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Emerging science on benefits of whole grain oat and barley and their soluble dietary fibers for heart health, glycemic response, and gut microbiota.
Tosh, SM, Bordenave, N
Nutrition reviews. 2020;(Suppl 1):13-20
Abstract
The aim of this work is to review the major mechanisms by which consumption of whole grain oats and barley, and β-glucans, reduces the risk of coronary heart disease, type 2 diabetes, and other noncommunicable chronic conditions. These effects have been predominantly explained by the role of soluble dietary fibers and smaller bioactive compounds, such as phenolic compounds, in oats and barley. These help to reduce the level of serum low-density lipoprotein cholesterol, decreasing postprandial blood glucose and modulating gut microbiota. In the present review, the role of viscosity development of the intestinal content by β-glucans in these mechanisms is discussed, as well as the impact of processing conditions altering the composition or the physicochemical characteristics of β-glucans.
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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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Importance of the Microbiota Inhibitory Mechanism on the Warburg Effect in Colorectal Cancer Cells.
Eslami, M, Sadrifar, S, Karbalaei, M, Keikha, M, Kobyliak, NM, Yousefi, B
Journal of gastrointestinal cancer. 2020;(3):738-747
Abstract
METHODS AND RESULTS Colorectal cancer (CRC) is the third most common cancer in the world. Genetic backgrounds, lifestyle, and diet play an important role in CRC risk. The human gut microbiota has an influence on many features of human physiology such as metabolism, nutrient absorption, and immune function. Imbalance of the microbiota has been implicated in many disorders including CRC. It seems Warburg effect hypothesis corresponds to the early beginning of carcinogenesis because of eventual failure in the synthesis of a pyruvate dehydrogenase complex in cooperation with a supply of glucose in carbohydrates rich diets. From investigation among previous publications, we attempted to make it clear importance of Warburg effect in tumors; it also discusses the mechanisms of probiotics in inhibiting tumor progression and reverse Warburg effect of probiotics in modulating the microbiota and CRC therapies. These effects were observed in some clinical trials, the application of probiotics as a therapeutic agent against CRC still requirements further investigation. CONCLUSION Fiber is fermented by colonic bacteria into SCFAs such as butyrate/acetate, which may play a vital role in normal homeostasis by promoting turnover of the colonic epithelium. Butyrate enters the nucleus and functions as a histone deacetylase inhibitor (HDACi). Because cancerous colonocytes undertake the Warburg effect pathway, their favored energy source is glucose instead of butyrate. Therefore, accumulation of moderate concentrations of butyrate in cancerous colonocytes and role as HDACi. Probiotics have been shown to play a protective role against cancer development by modulating intestinal microbiota and immune response.
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The Role of Dietary Fibre in Modulating Gut Microbiota Dysbiosis in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis of Randomised Controlled Trials.
Ojo, O, Feng, QQ, Ojo, OO, Wang, XH
Nutrients. 2020;(11)
Abstract
BACKGROUND The prevalence of type 2 diabetes is on the increase worldwide, and it represents about 90% of adults who are diagnosed with diabetes. Overweight and obesity, lifestyle, genetic predisposition and gut microbiota dysbiosis have been implicated as possible risk factors in the development of type 2 diabetes. In particular, low intake of dietary fibre and consumption of foods high in fat and sugar, which are common in western lifestyle, have been reported to contribute to the depletion of specific bacterial taxa. Therefore, it is possible that intake of high dietary fibre may alter the environment in the gut and provide the needed substrate for microbial bloom. AIM: The current review is a systematic review and meta-analysis which evaluated the role of dietary fibre in modulating gut microbiota dysbiosis in patients with type 2 diabetes. METHODS This is a systematic review and meta-analysis of randomised controlled trials which relied on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework. Electronic searches were conducted using EBSCOHost with links to Health Sciences Research Databases, EMBASE and Google Scholar. The reference lists of articles were also searched for relevant studies. Searches were conducted from date of commencement of the database to 5 August 2020. The search strategy was based on the Population, Intervention, Comparator, Outcomes, Studies (PICOS) framework and involved the use of synonyms and medical subject headings (MesH). Search terms were combined with Boolean operators (OR/AND). RESULTS Nine studies which met the inclusion criteria were selected for the systematic review and meta-analysis, and four distinct areas were identified: the effect of dietary fibre on gut microbiota; the role of dietary fibre on short-chain fatty acids (SCFAs); glycaemic control; and adverse events. There was significant difference (p < 0.01) in the relative abundance of Bifidobacterium with a mean difference of 0.72 (95% CI, 0.56, 0.89) between the dietary fibre group compared with placebo. In relation to the meta-analysis for SCFAs, while there was significant difference (p = 0.02) between the dietary fibre group and placebo with a standardised mean difference of 0.5 (95% CI, 0.08, 0.91) regarding total SCFAs, the differences were not significant (p > 0.05) in relation to acetic acid, propionic acid and butyric acid. There was only significant improvement (p = 0.002) with respect to glycated haemoglobin with a mean difference of -0.18 (95% CI, -0.29, -0.06) between the dietary fibre group and placebo group. Differences between the two groups were not significant (p > 0.05) in relation to fasting blood glucose and homeostatic model assessment of insulin resistance (HOMA-IR). Furthermore, there were no significant differences between the two groups in subjects who reported adverse events. It is possible that the promotion of SCFA producers in greater diversity and abundance by dietary fibre in this review led to improvement in glycated haemoglobin, partly due to increased glucagon-like peptide-1 (GLP-1) production. In addition, Bifidobacterium lactis has been reported to increase glycogen synthesis, decrease expression of hepatic gluconeogenesis genes, improve translocation of glucose transport-4 and promote glucose uptake. It is also possible that the reduction in body weight of participants in the intervention group compared with control may have contributed to the observed improvement in glycated haemoglobin. CONCLUSION This systematic review and meta-analysis have demonstrated that dietary fibre can significantly improve (p < 0.05) the relative abundance of Bifidobacterium, total SCFAs and glycated haemoglobin. However, dietary fibre did not appear to have significant effect (p > 0.05) on fasting blood glucose, HOMA-IR, acetic acid, propionic acid, butyric acid and adverse events.
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Impact of a low-carbohydrate and high-fiber diet on nonalcoholic fatty liver disease.
Chen, J, Huang, Y, Xie, H, Bai, H, Lin, G, Dong, Y, Shi, D, Wang, J, Zhang, Q, Zhang, Y, et al
Asia Pacific journal of clinical nutrition. 2020;(3):483-490
Abstract
BACKGROUND AND OBJECTIVES To study the effects of a low-carbohydrate and high-fiber diet and education on patients with nonalcoholic fatty liver disease. METHODS AND STUDY DESIGN We randomly divided 44 patients with nonalcoholic fatty liver disease into two groups: low-carbohydrate and high-fiber diet and education (intervention group), and education alone (control group). Liver and kidney function, fasting plasma glucose, insulin resistance index, body composition, and controlled attenuation parameter were detected before and after the intervention. RESULTS After 2 months, the body fat, body weight, abdominal circumference, and visceral fat area, fasting plasma glucose, insulin resistance index, and levels of serum alanine aminotransferase, aspartate transaminase, uric acid, and insulin of the intervention group were significantly lower than before (p<0.05). In the female intervention group, the insulin resistance index and levels of serum alanine aminotransferase, uric acid, triglyceride, fasting plasma glucose, and C-peptide were lower and the level of serum high-density lipoprotein cholesterol was higher than in the female control group (p<0.05). In the male intervention group, the levels of serum alanine aminotransferase, triglyceride, and fasting plasma glucose were lower and the level of serum high-density lipoprotein cholesterol was higher compared with the male control group (p<0.05). CONCLUSIONS A low-carbohydrate and high-fiber diet and education can effectively reduce the body weight and body fat of patients with nonalcoholic fatty liver disease and improve metabolic indicators such as liver enzymes, blood glucose, blood lipid, and uric acid. Our female patients showed significantly better improvement in the indicators than our male patients.
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Diet and the Human Gut Microbiome: An International Review.
Wilson, AS, Koller, KR, Ramaboli, MC, Nesengani, LT, Ocvirk, S, Chen, C, Flanagan, CA, Sapp, FR, Merritt, ZT, Bhatti, F, et al
Digestive diseases and sciences. 2020;(3):723-740
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Abstract
This review summarizes the key results of recently published studies on the effects of dietary change and nutritional intervention on the human microbiome from around the world, focusing on the USA, Canada, Europe, Asia, and Africa. It first explores mechanisms that might explain the ability of fiber-rich foods to suppress the incidence and mortality from westernized diseases, notably cancers of the colon, breast, liver, cardiovascular, infectious, and respiratory diseases, diabetes, and obesity (O'Keefe in Lancet Gastroenterol Hepatol 4(12):984-996, 2019; Am J Clin Nutr 110:265-266, 2019). It summarizes studies from Africa which suggest that disturbance of the colonic microbiome may exacerbate chronic malnutrition and growth failure in impoverished communities and highlights the importance of breast feeding. The American section discusses the role of the microbiome in the swelling population of patients with obesity and type 2 diabetes and examines the effects of race, ethnicity, geography, and climate on microbial diversity and metabolism. The studies from Europe and Asia extoll the benefits of whole foods and plant-based diets. The Asian studies examine the worrying changes from low-fat, high-carbohydrate diets to high-fat, low-carbohydrate ones and the increasing appearance of westernized diseases as in Africa and documents the ability of high-fiber traditional Chinese diets to reverse type 2 diabetes and control weight loss. In conclusion, most of the studies reviewed demonstrate clear changes in microbe abundances and in the production of fermentation products, such as short-chain fatty acids and phytochemicals following dietary change, but the significance of the microbiota changes to human health, with the possible exception of the stimulation of butyrogenic taxa by fiber-rich foods, is generally implied and not measured. Further studies are needed to determine how these changes in microbiota composition and metabolism can improve our health and be used to prevent and treat disease.
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Fibre Intake Is Associated with Cardiovascular Health in European Children.
Larrosa, S, Luque, V, Grote, V, Closa-Monasterolo, R, Ferré, N, Koletzko, B, Verduci, E, Gruszfeld, D, Xhonneux, A, Escribano, J
Nutrients. 2020;(1)
Abstract
BACKGROUND We aimed at analysing the association between dietary fibre intake during childhood and cardiovascular health markers. METHODS We used observational longitudinal analysis and recorded diet using 3-day diaries at the ages of 3, 4, 5, 6, and 8 years in children from the EU Childhood Obesity Project Trial. At the age of 8, waist circumference, systolic and diastolic blood pressure (SBP and DBP) and biochemical analyses (lipoproteins, triglycerides and homeostasis model for insulin resistance (HOMA-IR)) were evaluated. Those parameters were combined into a cardiometabolic risk score through the sum of their internal z-scores. RESULTS Four-hundred children (51.8% girls) attended to the 8-year visit with a 3-day diary. Adjusted linear regression models showed that children who repeatedly stayed in the lowest tertile of fibre intake during childhood had higher HOMA-IR (p = 0.004), higher cardiometabolic risk score (p = 0.02) and a nonsignificant trend toward a higher SBP at 8 years. The higher the dietary intake of soluble fibre (from fruits and vegetables) at 8 years, the lower the HOMA-IR and the cardiometabolic risk score (p = 0.002; p = 0.004). SBP was directly associated with fibre from potatoes and inversely with fibre from nuts and pulses. CONCLUSION A diet rich in dietary fibre from fruits, vegetables, pulses and nuts from early childhood was associated to a healthier cardiovascular profile, regardless of children's weight.
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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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An Assessment of the Glyconutrient Ambrotose™ on Immunity, Gut Health, and Safety in Men and Women: A Placebo-Controlled, Double-Blind, Randomized Clinical Trial.
Bloomer, RJ, Butawan, M, van der Merwe, M, Keating, FH
Nutrients. 2020;(6)
Abstract
BACKGROUND Certain dietary fibers have been reported to improve gut health and cellular immunity. Ambrotose is a glyconutrient supplement that contains mannose-rich polysaccharides (acemannan), reported to improve immune function. A more nutrient-dense version of this dietary supplement has been developed recently, with added aloe leaf gel powder (acemannan). The purpose of this study was to evaluate the impact of the traditional and newly developed Ambrotose products on immunity, gut health, and psychological well-being in healthy men and women. METHODS Seventy-five men and women were randomly assigned in double-blind manner to one of five treatments, as follows: Ambrotose Advanced (AA) at 2 or 4 g daily, Ambrotose LIFE (AL) at 2 or 4 g daily, or placebo. Subjects ingested their assigned treatment daily for eight weeks. Resting heart rate, blood pressure, and measures of psychological well-being were analyzed before and after four and eight weeks of supplementation. Blood samples were collected at the same times and analyzed for zonulin, hematology measures, and cytokines-IL-6, IL-10, IL-1β, and TNF-α (analyzed both with and without stimulation via lipopolysaccharide [LPS]). RESULTS All Ambrotose treatments were well-tolerated. There were no differences among treatments in heart rate or blood pressure across time. Self-reported well-being scores were generally higher for the Ambrotose treatments but there were no changes of statistical significance across time (p > 0.05). Differences of statistical significance were noted for select biochemical variables, the most notable being a dramatic decrease in monocytes in the Ambrotose groups. No change was noted in the cytokine response to LPS stimulation in all groups, indicating a maintenance of a healthy immune response. Conclusion: Regular supplementation with Ambrotose is safe and can improve subclinical cellular adversity (as evidenced by a decrease in monocytes), without unnecessary activation of an immune response.
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High-Fiber Diet during Pregnancy Characterized by More Fruit and Vegetable Consumption.
Pretorius, RA, Palmer, DJ
Nutrients. 2020;(1)
Abstract
Higher dietary fiber intakes during pregnancy may have the potential health benefits of increasing gut microbiome diversity, lowering the risk of glucose intolerance and pre-eclampsia, achieving appropriate gestational weight gain, and preventing constipation. In this observational cohort study, we have assessed the dietary fiber intakes of 804 women in late pregnancy, using a semi-quantitative food frequency questionnaire (SQ-FFQ). Overall, the median (interquartile range) dietary fiber intake was 24.1 (19.0-29.7) grams per day (g/day). Only 237/804 (29.5%) women met the recommended Adequate Intake (AI) of dietary fiber during pregnancy of 28 g/day. Women consuming the highest quartile of fiber intakes (34.8 (IQR 32.1-39.5) g/day) consumed more fruit, especially apples and bananas, than women consuming the lowest quartile of fiber intakes (15.9 (IQR 14.4-17.5) g/day). These women in the highest fiber-intake quartile were older (p < 0.01), more had completed further education after secondary school (p = 0.04), and they also consumed more vegetables (67 g/day) compared to the women in the lowest fiber consumption quartile (17 g vegetables/day). Bread intakes of 39-42 g/day were consistent in quantities consumed across all four fiber-intake quartiles. Our findings suggest that antenatal education advice targeting increased fruit and vegetable consumption before and during pregnancy may be a simple strategy to achieve increased total dietary fiber intakes to reach recommended quantities.