-
The American Journal of Clinical... Jun 2018Dysfunction of the gut microbiota is frequently reported as a manifestation of chronic diseases, and therefore presents as a modifiable risk factor in their development.... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Dysfunction of the gut microbiota is frequently reported as a manifestation of chronic diseases, and therefore presents as a modifiable risk factor in their development. Diet is a major regulator of the gut microbiota, and certain types of dietary fiber may modify bacterial numbers and metabolism, including short-chain fatty acid (SCFA) generation.
OBJECTIVE
A systematic review and meta-analysis were undertaken to assess the effect of dietary fiber interventions on gut microbiota composition in healthy adults.
DESIGN
A systematic search was conducted across MEDLINE, EMBASE, CENTRAL, and CINAHL for randomized controlled trials using culture and/or molecular microbiological techniques evaluating the effect of fiber intervention on gut microbiota composition in healthy adults. Meta-analyses via a random-effects model were performed on alpha diversity, prespecified bacterial abundances including Bifidobacterium and Lactobacillus spp., and fecal SCFA concentrations comparing dietary fiber interventions with placebo/low-fiber comparators.
RESULTS
A total of 64 studies involving 2099 participants were included. Dietary fiber intervention resulted in higher abundance of Bifidobacterium spp. (standardized mean difference (SMD): 0.64; 95% CI: 0.42, 0.86; P < 0.00001) and Lactobacillus spp. (SMD: 0.22; 0.03, 0.41; P = 0.02) as well as fecal butyrate concentration (SMD: 0.24; 0.00, 0.47; P = 0.05) compared with placebo/low-fiber comparators. Subgroup analysis revealed that fructans and galacto-oligosaccharides led to significantly greater abundance of both Bifidobacterium spp. and Lactobacillus spp. compared with comparators (P < 0.00001 and P = 0.002, respectively). No differences in effect were found between fiber intervention and comparators for α-diversity, abundances of other prespecified bacteria, or other SCFA concentrations.
CONCLUSIONS
Dietary fiber intervention, particularly involving fructans and galacto-oligosaccharides, leads to higher fecal abundance of Bifidobacterium and Lactobacillus spp. but does not affect α-diversity. Further research is required to better understand the role of individual fiber types on the growth of microbes and the overall gut microbial community. This review was registered at PROSPERO as CRD42016053101.
Topics: Adult; Bacteria; Dietary Fiber; Food Analysis; Gastrointestinal Microbiome; Humans
PubMed: 29757343
DOI: 10.1093/ajcn/nqy041 -
Nutrients Jun 2019While dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial.... (Meta-Analysis)
Meta-Analysis
While dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial. Dietary glycemic index (GI) and glycemic load (GL) have been examined in relation to the risk of T2D in multiple prospective cohort studies. Previous meta-analyses indicate significant relations but consideration of causality has been minimal. Here, the results of our recent meta-analyses of prospective cohort studies of 4 to 26-y follow-up are interpreted in the context of the nine Bradford-Hill criteria for causality, that is: (1) Strength of Association, (2) Consistency, (3) Specificity, (4) Temporality, (5) Biological Gradient, (6) Plausibility, (7) Experimental evidence, (8) Analogy, and (9) Coherence. These criteria necessitated referral to a body of literature wider than prospective cohort studies alone, especially in criteria 6 to 9. In this analysis, all nine of the Hill's criteria were met for GI and GL indicating that we can be confident of a role for GI and GL as causal factors contributing to incident T2D. In addition, neither dietary fiber nor cereal fiber nor wholegrain were found to be reliable or effective surrogate measures of GI or GL. Finally, our cost-benefit analysis suggests food and nutrition advice favors lower GI or GL and would produce significant potential cost savings in national healthcare budgets. The high confidence in causal associations for incident T2D is sufficient to consider inclusion of GI and GL in food and nutrient-based recommendations.
Topics: Animals; Biomarkers; Blood Glucose; Diabetes Mellitus, Type 2; Diet; Glycemic Index; Glycemic Load; Humans; Incidence; Prognosis; Risk Assessment; Risk Factors
PubMed: 31242690
DOI: 10.3390/nu11061436 -
The Journal of Pediatrics Jan 2022To evaluate the effectiveness and safety of nonpharmacologic interventions for the treatment of childhood functional constipation. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To evaluate the effectiveness and safety of nonpharmacologic interventions for the treatment of childhood functional constipation.
STUDY DESIGN
Randomized controlled trials (RCTs) evaluating nonpharmacologic treatments in children with functional constipation which reported at least 1 outcome of the core outcome set for children with functional constipation.
RESULTS
We included 52 RCTs with 4668 children, aged between 2 weeks and 18 years, of whom 47% were females. Studied interventions included gut microbiome-directed interventions, other dietary interventions, oral supplements, pelvic floor-directed interventions, electrical stimulation, dry cupping, and massage therapy. An overall high risk of bias was found across the majority of studies. Meta-analyses for treatment success and/or defecation frequency, including 20 RCTs, showed abdominal electrical stimulation (n = 3), Cassia Fistula emulsion (n = 2), and a cow's milk exclusion diet (n = 2 in a subpopulation with constipation as a possible manifestation of cow's milk allergy) may be effective. Evidence from RCTs not included in the meta-analyses, indicated that some prebiotic and fiber mixtures, Chinese herbal medicine (Xiao'er Biantong granules), and abdominal massage are promising therapies. In contrast, studies showed no benefit for the use of probiotics, synbiotics, an increase in water intake, dry cupping, or additional biofeedback or behavioral therapy. We found no RCTs on physical movement or acupuncture.
CONCLUSIONS
More well-designed high quality RCTs concerning nonpharmacologic treatments for children with functional constipation are needed before changes in current guidelines are indicated.
Topics: Biofeedback, Psychology; Cognitive Behavioral Therapy; Constipation; Cryotherapy; Diet; Electric Stimulation Therapy; Exercise Therapy; Humans; Laxatives; Massage; Phytotherapy; Prebiotics
PubMed: 34536492
DOI: 10.1016/j.jpeds.2021.09.010 -
Nutrients Sep 2021Excessive consumption of ultra-processed foods (UPFs), as described by the NOVA classification system, represents a potential threat to human health. The nutritional... (Meta-Analysis)
Meta-Analysis
Excessive consumption of ultra-processed foods (UPFs), as described by the NOVA classification system, represents a potential threat to human health. The nutritional composition of UPFs may explain their observed adverse effects. The present study aimed to provide a quantitative meta-analysis of nationally representative surveys on the consumption of UPFs and the dietary/nutrient composition of respondents' diets. A systematic search for relevant studies published prior to July 2021 was conducted via electronic databases. The studies that provided the dietary/nutrient composition of foods categorized according to the NOVA classification system were selected. The association between UPFs and other dietary variables was modelled using ordinary least squares linear regression based on aggregated data extracted from the selected articles. Consumption of UPFs represented up to 80% of total caloric intake in the US and Canada, with confectionery and sugar-sweetened beverages being the most consumed items. When considered in relation to other food groups, an inverse linear relation between UPFs and less-processed foods was evident. Increased UPF intake correlated with an increase in free sugars, total fats, and saturated fats, as well as a decrease in fiber, protein, potassium, zinc, and magnesium, and vitamins A, C, D, E, B12, and niacin. In conclusion, the data indicate that increased UPF consumption negatively affects the nutritional quality of diets.
Topics: Adolescent; Adult; Child; Diet; Dietary Sugars; Energy Intake; Fast Foods; Female; Food Handling; Food Quality; Humans; Male; Nutrition Surveys; Nutritive Value; Snacks; Sugar-Sweetened Beverages
PubMed: 34684391
DOI: 10.3390/nu13103390 -
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 -
PLoS Medicine Jul 2016Effects of major dietary macronutrients on glucose-insulin homeostasis remain controversial and may vary by the clinical measures examined. We aimed to assess how... (Meta-Analysis)
Meta-Analysis Review
Effects of Saturated Fat, Polyunsaturated Fat, Monounsaturated Fat, and Carbohydrate on Glucose-Insulin Homeostasis: A Systematic Review and Meta-analysis of Randomised Controlled Feeding Trials.
BACKGROUND
Effects of major dietary macronutrients on glucose-insulin homeostasis remain controversial and may vary by the clinical measures examined. We aimed to assess how saturated fat (SFA), monounsaturated fat (MUFA), polyunsaturated fat (PUFA), and carbohydrate affect key metrics of glucose-insulin homeostasis.
METHODS AND FINDINGS
We systematically searched multiple databases (PubMed, EMBASE, OVID, BIOSIS, Web-of-Knowledge, CAB, CINAHL, Cochrane Library, SIGLE, Faculty1000) for randomised controlled feeding trials published by 26 Nov 2015 that tested effects of macronutrient intake on blood glucose, insulin, HbA1c, insulin sensitivity, and insulin secretion in adults aged ≥18 years. We excluded trials with non-isocaloric comparisons and trials providing dietary advice or supplements rather than meals. Studies were reviewed and data extracted independently in duplicate. Among 6,124 abstracts, 102 trials, including 239 diet arms and 4,220 adults, met eligibility requirements. Using multiple-treatment meta-regression, we estimated dose-response effects of isocaloric replacements between SFA, MUFA, PUFA, and carbohydrate, adjusted for protein, trans fat, and dietary fibre. Replacing 5% energy from carbohydrate with SFA had no significant effect on fasting glucose (+0.02 mmol/L, 95% CI = -0.01, +0.04; n trials = 99), but lowered fasting insulin (-1.1 pmol/L; -1.7, -0.5; n = 90). Replacing carbohydrate with MUFA lowered HbA1c (-0.09%; -0.12, -0.05; n = 23), 2 h post-challenge insulin (-20.3 pmol/L; -32.2, -8.4; n = 11), and homeostasis model assessment for insulin resistance (HOMA-IR) (-2.4%; -4.6, -0.3; n = 30). Replacing carbohydrate with PUFA significantly lowered HbA1c (-0.11%; -0.17, -0.05) and fasting insulin (-1.6 pmol/L; -2.8, -0.4). Replacing SFA with PUFA significantly lowered glucose, HbA1c, C-peptide, and HOMA. Based on gold-standard acute insulin response in ten trials, PUFA significantly improved insulin secretion capacity (+0.5 pmol/L/min; 0.2, 0.8) whether replacing carbohydrate, SFA, or even MUFA. No significant effects of any macronutrient replacements were observed for 2 h post-challenge glucose or insulin sensitivity (minimal-model index). Limitations included a small number of trials for some outcomes and potential issues of blinding, compliance, generalisability, heterogeneity due to unmeasured factors, and publication bias.
CONCLUSIONS
This meta-analysis of randomised controlled feeding trials provides evidence that dietary macronutrients have diverse effects on glucose-insulin homeostasis. In comparison to carbohydrate, SFA, or MUFA, most consistent favourable effects were seen with PUFA, which was linked to improved glycaemia, insulin resistance, and insulin secretion capacity.
Topics: Adult; Blood Glucose; Dietary Carbohydrates; Fats, Unsaturated; Fatty Acids, Monounsaturated; Fatty Acids, Unsaturated; Glycated Hemoglobin; Homeostasis; Humans; Insulin; Randomized Controlled Trials as Topic
PubMed: 27434027
DOI: 10.1371/journal.pmed.1002087 -
Nutrients Aug 2020Although a cholesterol-lowering diet and the addition of plant sterols and stanols are suggested for the lipid management of children and adults with familial... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Although a cholesterol-lowering diet and the addition of plant sterols and stanols are suggested for the lipid management of children and adults with familial hypercholesterolemia, there is limited evidence evaluating such interventions in this population.
OBJECTIVES
To investigate the impact of cholesterol-lowering diet and other dietary interventions on the incidence or mortality of cardiovascular disease and lipid profile of patients with familial hypercholesterolemia.
SEARCH METHODS
Relevant trials were identified by searching US National Library of Medicine National Institutes of Health Metabolism Trials Register and clinicaltrials.gov.gr using the following terms: diet, dietary, plant sterols, stanols, omega-3 fatty acids, fiber and familial hypercholesterolemia.
SELECTION CRITERIA
Randomized controlled trials evaluating the effect of cholesterol-lowering diet or other dietary interventions in children and adults with familial hypercholesterolemia were included.
DATA COLLECTION AND ANALYSIS
Two authors independently assessed the eligibility of the included trials and their bias risk and extracted the data which was independently verified by other colleagues.
RESULTS
A total of 17 trials were finally included, with a total of 376 participants across 8 comparison groups. The included trials had either a low or unclear bias risk for most of the assessed risk parameters. Cardiovascular incidence or mortality were not evaluated in any of the included trials. Among the planned comparisons regarding patients' lipidemic profile, a significant difference was noticed for the following comparisons and outcomes: omega-3 fatty acids reduced triglycerides (mean difference (MD): -0.27 mmol/L, 95% confidence interval (CI): -0.47 to -0.07, < 0.01) when compared with placebo. A non-significant trend towards a reduction in subjects' total cholesterol (MD: -0.34, 95% CI: -0.68 to 0, mmol/L, = 0.05) and low-density lipoprotein cholesterol (MD: -0.31, 95% CI: -0.61 to 0, mmol/L, = 0.05) was noticed. In comparison with cholesterol-lowering diet, the additional consumption of plant stanols decreased total cholesterol (MD: -0.62 mmol/L, 95% CI: -1.13 to -0.11, = 0.02) and low-density lipoprotein cholesterol (MD: -0.58 mmol/L, 95% CI: -1.08 to -0.09, = 0.02). The same was by plant sterols (MD: -0.46 mmol/L, 95% CI: -0.76 to -0.17, < 0.01 for cholesterol and MD: -0.45 mmol/L, 95% CI: -0.74 to -0.16, < 0.01 for low-density lipoprotein cholesterol). No heterogeneity was noticed among the studies included in these analyses.
CONCLUSIONS
Available trials confirm that the addition of plant sterols or stanols has a cholesterol-lowering effect on such individuals. On the other hand, supplementation with omega-3 fatty acids effectively reduces triglycerides and might have a role in lowering the cholesterol of patients with familial hypercholesterolemia. Additional studies are needed to investigate the efficacy of cholesterol-lowering diet or the addition of soya protein and dietary fibers to a cholesterol-lowering diet in patients with familial hypercholesterolemia.
Topics: Adult; Anticholesteremic Agents; Cardiovascular Diseases; Child; Cholesterol; Cholesterol, LDL; Clinical Trials as Topic; Diet; Dietary Supplements; Fatty Acids, Omega-3; Female; Heart Disease Risk Factors; Humans; Hyperlipoproteinemia Type II; Male; Phytosterols; Triglycerides
PubMed: 32823643
DOI: 10.3390/nu12082436 -
Alimentary Pharmacology & Therapeutics Nov 2018Irritable bowel syndrome (IBS) is a chronic functional bowel disorder. Disturbances in the gastrointestinal microbiome may be involved in its aetiology. (Meta-Analysis)
Meta-Analysis
BACKGROUND
Irritable bowel syndrome (IBS) is a chronic functional bowel disorder. Disturbances in the gastrointestinal microbiome may be involved in its aetiology.
AIM
To perform a systematic review and meta-analysis to examine the efficacy of prebiotics, probiotics, synbiotics and antibiotics in IBS.
METHODS
MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched (up to July 2017). Randomised controlled trials (RCTs) recruiting adults with IBS, comparing prebiotics, probiotics, synbiotics or antibiotics 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 standardised mean difference with a 95% CI.
RESULTS
The search identified 4017 citations. Data for prebiotics and synbiotics were sparse. Fifty-three RCTs of probiotics, involving 5545 patients, were eligible. Particular combinations of probiotics, or specific species and strains, appeared to have beneficial effects on global IBS symptoms and abdominal pain, but it was not possible to draw definitive conclusions about their efficacy. There were five trials of similar design that used rifaximin in non-constipated IBS patients, which was more effective than placebo (RR of symptoms persisting = 0.84; 95% CI 0.79-0.90). Adverse events were no more common with probiotics or antibiotics.
CONCLUSIONS
Which particular combination, species or strains of probiotics are effective for IBS remains, for the most part, unclear. Rifaximin has modest efficacy in improving symptoms in non-constipated IBS.
Topics: Abdominal Pain; Adult; Anti-Bacterial Agents; Gastrointestinal Agents; Gastrointestinal Microbiome; Humans; Irritable Bowel Syndrome; Prebiotics; Probiotics; Randomized Controlled Trials as Topic; Rifaximin; Synbiotics; Treatment Outcome
PubMed: 30294792
DOI: 10.1111/apt.15001 -
Nutrients Jul 2021Probiotic and prebiotic products have shown potential health benefits, including for the prevention of adverse pregnancy outcomes. The incidence of adverse effects in... (Meta-Analysis)
Meta-Analysis
Probiotic and prebiotic products have shown potential health benefits, including for the prevention of adverse pregnancy outcomes. The incidence of adverse effects in pregnant people and their infants associated with probiotic/prebiotic/synbiotic intake, however, remains unclear. The objectives of this study were to evaluate the evidence on adverse effects of maternal probiotic, prebiotic, and/or synbiotic supplementation during pregnancy and lactation and interpret the findings to help inform clinical decision-making and care of this population. A systematic review was conducted following PRISMA guidelines. Scientific databases were searched using pre-determined terms, and risk of bias assessments were conducted to determine study quality. Inclusion criteria were English language studies, human studies, access to full-text, and probiotic/prebiotic/synbiotic supplementation to the mother and not the infant. In total, 11/100 eligible studies reported adverse effects and were eligible for inclusion in quantitative analysis, and data were visualised in a GOfER diagram. Probiotic and prebiotic products are safe for use during pregnancy and lactation. One study reported increased risk of vaginal discharge and changes in stool consistency (relative risk [95% CI]: 3.67 [1.04, 13.0]) when administering and Adverse effects associated with probiotic and prebiotic use do not pose any serious health concerns to mother or infant. Our findings and knowledge translation visualisations provide healthcare professionals and consumers with information to make evidence-informed decisions about the use of pre- and probiotics.
Topics: Female; Humans; Infant; Infant, Newborn; Lactation; Prebiotics; Pregnancy; Prenatal Exposure Delayed Effects; Probiotics; Risk Assessment; Risk Factors; Synbiotics
PubMed: 34371892
DOI: 10.3390/nu13072382 -
Role of Dietary Habits in the Prevention of Diverticular Disease Complications: A Systematic Review.Nutrients Apr 2021Recent evidence showed that dietary habits play a role as risk factors for the development of diverticular complications. This systematic review aims to assess the...
Recent evidence showed that dietary habits play a role as risk factors for the development of diverticular complications. This systematic review aims to assess the effect of dietary habits in the prevention of diverticula complications (i.e., acute diverticulitis and diverticula bleeding) in patients with diverticula disease. PubMed and Scopus databases were searched up to 19 January 2021, 330 records were identified, and 8 articles met the eligibility criteria and were subjected to data extraction. The quality of the studies was evaluated by the Newcastle-Ottawa quality assessment form. No study meets the criteria for being a high-quality study. A high intake of fiber was associated to a decreased risk of diverticulitis or hospitalization due to diverticular disease, with a protective effect for fruits and cereal fiber, but not for vegetable fiber; whereas, a high red meat consumption and a generally Western dietary pattern were associated with an increased risk of diverticulitis. Alcohol use seemed to be associated to diverticular bleeding, but not to recurrent diverticulitis or diverticular complications. Further high-quality studies are needed to better define these associations. It is mandatory to ascertain the role of dietary habits for the development of recurrent acute diverticulitis and diverticular bleeding.
Topics: Diet, Western; Dietary Fiber; Diverticulitis; Diverticulosis, Colonic; Edible Grain; Feeding Behavior; Fruit; Gastrointestinal Hemorrhage; Hospitalization; Humans; Meat; Recurrence; Vegetables
PubMed: 33919755
DOI: 10.3390/nu13041288