19 research outputs found
Quantitative Analysis of Vasodilatory Action of Quercetin on Intramural Coronary Resistance Arteries of the Rat In Vitro
Background: Dietary quercetin improves cardiovascular health, relaxes some vascular smooth muscle and has been demonstrated to serve as a substrate for the cyclooxygenase enzyme. Aims: 1. To test quantitatively a potential direct vasodilatory effect on intramural coronary resistance artery segments, in different concentrations. 2. To scale vasorelaxation at different intraluminal pressure loads on such vessels of different size. 3. To test the potential role of prostanoids in vasodilatation induced by quercetin. Methods: Coronary arterioles (70-240 mu m) were prepared from 24 rats and pressurized in PSS, using a pressure microangiometer. Results: The spontaneous tone that developed at 50 mmHg was relaxed by quercetin in the 10(-9) moles/lit concentration (p<0.05), while 10(-5) moles/lit caused full relaxation. Significant relaxation was observed at all pressure levels (10-100 mmHg) at 10(-7) moles/lit concentration of quercetin. The cyclooxygenase blocker indomethacin (10(-5) moles/lit) induced no relaxation but contraction when physiological concentrations of quercetin were present in the tissue bath (p<0.02 with Anova), this contraction being more prominent in smaller vessels and in the higher pressure range (p<0.05, Pearson correlation). A further 2-8% contraction could be elicited by the NO blocker L-NAME (10(-4) moles/lit). Conclusion: These results demonstrate that circulating levels of quercetin (10(-7) moles/lit) exhibit a substantial coronary vasodilatory effect. The extent of it is commeasurable with that of several other physiological mechanisms of coronary blood flow control. At least part of this relaxation is the result of an altered balance toward the production of endogenous vasodilatory prostanoids in the coronary arteriole wall
Polyphenol intake and mortality risk: a re-analysis of the PREDIMED trial
Background: Polyphenols may lower the risk of cardiovascular disease (CVD) and other chronic diseases due to
their antioxidant and anti-inflammatory properties, as well as their beneficial effects on blood pressure, lipids and
insulin resistance. However, no previous epidemiological studies have evaluated the relationship between the intake
of total polyphenols intake and polyphenol subclasses with overall mortality. Our aim was to evaluate whether
polyphenol intake is associated with all-cause mortality in subjects at high cardiovascular risk.
Methods: We used data from the PREDIMED study, a 7,447-participant, parallel-group, randomized, multicenter,
controlled five-year feeding trial aimed at assessing the effects of the Mediterranean Diet in primary prevention of
cardiovascular disease. Polyphenol intake was calculated by matching food consumption data from repeated food
frequency questionnaires (FFQ) with the Phenol-Explorer database on the polyphenol content of each reported
food. Hazard ratios (HR) and 95% confidence intervals (CI) between polyphenol intake and mortality were estimated
using time-dependent Cox proportional hazard models.
Results: Over an average of 4.8 years of follow-up, we observed 327 deaths. After multivariate adjustment, we
found a 37% relative reduction in all-cause mortality comparing the highest versus the lowest quintiles of total
polyphenol intake (hazard ratio (HR) = 0.63; 95% CI 0.41 to 0.97; P for trend = 0.12). Among the polyphenol subclasses,
stilbenes and lignans were significantly associated with reduced all-cause mortality (HR =0.48; 95% CI 0.25 to 0.91; P for
trend = 0.04 and HR = 0.60; 95% CI 0.37 to 0.97; P for trend = 0.03, respectively), with no significant associations apparent
in the rest (flavonoids or phenolic acids).
Conclusions: Among high-risk subjects, those who reported a high polyphenol intake, especially of stilbenes and
lignans, showed a reduced risk of overall mortality compared to those with lower intakes. These results may be useful
to determine optimal polyphenol intake or specific food sources of polyphenols that may reduce the risk of all-cause
mortality.
Clinical trial registration: ISRCTN35739639
Polyphenol Levels Are Inversely Correlated with Body Weight and Obesity in an Elderly Population after 5 Years of Follow Up (The Randomised PREDIMED Study)
Overweight and obesity have been steadily increasing in recent years and currently
represent a serious threat to public health. Few human studies have investigated the relationship
between polyphenol intake and body weight. Our aim was to assess the relationship between urinary
polyphenol levels and body weight. A cross-sectional study was performed with 573 participants
from the PREDIMED (Prevención con Dieta Mediterránea) trial (ISRCTN35739639). Total polyphenol
levels were measured by a reliable biomarker, total urinary polyphenol excretion (TPE), determined
by the Folin-Ciocalteu method in urine samples. Participants were categorized into five groups
according to their TPE at the fifth year. Multiple linear regression models were used to assess the
relationships between TPE and obesity parameters; body weight (BW), body mass index (BMI),
waist circumference (WC), and waist-to-height ratio (WHtR). After a five years follow up, significant
inverse correlations were observed between TPE at the 5th year and BW (β = −1.004; 95% CI: −1.634
to −0.375, p = 0.002), BMI (β = −0.320; 95% CI: −0.541 to −0.098, p = 0.005), WC (β = −0.742; 95% CI:
−1.326 to −0.158, p = 0.013), and WHtR (β = −0.408; 95% CI: −0.788 to −0.028, p = 0.036) after
adjustments for potential confounders. To conclude, a greater polyphenol intake may thus contribute
to reducing body weight in elderly people at high cardiovascular risk.
Nutrients 2017, 9, 452; doi:10.3390/nu905045
Phenol-Explorer 3.0: a major update of the Phenol-Explorer database to incorporate data on the effects of food processing on polyphenol content
International audiencePolyphenols are a major class of bioactive phytochemicals whose consumption may play a role in the prevention of a number of chronic diseases such as cardiovascular diseases, type II diabetes and cancers. Phenol-Explorer, launched in 2009, is the only freely available web-based database on the content of polyphenols in food and their in vivo metabolism and pharmacokinetics. Here we report the third release of the database (Phenol-Explorer 3.0), which adds data on the effects of food processing on polyphenol contents in foods. Data on >100 foods, covering 161 polyphenols or groups of polyphenols before and after processing, were collected from 129 peer-reviewed publications and entered into new tables linked to the existing relational design. The effect of processing on polyphenol content is expressed in the form of retention factor coefficients, or the proportion of a given polyphenol retained after processing, adjusted for change in water content. The result is the first database on the effects of food processing on polyphenol content and, following the model initially defined for Phenol-Explorer, all data may be traced back to original sources. The new update will allow polyphenol scientists to more accurately estimate polyphenol exposure from dietary surveys
Polyphenol intake and mortality risk: a re-analysis of the PREDIMED trial
Background: Polyphenols may lower the risk of cardiovascular disease (CVD) and other chronic diseases due to
their antioxidant and anti-inflammatory properties, as well as their beneficial effects on blood pressure, lipids and
insulin resistance. However, no previous epidemiological studies have evaluated the relationship between the intake
of total polyphenols intake and polyphenol subclasses with overall mortality. Our aim was to evaluate whether
polyphenol intake is associated with all-cause mortality in subjects at high cardiovascular risk.
Methods: We used data from the PREDIMED study, a 7,447-participant, parallel-group, randomized, multicenter,
controlled five-year feeding trial aimed at assessing the effects of the Mediterranean Diet in primary prevention of
cardiovascular disease. Polyphenol intake was calculated by matching food consumption data from repeated food
frequency questionnaires (FFQ) with the Phenol-Explorer database on the polyphenol content of each reported
food. Hazard ratios (HR) and 95% confidence intervals (CI) between polyphenol intake and mortality were estimated
using time-dependent Cox proportional hazard models.
Results: Over an average of 4.8 years of follow-up, we observed 327 deaths. After multivariate adjustment, we
found a 37% relative reduction in all-cause mortality comparing the highest versus the lowest quintiles of total
polyphenol intake (hazard ratio (HR) = 0.63; 95% CI 0.41 to 0.97; P for trend = 0.12). Among the polyphenol subclasses,
stilbenes and lignans were significantly associated with reduced all-cause mortality (HR =0.48; 95% CI 0.25 to 0.91; P for
trend = 0.04 and HR = 0.60; 95% CI 0.37 to 0.97; P for trend = 0.03, respectively), with no significant associations apparent
in the rest (flavonoids or phenolic acids).
Conclusions: Among high-risk subjects, those who reported a high polyphenol intake, especially of stilbenes and
lignans, showed a reduced risk of overall mortality compared to those with lower intakes. These results may be useful
to determine optimal polyphenol intake or specific food sources of polyphenols that may reduce the risk of all-cause
mortality.
Clinical trial registration: ISRCTN35739639