0
selected
-
1.
Fecal microbial transplantation and fiber supplementation in patients with severe obesity and metabolic syndrome: a randomized double-blind, placebo-controlled phase 2 trial.
Mocanu, V, Zhang, Z, Deehan, EC, Kao, DH, Hotte, N, Karmali, S, Birch, DW, Samarasinghe, KK, Walter, J, Madsen, KL
Nature medicine. 2021;(7):1272-1279
Abstract
Fecal microbial transplantation (FMT) from lean donors to patients with obesity has been associated with metabolic benefits, yet results so far have been inconsistent. In this study, we tested the application of daily fiber supplementation as an adjunct to FMT therapy to modulate cardiometabolic outcomes. We performed a double-blind randomized trial in patients with severe obesity and metabolic syndrome receiving oral FMT, to test high-fermentable (HF) and low-fermentable (LF) fiber supplements (NCT03477916). Seventy participants were randomized to the FMT-HF (n = 17), FMT-LF (n = 17), HF (n = 17) and LF (n = 19) groups. The primary outcome was the assessment of change in insulin sensitivity from baseline to 6 weeks using the homeostatic model assessment (HOMA2-IR/IS). After 6 weeks, only patients in the FMT-LF group had significant improvements in HOMA2-IR (3.16 ± 3.01 at 6 weeks versus 3.77 ± 3.57 at baseline; P = 0.02). No difference in HOMA2-IR was observed over this period for those in the FMT-HF group (3.25 ± 1.70 at 6 weeks versus 3.17 ± 1.72 at baseline; P = 0.8), the HF group (3.49 ± 1.43 at 6 weeks versus 3.26 ± 1.33 at baseline; P = 0.8) or the LF group (3.76 ± 2.01 at 6 weeks versus 3.56 ± 1.81 at baseline; P = 0.8). Interventions were safe and well-tolerated with no treatment-attributed serious adverse events. We provide proof of concept for the use of a single-dose oral FMT combined with daily low-fermentable fiber supplementation to improve insulin sensitivity in patients with severe obesity and metabolic syndrome.
-
2.
Precision Microbiome Modulation with Discrete Dietary Fiber Structures Directs Short-Chain Fatty Acid Production.
Deehan, EC, Yang, C, Perez-Muñoz, ME, Nguyen, NK, Cheng, CC, Triador, L, Zhang, Z, Bakal, JA, Walter, J
Cell host & microbe. 2020;(3):389-404.e6
Abstract
Dietary fibers (DFs) impact the gut microbiome in ways often considered beneficial. However, it is unknown if precise and predictable manipulations of the gut microbiota, and especially its metabolic activity, can be achieved through DFs with discrete chemical structures. Using a dose-response trial with three type-IV resistant starches (RS4s) in healthy humans, we found that crystalline and phosphate cross-linked starch structures induce divergent and highly specific effects on microbiome composition that are linked to directed shifts in the output of either propionate or butyrate. The dominant RS4-induced effects were remarkably consistent within treatment groups, dose-dependent plateauing at 35 g/day, and can be explained by substrate-specific binding and utilization of the RS4s by bacterial taxa with different pathways for starch metabolism. Overall, these findings support the potential of using discrete DF structures to achieve targeted manipulations of the gut microbiome and its metabolic functions relevant to health.
-
3.
Single-component versus multicomponent dietary goals for the metabolic syndrome: a randomized trial.
Ma, Y, Olendzki, BC, Wang, J, Persuitte, GM, Li, W, Fang, H, Merriam, PA, Wedick, NM, Ockene, IS, Culver, AL, et al
Annals of internal medicine. 2015;(4):248-57
-
-
Free full text
-
Abstract
BACKGROUND Few studies have compared diets to determine whether a program focused on 1 dietary change results in collateral effects on other untargeted healthy diet components. OBJECTIVE To evaluate a diet focused on increased fiber consumption versus the multicomponent American Heart Association (AHA) dietary guidelines. DESIGN Randomized, controlled trial from June 2009 to January 2014. (ClinicalTrials.gov: NCT00911885). SETTING Worcester, Massachusetts. PARTICIPANTS 240 adults with the metabolic syndrome. INTERVENTION Participants engaged in individual and group sessions. MEASUREMENTS Primary outcome was weight change at 12 months. RESULTS At 12 months, mean change in weight was -2.1 kg (95% CI, -2.9 to -1.3 kg) in the high-fiber diet group versus -2.7 kg (CI, -3.5 to -2.0 kg) in the AHA diet group. The mean between-group difference was 0.6 kg (CI, -0.5 to 1.7 kg). During the trial, 12 (9.9%) and 15 (12.6%) participants dropped out of the high-fiber and AHA diet groups, respectively (P = 0.55). Eight participants developed diabetes (hemoglobin A1c level ≥6.5%) during the trial: 7 in the high-fiber diet group and 1 in the AHA diet group (P = 0.066). LIMITATIONS Generalizability is unknown. Maintenance of weight loss after cessation of group sessions at 12 months was not assessed. Definitive conclusions cannot be made about dietary equivalence because the study was powered for superiority. CONCLUSION The more complex AHA diet may result in up to 1.7 kg more weight loss; however, a simplified approach to weight reduction emphasizing only increased fiber intake may be a reasonable alternative for persons with difficulty adhering to more complicated diet regimens. PRIMARY FUNDING SOURCE National Heart, Lung, and Blood Institute.
-
4.
Dietary fiber intake reduces risk for gastric cancer: a meta-analysis.
Zhang, Z, Xu, G, Ma, M, Yang, J, Liu, X
Gastroenterology. 2013;(1):113-120.e3
Abstract
BACKGROUND & AIMS The association between dietary fiber intake and gastric cancer risk has been investigated by many studies, with inconclusive results. We conducted a meta-analysis of case-control and cohort studies to analyze this association. METHODS Relevant studies were identified by searching PubMed and Embase through October 2012. We analyzed 21 articles, which included 580,064 subjects. Random-effects models were used to estimate summary relative risks. Dose-response, subgroup, sensitivity, meta-regression, and publication bias analyses were performed. RESULTS The summary odds ratios of gastric cancer for the highest, compared with the lowest, dietary fiber intake was 0.58 (95% confidence interval, 0.49-0.67) with significant heterogeneity among studies (P < .001, I(2) = 62.2%). Stratified analysis for study design, geographic area, source and type of fiber, Lauren's classification, publication year, sample size, and quality score of study yielded consistent results. Dose-response analysis associated a 10-g/day increment in fiber intake with a significant (44%) reduction in gastric cancer risk. Sensitivity analysis restricted to studies with control for conventional risk factors produced similar results, and omission of any single study had little effect on the combined risk estimate. CONCLUSIONS In a meta-analysis, we show that dietary fiber intake is associated inversely with gastric cancer risk; the effect probably is independent of conventional risk factors. The direction of the protective association of dietary fiber was consistent among all studies, but the absolute magnitude was less certain because of heterogeneity among the studies. Further studies therefore are required to establish this association.