Recent observational and clinical studies have raised interest in the potential health effects of cranberry consumption, an association that appears to be due to the phytochemical content of this fruit. The profile of cranberry bioactives is distinct from that of other berry fruit, being rich in A-type proanthocyanidins (PACs) in contrast to the B-type PACs present in most other fruit. Basic research has suggested a number of potential mechanisms of action of cranberry bioactives, although further molecular studies are necessary. Human studies on the health effects of cranberry products have focused principally on urinary tract and cardiovascular health, with some attention also directed to oral health and gastrointestinal epithelia. Evidence suggesting that cranberries may decrease the recurrence of urinary tract infections is important because a nutritional approach to this condition could lower the use of antibiotic treatment and the consequent development of resistance to these drugs. There is encouraging, but limited, evidence of a cardioprotective effect of cranberries mediated via actions on antioxidant capacity and lipoprotein profiles. The mixed outcomes from clinical studies with cranberry products could result from interventions testing a variety of products, often uncharacterized in their composition of bioactives, using different doses and regimens, as well as the absence of a biomarker for compliance to the protocol. Daily consumption of a variety of fruit is necessary to achieve a healthy dietary pattern, meet recommendations for micronutrient intake, and promote the intake of a diversity of phytochemicals. Berry fruit, including cranberries, represent a rich source of phenolic bioactives that may contribute to human health.
Background: There is much speculation with regard to the potential cardioprotective benefits of equol, a microbial-derived metabolite of the isoflavone daidzein, which is produced in the large intestine after soy intake in 30% of Western populations. Although cross-sectional and retrospective data support favorable associations between the equol producer (EP) phenotype and cardiometabolic health, few studies have prospectively recruited EPs to confirm this association.Objective: The aim was to determine whether the acute vascular benefits of isoflavones differ according to EP phenotype and subsequently investigate the effect of providing commercially produced S-(–)equol to non-EPs.Design: We prospectively recruited male EPs and non-EPs (n = 14/group) at moderate cardiovascular risk into a double-blind, placebo-controlled crossover study to examine the acute effects of soy isoflavones (80-mg aglycone equivalents) on arterial stiffness [carotid-femoral pulse-wave velocity (cfPWV)], blood pressure, endothelial function (measured by using the EndoPAT 2000; Itamar Medical), and nitric oxide at baseline (0 h) and 6 and 24 h after intake. In a separate assessment, non-EPs consumed 40 mg S-(–)equol with identical vascular measurements performed 2 h after intake.Results: After soy intake, cfPWV significantly improved in EPs at 24 h (cfPWV change from 0 h: isoflavone, −0.2 ± 0.2 m/s; placebo, 0.6 ± 0.2 m/s; P < 0.01), which was significantly associated with plasma equol concentrations (R = −0.36, P = 0.01). No vascular effects were observed in EPs at 6 h or in non-EPs at any time point. Similarly, no benefit of commercially produced S-(–)equol was observed in non-EPs despite mean plasma equol concentrations reaching 3.2 μmol/L.Conclusions: Acute soy intake improved cfPWV in EPs, equating to an 11–12% reduced risk of cardiovascular disease if sustained. However, a single dose of commercially produced equol had no cardiovascular benefits in non-EPs. These data suggest that the EP phenotype is critical in unlocking the vascular benefits of equol in men, and long-term trials should focus on confirming the implications of EP phenotype on cardiovascular health. This trial was registered at clinicaltrials.gov as NCT01530893.
Cardiovascular disease is a chronic disease influenced by many factors, with activated blood platelets being one of them. Platelets play a central role in the formation of plaques within blood vessels, contributing to early inflammatory events. Consumption of diets rich in plant-based products protects against the development of cardiovascular disease. Polyphenols, which are secondary plant metabolites found in a wide range of foodstuffs and beverages, may be partially responsible for these effects. Their protective properties include inhibitory effects on platelet function in vitro and in vivo. However, the bioavailability of many polyphenols is poor and it is unclear whether sufficient quantities can be obtained by dietary means to exert protective effects. Consequently, this review summarizes 25 well-controlled human intervention studies examining the effect of polyphenol-rich diets on platelet function. These studies report a huge variety of research methods, study designs, and study subjects, resulting in controversial assertions. One consistent finding is that cocoa-related products, however, have platelet-inhibiting effects when consumed in moderate amounts. To assess whether other classes of dietary polyphenols, or their metabolites, also beneficially affect platelet function requires more well-controlled intervention studies as well as the adoption of more uniform methods to assess platelet aggregation and activation.
The association between excess cortisol and various parameters of metabolic syndrome including hypertension, insulin resistance and dyslipidaemia is increasingly recognised. The present single-blind randomised placebo-controlled cross-over study compared the effect of polyphenol-rich dark chocolate (DC) on biomarkers of glucose metabolism, lipid profile, and blood pressure (BP) in females with BMI $ 25 kg m À2 (n ¼ 21) and females with BMI < 25 kg m À2 (n ¼ 21). Volunteers consumed 20 g of DC containing 500 mg polyphenols or a placebo DC with negligible polyphenol-content daily for 4 weeks, separated by a 2-week washout period. Systolic BP and diastolic BP decreased after 4 weeks of polyphenol-rich DC. Placebo raised fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR) and salivary cortisol, an effect that was significantly different from polyphenol-rich DC which had a negligible effect on fasting insulin, HOMA-IR and salivary cortisol. Females with BMI $ 25 kg m À2 responded less favourably to placebo than lean females and consequently had higher fasting insulin and HOMA-IR, in addition to a lower quantitative sensitivity check index (QUICKI) after ingestion of placebo compared to polyphenol-rich DC. No significant changes in lipid profile were observed. This study provides evidence for the metabolic benefits of consuming polyphenol-rich dark chocolate while demonstrating the possibility of adverse effects occurring with polyphenol-poor chocolate placebo. Methods DesignThe study used a single-blind randomised placebo-controlled cross-over design where each subject acted as their own control. Following a 1-week run-in phase, eligible subjects were randomly assigned to receive 20 g DC containing 500 mg polyphenols or
As concentrations of 100 μmol/L are unlikely to be reached in the circulation, it is doubtful whether consumption of dietary phenolics in nutritionally attainable amounts plays a major role in inhibition of platelet activation and aggregation in humans.
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