Effects of Extrinsic Wheat Fiber Supplementation on Fecal Weight; A Randomized Controlled Trial

Abstract

Higher fiber intake may confer beneficial effects on health. Our objective was to investigate the impact of 10 g extrinsic wheat fiber on fecal bulk. Therefore, we performed two randomized intervention studies in which we provided extrinsic wheat fiber-enriched products or appropriate control products for five days together with normal diet. In one trial, 10 participants received fiber-enriched food products, whereas in the second study, 19 participants supplemented their daily diet with fiber-enriched drinks. The main outcome variable of this intervention was fecal bulk. Other outcomes were gut microbiota composition, short chain fatty acids in feces, and stool consistency and frequency. Fecal wet weight was significantly increased (p < 0.02) with extrinsic wheat fiber-enriched foods. In contrast, ingestion of extrinsic wheat fiber in the form of drinks did not significantly change fecal wet weight. In both groups, fecal dry weight was not altered upon extrinsic wheat fiber supplementation. However, the intake of fiber-enriched foods resulted in higher acetic acid levels in feces compared to fiber-enriched drinks. Regarding gut microbiota profiles, extrinsic wheat fiber-enriched food products were not associated with substantial alterations. In conclusion, 10 g extrinsic wheat fiber added to a normal diet increased fecal bulk if administered in a solid food matrix, but not if applied in the form of drinks. DRKS, DRKS00015792.Registered 30 October 2018.

Effects of Dietary Fibers on Short-Chain Fatty Acids and Gut Microbiota Composition in Healthy Adults: A Systematic Review

“…As for the individual SCFAs, a total of 26 studies showed no overall significant differences [9,10,12,14,[16][17][18][19][20][21][23][24][25]27,28,[32][33][34][35][36]38,39,43,[47][48][49]. Two studies [40,42] reported a significant increase in acetate, butyrate, and propionate, while another two reported a significant decrease for all three SCFAs [11,13].…”

“…The main characteristics of the 42 included studies are reported in Table S1. A total of 44 trials were available for detailed analysis from the 42 included studies since two of the publications [9,10] reported two separate trials. Specifically, 10 out of the 44 trials were parallel randomized controlled trials (RCTs), while 34 were cross-over RCTs.…”

“…The other fibers used were: arabinogalactan [24], xylo-oligosaccharide (XOS) [25] IN + XOS [22], beta-glucans [26], digestion-resistant dextrin [27], extrinsic wheat fiber [9], resistant starch (RS) [28][29][30] , AXOS + RS + glucans [31], galacto-oligosaccharides (GOS) [32], L-rhamonse (L-Rha) [17], polydextrose (PDX) [11,13,33,34], oligofructose (OF) [35,36], raffinose [12], soluble fiber [11,13] , wheat bran extract (WBE) [36][37][38], 2′fucosyllactose (FL), lacto-N-neotetraose (LNnT), 2′FL + LNnT [39], lupin kernel fiber, and citrus fiber [40].…”

“…Concerning the techniques used for the evaluation of SCFAs, the most widely used was gas chromatography (GC) (22 trials); the remaining trials used: gas chromatographymass spectrometry (GC-MS) [24,26,29,35,36,45] high-performance liquid chromatography (HPLC) [16,23,32,39,47,48], capillary gas-liquid chromatography (GLC) [15,22,25], gas chromatography-flame ionization detection (GC-FID) [40], liquid chromatography-tandem mass spectrometry (LC-MS/MS) [9], nuclear magnetic resonance (NMR) [34,44], ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) [49], and ion exchange chromatography with conductivity detection [38]. Considering the different accuracy and reliability of the obtainable results, the technique used must be properly considered in the assessment of the data obtained.…”

“…The effects of DF supplementation on the SCFA profile were strictly dependent on dose [18,25,29,31,37] and on the type and structure of DFs [9,11,13,18,22,26,29,31,40,50]. In addition, few studies reported that the effects could be influenced by individual factors such as age [28] and gender [26].…”