Intake Of Polyphenol-rich Foods Research Articles

Total polyphenol excretion and blood pressure in subjects at high cardiovascular risk

Background and aims Dietary factors are critical for the prevention and treatment of hypertension, but data on the effects of specific nutrients on blood pressure (BP) are scarce. The aim of this study was to assess the relationship between total polyphenol excretion (TPE) in urine, as an objective measurement of total polyphenol intake and BP in an elderly population at high cardiovascular risk. Methods and results Cross-sectional substudy of 589 high-risk participants entering in the PREDIMED trial. BP was measured and TPE was determined in urine by Folin–Ciocalteu assay. A significant positive association was observed between TPE in urine and daily intake of fruit and vegetables (F&V), coffee or wine after adjusting for potential confounders. The intake of 100 g of F&V (Beta = 0.150; P < 0.001) had a greater contribution to TPE than 100 mL of coffee (Beta = 0.141; P = 0.001), and the latter two foods contributed more than the consumption of 100 mL of wine (Beta = 0.120; P = 0.019). An inverse association was observed between urinary TPE and the prevalence of hypertension. Participants in the highest quartile of urinary TPE had a reduced prevalence of hypertension compared to those in the lowest quartile (Odds Ratio = 0.64; 95% confidence interval 0.45 to 0.92; P = 0.015). Systolic and diastolic BP were inversely associated with urinary TPE after adjustment for potential confounders ( P = 0.024 and P = 0.003, respectively). Conclusions Polyphenol intake, assessed via TPE in urine, was negatively associated with BP levels and prevalence of hypertension in an elderly Mediterranean population at high cardiovascular risk. Participants with the highest intake of polyphenol-rich foods showed the lowest BP measurements.

Effects of Pomegranate Juice and Extract Polyphenols on Platelet Function

Several studies have shown that polyphenols reduce cardiovascular accidents in high-risk patients; in particular, the inhibition of platelet function may be responsible for part of this benefit. This research studied the antiplatelet effect of Wonderful variety pomegranate (Punica granatum) products, which contain primarily hydrolyzed tannins such as ellagitannins. We have investigated in vitro the effects of treatment with either pomegranate juice (PJ) or the polyphenol-rich extract from pomegranate fruit (POMx) on platelet aggregation, calcium mobilization, thromboxane A(2) production, and hydrogen peroxide formation, induced by collagen and arachidonic acid. PJ and POMx reduce all the platelet responses studied. POMx showed a stronger action in reducing platelet activation; moreover, POMx is active at the concentration that it is possible to obtain after polyphenol-rich food intake (2 microM). These results demonstrated that the cardiovascular health benefits of pomegranate may in part be related to the ability of polyphenols to inhibit platelet function. In fact, PJ and pomegranate extract have similar effects at concentrations expected for normal intake.

Urinary flavonoids and phenolic acids as biomarkers of intake for polyphenol-rich foods

Estimation of dietary intake of polyphenols is difficult, due to limited availability of food composition data and bias inherent to dietary assessment methods. The aim of the present study was to evaluate the associations between the intake of polyphenol-rich foods and the urinary excretion of several phenolic compounds and therefore explore whether these phenolic compounds could be used as a biomarker of intake. Fifty-three participants of the SU.VI.MAX study (a randomised primary-prevention trial evaluating the effect of daily antioxidant supplementation on chronic diseases) collected a 24 h urine and a spot urine sample and filled a dietary record during a 2 d period. Thirteen polyphenols and metabolites, chlorogenic acid, caffeic acid, m-coumaric acid, gallic acid, 4-O-methylgallic acid, quercetin, isorhamnetin, kaempferol, hesperetin, naringenin, phloretin, enterolactone and enterodiol, were measured using HPLC-electrospray ionisation-MS-MS. In spot samples apple consumption was positively correlated to phloretin, grapefruit consumption to naringenin, orange to hesperetin, citrus fruit consumption to both naringenin and hesperetin, with r coefficients ranging from 0.31 to 0.57 (P < 0.05). The combination of fruits and/or fruit juices was positively correlated to gallic acid and 4-O-methylgallic acid, isorhamnetin, kaempferol, hesperetin, naringenin and phloretin (r 0.24-0.44, P < 0.05). Coffee consumption was positively correlated to caffeic and chlorogenic acids (r 0.29 and 0.63, P < 0.05 respectively). Black tea and wine consumption were positively correlated with gallic and 4-O-methylgallic acids (r 0.37-0.54, P < 0.001). The present results suggest that several polyphenols measured in a spot urine sample can be used as biomarkers of polyphenol-rich food intake.