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Archives of Iranian Medicine Nov 2017Previous trials have reported beneficial effects of isolated and complex fiber supplements in obesity treatment. However, recommending fiber supplements in obese... (Review)
Review
BACKGROUND
Previous trials have reported beneficial effects of isolated and complex fiber supplements in obesity treatment. However, recommending fiber supplements in obese subjects remains controversial. To the best of our knowledge, no systematic review has updated the data on the effects of fiber supplements on obesity since 2010 and the need exists for a systematic review on this topic. Accordingly, a systematic review was undertaken to summarize the efficacy of different types of fiber supplements as a complementary treatment for weight management.
METHODS
We searched PubMed, Scopus, Cochrane Library and Google Scholar between January 2010 to August 2016 with no language restriction. Considering the inclusion/exclusion criteria and quality assessment score, finally 17 clinical trials met the eligibility criteria and were included.
RESULTS
The present study indicated that the efficacy of various fiber supplements on losing weight is variable. Several mechanisms related to physicochemical properties of fibers such as solubility, fermentability and viscosity rates can be involved in their anti-obesity effects. Dextrin, Mannan (gum Arabic) and pectin-rich fiber (lupin kernel) with no dietary interventions indicated a reduction in body weight and energy intake, while from clinical point of view, their effects were not considerable.
CONCLUSION
Overall, findings indicated that the efficacy of fiber supplements on obesity management is dependent on their contents and physicochemical properties. It seems that fiber supplements with no weight-loss interventions did not have considerable antiobesity effects. However, due to limited studies on each type of fiber, findings should be declared by caution. Additional research is needed on comparison of different fiber supplements in similar conditions to clarify the best type and dosage of fiber supplement as a complementary therapy in obesity management.
Topics: Complementary Therapies; Dietary Fiber; Dietary Supplements; Energy Intake; Humans; Obesity; Randomized Controlled Trials as Topic; Weight Loss
PubMed: 29480736
DOI: No ID Found -
Nutrients Feb 2019Fiber intake is associated with better glycemic control being an important nonpharmacologicaltreatment for diabetes (DM). We hypothesize that a dietary fiber intake can...
Fiber intake is associated with better glycemic control being an important nonpharmacologicaltreatment for diabetes (DM). We hypothesize that a dietary fiber intake can bringbenefits to diabetic kidney disease (DKD), improving renal outcomes. This systematic review aimedto evaluate the effect of dietary fiber (supplemental or dietary pattern rich in fiber) on DKD. Wesearched six databases to identify clinical trials that reported fiber intake and renal outcomes(albuminuria, proteinuria, estimated glomerular filtration rate (eGFR) dialysis) in patients with DM.From 1814 studies, 48 papers were fully evaluated. In the end, seven trials (161 patients, aged 58.3years, 49% females) were included. The studies were organized into three categories (vegetarian,Dietary Approaches to Stop Hypertension (DASH) diet, and fiber supplement), two evaluatedsupplements and five dietary patterns. Vegetarian diet reduced albuminuria in three trials, two inpatients with type 1 DM and one in patients with type 2 DM; and one study demonstrated a change inthe eGFR in type 1 DM. The individual quality of the studies was low/uncertain. A vegetarian dietarypattern may have a beneficial effect on these renal outcomes. However, the individual effect of theintake of fiber on DKD not was possible to be evaluated.
Topics: Clinical Trials as Topic; Diabetic Nephropathies; Diet; Dietary Fiber; Dietary Supplements; Female; Humans; Kidney; Male; Middle Aged; Treatment Outcome
PubMed: 30736343
DOI: 10.3390/nu11020347 -
Beneficial Microbes Dec 2020This review aims to present a comprehensive state-of-the-art analysis of the bidirectional crosstalk between gut microbiota and the central nervous system (CNS). The... (Meta-Analysis)
Meta-Analysis
This review aims to present a comprehensive state-of-the-art analysis of the bidirectional crosstalk between gut microbiota and the central nervous system (CNS). The literature concerning the potential effects of gut microbiota on psychiatric disorders through neural pathways comprising the 'gut-brain axis' were gathered. In addition, the influence of probiotics and prebiotics and dairy-rich diets combined with the intake of probiotics and prebiotics on gut microbiota and the subsequent relationship with brain function was reviewed. However, a meta-analysis on the effectiveness of probiotic supplementation in psychiatric disorders is lacking. Therefore, a systematic search of PubMed, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov databases from January 1969 to December 2019 was conducted. It led to the identification of a total of 844 research articles. Of these, a total of 23 studies met the meta-analysis criteria. Statistical analysis revealed that there was no significant difference in the symptoms of schizophrenia, stress, and anxiety between probiotic and placebo groups, post-intervention. Probiotic administration reduced depressive symptoms among patients with depression in a statistically significant manner (standardised mean difference (SMD) = -0.87; 95% confidence interval (95% confidence interval): -1.66, -0.99; =0.03). Further evidence from larger and more rigorous studies with longer duration of probiotic administration, as well as well-defined populations, homogenous probiotic intervention and outcome measures, are needed to clarify the potential therapeutic effects of probiotics on psychiatric symptoms. Based on the current literature, it seems that not all probiotic-/prebiotic-/dairy-rich diet-based treatments exhibited a psychobiotic effect on the CNS. Among the parameters determining the success of the given treatment, the most significant were probiotic composition (multi-strain formulation), the quantity of ingested psychobiotics and the duration of the study.
Topics: Anxiety Disorders; Brain; Diet; Diet Therapy; Gastrointestinal Microbiome; Humans; Prebiotics; Probiotics; Schizophrenia; Stress, Psychological
PubMed: 33191776
DOI: 10.3920/BM2020.0063 -
The American Journal of Clinical... Feb 2020The role of dietary fiber in obesity management remains debatable. Evidence suggests that intake of viscous fiber may have the potential to facilitate weight loss. (Meta-Analysis)
Meta-Analysis
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.
Topics: Body Weight; Diet, Reducing; Dietary Fiber; Energy Intake; Humans
PubMed: 31897475
DOI: 10.1093/ajcn/nqz292 -
Nutrition Reviews Nov 2023Dietary fibers hold potential to influence depressive and anxiety outcomes by modulating the microbiota-gut-brain axis, which is increasingly recognized as an underlying...
CONTEXT
Dietary fibers hold potential to influence depressive and anxiety outcomes by modulating the microbiota-gut-brain axis, which is increasingly recognized as an underlying factor in mental health maintenance.
OBJECTIVE
Evidence for the effects of fibers on depressive and anxiety outcomes remains unclear. To this end, a systematic literature review and a meta-analysis were conducted that included observational studies and randomized controlled trials (RCTs).
DATA SOURCES
The PubMed, Embase, CENTRAL, CINAHL, and PsychINFO databases were searched for eligible studies.
DATA EXTRACTION
Study screening and risk-of-bias assessment were conducted by 2 independent reviewers.
DATA ANALYSIS
Meta-analyses via random effects models were performed to examine the (1) association between fiber intake and depressive and anxiety outcomes in observational studies, and (2) effect of fiber intervention on depressive and anxiety outcomes compared with placebo in RCTs. A total of 181 405 participants were included in 23 observational studies. In cross-sectional studies, an inverse association was observed between fiber intake and depressive (Cohen's d effect size [d]: -0.11; 95% confidence interval [CI]: -0.16, -0.05) and anxiety (d = -0.25; 95%CI, -0.38, -0.12) outcomes. In longitudinal studies, there was an inverse association between fiber intake and depressive outcomes (d = -0.07; 95%CI, -0.11, -0.04). In total, 740 participants were included in 10 RCTs, all of whom used fiber supplements. Of note, only 1 RCT included individuals with a clinical diagnosis of depression. No difference was found between fiber supplementation and placebo for depressive (d = -0.47; 95%CI, -1.26, 0.31) or anxiety (d = -0.30; 95%CI, -0.67, 0.07) outcomes.
CONCLUSION
Although observational data suggest a potential benefit for higher fiber intake for depressive and anxiety outcomes, evidence from current RCTs does not support fiber supplementation for improving depressive or anxiety outcomes. More research, including RCTs in clinical populations and using a broad range of fibers, is needed.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO registration no. CRD42021274898.
PubMed: 38007616
DOI: 10.1093/nutrit/nuad143 -
Oncotarget Dec 2016Current evidence from randomised controlled trials on the effects of dietary fibre intake on breast cancer risk is inconsistent. We conducted a meta-analysis to... (Meta-Analysis)
Meta-Analysis Review
Current evidence from randomised controlled trials on the effects of dietary fibre intake on breast cancer risk is inconsistent. We conducted a meta-analysis to determine the effectiveness of dietary fibre intake in reducing breast cancer risk. We searched for prospective and case-control studies on dietary fibre intake and breast cancer risk in the English language through March 2016. Twenty-four epidemiologic studies obtained through the PubMed, Embase, Web of Science, and Cochrane Library databases were systematically reviewed. A random-effects model was used to compute the pooled risk estimates by extracting the risk estimate of the highest and lowest reported categories of intake from each study. The meta-analyses showed a 12% decrease in breast cancer risk with dietary fibre intake. The association between dietary fibre intake and breast cancer risk was significant when stratified according to Jadad scores, study types, and menopause status. Dose-response analysis showed that every 10 g/d increment in dietary fibre intake was associated with a 4% reduction in breast cancer risk, and little evidence of publication bias was found. Thus, dietary fibre consumption is significantly associated with a reduced risk of breast cancer, particularly in postmenopausal women.
Topics: Adult; Aged; Aged, 80 and over; Breast Neoplasms; Diet, Healthy; Dietary Fiber; Female; Humans; Life Style; Middle Aged; Postmenopause; Protective Factors; Recommended Dietary Allowances; Risk Assessment; Risk Factors; Risk Reduction Behavior
PubMed: 27829237
DOI: 10.18632/oncotarget.13140 -
Molecular Nutrition & Food Research Jan 2015The present meta-analysis aimed to investigate fiber consumption and all-cause mortality, and cause-specific mortality. MEDLINE and web of science database were searched... (Meta-Analysis)
Meta-Analysis Review
The present meta-analysis aimed to investigate fiber consumption and all-cause mortality, and cause-specific mortality. MEDLINE and web of science database were searched for cohort studies published from inception to August 2014. Studies were included if they provided a hazard ratio (HR) and corresponding 95% CI for mortality in relation to fiber consumption.We found that, compared with those who consumed lowest fiber, for individuals who ate highest fiber, mortality rate was lower by 23% (HR, 0.77; 95% CI, 0.72-0.81) for CVD, by 17% (HR, 0.83; 95% CI, 0.74-0.91) for cancer, by 23% (HR, 0.77; 95% CI, 0.73-0.81) for all-cause mortality. For each 10 g/day increase in fiber intake, the pooled HR was estimated to be 0.89 (95% CI, 0.86-0.93) for all-cause mortality, 0.80 (95% CI, 0.72-0.88) for CHD mortality, and 0.66 (95% CI, 0.40-0.92) for IHD mortality, 0.91 (95% CI, 0.88-0.94) for cancer. Dietary fiber and CVD mortality showed a strong dose-response relation. Apparently, fiber consumption is inversely associated with all-cause mortality and CVD, IHD, cancer mortality.
Topics: Cardiovascular Diseases; Databases, Factual; Dietary Fiber; Humans; Neoplasms; Observational Studies as Topic; Risk Factors
PubMed: 25382817
DOI: 10.1002/mnfr.201400449 -
The Lancet. Gastroenterology &... Feb 2020Although novel therapies for irritable bowel syndrome (IBS) continue to be developed, many doctors rely on more established, traditional therapies as first-line or...
BACKGROUND
Although novel therapies for irritable bowel syndrome (IBS) continue to be developed, many doctors rely on more established, traditional therapies as first-line or second-line treatment options. These therapies include soluble fibre (eg, ispaghula husk), antispasmodic drugs, peppermint oil, and gut-brain neuromodulators (including tricyclic antidepressants, selective serotonin reuptake inhibitors, or α-2-δ calcium channel subunit ligands). However, the relative efficacy of traditional treatments in patients with IBS is unclear because there have been few head-to-head randomised controlled trials (RCTs). We aimed to compare and rank the efficacy of traditional therapies in patients with IBS to help inform clinical decisions.
METHODS
For this systematic review and network meta-analysis, we searched MEDLINE, Embase, Embase Classic, and the Cochrane Central Register of Controlled Trials from inception to week 2 of August 2019; ClinicalTrials.gov for unpublished trials or supplementary data published up to Aug 18, 2019; and gastroenterology conference proceedings for study abstracts published between 2001 and Aug 18, 2019. We included RCTs that compared any of these treatments with each other (head-to-head trials) or with placebo, in which the efficacy of soluble fibre, antispasmodic drugs, peppermint oil, or gut-brain neuromodulators was assessed in adults (aged at least 18 years) with IBS of any subtype after 4-12 weeks of treatment. Only RCTs reporting a dichotomous assessment of overall response to therapy, in terms of either improvement in global IBS symptoms or improvement in abdominal pain, were included. The efficacy and safety of all treatments were reported as a pooled relative risk (RR) with 95% CIs to summarise the effect of each comparison tested, and treatments were ranked according to their P-score.
FINDINGS
Our search identified 5863 references, of which 81 were screened for eligibility. 51 RCTs with data from 4644 patients were eligible for inclusion in our analysis, but only 13 of these trials were at low risk of bias. Based on an endpoint of failure to achieve improvement in global IBS symptoms at 4-12 weeks, peppermint oil capsules were ranked first for efficacy (RR 0·63, 95% CI 0·48-0·83, P-score 0·84) and tricyclic antidepressants were ranked second (0·66, 0·53-0·83, P-score 0·77). For failure to achieve an improvement in global IBS symptoms at 4-12 weeks, there were no significant differences between active treatments after direct or indirect comparisons. For failure to achieve improvement in abdominal pain at 4-12 weeks, tricyclic antidepressants were ranked first for efficacy (0·53, 0·34-0·83, P-score 0·87); however, this result was based on data from only four RCTs involving 92 patients. For failure to achieve an improvement in abdominal pain, none of the active treatments showed superior efficacy upon indirect comparison. Tricyclic antidepressants were more likely than placebo to lead to adverse events (1·59, 1·26-2·06, P-score 0·16).
INTERPRETATION
In this network meta-analysis of RCTs of soluble fibre, antispasmodic drugs, peppermint oil, and gut-brain neuromodulators for IBS, few of which were judged as being at a low risk of bias, peppermint oil was ranked first for efficacy when global symptoms were used as the outcome measure, and tricyclic antidepressants were ranked first for efficacy when abdominal pain was used as the outcome measure. However, because of the lack of methodological rigour of some RCTs analysed in our study, there is likely to be considerable uncertainty around these findings. In addition, because treatment duration in most included trials was 4-12 weeks, the long-term relative efficacy of these treatments is unknown.
FUNDING
None.
Topics: Brain; Dietary Fiber; Humans; Intestinal Mucosa; Irritable Bowel Syndrome; Network Meta-Analysis; Neurotransmitter Agents; Parasympatholytics; Treatment Outcome
PubMed: 31859183
DOI: 10.1016/S2468-1253(19)30324-3 -
Nutrients Aug 2020Nutritional guidelines suggest specific energy and protein requirements for patients with cancer. However, cancer patients, often malnourished, use self-made or...
Nutritional guidelines suggest specific energy and protein requirements for patients with cancer. However, cancer patients, often malnourished, use self-made or web-based diets to ameliorate the prognosis of their disease. This review aimed to investigate the associations between post-diagnostic diet and prognostic outcomes in cancer patients. A systematic literature search was performed in Pubmed and Web of Science databases from inception to 30 October 2019, based on fixed inclusion and exclusion criteria. The risk of bias was assessed. A total of 29 prospective studies was identified. Breast ( = 11), colorectal ( = 9), prostate ( = 8) cancers are the most studied. Low- fat diet, healthy quality diet, regular consumption of fiber such as vegetables and high-quality protein intake are beneficial while Western diet (WD) and high consumption of saturated fats could be associated with a higher risk of mortality. Bladder ( = 1), gynecological ( = 1), lung, stomach, and pancreatic cancers still remain almost unexplored. This systematic review suggested that detrimental dietary patterns such as WD should be avoided but none of the food categories (meat, dairy products) should be eliminated in cancer patients' diet. Further large prospective studies are needed to assess the role of post-diagnostic diet in patients with cancer.
Topics: Cohort Studies; Dairy Products; Diet; Diet, Fat-Restricted; Diet, Western; Dietary Fats; Dietary Fiber; Disease Progression; Feeding Behavior; Female; Gastrointestinal Microbiome; Humans; Male; Meat; Neoplasms; Prognosis; Prospective Studies; Vegetables
PubMed: 32764484
DOI: 10.3390/nu12082345 -
Frontiers in Nutrition 2022Although several meta-analyses have revealed the beneficial effects of dietary fiber intake on human health, some have reported inconsistent findings. The purpose of...
Although several meta-analyses have revealed the beneficial effects of dietary fiber intake on human health, some have reported inconsistent findings. The purpose of this work was to perform an umbrella meta-analysis to evaluate the relevant evidence and elucidate the effect of dietary fiber intake on glycemic control, lipid profiles, systematic inflammation, and blood pressure. Eligible studies were searched in several electronic databases, including Web of Science, PubMed, Scopus, and the Cochrane Library, up to March 2022. A total of 52 meta-analyses involving 47,197 subjects were identified to assess the pooled effect size. Overall, higher dietary fiber intake was significantly associated with reductions in parameters involving glycemic control, including fasting plasma glucose (ES = -0.55, 95% CI: -0.73, -0.38, < 0.001), fasting plasma insulin (ES = -1.22, 95% CI: -1.63, -0.82, < 0.001), homeostasis model assessment of insulin resistance (HOMA-IR) (ES = -0.43, 95% CI: -0.60, -0.27, < 0.001), and glycosylated hemoglobin (HbA1c) (ES = -0.38, 95% CI: -0.50, -0.26, < 0.001). In terms of lipid profiles, higher dietary fiber intake was associated with significant reductions in the serum level of total cholesterol (ES = -0.28, 95% CI: -0.39, -0.16, < 0.001) and low-density lipoprotein cholesterol (ES = -0.25, 95% CI: -0.34, -0.16, < 0.001), but not triglycerides (ES = -0.001, 95% CI: -0.006, 0.004, = 0.759) and high-density lipoprotein cholesterol (ES = -0.002, 95% CI: -0.004, 0.000, = 0.087). Higher dietary fiber intake was also significantly associated with improved tumor necrosis factor-alpha serum levels (ES = -0.78, 95% CI: -1.39, -0.16, = 0.013), while no significant effect was observed for C-reactive protein (ES = -0.14, 95% CI: -0.33, 0.05, = 0.156). Finally, blood pressure was also significantly improved following higher dietary fiber intake (systolic blood pressure: ES = -1.72, 95% CI: -2.13, -1.30, < 0.001; diastolic blood pressure: ES = -0.67, 95% CI: -0.96, -0.37, < 0.001). Subgroup analysis revealed that the study population and type of dietary fiber could be partial sources of heterogeneity. In conclusion, the present umbrella meta-analysis provides evidence for the role of dietary fiber supplementation in the improvement of established cardiovascular risk factors.
PubMed: 36172520
DOI: 10.3389/fnut.2022.972399