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Examining the Association between Coffee Intake and the Risk of Developing Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis.
Lee, JY, Yau, CY, Loh, CYL, Lim, WS, Teoh, SE, Yau, CE, Ong, C, Thumboo, J, Namasivayam, VSO, Ng, QX
Nutrients. 2023;15(22)
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Irritable bowel syndrome (IBS) is a highly prevalent disorder of brain–gut interaction with a significant impact on quality of life and social functioning. Diet has been implicated in the pathophysiology of IBS as well as disease flares. A significant proportion of IBS patients experience food-related symptoms associated with consuming or eliminating certain foods. This study's aim was to determine if there is an association between coffee intake and the likelihood of developing IBS. This study was a systematic review and meta-analysis of eight studies with 432,022 participants. Results showed that coffee drinkers (any intake) may have a decreased risk of developing IBS compared to controls. However, these findings must be interpreted in light of several shortcomings. Authors concluded that future studies should (1) prioritise high-quality prospective cohort studies with well-documented coffee consumption (and exposure) and track the development of incident IBS in previously healthy individuals over time, and (2) investigate biological mechanisms.
Abstract
Irritable bowel syndrome (IBS) is a highly prevalent disorder of brain-gut interaction with a significant impact on quality of life. Coffee is a widely consumed beverage with numerous bioactive compounds that have potential effects on human health and disease states. Current studies on the effect of regular coffee consumption on the risk of developing IBS symptoms have yielded conflicting results. This systematic review and meta-analysis aimed to determine whether coffee intake is associated with developing IBS. A systematic literature search was performed in three electronic databases, namely PubMed, EMBASE, and The Cochrane Library, from inception until 31 March 2023. All original studies reporting associations between coffee intake and IBS were considered for inclusion. Odds ratios (ORs) were calculated for each study, and estimates were pooled, and where appropriate, 95% confidence intervals (95% CI) and p-values were calculated. Eight studies comprising 432,022 patients were included in the final meta-analysis. Using a fixed-effects model, coffee drinkers (any intake) had a reduced likelihood of developing IBS compared to controls, with a pooled OR of 0.84 (95% CI: 0.80 to 0.84). Sensitivity analysis confirmed the stability of the estimates. Future research should prioritise prospective cohort studies that are robust and closely track the development of incident IBS in previously healthy individuals.
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Mediterranean Diet-Based Interventions to Improve Anthropometric and Obesity Indicators in Children and Adolescents: A Systematic Review with Meta-Analysis of Randomized Controlled Trials.
López-Gil, JF, García-Hermoso, A, Sotos-Prieto, M, Cavero-Redondo, I, Martínez-Vizcaíno, V, Kales, SN
Advances in nutrition (Bethesda, Md.). 2023;14(4):858-869
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Globally, excess weight (overweight or obesity) in childhood represents a major public health threat, especially in Europe. Among healthy dietary patterns, the Mediterranean diet (MedDiet) has been recognised worldwide due to its distinctive health benefits. The aim of this study was to evaluate the effects of MedDiet-based interventions on anthropometric and obesity indicators among children and adolescents. This study was a systematic review and meta-analysis of fifteen randomised controlled trials. The studies included a total of 7184 participants (intervention groups: n = 3356) aged between 3 and 18 years. Results showed that the MedDiet-based interventions in a trial setting can be safely conducted in children and adolescents. In fact, the MedDiet-based interventions decreased body mass index and the percentage of obesity in children and adolescents. Authors conclude that their findings highlight the efficacy of MedDiet-based interventions as a useful tool in reversing the high prevalence of obesity.
Abstract
To our knowledge, no systematic review with meta-analysis has separately synthesized the effects of Mediterranean diet-based interventions in children and adolescents in relation to the effects on anthropometric measures. A better understanding of the effects of Mediterranean diet-based interventions on anthropometric variables could facilitate their implementation in efforts to prevent obesity in the young population. The aim of the present meta-analysis was to evaluate the effects of Mediterranean diet-based interventions on anthropometric and obesity indicators among children and adolescents. Four databases were systematically searched (PubMed, Scopus, Web of Science, and Cochrane Database of Systematic Reviews), including all studies up until 15 March, 2023. Eligible articles were randomized controlled trials measuring the effect of an intervention based on the promotion of the Mediterranean diet and obesity-associated parameters. The effect size of each study was estimated by Cohen's d for continuous variables or risk difference for categorical variables. Compared to the control group, the Mediterranean diet-based interventions showed small and significant reductions in body mass index (d = -0.14; 95% CI: -0.26, -0.01; I2 = 77.52%). Participants in the Mediterranean diet-based interventions had a significant reduction in the percentage of obesity (risk difference = 0.12; 95% CI: 0.01, 0.23; I2 = 84.56%) in comparison with the control group. Interventions had greater effects when aiming at participants with excess weight (that is, overweight or obesity), both for body mass index, waist circumference, waist-to-height ratio, percentage of obesity, and percentage of abdominal obesity. Mediterranean diet-based interventions have a significant effect on reducing the body mass index as well as reducing obesity in children and adolescents (aged 3-18 y). This trial was registered at PROSPERO as CRD42023386789.
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The effect of healthy dietary patterns on male semen quality: a systematic review and meta-analysis.
Cao, LL, Chang, JJ, Wang, SJ, Li, YH, Yuan, MY, Wang, GF, Su, PY
Asian journal of andrology. 2022;24(5):549-557
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Infertility has been identified by the World Health Organization as a worldwide problem. The analysis of semen quality is key in assessing male fertility. The aim of this study was to explore the effect of healthy dietary patterns on male semen quality. This study is a systematic review and meta-analysis of six articles. The six articles were cross-sectional studies involving 1244 subjects, however, 708 subjects with the lowest and highest adherence to a healthy dietary pattern were included in the meta-analysis. Results show that the sperm concentration, progressive sperm motility, and total sperm count were significantly higher in the group with high consumption of a healthy dietary pattern than those in the group with low consumption; however, there wasn’t a clear relationship between normal sperm morphology, total sperm motility, and semen volume. Authors conclude that dietary interventions should be considered in clinical work as part of the therapies improving male semen quality.
Expert Review
Conflicts of interest:
None
Take Home Message:
- This Systematic Review and Meta Analysis showed that healthy dietary patterns had beneficial effects on sperm concentration, total sperm count, and progressive sperm motility in males, which affect male fertility.
- Authors concluded that healthy dietary patterns may promote male reproductive health and thus improve semen quality in the population.
- Healthy dietary patterns meant the Mediterranean diet for 4 out of 6 studies. All healthy diet patterns were determined by the authors to be rich in plant-based foods, where saturated fats provide only a small percentage of the total energy intake.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
- This study aimed to determine the effects of healthy dietary patterns on semen quality.
Methodology
- This meta-analysis was performed following PRISMA guidelines and included 6 cross-sectional studies with 1244 participants
- The included cross-sectional studies examined the influence of the Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and prudent diet patterns on semen quality parameters.
- In 4 of the studies participants were divided into groups based on their scores for the Mediterranean diet from low to high adherence.
- 2 studies examined the DASH diet and the prudent diet and used food frequency questionnaires to compare high consumption with low consumption of healthy dietary patterns.
- The PICOS (Participants, Intervention, Comparison, Outcomes, and Study design) criteria that were used to structure the research question.
- 11 Checklists were used to assess the quality of included studies.
Results:
By comparing high consumption with low consumption of healthy dietary patterns, the results of the meta-analysis showed:
- significantly higher sperm concentrations (mean difference [MD] = 6.88 × 106 ml−1, 95% confidence interval [CI]: 1.26 × 106 ml−1–12.49 × 106 ml−1; P < 0.05)
- significant increase in total sperm count (MD = 16.70 × 106, 95% CI: 2.37 × 106–31.03 × 106; P < 0.05)
- significant increase in progressive sperm motility (MD = 5.85%, 95% CI: 2.59%–9.12%; P < 0.01) but there was no significant correlation between healthy dietary patterns and total sperm motility (MD: 6.86%, 95% CI: −0.25%–13.96%; P > 0.05).
- there was no significant association between a healthy dietary pattern and normal sperm morphology (MD: 0.28%, 95% CI: −0.33%–0.90%; P > 0.05)
- there was no significant association between a healthy dietary pattern and semen volume (MD: 0.04 ml, 95% CI: −0.20 ml–0.28 ml; P > 0.05).
Limitations:
- Included studies were all cross-sectional studies, and it is impossible to determine the causal relationship between the high intake of healthy dietary patterns and semen quality.
- The number of studies included was small, and there was not enough literature to support authors in drawing reliable conclusions.
- No comparison was made between specific diets such as dash vs Mediterranean.
Clinical practice applications:
- The authors concluded that dietary interventions should be considered in clinical work as part of the therapies improving male semen quality.
- Dietary interventions for men should be included as part of preconceptional clinical management,
- Dietary interventions for men should also be considered in infertility clinical management.
Considerations for future research:
- Randomised Clinical Trials should be conducted to build on these findings.
Abstract
The incidence of infertility has recently risen. Semen quality is an important male fertility indicator, and dietary factors can affect semen quality. We conducted this systematic review and meta-analysis to determine the effects of healthy dietary patterns on semen quality. A literature search was conducted in 3 databases (Embase, Web of Science and PubMed) on August 21, 2021. The included cross-sectional studies examined the influence of the Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and prudent diet patterns on semen quality parameters; six studies (1244 subjects) were included. By comparing high consumption with low consumption of healthy dietary patterns, the results of the meta-analysis showed significantly higher sperm concentrations (mean difference [MD] = 6.88 × 106 ml-1, 95% confidence interval [CI]: 1.26 × 106 ml-1-12.49 × 106 ml-1; P < 0.05), a significant increase in total sperm count (MD = 16.70 × 106, 95% CI: 2.37 × 106-31.03 × 106; P < 0.05), and a significant increase in progressive sperm motility (MD = 5.85%, 95% CI: 2.59%-9.12%; P < 0.01). The sperm concentration, progressive sperm motility, and total sperm count were significantly higher in men with higher versus lower consumption of healthy dietary patterns. However, the results must be interpreted with caution.
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Ultra-Processed Food Consumption and Mental Health: A Systematic Review and Meta-Analysis of Observational Studies.
Lane, MM, Gamage, E, Travica, N, Dissanayaka, T, Ashtree, DN, Gauci, S, Lotfaliany, M, O'Neil, A, Jacka, FN, Marx, W
Nutrients. 2022;14(13)
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Poor dietary quality is well established as a potentially modifiable risk factor for mental disorders. The NOVA food classification system was recently developed to enable the categorisation of food items based on distinctive levels of processing. The aim of this study was to synthesise and provide quantitative analyses of the most up-to-date evidence assessing associations between consumption of ultra-processed food, as defined by the NOVA food classification system, and mental disorders. This study is systematic review and meta-analysis of 17 studies with a total of 385,541 participants. The studies were 15 cross-sectional and 2 prospectively designed studies. Results show that ultra-processed food consumption is bidirectionally associated with adverse mental health. In fact, greater intake of ultra-processed food was associated with increased odds of depressive and anxiety symptoms, both when these outcomes were assessed together as well as separately. Authors conclude that further prospective and experimental studies are required to better determine directionality and causality and ensure that global preventative and treatment strategies are efficacious and appropriate.
Abstract
Since previous meta-analyses, which were limited only to depression and by a small number of studies available for inclusion at the time of publication, several additional studies have been published assessing the link between ultra-processed food consumption and depression as well as other mental disorders. We aimed to build on previously conducted reviews to synthesise and meta-analyse the contemporary evidence base and clarify the associations between the consumption of ultra-processed food and mental disorders. A total of 17 observational studies were included (n = 385,541); 15 cross-sectional and 2 prospective. Greater ultra-processed food consumption was cross-sectionally associated with increased odds of depressive and anxiety symptoms, both when these outcomes were assessed together (common mental disorder symptoms odds ratio: 1.53, 95%CI 1.43 to 1.63) as well as separately (depressive symptoms odds ratio: 1.44, 95%CI 1.14 to 1.82; and, anxiety symptoms odds ratio: 1.48, 95%CI 1.37 to 1.59). Furthermore, a meta-analysis of prospective studies demonstrated that greater ultra-processed food intake was associated with increased risk of subsequent depression (hazard ratio: 1.22, 95%CI 1.16 to 1.28). While we found evidence for associations between ultra-processed food consumption and adverse mental health, further rigorously designed prospective and experimental studies are needed to better understand causal pathways.
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An updated systematic review and meta-analysis on adherence to mediterranean diet and risk of cancer.
Morze, J, Danielewicz, A, Przybyłowicz, K, Zeng, H, Hoffmann, G, Schwingshackl, L
European journal of nutrition. 2021;60(3):1561-1586
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The development of cancer is associated with a number of risk factors, including smoking, obesity, sedentary lifestyles, alcohol consumption, infections, pollution, and dietary imbalances. Based on previous research, optimal consumption of fruits, vegetables, and whole grains, along with reduced consumption of red and processed meat, reduces cancer risk. According to this systematic review and meta-analysis, adherence to the Mediterranean diet is associated with lower cancer mortality and site-specific cancer development. A Mediterranean diet includes fruits, vegetables, nuts, legumes, fish, whole grains, extra virgin olive oil, and low amounts of red meat, processed meat, egg, and dairy, along with moderate amounts of red wine. According to this systematic review and meta-analysis, adherence to the Mediterranean diet reduces the risk of cancer mortality and the risk of developing cancers specific to the site, such as colorectal cancer, bladder cancer, gastric cancer, and lung cancer. Among the components of the Mediterranean diet, fruits, vegetables, and whole grains have been shown to reduce cancer risk. Bioactive substances found in Mediterranean diet components require additional robust studies to evaluate their benefits. A healthcare professional can use the results of this study to make clinical decisions and recommend therapeutic interventions to cancer patients.
Abstract
PURPOSE The aim of current systematic review was to update the body of evidence on associations between adherence to the Mediterranean diet (MedDiet) and risk of cancer mortality, site-specific cancer in the general population; all-cause, and cancer mortality as well as cancer reoccurrence among cancer survivors. METHODS A literature search for randomized controlled trials (RCTs), case-control and cohort studies published up to April 2020 was performed using PubMed and Scopus. Study-specific risk estimates for the highest versus lowest adherence to the MedDiet category were pooled using random-effects meta-analyses. Certainty of evidence from cohort studies and RCTs was evaluated using the NutriGrade scoring system. RESULTS The updated search revealed 44 studies not identified in the previous review. Altogether, 117 studies including 3,202,496 participants were enclosed for meta-analysis. The highest adherence to MedDiet was inversely associated with cancer mortality (RRcohort: 0.87, 95% CI 0.82, 0.92; N = 18 studies), all-cause mortality among cancer survivors (RRcohort: 0.75, 95% CI 0.66, 0.86; N = 8), breast (RRobservational: 0.94, 95% CI 0.90, 0.97; N = 23), colorectal (RRobservational: 0.83, 95% CI 0.76, 0.90; N = 17), head and neck (RRobservational: 0.56, 95% CI 0.44, 0.72; N = 9), respiratory (RRcohort: 0.84, 95% CI 0.76, 0.94; N = 5), gastric (RRobservational: 0.70, 95% CI 0.61, 0.80; N = 7), bladder (RRobservational: 0.87, 95% CI 0.76, 0.98; N = 4), and liver cancer (RRobservational: 0.64, 95% CI 0.54, 0.75; N = 4). Adhering to MedDiet did not modify risk of blood, esophageal, pancreatic and prostate cancer risk. CONCLUSION In conclusion, our results suggest that highest adherence to the MedDiet was related to lower risk of cancer mortality in the general population, and all-cause mortality among cancer survivors as well as colorectal, head and neck, respiratory, gastric, liver and bladder cancer risks. Moderate certainty of evidence from cohort studies suggest an inverse association for cancer mortality and colorectal cancer, but most of the comparisons were rated as low or very low certainty of evidence.
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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.
Ge, L, Sadeghirad, B, Ball, GDC, da Costa, BR, Hitchcock, CL, Svendrovski, A, Kiflen, R, Quadri, K, Kwon, HY, Karamouzian, M, et al
BMJ (Clinical research ed.). 2020;369:m696
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Dietary recommendations to combat obesity and its associated risk for heart disease are extensive. Many different diets and patterns of eating are being tried by millions of people, however no systematic review comparing their effectiveness has been performed. This systematic review and meta-analysis aimed to determine the effectiveness of 14 popular diets and diets which restrict certain nutrients on weight loss and heart disease risk. The results identified 121 studies with 21942 patients for inclusion. The Atkins diet, the Zone diet and the Dietary Approaches to Stop Hypertension (DASH) diet were the most effective for weight loss and for reducing blood pressure. Low carbohydrate and low-fat diets achieved similar weight loss when compared to a normal diet. Low carbohydrate diets had less effect on heart disease risk factors than low fat and moderate macronutrient diets. There were no improvements in good cholesterol with any of the diets. Interestingly any benefits on weight loss for any of the diets disappeared after 12 months and this was also observed for heart disease risk, except in those on the Mediterranean diet. It was concluded that most diets show improvements to weight loss and heart disease risk factors over 6 months, however these are largely unsustainable after 12 months. Differences between diets are small and healthcare practitioners could use this study to recommend any number of diets to achieve weight loss and the Mediterranean diet in particular to decrease heart disease risk. However, it is important to understand that this may be a short-term fix and at 12 months patients need to be assessed to ensure that weight loss is sustained.
Abstract
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 v 4.37 kg, both moderate certainty) and reduction in systolic blood pressure (5.14 mm Hg, moderate certainty v 5.05 mm Hg, low certainty) and diastolic blood pressure (3.21 v 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 v 7.08 mg/dL, moderate certainty v 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.
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Influence of diet on the gut microbiome and implications for human health.
Singh, RK, Chang, HW, Yan, D, Lee, KM, Ucmak, D, Wong, K, Abrouk, M, Farahnik, B, Nakamura, M, Zhu, TH, et al
Journal of translational medicine. 2017;15(1):73
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Gut microbiome plays an important role in modulating the risk of many chronic diseases through its impact on host immunity and metabolic health. Diet, in turn, can alter the composition of the microbiota. This paper reviewed current understanding of the effects of common dietary components and three select diets on gut microbiota composition and host health. Dietary components included plant and animal protein, saturated and unsaturated fats, digestible and non-digestible carbohydrates, probiotics and polyphenols. The diets included Western diet, gluten-free diet and Mediterranean diet. Based on the reviewed papers, the authors concluded that diet can modify the intestinal microbiome, which in turn has a profound impact on overall health. The impact can be beneficial or detrimental, depending on the abundance and identity of microbial populations and the nature of their interactions with the host. The authors also state that further research using large, long-term clinical trials to evaluate a greater variety of food components would be helpful in making specific dietary recommendations to patients.
Abstract
Recent studies have suggested that the intestinal microbiome plays an important role in modulating risk of several chronic diseases, including inflammatory bowel disease, obesity, type 2 diabetes, cardiovascular disease, and cancer. At the same time, it is now understood that diet plays a significant role in shaping the microbiome, with experiments showing that dietary alterations can induce large, temporary microbial shifts within 24 h. Given this association, there may be significant therapeutic utility in altering microbial composition through diet. This review systematically evaluates current data regarding the effects of several common dietary components on intestinal microbiota. We show that consumption of particular types of food produces predictable shifts in existing host bacterial genera. Furthermore, the identity of these bacteria affects host immune and metabolic parameters, with broad implications for human health. Familiarity with these associations will be of tremendous use to the practitioner as well as the patient.