Four-Week Strawberry Consumption on Selected (Poly)phenolic Metabolites: A Randomized Controlled Trial in Older Adults With Moderate Hypercholesterolemia

Abstract

Abstract Objectives Strawberries are a rich source of bioactive (poly)phenols, such as anthocyanins, ellagitannins and proanthocyanidins, which are absorbed and metabolized to various (poly)phenolic metabolites in the human body. Phenolic acids metabolites have been characterized and reported previously. This study aimed to investigate the presence of anthocyanin, urolithin and phenyl-γ-valerolactone metabolites present in circulation after 4-week strawberry consumption in older adults with moderate hypercholesterolemia. Methods This research was performed using blood samples from a randomized, controlled, double-blinded, 2-arm, 2-period (4-week/period) crossover trial. Adults (n = 33, male: female 16:17, age 53 ± 1 years, body mass index 31 ± 1 kg/m2, mean ± SEM) were randomized to 1 of 2 study sequences. Subjects drank study beverages twice-daily containing freeze-dried strawberry powder (2 × 25 g) or energy-, volume-matched control powder for 4 weeks separated by a 4-week washout. Fasting plasma samples after each intervention were quantified for (poly)phenolic metabolites using an ultra-high performance liquid chromatography coupled with triple quadrupole (UHPLC-QQQ). Statistical analysis was performed using PC-SAS. Results Four-week strawberry beverage vs. control beverage intake significantly increased fasting plasma concentrations of pelargonidin 3-O-glucoside (0.2 ± 0.03 nmol/L vs. 0 ± 0 nmol/L, P < 0.0001), pelargonidin glucuronide (3.8 ± 0.9 nmol/L vs. 0 ± 0 nmol/L, P < 0.0001), 8-hydroxy-urolithin-glucuronide (urolithin A-3-glucuronide, 70.1 ± 18.1 nmol/L vs. 0.3 ± 0.3 nmol/L, P = 0.0001), phenyl-γ-valerolactone-glucuronide (4.4 ± 1.1 nmol/L vs. 0 ± 0 nmol/L, P = 0.0001), and hydroxyphenyl-γ-valerolactone-glucuronide (3.5 ± 0.9 nmol/L vs. 1.1 ± 0.4 nmol/L, P = 0.009). Conclusions Strawberry (poly)phenols are absorbed and metabolized and can persist in the circulation with daily intake. The persistent concentration of selected (poly)phenolic metabolites in older adults with moderate hypercholesterolemia warrant further research to determine their potential health benefits. Funding Sources This project was funded by the California Strawberry Commission and various donor funds to the Center for Nutrition Research, Illinois Institute of Technology.