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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 -
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 -
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 -
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 -
Nutrition Reviews Apr 2022It has been suggested that a gluten-free and casein-free (GFCF) diet may alleviate the symptoms of autism spectrum disorder (ASD) and facilitate neurodevelopment of... (Meta-Analysis)
Meta-Analysis
CONTEXT
It has been suggested that a gluten-free and casein-free (GFCF) diet may alleviate the symptoms of autism spectrum disorder (ASD) and facilitate neurodevelopment of children with ASD. Studies to date have been inconclusive.
OBJECTIVE
This study aimed to evaluate (through quantitative meta-analysis) the efficacy and safety of a GFCF diet for children with ASD. To our knowledge, this is the first time such an analysis has been carried out.
DATA SOURCES
Eight electronic databases were searched, from the establishment of each database up to March 27, 2020: PubMed, Web of Science, Embase (Ovid), PsycINFO (Ovid), Cochrane Library, CNKI, Wanfang, and VIP databases.
DATA EXTRACTION
Two authors independently performed the data extraction and risk-of-bias assessment.
DATA ANALYSIS
A quantitative meta-analysis was performed with standard procedures by using Stata SE 15 software. Within the total of 8 studies, with 297 participants, 5 studies reported significant reductions in stereotypical behaviors [standard mean difference (SMD) = -0.41, 95% confidence interval (CI): -0.68 to -0.15], and 3 studies reported improvements in cognition (SMD = -0.46, 95% CI: -0.91 to -0.01) following GFCF dietary intervention . No statistically significant changes were observed in other symptomatic categories (all P > 0.05).
CONCLUSION
The current meta-analysis showed that a GFCF diet can reduce stereotypical behaviors and improve the cognition of children with ASD. Though most of the included studies were single-blind, the benefits of a GFCF diet that have been indicated are promising. Additional studies on a larger scale are warranted.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO registration no. CRD42020177619.
Topics: Autism Spectrum Disorder; Caseins; Child; Diet, Gluten-Free; Humans; Single-Blind Method
PubMed: 34617108
DOI: 10.1093/nutrit/nuab073 -
Nutrients May 2018Rising rates of gestational diabetes mellitus (GDM) and related complications have prompted calls to identify potentially modifiable risk factors that are associated... (Meta-Analysis)
Meta-Analysis Review
Rising rates of gestational diabetes mellitus (GDM) and related complications have prompted calls to identify potentially modifiable risk factors that are associated with gestational diabetes mellitus (GDM). We systematically reviewed the scientific literature for observational studies examining specific dietary and/or physical activity (PA) factors and risk of GDM. Our search included PubMed, Medline, CINAHL/EBSCO, Science Direct and EMBASE, and identified 1167 articles, of which 40 met our inclusion criteria (e.g., singleton pregnancy, reported diet or PA data during pre-pregnancy/early pregnancy and GDM as an outcome measure). Studies were assessed for quality using a modified Quality Criteria Checklist from American Dietetic Association. Of the final 40 studies, 72% obtained a positive quality rating and 28% were rated neutral. The final analysis incorporated data on 30,871 pregnant women. Dietary studies were categorised into either caffeine, carbohydrate, fat, protein, calcium, fast food and recognized dietary patterns. Diets such as Mediterranean Diet (MedDiet), Dietary Approaches to Stop Hypertension (DASH) diet and Alternate Healthy Eating Index diet (AHEI) were associated with 15–38% reduced relative risk of GDM. In contrast, frequent consumption of potato, meat/processed meats, and protein (% energy) derived from animal sources was associated with an increased risk of GDM. Compared to no PA, any pre-pregnancy or early pregnancy PA was associated with 30% and 21% reduced odds of GDM, respectively. Engaging in >90 min/week of leisure time PA before pregnancy was associated with 46% decreased odds of GDM. We conclude that diets resembling MedDiet/DASH diet as well as higher PA levels before or in early pregnancy were associated with lower risks or odds of GDM respectively. The systematic review was registered at PROSPERO (www.crd.york.ac.uk/PROSPERO) as CRD42016027795.
Topics: Diabetes, Gestational; Diet, Healthy; Diet, Mediterranean; Dietary Approaches To Stop Hypertension; Evidence-Based Medicine; Exercise; Female; Healthy Lifestyle; Humans; Maternal Nutritional Physiological Phenomena; Preconception Care; Pregnancy; Prenatal Nutritional Physiological Phenomena; Protective Factors
PubMed: 29849003
DOI: 10.3390/nu10060698 -
BMJ (Clinical Research Ed.) Jan 2021To determine the efficacy and safety of low carbohydrate diets (LCDs) and very low carbohydrate diets (VLCDs) for people with type 2 diabetes. (Meta-Analysis)
Meta-Analysis
Efficacy and safety of low and very low carbohydrate diets for type 2 diabetes remission: systematic review and meta-analysis of published and unpublished randomized trial data.
OBJECTIVE
To determine the efficacy and safety of low carbohydrate diets (LCDs) and very low carbohydrate diets (VLCDs) for people with type 2 diabetes.
DESIGN
Systematic review and meta-analysis.
DATA SOURCES
Searches of CENTRAL, Medline, Embase, CINAHL, CAB, and grey literature sources from inception to 25 August 2020.
STUDY SELECTION
Randomized clinical trials evaluating LCDs (<130 g/day or <26% of a 2000 kcal/day diet) and VLCDs (<10% calories from carbohydrates) for at least 12 weeks in adults with type 2 diabetes were eligible.
DATA EXTRACTION
Primary outcomes were remission of diabetes (HbA <6.5% or fasting glucose <7.0 mmol/L, with or without the use of diabetes medication), weight loss, HbA, fasting glucose, and adverse events. Secondary outcomes included health related quality of life and biochemical laboratory data. All articles and outcomes were independently screened, extracted, and assessed for risk of bias and GRADE certainty of evidence at six and 12 month follow-up. Risk estimates and 95% confidence intervals were calculated using random effects meta-analysis. Outcomes were assessed according to a priori determined minimal important differences to determine clinical importance, and heterogeneity was investigated on the basis of risk of bias and seven a priori subgroups. Any subgroup effects with a statistically significant test of interaction were subjected to a five point credibility checklist.
RESULTS
Searches identified 14 759 citations yielding 23 trials (1357 participants), and 40.6% of outcomes were judged to be at low risk of bias. At six months, compared with control diets, LCDs achieved higher rates of diabetes remission (defined as HbA <6.5%) (76/133 (57%) 41/131 (31%); risk difference 0.32, 95% confidence interval 0.17 to 0.47; 8 studies, n=264, I=58%). Conversely, smaller, non-significant effect sizes occurred when a remission definition of HbA <6.5% without medication was used. Subgroup assessments determined as meeting credibility criteria indicated that remission with LCDs markedly decreased in studies that included patients using insulin. At 12 months, data on remission were sparse, ranging from a small effect to a trivial increased risk of diabetes. Large clinically important improvements were seen in weight loss, triglycerides, and insulin sensitivity at six months, which diminished at 12 months. On the basis of subgroup assessments deemed credible, VLCDs were less effective than less restrictive LCDs for weight loss at six months. However, this effect was explained by diet adherence. That is, among highly adherent patients on VLCDs, a clinically important reduction in weight was seen compared with studies with less adherent patients on VLCDs. Participants experienced no significant difference in quality of life at six months but did experience clinically important, but not statistically significant, worsening of quality of life and low density lipoprotein cholesterol at 12 months. Otherwise, no significant or clinically important between group differences were found in terms of adverse events or blood lipids at six and 12 months.
CONCLUSIONS
On the basis of moderate to low certainty evidence, patients adhering to an LCD for six months may experience remission of diabetes without adverse consequences. Limitations include continued debate around what constitutes remission of diabetes, as well as the efficacy, safety, and dietary satisfaction of longer term LCDs.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO CRD42020161795.
Topics: Blood Glucose; Combined Modality Therapy; Diabetes Mellitus, Type 2; Diet, Carbohydrate-Restricted; Dietary Carbohydrates; Glycated Hemoglobin; Humans; Insulin Resistance; Patient Compliance; Quality of Life; Randomized Controlled Trials as Topic; Time Factors; Treatment Outcome; Weight Loss
PubMed: 33441384
DOI: 10.1136/bmj.m4743 -
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 -
Nutrients Apr 2022We conducted a systematic review and meta-analysis of randomized clinical trials and pilot trial studies to compare the effectiveness of intermittent fasting (IF) and... (Meta-Analysis)
Meta-Analysis
We conducted a systematic review and meta-analysis of randomized clinical trials and pilot trial studies to compare the effectiveness of intermittent fasting (IF) and continuous calorie restriction (CCR) in overweight and obese people. The parameters included body mass index (BMI), body weight, and other metabolism-related indicators. A systematic search in PubMed, Embase, Cochrane Library, and Web of Science was conducted up to January 2022. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were used to measure the effectiveness. Publication bias was assessed using Egger's test. The stability of the results was evaluated using sensitivity analyses. The significance of body weight change (SMD = -0.21, 95% CI (-0.40, -0.02) = 0.028) was more significant after IF than CCR. There was no significant difference in BMI (SMD = 0.02, 95% CI (-0.16, 0.20) = 0.848) between IF and CCR. These findings suggest that IF may be superior to CCR for weight loss in some respects.
Topics: Body Weight; Caloric Restriction; Fasting; Humans; Overweight; Weight Loss
PubMed: 35565749
DOI: 10.3390/nu14091781