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Cureus Sep 2023Cardiovascular diseases (CVDs) are a significant global health concern, necessitating effective preventive measures. Dietary fiber has gained attention as a potential... (Review)
Review
Cardiovascular diseases (CVDs) are a significant global health concern, necessitating effective preventive measures. Dietary fiber has gained attention as a potential cardiovascular risk factor modifier. Although its effects on various CVD risk markers such as cholesterol levels and blood glucose levels have been explored, the relationship between dietary fiber and blood pressure remains somewhat elusive across the different studies conducted worldwide. In this systematic review, we conducted an extensive analysis of recent research from a global perspective, aiming to elucidate the relationship between dietary fiber intake and blood pressure. From an initial pool of more than 24,500 articles retrieved from PubMed and Google Scholar, we rigorously selected 11 studies published in the last decade (post-2013) to ensure up-to-date insights. These selected studies encompass diverse populations from different regions worldwide, allowing for a comprehensive global assessment. Our analysis revealed a positive overall impact of increased dietary fiber intake on blood pressure levels. Despite variations in study parameters, consistent trends were observed across multiple continents. This systematic review underscores the potential of dietary fiber intake to reduce blood pressure and improve cardiovascular health globally. This review serves as a global analysis and updates on the developments about the potential association between dietary fiber and blood pressure levels. While the findings are promising, further research is essential to elucidate underlying mechanisms and ensure global consistency. Collaborative efforts and ongoing investigation are crucial for harnessing the cardiovascular benefits of dietary fiber and addressing the worldwide burden of hypertension.
PubMed: 37900495
DOI: 10.7759/cureus.46116 -
Neurogastroenterology and Motility Jan 2024Numerous individual and environmental factors including diet may play an important role in the pathophysiology of irritable bowel syndrome (IBS). It is unclear to what... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Numerous individual and environmental factors including diet may play an important role in the pathophysiology of irritable bowel syndrome (IBS). It is unclear to what degree dietary intake is affected in individuals with IBS. We aimed to perform a systematic review and meta-analysis to summarize dietary intake of adults with IBS and to compare dietary intake between adults with IBS and non-IBS controls.
METHODS
Ovid MEDLINE, Embase, Cochrane, CINAHL, and Scopus were searched through February 2023 for clinical trials and observational studies measuring usual diet in adults with IBS. Pooled weighted averages were estimated for total energy, macronutrient, and micronutrient data. Mean differences (MD) in nutrient intake were estimated for adults with IBS versus non-IBS controls using a random effects model. Heterogeneity was assessed by the inconsistency index (I2).
KEY RESULTS
Sixty-three full-text articles were included in the review of which 29 studies included both IBS and control subjects. Nutrients not meeting the recommended intake level for any dietary reference values in the IBS population were fiber and vitamin D. Meta-regression by female proportion was positively correlated with total fat intake and negatively correlated with carbohydrate intake. Comparisons between participants with IBS and controls showed significantly lower fiber intake in participants with IBS with high heterogeneity (MD: -1.8; 95% CI: -3.0, -0.6; I2 = 85%).
CONCLUSIONS AND INFERENCES
This review suggests that fiber and vitamin D intake is suboptimal in IBS; however, overall dietary intake does not appear to be comprised. Causes and consequences of reduced fiber in IBS deserve further study. Results of this systematic review and meta-analysis suggest that fiber and vitamin D intake is suboptimal in IBS. However, overall intake of other macro- and micronutrients does not appear to be compromised. Causes and consequences of reduced fiber and Vitamin D intake in IBS deserve further study.
Topics: Adult; Humans; Female; Irritable Bowel Syndrome; Diet; Eating; Energy Intake; Vitamin D
PubMed: 37897138
DOI: 10.1111/nmo.14698 -
Nutrients Oct 2023Health authorities increasingly recommend sustainable and healthy diets rich in plant foods and with moderate amounts of animal foods. However, there are concerns about... (Review)
Review
Health authorities increasingly recommend sustainable and healthy diets rich in plant foods and with moderate amounts of animal foods. However, there are concerns about whether such diets can meet all nutrient requirements, especially in children and adolescents, who have relatively high nutrient needs for growth and development. Therefore, we aimed to evaluate the nutrient intake and status of children and adolescents (2-18 y) consuming plant-based (i.e., vegetarian and vegan) diets compared to those of meat-eating children following a systematic literature review of studies published between 2000 and 2022. Mean intake and status data of nutrients were calculated across studies and benchmarked to dietary reference values and cut-off values for nutrient deficiencies. A total of 30 studies were included (15 in children 2-5 y, 24 in children 6-12 y, and 11 in adolescents 13-18 y). In all diets, there were risks of inadequate intakes of vitamin D and calcium. Children consuming meat had a risk of inadequate folate and vitamin E intake; and mean fiber, SAFA, and PUFA intakes were not in line with the recommendations. Children consuming plant-based diets risked inadequate vitamin B12, iron, and zinc intakes. In contrast to vegans, vegetarian children may not meet the recommended intakes of fiber, SAFA, and possibly PUFA, but their mean intakes were more favorable than in meat-eating children. Although the data are limited and need further validation, our findings indicate that there are risks of nutritional inadequacies in all diet groups. Therefore, increasing consumption of a variety of plant-based foods, in combination with food fortification and supplementation where needed, is recommended for children and adolescents to have sustainable and nutritionally adequate diets.
Topics: Animals; Humans; Child; Adolescent; Diet; Energy Intake; Meat; Eating; Diet, Vegan; Diet, Vegetarian
PubMed: 37892416
DOI: 10.3390/nu15204341 -
The Cochrane Database of Systematic... Oct 2023Chronic kidney disease (CKD) is a major public health problem affecting 13% of the global population. Prior research has indicated that CKD is associated with gut... (Review)
Review
BACKGROUND
Chronic kidney disease (CKD) is a major public health problem affecting 13% of the global population. Prior research has indicated that CKD is associated with gut dysbiosis. Gut dysbiosis may lead to the development and/or progression of CKD, which in turn may in turn lead to gut dysbiosis as a result of uraemic toxins, intestinal wall oedema, metabolic acidosis, prolonged intestinal transit times, polypharmacy (frequent antibiotic exposures) and dietary restrictions used to treat CKD. Interventions such as synbiotics, prebiotics, and probiotics may improve the balance of the gut flora by altering intestinal pH, improving gut microbiota balance and enhancing gut barrier function (i.e. reducing gut permeability).
OBJECTIVES
This review aimed to evaluate the benefits and harms of synbiotics, prebiotics, and probiotics for people with CKD.
SEARCH METHODS
We searched the Cochrane Kidney and Transplant Register of Studies up to 9 October 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.
SELECTION CRITERIA
We included randomised controlled trials (RCTs) measuring and reporting the effects of synbiotics, prebiotics, or probiotics in any combination and any formulation given to people with CKD (CKD stages 1 to 5, including dialysis and kidney transplant). Two authors independently assessed the retrieved titles and abstracts and, where necessary, the full text to determine which satisfied the inclusion criteria.
DATA COLLECTION AND ANALYSIS
Data extraction was independently carried out by two authors using a standard data extraction form. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) or standardised mean difference (SMD) and 95% CI for continuous outcomes. The methodological quality of the included studies was assessed using the Cochrane risk of bias tool. Data entry was carried out by one author and cross-checked by another. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.
MAIN RESULTS
Forty-five studies (2266 randomised participants) were included in this review. Study participants were adults (two studies in children) with CKD ranging from stages 1 to 5, with patients receiving and not receiving dialysis, of whom half also had diabetes and hypertension. No studies investigated the same synbiotic, prebiotic or probiotic of similar strains, doses, or frequencies. Most studies were judged to be low risk for selection bias, performance bias and reporting bias, unclear risk for detection bias and for control of confounding factors, and high risk for attrition and other biases. Compared to prebiotics, it is uncertain whether synbiotics improve estimated glomerular filtration rate (eGFR) at four weeks (1 study, 34 participants: MD -3.80 mL/min/1.73 m², 95% CI -17.98 to 10.38), indoxyl sulfate at four weeks (1 study, 42 participants: MD 128.30 ng/mL, 95% CI -242.77 to 499.37), change in gastrointestinal (GI) upset (borborymgi) at four weeks (1 study, 34 participants: RR 15.26, 95% CI 0.99 to 236.23), or change in GI upset (Gastrointestinal Symptom Rating Scale) at 12 months (1 study, 56 participants: MD 0.00, 95% CI -0.27 to 0.27), because the certainty of the evidence was very low. Compared to certain strains of prebiotics, it is uncertain whether a different strain of prebiotics improves eGFR at 12 weeks (1 study, 50 participants: MD 0.00 mL/min, 95% CI -1.73 to 1.73), indoxyl sulfate at six weeks (2 studies, 64 participants: MD -0.20 μg/mL, 95% CI -1.01 to 0.61; I² = 0%) or change in any GI upset, intolerance or microbiota composition, because the certainty of the evidence was very low. Compared to certain strains of probiotics, it is uncertain whether a different strain of probiotic improves eGFR at eight weeks (1 study, 30 participants: MD -0.64 mL/min, 95% CI -9.51 to 8.23; very low certainty evidence). Compared to placebo or no treatment, it is uncertain whether synbiotics improve eGFR at six or 12 weeks (2 studies, 98 participants: MD 1.42 mL/min, 95% CI 0.65 to 2.2) or change in any GI upset or intolerance at 12 weeks because the certainty of the evidence was very low. Compared to placebo or no treatment, it is uncertain whether prebiotics improves indoxyl sulfate at eight weeks (2 studies, 75 participants: SMD -0.14 mg/L, 95% CI -0.60 to 0.31; very low certainty evidence) or microbiota composition because the certainty of the evidence is very low. Compared to placebo or no treatment, it is uncertain whether probiotics improve eGFR at eight, 12 or 15 weeks (3 studies, 128 participants: MD 2.73 mL/min, 95% CI -2.28 to 7.75; I² = 78%), proteinuria at 12 or 24 weeks (1 study, 60 participants: MD -15.60 mg/dL, 95% CI -34.30 to 3.10), indoxyl sulfate at 12 or 24 weeks (2 studies, 83 participants: MD -4.42 mg/dL, 95% CI -9.83 to 1.35; I² = 0%), or any change in GI upset or intolerance because the certainty of the evidence was very low. Probiotics may have little or no effect on albuminuria at 12 or 24 weeks compared to placebo or no treatment (4 studies, 193 participants: MD 0.02 g/dL, 95% CI -0.08 to 0.13; I² = 0%; low certainty evidence). For all comparisons, adverse events were poorly reported and were minimal (flatulence, nausea, diarrhoea, abdominal pain) and non-serious, and withdrawals were not related to the study treatment.
AUTHORS' CONCLUSIONS
We found very few studies that adequately test biotic supplementation as alternative treatments for improving kidney function, GI symptoms, dialysis outcomes, allograft function, patient-reported outcomes, CVD, cancer, reducing uraemic toxins, and adverse effects. We are not certain whether synbiotics, prebiotics, or probiotics are more or less effective compared to one another, antibiotics, or standard care for improving patient outcomes in people with CKD. Adverse events were uncommon and mild.
Topics: Adult; Child; Humans; Synbiotics; Prebiotics; Dysbiosis; Indican; Uremic Toxins; Renal Insufficiency, Chronic; Probiotics
PubMed: 37870148
DOI: 10.1002/14651858.CD013631.pub2 -
Frontiers in Nutrition 2023To conduct a systematic review and meta-analysis of prospective cohort studies to investigate the association between total, vegetable, fruit, cereal, soluble and...
Dietary intake of total vegetable, fruit, cereal, soluble and insoluble fiber and risk of all-cause, cardiovascular, and cancer mortality: systematic review and dose-response meta-analysis of prospective cohort studies.
OBJECTIVES
To conduct a systematic review and meta-analysis of prospective cohort studies to investigate the association between total, vegetable, fruit, cereal, soluble and insoluble fiber intake and risk of all causes, cardiovascular disease (CVD), and cancer mortality and quantitatively assess the dose-response relation.
METHODS
Eligible studies were identified by searching PubMed, Embase and Web of science before August 2023. Random effects models were used to calculate summary relative risk (RR) and 95% confidence intervals (CI) and restricted cubic splines to model the linear/non-linear association.
RESULTS
The summary RR for all-cause, CVD and cancer mortality of dietary fiber was 0.90 (95% CI: 0.86,0.93), 0.87 (0.84,0.91), 0.91 (0.88,0.93), respectively. Significant association was observed for all-cause and CVD mortality with fruit, vegetable cereal and soluble fiber intake and cancer mortality with cereal fiber intake. No significant association was found for insoluble fiber, vegetable or fruit fiber intake and cancer mortality. Dose-response analysis showed a significant non-linear relation of dietary fiber intake with all-cause mortality, and linear relation for others.
CONCLUSIONS
Higher dietary fiber including different type and food sources of fiber intake were associated with lower risk of mortality. Our findings provide more comprehensive evidence on dietary fiber intake with mortality.
SYSTEMATIC REVIEW REGISTRATION
https://www.crd.york.ac.uk/prospero, identifier: CRD42022338837.
PubMed: 37854351
DOI: 10.3389/fnut.2023.1153165 -
Nutrition Journal Oct 2023Pervious epidemiologic evidence indicates that soluble fiber is protective against hypertention: however, randomized controlled trials (RCTs) have presented varying... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
Pervious epidemiologic evidence indicates that soluble fiber is protective against hypertention: however, randomized controlled trials (RCTs) have presented varying results. In the present study, we aimed to conduct a systematic review and dose-response meta-analysis to summarize published RCTs which assess the effect of soluble fiber supplementation on systolic blood pressure (SBP) and diastolic blood pressure (DBP).
METHODS
Scopus, PubMed, and ISI Web of Sciences were searched to identify relevant studies up to Aug 2022. We estimated the change in blood pressure for each 5 g/d increment in soluble fiber supplementation in each trial and then calculated the weighted mean difference (WMD) and 95%CI using a random-effects model. We estimated dose-dependent effects using a dose-response meta-analysis of differences in means. The risk of bias for study was assessed using the Cochrane tool. Publication bias was evaluated via funnel plot and Begg's test and Egger's test.
RESULTS
Eighty-three eligible studies with total sample size of 5,985 participants were included in the meta-analysis. Soluble fiber supplementation significantly decreased SBP (WMD: -1.36 mmHg, 95% CI: -2.13 to -0.60, P < 0.001; I = 47.1%, P < 0.001) and DBP (WMD: -0.72 mmHg, 95% CI: -1.26 to -0.18, P = 0.009; I = 45.4%, P < 0.001). Each 5 g/d increment in soluble fiber supplementation had a significant reduction in SBP (WMD: -0.54 mmHg; 95%CI: -0.86, -0.22, P = 0.001; I = 52.2, P < 0.001) and DBP (WMD: -0.28 mmHg; 95%CI: -0.49, -0.80, P = 0.007; I = 43.1%, P < 0.001). The levels of SBP decreased proportionally with the increase in soluble fiber supplementation up to 20 g/d (MD: -1.79 mmHg, 95%CI: -2.86, -0.71).
CONCLUSION
Current evidence indicated the beneficial effect of soluble fiber supplementation on blood pressure. Our findings suggest that soluble fiber supplementation could contribute to the management of hypertension and the reduction of cardiovascular disease risk.
Topics: Adult; Humans; Blood Pressure; Dietary Supplements; Randomized Controlled Trials as Topic; Hypertension; Bias
PubMed: 37833676
DOI: 10.1186/s12937-023-00879-0 -
Reviews in Endocrine & Metabolic... Feb 2024In recent years, a growing number of studies have examined the relationship between thyroid pathophysiology and intestinal microbiota composition. The reciprocal... (Review)
Review
In recent years, a growing number of studies have examined the relationship between thyroid pathophysiology and intestinal microbiota composition. The reciprocal influence between these two entities has been proven so extensive that some authors coined the term "gut-thyroid axis". However, since some papers reported conflicting results, several aspects of this correlation need to be clarified. This systematic review was conceived to achieve more robust information about: 1)the characteristics of gut microbiota composition in patients with the more common morphological, functional and autoimmune disorders of the thyroid; 2)the influence of gut microbial composition on micronutrients that are essential for the maintenance of thyroid homeostasis; 3)the effect of probiotics, prebiotics and synbiotics, some of the most popular over-the-counter products, on thyroid balance; 4)the opportunity to use specific dietary advice. The literature evaluation was made by three authors independently. A five steps strategy was a priori adopted. After duplicates removal, 1106 records were initially found and 38 reviews were finally included in the analysis. The systematic reviews of reviews found that: 1) some significant variations characterize the gut microbiota composition in patients with thyroid disorders. However, geographical clustering of most of the studies prevents drawing definitive conclusions on this topic; 2) the available knowledge about the effect of probiotics and synbiotics are not strong enough to suggest the routine use of these compounds in patients with thyroid disorders; 3) specific elimination nutrition should not be routine suggested to patients, which, instead have to be checked for possible micronutrients and vitamins deficiency, often owed to gastrointestinal autoimmune comorbidities.
Topics: Humans; Thyroid Gland; Prebiotics; Probiotics; Microbiota; Micronutrients
PubMed: 37824030
DOI: 10.1007/s11154-023-09839-9 -
Journal of Medical Microbiology Sep 2023Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that affects the quality of life of numerous people worldwide. The therapeutic role of gut... (Meta-Analysis)
Meta-Analysis
Efficacy of probiotics, prebiotics and synbiotics in irritable bowel syndrome: a systematic review and meta-analysis of randomized, double-blind, placebo-controlled trials.
Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that affects the quality of life of numerous people worldwide. The therapeutic role of gut microbiota modulation in IBS remains controversial. We aimed to assess the efficacy of probiotics, prebiotics or synbiotics in patients with IBS. We searched MEDLINE and EMBASE up to 1 August 2023, to identify the randomized, double-blind, placebo-controlled trials investigating the effectiveness of probiotics, prebiotics or synbiotics among patients with IBS. Pooled analyses of the effects of probiotics in relieving IBS symptoms were calculated using a random-effects model. Further subgroup analyses were performed by different genera, doses and duration of treatment. Our final analysis included 52 trials involving 6289 IBS patients. Probiotics significantly increased the overall response rate (RR:1.64; <0.00001), subjective relief rate (RR:1.50; =0.0002) and abdominal pain relief rate (RR:1.69; <0.00001). As for specific genera, mixed probiotics (RR:1.41; =0.0001), (RR:1.76; <0.00001), (RR:1.97; =0.0004) and (RR:1.31; =0.0004) markedly relieved IBS symptoms. Mixed probiotics (RR:1.31; =0.005), (RR:2.22; =0.04) and (RR:1.62; <0.0001) elevated patients' subjective relief rate. Besides, probiotics effectively relieved the abdominal pain in IBS patients (RR:1.69; <0.00001). Probiotics appeared to show a remarkable beneficial role at a dose of 10 c.f.u./day or above (RR:1.662; <0.0001) and started to work at 4 weeks (RR 1.72; <0.00001). Efficacy of prebiotics and synbiotics in IBS remained uncertain, due to the deficiency of available RCTs. Probiotics have a therapeutic role in IBS. However, the effect of different probiotics varies. The minimal effective dose of probiotics may be 10 c.f.u./day. With appropriate probiotic formula, the therapeutic effect can occur at 4 weeks. These data provide a basis for further research on the optimal probiotic therapy in IBS.
Topics: Humans; Prebiotics; Synbiotics; Irritable Bowel Syndrome; Quality of Life; Probiotics; Lactobacillus; Abdominal Pain; Randomized Controlled Trials as Topic
PubMed: 37772692
DOI: 10.1099/jmm.0.001758 -
Nutrients Sep 2023Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder characterized by abdominal pain, bloating, and changes in bowel habits. Various dietary factors... (Review)
Review
BACKGROUND
Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder characterized by abdominal pain, bloating, and changes in bowel habits. Various dietary factors have been implicated in the pathogenesis and management of IBS symptoms. This systematic review aims to evaluate the effects of polyphenols, minerals, fibers, and fruits on the symptoms and overall well-being of individuals with IBS.
MATERIALS AND METHODS
A comprehensive literature search was conducted in several electronic databases, including PubMed, Scopus, and Web of Science. Studies published up until July 2023 were included.
RESULTS
The selected studies varied in terms of study design, participant characteristics, intervention duration, and outcome measures. Overall, the findings suggest that dietary interventions involving polyphenols, minerals, fibers, and fruits can have a positive impact on IBS symptoms. Dietary fiber supplementation, particularly soluble fiber, has been associated with reduced bloating and enhanced stool consistency.
CONCLUSIONS
This systematic review provides evidence supporting the beneficial effects of polyphenols, minerals, fibers, and fruits in IBS patients. These dietary components hold promise as complementary approaches for managing IBS symptoms. However, due to the heterogeneity of the included studies and the limited number of high-quality randomized controlled trials, further well-designed trials are warranted to establish the optimal dosages, duration, and long-term effects of these interventions. Understanding the role of specific dietary components in IBS management may pave the way for personalized dietary recommendations and improve the quality of life for individuals suffering from this complex disorder.
Topics: Humans; Fruit; Polyphenols; Irritable Bowel Syndrome; Quality of Life; Minerals; Flatulence
PubMed: 37764853
DOI: 10.3390/nu15184070 -
Nutrients Sep 2023Periodontitis is a chronic multifactorial inflammatory disease, that leads to tooth loss and is associated with other systemic diseases. The role of dietary fibre in the... (Review)
Review
BACKGROUND
Periodontitis is a chronic multifactorial inflammatory disease, that leads to tooth loss and is associated with other systemic diseases. The role of dietary fibre in the prevention and management of periodontal diseases is not well understood. The objective of this systematic review and meta-analysis was to assess how an intake of dietary fibre affects periodontal diseases in humans and any concomitant effects on systemic inflammation.
METHODOLOGY
Human interventional studies investigating the effects of oral fibre intake on various clinical parameters of periodontal diseases were included. Search strategy with MeSH and free-text search terms was performed on the following database: CINAHL Complete, EMBASE, MEDLINE, SciVerse Scopus, and Web of Science Core Collection on 21 October 2021 and updated on 19 February 2023 to identify relevant studies. Articles were filtered using the Covidence© web-based platform software. Data were pooled using random effects meta-analysis.
RESULTS
From all databases, a total of 19,971 studies were obtained. Upon title and abstract screening, 101 studies were included for full-text screening. Upon full-text screening, six studies were included for analysis. Of these, five were randomised controlled trials, and one was a sequential feeding trial involving fibre-rich daily diet for a 4-8 weeks period. Fibre-rich dietary intervention significantly reduced Clinical Attachment Loss/Level by 0.48 mm/tooth (95% CI, -0.63 to -0.33, < 0.001), Bleeding On Probing by 27.57% sites/tooth (95% CI -50.40 to -4.74, = 0.02), Periodontal Inflamed Surface Area by 173.88 mm (95% CI -288.06 to -59.69, = 0.003), Plaque Index by 0.02 (95% CI -0.04 to -0.00, = 0.04), and Gingival Index by 0.41 (95% -0.67 to -0.16, = 0.002). A non-significant reduction was observed for Probing Depth (-0.17 mm/tooth; 95% CI, -0.37 to 0.02, = 0.09).
CONCLUSIONS
Fibre-rich dietary interventions are associated with a reduction of clinical and particularly inflammatory markers of periodontal diseases. This shows a promising effect of dietary fibre as an intervention for inflammatory conditions like periodontal diseases.
PubMed: 37764817
DOI: 10.3390/nu15184034