Date of Completion

1-29-2016

Embargo Period

1-26-2019

Keywords

Polyphenol, Cholesterol, Anthocyanins, Proanthocyanidins, Bioavailability, Metabolism

Major Advisor

Bradley W. Bolling

Associate Advisor

Ji‐Young Lee

Associate Advisor

Ock Chun

Associate Advisor

Marcy Balunas

Associate Advisor

William Baker

Field of Study

Nutritional Science

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Dietary polyphenols are non-essential phytonutrients that are extensively metabolized upon consumption. We hypothesized that the bioavailability of polyphenol metabolites is more important than unmetabolized polyphenols for the health promoting effects of polyphenol-rich foods. First, we developed a more complete polyphenol profile for almond, by characterizing its extensively metabolized polyphenol composition. In almond, hydrolysable tannin content was 54.7 ± 2.3 mg ellagic acid and 27.4 ± 7.3 mg gallic acid per 100 g almond among varieties. Resveratrol-3-O-glucoside was identified in almond extracts, with 7.19–8.52 μg/100 g almond. Second, we determined the efficiency by which aronia berry polyphenols are metabolized in an acute pharmacokinetic study in humans. Polyphenol metabolites constituted at least 99% of the total polyphenol pool measured in plasma and urine. Third, we determined the association between aronia polyphenol metabolites and changes in key biomarkers of CVD risk in an intervention study. Former smokers, which were at greater risk for CVD, consumed aronia berry extract for 12 wk. Aronia consumption reduced fasting plasma total cholesterol (TC) level by 8% during the 12-week treatment compared with placebo group, and reduced plasma LDL-C level by 7% and 11% at both 6 wks and 12 wks compared with placebo group. In addition, participants in the aronia group who showed the largest decreases in TC had stronger correlations of urinary peonidin-3-O-galactoside and cyanidin-3-O-galactoside than those who did not respond to the intervention. Thus, this study demonstrated that the cholesterol-lowering activity of polyphenol rich foods is associated in-part with its tissue metabolites.

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