Bioavailability and pharmacokinetics of (poly)phenols following consumption of selected blueberries and a blueberry-rich protein bar by adult males and females: a randomized, crossover, controlled trial.

Abstract

Background: It's commonly believed that higher nutrient content equates to healthier foods, and food processing lowers nutrient content, although bioavailability studies often indicate otherwise. Blueberries, a rich source of (poly)phenols with proven health benefits, provide a feasible model to evaluate phytochemical bioavailability following consumption of raw and processed fruits.

Objective: This study evaluates the effect of processing on the bioavailability of (poly)phenols following consumption of 4 interventions: 2 blueberry varieties (i.e., Elliott and Olympia) selected based on differing (poly)phenol content and in vitro bioaccessibility, a (poly)phenol-rich protein bar providing an equivalent amount of blueberries, and a control beverage.

Methods: This blinded, randomized, 4-way crossover, controlled trial (n = 18; 42.06±12.53 y; BMI 24.75±2.97 kg/m²) fed one serving (150 g) of Elliott and Olympia blueberries and a (poly)phenol-rich protein bar containing one serving of Elliott blueberries, compared to a macronutrient-matched control beverage. (Poly)phenols and metabolites were analyzed in blood and urine over 48h, with bioavailability and pharmacokinetics assessed via linear mixed-effects repeated measures ANOVA.

Results: Recovery of metabolites was similar following consumption of blueberry varieties of differing (poly)phenol composition, with higher total urinary recovery after Elliott blueberry relative to Olympia blueberry and protein bar (21% and 29%, respectively). Serum area under the curve was similar across berry-derived treatments, while differences in maximum concentration (C_max) and time at maximum concentration (T_max) were observed; for example, urinary recovery of 3-methoxycinnamic acid-4-O-glucuronide was similar following Elliott blueberry and protein bar (p=1.00), while C_max was 1.24 h later after Elliott blueberry vs protein bar (T_max=3.84 vs 2.60 h). Alternatively, C_max for 3-(3-hydroxyphenyl)propanoic acid was higher following Elliott blueberry vs Olympia blueberry and protein bar (26.63 and 25.32 ng/mL, respectively).

Conclusion: Differing berry (poly)phenol content and bioaccessibility only minimally affected bioavailability following consumption of blueberries relative to a blueberry-rich protein bar, suggesting (poly)phenol-dense foods, such as bars and snacks, could provide similar health benefits as raw fruits. Further studies using other crops are required to assess if these findings are translatable.

Clinical trial registry: NCT04175106 (https://clinicaltrials.gov/ct2/show/NCT04175106?term=19138&draw=2&rank=1) CLINICAL TRIAL REGISTRY: NCT04175106 (https://clinicaltrials.gov/study/NCT04175106).