The effect of increased dietary fruit and vegetable consumption on endothelial activation, inflammation and oxidative stress in hypertensive volunteers

Adherence to the Mediterranean Diet Association with Serum Levels of Nitric Oxide, Prostacyclin, and Thromboxane B2 among Prinzmetal Angina Patients and Healthy Persons

This study aimed to assess the association between adherence to the Mediterranean diet with serum Nitric oxide, Prostacyclin, and Thromboxane B₂ among Prinzmetal angina patients and healthy persons. This case-control study was conducted among 100 Prinzmetal angina patients and 100 healthy persons referred to the Ardabil Imam Khomeini hospital between 2021 and 2022. Blood samples were obtained from all study participants for measurement of serum Nitric oxide, Prostacyclin, and Thromboxane B₂. To calculate adherence to the Mediterranean diet, the ten-item screener was used. The serum Nitric oxide in patients who adhered more to the Mediterranean diet was higher than patients with less adherence (coeff. = 0.41 p = 0.04). The serum Prostacyclin level in patients with greater adherence to the Mediterranean diet was 0.34 units higher than patients with less adherence (coeff. = 0.34 p = 0.02). The level of serum Thromboxane B₂ had a negative association with adherence to the Mediterranean diet (coeff. = -0.48 p = 0.04). The amount of consumption of olive oil, fruits, vegetables, and legumes in healthy people was more than Prinzmetal angina patients. In Prinzmetal angina patients, more adherence to the Mediterranean diet can decrease the serum Thromboxane B₂ and increase the serum Nitric oxide and Prostacyclin.

Meeting report: plant-rich dietary patterns and health

Dietary patterns (DP) rich in plant foods are associated with improved health and reduced non-communicable disease risk. In October 2021, the Nutrition Society hosted a member-led conference, held online over 2 half days, exploring the latest research findings examining plant-rich DP and health. The aim of the present paper is to summarise the content of the conference and synopses of the individual speaker presentations are included. Topics included epidemiological analysis of plant-rich DP and health outcomes, the effects of dietary interventions which have increased fruit and vegetable (FV) intake on a range of health outcomes, how adherence to plant-rich DP is assessed, the use of biomarkers to assess FV intake and a consideration of how modifying behaviour towards increased FV intake could impact environmental outcomes, planetary health and food systems. In conclusion, although there are still considerable uncertainties which require further research, which were considered as part of the conference and are summarised in this review, adopting a plant-rich DP at a population level could have a considerable impact on diet and health outcomes, as well as planetary health.

Consumption of Vegetables Is Associated with Systemic Inflammation in Older Adults

It is hypothesized that healthy diets rich in fruits and vegetables (FV) can modulate the inflammatory status in older adults. However, to determine the actual impact of FV on inflammatory status, adiposity level and objectively assessed physical activity (PA) behaviors need to be considered. The aim of the present study was to explore associations between FV intake and biomarkers of systemic inflammation in older adults. Based on a sample of 233 older adults (65−70 years old), the following inflammatory biomarkers were assessed: C-reactive protein (CRP), fibrinogen, interleukin-6 (IL-6), IL-10, IL-18, and monocyte chemoattractant protein-1 (MCP-1). FV intake was assessed by self-report, and PA behaviors encompassing time spent sedentary and in moderate-to-vigorous PA (MVPA) were determined using accelerometers. Associations between FV intake and inflammatory biomarkers were analyzed using stepwise linear regression models while adjusting for several covariates, including health-related food groups, adherence to the MVPA guidelines, total sedentary time, and waist circumference. While no significant associations were observed for the total FV intake, the vegetable intake was inversely associated with levels of IL6 (β = −0.15; p < 0.05). In contrast, fruit intake was not associated with any inflammatory biomarker. In conclusion, our findings indicate beneficial associations between vegetable intake and levels of a pro-inflammatory biomarker in older adults, which strengthens public health efforts to promote vegetable-rich diets in older adults to mitigate age-related systemic inflammation.

Randomized Controlled Trial for Promotion of Healthy Eating in Older Adults by Increasing Consumption of Plant-Based Foods: Effect on Inflammatory Biomarkers

To what extent the intake of fruit and vegetables (FV) influences inflammatory status remains elusive, particularly in older populations. The aim of the present study was to determine the effect of increased FV intake for 16 weeks on circulating biomarkers of inflammation in a population of older men and women. Sixty-six participants (65-70 years) randomly assigned to either FV or control (CON) groups were instructed to increase FV intake to five servings per day through nutritional counseling (FV) or to maintain habitual diet (CON). Dietary intake and physical activity level (PA) were determined using food frequency questionnaire and accelerometers, respectively, at the start and end of the intervention. C-reactive protein (CRP), interleukin 6 (IL-6), IL-18, macrophage inflammatory protein-1α (MIP-1α), MIP-1β, tumor necrosis factor-α (TNF-α), TNF-related apoptosis-inducing ligand (TRAIL), TNF-related activation-induced cytokine (TRANCE), and C-X3-C motif chemokine ligand-1 (CX3CL1, or fractalkine) were analyzed. The FV group significantly increased daily FV intake (from 2.2 ± 1.3 to 4.2 ± 1.8 servings/day), with no change in CON. Waist circumference and PA level were unchanged by the intervention. Interaction effects (time × group, p < 0.05) for TRAIL, TRANCE, and CX3CL1 denoting a significant decrease (p < 0.05) in FV but not in CON were observed. No corresponding effects on CRP, IL6, TNF-α, MIP-1α, and β and IL-18 were observed. The present study demonstrates the influence of increased FV consumption on levels of some inflammatory biomarkers in a population of older adults. Future work is warranted to examine the clinical implications of FV-induced alterations in these inflammatory biomarkers.

Non-pharmacological management of hypertension

Hypertension is an insidious disease which predisposes to cardiovascular complications and if not treated properly can lead to various serious complications. Economic limitations, having additional benefits with few or almost no side effects have made non-pharmacological management of hypertension an attractive approach for dealing with hypertension, in developed and developing countries alike. A MEDLINE search was done for relevant references with emphasis on original studies, randomized controlled trials, and meta-analyses for this review paper. Lifestyle modifications including changes in the dietary pattern, adopting special diets with low sodium, saturated fat and high calcium, magnesium and potassium and trying the new methods like time restricted meal intake which work in tandem with the circadian rhythm are opening new vistas in the field of non-pharmacological management of hypertension. Lifestyle modifications that effectively lower blood pressure are increased physical activity, weight loss, limited alcohol consumption, relaxation techniques of Yoga, Acupuncture, Tai chi, mindfulness-based stress-reduction program, and Transcendental Meditation. Air pollution of the surrounding air is linked with poor health outcomes and is a major contributor to the global burden of disease. Fine particulate matter <2.5 μm in diameter (PM2.5) is strongly associated with cardiovascular morbidity and mortality. Short-term PM exposure (hours to weeks) increases the likelihood of adverse cardiovascular events including myocardial infarction, stroke, and heart failure, and longer-term exposure multiplies that risk. Non-pharmacological methods should be initiated early phase of disease and should be continued with medication.

Natural Products in the Prevention of Metabolic Diseases: Lessons Learned from the 20th KAST Frontier Scientists Workshop

The incidence of metabolic and chronic diseases including cancer, obesity, inflammation-related diseases sharply increased in the 21st century. Major underlying causes for these diseases are inflammation and oxidative stress. Accordingly, natural products and their bioactive components are obvious therapeutic agents for these diseases, given their antioxidant and anti-inflammatory properties. Research in this area has been significantly expanded to include chemical identification of these compounds using advanced analytical techniques, determining their mechanism of action, food fortification and supplement development, and enhancing their bioavailability and bioactivity using nanotechnology. These timely topics were discussed at the 20th Frontier Scientists Workshop sponsored by the Korean Academy of Science and Technology, held at the University of Hawaii at Manoa on 23 November 2019. Scientists from South Korea and the U.S. shared their recent research under the overarching theme of Bioactive Compounds, Nanoparticles, and Disease Prevention. This review summarizes presentations at the workshop to provide current knowledge of the role of natural products in the prevention and treatment of metabolic diseases.

Dietary habits, lipoprotein metabolism and cardiovascular disease: From individual foods to dietary patterns

Cardiovascular disease (CVD) remains the first cause of mortality in Western countries. Among cardiometabolic risk factors, dyslipidemia, and especially high low-density lipoprotein cholesterol (LDL-C) concentrations, have been extensively linked to the development and progression of atherosclerosis and to CVD events. Recent evidence has shown that the prevention of unhealthy dietary habits and sedentarism is crucial in the management of dyslipidemia. In this sense, a number of scientific societies recommend the adherence to certain healthy dietary patterns (DPs), such as the Mediterranean diet (MedDiet), the Dietary Approaches to Stop Hypertension (DASH), the Portfolio diet, the Vegetarian diet, the Nordic diet and low-carbohydrate diets, as well as increased physical activity between others. This nutritional and lifestyle advice could be adopted by government bodies and implemented in different health programs as a reliable way of providing health-care professionals with efficient tools to manage cardiometabolic risk factors and thus, prevent CVD. In this narrative review, we will discuss recent data about the effects of nutrition on dyslipidemia, mainly focusing on high LDL-C concentrations and other lipid particles related to atherogenic dyslipidemia such as triglycerides (TG) and non-high density lipoprotein cholesterol (non-HDL-C), that are related to CVD. On the other hand, we also comment on other cardiometabolic risk factors such as type 2 diabetes mellitus (T2DM), high blood pressure (HBP), inflammation and endothelial dysfunction. This review includes food groups as well as different healthy DPs.

A diet high in sugar-sweetened beverage and low in fruits and vegetables is associated with adiposity and a pro-inflammatory adipokine profile

Diet, obesity and adipokines play important roles in diabetes and CVD; yet, limited studies have assessed the relationship between diet and multiple adipokines. This cross-sectional study assessed associations between diet, adiposity and adipokines in Mexican Americans. The cohort included 1128 participants (age 34·7±8·2 years, BMI 29·5±5·9 kg/m2, 73·2 % female). Dietary intake was assessed by 12-month food frequency questionnaire. Adiposity was measured by BMI, total percentage body fat and percentage trunk fat using dual-energy X-ray absorptiometry. Adiponectin, apelin, C-reactive protein (CRP), dipeptidyl peptidase-4 (DPP-IV), IL-1β, IL-1ra, IL-6, IL-18, leptin, lipocalin, monocyte chemo-attractant protein-1 (MCP-1), resistin, secreted frizzled protein 4 (SFRP-4), SFRP-5, TNF-α and visfatin were assayed with multiplex kits or ELISA. Joint multivariate associations between diet, adiposity and adipokines were analysed using canonical correlations adjusted for age, sex, energy intake and kinship. The median (interquartile range) energy intake was 9514 (7314, 11912) kJ/d. Overall, 55 % of total intake was accounted for by carbohydrates (24 % from sugar). A total of 66 % of the shared variation between diet and adiposity, and 34 % of diet and adipokines were explained by the top canonical correlation. The diet component was most represented by sugar-sweetened beverages (SSB), fruit and vegetables. Participants consuming a diet high in SSB and low in fruits and vegetables had higher adiposity, CRP, leptin, and MCP-1, but lower SFRP-5 than participants with high fruit and vegetable and low SSB intake. In Mexican Americans, diets high in SSB but low in fruits and vegetables contribute to adiposity and a pro-inflammatory adipokine profile.

Effects of High Consumption of Vegetables on Clinical, Immunological, and Antioxidant Markers in Subjects at Risk of Cardiovascular Diseases

High intakes of vegetables have been associated with a lower incidence of cardiovascular diseases (CVD). However, the effect of vegetables on immune function and antioxidant status in human studies have provided contrasting results. In the present study, after a week of run-in period, 38 subjects at risk of CVD were randomly assigned to one of the following 4-week interventions: low vegetable consumption (800 g of vegetables/week) or high vegetable consumption (4200 g of vegetables/week). Vegetables included carrots, topinambur (Jerusalem artichoke, Helianthus tuberosus), tomatoes, red cabbage, and sweet peppers. Blood and salivary samples were collected before and after intervention periods. In addition to clinical, immunological, and antioxidant markers, leukocyte and lymphocyte expression of the gut-homing β7 integrin was evaluated. No significant changes were detected in clinical, immunological, and antioxidant markers in biological samples, except for an increase in white blood cell count for the low vegetable consumption group (p < 0.05). The study provides additional evidence about the uncertainty of providing a clear evidence for vegetables in modulating markers of immune function and antioxidant status. Further studies are needed in order to unravel the mechanism of effect of vegetable consumption in cardiovascular prevention.

Role of whole grains versus fruits and vegetables in reducing subclinical inflammation and promoting gastrointestinal health in individuals affected by overweight and obesity: a randomized controlled trial

BACKGROUND

Whole grains (WG) and fruits and vegetables (FV) have been shown to reduce the risk of metabolic disease, possibly via modulation of the gut microbiota. The purpose of this study was to determine the impact of increasing intake of either WG or FV on inflammatory markers and gut microbiota composition.

METHODS

A randomized parallel arm feeding trial was completed on forty-nine subjects with overweight or obesity and low intakes of FV and WG. Individuals were randomized into three groups (3 servings/d provided): WG, FV, and a control (refined grains). Stool and blood samples were collected at the beginning of the study and after 6 weeks. Inflammatory markers [tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), lipopolysaccharide binding protein (LBP), and high sensitivity C-reactive protein (hs-CRP)] were measured. Stool sample analysis included short/branched chain fatty acids (S/BCFA) and microbiota composition.

RESULTS

There was a significant decrease in LBP for participants on the WG (- 0.2 μg/mL, p = 0.02) and FV (- 0.2 μg/mL, p = 0.005) diets, with no change in those on the control diet (0.1 μg/mL, p = 0.08). The FV diet induced a significant change in IL-6 (- 1.5 pg/mL, p = 0.006), but no significant change was observed for the other treatments (control, - 0.009 pg/mL, p = 0.99; WG, - 0.29, p = 0.68). The WG diet resulted in a significant decrease in TNF-α (- 3.7 pg/mL; p < 0.001), whereas no significant effects were found for those on the other diets (control, - 0.6 pg/mL, p = 0.6; FV, - 1.4 pg/mL, p = 0.2). The treatments induced individualized changes in microbiota composition such that treatment group differences were not identified, except for a significant increase in α-diversity in the FV group. The proportions of Clostridiales (Firmicutes phylum) at baseline were correlated with the magnitude of change in LBP during the study.

CONCLUSIONS

These data demonstrate that WG and FV intake can have positive effects on metabolic health; however, different markers of inflammation were reduced on each diet suggesting that the anti-inflammatory effects were facilitated via different mechanisms. The anti-inflammatory effects were not related to changes in gut microbiota composition during the intervention, but were correlated with microbiota composition at baseline.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT02602496 , Nov 4, 2017.

Effects of fruit and vegetable consumption on inflammatory biomarkers and immune cell populations: a systematic literature review and meta-analysis

BACKGROUND

Inflammation is associated with an increased risk of a range of chronic diseases. A diet high in fruit and vegetables may help to reduce inflammation, as fruit and vegetables are rich sources of antioxidants and other biologically active substances, which may improve immune function.

OBJECTIVE

To summarize the evidence, we executed a systematic review and meta-analysis examining the effects of fruit and/or vegetable intake on inflammatory biomarkers and immune cells in humans with different diseases and conditions.

Design

Electronic databases including PubMed, Cochrane, CINAHL, and EMBASE were systematically searched up to March 2018.

RESULTS

Eighty-three studies were included. Of these, 71 (86%) were clinical trials, and 12 were observational studies (n = 10 cross-sectional and n = 2 cohort). Amongst the observational research, n = 10 studies found an inverse association between intakes of fruit or vegetables and inflammatory biomarkers. Similarly, the majority of the intervention studies (68%, n = 48) reported beneficial effects of fruit or vegetable intake on ≥1 biomarker of systemic or airway inflammation. A meta-analysis of included studies showed that fruit or vegetable intake decreased circulating levels of C-reactive protein and tumor necrosis factor-α (P < 0.05) and increased the γδ-T cell population (P < 0.05).

Conclusions

In conclusion, this review suggests that higher intakes of fruit and vegetables lead to both a reduction in proinflammatory mediators and an enhanced immune cell profile.

Lifestyle recommendations for the prevention and management of metabolic syndrome: an international panel recommendation

The importance of metabolic syndrome (MetS) lies in its associated risk of cardiovascular disease and type 2 diabetes, as well as other harmful conditions such as nonalcoholic fatty liver disease. In this report, the available scientific evidence on the associations between lifestyle changes and MetS and its components is reviewed to derive recommendations for MetS prevention and management. Weight loss through an energy-restricted diet together with increased energy expenditure through physical activity contribute to the prevention and treatment of MetS. A Mediterranean-type diet, with or without energy restriction, is an effective treatment component. This dietary pattern should be built upon an increased intake of unsaturated fat, primarily from olive oil, and emphasize the consumption of legumes, cereals (whole grains), fruits, vegetables, nuts, fish, and low-fat dairy products, as well as moderate consumption of alcohol. Other dietary patterns (Dietary Approaches to Stop Hypertension, new Nordic, and vegetarian diets) have also been proposed as alternatives for preventing MetS. Quitting smoking and reducing intake of sugar-sweetened beverages and meat and meat products are mandatory. Nevertheless, there are inconsistencies and gaps in the evidence, and additional research is needed to define the most appropriate therapies for MetS. In conclusion, a healthy lifestyle is critical to prevent or delay the onset of MetS in susceptible individuals and to prevent cardiovascular disease and type 2 diabetes in those with existing MetS. The recommendations provided in this article should help patients and clinicians understand and implement the most effective approaches for lifestyle change to prevent MetS and improve cardiometabolic health.

A Mediterranean diet lowers blood pressure and improves endothelial function: results from the MedLey randomized intervention trial

Background: The consumption of a Mediterranean diet (MedDiet) is associated with a lower risk of cardiovascular disease. However, its impact on blood pressure and endothelial function is not clear.Objective: We sought to determine the effects of adhering to the consumption of a MedDiet for 6 mo on blood pressure and endothelial function in older, healthy Australians.Design: A total of 166 men and women aged >64 y were allocated via minimization to consume either a MedDiet (n = 85) or their habitual diet (HabDiet; control: n = 81) for 6 mo. The MedDiet comprised mainly plant foods, abundant extra-virgin olive oil, and minimal red meat and processed foods. A total of 152 participants commenced the study, and 137 subjects completed the study. Home blood pressure was measured on 5 consecutive days at baseline (n = 149) and at 3 and 6 mo. Endothelial function (n = 82) was assessed by flow-meditated dilatation (FMD) at baseline and 6 mo. Dietary intake was monitored with the use of 3-d weighed food records. Data were analyzed with the use of linear mixed-effects models to determine adjusted between-group differences.Results: The MedDiet adherence score increased significantly in the MedDiet group but not in the HabDiet group (P < 0.001). The MedDiet, compared with the HabDiet, resulted in lower systolic blood pressure (P-diet × time interaction = 0.02) [mean: -1.3 mm Hg (95% CI: -2.2, -0.3 mm Hg; P = 0.008) at 3 mo and -1.1 mm Hg (95% CI: -2.0, -0.1 mm Hg; P = 0.03) at 6 mo]. At 6 mo, the percentage of FMD was higher by 1.3% (95% CI: 0.2%, 2.4%; P = 0.026) in the MedDiet group.Conclusion: Australian men and women who consumed a MedDiet for 6 mo had small but significantly lower systolic blood pressure and improved endothelial function. This trial was registered at www.anzctr.org.au as ACTRN12613000602729.

Effects of Montmorency tart cherry (Prunus Cerasus L.) consumption on vascular function in men with early hypertension

BACKGROUND

Tart cherries contain numerous polyphenolic compounds that could potentially improve endothelial function and reduce cardiovascular disease risk.

OBJECTIVE

We sought to examine the acute effects of Montmorency tart cherry (MC) juice on vascular function in subjects with early hypertension.

DESIGN

A placebo-controlled, blinded, crossover, randomized Latin square design study with a washout period of ≥14 d was conducted. Fifteen men with early hypertension [systolic blood pressure (SBP) ≥130 mm Hg, diastolic blood pressure ≥80 mm Hg, or both] received either a 60-mL dose of MC concentrate or placebo. Microvascular reactivity (laser Doppler imaging with iontophoresis), arterial stiffness (pulse wave velocity and analysis), blood pressure, and phenolic acid absorption were assessed at baseline and at 1, 2, 3, 5, and 8 h postconsumption.

RESULTS

MC consumption significantly lowered SBP (P < 0.05) over a period of 3 h, with peak reductions of mean ± SEM 7 ± 3 mm Hg 2 h after MC consumption relative to the placebo. Improvements in cardiovascular disease risk factors were closely linked to increases in circulating protocatechuic and vanillic acid at 1-2 h.

CONCLUSIONS

MC intake acutely reduces SBP in men with early hypertension. These benefits may be mechanistically linked to the actions of circulating phenolic acids. This study provides information on a new application of MCs in health maintenance, particularly in positively modulating SBP. This trial was registered at clinicaltrials.gov as NCT02234648.

Increasing Fruit and Vegetable Intake Has No Dose-Response Effect on Conventional Cardiovascular Risk Factors in Overweight Adults at High Risk of Developing Cardiovascular Disease

BACKGROUND

Improving diet and lifestyle is important for prevention of cardiovascular disease (CVD). Observational evidence suggests that increasing fruit and vegetable (FV) consumption may lower CVD risk, largely through modulation of established risk factors, but intervention data are required to fully elucidate the mechanisms by which FVs exert benefits on vascular health.

OBJECTIVE

The aim of this study was to examine the dose-response effect of FV intake on cardiovascular risk factors in adults at high CVD risk.

METHODS

This was a randomized controlled parallel group study involving overweight adults (BMI: >27 and ≤35 kg/m(2)) with a habitually low FV intake (≤160 g/d) and a high total risk of developing CVD (estimated ≥20% over 10 y). After a 4-wk run-in period where FV intake was limited to <2 portions/d (<160 g/d), 92 eligible participants were randomly assigned to 1 of 3 groups: to consume either 2, 4, or 7 portions (equivalent to 160 g, 320 g, or 560 g, respectively) of FVs daily for 12 consecutive weeks. Fasting venous blood samples were collected at baseline (week 4) and post-intervention (week 16) for analysis of lipid fractions and high-sensitivity C-reactive protein (hsCRP) concentrations. Compliance with the FV intervention was determined with use of self-reported FV intake and biomarkers of micronutrient status. Ambulatory blood pressure and body composition were also measured pre- and post-intervention.

RESULTS

A total of 89 participants completed the study and body composition remained stable throughout the intervention period. Despite good compliance with the intervention, no significant difference was found between the FV groups for change in measures of ambulatory blood pressure, plasma lipids, or hsCRP concentrations.

CONCLUSIONS

There was no evidence of a dose-response effect of FV intake on conventional CVD risk factors measured in overweight adults at high CVD risk. This trial was registered at clinicaltrials.gov as NCT00874341.

Fruit and vegetable intake and urinary levels of prostaglandin E₂ metabolite in postmenopausal women

Prostaglandin E2 (PGE2) is an inflammatory mediator that plays key roles in promoting tumor development and progression. Urinary concentration of a major PGE2 metabolite (PGE-M) has been recently proposed as a promising cancer biomarker. Using dietary intake data from 600 postmenopausal women aged 50-74 years, we examined cross-sectional relationships between fruit and vegetable intake and urinary levels of PGE-M, determined using liquid chromatography/tandem mass spectrometry. After multivariable adjustment, increasing consumption of fruits, but not vegetables, was associated with reduced levels of urinary PGE-M (P for linear trend = 0.02), with geometric means of 5.8 [95% confidence interval (CI): 5.2-6.6] in the lowest quintile versus 4.8 (95% CI: 4.3-5.4) in the highest quintile (Q5) of fruit consumption. A better quality diet, indicated by higher scores on the Healthy Eating Index, was also associated with decreased PGE-M (P for linear trend <0.01). The lack of association with vegetable intake may be related to variation in antioxidant capacities of the major dietary sources of fruits and vegetables for the study participants. Our findings suggest that urinary PGE-M may be modifiable by a healthy diet that follows current national dietary guideline. Further studies are warranted to assess potential utility of urinary PGE-M in assessing cancer prevention efficacy.

A systematic review of vascular and endothelial function: effects of fruit, vegetable and potassium intake

AIM

To review the relationships between: 1) Potassium and endothelial function; 2) Fruits and vegetables and endothelial function; 3) Potassium and other measures of vascular function; 4) Fruits and vegetables and other measures of vascular function.

DATA SYNTHESIS

An electronic search for intervention trials investigating the effect of potassium, fruits and vegetables on vascular function was performed in MEDLINE, EMBASE and the Cochrane Library. Potassium appears to improve endothelial function with a dose of >40 mmol/d, however the mechanisms for this effect remain unclear. Potassium may improve measures of vascular function however this effect may be dependent on the effect of potassium on blood pressure. The effect of fruit and vegetables on endothelial function independent of confounding variables is less clear. Increased fruit and vegetable intake may improve vascular function only in high risk populations.

CONCLUSION

Increasing dietary potassium appears to improve vascular function but the effect of increasing fruit and vegetable intake per se on vascular function is less clear.

Serum amyloid A-related inflammation is lowered by increased fruit and vegetable intake, while high-sensitive C-reactive protein, IL-6 and E-selectin remain unresponsive

The present study assessed whether increased fruit and vegetable (F&V) intake reduced the concentrations of the inflammatory marker serum amyloid A (SAA) in serum, HDL2 and HDL3 and whether the latter reduction influenced any of the functional properties of these HDL subfractions. The present study utilised samples from two previous studies: (1) the FAVRIT (Fruit and Vegetable Randomised Intervention Trial) study – hypertensive subjects (systolic blood pressure (BP) range 140–190 mmHg; diastolic BP range 90–110 mmHg) were randomised to receive a 1-, 3- or 6-portion F&V/d intervention for 8 weeks, and (2) the ADIT (Ageing and Dietary Intervention Trial) study – older subjects (65–85 years) were randomised to receive a 2- or 5-portion F&V/d intervention for 16 weeks. HDL2 and HDL3 were isolated by rapid ultracentrifugation. Measurements included the following: serum high-sensitive C-reactive protein (hsCRP) by an immunoturbidimetric assay; serum IL-6 and E-selectin and serum-, HDL2- and HDL3-SAA by ELISA procedures; serum-, HDL2- and HDL3-cholesterol ester transfer protein (CETP) activity by a fluorometric assay. Although the concentrations of hsCRP, IL-6 and E-selectin were unaffected by increasing F&V intake in both studies (P>0·05 for all comparisons), those of SAA in HDL3 decreased in the FAVRIT cohort (P= 0·049) and those in HDL2 and HDL3 decreased in the ADIT cohort (P= 0·035 and 0·032), which was accompanied by a decrease in the activity of CETP in HDL3 in the FAVRIT cohort (P= 0·010) and in HDL2 in the ADIT cohort (P= 0·030). These results indicate that SAA responds to increased F&V intake, while other inflammatory markers remain unresponsive, and this leads to changes in HDL2 and HDL3, which may influence their antiatherogenic potential. Overall, the present study provides tangible evidence of the effectiveness of increased F&V intake, which may be of use to health policy makers and the general public.

Flavonoid-rich fruit and vegetables improve microvascular reactivity and inflammatory status in men at risk of cardiovascular disease--FLAVURS: a randomized controlled trial

BACKGROUND

Observed associations between increased fruit and vegetable (F&V) consumption, particularly those F&Vs that are rich in flavonoids, and vascular health improvements require confirmation in adequately powered randomized controlled trials.

OBJECTIVE

This study was designed to measure the dose-response relation between high-flavonoid (HF), low-flavonoid (LF), and habitual F&V intakes and vascular function and other cardiovascular disease (CVD) risk indicators.

DESIGN

A single-blind, dose-dependent, parallel randomized controlled dietary intervention study was conducted. Male and female low-F&V consumers who had a ≥ 1.5-fold increased risk of CVD (n = 174) were randomly assigned to receive an HF F&V, an LF F&V, or a habitual diet, with HF and LF F&V amounts sequentially increasing by 2, 4, and 6 (+2, +4, and +6) portions/d every 6 wk over habitual intakes. Microvascular reactivity (laser Doppler imaging with iontophoresis), arterial stiffness [pulse wave velocity, pulse wave analysis (PWA)], 24-h ambulatory blood pressure, and biomarkers of nitric oxide (NO), vascular function, and inflammation were determined at baseline and at 6, 12, and 18 wk.

RESULTS

In men, the HF F&V diet increased endothelium-dependent microvascular reactivity (P = 0.017) with +2 portions/d (at 6 wk) and reduced C-reactive protein (P = 0.001), E-selectin (P = 0.0005), and vascular cell adhesion molecule (P = 0.0468) with +4 portions/d (at 12 wk). HF F&Vs increased plasma NO (P = 0.0243) with +4 portions/d (at 12 wk) in the group as a whole. An increase in F&Vs, regardless of flavonoid content in the groups as a whole, mitigated increases in vascular stiffness measured by PWA (P = 0.0065) and reductions in NO (P = 0.0299) in the control group.

CONCLUSION

These data support recommendations to increase F&V intake to ≥ 6 portions daily, with additional benefit from F&Vs that are rich in flavonoids, particularly in men with an increased risk of CVD.

Dose-response effect of fruit and vegetables on insulin resistance in people at high risk of cardiovascular disease: a randomized controlled trial

OBJECTIVE

The purpose of this randomized controlled trial was to investigate the dose-response effect of fruit and vegetable (F&V) intake on insulin resistance (IR) in people who are overweight and at high risk of cardiovascular disease (CVD).

RESEARCH DESIGN AND METHODS

A total of 105 participants (mean age 56 years) followed a 4-week washout diet (one to two portions of F&Vs per day). Ninety-two participants completed the washout and were randomized to receive one to two, four, or seven portions of F&Vs per day for 12 weeks. IR was assessed at the start and end of this 12-week period by the two-step euglycemic-hyperinsulinemic clamp. Compliance was monitored using a combination of 4-day food diaries and plasma biomarkers of F&V intake.

RESULTS

A total of 89 participants completed the study. Participants attained self-reported F&V intakes of 1.8, 3.8, and 7.0 portions per day (P < 0.001) per group. There was a significant linear increase in serum lutein status across the groups, indicating good compliance (P < 0.001), and body weight was maintained (P = 0.77). No significant difference was found between groups in terms of a change in measures of whole-body, peripheral, or hepatic IR or adiponectin multimers.

CONCLUSIONS

Increased consumption of F&Vs, as advocated in public-health advice, has no effect on IR in overweight individuals who are at high risk of CVD when body weight is maintained. Recent evidence from systematic reviews indicates that particular classes or types of F&Vs may have particular antidiabetic properties; hence, it is possible that benefits may only be observed in response to a more specific fruit or vegetable intervention.

Effect of diet on vascular health

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in the Western world in older people. Diet and lifestyle change can reduce CVD risk in older people, and this evidence base is reviewed. For example, diets low in trans fats can reduce CVD risk, while for saturated fats the CVD-lowering effect depends on what is substituted for the saturated fat. Diets rich in fish reduce CVD risk, although n-3 supplements have not been shown to have a consistent effect on CVD end-points. Antioxidant and B-group vitamin supplementation are unlikely to reduce CVD risk, but diets rich in these micronutrients (e.g. rich in fruits and vegetables and the Mediterranean diet) are associated with lower CVD risk, while, for the Mediterranean diet, this has been supported by randomized controlled trials. Maintaining a healthy weight and being physically active reduce CVD risk factors and CVD incidence and mortality.

Assessment of antioxidant, anti-inflammatory, anti-cholinesterase and cytotoxic activities of pomegranate (Punica granatum) leaves

This study evaluated antioxidant, anti-inflammatory, anti-cholinesterase and cytotoxic activities of extracts with different polarities (hexane, dichloromethane, ethyl acetate, ethanol and methanol) obtained from Punica granatum leaves. Total phenolics (8.8-127.3mg gallic acid equivalent/g dry weight), flavonoids (1.2-76.9mg quercetin equivalent/g dry weight), tannins (63.7-260.8mg catechin equivalent/kg dry weight) and anthocyanins (0.41-3.73mg cyanidin-3-glucoside equivalent/g dry weight) of different extracts were evaluated. The methanolic extract presented a good IC50 by DPPH and ABTS assays (5.62 and 1.31mg/l respectively). The strongest 5-lipoxygenase (5-LOX), acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibition activities were obtained for the ethanol extract (IC50 values of 6.20, 14.83 and 2.65mg/l, respectively) and the best cytotoxic activity against MCF-7 cells was obtained for the methanol extract (IC50=31mg/l). These important biological activities showed that P. granatum leaves could be a potential source of the active molecules intended for applications in pharmaceutical industry, but only after additional in vivo experiments.

Impact of the quantity and flavonoid content of fruits and vegetables on markers of intake in adults with an increased risk of cardiovascular disease: the FLAVURS trial

PURPOSE

Limited robust randomised controlled trials investigating fruit and vegetable (F&V) intake in people at risk of cardiovascular disease (CVD) exist. We aimed to design and validate a dietary strategy of increasing flavonoid-rich versus flavonoid-poor F&V consumption on nutrient biomarker profile.

METHODS

A parallel, randomised, controlled, dose-response dietary intervention study. Participants with a CVD relative risk of 1.5 assessed by risk scores were randomly assigned to one of the 3 groups: habitual (control, CT), high-flavonoid (HF) or low-flavonoid (LF) diets. While the CT group (n = 57) consumed their habitual diet throughout, the HF (n = 58) and LF (n = 59) groups sequentially increased their daily F&V intake by an additional 2, 4 and 6 portions for 6-week periods during the 18-week study.

RESULTS

Compliance to target numbers and types of F&V was broadly met and verified by dietary records, and plasma and urinary biomarkers. Mean (± SEM) number of F&V portions/day consumed by the HF and LF groups at baseline (3.8 ± 0.3 and 3.4 ± 0.3), 6 weeks (6.3 ± 0.4 and 5.8 ± 0.3), 12 weeks (7.0 ± 0.3 and 6.8 ± 0.3) and 18 weeks (7.6 ± 0.4 and 8.1 ± 0.4), respectively, was similar at baseline yet higher than the CT group (3.9 ± 0.3, 4.3 ± 0.3, 4.6 ± 0.4, 4.5 ± 0.3) (P = 0.015). There was a dose-dependent increase in dietary and urinary flavonoids in the HF group, with no change in other groups (P = 0.0001). Significantly higher dietary intakes of folate (P = 0.035), non-starch polysaccharides (P = 0.001), vitamin C (P = 0.0001) and carotenoids (P = 0.0001) were observed in both intervention groups compared with CT, which were broadly supported by nutrient biomarker analysis.

CONCLUSIONS

The success of improving nutrient profile by active encouragement of F&V intake in an intervention study implies the need for a more hands-on public health approach.

Greater variety in fruit and vegetable intake is associated with lower inflammation in Puerto Rican adults

BACKGROUND

Puerto Rican adults have prevalent metabolic abnormalities, but few studies have explored fruit and vegetable (FV) intake and coronary heart disease (CHD) risk in this population.

OBJECTIVE

We tested the hypothesis that greater FV intake and variety are associated with a lower 10-y risk of CHD and C-reactive protein (CRP) concentrations.

DESIGN

In a cross-sectional study of ≈1200 Puerto Rican adults aged 45-75 y, we assessed FV intake with a food-frequency questionnaire. The 10-y risk of CHD was assessed with the Framingham risk score (FRS) in participants free of cardiovascular disease. CRP was measured in fasting serum.

RESULTS

Variety, but not quantity, of FV intake was inversely associated with FRS after adjustment for the following: sex; waist circumference; perceived stress; alcohol use; intakes of energy, trans fatty acids, and saturated fatty acids; and use of supplements, cardiovascular medications, and diabetes medications (P = 0.02). However, the association was attenuated after adjustment for income (P = 0.11). Variety, but not quantity, was associated with a lower serum CRP concentration after adjustment for age, sex, smoking status, alcohol use, servings of FV, white blood cell count, diastolic blood pressure, diabetes, nonsteroidal antiinflammatory medication use, intakes of energy and vitamin B-6, waist circumference, perceived stress, and income. The adjusted odds of a high CRP concentration for those in the highest compared with the lowest tertile of FV variety was 0.68 (95% CI: 0.49, 0.94).

CONCLUSIONS

FV variety, but not quantity, appears to be important in reducing inflammation. Although the results are suggestive, larger studies are needed to confirm a possible association with CHD risk score.