High phenolics Rutgers Scarlet Lettuce improves glucose metabolism in high fat diet‐induced obese mice

Abstract

Scope The ability of high phenolic Rutgers Scarlet Lettuce (RSL) to attenuate metabolic syndrome and gut dysbiosis was studied in very high fat diet (VHFD)-fed mice. Phenolic absorption was assessed in vivo and in a gastrointestinal tract model. Methods and results Mice were fed VHFD, VHFD supplemented with RSL (RSL-VHFD) or store-purchased green lettuce (GL-VHFD), or low-fat diet (LFD) for 13 weeks. Compared to VHFD or GL-VHFD-fed groups, RSL-VHFD group showed significantly improved oral glucose tolerance (p<0.05). Comparison of VHFD, RSL-VHFD, and GL-VHFD groups revealed no significant differences with respect to insulin tolerance, hepatic lipids, body weight gain, fat mass, plasma glucose, triglycerides, free fatty acid, and lipopolysaccharide levels, as well as relative abundances of major bacterial phyla from 16S rDNA amplicon data sequences (from fecal and cecal samples). However, RSL and GL-supplementation increased abundance of several taxa involved in plant polysaccharide degradation/fermentation. RSL phenolics chlorogenic acid, quercetin-3-glucoside, and quercetin-malonyl-glucoside were bioaccessible in the TIM-1 digestion model, but had relatively low recovery. Conclusions RSL phenolics contributed to attenuation of postprandial hyperglycemia. Changes in gut microbiota were likely due to microbiota accessible carbohydrates in RSL and GL rather than RSL phenolics, which may be metabolized, absorbed, or degraded before reaching the colon.

Grape proanthocyanidin-induced intestinal bloom of Akkermansia muciniphila is dependent on its baseline abundance and precedes activation of host genes related to metabolic health

“…As the most abundant class of polyphenols, we hypothesized that PACs, which are concentrated in seeds and skin, could be sufficient to induce a bloom in A. muciniphila . This was bolstered by our previous finding of no Akkermansia bloom with a high-polyphenol lettuce variety that did not contain PACs [13], as well as evidence of an Akkermansia bloom with cranberry extract rich in PAC [12] and apple PAC [10]. We therefore compared the ability of GPE or a standard of purified oligomeric PACs from grape seeds (PAC standard) to promote the intestinal bloom of A. muciniphila in a 10-day dosing study.…”

“…Major compounds contained in grape berries, cranberries, and apples include flavan-3-ols (catechins and epicatechin), proanthocyanidins (PAC; polymers of flavan-3-ols), anthocyanin pigments, flavonols, and phenolic acids [11, 12]. Mice fed HFD supplemented with a polyphenol-rich red lettuce variety rich in chlorogenic acid, anthocyanins, and flavonols, but undetectable levels of PAC, demonstrated improved oral glucose tolerance after 9 weeks of supplementation, but did not show a bloom in A. muciniphila after 12 weeks [13] further suggesting that PAC may be the compounds responsible for the GP-induced bloom. Here we investigated the timing of the GP-induced A. muciniphila bloom and identify the polyphenol class sufficient to promote this effect.…”

Fiber Supplements Derived From Sugarcane Stem, Wheat Dextrin and Psyllium Husk Have Different In Vitro Effects on the Human Gut Microbiota

“…Dietary polyphenols and antioxidants have also been studied for their ability to beneficially change gut microbial composition and functions (Hervert-Hernández and Goñi, 2011 ; Cheng et al, 2016 ) and therefore also have prebiotic potential. Polyphenols from various fruits and tea have been shown to inhibit the growth of pathogens and maintain the growth of Lactobacillus, Bifidobacterium, Lachnospiraceae , and Eubacterium rectale (Hervert-Hernández and Goñi, 2011 ; Sheflin et al, 2016 ).…”

The Alternate Consumption of Quercetin and Alliin in the Traditional Asian Diet Reshaped Microbiota and Altered Gene Expression of Colonic Epithelial Cells in Rats

“…The rats in Group Alt had the highest average body weight ( P < 0.05), followed by those in Group Que ( P > 0.05; Table ). Limited effect of quercetin on body weight had been demonstrated in a previous report that showed quercetin lacked anti‐obesity effect unless the treatment periods were longer than 9 weeks (Cheng et al., ). In addition, the intake of quercetin in high‐fat sucrose diet‐fed rats could hardly reduce the body weight gain as a similar result was obtained in the treatment and the control group (Etxeberria et al., ).…”