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Gut Jun 2022A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) is recommended for irritable bowel syndrome (IBS), if general lifestyle... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) is recommended for irritable bowel syndrome (IBS), if general lifestyle and dietary advice fails. However, although the impact of a low FODMAP diet on individual IBS symptoms has been examined in some randomised controlled trials (RCTs), there has been no recent systematic assessment, and individual trials have studied numerous alternative or control interventions, meaning the best comparator is unclear. We performed a network meta-analysis addressing these uncertainties.
DESIGN
We searched the medical literature through to 2 April 2021 to identify RCTs of a low FODMAP diet in IBS. Efficacy was judged using dichotomous assessment of improvement in global IBS symptoms or improvement in individual IBS symptoms, including abdominal pain, abdominal bloating or distension, and bowel habit. Data were pooled using a random effects model, with efficacy reported as pooled relative risks (RRs) with 95% CIs, and interventions ranked according to their P-score.
RESULTS
We identified 13 eligible RCTs (944 patients). Based on failure to achieve an improvement in global IBS symptoms, a low FODMAP diet ranked first vs habitual diet (RR of symptoms not improving=0.67; 95% CI 0.48 to 0.91, P-score=0.99), and was superior to all other interventions. Low FODMAP diet ranked first for abdominal pain severity, abdominal bloating or distension severity and bowel habit, although for the latter it was not superior to any other intervention. A low FODMAP diet was superior to British Dietetic Association (BDA)/National Institute for Health and Care Excellence (NICE) dietary advice for abdominal bloating or distension (RR=0.72; 95% CI 0.55 to 0.94). BDA/NICE dietary advice was not superior to any other intervention in any analysis.
CONCLUSION
In a network analysis, low FODMAP diet ranked first for all endpoints studied. However, most trials were based in secondary or tertiary care and did not study effects of FODMAP reintroduction and personalisation on symptoms.
Topics: Abdominal Pain; Diet, Carbohydrate-Restricted; Disaccharides; Humans; Irritable Bowel Syndrome; Monosaccharides; Network Meta-Analysis; Oligosaccharides
PubMed: 34376515
DOI: 10.1136/gutjnl-2021-325214 -
Advances in Nutrition (Bethesda, Md.) Sep 2020The Dietary Approaches to Stop Hypertension (DASH) diet is recognized as an effective dietary intervention to reduce blood pressure (BP). However, among randomized... (Meta-Analysis)
Meta-Analysis
Dietary Approaches to Stop Hypertension (DASH) Diet and Blood Pressure Reduction in Adults with and without Hypertension: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
The Dietary Approaches to Stop Hypertension (DASH) diet is recognized as an effective dietary intervention to reduce blood pressure (BP). However, among randomized controlled trials (RCTs) investigating the DASH diet-mediated BP reduction, there are significant methodological and clinical differences. The purpose of this study was to comprehensively assess the DASH diet effect on BP in adults with and without hypertension, accounting for underlying methodological and clinical confounders. We systematically searched Medline and the Cochrane Collaboration Library databases and identified 30 RCTs (n = 5545 participants) that investigated the BP effects of the DASH diet compared with a control diet in hypertensive and nonhypertensive adults. Both random-effects and fixed-effect models were used to calculate the mean attained systolic BP (SBP) and diastolic BP (DBP) differences during follow-up. Subgroup and meta-regression analyses were also conducted. Compared with a control diet, the DASH diet reduced both SBP and DBP (difference in means: -3.2 mm Hg; 95% CI: -4.2, -2.3 mm Hg; P < 0.001, and -2.5 mm Hg; 95% CI: -3.5, -1.5 mm Hg; P < 0.001, respectively). Hypertension status did not modify the effect on BP reduction. The DASH diet compared with a control diet reduced SBP levels to a higher extent in trials with sodium intake >2400 mg/d than in trials with sodium intake ≤2400 mg/d, whereas both SBP and DBP were reduced more in trials with mean age <50 y than in trials of older participants. The quality of evidence was rated as moderate for both outcomes according to the Grading of Recommendations, Assessment, Development, and Evaluation approach. The adoption of the DASH diet was accompanied by significant BP reduction in adults with and without hypertension, although higher daily sodium intake and younger age enhanced the BP-lowering effect of the intervention. This meta-analysis was registered at www.crd.york.ac.uk/prospero as CRD42019128120.
Topics: Adult; Blood Pressure; Diet, Sodium-Restricted; Dietary Approaches To Stop Hypertension; Humans; Hypertension; Randomized Controlled Trials as Topic
PubMed: 32330233
DOI: 10.1093/advances/nmaa041 -
International Journal of Environmental... Aug 2022A ketogenic diet, characterized by low calories with high levels of fat, adequate levels of protein, and low levels of carbohydrates, has beneficial effects on body... (Meta-Analysis)
Meta-Analysis Review
Ketogenic Diet Benefits to Weight Loss, Glycemic Control, and Lipid Profiles in Overweight Patients with Type 2 Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trails.
A ketogenic diet, characterized by low calories with high levels of fat, adequate levels of protein, and low levels of carbohydrates, has beneficial effects on body weight control in overweight patients. In the present study, a meta-analysis was conducted to investigate the role of a ketogenic diet in body weight control and glycemic management in overweight patients with type 2 diabetes mellitus (T2DM). In summary, we systematically reviewed articles from the Embase, PubMed, Web of Science and Cochrane Library databases and obtained eight randomized controlled trials for meta-analysis. The results show that a ketogenic diet had significantly beneficial effects on the loss of body weight (SMD, -5.63, = 0.008), the reduction of waist circumference (SMD, -2.32, = 0.04), lowering glycated hemoglobin (SMD, -0.38, = 0.0008) and triglycerides (SMD, -0.36, = 0.0001), and increasing high-density lipoproteins (SMD, 0.28, = 0.003). Overall, these results suggest that a ketogenic diet may be an effective dietary intervention for body weight and glycemic control, as well as improved lipid profiles in overweight patients with T2DM. Hence, a ketogenic diet can be recommended for the therapeutic intervention of overweight patients with T2DM.
Topics: Blood Glucose; Body Weight; Diabetes Mellitus, Type 2; Diet, Ketogenic; Glycemic Control; Humans; Overweight; Triglycerides; Weight Loss
PubMed: 36012064
DOI: 10.3390/ijerph191610429 -
BMJ (Clinical Research Ed.) Apr 2020To determine the relative effectiveness of dietary macronutrient patterns and popular named diet programmes for weight loss and cardiovascular risk factor improvement... (Meta-Analysis)
Meta-Analysis
Comparison of dietary macronutrient patterns of 14 popular named dietary programmes for weight and cardiovascular risk factor reduction in adults: systematic review and network meta-analysis of randomised trials.
OBJECTIVE
To determine the relative effectiveness of dietary macronutrient patterns and popular named diet programmes for weight loss and cardiovascular risk factor improvement among adults who are overweight or obese.
DESIGN
Systematic review and network meta-analysis of randomised trials.
DATA SOURCES
Medline, Embase, CINAHL, AMED, and CENTRAL from database inception until September 2018, reference lists of eligible trials, and related reviews.
STUDY SELECTION
Randomised trials that enrolled adults (≥18 years) who were overweight (body mass index 25-29) or obese (≥30) to a popular named diet or an alternative diet.
OUTCOMES AND MEASURES
Change in body weight, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, systolic blood pressure, diastolic blood pressure, and C reactive protein at the six and 12 month follow-up.
REVIEW METHODS
Two reviewers independently extracted data on study participants, interventions, and outcomes and assessed risk of bias, and the certainty of evidence using the GRADE (grading of recommendations, assessment, development, and evaluation) approach. A bayesian framework informed a series of random effects network meta-analyses to estimate the relative effectiveness of the diets.
RESULTS
121 eligible trials with 21 942 patients were included and reported on 14 named diets and three control diets. Compared with usual diet, low carbohydrate and low fat diets had a similar effect at six months on weight loss (4.63 4.37 kg, both moderate certainty) and reduction in systolic blood pressure (5.14 mm Hg, moderate certainty 5.05 mm Hg, low certainty) and diastolic blood pressure (3.21 2.85 mm Hg, both low certainty). Moderate macronutrient diets resulted in slightly less weight loss and blood pressure reductions. Low carbohydrate diets had less effect than low fat diets and moderate macronutrient diets on reduction in LDL cholesterol (1.01 mg/dL, low certainty 7.08 mg/dL, moderate certainty 5.22 mg/dL, moderate certainty, respectively) but an increase in HDL cholesterol (2.31 mg/dL, low certainty), whereas low fat (-1.88 mg/dL, moderate certainty) and moderate macronutrient (-0.89 mg/dL, moderate certainty) did not. Among popular named diets, those with the largest effect on weight reduction and blood pressure in comparison with usual diet were Atkins (weight 5.5 kg, systolic blood pressure 5.1 mm Hg, diastolic blood pressure 3.3 mm Hg), DASH (3.6 kg, 4.7 mm Hg, 2.9 mm Hg, respectively), and Zone (4.1 kg, 3.5 mm Hg, 2.3 mm Hg, respectively) at six months (all moderate certainty). No diets significantly improved levels of HDL cholesterol or C reactive protein at six months. Overall, weight loss diminished at 12 months among all macronutrient patterns and popular named diets, while the benefits for cardiovascular risk factors of all interventions, except the Mediterranean diet, essentially disappeared.
CONCLUSIONS
Moderate certainty evidence shows that most macronutrient diets, over six months, result in modest weight loss and substantial improvements in cardiovascular risk factors, particularly blood pressure. At 12 months the effects on weight reduction and improvements in cardiovascular risk factors largely disappear.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO CRD42015027929.
Topics: Blood Pressure; Body Mass Index; Body Weight; Cardiovascular Diseases; Cholesterol, HDL; Cholesterol, LDL; Diet, Carbohydrate-Restricted; Diet, Fat-Restricted; Diet, Mediterranean; Humans; Network Meta-Analysis; Nutrients; Obesity; Randomized Controlled Trials as Topic; Risk Reduction Behavior; Weight Loss
PubMed: 32238384
DOI: 10.1136/bmj.m696 -
Critical Reviews in Food Science and... Nov 2017Beneficial effects of vegetarian and vegan diets on health outcomes have been supposed in previous studies. (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Beneficial effects of vegetarian and vegan diets on health outcomes have been supposed in previous studies.
OBJECTIVES
Aim of this study was to clarify the association between vegetarian, vegan diets, risk factors for chronic diseases, risk of all-cause mortality, incidence, and mortality from cardio-cerebrovascular diseases, total cancer and specific type of cancer (colorectal, breast, prostate and lung), through meta-analysis.
METHODS
A comprehensive search of Medline, EMBASE, Scopus, The Cochrane Library, and Google Scholar was conducted.
RESULTS
Eighty-six cross-sectional and 10 cohort prospective studies were included. The overall analysis among cross-sectional studies reported significant reduced levels of body mass index, total cholesterol, LDL-cholesterol, and glucose levels in vegetarians and vegans versus omnivores. With regard to prospective cohort studies, the analysis showed a significant reduced risk of incidence and/or mortality from ischemic heart disease (RR 0.75; 95% CI, 0.68 to 0.82) and incidence of total cancer (RR 0.92; 95% CI 0.87 to 0.98) but not of total cardiovascular and cerebrovascular diseases, all-cause mortality and mortality from cancer. No significant association was evidenced when specific types of cancer were analyzed. The analysis conducted among vegans reported significant association with the risk of incidence from total cancer (RR 0.85; 95% CI, 0.75 to 0.95), despite obtained only in a limited number of studies.
CONCLUSIONS
This comprehensive meta-analysis reports a significant protective effect of a vegetarian diet versus the incidence and/or mortality from ischemic heart disease (-25%) and incidence from total cancer (-8%). Vegan diet conferred a significant reduced risk (-15%) of incidence from total cancer.
Topics: Cardiovascular Diseases; Cross-Sectional Studies; Diet, Vegan; Diet, Vegetarian; Health Status; Humans; Neoplasms; Prospective Studies; Vegetarians
PubMed: 26853923
DOI: 10.1080/10408398.2016.1138447 -
Headache Jul 2020Migraine is a disabling primary headache disorder often associated with triggers. Diet-related triggers are a common cause of migraine and certain diets have been...
BACKGROUND
Migraine is a disabling primary headache disorder often associated with triggers. Diet-related triggers are a common cause of migraine and certain diets have been reported to decrease the frequency of migraine attacks if dietary triggers or patterns are adjusted.
OBJECTIVE
The systematic literature review was conducted to qualitatively summarize evidence from the published literature regarding the role of diet patterns, diet-related triggers, and diet interventions in people with migraine.
METHODS
A literature search was carried out on diet patterns, diet-related triggers, and diet interventions used to treat and/or prevent migraine attacks, using an a priori protocol. MEDLINE and EMBASE databases were searched to identify studies assessing the effect of diet, food, and nutrition in people with migraine aged ≥18 years. Only primary literature sources (randomized controlled trials or observational studies) were included and searches were conducted from January 2000 to March 2019. The NICE checklist was used to assess the quality of the included studies of randomized controlled trials and the Downs and Black checklist was used for the assessment of observational studies.
RESULTS
A total of 43 studies were included in this review, of which 11 assessed diet patterns, 12 assessed diet interventions, and 20 assessed diet-related triggers. The overall quality of evidence was low, as most of the (68%) studies assessing diet patterns and diet-related triggers were cross-sectional studies or patient surveys. The studies regarding diet interventions assessed a variety of diets, such as ketogenic diet, elimination diets, and low-fat diets. Alcohol and caffeine uses were the most common diet patterns and diet-related triggers associated with increased frequency of migraine attacks. Most of the diet interventions, such as low-fat and elimination diets, were related to a decrease in the frequency of migraine attacks.
CONCLUSIONS
There is limited high-quality randomized controlled trial data on diet patterns or diet-related triggers. A few small randomized controlled trials have assessed diet interventions in preventing migraine attacks without strong results. Although many patients already reported avoiding personal diet-related triggers in their migraine management, high-quality research is needed to confirm the effect of diet in people with migraine.
Topics: Diet; Diet Therapy; Feeding Behavior; Humans; Migraine Disorders; Precipitating Factors
PubMed: 32449944
DOI: 10.1111/head.13836 -
European Journal of Clinical Nutrition Sep 2022Ketogenic diet therapy (KDT) is an established nonpharmacologic treatment in various types of epilepsy. We aim to evaluate the quality of the systematic reviews and... (Meta-Analysis)
Meta-Analysis Review
Ketogenic diet therapy (KDT) is an established nonpharmacologic treatment in various types of epilepsy. We aim to evaluate the quality of the systematic reviews and meta-analyses (SRMAs) of KDT for epilepsy and summarize the evidence on their effects. We conducted an overview on MEDLINE, EMBASE, Cochrane Database of Systematic Review, and Web of Science from database inception to 3 September 2020. Two investigators independently performed study selection to include SRMAs, extracted data and assessed the quality of SRMAs with the AMSTAR-2 and PRISMA statement. Twenty-four SRMAs were selected which encompassed a total of 255 original studies. Four reviews assessed the effects of KDT on infant patients; thirteen reviews reported on children and adolescent patients; eight reviews focused on adults or all patients; four assessed cognitive and behavior outcomes; three assessed quality of life; two assessed growth and development outcomes; seventeen reported on adverse effects; seven reported on retention; ten reported on attrition and reasons; and four reported on death outcomes. Overall, positive effects of KDT for epilepsy on seizure frequency reduction, as well as cognition and behavior were observed. In contrast, the effects of KDT on quality of life, growth and development were more controversial. The present overview indicates that KDT is safe. The most prevalent adverse events were GI, weight loss, and metabolic disorders, while the most common reasons for discontinuance were the lack of observed efficacy and dietary intolerance.
Topics: Adolescent; Adult; Child; Cognition; Diet, Ketogenic; Epilepsy; Humans; Infant; Quality of Life
PubMed: 35027683
DOI: 10.1038/s41430-021-01060-8 -
European Journal of Nutrition Feb 2023Vegetarian diets have been associated with reduced risk of ischemic heart disease (IHD). However, results regarding cardiovascular disease (CVD) overall and stroke are... (Meta-Analysis)
Meta-Analysis Review
PURPOSE
Vegetarian diets have been associated with reduced risk of ischemic heart disease (IHD). However, results regarding cardiovascular disease (CVD) overall and stroke are less clear. We conducted a systematic review and meta-analysis of prospective cohort studies on CVD, IHD and stroke risk among vegetarians or vegans versus nonvegetarians to clarify these associations.
METHODS
PubMed and Ovid Embase databases were searched through August 12, 2021. Prospective cohort studies reporting adjusted relative risk (RR) estimates and 95% confidence intervals (CIs) for incidence or mortality from CVD, IHD and stroke, comparing vegetarians and vegans to nonvegetarians were included. Risk of bias (RoB) was assessed using ROBINS-I and the strength of evidence was assessed using World Cancer Research Fund (WCRF) criteria. Summary RRs (95% CIs) were estimated using a random effects model.
RESULTS
Thirteen cohort studies (844,175 participants, 115,392 CVD, 30,377 IHD, and 14,419 stroke cases) were included. The summary RR for vegetarians vs. nonvegetarians was 0.85 (95% CI: 0.79-0.92, I = 68%, n = 8) for CVD, 0.79 (95% CI: 0.71-0.88, I = 67%, n = 8) for IHD, 0.90 (95% CI: 0.77-1.05, I = 61%, n = 12) for total stroke, and for vegans vs. nonvegetarians was 0.82 (95% CI: 0.68-1.00, I = 0%, n = 6) for IHD. RoB was moderate (n = 8) to serious (n = 5). The associations between vegetarian diets and CVD and IHD were considered probably causal using WCRF criteria.
CONCLUSIONS
Vegetarian diets are associated with reduced risk of CVD and IHD, but not stroke, but further studies are needed on stroke. These findings should be considered in dietary guidelines.
REVIEW REGISTRATION
No review protocol registered.
Topics: Humans; Cardiovascular Diseases; Diet, Vegan; Prospective Studies; Myocardial Ischemia; Diet, Vegetarian; Vegetarians; Cohort Studies
PubMed: 36030329
DOI: 10.1007/s00394-022-02942-8 -
Nutrients Nov 2023In recent years, the vegetarian diet has increased in popularity among athletes. The aim of this review is to ascertain the differences in variables related to... (Review)
Review
INTRODUCTION
In recent years, the vegetarian diet has increased in popularity among athletes. The aim of this review is to ascertain the differences in variables related to performance, nutritional intake, and health in athletes according to whether they are omnivores or vegetarians.
METHODOLOGY
A literature search was carried out in different databases: PubMed, Web of Science, Dialnet, and Cochrane. The keywords used were "vegetarian diet", "vegan diet", "exercise", "sport", and "performance". After applying different inclusion criteria, six studies were included in the review.
RESULTS
No significant differences were obtained in variables related to physical performance (adherence exercise, Vo2Máx, muscle power, and sprint test) or health (body composition, psychological well-being, and social relationships), but dietary intake was significantly higher in carbohydrates and lower in proteins in vegetarian athletes ( < 0.05).
CONCLUSIONS
It cannot be affirmed that vegetarian subjects have a higher sports performance, for which more research should be carried out.
Topics: Humans; Diet, Vegetarian; Vegetarians; Diet, Vegan; Exercise; Athletic Performance; Diet
PubMed: 37960356
DOI: 10.3390/nu15214703 -
BMJ Open Aug 2015To summarise the evidence about the efficacy of a Mediterranean diet on the management of type 2 diabetes and prediabetic states. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
To summarise the evidence about the efficacy of a Mediterranean diet on the management of type 2 diabetes and prediabetic states.
DESIGN
A systematic review of all meta-analyses and randomised controlled trials (RCTs) that compared the Mediterranean diet with a control diet on the treatment of type 2 diabetes and prediabetic states was conducted. Electronic searches were carried out up to January 2015. Trials were included for meta-analyses if they had a control group treated with another diet, if they were of sufficient duration (at least 6 months), and if they had at least 30 participants in each arm. A random-effect model was used to pool data.
PARTICIPANTS
Adults with or at risk for type 2 diabetes.
INTERVENTIONS
Dietary patterns that described themselves as using a 'Mediterranean' dietary pattern.
OUTCOME MEASURES
The outcomes were glycaemic control, cardiovascular risk factors and remission from the metabolic syndrome.
RESULTS
From 2824 studies, 8 meta-analyses and 5 RCTs were eligible. A 'de novo' meta-analysis of 3 long-term (>6 months) RCTs of the Mediterranean diet and glycaemic control of diabetes favoured the Mediterranean diet as compared with lower fat diets. Another 'de novo' meta-analysis of two long-term RCTs showed a 49% increased probability of remission from the metabolic syndrome. 5 meta-analyses showed a favourable effect of the Mediterranean diet, as compared with other diets, on body weight, total cholesterol and high-density lipoprotein cholesterol. 2 meta-analyses demonstrated that higher adherence to the Mediterranean diet reduced the risk of future diabetes by 19-23%.
CONCLUSIONS
The Mediterranean diet was associated with better glycaemic control and cardiovascular risk factors than control diets, including a lower fat diet, suggesting that it is suitable for the overall management of type 2 diabetes.
Topics: Adult; Blood Glucose; Cardiovascular Diseases; Cholesterol, HDL; Diabetes Mellitus, Type 2; Diet, Fat-Restricted; Diet, Mediterranean; Humans; Randomized Controlled Trials as Topic; Risk Factors; Weight Loss
PubMed: 26260349
DOI: 10.1136/bmjopen-2015-008222