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Session: Polyphenols: Metabolism and Health (Oral 18)

(OR18-02-24) Essential Role of Gut Microbiome in Determining Circulating Levels of Blueberry Polyphenol Metabolite Exposure

Monday, July 1, 2024
8:12 AM – 8:24 AM CT
Location:  W183
ELPC
Objectives: This study investigated the role of the gut microbiome in determining exposure to blueberry polyphenol metabolites using germ-free mice and those colonized with fecal microbiomes collected from humans that participated in a 12-week blueberry feeding intervention.

Methods: Fecal samples were collected from postmenopausal women with above-normal blood pressure before (Pre-BB) and after 12 weeks of blueberry consumption (Post-BB), or 12 weeks post-placebo consumption (Post-PL). Pooled samples were used to colonize 6-week-old germ-free (GF) male C57BL/6 mice, while a control group remained germ-free (total n = 24, n = 6/group). Six weeks after gut microbiota colonization, mice were gavaged with 116.1 mg of freeze-dried blueberry powder, and blood was collected after 1 and 6 hours. Plasma polyphenol metabolites were analyzed using microelution solid-phase extraction coupled with liquid chromatography-mass spectrometry.

Results: At 1 hour, gut microbial metabolite 4-methylcatechol-1-sulfate was higher in colonized mice compared to GF mice (p = p < 0.05). At 6 hours, several gut microbial metabolites (e.g., 4-methylcatechol-1-sulfate, hippuric acid, 2,5-dihydroxybenzoic acid, hydroxyphenyllactic acid, isovanillic acid 3-O-sulfate, dihydro caffeic acid 3-O-sulfate, and isoferulic acid 3-O-sulfate) were higher (p < 0.05) in colonized mice than GF mice. However, at 6 hours, several parent anthocyanins (i.e., malvidin 3-arabinoside, -galactoside, and -glucoside, peonidin 3-galactoside) were higher in GF mice than Post-BB and Post-PL groups (p < 0.05), as well as other compounds present in blueberries (e.g., chlorogenic acid, 3-feruloylquinic acid), which were higher (p < 0.05) in GF mice than in all colonized mice.

Conclusions: These data identify which polyphenol metabolites result from gut microbiome metabolism and are critical for identifying how these microbes influence blueberry polyphenol metabolite exposure. Next steps include evaluation of chronic blueberry consumption on gut microbial polyphenol metabolizing capacity and understanding the role of these metabolites in improving endothelial function and predicting individual responses to blueberry polyphenol intake.

Funding Sources: USDA National Institute of Food and Agriculture [grant no. 2020-67017-30833/project accession no.1021875] and the US Highbush Blueberry Council.