-
1.
Effect of Dietary Intervention, with or without Cointerventions, on Inflammatory Markers in Patients with Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis.
Hall, RL, George, ES, Tierney, AC, Reddy, AJ
Advances in nutrition (Bethesda, Md.). 2023;14(3):475-499
-
-
-
Free full text
Plain language summary
Multiple factors, including toxic accumulation of fatty acids in adipose tissue; impaired microbial functioning of the gut; and an imbalance of inflammatory mediators, contribute to a progressed inflammatory state in the liver. The aim of this study was to assess the cumulative effect of evidence regarding the effect of dietary intervention, with or without cointerventions, on the inflammatory profile of adults diagnosed with non-alcoholic fatty liver disease (NAFLD). This study was a systematic review and meta-analysis of forty-four randomised controlled trials. A total of 2579 participants with NAFLD were enrolled in the studies, of whom 2497 participants were analysed. Results (meta-analysis) showed that a hypocaloric diet, when used alone or with supplementation, was the most effective dietary intervention for the improvement of NAFLD-implicated inflammatory markers, adiponectin, and leptin. Whereas isocaloric or energy-balanced dietary interventions provided improvements to the same inflammatory cytokines and adipokines when coupled with supplementation but the benefit was less. Authors conclude that larger sample sizes and longer duration studies are needed in order to better determine the effectiveness of dietary intervention on a NAFLD population.
Abstract
Nonalcoholic fatty liver disease (NAFLD) encompasses a spectrum of disease from simple steatosis to nonalcoholic steatohepatitis, with inflammatory cytokines and adipokines identified as drivers of disease progression. Poor dietary patterns are known to promote an inflammatory milieu, although the effects of specific diets remain largely unknown. This review aimed to gather and summarize new and existing evidence on the effect of dietary intervention on inflammatory markers in patients with NAFLD. The electronic databases MEDLINE, EMBASE, CINAHL, and Cochrane were searched for clinical trials which investigated outcomes of inflammatory cytokines and adipokines. Eligible studies included adults >18 y with NAFLD, which compared a dietary intervention with an alternative diet or control (no intervention) group or were accompanied by supplementation or other lifestyle interventions. Outcomes for inflammatory markers were grouped and pooled for meta-analysis where heterogeneity was allowed. Methodological quality and risk of bias were assessed using the Academy of Nutrition and Dietetics Criteria. Overall, 44 studies with a total of 2579 participants were included. Meta-analyses indicated intervention with an isocaloric diet plus supplement was more effective in reducing C-reactive protein (CRP) [standard mean difference (SMD): 0.44; 95% CI: 0.20, 0.68; P = 0.0003] and tumor necrosis factor-alpha (TNF-α) (SMD: 0.74; 95% CI: 0.02, 1.46; P = 0.03) than an isocaloric diet alone. No significant weighting was shown between a hypocaloric diet with or without supplementation for CRP (SMD: 0.30; 95% CI: -0.84, 1.44; P = 0.60) and TNF-α (SMD: 0.01; 95% CI: -0.43, 0.45; P = 0.97). In conclusion, hypocaloric and energy-restricted diets alone or with supplementation, and isocaloric diets with supplementation were shown to be most effective in improving the inflammatory profile of patients with NAFLD. To better determine the effectiveness of dietary intervention alone on a NAFLD population, further investigations of longer durations, with larger sample sizes are required.
-
2.
Polyphenol supplementation and executive functioning in overweight and obese adults at risk of cognitive impairment: A systematic review and meta-analysis.
Farag, S, Tsang, C, Murphy, PN
PloS one. 2023;18(5):e0286143
-
-
-
-
Free full text
Plain language summary
It is recognised that overweight and obesity pose an increased risk for the development of cardiometabolic disease, and increasing evidence indicates a link to cognitive impairment associated with early onset dementia in such populations. This study's aim was to elaborate on existing knowledge of the effectiveness or otherwise of polyphenols in general to improve executive function (EFs) in an obese/ overweight population at risk of cognitive impairment. This study was a systematic review and meta-analysis of twenty-three randomised controlled trials. Results showed a nonsignificant effect of polyphenols on EFs. Authors concluded that further research should consider investigating polyphenols supplementation in a younger population at risk of cognitive impairment.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Overweight and obesity have increasing evidence that indicates a link to compromised executive functions such as memory and decision-making processes and cognitive impairment
- This meta-analysis revealed a non-significant effect of polyphenol supplementation on executive functions among overweight and/or obese populations with a susceptibility to cognitive impairment.
Evidence Category:
-
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
-
X
B: Systematic reviews including RCTs of limited number
-
C: Non-randomized trials, observational studies, narrative reviews
-
D: Case-reports, evidence-based clinical findings
-
E: Opinion piece, other
Summary Review:
A systematic review and meta-analysis were undertaken to investigate the impact of polyphenol supplementation on executive functions (cognitive functions which constitute part of the working memory and decision-making processes) among overweight and/or obese populations.
Method:
A comprehensive literature search was conducted using four electronic databases: PubMed/Medline, PsycInfo, Scopus and the Cochrane Trials Library. Inclusion criteria encompassed primary research studies which investigated the impact of polyphenols versus placebo on executive function in overweight or obese adults.
The review comprised a total of 23 randomised controlled trials (RCTs), incorporating a participant pool of N = 1,976 individuals. The mean ages of participants in all 23 studies receiving polyphenol supplementation were 62.92 years (SD = 8.06 years) and the mean BMIs ranged from 25.5 kg/m2 to 33.7 kg/m2. Various dietary polyphenols were investigated in the studies, with the main groups being isoflavones, flavonoids, resveratrol, phenolic acid, curcumin, walnuts and blueberry powder.
- The JADAD scale was employed to assess the methodological quality of the incorporated studies
- Hedges g, accompanied by 95% confidence intervals (CI) for endpoints, was computed utilising a random effects model whenever applicable
- Various statistical methods were considered for potential application in evaluating publication bias
- Sensitivity analysis was conducted to assess the robustness of the obtained results.
Results
- Meta analysis of the 23 primary studies produced a non-significant effect of polyphenol supplementation on executive function (g = 0.076, CI = -0.018 to 0.170)
- A double-blind, randomised, placebo-controlled parallel study reported significant benefits in 60 participants (mean age 67 years) taking 80mg of curcumin over placebo for digital vigilance and serial subtraction tasks (p=0.041)
- A double-blind, randomised, placebo-controlled parallel intervention trial showed significant benefits in 79 patients (mean age of 61 years) taking 150mg of resveratrol for visuospatial working memory double span and trail making test (p= 0.012).
Conclusion:
This meta-analysis revealed a non-significant effect of polyphenol supplementation on executive functions among overweight and/or obese populations.
Clinical practice applications:
- Research has documented the association between compromised executive functions and obesity/overweight, emphasising neuroinflammation and oxidative stress as potential mechanisms
- A plausible intervention involves the utilisation of polyphenols, known for their antioxidant and anti-inflammatory properties
- This systematic review and meta-analysis revealed a non-significant effect of polyphenol supplementation on executive functions
- A potential beneficial impact for 80mg of curcumin and 150mg of resveratrol was revealed in younger populations (mean ages of 67 and 61 years).
Considerations for future research:
- A potential beneficial impact of 80mg of curcumin and 150mg of resveratrol supplementation was revealed in a younger population (mean ages of 67 and 61 years), highlighting the necessity for in-depth exploration in subsequent studies
- The diversity in tasks employed for assessing executive functions and the comprehensive reporting of the phenolic composition of supplements had limitations that warrant consideration in future research
- The exact constituent and dose of supplementation needs to be described as this is necessary for the identification of the potential beneficial compounds for cognitive health and to support clinical practice.
Abstract
BACKGROUND AND OBJECTIVES Increasing evidence indicates a link between obesity and cognitive impairment. Furthermore, there is limited literature regarding the effect of polyphenols, a plant derived compounds, on executive functioning in an overweight/obese population at-risk of cognitive impairment. The aim of the present systematic review and meta-analysis of randomized controlled trials is to examine the effect of polyphenol supplementation on executive functions in overweight and/or obese populations at risk of cognitive impairment. METHODS A comprehensive literature search was conducted from inception to March 2023 using four electronic databases: PubMed/Medline, PsycInfo, Scopus and Cochrane trials library. Published primary research studies in English that compared the effect of polyphenols with placebo on executive function in overweight/obese adults were considered eligible for the meta-analysis. Jadad scale was used for the methodological quality rating of the included studies. Hedges g with 95% confidence intervals (CI) for endpoints were calculated using random effect model where applicable. Rosenthal's Fail-safe N, funnel plots, the Begg and Mazumdar's rank correlation test (Kendall's S statistic P-Q), Egger's linear regression test, and Duval and Tweedie's trim-and-fill test were identified for potential use as appropriate, to examine publication bias. Sensitivity analysis was conducted to examine the robustness of the results. RESULTS AND CONCLUSION A total of 23 RCT studies involving N = 1,976 participants were included in the review. The results of the meta-analysis revealed a non-significant effect for polyphenol supplementation on executive function (g = 0.076, CI = -0.018 to 0.170). Observations from primary studies within the meta-analysis showed a potential positive effect of polyphenol supplementation in a younger population at-risk of cognitive impairment and it is recommended to investigate this further in future studies. Moreover, the variability of the tasks used to examine executive functions as well as the adequate reporting of supplement's phenolic composition is a limitation that future work should also consider.
-
3.
Treating asthma patients with probiotics: a systematic review and meta-analysis.
Xie, Q, Yuan, J, Wang, Y
Nutricion hospitalaria. 2023;40(4):829-838
-
-
-
Free full text
Plain language summary
Asthma is a common chronic inflammatory respiratory disease, with high morbidity and mortality. Recently, the efficacy of probiotics in allergic diseases has received special attention. Experiments have shown that probiotics have a clear effect on allergic diseases. The aim of this study was to study the efficacy of probiotics in the treatment of asthma and evaluate it, so as to provide a reference for the selection of treatment options for asthma patients. This study was a systematic review and meta-analysis of ten randomised controlled trials. Results showed that probiotics can improve symptoms and airway inflammation in patients with asthma, reduce acute exacerbation of asthma, and have no significant improvement in lung function. Authors concluded that the use of probiotics in patients with asthma can improve lung inflammation and asthma symptoms, as well as reduce the number of asthma attacks.
Abstract
Objective: To evaluate the role of probiotics in the treatment of asthma patients by meta-analysis. Methods: PubMed, Embase, The Cochrane Library, Web of Science, and other databases were searched by computer, and the relevant literature on the treatment of asthma by probiotics that met the inclusion criteria was screened by manual retrieval. Meta-analysis was performed using Revman 5.4 software and the combined effect was evaluated by odds ratio (OR) or mean difference (MD) and 95 % confidence interval (CI). Results: a total of ten references were included, all of which were randomized controlled studies, and a total of 1,101 people were investigated. Fractional exhaled nitric oxide (FeNO) (MD = -7.17, 95 % CI: -12.81, -1.54), asthma symptom severity (MD = -0.07, 95 % CI: -0.10, -0.04), Childhood Asthma Control Test (CACT) (MD = 2.26, 95 % CI: 1.14, 3.39), and the number of acute episodes of asthma (OR = 0.30, 95 % CI: 0.19, 0.47) in the probiotics group were better than those in the control group. There was no significant difference in forced expiratory volume in the first second (FEV1) (MD = 0.11, 95 % CI: -0.05, 0.26) and FEV1/FVC (%) (MD = 0.32, 95 % CI: -1.48, 2.12). Conclusion: the use of probiotics in patients with asthma can improve lung inflammation and asthma symptoms, reduce the number of asthma attacks, and have no effect on lung function. Objetivo: evaluar el papel de los probióticos en el tratamiento de pacientes con asma mediante metaanálisis. Métodos: se realizaron búsquedas informáticas en PubMed, Embase, The Cochrane Library, Web of Science y otras bases de datos, y se examinó la literatura relevante sobre el tratamiento del asma con probióticos que cumplía con los criterios de inclusión mediante recuperación manual. El metaanálisis se realizó con el software Revman 5.4 y el efecto combinado se evaluó mediante la razón de probabilidades (OR) o diferencia media (MD) y el intervalo de confianza (IC) del 95 %. Resultados: se incluyó un total de diez referencias, todas ellas estudios controlados aleatorios, y se investigó un total de 1.101 personas. El óxido nítrico exhalado (FeNO) (MD = -7,17, IC 95 %: -12,81, -1,54), la gravedad de los síntomas del asma (MD = -0,07, IC 95 %: -0,10, -0,04), la Prueba de Control del Asma (CACT-ACT) (MD = 2,26, IC 95 %: 1,14, 3,39) y el número de episodios agudos de asma (OR = 0,30, IC 95 %: 0,19, 0,47) en el grupo de probióticos fueron mejores que en el grupo de control. No hubo diferencia significativa en volumen espiratorio forzado en el primer segundo (FEV1) (DM = 0,11, IC 95 %: -0,05, 0,26) y FEV1/FVC (%) (DM = 0,32, IC 95 %: -1,48, 2,12). Conclusión: el uso de probióticos en pacientes con asma puede mejorar la inflamación pulmonar y los síntomas del asma, reducir el número de ataques de asma y no tener efecto sobre la función pulmonar.
-
4.
Effects of whey and soy protein supplementation on inflammatory cytokines in older adults: a systematic review and meta-analysis.
Prokopidis, K, Mazidi, M, Sankaranarayanan, R, Tajik, B, McArdle, A, Isanejad, M
The British journal of nutrition. 2023;129(5):759-770
-
-
-
-
Free full text
-
Plain language summary
Reduced muscle mass and reduction in physical activity may lead to sarcopenia in older people. Age-related sarcopenia is associated with increased systemic low-grade inflammation and obesity. Protein supplementation is found to be beneficial in reducing circulating pro-inflammatory cytokines in old people. Previous research has shown that supplementation with isolated whey and soy protein reduces the levels of inflammatory cytokines in older adults. However, there is limited research on intact whey and soy protein supplementation in reducing age-related inflammation. This systematic review and meta-analysis investigated the effect of intact whey and soy protein on serum inflammatory markers such as C-reactive protein (CRP), Interleukin-6 (IL6) and TNF-α in older adults. The results of this meta-analysis show a significant reduction in circulating IL-6 and TNF-α levels after the supplementation with whey and soy protein. The addition of soy isoflavones resulted in a further decline in serum CRP levels. Subgroup analysis showed that the whey protein supplementation significantly improved sarcopenia and pre-frailty. Healthcare professionals can use the result of this systematic review and meta-analysis to understand the anti-inflammatory properties of intact whey and soy protein and soy isoflavones. However, further robust studies are required to assess the anti-inflammatory properties of whey and soy protein due to the high heterogeneity of included studies in this review.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Nutritional strategies such as whey and soy protein supplementation may be regarded as safe and effective to attenuate adverse changes in muscle mass with ageing, however need to be considered alongside individual dietary intake and health status.
- Consider optimising protein intake and quality of protein through diet as an alternative or first line strategy.
Evidence Category:
-
X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
-
B: Systematic reviews including RCTs of limited number
-
C: Non-randomized trials, observational studies, narrative reviews
-
D: Case-reports, evidence-based clinical findings
-
E: Opinion piece, other
Summary Review:
Introduction
- A decline in muscle mass and physical capacity, known as sarcopenia, may start in the fourth decade with accumulation of adiposity, resulting in elevated circulating proinflammatory cytokines.
- Systematic and local elevation of oxidative stress and reactive oxygen species accumulation may accelerate age-related muscle wasting, however may be mitigated with antioxidant nutrients.
- This SR and MA evaluated whey and soy proteins effects on interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-α) and C-reactive protein (CRP) in older adults.
Methods
SR followed PRISMA guidelines, was registered on PROSPERO and included 31 RCT studies published in English between 2004-21. Intervention group received soy/whey supplements and comparator group received a placebo; circulating levels of CRP, IL-6 and/or TNF-α were assessed. MA used random-effects to calculate the pooled effects. Overall quality of evidence was rated as moderate.
Results
Males and females with a mean age 50 - 80 years were included.
Whey protein:
- IL-6 levels were reduced significantly (Number of studies (k) = 12, Mean Difference (MD): −0·79, 95 % Confidence Interval (CI): −1·15, −0·42, p< 0.01), however, high heterogeneity was observed (I2 = 96 %).
- Treatment duration ≤ 8 weeks showed a significant reduction in serum CRP (k = 4, MD: –0·30, 95 % CI: –0·39, –0·21, I2 = 0 %) compared with > 8 weeks (k = 6, MD: 0·13, 95 % CI: –0·13, 0·40, I2 = 9 %), whereas TNF-α and IL-6 remained unaltered.
- Individuals with sarcopenia and pre-frailty displayed a significant reduction of IL-6 (k = 3, MD: –0·98, 95 % CI: –1·56, –0·39, I2 = 0 %) but no benefits were observed for CRP or TNF.
Soy protein:
- There was a significant reduction in TNF-α (k = 6, MD: −0·16, 95 % CI: −0·26, p<0·05).
- The addition of isoflavones demonstrated a significant decrease in TNF-α (k = 5, MD: –0·20, 95 % CI: –0·31, –0·08, I2 = 34 %) but an increase in CRP (k = 7, MD: 0·53, 95 % CI: 0·12, 0·94), however high heterogeneity was observed in the latter (I2 = 91 %).
Conclusion
- The study found a significant reduction in IL-6 following whey protein with effects augmented in those with frailty and sarcopenia and a significant reduction in TNF-α following soy protein with effects augmented by additional soy isoflavones, possibly due to antioxidant effects.
Clinical practice applications:
- Consider whey and/or soy protein supplementation in older adults particularly those reported with pre-frailty and sarcopenia as an effective and safe strategy to attenuate low-grade inflammation and associated risks.
- Soy isoflavones may have additional antioxidant benefits for older adults although further research is needed to confirm this due to high heterogeneity found.
Considerations for future research:
Future research could:
- Evaluate other factors which influence the inflammatory profile such as nutrient density, vitamins and minerals supplementation and exercise.
- Include those with co-morbidities and healthy populations with placebo comparator groups.
- Evaluate dose and type of soy isoflavones on circulating inflammatory markers and the effect of combined whey and soy protein.
Abstract
BACKGROUND AND AIMS Low-grade inflammation is a mediator of muscle proteostasis. This study aimed to investigate the effects of isolated whey and soy proteins on inflammatory markers. METHODS We conducted a systematic literature search of randomised controlled trials (RCT) through MEDLINE, Web of Science, Scopus and Cochrane Library databases from inception until September 2021. To determine the effectiveness of isolated proteins on circulating levels of C-reactive protein (CRP), IL-6 and TNF-α, a meta-analysis using a random-effects model was used to calculate the pooled effects (CRD42021252603). RESULTS Thirty-one RCT met the inclusion criteria and were included in the systematic review and meta-analysis. A significant reduction of circulating IL-6 levels following whey protein [Mean Difference (MD): -0·79, 95 % CI: -1·15, -0·42, I2 = 96 %] and TNF-α levels following soy protein supplementation (MD: -0·16, 95 % CI: -0·26, -0·05, I2 = 68 %) was observed. The addition of soy isoflavones exerted a further decline in circulating TNF-α levels (MD: -0·20, 95 % CI: -0·31, -0·08, I2 = 34 %). According to subgroup analysis, whey protein led to a statistically significant decrease in circulating IL-6 levels in individuals with sarcopenia and pre-frailty (MD: -0·98, 95 % CI: -1·56, -0·39, I2 = 0 %). These findings may be dependent on participant characteristics and treatment duration. CONCLUSIONS These data support that whey and soy protein supplementation elicit anti-inflammatory effects by reducing circulating IL-6 and TNF-α levels, respectively. This effect may be enhanced by soy isoflavones and may be more prominent in individuals with sarcopenia.
-
5.
Absence of Effects of L-Arginine and L-Citrulline on Inflammatory Biomarkers and Oxidative Stress in Response to Physical Exercise: A Systematic Review with Meta-Analysis.
Porto, AA, Gonzaga, LA, Benjamim, CJR, Valenti, VE
Nutrients. 2023;15(8)
-
-
-
Free full text
Plain language summary
L-citrulline is a non-essential amino acid that acts as a precursor to L-arginine. L-arginine is a semi-essential amino acid used for nitric oxide production which is crucial for maintaining physiological function and immune regulation. Previous research has shown that L-citrulline and L-arginine supplementation may offer antioxidant and anti-inflammatory benefits in reducing exercise-related oxidative stress and inflammation. This systematic review and meta-analysis included seven randomised controlled trials to investigate the effect of L-citrulline and L-arginine on antioxidants, oxidative stress, and inflammatory and anti-inflammatory markers. This systematic review and meta-analysis showed no significant improvements in oxidative stress and inflammation followed by the supplementation of L-citrulline and L-arginine before exercise. However, further robust studies that include different dosages and exercise intensities are required to assess the beneficial effects of L-citrulline and L-arginine supplements to support physical exercise-induced oxidative stress and inflammation due to the heterogeneity of the included studies. Healthcare professionals can use the results of this study to understand the potential benefits of L-citrulline and L-arginine supplementation in people prone to producing proinflammatory cytokines.
Abstract
The repercussions on oxidative and inflammatory stress markers under the effects of arginine and citrulline in response to exercise are not fully reached. We completed a systematic review to investigate the effects of L-Citrulline or L-Arginine on oxidative stress and inflammatory biomarkers following exercise. EMBASE, MEDLINE (PubMed), Cochrane Library, CINAHL, LILACS, and Web of Science databases were used to record the trials. This study includes randomized controlled trials (RCTs) and non-RCTs with subjects over 18 years old. Those under the intervention protocol consumed L-Citrulline or L-Arginine, and the controls ingested placebo. We recognized 1080 studies, but only 7 were included (7 studies in meta-analysis). We observed no difference between pre- vs. post-exercise for oxidative stress (subtotal = -0.21 [CI: -0.56, 0.14], p = 0.24, and heterogeneity = 0%. In the sub-group "L-Arginine" we found a subtotal = -0.29 [-0.71, 0.12], p = 0.16, and heterogeneity = 0%. For the "L-Citrulline" subgroup we observed a subtotal = 0.00 [-0.67, 0.67], p = 1.00, and heterogeneity was not applicable. No differences were observed between groups (p = 0.47), and I² = 0%) or in antioxidant activity (subtotal = -0.28 [-1.65, 1.08], p = 0.68, and heterogeneity = 0%). In the "L-Arginine" sub-group, we found a subtotal = -3.90 [-14.18, 6.38], p = 0.46, and heterogeneity was not applicable. For the "L-Citrulline" subgroup, we reported a subtotal = -0.22 [-1.60, 1.16], p = 0.75, and heterogeneity was not applicable. No differences were observed between groups (p = 0.49), and I² = 0%), inflammatory markers (subtotal = 8.38 [-0.02, 16.78], p = 0.05, and heterogeneity = 93%. Tests for subgroup differences were not applicable, and anti-inflammatory markers (subtotal = -0.38 [-1.15, 0.39], p = 0.34 and heterogeneity = 15%; testing for subgroup differences was not applicable). In conclusion, our systematic review and meta-analysis found that L-Citrulline and L-Arginine did not influence inflammatory biomarkers and oxidative stress after exercise.
-
6.
Meta-Analysis Reveals Compositional and Functional Microbial Changes Associated with Osteoporosis.
Akinsuyi, OS, Roesch, LFW
Microbiology spectrum. 2023;11(3):e0032223
-
-
-
Free full text
Plain language summary
Osteoporosis (OP) is the most common metabolic bone disease associated with aging. Microbiome dysbiosis leading to impaired intestinal immune responses and subsequent production of osteoclastogenic cytokines has been proposed as the mechanism by which gut microbes are associated with osteoporosis. The aim of this study was to identify gut bacteria consistently associated with osteoporosis across different cohorts. This study was a meta-analysis of five studies. Results showed that gut microbial dysbiosis in osteoporosis patients is associated with functional changes, which result in significant changes in metabolites that play a key role in bone metabolism. Authors concluded that their findings set the stage for future studies to provide more comprehensive knowledge on how dysbiosis in the gut microbiome contributes to osteoporosis.
Abstract
Over the past decade, the role of the gut microbiota in many disease states has gained a great deal of attention. Mounting evidence from case-control and observational studies has linked changes in the gut microbiota to the pathophysiology of osteoporosis (OP). Nonetheless, the results of these studies contain discrepancies, leaving the literature without a consensus on osteoporosis-associated microbial signatures. Here, we conducted a comprehensive meta-analysis combining and reexamining five publicly available 16S rRNA partial sequence data sets to identify gut bacteria consistently associated with osteoporosis across different cohorts. After adjusting for the batch effect associated with technical variation and heterogeneity of studies, we observed a significant shift in the microbiota composition in the osteoporosis group. An increase in the relative abundance of opportunistic pathogens Clostridium sensu stricto, Bacteroides, and Intestinibacter was observed in the OP group. Moreover, short-chain-fatty-acid (SCFA) producers, including members of the genera Collinsella, Megasphaera, Agathobaculum, Mediterraneibacter, Clostridium XIV, and Dorea, were depleted in the OP group relative to the healthy control (HC) group. Lactic acid-producing bacteria, including Limosilactobacillus, were significantly increased in the OP group. The random forest algorithm further confirmed that these bacteria differentiate the two groups. Furthermore, functional prediction revealed depletion of the SCFA biosynthesis pathway (glycolysis, tricarboxylic acid [TCA] cycle, and Wood-Ljungdahl pathway) and amino acid biosynthesis pathway (methionine, histidine, and arginine) in the OP group relative to the HC group. This study uncovered OP-associated compositional and functional microbial alterations, providing robust insight into OP pathogenesis and aiding the possible development of a therapeutic intervention to manage the disease. IMPORTANCE Osteoporosis is the most common metabolic bone disease associated with aging. Mounting evidence has linked changes in the gut microbiota to the pathophysiology of osteoporosis. However, which microbes are associated with dysbiosis and their impact on bone density and inflammation remain largely unknown due to inconsistent results in the literature. Here, we present a meta-analysis with a standard workflow, robust statistical approaches, and machine learning algorithms to identify notable microbial compositional changes influencing osteoporosis.
-
7.
Anti-inflammatory effects of resveratrol in patients with cardiovascular disease: A systematic review and meta-analysis of randomized controlled trials.
Teimouri, M, Homayouni-Tabrizi, M, Rajabian, A, Amiri, H, Hosseini, H
Complementary therapies in medicine. 2022;70:102863
-
-
-
Free full text
Plain language summary
Cardiovascular diseases (CVDs) include various heart or/and blood vessel disorders, such as cerebrovascular disease, congenital heart disease, and coronary artery disease. It is well shown that prolonged or chronic inflammation plays a key role in the pathogenesis of several disorders, especially CVDs. Resveratrol has recently been considered a choice for preventing and treating inflammatory conditions. The aim of this study was to evaluate the impact of resveratrol on serum/plasma concentration of specific inflammatory markers - tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and c-reactive protein (CRP) - in patients with CVDs. This study is a systematic review and meta-analysis of six randomised controlled studies with a total of 415 participants. Results show that resveratrol significantly decreases CRP and TNF-α concentration; however, it did not significantly affect the serum concentration of IL-6 in patients with CVDs. Authors conclude that there is a potential preventive effect of resveratrol supplementation on inflammatory conditions in CVD patients. However, larger randomised clinical trials are needed to further investigate and explore the effects of resveratrol supplementations.
Abstract
BACKGROUND Chronic inflammation is one of the most important factors involved in the development and progression of cardiovascular disease (CVDs). Accumulating evidence has described the effect of resveratrol, a natural polyphenolic compound, on biomarkers of inflammation among patients with CVDs; however, findings are controversial. Here we performed a systematic review and meta-analysis of randomized controlled trials to evaluate the effect of resveratrol supplements on TNF-α, IL-6, and CRP levels in CVDs patients. METHODS Online research was conducted in the following database: MEDLINE, EMBASE, Cochrane Library, Web of Science databases, and Scopus. This systematic review and meta-analysis were conducted to investigate the effects of resveratrol supplements on inflammatory biomarkers among patients with CVDs. The meta-analysis was performed using Comprehensive Meta-Analysis (CMA) V3 software. RESULTS Six RCTs met the inclusion criteria and were selected for the current meta-analysis. Our results demonstrated that resveratrol significantly decreases serum levels of CRP (MD = -0.63, 95 % CI: -0.1.13, -0.12; p = 0.01), and TNF-α (MD = -0.55, 95 % CI: -1.04, -0.06; p = 0.02), however, resveratrol had not significant effect on serum concentration of IL-6 (MD = -0.12, 95 % CI: -0.52, 0.27; p = 0.53), in patients with CVDs. CONCLUSION Our results suggest that resveratrol can be used as a potential treatment in patients with CVD by reducing inflammatory conditions.
-
8.
Impact of Replacement of Individual Dietary SFAs on Circulating Lipids and Other Biomarkers of Cardiometabolic Health: A Systematic Review and Meta-Analysis of Randomized Controlled Trials in Humans.
Sellem, L, Flourakis, M, Jackson, KG, Joris, PJ, Lumley, J, Lohner, S, Mensink, RP, Soedamah-Muthu, SS, Lovegrove, JA
Advances in nutrition (Bethesda, Md.). 2022;13(4):1200-1225
-
-
-
Free full text
-
Plain language summary
Cardiovascular disease is one of the leading causes of mortality worldwide, and metabolic disorders such as diabetes, hyperlipidaemia, and hypertension contribute to this risk. Cardiometabolic disease (CMD) can be reduced by reducing saturated fatty acids (SFAs) and replacing them with unsaturated fatty acids (UFAs). Dietary SFA's are classified as a whole group in general dietary guidelines. However, blood lipid levels and other biomarkers of CMD may be affected differently by individual dietary SFAs. In this systematic review and meta-analysis, 44 randomised controlled trials were included that investigated the effects of replacing SFAs with individual dietary SFAs or UFAs on markers of CMD. CMD markers like Total cholesterol (TC), LDL cholesterol, and apoB concentrations were significantly reduced by replacing 1.5%TE of palmitic acid with oleic acid or UFAs for 14 days. The research also showed associations between apoB and LDL-cholesterol and apoA-I and HDL-cholesterol concentrations. Dietary palmitic acid substituted with UFAs significantly reduced fasting LDL-cholesterol and total cholesterol. The majority of studies included in this study focused on dietary palmitic acid and not much on stearic acid, myristic acid, or lauric acid. Therefore, further robust studies are required to assess the effect of individual dietary SFAs on the markers of CMD, including markers of inflammation, hemostasis, glycemic control, or metabolic hormones. Healthcare professionals can use this study to understand the benefits of substituting SFAs with UFAs on CMD markers.
Abstract
Little is known of the impact of individual SFAs and their isoenergetic substitution with other SFAs or unsaturated fatty acids (UFAs) on the prevention of cardiometabolic disease (CMD). This systematic literature review assessed the impact of such dietary substitutions on a range of fasting CMD risk markers, including lipid profile, markers of glycemic control and inflammation, and metabolic hormone concentrations. Eligible randomized controlled trials (RCTs) investigated the effect of isoenergetic replacements of individual dietary SFAs for ≥14 d on ≥1 CMD risk markers in humans. Searches of the PubMed, Embase, Scopus, and Cochrane CENTRAL databases on 14 February, 2021 identified 44 RCTs conducted in participants with a mean ± SD age of 39.9 ± 15.2 y. Studies' risk of bias was assessed using the Cochrane Risk of Bias tool 2.0 for RCTs. Random-effect meta-analyses assessed the effect of ≥3 similar dietary substitutions on the same CMD risk marker. Other dietary interventions were described in qualitative syntheses. We observed reductions in LDL-cholesterol concentrations after the replacement of palmitic acid (16:0) with UFAs (-0.36 mmol/L; 95% CI: -0.50, -0.21 mmol/L; I2 = 96.0%, n = 18 RCTs) or oleic acid (18:1n-9) (-0.16 mmol/L; 95% CI: -0.28, -0.03 mmol/L; I2 = 89.6%, n = 9 RCTs), with a similar impact on total cholesterol and apoB concentrations. No effects on other CMD risk markers, including HDL-cholesterol, triacylglycerol, glucose, insulin, or C-reactive protein concentrations, were evident. Similarly, we found no evidence of a benefit from replacing dietary stearic acid (18:0) with UFAs on CMD risk markers (n = 4 RCTs). In conclusion, the impact of replacing dietary palmitic acid with UFAs on lipid biomarkers is aligned with current public health recommendations. However, owing to the high heterogeneity and limited studies, relations between all individual SFAs and biomarkers of cardiometabolic health need further confirmation from RCTs. This systematic review was registered at www.crd.york.ac.uk/prospero/ as CRD42020084241.
-
9.
Elucidation of Prebiotics, Probiotics, Postbiotics, and Target from Gut Microbiota to Alleviate Obesity via Network Pharmacology Study.
Oh, KK, Gupta, H, Min, BH, Ganesan, R, Sharma, SP, Won, SM, Jeong, JJ, Lee, SB, Cha, MG, Kwon, GH, et al
Cells. 2022;11(18)
-
-
-
Free full text
Plain language summary
The prevalence of obesity and associated comorbidities, such as diabetes, heart attack, hypertension, and cancer, is increasing worldwide. Microbes in the gut may play a significant role in the management of obesity by fermenting dietary fibres and producing metabolites such as short-chain fatty acids and flavonoids. In this meta-analysis, data were retrieved about gut microbial metabolites from the gutMGene database to evaluate the beneficial effects of prebiotics, probiotics, and postbiotics on key targets of obesity. Tryptophan was converted into beneficial metabolites such as indole by Escherichia coli, and isoflavones were converted into equol by Lactobacillus paracasei JS1. A positive effect may be exerted by these metabolites on the treatment of obesity. According to this meta-analysis, equol can reduce the levels of Interleukin-6, one of the inflammatory cytokines associated with obesity. Prebiotic isoflavone is fermented by probiotic Lactobacillus paracasei JS1 to produce equol, a postbiotic that inhibits the action of interleukin-6 and exerts a beneficial effect on obesity. In addition to understanding the relationship between prebiotics, probiotics, and postbiotics, healthcare professionals can use the results of this study to modulate the pathophysiology of obesity. It is necessary to conduct further rigorous research in order to evaluate the pharmacological value of the elements.
Abstract
The metabolites produced by the gut microbiota have been reported as crucial agents against obesity; however, their key targets have not been revealed completely in complex microbiome systems. Hence, the aim of this study was to decipher promising prebiotics, probiotics, postbiotics, and more importantly, key target(s) via a network pharmacology approach. First, we retrieved the metabolites related to gut microbes from the gutMGene database. Then, we performed a meta-analysis to identify metabolite-related targets via the similarity ensemble approach (SEA) and SwissTargetPrediction (STP), and obesity-related targets were identified by DisGeNET and OMIM databases. After selecting the overlapping targets, we adopted topological analysis to identify core targets against obesity. Furthermore, we employed the integrated networks to microbiota-substrate-metabolite-target (MSMT) via R Package. Finally, we performed a molecular docking test (MDT) to verify the binding affinity between metabolite(s) and target(s) with the Autodock 1.5.6 tool. Based on holistic viewpoints, we performed a filtering step to discover the core targets through topological analysis. Then, we implemented protein-protein interaction (PPI) networks with 342 overlapping target, another subnetwork was constructed with the top 30% degree centrality (DC), and the final core networks were obtained after screening the top 30% betweenness centrality (BC). The final core targets were IL6, AKT1, and ALB. We showed that the three core targets interacted with three other components via the MSMT network in alleviating obesity, i.e., four microbiota, two substrates, and six metabolites. The MDT confirmed that equol (postbiotics) converted from isoflavone (prebiotics) via Lactobacillus paracasei JS1 (probiotics) can bind the most stably on IL6 (target) compared with the other four metabolites (3-indolepropionic acid, trimethylamine oxide, butyrate, and acetate). In this study, we demonstrated that the promising substate (prebiotics), microbe (probiotics), metabolite (postbiotics), and target are suitable for obsesity treatment, providing a microbiome basis for further research.
-
10.
Efficacy and safety of dietary polyphenol supplementation in the treatment of non-alcoholic fatty liver disease: A systematic review and meta-analysis.
Yang, K, Chen, J, Zhang, T, Yuan, X, Ge, A, Wang, S, Xu, H, Zeng, L, Ge, J
Frontiers in immunology. 2022;13:949746
-
-
-
Free full text
Plain language summary
Non-alcoholic fatty liver disease (NAFLD) is characterised by fat accumulation in the liver that can result in liver damage. NAFLD affects approximately 25% of the global population. There is evidence that dietary polyphenols can improve metabolism and insulin resistance and reduce inflammation and oxidative stress, which are the mechanisms that lead to liver damage in NAFLD. This systematic review and meta-analysis aimed to assess the effectiveness of dietary polyphenols in the treatment of non-alcoholic fatty liver disease (NAFLD). Eight dietary polyphenols, such as curcumin, resveratrol, naringenin, anthocyanin, hesperidin, catechin, silymarin, and genistein, were evaluated for their efficacy and safety. The administration of 80-3,000 mg of Curcumin for an 8-12 week duration is effective and safe for reducing body mass index, aspartate aminotransferase (AST), alanine aminotransferase (ALT), triglycerides (TG), total cholesterol (TC), and insulin resistance (HOMA-IR). Compared with the placebo, Naringenin reduced the percentage of NAFLD grade, TG, TC, and low-density lipoprotein cholesterol and increased high-density lipoprotein cholesterol. Hesperidin may potentially decrease body mass index (BMI), AST, ALT, TG, TC, and HOMA-IR. Catechin is safe, and 500-1000 mg supplementation for 12 weeks may reduce BMI, HOMA-IR, and TG. NAFLD patients who received silymarin showed improvements in ALT and AST, as well as reductions in hepatic fat accumulation and liver stiffness. 94–2100 mg of Silymarin supplementation for 8–48 weeks may reduce liver enzyme levels. Researchers can use the results of this study to understand the clinical utility of different polyphenol supplements in the treatment of NAFLD. Because the current evidence is highly heterogeneous in nature and limited in scope, further robust research is required on various classes of polyphenols and their effectiveness in reducing the severity of NAFLD.
Abstract
Background: Dietary polyphenol treatment of non-alcoholic fatty liver disease (NAFLD) is a novel direction, and the existing clinical studies have little effective evidence for its therapeutic effect, and some studies have inconsistent results. The effectiveness of dietary polyphenols in the treatment of NAFLD is still controversial. The aim of this study was to evaluate the therapeutic efficacy of oral dietary polyphenols in patients with NAFLD. Methods: The literature (both Chinese and English) published before 30 April 2022 in PubMed, Cochrane, Medline, CNKI, and other databases on the treatment of NAFLD with dietary polyphenols was searched. Manual screening, quality assessment, and data extraction of search results were conducted strictly according to the inclusion and exclusion criteria. RevMan 5.3 software was used to perform the meta-analysis. Results: The RCTs included in this study involved dietary supplementation with eight polyphenols (curcumin, resveratrol, naringenin, anthocyanin, hesperidin, catechin, silymarin, and genistein) and 2,173 participants. This systematic review and meta-analysis found that 1) curcumin may decrease body mass index (BMI), Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), Triglycerides (TG) total cholesterol (TC), and Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) compared to placebo; and curcumin does not increase the occurrence of adverse events. 2) Although the meta-analysis results of all randomized controlled trials (RCTs) did not reveal significant positive changes, individual RCTs showed meaningful results. 3) Naringenin significantly decreased the percentage of NAFLD grade, TG, TC, and low-density lipoprotein cholesterol (LDL-C) and increased high-density lipoprotein cholesterol (HDL-C) but had no significant effect on AST and ALT, and it is a safe supplementation. 4) Only one team presents a protocol about anthocyanin (from Cornus mas L. fruit extract) in the treatment of NAFLD. 5) Hesperidin may decrease BMI, AST, ALT, TG, TC, HOMA-IR, and so on. 6) Catechin may decrease BMI, HOMA-IR, and TG level, and it was well tolerated by the patients. 7) Silymarin was effective in improving ALT and AST and reducing hepatic fat accumulation and liver stiffness in NAFLD patients. Conclusion: Based on current evidence, curcumin can reduce BMI, TG, TC, liver enzymes, and insulin resistance; catechin can reduce BMI, insulin resistance, and TG effectively; silymarin can reduce liver enzymes. For resveratrol, naringenin, anthocyanin, hesperidin, and catechin, more RCTs are needed to further evaluate their efficacy and safety.