) compared to baseline (P < 0.05 for all). Juçara juice intake significantly increased CAT activity (~15.0%) in relation to baseline. No significant intergroup differences were observed for any outcomes (P > 0.05).

CONCLUSION

The results indicated a positive impact of regular consumption of açaí and juçara juices on the HDL-c levels, as well as on the antioxidant enzyme activities, which may contribute to cardiovascular health.

Blueberries and cardiovascular disease prevention

Blueberries are a rich source of (poly)phenols, particularly anthocyanins. Epidemiological studies indicate that anthocyanin-rich foods including blueberries are associated with a reduction in the risk of cardiovascular disease. These observational findings are supported by a number of randomized-controlled trials showing improvements in biomarkers of cardiovascular disease risk. The beneficial effects of blueberry (poly)phenols are particularly clear when measuring flow-mediated dilation over various timeframes and study populations. However, other outcomes are less clear, such as effects on blood pressure, arterial stiffness and blood lipid profile. This may be due to the heterogeneity existing in study designs, such as duration of the intervention, and the health status of participants. Longer-term RCTs using gold standard methods in relevant populations which can be translated to the general public are needed to clarify and strengthen the evidence available. While circulating phenolic blueberry metabolites have been linked with improvements in vascular function, the biological activities and mechanisms of action of individual metabolites and their interaction in vivo are still unknown. Evaluating the bioactivities of metabolites alone and together, and analysing their structure-activity relationship in well-designed and physiologically relevant experimental and human studies are needed to understand the mechanisms of how these metabolites affect vascular function.

Changes in Polyphenolics during Storage of Products Prepared with Freeze-Dried Wild Blueberry Powder

Wild blueberry (WBB) powder can be added to the formulation of foods to encourage consumption of health-promoting polyphenolics, but the stability of polyphenolics throughout storage is important. We determined the stability of polyphenolics in five products (ice pop, oatmeal bar, graham cracker cookie, juice, and gummy product) prepared with WBB powder. Samples stored at 21 °C, 4.4 °C, or −20 °C (ice pops only) were analyzed at 0, 2, 4, 6, and 8 weeks for polyphenolic content and percent polymeric color. Total anthocyanins decreased over storage and storage temperatures in all products. However, the ice pop and the refrigerated juice both retained over 90% of their initial total anthocyanin content. The refrigerated oatmeal bar also showed good retention of anthocyanins (86%), but the gummy product retained only 43% and 51% when stored at 4.4 °C or 21 °C, respectively. The lower amount of polyphenolic compounds recovered in the gummies stored at 4.4 °C compared to 21 °C may be attributed to reduced extraction efficiency as a result of gel hardening at refrigerated temperature. Chlorogenic acid and flavonols were generally more stable than anthocyanins throughout storage.

Fruits

Fruits come in a wide variety of colors, shapes, and flavors. This chapter will cover selected fruits that are known to be healthy and highly nutritious. These fruits were chosen due to their common usage and availability. Since it is not possible to cover all health benefits or essential nutrients and important phytochemicals of the fruit composition, this chapter will focus on the key valuable constituents and their potential health effects.

Impact of dietary anthocyanins on systemic and vascular inflammation: Systematic review and meta-analysis on randomised clinical trials

Anthocyanins are natural bioactive compounds that have several health benefits. This systematic review and meta-analysis assessed the impact of dietary anthocyanins on markers of systemic and vascular inflammation. Meta-analysis of 32 randomised controlled trials indicated that dietary anthocyanins significantly decreased levels of C-reactive protein (CRP; -0.33 mg/l, 95% CI: -0.55 to -0.11, P = 0.003), interleukin-6 (IL-6; -0.41 ρg/ml, 95% CI: -0.70 to -0.13, P = 0.004), tumor necrosis factor-alpha (TNF-α; -0.64 ρg/ml, 95% CI: -1.18 to -0.09, P = 0.023), intercellular adhesion molecule-1 (-52.4 ng/ml, 95% CI: -85.7 to -19.1, P = 0.002), and vascular adhesion molecule-1 (VCAM-1; -49.6 ng/ml, 95% CI: -72.7 to -26.5, P < 0.001) while adiponectin level was significantly increased (0.75 μg/ml, 95% CI: 0.23 to 1.26, P = 0.004). The levels of interleukin-1β (IL-1β; -0.45 ρg/ml, 95% CI: -3.77 to 2.88, P = 0.793) and P-selectin (-6.98 ng/ml, 95% CI: -18.1 to 4.15, P = 0.219) did not significantly change. Subgroup analyses showed that administration of higher doses of anthocyanins (>300 mg/day) significantly decreased levels of CRP, IL-6, TNF-α, and VCAM-1. The results indicate that dietary anthocyanins reduce the levels of systemic and vascular inflammation in the subjects.

Application of the comet assay in human biomonitoring: An hCOMET perspective

The comet assay is a well-accepted biomonitoring tool to examine the effect of dietary, lifestyle, environmental and occupational exposure on levels of DNA damage in human cells. With such a wide range of determinants for DNA damage levels, it becomes challenging to deal with confounding and certain factors are inter-related (e.g. poor nutritional intake may correlate with smoking status). This review describes the effect of intrinsic (i.e. sex, age, tobacco smoking, occupational exposure and obesity) and extrinsic (season, environmental exposures, diet, physical activity and alcohol consumption) factors on the level of DNA damage measured by the standard or enzyme-modified comet assay. Although each factor influences at least one comet assay endpoint, the collective evidence does not indicate single factors have a large impact. Thus, controlling for confounding may be necessary in a biomonitoring study, but none of the factors is strong enough to be regarded a priori as a confounder. Controlling for confounding in the comet assay requires a case-by-case approach. Inter-laboratory variation in levels of DNA damage and to some extent also reproducibility in biomonitoring studies are issues that have haunted the users of the comet assay for years. Procedures to collect specimens, and their storage, are not standardized. Likewise, statistical issues related to both sample-size calculation (before sampling of specimens) and statistical analysis of the results vary between studies. This review gives guidance to statistical analysis of the typically complex exposure, co-variate, and effect relationships in human biomonitoring studies.

Impact of anthocyanin-rich whole fruit consumption on exercise-induced oxidative stress and inflammation: a systematic review and meta-analysis

CONTEXT

Supplementing with fruits high in anthocyanins to reduce exercise-induced oxidative stress and inflammation has produced mixed results.

OBJECTIVE

This systematic review and meta-analysis aims to discuss the impact of whole fruits high in anthocyanins, including processing methods and the type and amount of fruit, on inflammation and oxidative stress.

DATA SOURCES

PICOS reporting guidelines and a customized coding scheme were used to search 5 databases (SPORTDiscus, Science Direct, Web of Science [BIOSIS], Medline [Pubmed], and the Cochrane Collaboration) with additional cross-referencing selection.

DATA EXTRACTION

A random-effects meta-analysis was used to measure effects of the fruit supplements with 3 statistics; the QTotal value based on a χ2 distribution, τ2 value, and I2 value were used to determine homogeneity of variances on 22 studies (out of 807). Outliers were identified using a relative residual value.

RESULTS

A small significant negative summary effect across the sum of all inflammatory marker outcomes (P < 0.001) and a moderate negative effect for the sum of all oxidative stress marker outcomes (P = 0.036) were found. Moderator analyses did not reveal significant (P > 0.05) differences between subgrouping variables.

CONCLUSIONS

Results indicate that consumption of whole fruit high in anthocyanins can be beneficial for reducing inflammation and oxidative stress.

Accumulation of plasma levels of anthocyanins following multiple saskatoon berry supplements

1. Anthocyanins are a subgroup of flavonoids responsible for the blue, purple and red color of many fruits, flowers and leaves. Consumption of foods rich in anthocyanins is associated with a reduced risk of cardiovascular disease and cancer. Most food intervention studies employ once or twice per day dose schedules. 2. The current study demonstrated that plasma concentrations of cyanidin-3-galactoside and cyanidin-3-xyloside, the two major components of saskatoon berries, were significantly increased following three consecutive saskatoon berry supplements 4 hours apart. This accumulation is due to the residual concentrations of anthocyanins at the time of second and third supplements. 3. Accumulation was especially pronounced for peonidin-3-glucoside and peonidin-3-galactoside, the methylated metabolites of cyanidin-3-glucoside and cyanidin-3-galactoside, respectively. Little or no accumulation was observed for cyanidin-3-arabinoside and cyanidin-3-glucoside, two other components of saskatoon berries, possibly due to their short half-lives. 4. Thus, taking anthocyanin supplements with every meal would provide higher plasma concentrations for some anthocyanins and their metabolites than the once or twice-a-day dose regimens.

Bioactive Compounds of Strawberry and Blueberry and Their Potential Health Effects Based on Human Intervention Studies: A Brief Overview

Strawberries and blueberries are two of the most commonly consumed berries. Berries, in general, are characterized by their highly nutritive compounds, including minerals, vitamins, fatty acids, and dietary fiber, as well as their high content and wide diversity of bioactive compounds, such as phenolic compounds and organic acids. These bioactive compounds have been associated with protective effects against chronic diseases, such as cardiovascular disease, cancer, Alzheimer's and other disorders. In this paper 16 human intervention studies investigating the beneficial health effects of dietary strawberry or blueberry consumption on inflammation, cardiovascular disease or cognitive function and mental health are reviewed.

Phenolic and anthocyanin fractions from wild blueberries (V. angustifolium) differentially modulate endothelial cell migration partially through RHOA and RAC1

The present study investigates the effect of anthocyanin (ACN), phenolic acid (PA) fractions, and their combination (ACNs:PAs) from wild blueberry powder (Vaccinum angustifolium) on the speed of endothelial cell migration, gene expression, and protein levels of RAC1 and RHOA associated with acute exposure to different concentrations of ACNs and PAs. Time-lapse videos were analyzed and endothelial cell speed was calculated. Treatment with ACNs at 60 μg/mL inhibited endothelial cell migration rate ( P ≤ 0.05) while treatment with PAs at 0.002 μg/mL ( P ≤ 0.0001), 60 μg/mL ( P ≤ 0.0001), and 120 μg/mL ( P ≤ 0.01) significantly increased endothelial cell migration rate compared with control. Moreover, exposure of HUVECs to ACNs:PAs at 8:8 μg/mL ( P ≤ 0.05) and 60:60 μg/mL increased ( P ≤ 0.001) endothelial cell migration. Gene expression of RAC1 and RHOA significantly increased 2 hours after exposure with all treatments. No effect of the above fractions was observed on the protein levels of RAC1 and RHOA. Findings suggest that endothelial cell migration is differentially modulated based on the type of blueberry extract (ACN or PA fraction) and is concentration-dependent. Future studies should determine the mechanism of the differential action of the above fractions on endothelial cell migration.

Physiological Concentrations of Blueberry-Derived Phenolic Acids Reduce Monocyte Adhesion to Human Endothelial Cells

SCOPE

Blueberry polyphenols are thought to confer cardiovascular health benefits, but have limited bioavailability. They undergo extensive metabolism and their phenolic acid metabolites are likely to be the mediators of bioactivity. The effect of blueberry-derived phenolic acids on one aspect of inflammation, monocyte adhesion to vascular endothelial cells, is investigated.

METHODS AND RESULTS

The major blueberry-derived phenolic acids in human plasma are identified and quantified. Three test mixtures representing compounds present at 0-4 h (Early), 4-24 h (Late), or 0-24 h (Whole) are used to investigate the effect on adhesion of monocytes to tumor necrosis factor alpha (TNFα)-activated endothelial cells. The Late mixture reduces monocyte adhesion, but there is no effect of the Early or Whole mixtures. Exclusion of syringic acid from each mixture results in inhibition of monocyte adhesion. Exposure to the phenolic acid mixtures has no effect on the endothelial surface expression of adhesion molecules intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), or E-selectin, suggesting that other molecular mechanisms are responsible for the observed effect.

CONCLUSION

This study shows that physiological concentrations of blueberry polyphenol metabolites can help maintain cardiovascular health by regulating monocyte adhesion to the vascular endothelium.

Potential Factors Influencing the Effects of Anthocyanins on Blood Pressure Regulation in Humans: A Review

Dietary intake of anthocyanins (ACNs) is associated with a reduced risk of cardiovascular and coronary heart disease. While the anti-inflammatory, antioxidant, and lipid-lowering effects of ACN consumption have been consistently reported, their effect(s) on blood pressure regulation is less consistent and results from human studies are mixed. The objective of this review is attempting to identify potential patterns which may explain the variability in results related to blood pressure. To do so, we review 66 human intervention trials testing the effects on blood pressure of purified ACN or ACN-rich extracts, or whole berries, berry juices, powders, purees and whole phenolic extracts, from berries that are rich in ACN and have ACNs as predominant bioactives. Several factors appear to be involved on the mixed results reported. In particular, the baseline characteristics of the population in terms of blood pressure and total flavonoid intake, the dose and duration of the intervention, the differential effects of individual ACN and their synergistic effects with other phytochemicals, the ACN content and bioavailability from the food matrix, and individual differences in ACN absorption and metabolism related to genotype and microbiota enterotypes.

Blueberries improve biomarkers of cardiometabolic function in participants with metabolic syndrome-results from a 6-month, double-blind, randomized controlled trial

BACKGROUND

Anthocyanin-rich blueberry intake is associated with reduced type 2 diabetes and cardiovascular disease (CVD) risk in prospective studies, although long-term randomized controlled trials (RCTs) have not been conducted in at-risk populations.

OBJECTIVE

In the longest-duration RCT to date, we examined the effect of 6-mo blueberry intake on insulin resistance and cardiometabolic function in metabolic syndrome.

METHODS

A double-blind, parallel RCT (n = 115; age 63 ± 7 y; 68% male; body mass index 31.2 ± 3.0 kg/m2) was conducted, which fed 2 dietarily achievable blueberry intakes [equivalent to 1/2 and 1 cup/d (75/150 g)] compared with matched placebo. Insulin resistance was assessed via the homeostasis model assessment of insulin resistance (primary endpoint) and confirmed by [6-6-2H2]-glucose-labeled, 2-step hyperinsulinemic clamp (n = 20). Clinically relevant cardiometabolic endpoints [including flow-mediated dilatation, augmentation index, lipoprotein status (by nuclear magnetic resonance spectroscopy), and nitric oxide (NO)-related metabolite assay] and anthocyanin metabolism were assessed.

RESULTS

A daily intake of 1 cup of blueberries improved endothelial function (flow-mediated dilatation: +1.45%; 95% CI: 0.83%, 2.1%; P = 0.003), systemic arterial stiffness (augmentation index: -2.24%; 95% CI: -3.97%, -0.61%; P = 0.04) and attenuated cyclic guanosine monophosphate concentrations. In statin nonusers (n = 71), elevated high-density lipoprotein cholesterol (+0.08 mmol/L; P = 0.03), high-density lipoprotein particle density (+0.48n, ×10-6; P = 0.002) and apolipoprotein A-I (+0.05 g/L; P = 0.01) concentrations were observed following the 1-cup/d intervention. Treatment compliance was 94.1% (wrapper returns) and total concentrations of anthocyanin-derived phenolic acid metabolites significantly increased, dose-dependently, in serum and 24-h urine (P < 0.01 and P < 0.001, respectively). Insulin resistance, pulse wave velocity, blood pressure, NO, and overall plasma thiol status were unaffected. Likewise, a half cup per day had no effect on any biomarkers.

CONCLUSIONS

Despite insulin resistance remaining unchanged we show, to our knowledge, the first sustained improvements in vascular function, lipid status, and underlying NO bioactivity following 1 cup blueberries/d. With effect sizes predictive of 12-15% reductions in CVD risk, blueberries should be included in dietary strategies to reduce individual and population CVD risk. This study was registered at clinicaltrials.gov as NCT02035592.

Overview of Human Intervention Studies Evaluating the Impact of the Mediterranean Diet on Markers of DNA Damage

The Mediterranean diet (MD) is characterized by high consumption of fruits, vegetables, cereals, potatoes, poultry, beans, nuts, lean fish, dairy products, small quantities of red meat, moderate alcohol consumption, and olive oil. Most of these foods are rich sources of bioactive compounds which may play a role in the protection of oxidative stress including DNA damage. The present review provides a summary of the evidence deriving from human intervention studies aimed at evaluating the impact of Mediterranean diet on markers of DNA damage, DNA repair, and telomere length. The few results available show a general protective effect of MD alone, or in combination with bioactive-rich foods, on DNA damage. In particular, the studies reported a reduction in the levels of 8-hydroxy-2'⁻deoxyguanosine and a modulation of DNA repair gene expression and telomere length. In conclusion, despite the limited literature available, the results obtained seem to support the beneficial effects of MD dietary pattern in the protection against DNA damage susceptibility. However, further well-controlled interventions are desirable in order to confirm the results obtained and provide evidence-based conclusions.

Sex-Specific Changes in Gut Microbiome Composition following Blueberry Consumption in C57BL/6J Mice

The antioxidant and anti-inflammatory properties of blueberries improve vascular function and insulin sensitivity. However, the bioavailability of the active compounds in blueberries is largely dependent on the gut microbiota, which may themselves be altered by blueberry components. The objective of the current study was to explore a possible sex-dependent modulation of the gut microbiota following supplementation with blueberries in adult mice. Eight-week-old C57BL/6J mice (n = 7⁻10/group) were provided with control or blueberry-containing diets (5% freeze-dried powder) for 4 weeks. Body weight, composition, and food intake were measured weekly. Genomic DNA was isolated from the cecal contents for 16S rRNA sequencing. Blueberry feeding decreased a-diversity (operational taxonomical unit &nbsp;abundance) and altered b-diversity (p < 0.05). At the phylum level, the Firmicutes to Bacteroidetes ratio was significantly lower in the blueberry-fed groups (p < 0.001), along with increased Tenericutes and decreased Deferribacteres. At the genus level, blueberry feeding led to sexually-dimorphic differences, which were associated with predicted metabolic pathways. Pathways such as fatty acid and lipid metabolism were significantly different and demonstrated a stronger association with microbes in the male. To summarize, blueberry supplementation led to sexually-dimorphic global changes in the gut microbiome, which could possibly contribute to physiological changes in mice.

Postprandial Effects of Blueberry (Vaccinium angustifolium) Consumption on Glucose Metabolism, Gastrointestinal Hormone Response, and Perceived Appetite in Healthy Adults: A Randomized, Placebo-Controlled Crossover Trial

The consumption of blueberries, as well as the phenolic compounds they contain, may alter metabolic processes related to type 2 diabetes. The study investigated the effects of adding 140 g of blueberries to a higher-carbohydrate breakfast meal on postprandial glucose metabolism, gastrointestinal hormone response, and perceived appetite. As part of a randomized crossover design study, 17 healthy adults consumed a standardized higher-carbohydrate breakfast along with 2 treatments: (1) 140 g (1 cup) of whole blueberries and (2) a placebo gel (matched for calories, sugars, and fiber of the whole blueberries). Each subject participated in two 2-h meal tests on separate visits ≥8 days apart. Venous blood samples and perceived appetite ratings using visual analog scales were obtained prior to and at 30, 60, 90, and 120 min after consuming the breakfast meals. Results show that glucose metabolism, several gastrointestinal hormones, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), peptide YY (PYY) concentrations and perceived appetite did not change significantly with blueberry consumption. However, pancreatic polypeptide (PP) concentrations were statistically significantly higher (p = 0.0367), and the concentrations were higher during 30, 60, 90, and 120 min after consumption of the blueberry breakfast meal than the placebo breakfast meal. Additional research is needed to determine whether blueberries and other flavonoid-rich foods reduce type 2 diabetes risk by modifying gastrointestinal hormones and perceived appetite.

Blueberry Malvidin-3-galactoside Suppresses Hepatocellular Carcinoma by Regulating Apoptosis, Proliferation, and Metastasis Pathways In Vivo and In Vitro

Anthocyanin, a natural antioxidant, is reported to have cytotoxicity against cancer cells; however, the mechanism remains unclear. The aim of the present study was to investigate the mechanism by which malvidin-3-galactoside (M3G), the prominent anthocyanin in blueberry, suppresses the development of hepatocellular carcinoma. In vitro, M3G suppressed the proliferation, polarization, migration, and invasion activities of HepG2 cells by regulating the protein expression of cyclin D1, cyclin B, cyclin E, caspase-3, cleaved caspase-3, Bax, p-JNK, and p-p38, activating phosphatase and tensin homologue deleted on chromosome 10 (PTEN), accompanied by a decrease in the p-AKT level, and lowering the protein expression levels of MMP-2 and MMP-9. In vivo, M3G promoted the apoptosis of liver tumor cells, as determined by immunohistochemistry (cleaved caspase-3, Ki-67, PTEN, and p-AKT), a terminal deoxynucleotidyl transferase dUTP nick end labeling assay, and hematoxylin-eosin staining. Overall, these results suggest that M3G, as an adjuvant ingredient or nutritional supplement, may be beneficial for liver cancer prevention and the modulatory mechanism seems to be associated with inhibition of proliferation, apoptosis, migration, and invasion-related pathways.

Changing to a Low-Polyphenol Diet Alters Vascular Biomarkers in Healthy Men after Only Two Weeks

Bioactive dietary compounds play a critical role in health maintenance. The relation between bioactive compound intake and cardiovascular health-related biomarkers has been demonstrated in several studies, although mainly with participants who have altered biochemical parameters (high blood pressure, high cholesterol, metabolic syndrome, etc.). The aim of this study was to evaluate if adopting a diet low in polyphenol-rich food for two weeks would affect vascular biomarkers in healthy men. In a crossover study, 22 healthy men were randomly assigned to their usual diet (UD), consuming healthy food rich in polyphenols, or to a low antioxidant diet (LAD), with less than two servings of fruit and vegetables per day and avoiding the intake of cocoa products, coffee and tea. As a marker of compliance, total polyphenols in urine were significantly lower after the LAD than after the UD (79 ± 43 vs. 123 ± 58 mg GAE/g creatinine). Nitric oxide levels were also reduced (52 ± 28 in LAD vs. 80 ± 34 µM in UD), although no significant changes in cellular adhesion molecules and eicosanoids were observed; however, an increasing ratio between thromboxane A₂ (TXA₂) and prostaglandin I₂ (PGI₂) was reached (p = 0.048). Thus, a slight dietary modification, reducing the consumption of polyphenol-rich food, may affect vascular biomarkers even in healthy individuals.

Are Raw Brassica Vegetables Healthier Than Cooked Ones? A Randomized, Controlled Crossover Intervention Trial on the Health-Promoting Potential of Ethiopian Kale

The present human intervention trial investigated the health-promoting potential of B. carinata, with a focus on effects of thermal processing on bioactivity. Twenty-two healthy subjects consumed a B. carinata preparation from raw (allyl isothiocyanate-containing) or cooked (no allyl isothiocyanate) leaves for five days in a randomized crossover design. Peripheral blood mononuclear cells were exposed to aflatoxin B1 (AFB1), with or without metabolic activation using human S9 mix, and subsequently analyzed for DNA damage using the comet assay. Plasma was analyzed for total antioxidant capacity and prostaglandin E₂ (PGE₂) levels. Cooked B. carinata significantly reduced DNA damage induced by AFB1 as compared to baseline levels (+S9 mix: 35%, -S9 mix: 33%, p ≤ 0.01, respectively). Raw B. carinata only reduced DNA damage by S9-activated AFB1 by 21% (p = 0.08). PGE₂ plasma levels were significantly reduced in subjects after consuming raw B. carinata. No changes in plasma antioxidant capacity were detectable. A balanced diet, including raw and cooked Brassica vegetables, might be suited to fully exploit the health-promoting potential. These results also advocate the promotion of B. carinata cultivation in Eastern Africa as a measure to combat effects of unavoidable aflatoxin exposure.

Evaluation of Agraz Consumption on Adipocytokines, Inflammation, and Oxidative Stress Markers in Women with Metabolic Syndrome

Metabolic syndrome (MetS) is characterized by increased oxidative stress and a pro-inflammatory state. Vaccinium meridionale Swartz (known as “agraz”) is a berry rich in polyphenolic compounds with demonstrated antioxidant activity and anti-inflammatory effects in preclinical studies. The aim of this study was to evaluate the effects of agraz consumption on inflammatory and oxidative stress markers in women with MetS. Forty women with MetS (47 ± 9 years) were randomly assigned to consume daily either 200 mL of agraz nectar or placebo over four weeks in a double-blind, cross-over design study, separated by a 4-week washout period. Metabolic and inflammatory markers in serum and antioxidant/oxidative stress markers in serum and urine were assessed at the end of each period. Serum antioxidant capacity measured by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method was significantly higher (p = 0.028), while urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) was lower (p = 0.041) after agraz consumption, compared to placebo. In conclusion, consumption of agraz during four weeks increased serum antioxidant capacity and decreased a marker of DNA oxidative damage in women with MetS, compared to placebo. These results suggest that agraz consumption may play a protective role in patients with MetS.

Health promoting properties of blueberries: a review

With the strengthening of the link between diet and health, several foodstuffs have emerged as possessing potential health benefits such as phenolic rich fruits and vegetables. Blueberries, along with other berries, given their flavonoid and antioxidant content have long since been considered as a particularly interesting health promoting fruit. Therefore, the present work aimed to compile the existing evidences regarding the various potential benefits of blueberry and blueberry based products consumption, giving particular relevance to in vivo works and epidemiological studies whenever available. Overall, the results demonstrate that, while the evidences that support a beneficial role of blueberry and blueberry extracts consumption, further human based studies are still needed.

Effects of superfoods on risk factors of metabolic syndrome: a systematic review of human intervention trials

Functional foods can be effective in the prevention of metabolic syndrome and subsequently the onset of cardiovascular diseases and type II diabetes mellitus. More recently, however, another term was introduced to describe foods with additional health benefits: "superfoods", for which, to date, no generally accepted definition exists. Nonetheless, their consumption might contribute to the prevention of metabolic syndrome, for example due to the presence of potentially bioactive compounds. This review provides an overview of controlled human intervention studies with foods described as "superfoods" and their effects on metabolic syndrome parameters. First, an Internet search was performed to identify foods described as superfoods. For these superfoods, controlled human intervention trials were identified until April 2017 investigating the effects of superfood consumption on metabolic syndrome parameters: waist circumference or BMI, blood pressure, or concentrations of HDL cholesterol, triacylglycerol or glucose. Seventeen superfoods were identified, including a total of 113 intervention trials: blueberries (8 studies), cranberries (8), goji berries (3), strawberries (7), chili peppers (3), garlic (21), ginger (10), chia seed (5), flaxseed (22), quinoa (1), cocoa (16), maca (1), spirulina (7), wheatgrass (1), acai berries (0), hemp seed (0) and bee pollen (0). Overall, only limited evidence was found for the effects of the foods described as superfoods on metabolic syndrome parameters, since results were not consistent or the number of controlled intervention trials was limited. The inconsistencies might have been related to intervention-related factors, such as duration or dose. Furthermore, conclusions may be different if other health benefits are considered.

Prevention of Atherosclerosis by Berries: The Case of Blueberries

Berry consumption has been associated with cardiovascular disease prevention in recent years. Atherosclerosis is one of the major causes of cardiovascular diseases. However, research on the prevention of atherosclerosis through consuming individual whole berries, specifically direct evidence, remains scarce. Therefore, further elucidating the role that berries play in the prevention of atherosclerosis is warranted. In this perspective, blueberries were selected to articulate research strategies for studying atheroprotective effects of berries. Studies from human subjects and various animal models are summarized. The mechanisms by which blueberries may act, through reducing oxidative stress, decreasing inflammation, improving endothelial dysfunction, regulating cholesterol accumulation and trafficking, along with potentially influencing gut microbiota, are also discussed. Blueberries contain high levels of polyphenolic compounds, which were widely indicated as major bioactive compounds. Nonetheless, the metabolites/catabolites after blueberry consumption, such as simple phenolic acids, rather than original compounds in berries, may be the actual in vivo bioactive compounds. Future research should focus on obtaining more direct evidence, preferably in humans, understanding of the mechanisms of action at the molecular level, and identifying bioactive compounds as well as which compounds act synergistically to convey health benefits. The research strategy discussed here may also be applied to the studies of other fruits and berries.