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1.
Dietary Fibre Modulates the Gut Microbiota.
Cronin, P, Joyce, SA, O'Toole, PW, O'Connor, EM
Nutrients. 2021;(5)
Abstract
Dietary fibre has long been established as a nutritionally important, health-promoting food ingredient. Modern dietary practices have seen a significant reduction in fibre consumption compared with ancestral habits. This is related to the emergence of low-fibre "Western diets" associated with industrialised nations, and is linked to an increased prevalence of gut diseases such as inflammatory bowel disease, obesity, type II diabetes mellitus and metabolic syndrome. The characteristic metabolic parameters of these individuals include insulin resistance, high fasting and postprandial glucose, as well as high plasma cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL). Gut microbial signatures are also altered significantly in these cohorts, suggesting a causative link between diet, microbes and disease. Dietary fibre consumption has been hypothesised to reverse these changes through microbial fermentation and the subsequent production of short-chain fatty acids (SCFA), which improves glucose and lipid parameters in individuals who harbour diseases associated with dysfunctional metabolism. This review article examines how different types of dietary fibre can differentially alter glucose and lipid metabolism through changes in gut microbiota composition and function.
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2.
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.
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3.
Effect of soluble-viscous dietary fibre on coronary heart disease risk score across 3 population health categories: data from randomized, double-blind, placebo-controlled trials.
Vuksan, V, Sievenpiper, JL, Jovanovski, E, Jenkins, AL, Komishon, A, Au-Yeung, F, Zurbau, A, Ho, HVT, Li, D, Smircic-Duvnjak, L
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. 2020;(7):801-804
Abstract
We applied the Framingham risk equation in healthy, metabolic syndrome, and diabetes populations, following treatment with viscous fibre from konjac-based blend (KBB). KBB yielded reduction in estimated risk score by 16% (1.04 ± 0.03 vs. 0.87 ± 0.04, p < 0.01) in type 2 diabetes, 24% (1.08 ± 0.01 vs. 0.82 ± 0.02, p < 0.01) in metabolic syndrome, and 25% (1.09 ± 0.05 vs. 0.82 ± 0.06, p < 0.01) in healthy individuals. Drivers for decreased risk were improvements in blood cholesterol and systolic blood pressure. The composite coronary heart disease risk across populations was reduced 22% (p < 0.01). Novelty Viscous fibre from konjac-xanthan reduced 10-year relative coronary heart disease using Framingham Risk Score across the glycemic status spectrum.
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4.
Can dietary viscous fiber affect body weight independently of an energy-restrictive diet? A systematic review and meta-analysis of randomized controlled trials.
Jovanovski, E, Mazhar, N, Komishon, A, Khayyat, R, Li, D, Blanco Mejia, S, Khan, T, L Jenkins, A, Smircic-Duvnjak, L, L Sievenpiper, J, et al
The American journal of clinical nutrition. 2020;(2):471-485
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Abstract
BACKGROUND The role of dietary fiber in obesity management remains debatable. Evidence suggests that intake of viscous fiber may have the potential to facilitate weight loss. OBJECTIVE We aimed to summarize and quantify the effects of viscous fiber on body weight, BMI, waist circumference, and body fat, independent of calorie restriction, through a systematic review and meta-analysis of randomized controlled trials. METHODS Trials ≥4 wk in duration that assessed the effect of viscous fiber supplemented to an ad libitum diet along with comparator diets were included. MEDLINE, EMBASE, and the Cochrane library were searched through 24 July, 2019. Two independent reviewers extracted relevant data. Data were pooled using the generic inverse variance method and random-effects models and expressed as mean differences with 95% CIs. Interstudy heterogeneity was assessed (Cochran Q statistic) and quantified (I2 statistic). The overall certainty of evidence was explored using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. RESULTS Findings from 62 trials (n = 3877) showed that viscous fiber reduced mean body weight (-0.33 kg; 95% CI: -0.51, -0.14 kg; P = 0.004), BMI (in kg/m2) (-0.28; 95% CI: -0.42, -0.14; P = 0.0001), and waist circumference (-0.63 cm; 95% CI: -1.11, -0.16 cm; P = 0.008), with no change in body fat (-0.78%; 95% CI: -1.56%, 0.00%; P = 0.05) when consumed with an ad libitum diet. Greater reductions in body weight were observed in overweight individuals and those with diabetes and metabolic syndrome. The certainty of evidence was graded moderate for body weight, high for waist circumference and body fat, and low for BMI. CONCLUSIONS Dietary viscous fiber modestly yet significantly improved body weight and other parameters of adiposity independently of calorie restriction. Future trials are warranted to address the inconsistency and imprecision identified through GRADE and to determine long-term weight-loss sustainability.This systematic review and meta-analysis was registered at clinicaltrials.gov as NCT03257449.
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Flaxseed for Health and Disease: Review of Clinical Trials.
Shayan, M, Kamalian, S, Sahebkar, A, Tayarani-Najaran, Z
Combinatorial chemistry & high throughput screening. 2020;(8):699-722
Abstract
BACKGROUND Flaxseed (Linum usitatissimum) is an oil-based seed that contains high amounts of alpha-linolenic acid, linoleic acid, lignans, fiber and many other bioactive components which is suggested for a healthier life. Nowadays, flaxseed is known as a remarkable functional food with different health benefits for humans and protects against cardiovascular disease, diabetes, dyslipidemia, obesity and altogether metabolic syndrome. METHODS To review the bioactive components of flaxseed and their potential health effects, PubMed and Scopus were searched from commencement to July 2019. Keywords including: "flaxseed", "Linum usitatissimum", "metabolic syndrome", "obesity", "inflammation", "insulin resistance", "diabetes", "hyperlipidemia" and "menopause" were searched in the databases with varying combinations. CONCLUSION Consumption of flaxseed in different forms has valuable effects and protects against cardiovascular disease, hypertension, diabetes, dyslipidemia, inflammation and some other complications. Flaxseed can serve as a promising candidate for the management of metabolic syndrome to control blood lipid levels, fasting blood sugar, insulin resistance, body weight, waist circumference, body mass and blood pressure.
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Dietary Fibre May Mitigate Sarcopenia Risk: Findings from the NU-AGE Cohort of Older European Adults.
Montiel-Rojas, D, Nilsson, A, Santoro, A, Franceschi, C, Bazzocchi, A, Battista, G, de Groot, LCPGM, Feskens, EJM, Berendsen, A, Pietruszka, B, et al
Nutrients. 2020;(4)
Abstract
Sarcopenia is characterised by a progressive loss of skeletal muscle mass and physical function as well as related metabolic disturbances. While fibre-rich diets can influence metabolic health outcomes, the impact on skeletal muscle mass and function is yet to be determined, and the moderating effects by physical activity (PA) need to be considered. The aim of the present study was to examine links between fibre intake, skeletal muscle mass and physical function in a cohort of older adults from the NU-AGE study. In 981 older adults (71 ± 4 years, 58% female), physical function was assessed using the short-physical performance battery test and handgrip strength. Skeletal muscle mass index (SMI) was derived using dual-energy X-ray absorptiometry (DXA). Dietary fibre intake (FI) was assessed by 7-day food record and PA was objectively determined by accelerometery. General linear models accounting for covariates including PA level, protein intake and metabolic syndrome (MetS) were used. Women above the median FI had significantly higher SMI compared to those below, which remained in fully adjusted models (24.7 ± 0.2% vs. 24.2 ± 0.1%, p = 0.011, η2p = 0.012). In men, the same association was only evident in those without MetS (above median FI: 32.4 ± 0.3% vs. below median FI: 31.3 ± 0.3%, p = 0.005, η2p = 0.035). There was no significant impact of FI on physical function outcomes. The findings from this study suggest a beneficial impact of FI on skeletal muscle mass in older adults. Importantly, this impact is independent of adherence to guidelines for protein intake and PA, which further strengthens the potential role of dietary fibre in preventing sarcopenia. Further experimental work is warranted in order to elucidate the mechanisms underpinning the action of dietary fibre on the regulation of muscle mass.
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Addition of oat bran reduces HDL-C and does not potentialize effect of a low-calorie diet on remission of metabolic syndrome: A pragmatic, randomized, controlled, open-label nutritional trial.
Leão, LSCS, Aquino, LA, Dias, JF, Koifman, RJ
Nutrition (Burbank, Los Angeles County, Calif.). 2019;:126-130
Abstract
OBJECTIVES It is unclear whether addition of soluble fiber to a low-calorie diet potentializes weight loss and amelioration of metabolic syndrome (MetS). The aim of this study was to analyze the effects of oat bran on prevalence of MetS and associated disorders. METHODS A pragmatic, randomized controlled, 6-wk nutritional trial was carried out with 154 outpatients (mean age 47.6 ± 12.6 y of age). The intervention group (n = 83) received a low-calorie diet plus 40 g/d of oat bran; the control group (n = 71) received a low-calorie diet only. MetS parameters and prevalence were calculated and compared (using two-tailed statistical tests) before and after follow-up. RESULTS After follow-up, a significant but similar reduction was observed in MetS prevalence (40% reduction, 63% and 64.8% prevalence in intervention and control groups, respectively; P = 0.226), body mass index, body weight, waist circumference, systolic and diastolic blood pressures, triacylglycerides, and blood glucose levels in both groups (P < 0.05). Mean high-density lipoprotein cholesterol (HDL-C) was reduced in the intervention group (43.6 ± 9.6 to 41.2 ± 9.5 mg/dL; P = 0.025), but not in the control group (44.6 ± 10.5 to 44.5 ± 12.1 mg/dL; P = 0.890). There was no significant difference in any of the variables between the groups, although the P-value for HDL-C was almost significant (P = 0.078). Calorie and dietetic fiber intake during the 6-wk period were similar in both groups. CONCLUSIONS Daily consumption of oat bran did not potentialize the beneficial effects of a traditional low-calorie diet on the prevalence of MetS and associated disorders. Additionally, it reduced HDL-C.
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Effects of Whole Grain Wheat Bread on Visceral Fat Obesity in Japanese Subjects: A Randomized Double-Blind Study.
Kikuchi, Y, Nozaki, S, Makita, M, Yokozuka, S, Fukudome, SI, Yanagisawa, T, Aoe, S
Plant foods for human nutrition (Dordrecht, Netherlands). 2018;(3):161-165
Abstract
Metabolic syndrome is a risk factor for cardiovascular diseases and has become increasingly common in Japan. Epidemiological studies show inverse associations between intake of whole wheat grains and metabolic syndrome, but few dietary intervention trials have investigated the effect of whole wheat grain consumption. It was investigated whether a diet in which refined wheat bread (RW diet) was substituted by whole grain wheat bread (WW diet) would reduce visceral fat obesity in Japanese subjects. A randomized double-blind placebo-controlled intervention study was conducted in 50 Japanese subjects with body mass index (BMI) ≥ 23 kg/m2. Subjects were randomly assigned WW (WW group) or RW diets (RW group) for 12 weeks. Blood samples and computed tomography scans were obtained every 6th week. The WW group showed decrease (-4 cm2) in visceral fat area (VFA) (p < 0.05), whereas the RW group showed no significant changes. These time-dependent changes were significantly different between the groups. WW diet led to significant and safe reductions in VFA in subjects with BMI ≥ 23 kg/m2. WW diet may contribute to preventing visceral fat obesity.
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Dietary fiber intake and risk of metabolic syndrome: A meta-analysis of observational studies.
Wei, B, Liu, Y, Lin, X, Fang, Y, Cui, J, Wan, J
Clinical nutrition (Edinburgh, Scotland). 2018;(6 Pt A):1935-1942
Abstract
BACKGROUND & AIMS Epidemiological studies show inconsistent findings on the association of dietary fiber intake with risk of metabolic syndrome (MetS). Herein, we aim to conduct a meta-analysis of published studies to determine the role of dietary fiber in prevention of MetS. METHODS A systematical search in PubMed and Embase databases through December 2016, together with reference scrutiny of relevant literature, was performed to identify studies for inclusion. We aggregated the odds ratios (ORs) with 95% confidence intervals (CIs) of MetS using a random effect model. Dose-response relationship between fiber intake and MetS was also evaluated. RESULTS This meta-analysis included 8 cross-sectional and 3 cohort studies, totaling 28,241 participants and 9140 MetS cases. The highest versus lowest fiber intake was associated with a reduced risk of MetS (OR: 0.85, 95% CI: 0.79-0.92; P = 0.005), with moderate heterogeneity (I2 = 64%, P = 0.001) across studies. The benefit of fiber intake was significant among cross-sectional studies (OR: 0.85, 95% CI: 0.78-0.92; P < 0.001) but not among cohort studies (OR: 0.86, 95% CI: 0.70-1.06; P = 0.16). In dose-response analysis, we found a curvilinear relationship between fiber consumption and prevalence of MetS. Compared with non-fiber intake, the ORs (95% CIs) of MetS across fiber intake levels were 0.85 (0.79-0.91), 0.76 (0.67-0.85), 0.73 (0.65-0.83), and 0.73 (0.65-0.82) for 10, 20, 30, and 40 g/d, respectively. CONCLUSIONS Dietary fiber intake is associated with less likelihood of having MetS. Additional large, prospective studies are warranted to enhance our findings.
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The Consumption of Beef Burgers Prepared with Wine Grape Pomace Flour Improves Fasting Glucose, Plasma Antioxidant Levels, and Oxidative Damage Markers in Humans: A Controlled Trial.
Urquiaga, I, Troncoso, D, Mackenna, MJ, Urzúa, C, Pérez, D, Dicenta, S, de la Cerda, PM, Amigo, L, Carreño, JC, Echeverría, G, et al
Nutrients. 2018;(10)
Abstract
Wine grape pomace flour (WGPF) is a fruit byproduct that is high in fiber and antioxidants. We tested whether WGPF consumption could affect blood biochemical parameters, including oxidative stress biomarkers. In a three-month intervention study, 27 male volunteers, each with some components of metabolic syndrome, consumed a beef burger supplemented with 7% WGPF containing 3.5% of fiber and 1.2 mg gallic equivalents (GE)/g of polyphenols (WGPF-burger), daily, during the first month. The volunteers consumed no burgers in the second month, and one control-burger daily in the third month. At baseline and after these periods, we evaluated the metabolic syndrome components, plasma antioxidant status (i.e., 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity (DPPH), vitamin E, vitamin C), and oxidative damage markers (i.e., advanced oxidation protein products (AOPPs), oxidized low-density lipoproteins (oxLDLs), malondialdehyde (MDA)). The WGPF-burger intake significantly reduced glycemia and homeostatic model assessment-based measurement of insulin resistance. Vitamin C increased and decreased during the consumption of the WGPF-burger and control-burger, respectively. The WGPF-burger intake significantly decreased AOPP and oxLDL levels. Vitamin E and MDA levels showed no significant changes. In conclusion, the consumption of beef burgers prepared with WGPF improved fasting glucose and insulin resistance, plasma antioxidant levels, and oxidative damage markers. Therefore, this functional ingredient has potential as a dietary supplement to manage chronic disease risk in humans.