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Hollman P.C.H.,Wageningen University | Cassidy A.,University of East Anglia | Heinonen M.,University of Helsinki | Richelle M.,Nestle | And 5 more authors.
Journal of Nutrition | Year: 2011

Human studies provide evidence for beneficial effects of polyphenol-rich foods on cardiovascular health. The antioxidant activity of polyphenols potentially explains these effects, but is the antioxidant activity a reliable predictor for these effects? An International Life Sciences Institute Europe working group addressed this question and explored the potential of antioxidant claims for polyphenols in relation to cardiovascular health by using the so-called Process for the Assessment of Scientific Support for Claims on Foods project criteria. In this process, analytical aspects of polyphenols, their occurrence in foods, dietary intake, and bioavailability were reviewed. Human studies on polyphenols and cardiovascular health were reviewed together with methods for biomarkers of oxidative damage and total antioxidant capacity (TAC). In retrospective studies, F2-isoprostanes and oxidized LDL, the most reliable biomarkers of lipid peroxidation, and measures for TAC showed the expected differences between cardiovascular disease patients and healthy controls, but prospective studies are lacking, and a causal relationship between these biomarkers and cardiovascular health could not be established. Therefore, the physiological relevance of a potential change in these biomarkers is unclear. We found limited evidence that some types of polyphenol-rich products modify these biomarkers in humans. A direct antioxidant effect of polyphenols in vivo is questionable, however, because concentrations in blood are low compared with other antioxidants and extensive metabolism following ingestion lowers their antioxidant activity. Therefore, the biological relevance of direct antioxidant effects of polyphenols for cardiovascular health could not be established. Overall, although some polyphenol-rich foods exert beneficial effects on some biomarkers of cardiovascular health, there is no evidence that this is caused by improvements in antioxidant function biomarkers (oxidative damage or antioxidant capacity). © 2011 American Society for Nutrition.

Ekstrom A.M.,Karolinska Institutet | Serafini M.,Antioxidant Research Laboratory | Nyren O.,Karolinska Institutet | Wolk A.,Karolinska Institutet | And 3 more authors.
Annals of Oncology | Year: 2011

Background: To study the impact of the dietary antioxidant quercetin on risk of gastric adenocarcinoma. Patients and methods: Using data from a large Swedish population-based case-control study of gastric cancer (505 cases and 1116 controls), we studied the association between quercetin and risk of anatomic (cardia/noncardia) and histological (intestinal and diffuse) subtypes of gastric cancer. Results: We found strong inverse associations between quercetin and the risk of noncardia gastric adenocarcinoma, with an adjusted odds ratio (OR) of 0.57 (95% confidence interval 0.40-0.83) for the highest quintile (≥11.9 mg) of daily quercetin intake relative to the lowest quintile of intake (<4 mg quercetin/day), supported by a significant decreasing linear trend (P value < 0.001). Similar findings were observed for the intestinal and diffuse subtype. For cardia cancer, we found a less evident and nonsignificant inverse relationship. The protection of quercetin appeared to be stronger among female smokers, with the OR leveled of at values <0.2 in quintiles 3-5 (>6 mg quercetin/day). Conclusions: High dietary quercetin intake is inversely related to the risk of noncardia gastric adenocarcinoma, and the protection appears to be particularly strong for women exposed to oxidative stress, such as tobacco smoking. © The Author 2010. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved.

Villano D.,Food and Nutrition Unit | Lettieri-Barbato D.,Food and Nutrition Unit | Guadagni F.,Food and Nutrition Unit | Schmid M.,Beverages Partners Worldwide Europe AG | Serafini M.,Antioxidant Research Laboratory
Food Chemistry | Year: 2012

We evaluated the ability of a ready-to-drink oolong tea (OOL) to modulate plasma antioxidant status in healthy subjects, compared to a placebo drink (PLA) without oolong extract but with ascorbic acid. In vitro, ascorbic acid was the only contributor to ferric reducing antioxidant power (FRAP) and total radical-trapping antioxidant parameter (TRAP) assay of PLA. Ascorbic acid contributed 16.5% and 9.7% of the antioxidant capacity of OOL. In vivo, ingestion of 500 mL of OOL significantly increased plasma TRAP at 30 min and 1 h, compared to 500 mL of PLA, which was ineffective. Plasma FRAP significantly increased at 1, 2 and 4 h for OOL and at 2 h for PLA. Both PLA and OOL significantly increased urinary FRAP over 0-5 h. Urinary FRAP levels went back to baseline at 5 h for PLA tea and remained higher for OOL tea in the interval time 5-12 h (p < 0.01). OOL represents a dietary source of antioxidants able to modulate antioxidant status in humans. © 2011 Elsevier Ltd. All rights reserved.

Flammer A.J.,University of Zurich | Flammer A.J.,Rochester College | Sudano I.,University of Zurich | Wolfrum M.,University of Zurich | And 12 more authors.
European Heart Journal | Year: 2012

Aims Flavanol-rich chocolate (FRC) is beneficial for vascular and platelet function by increasing nitric oxide bioavailability and decreasing oxidative stress. Congestive heart failure (CHF) is characterized by impaired endothelial and increased platelet reactivity. As statins are ineffective in CHF, alternative therapies are a clinical need. We therefore investigated whether FRC might improve cardiovascular function in patients with CHF.Methods and resultsTwenty patients with CHF were enrolled in a double-blind, randomized placebo-controlled trial, comparing the effect of commercially available FRC with cocoa-liquor-free control chocolate (CC) on endothelial and platelet function in the short term (2 h after ingestion of a chocolate bar) and long term (4 weeks, two chocolate bars/day). Endothelial function was assessed non-invasively by flow-mediated vasodilatation of the brachial artery. Flow-mediated vasodilatation significantly improved from 4.98 ± 1.95 to 5.98 ± 2.32 (P = 0.045 and 0.02 for between-group changes) 2h after intake of FRC to 6.86 ± 1.76 after 4 weeks of daily intake (P = 0.03 and 0.004 for between groups). No effect on endothelial-independent vasodilatation was observed. Platelet adhesion significantly decreased from 3.9 ± 1.3 to 3.0 ± 1.3 (P = 0.03 and 0.05 for between groups) 2 h after FRC, an effect that was not sustained at 2 and 4 weeks. Cocoa-liquor-free CC had no effect, either on endothelial function or on platelet function. Blood pressure and heart rate did not change in either group. Conclusion Flavanol-rich chocolate acutely improves vascular function in patients with CHF. A sustained effect was seen after daily consumption over a 4-week period, even after 12 h abstinence. These beneficial effects were paralleled by an inhibition of platelet function in the presence of FRC only. © 2012 The Author.

Lettieri-Barbato D.,Food and Nutrition Unit | Villano D.,Food and Nutrition Unit | Beheydt B.,Puratos Group Industrialaan 25 | Guadagni F.,Food and Nutrition Unit | And 2 more authors.
Food Chemistry | Year: 2012

The association between in vitro antioxidant capacity of dark chocolates with different cocoa percentage and the in vivo response on antioxidant status was investigated. In a randomized crossover design, 15 healthy volunteer consumed 100 g of high antioxidants dark chocolate (HADC) or dark chocolate (DC). In vitro, HADC displayed a higher Total Antioxidant Capacity (TAC) than DC. In vivo, plasma TAC significantly peaked 2 h after ingestion of both chocolates. TAC levels went back to zero 5 h after DC ingestion whilst levels remained significantly higher for HADC. HADC induced a significantly higher urinary TAC in the 5-12 h interval time than DC. No change was detected in urinary excretion of F2-isoprostanes. Plasma thiols and triacylglycerol (TG) levels significantly increased for both chocolate with a peak at 2 h remaining significantly higher for DC after 5 h respect to HADC. Results provide evidence of a direct association between antioxidant content of chocolate and the extent of in vivo response on plasma antioxidant capacity. © 2011 Elsevier Ltd. All rights reserved.

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