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Experimental and Clinical Endocrinology... Mar 2021Dietary fibers may induce satiety through affecting gastro-intestinal and peripheral appetite regulating hormones. Thus, we aimed to investigate the effect of dietary... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Dietary fibers may induce satiety through affecting gastro-intestinal and peripheral appetite regulating hormones. Thus, we aimed to investigate the effect of dietary fiber consumption on serum leptin level compared to control diet, in short- and long- term trials, through a systematic review and meta-analysis.
METHODS
We searched PubMed, web of science, Scopus, ProQuest, EMBASE, and Cochrane Library to find randomized controlled clinical trials that evaluated effect of any type of dietary fiber on serum leptin level compared to control diet, until April 2019. Both short-term (1-4 days) and long-term (longer than 2 weeks) studies were selected. Mean differences (MD) of changes in serum leptin level and 95% confidence intervals were extracted from eligible studies, and random effects model was used to analyze data.
RESULTS
Thirteen studies included the systematic review and 11 entered in the meta-analysis. No significant change was seen in serum leptin level in short-term (MD=0.02, 95% CI; -0.15, 0.20, Tau=0.0) and long-term studies (MD=-0.10, 95% CI; -0.28, 0.08, Tau=0.0), followed by fiber consumption. However, this effect was statistically significant in obese participants (MD=-0.36, 95% CI; -0.71, -0.02, Tau=0.0) in long-term studies. Moreover, we found no significant results in subgroups of baseline serum leptin level, intervention duration, fiber dose, and fiber type.
CONCLUSIONS
This meta-analysis found that taking dietary fiber for long term could lower serum leptin level, just in obese persons. However, further clinical trials are needed in this field to clarify this issue.
Topics: Dietary Fiber; Humans; Leptin; Obesity; Randomized Controlled Trials as Topic
PubMed: 31860117
DOI: 10.1055/a-0998-3883 -
Frontiers in Nutrition 2023Dietary factors may affect the incidence of colorectal serrated polyps (SP). However, its effects on SP are unclear as epidemiological studies on this topic have showed...
BACKGROUND
Dietary factors may affect the incidence of colorectal serrated polyps (SP). However, its effects on SP are unclear as epidemiological studies on this topic have showed inconsistent results. The present systematic review and meta-analysis sought to evaluate the effects of dietary factors on SPs.
METHODS
Studies regarding the association between dietary factors and SPs were identified by searching PubMed, Cochrane library, Embase and Chinese Biomedical Literature database from inception until 27 February 2023. Search terms include serrated, hyperplastic, adenoma, polyps, colorectal, rectal, rectum and risk. Heterogeneity was assessed using statistics. The meta-analysis was conducted by using a random-effects model, and the pooled effects were expressed with odds ratios (OR) and 95% confidence intervals (95% CI). Probable sources of heterogeneity were identified through meta-regression. Subgroup analysis were based on lesion types, study designs, countries, and so on.
RESULTS
28 studies were ultimately eligible after scanning, and five dietary factors including vitamin D, calcium, folate, fiber and red or processed meat were excerpted. Higher intakes of vitamin D (OR = 0.95, 95%CI:0.90-1.02), calcium (OR = 0.97, 95%CI: 0.91-1.03) and folate (OR = 0.82, 95% CI: 0.6-1.13) were not significantly associated with SP. Fiber intake (OR = 0.90, 95% CI: 0.82-0.99) was a protective factor against SPs. Red meat intake increased the risk of SPs by 30% for the highest versus lowest intakes (OR = 1.30, 95% CI: 1.13-1.51). For different lesion types, higher folate intake was associated with a decreased risk of HPs (OR = 0.59, 95%CI: 0.44-0.79), and higher vitamin D intake decreased the risk of SPs including SSA/P (OR = 0.93, 95%CI: 0.88-0.98).
CONCLUSIONS
Higher dietary fiber intake plays an effective role in preventing SP, while red meat intake is associated with an increased risk of SP. This evidence provides guidance for us to prevent SP from a dietary perspective.
SYSTEMATIC REVIEW REGISTRATION
https://www.crd.york.ac.uk/prospero/display_record.php?, RecordID=340750.
PubMed: 37575321
DOI: 10.3389/fnut.2023.1187539 -
Clinical Nutrition (Edinburgh, Scotland) Jan 2024Accumulating evidence supports the effects of dietary fiber on the risk of non-communicable diseases (NCDs). However, there is no updated systematic review and... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Accumulating evidence supports the effects of dietary fiber on the risk of non-communicable diseases (NCDs). However, there is no updated systematic review and meta-analysis that compares and pools the effect of different types of fiber on mortality.
METHODS
In this systematic review and meta-analysis, all prospective cohort studies that evaluated the relationship between dietary fiber intake and all-cause or cause-specific mortality were included. The PubMed, SCOPUS, and Web of Science databases were searched up to October 2022. Data extraction and quality assessment were performed by two researchers independently. Heterogeneity between studies was assessed using Chi-square based test. Random/fixed effect meta-analysis was used to pool the hazard ratios (HR) or relative risks (RR) and 95 % confidence intervals (CI) for the association between different types of fiber and mortality.
RESULTS
This systematic review included 64 eligible studies, with a total sample size of 3512828 subjects, that investigated the association between dietary fiber intake and mortality from all-cause, cardiovascular disease (CVD), and cancer. Random-effect meta-analysis shows that higher consumption of total dietary fiber, significantly decreased the risk of all-cause mortality, CVD-related mortality, and cancer-related mortality by 23, 26 and 22 % (HR:0.77; 95%CI (0.73,0.82), HR:0.74; 95%CI (0.71,0.77) and HR:0.78; 95%CI (0.68,0.87)), respectively. The consumption of insoluble fiber tended to be more effective than soluble fiber intake in reducing the risk of total mortality and mortality due to CVD and cancer. Additionally, dietary fiber from whole grains, cereals, and vegetables was associated with a reduced risk of all-cause mortality, while dietary fiber from nuts and seeds reduced the risk of CVD-related death by 43 % (HR:0.57; 95 % CI (0.38,0.77)).
CONCLUSION
This comprehensive meta-analysis provides additional evidence supporting the protective association between fiber intake and all-cause and cause-specific mortality rates.
Topics: Humans; Cause of Death; Prospective Studies; Cardiovascular Diseases; Dietary Fiber; Neoplasms; Risk Factors
PubMed: 38011755
DOI: 10.1016/j.clnu.2023.11.005 -
The American Journal of Gastroenterology Oct 2014Irritable bowel syndrome (IBS) and chronic idiopathic constipation (CIC) are functional bowel disorders. Evidence suggests that disturbance in the gastrointestinal... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
Irritable bowel syndrome (IBS) and chronic idiopathic constipation (CIC) are functional bowel disorders. Evidence suggests that disturbance in the gastrointestinal microbiota may be implicated in both conditions. We performed a systematic review and meta-analysis to examine the efficacy of prebiotics, probiotics, and synbiotics in IBS and CIC.
METHODS
MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched (up to December 2013). Randomized controlled trials (RCTs) recruiting adults with IBS or CIC, which compared prebiotics, probiotics, or synbiotics with placebo or no therapy, were eligible. Dichotomous symptom data were pooled to obtain a relative risk (RR) of remaining symptomatic after therapy, with a 95% confidence interval (CI). Continuous data were pooled using a standardized or weighted mean difference with a 95% CI.
RESULTS
The search strategy identified 3,216 citations. Forty-three RCTs were eligible for inclusion. The RR of IBS symptoms persisting with probiotics vs. placebo was 0.79 (95% CI 0.70-0.89). Probiotics had beneficial effects on global IBS, abdominal pain, bloating, and flatulence scores. Data for prebiotics and synbiotics in IBS were sparse. Probiotics appeared to have beneficial effects in CIC (mean increase in number of stools per week=1.49; 95% CI=1.02-1.96), but there were only two RCTs. Synbiotics also appeared beneficial (RR of failure to respond to therapy=0.78; 95% CI 0.67-0.92). Again, trials for prebiotics were few in number, and no definite conclusions could be drawn.
CONCLUSIONS
Probiotics are effective treatments for IBS, although which individual species and strains are the most beneficial remains unclear. Further evidence is required before the role of prebiotics or synbiotics in IBS is known. The efficacy of all three therapies in CIC is also uncertain.
Topics: Abdominal Pain; Adult; Constipation; Dietary Supplements; Humans; Irritable Bowel Syndrome; Prebiotics; Probiotics; Synbiotics; Treatment Outcome
PubMed: 25070051
DOI: 10.1038/ajg.2014.202 -
Nutrition Reviews Jul 2013Dietary fiber has several anticarcinogenic effects and is thought to be protective against esophageal cancer. The aim of this systematic review was to quantify the... (Meta-Analysis)
Meta-Analysis Review
Dietary fiber has several anticarcinogenic effects and is thought to be protective against esophageal cancer. The aim of this systematic review was to quantify the association between dietary fiber and the risk of esophageal cancer by investigating histological subtypes of esophageal cancer and the stage at which fiber may influence the carcinogenic pathway. Systematic search strategies were used to identify relevant studies, and adjusted odds ratios (ORs) were combined using random-effects meta-analyses to assess the risk of cancer when comparing extreme categories of fiber intake. Ten relevant case-control studies were identified within the timeframe searched. Pooled estimates from eight studies of esophageal adenocarcinoma revealed a significant inverse association with the highest fiber intakes (OR 0.66; 95% confidence interval [CI] 0.44-0.98). Two studies also identified protective effects of dietary fiber against Barrett's esophagus. Similar, though nonsignificant, associations were observed when results from five studies of fiber intake and risk of squamous cell carcinoma were combined (OR 0.61; 95%CI 0.31-1.20). Dietary fiber is associated with protective effects against esophageal carcinogenesis, most notably esophageal adenocarcinoma. Potential methods of action include modification of gastroesophageal reflux and/or weight control.
Topics: Adenocarcinoma; Anticarcinogenic Agents; Diet; Dietary Fiber; Esophageal Neoplasms; Humans; Precancerous Conditions; Risk Factors
PubMed: 23815145
DOI: 10.1111/nure.12032 -
PloS One 2018Many interventions have shown effectiveness in reducing the duration of acute diarrhea and gastroenteritis (ADG) in children. Yet, there is lack of comparative efficacy... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Many interventions have shown effectiveness in reducing the duration of acute diarrhea and gastroenteritis (ADG) in children. Yet, there is lack of comparative efficacy of interventions that seem to be better than placebo among which, the clinicians must choose. Our aim was to determine the comparative effectiveness and safety of the pharmacological and nutritional interventions for reducing the duration of ADG in children.
METHODS
Data sources included Medline, Embase, CENTRAL, CINAHL, LILACS, and Global-Health up to May 2017. Eligible trials compared zinc (ZN), vitamin A, micronutrients (MN), probiotics, prebiotics, symbiotics, racecadotril, smectite(SM), loperamide, diluted milk, lactose-free formula(LCF), or their combinations, to placebo or standard treatment (STND), or among them. Two reviewers independently performed screening, review, study selection and extraction. The primary outcome was diarrhea duration. Secondary outcomes were stool frequency at day 2, diarrhea at day 3, vomiting and side effects. We performed a random effects Bayesian network meta-analysis to combine the direct and indirect evidence for each outcome. Mean differences and odds ratio with their credible intervals(CrI) were calculated. Coherence and transitivity assumptions were assessed. Meta-regression, subgroups and sensitivity analyses were conducted to explore the impact of effect modifiers. Summary under the cumulative curve (SUCRA) values with their CrI were calculated. We assessed the evidence quality and classified the best interventions using the Grading of Recommendations, Assessment, Development & Evaluation (GRADE) approach for each paired comparison.
RESULTS
A total of 174 studies (32,430 children) proved eligible. Studies were conducted in 42 countries of which most were low-and middle-income countries (LMIC). Interventions were grouped in 27 categories. Most interventions were better than STND. Reduction of diarrhea varied from 12.5 to 51.1 hours. The combinations Saccharomyces boulardii (SB)+ZN, and SM+ZN were considered the best interventions (i.e., GRADE quality of evidence: moderate to high, substantial superiority to STND, reduction in duration of 35 to 40 hours, and large SUCRA values), while symbiotics (combination of probiotics+prebiotics), ZN, loperamide and combinations ZN+MN and ZN+LCF were considered inferior to the best and better than STND [Quality: moderate to high, superior to STND, and reduction of 17 to 25 hours]. In subgroups analyses, effect of ZN was higher in LMIC and was not present in high-income countries (HIC). Vitamin A, MN, prebiotics, kaolin-pectin, and diluted milk were similar to STND [Quality: moderate to high]. The remainder of the interventions had low to very-low evidence quality. Loperamide was the only intervention with more side effects than STND [Quality: moderate].
DISCUSSION/CONCLUSION
Most interventions analyzed (except vitamin A, micronutrients, prebiotics, and kaolin-pectin) showed evidence of superiority to placebo in reducing the diarrhea. With moderate-to high-quality of evidence, SB+ZN and SM+ZN, demonstrated the best combination of evidence quality and magnitude of effect while symbiotics, loperamide and zinc proved being the best single interventions, and loperamide was the most unsafe. Nonetheless, the effect of zinc, SB+ZN and SM+ZN might only be applied to children in LMIC. Results suggest no further role for studies comparing interventions against no treatment or placebo, or studies testing loperamide, MN, kaolin-pectin, vitamin A, prebiotics and diluted milk.
PROSPERO REGISTRATION
CRD42015023778.
Topics: Antidiarrheals; Bayes Theorem; Child; Diarrhea; Gastroenteritis; Humans; Loperamide; Network Meta-Analysis; Prebiotics; Probiotics; Saccharomyces boulardii; Treatment Outcome; Zinc
PubMed: 30517196
DOI: 10.1371/journal.pone.0207701 -
Medicine Sep 2018The purpose of this study was to conduct a systematic review and meta-analysis of studies investigating the relationship between dietary fiber intake and... (Meta-Analysis)
Meta-Analysis Review
The purpose of this study was to conduct a systematic review and meta-analysis of studies investigating the relationship between dietary fiber intake and subsite-specific colon cancer.The PubMed database was searched to identify relevant cohort studies published from inception to August 2016 in order to examine individually the association between dietary fiber intake and the risk of proximal colon cancer (PCC), and that between dietary fiber intake and the risk of distal colon cancer (DCC). We searched the reference lists of the studies included in our analysis as well as those listed in the published meta-analyses. A random-effects model was used to compute summary risk estimates. Heterogeneity was assessed using I and Q statistics. Publication bias was assessed with the Egger's and Begg's tests, with a P value of P < .10 indicating publication bias. All statistical tests were 2-sided.We identified and included 11 prospective cohort studies in the final meta-analysis. The risks of PCC and DCC among individuals in the highest dietary fiber intake quartile/quintile were 14% (relative risk [RR] = 0.86, 95% confidence interval [CI] = 0.78-0.95) and 21% (RR = 0.79, 95% CI = 0.71-0.87) lower, respectively, than those among individuals with the lowest dietary fiber intake. In a subgroup analysis, the inverse association observed in the sex-based subgroup was apparent only for men with PCC. Dietary fiber intake was inversely associated with DCC for both men and women. In addition, dietary fiber intake appeared to be inversely associated with PCC only in European countries, whereas this association was observed for DCC in both European countries and the United States.Our findings reveal that dietary fiber intake is associated inversely with the risk of both PCC and DCCs.
Topics: Colonic Neoplasms; Diet; Dietary Fiber; Humans; Observational Studies as Topic; Risk Factors
PubMed: 30200062
DOI: 10.1097/MD.0000000000011678 -
The American Journal of Gastroenterology Jun 2018
Topics: Anti-Bacterial Agents; Antidepressive Agents; Behavior Therapy; Constipation; Diarrhea; Diet; Dietary Fiber; Dietary Supplements; Exercise; Humans; Irritable Bowel Syndrome; Mentha piperita; Parasympatholytics; Plant Oils; Prebiotics; Probiotics; Randomized Controlled Trials as Topic; Synbiotics
PubMed: 29950604
DOI: 10.1038/s41395-018-0084-x -
Nutrition Reviews Nov 2017Pancreatic cancer has the highest case fatality rate of all major cancers. (Meta-Analysis)
Meta-Analysis Review
CONTEXT
Pancreatic cancer has the highest case fatality rate of all major cancers.
OBJECTIVE
A systematic review using PRISMA guidelines was conducted to summarize the associations between dietary patterns and risk of pancreatic cancer.
DATA SOURCES
PubMed and Web of Science databases were searched for case-control and cohort studies published up to June 15, 2016.
STUDY SELECTION
Eligible studies included a dietary pattern as exposure and pancreatic cancer incidence or mortality as outcome and reported odds ratios, hazard ratios, or relative risks, along with corresponding 95%CIs.
DATA EXTRACTION
Important characteristics of each study, along with the dietary assessment instrument, the component foods or nutrients included in each dietary pattern or the scoring algorithm of a priori dietary patterns, were presented. For each dietary pattern identified, the estimate of association and the 95%CI comparing the highest versus the lowest category from the model with the most covariate adjustment were reported.
RESULTS
A total of 16 studies were identified. Among the 8 studies that examined data-driven dietary patterns, significant positive associations were found between pancreatic cancer risk and the Animal Products, Starch Rich, and Western dietary patterns, with effect estimates ranging from 1.69 to 2.40. Significant inverse relationships were found between risk of pancreatic cancer and dietary patterns designated as Fruits and Vegetables, Vitamins and Fiber, and Prudent, with effect estimates ranging from 0.51 to 0.55. Eight studies of a priori dietary patterns consistently suggested that improved dietary quality was associated with reduced risk of pancreatic cancer.
CONCLUSIONS
Better diet quality is associated with reduced risk of pancreatic cancer. The associations between dietary patterns and pancreatic cancer were stronger in case-control studies than in cohort studies and were stronger among men than among women.
Topics: Diet; Diet, Western; Dietary Fiber; Female; Fruit; Humans; Incidence; Male; Meat; Pancreatic Neoplasms; Risk; Starch; Vegetables; Vitamins
PubMed: 29025004
DOI: 10.1093/nutrit/nux038 -
Medicina (Kaunas, Lithuania) May 2019: Autism spectrum disorder (ASD) is a complex developmental condition typically characterized by deficits in social and communicative behaviors as well as repetitive...
: Autism spectrum disorder (ASD) is a complex developmental condition typically characterized by deficits in social and communicative behaviors as well as repetitive patterns of behaviors. Despite its prevalence (affecting 0.1% to 1.8% of the global population), the pathogenesis of ASD remains incompletely understood. Patients with ASD are reported to have more frequent gastrointestinal (GI) complaints. There is some anecdotal evidence that probiotics are able to alleviate GI symptoms as well as improve behavioral issues in children with ASD. However, systematic reviews of the effect of prebiotics/probiotics on ASD and its associated symptoms are lacking. : Using the keywords (prebiotics OR probiotics OR microbiota OR gut) AND (autism OR social OR ASD), a systematic literature search was conducted on PubMed, EMBASE, Medline, Clinicaltrials.gov and Google Scholar databases. The inclusion criteria were original clinical trials, published in English between the period 1st January 1988 and 1st February 2019. : A total of eight clinical trials were systematically reviewed. Two clinical trials examined the use of prebiotic and/or diet exclusion while six involved the use of probiotic supplementation in children with ASD. Most of these were prospective, open-label studies. Prebiotics only improved certain GI symptoms; however, when combined with an exclusion diet (gluten and casein free) showed a significant reduction in anti-sociability scores. As for probiotics, there is limited evidence to support the role of probiotics in alleviating the GI or behavioral symptoms in children with ASD. The two available double-blind, randomized, placebo-controlled trials found no significant difference in GI symptoms and behavior. : Despite promising preclinical findings, prebiotics and probiotics have demonstrated an overall limited efficacy in the management of GI or behavioral symptoms in children with ASD. In addition, there was no standardized probiotics regimen, with multiple different strains and concentrations of probiotics, and variable duration of treatments.
Topics: Autism Spectrum Disorder; Gastrointestinal Microbiome; Humans; Prebiotics; Probiotics
PubMed: 31083360
DOI: 10.3390/medicina55050129