Dr. Rodriguez-Mateos is a Junior Research Group Leader at the Division of Cardiology, Pulmunology and Vascular Medicine of the University of Dusseldorf, Germany. She received her PhD in Food Chemistry from the University of Reading, UK, in 2006 and then joined Professor Jeremy Spencer’s group as a postdoctoral research fellow in the Hugh Sinclair Unit of Human Nutrition at the Department of Food and Nutritional Sciences of the University of Reading. She has considerable experience with the analysis of phytochemicals, in particular flavonoids, in human biofluids, and in conducting human intervention studies designed to understand the biovailability and biological activity of dietary flavonoids. She is currently investigating the factors that affect the absorption, metabolism and efficacy of dietary polyphenols in the context of cardiovascular function, using human intervention trials and experimental models.
Effects of blueberry polyphenols on vascular function in healthy men
Ana Rodriguez-Mateos, Catarina Rendeiro, Trevor W. George and Jeremy P. E. Spencer Department of Food and Nutritional Sciences, School of Chemistry, Food and Pharmacy, University of Reading, PO Box 226, RG2 6AP, Reading, UK
Blueberries are a rich source of polyphenols, in particular anthocyanins, procyanidins and hydroxycinnamic acids (1). Although blueberry-enriched diets have been shown to improve vascular function in animal models (2-7), currently very limited data exists regarding the effects of blueberry consumption on human vascular function. The aim of this work was to investigate whether: 1) acute blueberry consumption improves endothelial function in healthy men; 2) blueberry polyphenols-mediated effects on endothelial function follow a dose-dependency; 3) plasma polyphenol metabolites are correlated with the effects on endothelial function; 4) food processing affects the blueberry polyphenol-mediated vascular effects. Three randomized, controlled, double blind, cross-over human intervention trials were conducted in 21 healthy male subjects where they consume a blueberry drink (319, 637, 766, 1466 and 1791 mg of total polyphenols (TP)), a blueberry baked product or macro- and micro-nutrient controls. Measurements were taken at baseline after overnight fast and at 1, 2, 4 and 6 h post consumption. The primary endpoint was flow-mediated dilation (FMD). Secondary endpoints were plasma polyphenol metabolites and other markers of vascular function.
Our results show that there were significant increases in FMD at 1,2 and 6 hour after ingestion of blueberry polyphenols taken as a blueberry drink using freeze-dried blueberry dissolved in water or as a blueberry-containing baked product. At 1 hour post-consumption, endothelial function increased in a linear fashion up to the 766 mg intake level, after which the vascular response plateau and decreased slightly at the higher intake levels. A significant increase in plasma levels of polyphenol metabolites was observed after blueberry consumption.
In conclusion, blueberry polyphenol intake improves endothelial function in healthy men, and the vascular improvements correlate in time with changes in plasma polyphenol metabolites. A linear dose-dependency was observed at the lower range tested but not at the highest concentrations. Food processing did not seem to affect the improvements in endothelial function exerted by blueberry consumption.
Key words: Blueberries, polyphenols, endothelial function, flow-mediated dilation, food processing
1. Rodriguez-Mateos A, Cifuentes-Gomez T, Tabatabaee S, Lecras C, Spencer JP. Procyanidin, Anthocyanin, and Chlorogenic Acid Contents of Highbush and Lowbush Blueberries. J Agric Food Chem 2012.
2. Kalea AZ, Clark K, Schuschke DA, Klimis-Zacas DJ. Vascular reactivity is affected by dietary consumption of wild blueberries in the Sprague-Dawley rat. J Med Food 2009;12(1):21-8.
3. Kalea AZ, Clark K, Schuschke DA, Kristo AS, Klimis-Zacas DJ. Dietary enrichment with wild blueberries (Vaccinium angustifolium) affects the vascular reactivity in the aorta of young spontaneously hypertensive rats. J Nutr Biochem 2010;21(1):14-22.
4. Kristo AS, Kalea AZ, Schuschke DA, Klimis-Zacas DJ. A wild blueberry-enriched diet (Vaccinium angustifolium) improves vascular tone in the adult spontaneously hypertensive rat. J Agric Food Chem 2010;58(22):11600-5.
5. Norton C, Kalea AZ, Harris PD, Klimis-Zacas DJ. Wild blueberry-rich diets affect the contractile machinery of the vascular smooth muscle in the Sprague-Dawley rat. J Med Food 2005;8(1):8-13.
6. Rodriguez-Mateos A, Ishisaka A, Mawatari K, Vidal-Diez A, Spencer JP, Terao J. Blueberry intervention improves vascular reactivity and lowers blood pressure in high-fat-, high-cholesterol-fed rats. Br J Nutr 2012:1-9.
7. Shaughnessy KS, Boswall IA, Scanlan AP, Gottschall-Pass KT, Sweeney MI. Diets containing blueberry extract lower blood pressure in spontaneously hypertensive stroke-prone rats. Nutr Res 2009;29(2):130-8.