Effects of synbiotics supplementation on anthropometric and lipid profile parameters: Finding from an umbrella meta-analysis

Efficacy of Probiotics in Overweight and Obesity Control: An Umbrella Review and Subgroup Meta-Analysis

Numerous primary and secondary studies have consistently demonstrated that probiotics, including lactobacillus and Bifidobacterium, possess a potential anti-obesity effect. However, it is worth noting that some studies have yielded contrasting results. Considering this, our study aims to present a comprehensive overview of published systematic reviews and meta-analyses, focusing on the efficacy and safety of probiotics in managing obesity. To achieve this objective, we conducted an umbrella review following the PRISMA protocol and Cochrane guidelines. We searched databases such as Embase, PubMed, Cochrane Library, and Google Scholar for relevant systematic reviews and meta-analyses published in English, without imposing any date restrictions. Our inclusion criteria encompassed studies evaluating the anti-obesity impact of probiotics, with a specific focus on changes in body mass index (BMI), fat mass percentage (FMP), body weight (BW), and body fat mass (BFM). These studies were meticulously reviewed by two independent reviewers. Our analysis included five systematic reviews and 18 meta-analyses that met the predefined inclusion and exclusion criteria. The meta-analyses revealed statistically significant reductions in the following parameters: BMI, a decrease of 0.30 kg/m2 (p < 0.00001, 95% CI - 0.36 to - 0.25); BFM, a reduction of 0.86 kg (p < 0.00001, 95% CI - 1.02 to - 0.71); BW, a decrease of 0.59 kg (p < 0.00001, 95% CI - 0.74 to - 0.44); and FMP, a substantial decline of 78% (p < 0.00001, 95% CI - 1.02 to - 0.54). In summary, our umbrella review suggests that existing evidence supports the potential benefits of probiotics in managing obesity and overweight. However, it is essential to acknowledge that the credibility of this evidence is somewhat limited due to the inclusion of studies with poor-quality designs and relatively small participant numbers. To establish the true efficacy of probiotics in obesity management, we recommend conducting robust studies involving larger participant cohorts.

Efficacy of resveratrol supplementation on lipid profile parameters: An umbrella of meta-analysis

Several studies have evaluated the effects of resveratrol supplementation on lipid profile parameters in humans and have demonstrated varying results. We systematically evaluated the literature and performed an umbrella meta-analysis of the effects of resveratrol supplementation on lipid profile. A comprehensive literature search was conducted in the following databases; PubMed, Embase, Scopus, and Web of Science for studies published up to November 2023. According to the standardized mean difference (SMD) analysis, resveratrol supplementation was effective in reducing serum triglyceride (TG) (SMD = -0.14 mg/dl, 95 % CI: -0.24, -0.03; p = 0.001), total cholesterol (TC) (SMD = -0.20, 95 % CI: -0.31, -0.08; p= 0.001), but not high-density lipoprotein cholesterol (HDL-c) (SMD = 0.00, 95 % CI: -0.04, 0.05; p =0.92), and low-density lipoprotein-cholesterol (LDL-c) (SMD = -0.16 mg/dl, 95 % CI: -0.40, 0.07; p =0.17). In the weighted mean difference analysis, resveratrol did not significantly decrease lipid profile parameters. Resveratrol supplementation reduces TC and TG (based on SMD analysis), but it does not significantly affect other indices. However, these significant decreases are not clinically important. Therefore, resveratrol only can be considered as an adjunctive therapeutic approach in managing dyslipidemia.

The effect of probiotics on gestational diabetes mellitus: an umbrella meta-analysis

BACKGROUND

Prior studies indicated the positive effects of probiotics on glycemic regulation in patients with gestational diabetes mellitus (GDM). Nonetheless, the results remain inconclusive. To address this, we conducted an umbrella meta-analysis to evaluate the impact of probiotics on glycemic indicators in GDM.

METHODS

A comprehensive search was conducted on the PubMed and Scopus databases to identify all relevant meta-analyses of randomized clinical trials published until July 2024. The outcomes included serum hemoglobin A1C (HbA1c), fasting blood insulin (FBI), fasting blood sugar (FBS), homeostatic model assessment for insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), homeostatic model assessment of beta cell function (HOMA-B), C-peptide, and oral glucose tolerance test (OGTT). Standardized mean difference (SMD) was used to test the effects.

RESULTS

In total, 27 studies, comprising 33,378 participants, were included in the analysis. Probiotics resulted in a significant decrease in FBS (SMD: -0.39, 95% CI: -0.56 to -0.23), especially when administered for ≤ 7 weeks. Significant reductions were also observed in FBI (SMD: -1.99, 95% CI: -2.41 to -1.58), HOMA-IR (SMD: -0.61, 95% CI: -0.72 to -0.50), and HOMA-B (SMD: -24.58, 95% CI: -30.59 to -18.56). Moreover, supplementation with probiotics significantly improved QUICKI (SMD: 0.007, 95% CI: 0.004 to 0.01). There was significant evidence of heterogeneity and publication bias. No significant effects were observed on 1-h OGTT, 2-h OGTT, HbA1c, and C-peptide. No dose-specific effect was observed.

CONCLUSIONS

Supplementation with probiotics could improve glycemic control in women with GDM. The effects of probiotics on HOMA-IR, HOMA-B, and fasting insulin were clinically important, while, their effect on FBS was not clinically important.

Effectiveness of Probiotics, Prebiotics, and Synbiotics in Managing Insulin Resistance and Hormonal Imbalance in Women with Polycystic Ovary Syndrome (PCOS): A Systematic Review of Randomized Clinical Trials

Background/Objectives: Polycystic ovary syndrome is a common endocrine disorder in women of reproductive age characterized by insulin resistance and hormonal imbalances. Recent research suggests that probiotics and synbiotics may improve these parameters by modulating the gut microbiota. This study systematically reviewed randomized clinical trials evaluating the impact of probiotic, prebiotic, and synbiotic supplementation on insulin resistance and hormonal parameters in women with PCOS. Methods: Exhaustive searches were conducted in PubMed, Cochrane CENTRAL, Scopus, Web of Science, and Embase, following PRISMA guidelines. Randomized trials assessing supplementation with probiotics, prebiotics, or synbiotics for at least 8 weeks in women diagnosed with PCOS according to the Rotterdam criteria were included. Data on participants, interventions, and outcomes related to insulin resistance and hormones were extracted. Results: Eleven studies from Iran involving overweight or obese women aged 15 to 48 were included. Probiotic and synbiotic supplementation showed significant improvements in insulin resistance (reductions in HOMA-IR, fasting glucose, and insulin), lipid profiles (decreased LDL and triglycerides; increased HDL), and hormonal balance (increased SHBG, decreased total testosterone). Synbiotics had more pronounced effects than probiotics or prebiotics alone. Adherence was high, and side effects were minimal. Conclusions: Despite promising results, limitations such as small sample sizes, homogeneous populations, and short intervention durations limit the generalization of the findings. Larger, longer, multicenter trials with diverse populations and standardized methodologies are needed to confirm the efficacy and safety of synbiotics in managing PCOS. Integrating these interventions could improve clinical management and quality of life for affected women, but additional evidence is required to support widespread use.

Efficacy of probiotics, prebiotics, and synbiotics on liver enzymes, lipid profiles, and inflammation in patients with non-alcoholic fatty liver disease: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

There is a contradiction in the use of microbiota-therapies, including probiotics, prebiotics, and synbiotics, to improve the condition of patients with nonalcoholic fatty liver disease (NAFLD). The aim of this review was to evaluate the effect of microbiota-therapy on liver injury, inflammation, and lipid levels in individuals with NAFLD.

METHODS

Using Pubmed, Embase, Cochrane Library, and Web of Science databases were searched for articles on the use of prebiotic, probiotic, or synbiotic for the treatment of patients with NAFLD up to March 2024.

RESULTS

Thirty-four studies involving 12,682 individuals were included. Meta-analysis indicated that probiotic, prebiotic, and synbiotic supplementation significantly improved liver injury (hepatic fibrosis, SMD = -0.31; 95% CI: -0.53, -0.09; aspartate aminotransferase, SMD = -0.35; 95% CI: -0.55, -0.15; alanine aminotransferase, SMD = -0.48; 95% CI: -0.71, -0.25; alkaline phosphatase, SMD = -0.81; 95% CI: -1.55, -0.08), lipid profiles (triglycerides, SMD = -0.22; 95% CI: -0.43, -0.02), and inflammatory factors (high-density lipoprotein, SMD = -0.47; 95% CI: -0.88, -0.06; tumour necrosis factor alpha, SMD = -0.86 95% CI: -1.56, -0.56).

CONCLUSION

Overall, supplementation with probiotic, prebiotic, or synbiotic had a positive effect on reducing liver enzymes, lipid profiles, and inflammatory cytokines in patients with NAFLD.

Garlic consumption can reduce the risk of dyslipidemia: a meta-analysis of randomized controlled trials

BACKGROUND AND PURPOSE

Garlic is used as an important medicinal food for treatment of many diseases, however, the association between garlic consumption and dyslipidemia have yielded inconsistent results. So we carried this meta-analysis to explore the blood lipid-lowering effects of garlic.

METHODS

Databases such as PubMed, Scopus, Web of science, Embase, Cochrane Library were systematically searched until June 2024. Heterogeneity among studies was examined using Q and I2 statistics. Also subgroup analysis were conducted to explore the potential heterogeneity. Combined weighted mean differences (WMD) with their 95% confidence interval (CI) were calculated using a random-effects model. The GRADE approach was used to evaluate the overall certainty of the evidence in the meta-analyses.

RESULTS

A total of 21 RCTs studies involved association between garlic consumption and blood lipids level of dyslipidemia patients were included in the meta-analysis. The pooled results showed that garlic consumption significantly reduced total cholesterol (TC)(WMD = -0.64mmol/L, 95%CI = -0.75 --0.54, P < 0.001), triglyceride (TG)(WMD = -0.17mmol/L, 95%CI = -0.26 --0.09, P < 0.001), low-density lipoprotein(LDL-C)(WMD = -0.44mmol/L, 95%CI = -0.57 --0.31, P < 0.001) while slightly increased high-density lipoprotein (HDL-C)(WMD = 0.04mmol/L, 95%CI = -0.00 - 0.08, P < 0.001). And subgroup analyses showed that TC, TG and LDL-C significantly decreased in patients aged > 50 years compared to those aged ≤ 50 years. And garlic oil greatly reduced TC and LDL-C compared with garlic power. Finally, sensitivity analysis and publication bias showed that the results were reliable.

CONCLUSIONS

Evidence from this meta-analysis suggested that garlic consumption could be effective in reducing the risk of dyslipidemia and preventing CVDs. Particularly the older people were more susceptible to the protective effects of garlic.

Effects of mind-body interventions on polycystic ovary syndrome: a comprehensive meta-analysis

BACKGROUND

Mind-body interventions (MBI) have emerged as a potential therapeutic approach, but their effectiveness in the treatment of Polycystic Ovary Syndrome (PCOS) remains inconclusive. This study systematically evaluates the effectiveness of MBI on quality of life, anthropometry, androgen secretion, glucose, and lipid metabolism in PCOS.

METHODS

A computer search was conducted across three databases: PubMed, the Cochrane Library, and EMBASE, to identify randomized controlled trials (RCTs) related to MBI for PCOS from their inception until July 2024. DerSimonian and Laird's random-effects model and Stata 17.0 software was employed for our meta-analysis.

RESULTS

Twelve RCTs were included. MBI significantly improved PCOSQ subscale scores, including emotional disturbances (MD: 7.75, 95% CI: 6.10 to 9.40), body hair (MD: 2.73, 95% CI: 0.54 to 4.91), menstrual problems (MD: 3.79, 95% CI: 2.89 to 4.69), and weight (MD: 1.48, 95% CI: 0.03 to 2.93). Furthermore, there was a reduction in depression levels (MD: -1.53, 95% CI: -2.93 to -0.13). Sensitivity analysis confirmed the robustness of PCOSQ-Emotional disturbances and PCOSQ-Menstrual problems, with a high GRADE level of evidence for these subscales. Secondary outcome measures, including waist-hip ratio, fasting blood glucose, and HOMA-IR exhibited statistically significant differences. Subgroup analysis revealed that obesity could influence treatment outcomes.

CONCLUSION

MBI can serve as an alternative therapy, modulating effect on the quality of life and depression in PCOS patients. Future well-designed, high-quality, and large-scale studies should be conducted to thoroughly assess the impact of different Mind-Body Interventions (MBI) on various PCOS phenotypes.

TRIAL REGISTRATION

PROSPERO (CRD42023472035).

The effects of prebiotic, probiotic or synbiotic supplementation on overweight/obesity indicators: an umbrella review of the trials' meta-analyses

Background

There is controversial data on the effects of prebiotic, probiotic, or synbiotic supplementations on overweight/obesity indicators. Thus, we aimed to clarify this role of biotics through an umbrella review of the trials' meta-analyses.

Methods

All meta-analyses of the clinical trials conducted on the impact of biotics on overweight/obesity indicators in general populations, pregnant women, and infants published until June 2023 in PubMed, Web of Sciences, Scopus, Embase, and Cochrane Library web databases included. The meta-analysis of observational and systematic review studies without meta-analysis were excluded. We reported the results by implementing the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) flowchart. The Assessment of Multiple Systematic Reviews-2 (AMSTAR2) and Grading of Recommendations Assessment, Development, and Evaluation (GRADE) systems were used to assess the methodological quality and quality of evidence.

Results

Overall, 97 meta-analysis studies were included. Most studies were conducted on the effect of probiotics in both genders. Consumption of prebiotic: 8-66 g/day, probiotic: 104 -1.35×1015 colony-forming unit (CFU)/day, and synbiotic: 106-1.5×1011 CFU/day and 0.5-300 g/day for 2 to 104 weeks showed a favorable effect on the overweight/obesity indicators. Moreover, an inverse association was observed between biotics consumption and overweight/obesity risk in adults in most of the studies. Biotics did not show any beneficial effect on weight and body mass index (BMI) in pregnant women by 6.6×105-1010 CFU/day of probiotics during 1-25 weeks and 1×109-112.5×109 CFU/capsule of synbiotics during 4-8 weeks. The effect of biotics on weight and BMI in infants is predominantly non-significant. Prebiotics and probiotics used in infancy were from 0.15 to 0.8 g/dL and 2×106-6×109 CFU/day for 2-24 weeks, respectively.

Conclusion

It seems biotics consumption can result in favorable impacts on some anthropometric indices of overweight/obesity (body weight, BMI, waist circumference) in the general population, without any significant effects on birth weight or weight gain during pregnancy and infancy. So, it is recommended to intake the biotics as complementary medications for reducing anthropometric indices of overweight/obese adults. However, more well-designed trials are needed to elucidate the anti-obesity effects of specific strains of probiotics.

Effect of Continuous Ingestion of Bifidobacteria and Inulin on Reducing Body Fat: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Comparison Study

Bifidobacterium animalis subsp. lactis GCL2505 has been shown to have several positive health effects, including improved defecation frequency and reduced visceral fat. It is known that combined intake of GCL2505 and inulin increases the total number of bifidobacteria compared with ingestion of GCL2505 alone. This randomized, double-blind, placebo-controlled, parallel-group study was conducted to confirm that consumption of GCL2505 and inulin reduces abdominal fat (n = 120). Participants consumed a test beverage containing 1 × 1010 colony-forming units of GCL2505 per 100 g and 2.0 g of inulin per 100 g for 12 weeks. A change in the visceral fat area (VFA) was set as the primary endpoint. There were significant reductions in VFA and total fat area. The intervention significantly increased the total number of bifidobacteria and affected the levels of several lipid markers. Regression analysis of bifidobacteria and measured parameters showed that total bifidobacteria correlated with VFA and body mass index (BMI), while endogenous bifidobacteria and Bifidobacterium animalis subsp. lactis correlated only with BMI, suggesting that increases in both contributed to the decrease in VFA. These results suggest that combined intake of GCL2505 and inulin improves the intestinal environment and reduces abdominal fat in association with the SCFA-mediated pathway.

Dietary fats and serum lipids in relation to the risk of ovarian cancer: a meta-analysis of observational studies

Although numerous epidemiological studies investigated the association between dietary fat intakes or serum lipid levels and ovarian cancer risk, a consistent and explicit conclusion for specific dietary fats or serum lipids that increase the risk of ovarian cancer is not available. In this study, a systematic review and meta-analysis were conducted to assess the key dietary fats and serum lipids that increased the risk of ovarian cancer. Databases such as PubMed, Web of Science, and EMBASE were searched for observational studies. A total of 41 studies met the inclusion criteria, including 18 cohort and 23 case-control studies (109,507 patients with ovarian cancer and 2,558,182 control/non-ovarian cancer participants). Higher dietary intakes of total fat (RR = 1.19, 95% CI = 1.06-1.33, I2 = 60.3%), cholesterol (RR = 1.14, 95% CI = 1.03-1.26, I2 = 19.4%), saturated fat (RR = 1.13, 95% CI = 1.04-1.22, I2 = 13.4%), and animal fat (RR = 1.21, 95% CI = 1.01-1.43, I2 = 70.5%) were significantly associated with a higher risk of ovarian cancer. A higher level of serum triglycerides was accompanied by a higher risk of ovarian cancer (RR = 1.33, 95% CI = 1.02-1.72, I2 = 89.3%). This meta-analysis indicated that a higher daily intake of total fat, saturated fat, animal fat, and cholesterol and higher levels of serum triglycerides were significantly associated with an increased risk of ovarian cancer.