Strawberry Consumption, Cardiometabolic Risk Factors, and Vascular Function: A Randomized Controlled Trial in Adults with Moderate Hypercholesterolemia

Abstract

Background: Certain fruits, such as strawberries, may impart cardiometabolic benefits due to their phytochemical content.

Objectives: Study aims were to assess the effects of strawberry intake on cardiometabolic risk factors and vascular endothelial function in adults with moderate hypercholesterolemia.

Methods: This study was a randomized, controlled, double-blinded, 2-arm, 2-period (4-wk/period) crossover trial. Adults (n = 34; male/female 1:1; mean ± SEM age, 53 ± 1 y; BMI, 31 ± 1 kg/m2; LDL cholesterol, 133 ± 3 mg/dL) were randomly allocated to 1 of 2 study sequences in a 1:1 ratio. Participants drank study beverages twice daily containing freeze-dried strawberry powder (2 × 25 g) or energy-, volume-matched control powder for 4 wk separated by a 4-wk washout. The primary outcome variable was the difference in fasting LDL cholesterol after 4-wk interventions. Secondary outcomes were metabolic markers, inflammation, quantitative (poly)phenolic metabolomics, flow-mediated dilation (FMD), and blood pressure (BP), with the latter (FMD, BP) also assessed acutely at 1 h and 2 h after a 50-g bolus strawberry or control beverage. Mixed-model analysis of repeated measures via PROC MIXED, PC-SAS was performed on primary and secondary outcome variables.

Results: LDL cholesterol did not differ after the 4-wk interventions (P > 0.05), nor did fasting total cholesterol, triglycerides, glucose, insulin, high-sensitivity C-reactive protein, FMD, or BP (all P > 0.05). Significant intervention-by-hour interaction for FMD (P = 0.03) and BP (P = 0.05) revealed increased FMD at 1 h after strawberry compared with control by 1.5 ± 0.38% (P = 0.0008) and attenuated systolic BP at 2 h by 3.1 ± 0.99 mmHg (P = 0.02). Select phenolic metabolites increased significantly (P < 0.05) in blood following strawberry consumption while others decreased, including 3-(4-methoxyphenyl)propanoic acid-3-O-glucuronide, which was significantly correlated with increased FMD (P < 0.05).

Conclusion: Strawberries may improve vascular health, independent of other metabolic changes. The effect may be related to changes in microbial-derived phenolic metabolites after strawberry consumption influencing endothelial function. Data support inclusion of strawberries in a heart-healthy diet in adults with moderate hypercholesterolemia.This trial was registered at clinicaltrials.gov as NCT02612090.

Keywords: (poly)phenolic metabolites; cardiovascular risk factors; flow-mediated dilation; hypercholesterolemia; strawberry.