Search results

(1 - 2 of 2)
THE RECIPROCAL INTERACTIONS BETWEEN RED RASPBERRY POLYPHENOLS AND GUT MICROBIOME COMPOSITION: PRELIMINARY FINDINGS
Title
THE RECIPROCAL INTERACTIONS BETWEEN RED RASPBERRY POLYPHENOLS AND GUT MICROBIOME COMPOSITION: PRELIMINARY FINDINGS
Creator
Zhang, Xuhuiqun
Date
2017, 2017-07
Description
Red raspberry (Rubus idaeus L.) contains a variety of polyphenols including anthocyanins and ellagitannins. Red raspberry polyphenols absorbed...
Show moreRed raspberry (Rubus idaeus L.) contains a variety of polyphenols including anthocyanins and ellagitannins. Red raspberry polyphenols absorbed in different forms (parent compounds, degradant or microbial metabolite molecules) are subject to xenobiotic metabolism in the intestine, liver, and/or kidney, forming methylate, glucuronide, and sulfate conjugated metabolites. Consistent exposure of certain polyphenols to the gut microbiota may act as prebiotic-like substances feeding the beneficial gut bacteria and changing the gut microbiome composition and function. The dichotomy between the biotransformation of polyphenols into their metabolites by gut microbiota and the modulation of gut microbiome composition by polyphenols is hypothesized to contribute to positive health outcomes. The present study examined the regular consumption of red raspberry purée (RRB) and/or fructo-oligosaccharide (FOS) on gut microbiome composition and subsequent bioavailability of red raspberry polyphenols in healthy volunteers. An 8-week pilot study, including two 4-week chronic treatments and 3 postprandial days, served as a feasibility study and mechanism to collect multiple biological specimens for method development. An ultra high-performance liquid chromatography (HPLC) coupled with electrospray ionization quadrupole time of flight (QTOF) and triple quadrupole (QQQ) mass spectrometer were used to identify and quantify the phenolic compounds in red raspberry purée, plasma and urine samples. Fecal samples were used for the metagenomic study. The sequencing of the 16S ribosomal RNA gene was utilized to study the gut microbiome composition. The red raspberry purée contained 148.55 ± 5.43 mg/100 g fresh weight (FW) polyphenols. Chronic RRB and/or FOS exposure influenced gut microbiome composition: at the phylum level, 4-week FOS (8 g/d), RRB (125 g/d), or FOS plus RRB (8 and 125 g/d, respectively) exposures all decreased Firmicutes and increased Bacteroidetes; at the genus level, 4-week FOS, RRB, or FOS plus RRB exposures all boosted Bacteroides and diminished Blautia; and the increased Akkermansia was only observed after RRB exposure. Chronic RRB and/or FOS exposure also altered the observed RRB polyphenol metabolites: the parent anthocyanins, such as cyanidin 3-O-sophoroside, were lower in plasma and urine after adaptation to RRB, while the production of urolithin A glucuronide (the main microbial-derived metabolite of ellagitannins) increased after FOS, RRB and FOS plus RRB exposure; an effect hypothesized to be related to the altered composition and metabolic activity of the gut microbiota. Overall, these data suggest chronic RRB and/or FOS exposure influenced gut microbiome composition and subsequently increased gut microbial metabolites.
M.S. in Food Safety and Technology, July 2017
Show less
RECIPROCAL INTERACTIONS BETWEEN RED RASPBERRY POLYPHENOLS AND GUT MICROBIOME COMPOSITION AND METABOLIC HEALTH
Title
RECIPROCAL INTERACTIONS BETWEEN RED RASPBERRY POLYPHENOLS AND GUT MICROBIOME COMPOSITION AND METABOLIC HEALTH
Creator
Zhang, Xuhuiqun
Date
2020
Description
Red raspberries (RRB) and fructo-oligosaccharides (FOS) have been associated with reduced risk of developing cardio-metabolic diseases. RRB...
Show moreRed raspberries (RRB) and fructo-oligosaccharides (FOS) have been associated with reduced risk of developing cardio-metabolic diseases. RRB are uniquely high in anthocyanin- and ellagitannin- type (poly)phenols, however, these (poly)phenols have low bioavailability. Gut microbiota can improve (poly)phenol bioavailability through fermentation processes generating absorbable metabolites and altering gut microbiota structure. However, clinical evidence on the effects of RRB intake on the gut microbiome, (poly)phenolic metabolites and metabolic health is lacking. Further, fermentable carbohydrates (FOS) that selectively stimulate gut microbiota growth may enhance metabolite generation. Therefore, the aim of this research is to investigate the interactions between the gut microbiome and RRB, and explore added effects of FOS as a possible nutritional strategy for improving metabolic health of at risk individuals with prediabetes and insulin resistance (PreDM-IR). Through a series of investigations drawn from a randomized clinical trial (RCT), the following hypotheses were tested: 1) Individuals with PreDM-IR will have a distinctive gut microbiome, and lower capacity to metabolize (poly)phenols compared to healthy individuals; 2) RRB intake for 4-week will increase microbial-derived (poly)phenolic metabolites and adding FOS will augment the effect; 3) RRB intake will improve metabolic risk factors in PreDM-IR and adding FOS will augment the RRB effect; 4) RRB and RRB+FOS supplementations will alter the structure of the gut microbiome explaining variances observed in metabolites and metabolic outcomes. In this single-blinded, crossover RCT, adults with PreDM-IR (n=26) and a healthy group (n=10) consumed 1 cup RRB (fresh weight equivalence) per day or RRB with 8g FOS per day for 4 weeks in random order separated by 4-week washout. Metabolic risk factors, (poly)phenolic metabolites and metagenomic profile were assessed before and after supplementation. Baseline characterization before supplementation revealed distinctive metabolites and metagenomics profiles related to metabolic status. After 4-week RRB, microbial (poly)phenolic metabolites, metabolic health indices and gut microbiome structure beneficially shifted in PreDM-IR group. Adding FOS increased specific microbial species and phenolic metabolites that correlated with β-cell function in PreDM-IR. Overall, nutritional strategies incorporating RRB and FOS may improve metabolic health of individuals with PreDM-IR through modulating gut microbiome composition and the capacity to metabolize RRB (poly)phenols.
Show less