A Crossover Study of Freeze-Dried Strawberry Powder on Microvascular Function, Gut Microbiota, and Metabolic Phenotype in Overweight or Obese Postmenopausal Women

Abstract

Abstract Objectives To assess the short-term intake of 39 g freeze-dried strawberry powder (FDSP), compared to an isocaloric control powder, on microvascular function and to determine the relationship with gut microbial composition and select microbial-derived metabolites from feces, serum, and urine. Methods Data were collected from overweight/obese postmenopausal women (n = 21) participating in a 2 × 2 double-blind, placebo-controlled crossover study. Participants consumed FDSP or control, mixed with water, daily for 4 weeks (separated by a 4-week washout). Microvascular function was evaluated as the Framingham reactive hyperemia index (fRHI). Serum, urine, and fecal metabolomics were performed by proton Nuclear Magnetic Resonance (1H NMR) spectroscopy, microbiome analysis was performed by targeting the v4 region of the 16S rRNA gene. Additional measures included anthropometrics, fasting plasma lipids, glucose, and blood pressure, and the urolithin metabotype of study participants was determined by LC-MS. Results Overall, 19 women completed the protocol; with two additional women completing at least one arm of the study. Linear mixed effects modelling revealed no significant intervention effects on the primary endpoint or on other vascular measures. However, significant period effects were observed for fRHI. FDSP significantly increased serum and urine ascorbate concentrations (P < 0.05) and altered the concentration of several other metabolites, including serum acetate, alanine, dimethyl sulfone, and proline, and urine citrate, formate, glycine, alanine, and 3-hydroxybutyrate. Finally, FDSP intake shifted bacterial genera in the gut microbiome, primarily by increasing populations of Faecalibacterium, Dialister, Ruminococcus, and Lachnospira. Conclusions This study demonstrates that although short-term daily intake of FDSP does not appear to influence microvascular function in postmenopausal women with elevated CVD risk, there are measurable shifts in metabolism and the microbiome. Funding Sources This work was funded by a grant awarded by the California Strawberry Commission, and USDA-NIFA Hatch grants awarded to CLK (CA-D-NTR-5908-H) and CMS (project 1,021,411).