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Nutrition Reviews Mar 2019Vegetarian diets are consistently associated with improved health outcomes, and higher diet quality may contribute to improved health outcomes. This systematic review...
OBJECTIVE
Vegetarian diets are consistently associated with improved health outcomes, and higher diet quality may contribute to improved health outcomes. This systematic review aims to qualitatively compare the a priori diet quality of vegetarian and nonvegetarian diets.
METHODS
Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol, 2 online databases (Web of Science and PubMed) were searched for English language studies comparing diet quality among vegetarian and nonvegetarian adults using an a priori diet quality index. Two reviewers assessed study eligibility. Comparisons were made between total and component (when available) diet quality scores among the 12 studies meeting inclusion criteria.
CONCLUSIONS
Lacto-ovo vegetarians or vegans had higher overall diet quality (4.5-16.4 points higher on the Healthy Eating Index 2010 [HEI-2010]) compared with nonvegetarians in 9 of 12 studies. Higher HEI-2010 scores for vegetarians were driven by closer adherence to recommendations for total fruit, whole grains, seafood and plant protein, and sodium. However, nonvegetarians had closer adherence to recommendations for refined grains and total protein foods. Higher diet quality in vegetarian diets may partially explain improvements in health outcomes compared with nonvegetarians; however, more research controlling for known confounders like health consciousness is needed.
Topics: Adult; Diet; Diet, Vegan; Diet, Vegetarian; Female; Fruit; Humans; Male; Middle Aged; Minerals; Nutritive Value; Young Adult
PubMed: 30624697
DOI: 10.1093/nutrit/nuy067 -
Annals of Medicine 2019Fibromyalgia (FM) is a chronic non-degenerative disease, whose nutritional therapy seems controversial. This systematic review aimed to synthesize the knowledge about...
Fibromyalgia (FM) is a chronic non-degenerative disease, whose nutritional therapy seems controversial. This systematic review aimed to synthesize the knowledge about the effect of dietary interventions on patient-reported outcomes (PRO) and inflammation in patients with FM. Six electronic databases - PubMed, BioMed Central, Cochrane library, EMBASE, LILACS and ISI - were searched for clinical trials, in which a dietary intervention in patients with FM diagnosed was conducted. Quality of evidence assessment was measured in accordance with GRADE methodology. Seven clinical trials - 3 randomized controlled trials, 1 unrandomized clinical trial and 3 uncontrolled clinical trials were identified. Dietary approaches included gluten-free diet ( = 1), raw vegetarian diet ( = 2), low Fermentable oligo-, di- and monossacharides, alcohols and polyols (FODMAPs) diet ( = 1), hypocaloric diet ( = 2) and monosodium glutamate- and aspartame-free diet interventions ( = 1). The major PRO were pain and functional repercussion, with 5 out of 7 studies reporting an improvement. The progress in secondary outcomes was reported for fatigue (2/5 studies), sleep quality (2/3 studies), depression and anxiety (3/6 studies), quality of life (4/5 studies), gastrointestinal symptoms (1/2 studies) and inflammatory biomarkers (1/1 study). However, according to Cochrane Risk of Bias, these studies had poor statistical quality. Well-designed studies should be performed to investigate the dietary interventions effect on FM. Key messages Fibromyalgia (FM) is a chronic non-degenerative disease, whose nutritional therapy seems controversial but promising. Pain and functional repercussion in FM patients seem to improve with a hypocaloric diet, a raw vegetarian diet or a low FODMAPs diet, as much as quality of life, quality of sleep, anxiety and depression and inflammatory biomarkers. Existing studies in this subject are scarce and low quality, which does not allow conclusions to be drawn.
Topics: Chronic Disease; Diet, Carbohydrate-Restricted; Diet, Gluten-Free; Diet, Reducing; Fibromyalgia; Humans; Quality of Life
PubMed: 30735059
DOI: 10.1080/07853890.2018.1564360 -
Nutrients Nov 2022Caloric restriction and vegan diets have demonstrated protective effects for diabetes, however their role in improving clinically relevant outcomes has not been... (Meta-Analysis)
Meta-Analysis Review
Investigating the Effectiveness of Very Low-Calorie Diets and Low-Fat Vegan Diets on Weight and Glycemic Markers in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis.
Caloric restriction and vegan diets have demonstrated protective effects for diabetes, however their role in improving clinically relevant outcomes has not been summarized. Our aim was to evaluate the evidence for low-calorie diets (VLCD) and vegan diets on weight and glycemic control in the management of patients with Type 2 Diabetes. Database searches were conducted using Cochrane Library, MEDLINE (Ovid) and Embase. Systematic Review Registration: CRD42022310299. Methodological quality of studies was assessed using Cochrane RoB Tool for RCTs, Cochrane ROBINS-I RoB Tool for non-RCTs and NIH Quality Assessment tool for other studies. Sixteen studies with a total of 834 individuals were included and assessed to have a moderate to high risk of bias. Statistically significant changes in weight, BMI, and HbA1c were not observed in vegan diet cohorts. However, LDL cholesterol was significantly decreased by vegan diet. VLCDs significantly improved glycaemic control, with reductions in fasting glucose, pooled mean difference (MD) -1.51 mmol/L (95% CI -2.89, -0.13; = 0.03; 2 studies) and HbA1c, pooled MD -0.66% (95% CI -1.28, -0.03; = 0.04; 3 studies) compared to non-dietary therapy. Both diets suggested a trend towards improved weight loss and anthropometric markers vs. control. VLCD diet intervention is associated with improvement in glycaemia control in patients with Type 2 Diabetes.
Topics: Humans; Diet, Vegan; Diabetes Mellitus, Type 2; Glycated Hemoglobin; Caloric Restriction; Blood Glucose; Diet, Fat-Restricted; Biomarkers
PubMed: 36432557
DOI: 10.3390/nu14224870 -
Nutrients Jan 2018Heart failure (HF) is a complex syndrome and is recognized as the ultimate pathway of cardiovascular disease (CVD). Studies using nutritional strategies based on dietary... (Review)
Review
BACKGROUND
Heart failure (HF) is a complex syndrome and is recognized as the ultimate pathway of cardiovascular disease (CVD). Studies using nutritional strategies based on dietary patterns have proved to be effective for the prevention and treatment of CVD. Although there are studies that support the protective effect of these diets, their effects on the prevention of HF are not clear yet.
METHODS
We searched the Medline, Embase, and Cochrane databases for studies that examined dietary patterns, such as dietary approaches to stop hypertension (DASH diet), paleolithic, vegetarian, low-carb and low-fat diets and prevention of HF. No limitations were used during the search in the databases.
RESULTS
A total of 1119 studies were identified, 14 met the inclusion criteria. Studies regarding the Mediterranean, DASH, vegetarian, and Paleolithic diets were found. The Mediterranean and DASH diets showed a protective effect on the incidence of HF and/or worsening of cardiac function parameters, with a significant difference in relation to patients who did not adhere to these dietary patterns.
CONCLUSIONS
It is observed that the adoption of Mediterranean or DASH-type dietary patterns may contribute to the prevention of HF, but these results need to be analyzed with caution due to the low quality of evidence.
Topics: Adult; Aged; Aged, 80 and over; Diet, Healthy; Diet, Mediterranean; Diet, Paleolithic; Diet, Vegetarian; Dietary Approaches To Stop Hypertension; Feeding Behavior; Female; Heart Failure; Humans; Incidence; Male; Middle Aged; Nutritional Status; Nutritive Value; Primary Prevention; Protective Factors; Recommended Dietary Allowances; Risk Factors; Risk Reduction Behavior; Treatment Outcome
PubMed: 29320401
DOI: 10.3390/nu10010058 -
Journal of Affective Disorders Mar 2023Despite considerable advances in pharmacological and non-pharmacological treatments, mental health illnesses carry many economic and social burdens. Depression and... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Despite considerable advances in pharmacological and non-pharmacological treatments, mental health illnesses carry many economic and social burdens. Depression and anxiety are known as mental disorders which are highly prevalent worldwide. Previous studies have shown different results. This diet has attracted enormous interest.
OBJECTIVE
This is the first meta-analysis conducted to review systematically all trials to evaluating the effect of a low carbohydrate diet (LCD) on depression, and anxiety.
METHODS
PubMed, Web of Science, and Scopus have been searched until 9 September 2021. In total, 8 RCTs (n = 590) were carried out for evaluation the effects of LCDs on depression and anxiety were included. All the trials included in the analyses evaluated patients without a mood disorder. Random model effects meta-analysis was conducted. To evaluate the heterogeneity among the included studies. The egger test was used. Subgroup analyses performed based on regions, assessment methods, carbohydrate intake and duration of studies.
RESULTS
This study did not show any significant association between a low carbohydrate diet and the of anxiety (SMD = 0.19, 95 % CI -0.10, 0.47; P = 0.20) and also depression (SMD = 0.06, 95 % CI -0.11, 0.24; P = 0.49). If one of the studies is excluded, this diet significantly increases anxiety (SMD = 0.33, 95 % CI 0.12, 0.54; P ≤ 0.001). This study showed that this diet increases anxiety in studies with <26 % carbohydrate intake (SMD = 0.31; 95%CI 0.10, 0.52; P ≤ 0.001; I = 0.00, P = 0.52), in the Australia (SMD = 0.29; 95%CI 0.08, 0.49; P = 0.01; I = 0.00, P = 0.42), and in studies that used the Spielberger State Anxiety Inventory (SAI) to assess anxiety (SMD = 0.33; 95%CI 0.11, 0.54; P ≤ 0.001; I = 0.00, P = 0.54).
LIMITATIONS
One of the limitations of intervention studies examining the effect of diet is that it is difficult to blind people under intervention.
CONCLUSION
The present study did not demonstrate significant association between a low carbohydrate diet and improvement of depression and anxiety. More accurate studies are needed to reach definitive conclusions.
Topics: Humans; Depression; Anxiety; Anxiety Disorders; Diet, Carbohydrate-Restricted; Carbohydrates; Randomized Controlled Trials as Topic
PubMed: 36584702
DOI: 10.1016/j.jad.2022.12.030 -
The Cochrane Database of Systematic... Apr 2017Dietary changes are routinely recommended in people with chronic kidney disease (CKD) on the basis of randomised evidence in the general population and non-randomised... (Review)
Review
BACKGROUND
Dietary changes are routinely recommended in people with chronic kidney disease (CKD) on the basis of randomised evidence in the general population and non-randomised studies in CKD that suggest certain healthy eating patterns may prevent cardiovascular events and lower mortality. People who have kidney disease have prioritised dietary modifications as an important treatment uncertainty.
OBJECTIVES
This review evaluated the benefits and harms of dietary interventions among adults with CKD including people with end-stage kidney disease (ESKD) treated with dialysis or kidney transplantation.
SEARCH METHODS
We searched the Cochrane Kidney and Transplant Specialised Register (up to 31 January 2017) through contact with the Information Specialist using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE, and EMBASE; handsearching conference proceedings; and searching the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.
SELECTION CRITERIA
Randomised controlled trials (RCTs) or quasi-randomised RCTs of dietary interventions versus other dietary interventions, lifestyle advice, or standard care assessing mortality, cardiovascular events, health-related quality of life, and biochemical, anthropomorphic, and nutritional outcomes among people with CKD.
DATA COLLECTION AND ANALYSIS
Two authors independently screened studies for inclusion and extracted data. Results were summarised as risk ratios (RR) for dichotomous outcomes or mean differences (MD) or standardised MD (SMD) for continuous outcomes, with 95% confidence intervals (CI) or in descriptive format when meta-analysis was not possible. Confidence in the evidence was assessed using GRADE.
MAIN RESULTS
We included 17 studies involving 1639 people with CKD. Three studies enrolled 341 people treated with dialysis, four studies enrolled 168 kidney transplant recipients, and 10 studies enrolled 1130 people with CKD stages 1 to 5. Eleven studies (900 people) evaluated dietary counselling with or without lifestyle advice and six evaluated dietary patterns (739 people), including one study (191 people) of a carbohydrate-restricted low-iron, polyphenol enriched diet, two studies (181 people) of increased fruit and vegetable intake, two studies (355 people) of a Mediterranean diet and one study (12 people) of a high protein/low carbohydrate diet. Risks of bias in the included studies were generally high or unclear, lowering confidence in the results. Participants were followed up for a median of 12 months (range 1 to 46.8 months).Studies were not designed to examine all-cause mortality or cardiovascular events. In very-low quality evidence, dietary interventions had uncertain effects on all-cause mortality or ESKD. In absolute terms, dietary interventions may prevent one person in every 3000 treated for one year avoiding ESKD, although the certainty in this effect was very low. Across all 17 studies, outcome data for cardiovascular events were sparse. Dietary interventions in low quality evidence were associated with a higher health-related quality of life (2 studies, 119 people: MD in SF-36 score 11.46, 95% CI 7.73 to 15.18; I = 0%). Adverse events were generally not reported.Dietary interventions lowered systolic blood pressure (3 studies, 167 people: MD -9.26 mm Hg, 95% CI -13.48 to -5.04; I = 80%) and diastolic blood pressure (2 studies, 95 people: MD -8.95, 95% CI -10.69 to -7.21; I = 0%) compared to a control diet. Dietary interventions were associated with a higher estimated glomerular filtration rate (eGFR) (5 studies, 219 people: SMD 1.08; 95% CI 0.26 to 1.97; I = 88%) and serum albumin levels (6 studies, 541 people: MD 0.16 g/dL, 95% CI 0.07 to 0.24; I = 26%). A Mediterranean diet lowered serum LDL cholesterol levels (1 study, 40 people: MD -1.00 mmol/L, 95% CI -1.56 to -0.44).
AUTHORS' CONCLUSIONS
Dietary interventions have uncertain effects on mortality, cardiovascular events and ESKD among people with CKD as these outcomes were rarely measured or reported. Dietary interventions may increase health-related quality of life, eGFR, and serum albumin, and lower blood pressure and serum cholesterol levels.Based on stakeholder prioritisation of dietary research in the setting of CKD and preliminary evidence of beneficial effects on risks factors for clinical outcomes, large-scale pragmatic RCTs to test the effects of dietary interventions on patient outcomes are required.
Topics: Adult; Cardiovascular Diseases; Diet, Carbohydrate-Restricted; Diet, Mediterranean; Diet, Protein-Restricted; Disease Progression; Fruit; Humans; Kidney Failure, Chronic; Kidney Transplantation; Quality of Life; Randomized Controlled Trials as Topic; Renal Insufficiency, Chronic; Renal Replacement Therapy; Vegetables
PubMed: 28434208
DOI: 10.1002/14651858.CD011998.pub2 -
Pediatrics Jun 2017Children with autism spectrum disorder (ASD) frequently use special diets or receive nutritional supplements to treat ASD symptoms. (Review)
Review
CONTEXT
Children with autism spectrum disorder (ASD) frequently use special diets or receive nutritional supplements to treat ASD symptoms.
OBJECTIVES
Our objective was to evaluate the effectiveness and safety of dietary interventions or nutritional supplements in ASD.
DATA SOURCES
Databases, including Medline and PsycINFO.
STUDY SELECTION
Two investigators independently screened studies against predetermined criteria.
DATA EXTRACTION
One investigator extracted data with review by a second investigator. Investigators independently assessed the risk of bias and strength of evidence (SOE) (ie, confidence in the estimate of effects).
RESULTS
Nineteen randomized controlled trials (RCTs), 4 with a low risk of bias, evaluated supplements or variations of the gluten/casein-free diet and other dietary approaches. Populations, interventions, and outcomes varied. Ω-3 supplementation did not affect challenging behaviors and was associated with minimal harms (low SOE). Two RCTs of different digestive enzymes reported mixed effects on symptom severity (insufficient SOE). Studies of other supplements (methyl B, levocarnitine) reported some improvements in symptom severity (insufficient SOE). Studies evaluating gluten/casein-free diets reported some parent-rated improvements in communication and challenging behaviors; however, data were inadequate to make conclusions about the body of evidence (insufficient SOE). Studies of gluten- or casein-containing challenge foods reported no effects on behavior or gastrointestinal symptoms with challenge foods (insufficient SOE); 1 RCT reported no effects of camel's milk on ASD severity (insufficient SOE). Harms were disparate.
LIMITATIONS
Studies were small and short-term, and there were few fully categorized populations or concomitant interventions.
CONCLUSIONS
There is little evidence to support the use of nutritional supplements or dietary therapies for children with ASD.
Topics: Autism Spectrum Disorder; Child; Diet, Gluten-Free; Dietary Supplements; Enzyme Therapy; Fatty Acids, Omega-3; Humans; Randomized Controlled Trials as Topic
PubMed: 28562286
DOI: 10.1542/peds.2017-0346 -
International Journal of Environmental... Mar 2021(1) Background: The purpose of the current meta-analysis was to investigate any positive or negative effects of ketogenic diets in athletes and provide an assessment of... (Meta-Analysis)
Meta-Analysis Review
(1) Background: The purpose of the current meta-analysis was to investigate any positive or negative effects of ketogenic diets in athletes and provide an assessment of the size of these effects. (2) Methods: Databases were used to select relevant studies up to January 2021 regarding the effects of ketogenic diets in athletes. Inclusion criteria were as follows: data before and after ketogenic diet use, being randomized controlled trials and presenting ketogenic diets and assessments of ketone status. Study subjects were required to be professional athletes. Review studies, pilot studies, and studies in which non-athletes were included were excluded from this meta-analysis. The outcome effect sizes in these selected studies were calculated by using the standardized mean difference statistic. (3) Results: Eight studies were selected for this meta-analysis. Athletes who consumed the ketogenic diet had reduced body fat percentages, respiratory exchange rates, and increased total cholesterol compared to athletes who did not consume this diet. However, body mass index, cardiorespiratory fitness, heart rate, HDL cholesterol, glucose level, and insulin level were unaffected by the diet. (4) Conclusions: Ketogenic diets had a beneficial effect by decreasing body fat percentage, but athletes with high total cholesterol level need to be monitored when instituting a ketogenic diet. Our study sample size was limited; therefore, additional studies may be needed to confirm the current findings. Further studies need to be conducted on changes in LDL cholesterol, HDL cholesterol, total cholesterol and ratio of LDL to HDL cholesterol.
Topics: Adipose Tissue; Athletes; Cholesterol, HDL; Diet; Diet, Ketogenic; Humans
PubMed: 33809153
DOI: 10.3390/ijerph18062912 -
The British Journal of Nutrition Mar 2024Plant-based diets have emerged as athletic performance enhancers for various types of exercise. Therefore, the present study evaluated the effectiveness of plant-based... (Meta-Analysis)
Meta-Analysis Review
Plant-based diets have emerged as athletic performance enhancers for various types of exercise. Therefore, the present study evaluated the effectiveness of plant-based diets on aerobic and strength/power performances, as well as on BMI of physically active individuals. This systematic review and meta-analysis was conducted and reported according to the guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. A systematic search of electronic databases, including PubMed, Web of Science and SPORTDiscus, was performed. On the basis of the search and inclusion criteria, four and six studies evaluating the effects of plant-based diets on aerobic and strength/power performances in humans were, respectively, included in the systematic review and meta-analysis. Plant-based diets had a moderate but positive effect on aerobic performance (0·55; 95 % CI 0·29, 0·81) and no effect on strength/power performance (-0·30; 95 % CI -0·67, 0·07). The altogether analyses of both aerobic and strength/power exercises revealed that athletic performance was unchanged (0·01; 95 % CI -0·21, 0·22) in athletes who adopted plant-based diets. However, a small negative effect on BMI (-0·27; 95 % CI -0·40, -0·15) was induced by these diets. The results indicate that plant-based diets have the potential to exclusively assist aerobic performance. On the other hand, these diets do not jeopardise strength/power performance. Overall, the predicted effects of plant-based diets on physical performance are impactless, even though the BMI of their adherents is reduced.
Topics: Humans; Diet, Plant-Based; Athletic Performance; Diet; Exercise; Exercise Therapy; Muscle Strength
PubMed: 37869973
DOI: 10.1017/S0007114523002258 -
Redox Biology Jun 2021Oxidative stress and inflammation are known to play a critical role in ageing and chronic disease development and could therefore represent important targets for...
INTRODUCTION
Oxidative stress and inflammation are known to play a critical role in ageing and chronic disease development and could therefore represent important targets for developing dietary strategies for disease prevention. We aimed to systematically review the results from observational studies and intervention trials published in the last 5 years on the associations between dietary patterns and biomarkers of oxidative stress and inflammation.
METHODS
A systematic search of the PubMed, MEDLINE and Web of Science (January 2015 to October 2020) was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Methodological quality of selected studies was evaluated based on the NUTRIGRADE and BIOCROSS assessment tools.
RESULTS
In total, 29 studies among which 16 observational studies and 13 intervention studies were found eligible for review. Overall, results indicated an inverse association between plant-based diets - the Mediterranean and Dietary Approaches to Stop Hypertension (DASH) diet - and oxidative stress and proinflammatory biomarkers. In observational studies, inverse associations were further revealed for the vegetarian diet, the USDA Healthy Eating Index (HEI) - based diet and the paleolithic diet, whereas a positive association was seen for western and fast food diets. Quality assessment suggested that majority of dietary intervention studies (n = 12) were of low to moderate quality.
CONCLUSIONS
This study provides evidence that the plant-based dietary patterns are associated with lowered levels of oxidative stress and inflammation and may provide valid means for chronic disease prevention. Future large-scale intervention trials using validated biomarkers are warranted to confirm these findings.
Topics: Biomarkers; Diet; Diet, Healthy; Dietary Approaches To Stop Hypertension; Humans; Inflammation; Oxidative Stress
PubMed: 33541846
DOI: 10.1016/j.redox.2021.101869