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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 -
Nutrients Jan 2021There has been a growing interest in the gastrointestinal system and its significance for autism spectrum disorder (ASD), including the significance of adopting a... (Meta-Analysis)
Meta-Analysis
There has been a growing interest in the gastrointestinal system and its significance for autism spectrum disorder (ASD), including the significance of adopting a gluten-free and casein-free (GFCF) diet. The objective was to investigate beneficial and safety of a GFCF diet among children with a diagnosis of ASD. We performed a systematic literature search in Medline, Embase, Cinahl, and the Cochrane Library up to January 2020 for existing systematic reviews and individual randomized controlled trials (RCTs). Studies were included if they investigated a GFCF diet compared to a regular diet in children aged 3 to 17 years diagnosed with ASD, with or without comorbidities. The quality of the identified existing reviews was assessed using A Measurement Tool to Assess Systematic Reviews (AMSTAR). The risk of bias in RCTs was assessed using the Cochrane Risk of Bias Tool, and overall quality of evidence was evaluated using Grades of Recommendation, Assessment, Development, and Evaluation (GRADE). We identified six relevant RCTs, which included 143 participants. The results from a random effect model showed no effect of a GFCF diet on clinician-reported autism core symptoms (standardized mean difference (SMD) -0.31 (95% Cl. -0.89, 0.27)), parent-reported functional level (mean difference (MD) 0.61 (95% Cl -5.92, 7.14)) or behavioral difficulties (MD 0.80 (95% Cl -6.56, 10.16)). On the contrary, a GFCF diet might trigger gastrointestinal adverse effects (relative risk (RR) 2.33 (95% Cl 0.69, 7.90)). The quality of evidence ranged from low to very low due to serious risk of bias, serious risk of inconsistency, and serious risk of imprecision. Clinical implications of the present findings may be careful consideration of introducing a GFCF diet to children with ASD. However, the limitations of the current literature hinder the possibility of drawing any solid conclusion, and more high-quality RCTs are needed. The protocol is registered at the Danish Health Authority website.
Topics: Adolescent; Autism Spectrum Disorder; Caseins; Child; Diet, Gluten-Free; Diet, Protein-Restricted; Humans
PubMed: 33573238
DOI: 10.3390/nu13020470 -
International Journal of Environmental... May 2022Food strategies are currently used to improve inflammation and oxidative stress conditions in chronic pain which contributes to a better quality of life for patients....
The Effectiveness of Intermittent Fasting, Time Restricted Feeding, Caloric Restriction, a Ketogenic Diet and the Mediterranean Diet as Part of the Treatment Plan to Improve Health and Chronic Musculoskeletal Pain: A Systematic Review.
Food strategies are currently used to improve inflammation and oxidative stress conditions in chronic pain which contributes to a better quality of life for patients. The main purpose of this systematic review is to analyze the effectiveness of different dietary strategies as part of the treatment plan for patients suffering from chronic pain and decreased health. PubMed, Web of Science, ProQuest, Scopus, Cumulative Index to Nursing & Allied Health Literature (CINAHL), Cambridge Core, and Oxford Academy databases were used to review and to appraise the literature. Randomized clinical trials (RCT), observational studies, and systematic reviews published within the last 6 years were included. The Physiotherapy Evidence Database (PEDro) scale, the PEDro Internal Validity (PVI), the Standard Quality Assessment Criteria for Evaluating Primary Research Papers from a variety of fields (QUALSYT), and the Quality Assessment Tool of Systematic Reviews scale were used to evaluate the risk of bias of the included studies. A total of 16 articles were included, of which 11 were RCTs and 5 were observational studies. Six of them showed an improvement in pain assessment, while two studies showed the opposite. Inflammation was shown to be decreased in four studies, while one did not show a decrease. The quality of life was shown to have improved in five studies. All of the selected studies obtained good methodological quality in their assessment scales. In the PVI, one RCT showed good internal validity, five RCTs showed moderate internal quality, while five of them were limited. Current research shows that consensus on the effects of an IF diet on pain improvement, in either the short or the long term, is lacking. A caloric restriction diet may be a good long term treatment option for people suffering from pain. Time restricted food and ketogenic diets may improve the quality of life in chronic conditions. However, more studies analyzing the effects of different nutritional strategies, not only in isolation but in combination with other therapies in the short and the long term, are needed.
Topics: Caloric Restriction; Chronic Pain; Diet, Ketogenic; Diet, Mediterranean; Fasting; Humans; Inflammation; Musculoskeletal Pain
PubMed: 35682282
DOI: 10.3390/ijerph19116698 -
Frontiers in Public Health 2022Diets containing red or processed meat are associated with a growing risk of digestive system cancers. Whether a plant-based diet is protective against cancer needs a... (Meta-Analysis)
Meta-Analysis
BACKGROUND AND OBJECTIVES
Diets containing red or processed meat are associated with a growing risk of digestive system cancers. Whether a plant-based diet is protective against cancer needs a high level of statistical evidence.
METHODS
We performed a meta-analysis of five English databases, including PubMed, Medline, Embase, Web of Science databases, and Scopus, on October 24, 2021 to identify published papers. Cohort studies or case-control studies that reported a relationship between plant-based diets and cancers of the digestive system were included. Summary effect-size estimates are expressed as Risk ratios (RRs) or Odds ratios (ORs) with 95% confidence intervals and were evaluated using random-effect models. The inconsistency index (I) and τ (Tau) index were used to quantify the magnitude of heterogeneity derived from the random-effects Mantel-Haenszel model.
RESULTS
The same results were found in cohort (adjusted RR = 0.82, 95% CI: 0.78-0.86, < 0.001, = 46.4%, Tau = 0.017) and case-control (adjusted OR = 0.70, 95% CI: 0.64-0.77, < 0.001, = 83.8%, Tau = 0.160) studies. The overall analysis concluded that plant-based diets played a protective role in the risk of digestive system neoplasms. Subgroup analyses demonstrated that the plant-based diets reduced the risk of cancers, especially pancreatic (adjusted RR = 0.71, 95% CI: 0.59-0.86, < 0.001, = 55.1%, Tau = 0.028), colorectal (adjusted RR = 0.76, 95% CI: 0.69-0.83, < 0.001, = 53.4%, Tau = 0.023), rectal (adjusted RR = 0.84, 95% CI: 0.78-0.91, < 0.001, = 1.6%, Tau = 0.005) and colon (adjusted RR = 0.88, 95% CI: 0.82-0.95, < 0.001, = 0.0%, Tau = 0.000) cancers, in cohort studies. The correlation between vegan and other plant-based diets was compared using Z-tests, and the results showed no difference.
CONCLUSIONS
Plant-based diets were protective against cancers of the digestive system, with no significant differences between different types of cancer.
SYSTEMATIC REVIEW REGISTRATION
https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022322276, Identifier: CRD42022322276.
Topics: Case-Control Studies; Cohort Studies; Diet; Diet, Vegetarian; Digestive System Neoplasms; Humans
PubMed: 35719615
DOI: 10.3389/fpubh.2022.892153 -
Nutrition Reviews Mar 2021Vegetarian and vegan diets are increasing in popularity. Although they provide beneficial health effects, they may also lead to nutritional deficiencies. Cognitive... (Meta-Analysis)
Meta-Analysis
CONTEXT
Vegetarian and vegan diets are increasing in popularity. Although they provide beneficial health effects, they may also lead to nutritional deficiencies. Cognitive impairment and mental health disorders have a high economic burden.
OBJECTIVE
A meta-analysis was conducted to examine the relationship between vegan or vegetarian diets and cognitive and mental health.
DATA SOURCES
PubMed, Scopus, ScienceDirect, and Proquest databases were examined from inception to July 2018.
STUDY SELECTION
Original observational or interventional human studies of vegan/vegetarian diets were selected independently by 2 authors.
DATA EXTRACTION
Raw means and standard deviations were used as continuous outcomes, while numbers of events were used as categorical outcomes.
RESULTS
Of 1249 publications identified, 13 were included, with 17 809 individuals in total. No significant association was found between diet and the continuous depression score, stress, well-being, or cognitive impairment. Vegans/vegetarians were at increased risk for depression (odds ratio = 2.142; 95%CI, 1.105-4.148) and had lower anxiety scores (mean difference = -0.847; 95%CI, -1.677 to -0.018). Heterogeneity was large, and thus subgroup analyses showed numerous differences.
CONCLUSIONS
Vegan or vegetarian diets were related to a higher risk of depression and lower anxiety scores, but no differences for other outcomes were found. Subgroup analyses of anxiety showed a higher risk of anxiety, mainly in participants under 26 years of age and in studies with a higher quality. More studies with better overall quality are needed to make clear positive or negative associations.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO registration no. CRD42018097204.
Topics: Anxiety; Cognition; Depression; Diet, Vegan; Diet, Vegetarian; Humans; Mental Health; Vegans; Vegetarians
PubMed: 32483598
DOI: 10.1093/nutrit/nuaa030 -
Clinical and Experimental Medicine Nov 2021Ketogenic diets are a widely known, yet controversial treatment for cancer patients. In this review, we summarize the clinical evidence for anti-tumor effects, as well... (Review)
Review
Ketogenic diets are a widely known, yet controversial treatment for cancer patients. In this review, we summarize the clinical evidence for anti-tumor effects, as well as the effects on anthropometry, quality of life, adverse events and adherence in cancer patients. In April 2019, a systematic search was conducted searching five electronic databases (EMBASE, Cochrane, PsychInfo, CINAHL and Medline) to find studies analyzing the use, effectiveness and potential harm of a ketogenic diet in cancer patients of any age as sole or complementary therapy. From all 19.211 search results, 46 publications concerning 39 studies with 770 patients were included in this systematic review. The therapy concepts included all forms of diets with reduced carbohydrate intake, that aimed to achieve ketosis for patients with different types of cancer. Most studies had a low quality, high risk of bias and were highly heterogeneous. There was no conclusive evidence for anti-tumor effects or improved OS. The majority of patients had significant weight loss and mild to moderate side effects. Adherence to the diet was rather low in most studies. Due to the very heterogeneous results and methodological limitations of the included studies, clinical evidence for the effectiveness of ketogenic diets in cancer patients is still lacking.
Topics: Complementary Therapies; Diet, Carbohydrate-Restricted; Diet, Ketogenic; Humans; Neoplasms; Quality of Life
PubMed: 33813635
DOI: 10.1007/s10238-021-00710-2 -
JAMA Pediatrics Mar 2023Despite advances in the understanding of dietary therapies in children with drug-resistant epilepsy, no quantitative comparison exists between different dietary... (Meta-Analysis)
Meta-Analysis
IMPORTANCE
Despite advances in the understanding of dietary therapies in children with drug-resistant epilepsy, no quantitative comparison exists between different dietary interventions.
OBJECTIVE
To evaluate the comparative efficacy and safety of various dietary therapies in childhood drug-resistant epilepsy.
DATA SOURCES
Systematic review and network meta-analysis (frequentist) of studies in PubMed, Embase, Cochrane, and Ovid published from inception to April 2022 using the search terms ketogenic diet, medium chain triglyceride diet, modified Atkins diet, low glycemic index therapy, and refractory epilepsy.
STUDY SELECTION
Randomized clinical trials comparing different dietary therapies (ketogenic diet, modified Atkins diet, and low glycemic index therapy) with each other or care as usual in childhood drug-resistant epilepsy were included. Abstract, title, and full text were screened independently by 2 reviewers.
DATA EXTRACTION AND SYNTHESIS
Data extraction was conducted following Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline. Cochrane risk-of-bias tool was used to assess the study quality. Effect sizes were calculated as odds ratio with 95% CI using random-effects model. The hierarchy of competing interventions was defined using the surface under the cumulative ranking curve.
MAIN OUTCOMES AND MEASURES
Short-term (≤3 months) 50% or higher and 90% or higher reduction in seizure frequency and treatment withdrawal due to adverse events were the primary efficacy and safety outcomes.
RESULTS
Of 2158 citations, 12 randomized clinical trials (907 patients) qualified for inclusion. In the short term, all dietary interventions were more efficacious than care as usual for 50% or higher seizure reduction (low glycemic index therapy: odds ratio [OR], 24.7 [95% CI, 5.3-115.4]; modified Atkins diet: OR, 11.3 [95% CI, 5.1-25.1]; ketogenic diet: OR, 8.6 [95% CI, 3.7-20.0]), while ketogenic diet (OR, 6.5 [95% CI, 2.3-18.0]) and modified Atkins diet (OR, 5.1 [95% CI, 2.2-12.0]) were better than care as usual for seizure reduction of 90% or higher. However, adverse event-related discontinuation rates were significantly higher for ketogenic diet (OR, 8.6 [95% CI, 1.8-40.6]) and modified Atkins diet (OR, 6.5 [95% CI, 1.4-31.2]) compared with care as usual. Indirectly, there was no significant difference between dietary therapies in efficacy and safety outcomes.
CONCLUSIONS AND RELEVANCE
This study found that all dietary therapies are effective in the short term. However, modified Atkins diet had better tolerability, higher probability for 50% or higher seizure reduction, and comparable probability for 90% or higher seizure reduction and may be a sounder option than ketogenic diet. Direct head-to-head comparison studies are needed to confirm these findings.
Topics: Child; Humans; Drug Resistant Epilepsy; Network Meta-Analysis; Diet, Ketogenic; Seizures; Diet, High-Protein Low-Carbohydrate; Treatment Outcome
PubMed: 36716045
DOI: 10.1001/jamapediatrics.2022.5648 -
JAMA Network Open Aug 2021The 2020 Dietary Guidelines Advisory Committee conducted a systematic review of existing research on diet and health to inform the current Dietary Guidelines for...
IMPORTANCE
The 2020 Dietary Guidelines Advisory Committee conducted a systematic review of existing research on diet and health to inform the current Dietary Guidelines for Americans. The committee answered this public health question: what is the association between dietary patterns consumed and all-cause mortality (ACM)?
OBJECTIVE
To ascertain the association between dietary patterns consumed and ACM.
EVIDENCE REVIEW
Guided by an analytical framework and predefined inclusion and exclusion criteria developed by the committee, the US Department of Agriculture's Nutrition Evidence Systematic Review (NESR) team searched PubMed, the Cochrane Central Register of Controlled Trials, and Embase and dual-screened the results to identify articles that were published between January 1, 2000, and October 4, 2019. These studies evaluated dietary patterns and ACM in participants aged 2 years and older. The NESR team extracted data from and assessed risk of bias in included studies. Committee members synthesized the evidence, developed conclusion statements, and graded the strength of the evidence supporting the conclusion statements.
FINDINGS
A total of 1 randomized clinical trial and 152 observational studies were included in the review. Studies enrolled adults and older adults (aged 17-84 years at baseline) from 28 countries with high or very high Human Development Index; 53 studies originated from the US. Most studies were well designed, used rigorous methods, and had low or moderate risks of bias. Precision, directness, and generalizability were demonstrated across the body of evidence. Results across studies were highly consistent. Evidence suggested that dietary patterns in adults and older adults that involved higher consumption of vegetables, fruits, legumes, nuts, whole grains, unsaturated vegetable oils, fish, and lean meat or poultry (when meat was included) were associated with a decreased risk of ACM. These healthy patterns were also relatively low in red and processed meat, high-fat dairy, and refined carbohydrates or sweets. Some of these dietary patterns also included intake of alcoholic beverages in moderation. Results based on additional analyses with confounding factors generally confirmed the robustness of main findings.
CONCLUSIONS AND RELEVANCE
In this systematic review, consuming a nutrient-dense dietary pattern was associated with reduced risk of death from all causes.
Topics: Cause of Death; Diet; Diet, Healthy; Humans; Nutrition Policy; United States
PubMed: 34463743
DOI: 10.1001/jamanetworkopen.2021.22277 -
Diabetes & Metabolism Journal May 2022Carbohydrate-restricted diets and intermittent fasting (IF) have been rapidly gaining interest among the general population and patients with cardiometabolic disease,... (Meta-Analysis)
Meta-Analysis Review
Effect of Carbohydrate-Restricted Diets and Intermittent Fasting on Obesity, Type 2 Diabetes Mellitus, and Hypertension Management: Consensus Statement of the Korean Society for the Study of Obesity, Korean Diabetes Association, and Korean Society of Hypertension.
Carbohydrate-restricted diets and intermittent fasting (IF) have been rapidly gaining interest among the general population and patients with cardiometabolic disease, such as overweight or obesity, diabetes, and hypertension. However, there are limited expert recommendations for these dietary regimens. This study aimed to evaluate the level of scientific evidence on the benefits and harms of carbohydrate-restricted diets and IF to make responsible recommendations. A meta-analysis and systematic literature review of 66 articles on 50 randomized controlled trials (RCTs) of carbohydrate-restricted diets and 10 articles on eight RCTs of IF was performed. Based on the analysis, the following recommendations are suggested. In adults with overweight or obesity, a moderately-low carbohydrate or low carbohydrate diet (mLCD) can be considered as a dietary regimen for weight reduction. In adults with type 2 diabetes mellitus, mLCD can be considered as a dietary regimen for improving glycemic control and reducing body weight. In contrast, a very-low carbohydrate diet (VLCD) and IF are recommended against in patients with diabetes. Furthermore, no recommendations are suggested for VLCD and IF in adults with overweight or obesity, and carbohydrate-restricted diets and IF in patients with hypertension. Here, we describe the results of our analysis and the evidence for these recommendations.
Topics: Adult; Diabetes Mellitus, Type 2; Diet, Carbohydrate-Restricted; Fasting; Humans; Hypertension; Obesity; Overweight; Republic of Korea
PubMed: 35656560
DOI: 10.4093/dmj.2022.0038 -
Evidence-based Dentistry Mar 2023This systematic review aimed to evaluate the influence of the nature of diet (vegan, vegetarian, and omnivore) on the oral health status in adults. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
This systematic review aimed to evaluate the influence of the nature of diet (vegan, vegetarian, and omnivore) on the oral health status in adults.
METHODS
This systematic review and meta-analysis was performed using the PRISMA guidelines. Electronic databases [PubMed, Embase, CENTRAL], online search engines (Google Scholar), research portals, and hand searches were performed systematically to identify studies. The last literature search was performed February 1st, 2021. Studies were included if they reported on the influence of the nature of diet on the oral health status (oral hygiene, periodontal health, dental status, and salivary function) in adults, by two investigators. Inter-investigator reliability was evaluated using Kappa (κ) statistics. PROSPERO registration number: CRD42020211567.
RESULTS
Twenty-two studies were included for data extraction and final analysis. The meta-analysis revealed that the bleeding on probing measure was higher in omnivores (Z = -4.057, p < 0.0001; 95% CI: -0.684, -0.238; I = 0.0%) and the overall periodontal health was significantly better in vegan/vegetarians than omnivores (Z = -2.632, p = 0.008; 95% CI: -0.274, -0.073; I = 29.7%). Vegan/vegetarians demonstrated more dental erosion (Z = 3.325, p = 0.001; 95% CI: 0.170, 0.659; I = 0.0%). In adults over 60 years old, the prevalence of caries was higher in omnivores (Z = 3.244, p = 0.001; 95% CI: 0.092, 0.371; I = 0.0%), while complete edentulism was more prevalent in vegetarians (Z = -4.147, p < 0.0001; 95% CI: -0.550, -0.197; I = 0.0%).
CONCLUSIONS
This review reveals that adults on an omnivore diet may be associated with a higher risk for periodontal problems and dental caries, while vegetarians/vegans may be associated with a higher risk for dental erosion.
Topics: Adult; Humans; Middle Aged; Vegans; Diet, Vegetarian; Dental Caries; Oral Health; Reproducibility of Results; Tooth Erosion; Diet; Vegetarians
PubMed: 36894675
DOI: 10.1038/s41432-023-00853-z