Increased Fiber Intake Research Articles

How does the addition of mushrooms and their dietary fibre affect starchy foods

Mushrooms contain multiple bioactive compounds of which dietary fibre is a representative type. Fortification of extracted or naturally derived dietary fibre in staple starchy foods constitutes a strategy to increase fibre intake in terms of cardiovascular disease and other metabolic diseases. Food matrix is viewed as a physical domain containing nutrients in which interactions and behaviours are different from those in isolation or free state. The nutritional effect of mushrooms' addition in the starchy food matrix is reviewed together with the alterations of cooking properties. Prospective studies include nutrients bioaccessibility due to the interfere of dietary fibres in consideration of their types and quality. The future approach to shaping microbial colonisation in the digestive tract through metabolites such as short-chain fatty acids from dietary fibres is required to sustain host physiology and health.

Offering Fiber-Enriched Foods Increases Fiber Intake in Adults With or Without Cardiometabolic Risk: A Randomized Controlled Trial.

IntroductionPrevious efforts to increase fiber intake in the general population were disappointing despite growing awareness of the multiple benefits of a high fiber intake. Aim of the study was to investigate the acceptance and consumption of fiber-enriched foods.MethodsOne hundred and fifteen middle-aged healthy individuals with and without elevated waist circumference (> 102 cm in males and > 88 cm in females) were recruited and randomized to an intervention or an age- and sex-matched control group. Subjects assigned to the intervention group were invited to select fiber-enriched foods from a broad portfolio of products to increase fiber intake by 10 g/day. Control subjects could choose items from the same food basket without fiber enrichment. The primary outcome was the increase in dietary fiber intake, and secondary outcomes were changes in cardiometabolic risk factors, microbiota composition, food choices, and consumer acceptance of the fiber-enriched foods.ResultsCompared to baseline, daily fiber intake increased from 22.5 ± 8.0 to 34.0 ± 9.6 g/day after 4 weeks (p < 0.001) and to 36.0 ± 8.9 g/day after 12 weeks (p < 0.001) in the intervention group, whereas fiber intake remained unchanged in the control group. Participants rated the taste of the food products as pleasant without group differences. In both groups, the most liked foods included popular convenience foods such as pretzel breadstick, pizza salami, and pizza vegetarian. After 12 weeks of intervention, there were minor improvements in plasma lipids and parameters of glucose metabolism in both the intervention and control group compared to baseline, but no differences between the two groups. Increased fiber consumption resulted in an increased (p < 0.001) relative abundance of Tannerellaceae.ConclusionsFiber-enrichment of popular foods increases fiber intake in a middle-aged population with and without cardiometabolic risk and may provide a simple, novel strategy to increase fiber intake in the population.

Substitution of local Indonesian varieties of brown rice on anthropometry and blood glucose level improvement in type 2 DM patients: a pilot project.

Background: Diabetes mellitus (DM) is a metabolic disorder whose prevalence increases globally. Medical nutrition therapy (MNT) is one of the DM management pillars to control blood glucose. Local Indonesian brown rice is proven to contain high fiber and magnesium levels thus could improve obesity, fasting blood glucose, and HbA1c. This study aims to prove the benefits of brown rice on anthropometric parameters and blood glucose control.Design and methods: Respondents were overweight women older than 40 years with type 2 diabetes who were given three main meals and three snacks six days a week for 12 weeks. Anthropometric and blood glucose control data were collected before and after the intervention. Diet and intake data before the intervention were obtained through a semi quantitate food frequency questionnaire. Intake data during the intervention were recorded using the 24-hour food record and analyzed using modified NutriSurvey 2007 software.Results: Brown rice intervention significantly reduced body weight, BMI, body fat percentage, and abdominal circumference (p<0.05), also in fasting blood glucose (FBG), 2-h postprandial blood glucose (PBG), and HbA1c (p<0.05). From the Pearson’s test results, an increase in fiber intake correlated with a decrease in BMI and abdominal circumference (p=0.03; r = -0.511 and p=0.006; r = -0.619, respectively). Meanwhile, magnesium intake and changes in BMI showed a negative correlation.Conclusions: The substitution of brown rice as a staple food for 12 weeks improves anthropometric parameters and blood glucose control in respondents with type 2 diabetes. Significance for public health Diet management is one important point in blood glucose control in diabetes mellitus patients. Ignoring the eating habits of patients given interventions makes diet difficult to be implemented. The tradition of consuming rice as a staple food is a dietary pattern for Indonesians. Selecting brown rice as a staple food in patients with diabetes mellitus has been proven to improve blood glucose control. Clinical trials in this study can be used as a reference for public education regarding the recommended servings of brown rice in daily servings as blood glucose control.

Can implementation intentions increase fibre intake? An examination of the effect of planning and educational information

Can implementation intentions increase fibre intake? An examination of the effect of planning and educational information

A high-fibre personalised dietary advice given via a web tool reduces constipation complaints in adults.

Constipation can greatly impact the quality of life (QoL), which can be relieved by dietary fibres; however, preserving a higher fibre intake remains a challenge. We investigated the effects of a personalised dietary advice (PDA) on fibre intake and mild constipation complaints. A total number of twenty-five adults with mild constipation complaints were included in a 4-week observation period followed by a 4-week personalised intervention. The PDA provided high-fibre alternatives via a web tool. In weeks 1, 4 and 8, dietary intake, constipation complaints and QoL were assessed. Furthermore, participants collected a faecal sample at weeks 1, 4 and 8 to determine microbiota diversity and composition, and short-chain fatty acids (SCFA). Participants completed questions daily for 8 weeks regarding abdominal complaints, stool frequency and stool consistency. Fibre intake in week 8 was significantly higher compared to week 1 (Δ = 5·7 ± 6·7 g, P < 0·001) and week 4 (Δ = 5·2 ± 6·4 g, P < 0·001). Constipation severity and QoL significantly improved at week 8 compared to the observation period (P < 0·001). A higher fibre intake significantly reduced constipation severity (β = -0·031 (-0·05; -0·01), P = 0·001) and the QoL (β = -0·022 (-0·04; -0·01), P = 0·009). Stool consistency (P = 0·040) and abdominal pain (P = 0·030) improved significantly during the intervention period (P = 0·040), but stool frequency did not. Average microbial alpha diversity and composition and SCFA concentrations did not change over time, but indicated individual-specific dynamics. Several SCFAs were associated with constipation complaints. To conclude, a PDA effectively increased fibre intake and subsequently reduced constipation complaints, indicating that guided dietary adjustments are important and feasible in the treatment of mild constipation complaints.

High-fiber personalized dietary advice reduces constipation complaints

Rationale: Constipation is characterized by hard stools and infrequent bowel movements, and greatly impacts quality of life (QoL). A high fiber intake can help relieve constipation, however sustainably increasing fiber intake remains a challenge. Therefore, we investigated the effects of a personalized dietary advice (PDA) on constipation complaints and fiber intake in adults with constipation.

A fiber-deprived diet causes cognitive impairment and hippocampal microglia-mediated synaptic loss through the gut microbiota and metabolites

BackgroundCognitive impairment, an increasing mental health issue, is a core feature of the aging brain and neurodegenerative diseases. Industrialized nations especially, have experienced a marked decrease in dietary fiber intake, but the potential mechanism linking low fiber intake and cognitive impairment is poorly understood. Emerging research reported that the diversity of gut microbiota in Western populations is significantly reduced. However, it is unknown whether a fiber-deficient diet (which alters gut microbiota) could impair cognition and brain functional elements through the gut-brain axis.ResultsIn this study, a mouse model of long-term (15 weeks) dietary fiber deficiency (FD) was used to mimic a sustained low fiber intake in humans. We found that FD mice showed impaired cognition, including deficits in object location memory, temporal order memory, and the ability to perform daily living activities. The hippocampal synaptic ultrastructure was damaged in FD mice, characterized by widened synaptic clefts and thinned postsynaptic densities. A hippocampal proteomic analysis further identified a deficit of CaMKIId and its associated synaptic proteins (including GAP43 and SV2C) in the FD mice, along with neuroinflammation and microglial engulfment of synapses. The FD mice also exhibited gut microbiota dysbiosis (decreased Bacteroidetes and increased Proteobacteria), which was significantly associated with the cognitive deficits. Of note, a rapid differentiating microbiota change was observed in the mice with a short-term FD diet (7 days) before cognitive impairment, highlighting a possible causal impact of the gut microbiota profile on cognitive outcomes. Moreover, the FD diet compromised the intestinal barrier and reduced short-chain fatty acid (SCFA) production. We exploit these findings for SCFA receptor knockout mice and oral SCFA supplementation that verified SCFA playing a critical role linking the altered gut microbiota and cognitive impairment.ConclusionsThis study, for the first time, reports that a fiber-deprived diet leads to cognitive impairment through altering the gut microbiota-hippocampal axis, which is pathologically distinct from normal brain aging. These findings alert the adverse impact of dietary fiber deficiency on brain function, and highlight an increase in fiber intake as a nutritional strategy to reduce the risk of developing diet-associated cognitive decline and neurodegenerative diseases.2_wgC4CVAKtYwCNZbg5Y4xVideo

Changes in Plasma Choline and the Betaine-to-Choline Ratio in Response to 6-Month Lifestyle Intervention Are Associated with the Changes of Lipid Profiles and Intestinal Microbiota: The ICAAN Study.

Trimethylamine N-oxide (TMAO) and its precursors, including choline, betaine, and L-carnitine, are gut microbiota-related metabolites associated with the risk of obesity. We aimed (1) to comprehensively examine whether the changes in plasma TMAO and its precursors induced by lifestyle intervention are associated with the improvements in plasma metabolic parameters; and (2) to identify the fecal microbiome profiles and nutrient intakes associated with these metabolites and metabolic index. Data from 40 participants (obese children and adolescents) having the plasma metabolites data related to the changes in BMI z-scores after 6-month lifestyle intervention were analyzed. In this study, we observed that choline and the betaine-to-choline ratio (B/C) showed different patterns depending on the changes in BMI z-scores by the response to lifestyle intervention. During the 6 months, an increase in choline and a decrease in B/C were observed in non-responders. We also found that changes in choline and B/C were associated with the improvements in plasma lipid levels. Individuals who showed reduced choline or increased B/C from the baseline to 6 months had a significant decrease in LDL-cholesterol over 6 months compared to those with increased choline or decreased B/C, respectively. In addition, the increase in choline or decrease in B/C was associated with the increase in plasma triglycerides. The distribution of gut microbiota belonging to the Firmicutes, such as Clostridia, Clostridiales, Peptostreptococcaceae, Romboutsia, and Romboutsia timonensis was altered to be lower during the 6 months both as choline decreased and B/C increased. Moreover, the decrease in choline and the increase in B/C were associated with reduced fat intake and increased fiber intake after the 6-month intervention. Finally, lower abundance of Romboutsia showed the association with lower LDL-cholesterol and higher intake of fiber. In summary, we demonstrated that reduced choline and increased B/C by lifestyle intervention were associated with the improvements of LDL-cholesterol and triglycerides, low-fat and high-fiber intakes, and low abundance of Firmicutes. These indicate that changes to circulating choline and B/C could predict individuals’ changes in metabolic compositions in response to the lifestyle intervention.

World Gastroenterology Organisation Global Guidelines: Diet and the Gut.

World Gastroenterology Organisation Global Guidelines: Diet and the Gut.

Estimating the health impact of individual's dietary change across multiple physiological outcomes: a conceptual and simulation model

BackgroundInterventions to improve the food environment are often implemented at the population level. The health effects of these interventions can be difficult to observe but can be predicted by models. Prediction models require evidence from multiple sources if changes to diet affect sodium, fat, and carbohydrate consumption. We aimed to develop a model to estimate how multidimensional changes in individuals' diets affect metabolic risk factors. MethodsWe developed an evidence review to identify mathematical models describing relationships between calories and weight in adults, and systematic reviews estimating relationships between fats, carbohydrates, and sodium on systolic blood pressure (SBP), cholesterol, and HbA1c from randomised controlled trials. We searched the MEDLINE, Embase, Cochrane Library, and Science Citation Index databases for peer-reviewed systematic reviews published in English between 1946 and May 26, 2020 using keywords for metabolic risks and nutrients . A systems map combining the School for Public Health Research (SPHR) Diabetes Prevention model, background literature, and dietary public health policies was used to develop the review protocol. Data extracted from the review were used to develop a conceptual map to illustrate the causal relationships between dietary measures and metabolic risk factors, including the effects of food substitutions (carbohydrates vs fats). The map was discussed with two senior lecturers in nutrition to identify evidence gaps and additional evidence. The map was programmed into a deterministic simulation in R to estimate how changes in diet affect metabolic risk factors. FindingsWe estimated that reducing calorie intake by 50 kcal per day would reduce population mean weight by 1·3 kg over 12 months. Reducing sodium intake by 1 g per day would decrease population mean SBP by 0·212 mm Hg. Increasing fibre intake by 1 g per day would decrease SBP by 0·200 mm Hg over 12 months, with marginal decreases in weight, HbA1c, and LDL cholesterol. Substituting carbohydrates for polyunsaturated fat (2·5% of energy) would decrease population mean total cholesterol by 0·12 mmol/L over 12 months, with marginal reductions in SBP and weight. InterpretationThis study provides a tool to estimate effects of dietary changes on individual physiological indicators of health. The research will be most beneficial to extrapolate health effects of population-level food interventions, including those leading to multiple, and possibly, competing nutritional effects. FundingNational Institute for Health Research School for Public Health Research (grant reference number PD-SPH-2015).

Modeling the Effect of Environmentally Sustainable Food Swaps on Nutrient Intake in Pregnant Women.

Food production greatly contributes to greenhouse gas emissions (GHG), but there remain concerns that consuming environmentally sustainable foods can increase the likelihood of nutritional deficiencies during pregnancy. We identified commonly consumed foods of pregnant women and determined the effect of their replacement with environmentally sustainable alternatives on nutrient intake and measures of environmental sustainability. Dietary intake data from 171 pregnant women was assessed and foods that contributed the most to energy and protein intake were identified. Of these, foods producing the highest GHG emissions were matched with proposed environmentally sustainable alternatives, and their impact on nutrient provision determined. Meats, grains, and dairy products were identified as important sources of energy and protein. With the highest GHG emissions, beef was selected as the reference food. Proposed alternatives included chicken, eggs, fish, tofu, legumes, and nuts. The most pronounced reductions in CO2 emissions were from replacing beef with tofu, legumes, and nuts. Replacing one serve per week of beef with an isocaloric serve of firm tofu during pregnancy could reduce GHG emissions by 372 kg CO2 eq and increase folate (+28.1 µg/serve) and fiber (+3.3 g/serve) intake without compromising iron (+1.1 mg/serve) intake. Small dietary substitutions with environmentally sustainable alternatives can substantially reduce environmental impact without compromising nutrient adequacy.

Fiber intake and health in people with chronic kidney disease.

Emerging evidence suggests that diet, particularly one that is rich in dietary fiber, may prevent the progression of chronic kidney disease (CKD) and its associated complications in people with established CKD. This narrative review summarizes the current evidence and discusses the opportunities for increasing fiber intake in people with CKD to improve health and reduce disease complications. A higher consumption of fiber exerts multiple health benefits, such as increasing stool output, promoting the growth of beneficial microbiota, improving the gut barrier and decreasing inflammation, as well decreasing uremic toxin production. Despite this, the majority of people with CKD consume less than the recommended dietary fiber intake, which may be due in part to the competing dietary potassium concern. Based on existing evidence, we see benefits from adopting a higher intake of fiber-rich food, and recommend cooperation with the dietitian to ensure an adequate diet plan. We also identify knowledge gaps for future research and suggest means to improve patient adherence to a high-fiber diet.

Future of food: Innovating towards sustainable healthy diets

Future of food: Innovating towards sustainable healthy diets

Association Between Microbe Accessible Carbohydrates (MACs) Intake and Healthy Eating Index (HEI-2015) in the College Students

ObjectivesYoung adults tend to consume western diets with low microbe-accessible carbohydrates (MACs), which are fermentable carbohydrates that may reduce the risk of developing non-communicable diseases. The importance of dietary fiber (only one type of MAC) in the prevention of chronic diseases led to recommendations for increasing fiber intake. However, a reference to other MACs such as resistant starches, non-starch polysaccharides, polyols (lactitol, sorbitol, etc.), and oligosaccharides (fructo-oligosaccharides, etc.) is still lacking and their relationship with diet quality is far less understood. The healthy eating index (HEI) score is a measure of diet quality, independent of quantity, and is useful to assess compliance with U.S. Dietary Guidelines for Americans. The primary aim of this study was to determine the MACs consumption in healthy US college students and their association with dietary quality as indicated by the HEI-2015. MethodsFor this cross-sectional study, data were collected from consenting students (≥ 18years old) in an introductory nutrition course (n = 592, age (mean ± standard deviation) 19.5 ± 3.5; 83.7% white; 78.4% female). Dietary intake was measured via a web-based dietary history questionnaire (DHQ-II), which is able to quantify the consumption of MAC’s and subclasses such as polyols and soluble dietary fibers. DHQ website provided step by step instructions to calculate HEI in SAS (SAS enterprise guide 7.4). Linear regression was run to determine the association between the average daily intake of MACs and the HEI-2015 score. ResultsAverage MAC intake was 7.7 ± 4.4 grams with most of the amounts coming from soluble dietary fibers (6.6 ± 3.8). The mean HEI-score of this population was 64.9 ± 10.8. Average daily consumption of MAC was significantly associated with HEI score, F(1,590) = 65.22, P = 0.000, accounting for 10% of the variation in HEI-score with adjusted R2 = 9.8%, a medium-size effect according to Cohen (1988). An extra gram of daily average intake of MAC led to a 0.78 (95% CI, 0.59 to 0.97) increase in HEI-score. ConclusionsMAC intake was associated with an increase in HEI-2015 score; however, the total MAC intake was low in this population of college students. Therefore, more efforts are needed to increase the consumption of MACs not just dietary fibers in college students. Funding SourcesNone.

Dietary Carbohydrate Intake Glycemic Index and Glycemic Load and the Risk of Prostate Cancer among Iranian Men: A Case-Control Study

Previous studies have presented a few evidences on the relationship between dietary carbohydrate intake, glycemic index (GI), glycemic load (GL), with the prostate cancer risk. We performed a case-control study to evaluate these associations in 50 men with histologically confirmed prostate cancer and 100 control men. Odds ratios (ORs) and their corresponding 95% confidence intervals (95% CIs) were derived using logistic regression. The fully adjusted ORs for the top vs. the bottom quartile were 15.02 (P trend = 0.004), 1.04 (P trend = 0.003), and 10.35 (P trend = 0.002) for carbohydrate intake, GI and GL, respectively. Significant associations with prostate cancer remained only among men with reduced fiber intake for carbohydrate intake, GI and GL and among those had increased fiber intake for GI. These findings support the hypothesis that diet with high carbohydrate, GI and GL enhance risk of prostate cancer.

Malnutrition is Associated with Gut Dysbiosis and Perioperative Infections in LVAD Patients

<h3>Purpose</h3> Malnutrition is common in heart failure (HF) and contributes to poor outcomes. Nutrient metabolism might be influenced by the complex interplay between HF progression, venous congestion, inflammation and gut dysbiosis. We investigated the association between nutritional status and: i) biomarkers of congestion and inflammation; ii) gut microbial diversity; and iii) perioperative infections among HF pts undergoing LVAD. <h3>Methods</h3> From 8/2016 to 8/2018, hospitalized pts with prospectively collected stool and blood samples prior to LVAD and a nutritional assessment were retrospectively reviewed. Nutritional status was assessed according to current guidelines. Pts were divided into 2 groups: no malnutrition vs malnutrition (≥moderate). Calorie and fiber consumption over 7-day period pre-LVAD was averaged. Serum biomarkers of congestion (NT-proBNP) and inflammation (CRP) were measured. Stool samples were analyzed using 16S rRNA sequencing and summarized both at the taxa level, and overall using the Shannon index (a composite metric of gut alpha-diversity). Regression analyses explored differences in Shannon index and individual taxa (via DESeq) by nutritional status. <h3>Results</h3> 37 pts (56 ±12.6 y, 92% M) were included. 10 (27%) had malnutrition. Malnourished pts had significantly lower Shannon Index (Fig 1A). A positive correlation was found between Shannon index and calorie (r =.36, <i>p</i>=.027) and fiber intake (r= .32, <i>p</i>=.05). We observed n=3 taxa, all with anti-inflammatory properties, to be significantly enriched in pts without malnutrition (Fig 1B). Pre-LVAD levels of NT-proBNP and CRP were similar between groups. Perioperative infections were more prevalent in pts with malnutrition (Fig 1C); specifically, pre-LVAD 50% vs 18% and post-LVAD infections 60% vs 26%, both <i>p</i>=.05. <h3>Conclusion</h3> Malnutrition is associated with gut dysbiosis and perioperative infections in HF pts undergoing LVAD. Proof of principle trials to increase fiber intake and reduce gut dysbiosis and infection are justified.

Metabolic and satiating effects and consumer acceptance of a fibre-enriched Leberkas meal: a randomized cross-over trial.

The Western diet is poor in dietary fibre and previous efforts to increase fibre intake were not successful. The aim of this study was to develop sensorically appealing, fibre-enriched convenience foods. As a showcase, we prepared a fibre-enriched, fat-reduced Leberkas served in a roll and compared the reformulated product with the standard product. The design was a randomized, single-blinded cross-over study. A Leberkas meal enriched with 19.2g of wheat fibre and resistant dextrin as well as fat- and energy-reduced (30% less calories) was served to 20 middle-aged healthy volunteers (10 male, 10 female) and compared to the standard product in a random order. Blood was repeatedly taken over a 4h period to measure metabolic parameters as well as satiety hormones, such as glucagon-like-peptide 1, cholecystokinin, peptide YY. Satiety and consumer acceptance of the fibre-enriched meal were assessed by visual analogue scales and a questionnaire. The fibre-enriched meal showed very small significant effects at only single time points in postprandial blood glucose (at 120min, p = 0.050) and glucoseAUC fibre 22,079 ± 2819, standard 22,912 ± 3583 (p = 0.030). The profiles of satiety hormones were comparable between both meals. No differences in subjective satiation, taste and consumer acceptance were observed between the two products, despite a marked reduction in fat and energy content of the reformulated product. It is possible to enrich a popular convenience product with dietary fibre and to markedly reduce energy content without loss of sensory qualities or satiety suggesting that development and promotion of healthier convenience foods may be a useful strategy to tackle obesity and other diet-related diseases.

Differential response to a 6-month energy-restricted treatment depending on SH2B1 rs7359397 variant in NAFLD subjects: Fatty Liver in Obesity (FLiO) Study.

Non-alcoholic fatty liver disease (NAFLD) is worldwide recognized as the most common cause of chronic liver disease. Current NAFLD clinical management relies on lifestyle change, nevertheless, the importance of the genetic make-up on liver damage and the possible interactions with diet are still poorly understood. The aim of the study was to evaluate the influence of the SH2B1 rs7359397 genetic variant on changes in body composition, metabolic status and liver health after 6-month energy-restricted treatment in overweight/obese subjects with NAFLD. In addition, gene-treatment interactions over the course of the intervention were examined. The SH2B1 genetic variant was genotyped in 86 overweight/obese subjects with NAFLD from the FLiO study (Fatty Liver in Obesity study). Subjects were metabolically evaluated at baseline and at 6-months. Liver assessment included ultrasonography, Magnetic Resonance Imaging, elastography, a lipidomic test (OWL®-test) and specific blood liver biomarkers. Additionally, body composition, general biochemical markers and dietary intake were determined. Both genotypes significantly improved their body composition, general metabolic status and liver health after following an energy-restricted strategy. Liver imaging techniques showed a greater decrease in liver fat content (- 44.3%, p < 0.001) and in serum ferritin levels (p < 0.001) in the carriers of the T allele after the intervention. Moreover, lipidomic analysis, revealed a higher improvement in liver status when comparing risk vs. no-risk genotype (p = 0.006 vs. p = 0.926, respectively). Gene-treatment interactions showed an increase in fiber intake and omega-3 fatty acid in risk genotype (p interaction = 0.056 and p interaction = 0.053, respectively), while a significant increase in MedDiet score was observed in both genotype groups (p = 0.020). Moreover, no-risk genotype presented a relevant decrease in hepatic iron as well as in MUFA intake (p = 0.047 and p = 0.034, respectively). Subjects carrying the T allele of the rs7359397 polymorphism may benefit more in terms of hepatic health and liver status when prescribed an energy-restricted treatment, where a Mediterranean dietary pattern rich in fiber and other components such as omega-3 fatty acids might boost the benefits. The Fatty Liver in Obesity was approved by the Research Ethics Committee of the University of Navarra and retrospectively registered (NCT03183193; www.clinicaltrials.gov ); June 2017.

The Adequacy of Habitual Dietary Fiber Intake in Individuals With Inflammatory Bowel Disease: A Systematic Review

BackgroundDietary fiber may influence disease course in individuals with inflammatory bowel disease (IBD), yet there is a paucity of understanding of habitual fiber intakes. ObjectivesTo identify studies measuring fiber intakes of individuals with IBD, compare the adequacy of fiber intakes with that of control groups or respective national dietary guidelines, and examine factors associated with fiber consumption. MethodsFive electronic databases—MEDLINE, CINAHL, SCOPUS, PROQUEST, and COCHRANE LIBRARY—were systematically searched, using search terms inflammatory bowel disease, Crohn’s disease, ulcerative colitis, dietary intake, and fiber, until December 2019, with hand searching of reference lists. Primary studies were included if fiber intakes were measured in participants 18 years of age or older, with confirmed IBD, with or without comparison to a control. ResultsA total of 2105 publications were identified, and 26 met inclusion criteria. Total fiber intake of 4164 participants with IBD ranged broadly (9.9 ± 7.8 g/day to 21.0 ± 10.5 g/day). Most (18/26) used cross-sectional study design, with a large degree of heterogeneity in tools measuring fiber intake. Sixty-six percent of studies comparing participants with IBD with control groups found that participants with IBD consumed significantly less fiber than control subjects. Four studies reported that less than 10% to 21% of IBD participants met their national fiber recommendations. Data conflicted regarding an association between disease type, disease activity, or rate of relapse and fiber intake. ConclusionsIndividuals with IBD consume less fiber than healthy populations. Fiber intakes are inadequate compared with respective national fiber guidelines. Interpretation of factors associated with fiber intakes were limited by data quality and conflicting results. Future research is required into factors associated with fiber intake and whether increasing fiber intakes can influence disease course and behavior.

Mechanisms of Insulin Resistance at the Crossroad of Obesity with Associated Metabolic Abnormalities and Cognitive Dysfunction.

Obesity mediates most of its direct medical sequelae through the development of insulin resistance (IR). The cellular effects of insulin occur through two main postreceptor pathways that are the phosphatidylinositol 3-kinase (PI3-K) and the mitogen-activated protein kinase (MAP-K) pathways. Obesity-related IR implicates the PI3-K pathway that confers the metabolic effects of insulin. Numerous and complex pathogenic pathways link obesity with the development of IR, including chronic inflammation, mitochondrial dysfunction (with the associated production of reactive oxygen species and endoplasmic reticulum stress), gut microbiota dysbiosis and adipose extracellular matrix remodelling. IR itself plays a key role in the development of metabolic dysfunction, including hypertension, dyslipidaemia and dysglycaemia. Furthermore, IR promotes weight gain related to secondary hyperinsulinaemia, with a resulting vicious cycle of worsening IR and its metabolic sequelae. Ultimately, IR underlies obesity-related conditions such as type 2 diabetes mellitus (T2D) and polycystic ovary syndrome (PCOS). IR also underlies many obesity-related malignancies, through the effects of compensatory hyperinsulinaemia on the relatively intact MAP-K insulin pathway, which controls cellular growth processes and mitoses. Furthermore, the emergent data over recent decades support an important role of obesity- and T2D-related central IR in the development of cognitive dysfunction, including effects on hippocampal synaptic plasticity. Importantly, IR is largely reversible through the optimisation of lifestyle factors that include regular engagement in physical activity with the avoidance of sedentariness, improved diet including increased fibre intake and sleep sufficiency. IR lies at the key crossroad between obesity and both metabolic and cognitive dysfunction. Given the importance of IR in the pathogenesis of many 21st century chronic diseases and its eminent reversibility, it is important that we all embrace and facilitate optimised lifestyles to improve the future health and wellbeing of the populace.