| Autor: |
Woolf EK; Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO, USA. sarah.johnson@colostate.edu., Terwoord JD; Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA., Litwin NS; Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO, USA. sarah.johnson@colostate.edu., Vazquez AR; Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO, USA. sarah.johnson@colostate.edu., Lee SY; Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO, USA. sarah.johnson@colostate.edu., Ghanem N; Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO, USA. sarah.johnson@colostate.edu., Michell KA; Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO, USA. sarah.johnson@colostate.edu., Smith BT; Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO, USA. sarah.johnson@colostate.edu., Grabos LE; Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO, USA. sarah.johnson@colostate.edu., Ketelhut NB; Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA., Bachman NP; Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA., Smith ME; Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA., Le Sayec M; Department of Nutritional Sciences, School of Life Course and Population Sciences, King's College London, London, England, UK., Rao S; Department of Clinical Sciences, Colorado State University, Fort Collins, CO, USA., Gentile CL; Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO, USA. sarah.johnson@colostate.edu., Weir TL; Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO, USA. sarah.johnson@colostate.edu., Rodriguez-Mateos A; Department of Nutritional Sciences, School of Life Course and Population Sciences, King's College London, London, England, UK., Seals DR; Department of Integrative Physiology, University of Colorado, Boulder, CO, USA., Dinenno FA; Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA., Johnson SA; Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO, USA. sarah.johnson@colostate.edu. |
| Abstrakt: |
Estrogen-deficient postmenopausal women have oxidative stress-mediated suppression of endothelial function that is exacerbated by high blood pressure. Previous research suggests blueberries may improve endothelial function through reductions in oxidative stress, while also exerting other cardiovascular benefits. The objective of this study was to examine the efficacy of blueberries to improve endothelial function and blood pressure in postmenopausal women with above-normal blood pressure, and to identify potential mechanisms for improvements in endothelial function. A randomized, double-blind, placebo-controlled, parallel-arm clinical trial was performed, where postmenopausal women aged 45-65 years with elevated blood pressure or stage 1-hypertension (total n = 43, endothelial function n = 32) consumed 22 g day -1 of freeze-dried highbush blueberry powder or placebo powder for 12 weeks. Endothelial function was assessed at baseline and 12 weeks through ultrasound measurement of brachial artery flow-mediated dilation (FMD) normalized to shear rate area under the curve (FMD/SR AUC ) before and after intravenous infusion of a supraphysiologic dose of ascorbic acid to evaluate whether FMD improvements were mediated by reduced oxidative stress. Hemodynamics, arterial stiffness, cardiometabolic blood biomarkers, and plasma (poly)phenol metabolites were assessed at baseline and 4, 8, and 12 weeks, and venous endothelial cell protein expression was assessed at baseline and 12 weeks. Absolute FMD/SR AUC was 96% higher following blueberry consumption compared to baseline ( p < 0.05) but unchanged in the placebo group ( p > 0.05), and changes from baseline to 12 weeks were greater in the blueberry group than placebo (+1.09 × 10 -4 ± 4.12 × 10 -5 vs. +3.82 × 10 -6 ± 1.59 × 10 -5 , p < 0.03, respectively). The FMD/SR AUC response to ascorbic acid infusion was lower ( p < 0.05) at 12 weeks compared to baseline in the blueberry group with no change in the placebo group ( p > 0.05). The sum of plasma (poly)phenol metabolites increased at 4, 8, and 12 weeks in the blueberry group compared to baseline, and were higher than the placebo group (all p < 0.05). Increases in several plasma flavonoid and microbial metabolites were also noted. No major differences were found for blood pressure, arterial stiffness, blood biomarkers, or endothelial cell protein expression following blueberry consumption. These findings suggest daily consumption of freeze-dried blueberry powder for 12 weeks improves endothelial function through reduced oxidative stress in postmenopausal women with above-normal blood pressure. The clinical trial registry number is NCT03370991 (https://clinicaltrials.gov). |
