Efficacy of synbiotic supplementation in obesity treatment: A systematic review and meta-analysis of clinical trials

Impact of walnut consumption on glycemic control and anthropometric indices: a systematic review and meta-analysis of randomized controlled trials

Objectives

Previous studies have led to conflicting results regarding the effect of walnut consumption on glycemic control, and anthropometric indices. This study aimed to evaluate the efficacy of walnut consumption on serum levels of fasting blood sugar (FBS), fasting insulin, hemoglobin A1C (HbA1c), homeostasis model assessment of insulin resistance (HOMA-IR), weight and body mass index (BMI) through a systematic review and meta-analysis of randomized controlled trials (RCTs).

Methods

PubMed, Scopus, Web of Science, and the Cochrane databases were searched up to February 2023. Weighted mean difference (WMD) was analyzed using random effects models to assess the overall effect.

Results

A total of thirty-two RCTs were included in the systematic review and meta-analysis. Walnut supplementation was found to significantly reduce HOMA-IR (WMD = -0.29; 95% CI: -0.57, -0.01, P = 0.04), and body weight (WMD = -0.14 kg; 95% CI: -0.24, -0.04; P = 0.008). However, the meta-analysis showed that walnut supplementation did not have a significant effect on FBS (WMD = 0.62 mg/dL; 95% CI: -0.66, 1.91; P = 0.34), insulin levels (WMD = 1.27 mIU/ml; 95% CI: -0.59, 3.14; P = 0.18), HbA1C (WMD = 0.00%; 95% CI: -0.09, 0.10; P = 0.95), and BMI (WMD = -0.10 kg/m2; 95% CI: -0.40, 0.20; P = 0.50).

Conclusion

In conclusion, this study found a significant reduction in HOMA-IR levels and body weight with walnut supplementation, while other glycemic markers, and obesity-related indices did not change significantly. Future well-designed trials are needed to confirm these results.

Effects of synbiotics surpass probiotics alone in improving type 2 diabetes mellitus: A randomized, double-blind, placebo-controlled trial

BACKGROUND AND AIMS

Combining probiotics and prebiotics in synbiotics may present a synergistic approach to improve type 2 diabetes mellitus (T2DM); however, further evidence is required to establish the comparative efficacy of synbiotics versus probiotics. This study aimed to evaluate the effects of Bifidobacterium animalis subsp. lactis MN-Gup (MN-Gup) and a synbiotic mixture of MN-Gup and galactooligosaccharide (MN-Gup-GOS) on glycemic control in T2DM patients and explore possible mechanisms.

METHODS

This randomized, double-blind, placebo-controlled clinical trial assigned 120 T2DM patients, to receive MN-Gup, MN-Gup-GOS, or placebo intervention for 12 weeks. The primary outcome was fasting blood glucose (FBG), with secondary outcomes including hemoglobin A1C (HbA1C), insulin, homeostatic model assessment of insulin resistance (HOMA-IR), inflammatory indicators, oxidative stress indicators, gastrointestinal hormones, gut microbiota, and bile acids (BAs).

RESULTS

The median age of the 120 participants was 59 years (interquartile range: 55-62 years), with 40 being men. Compared to baseline, all three groups exhibited significant reductions in FBG. Additionally, the MN-Gup-GOS group demonstrated significant decreases in HbA1c, serum insulin, and HOMA-IR after intervention, whereas no such reductions were observed in the placebo and MN-Gup groups. Regarding the between-group comparisons, the MN-Gup-GOS intervention showed a significantly greater reduction in FBG compared to the placebo (least squares mean difference [95 % CI], -0.69 [-1.29, -0.10] mmol/L, P = 0.022) and MN-Gup (-0.59 [-1.17, -0.01], P = 0.047) group, but not for other indicators of glucose metabolism. Additionally, MN-Gup and MN-Gup-GOS intervention, especially the latter, significantly modified inflammation, oxidative stress, gut microbiota, serum BAs, and GLP-1 levels. Correlation analysis showed significant associations between changes in certain gut microbiota (Bifidobacterium) and BAs (deoxycholic acid and lithocholic acid) with glycemic indicators.

CONCLUSIONS

The auxiliary effect of synbiotics MN-Gup-GOS on reducing FBG levels surpassed that of MN-Gup probiotics alone in T2DM patients, potentially attributed to the enhanced modulation of gut microbiota, BAs, and GLP-1 secretion.

TRIAL REGISTRATION

This study was registered on the website of www.chictr.org.cn, number ChiCTR2100052187.

Health-Promoting and Functional Properties of Fermented Milk Beverages with Probiotic Bacteria in the Prevention of Civilization Diseases

BACKGROUND/OBJECTIVES

There is scattered information in the scientific literature regarding the characterization of probiotic bacteria found in fermented milk beverages and the beneficial effects of probiotic bacteria on human health. Our objective was to gather the available information on the use of probiotic bacteria in the prevention of civilization diseases, with a special focus on the prevention of obesity, diabetes, and cancer.

METHODS

We carried out a literature review including the following keywords, either individually or collectively: lactic acid bacteria; probiotic bacteria; obesity; lactose intolerance; diabetes; cancer protection; civilization diseases; intestinal microbiota; intestinal pathogens.

RESULTS

This review summarizes the current state of knowledge on the use of probiotic bacteria in the prevention of civilization diseases. Probiotic bacteria are a set of living microorganisms that, when administered in adequate amounts, exert a beneficial effect on the health of the host and allow for the renewal of the correct quantitative and qualitative composition of the microbiota. Probiotic bacteria favorably modify the composition of the intestinal microbiota, inhibit the development of intestinal pathogens, prevent constipation, strengthen the immune system, and reduce symptoms of lactose intolerance. As fermented milk beverages are an excellent source of probiotic bacteria, their regular consumption can be a strong point in the prevention of various types of civilization diseases.

CONCLUSIONS

The presence of lactic acid bacteria, including probiotic bacteria in fermented milk beverages, reduces the incidence of obesity and diabetes and serves as a tool in the prevention of cancer diseases.

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.

Understanding the role of the human gut microbiome in overweight and obesity

The gut microbiome may be related to the prevalence of overweight and obesity, but high interindividual variability of the human microbiome complicates our understanding. Obesity often occurs concomitantly with micronutrient deficiencies that impair energy metabolism. Microbiota composition is affected by diet. Host-microbiota interactions are bidirectional. We propose three pathways whereby these interactions may modulate the gut microbiome and obesity: (1) ingested compounds or derivatives affecting small intestinal transit, endogenous secretions, digestion, absorption, microbiome balance, and gut barrier function directly affect host metabolism; (2) substrate availability affecting colonic microbial composition and contact with the gut barrier; and (3) microbial end products affecting host metabolism. The quantity/concentration, duration, and/or frequency (circadian rhythm) of changes in these pathways can alter the gut microbiome, disrupt the gut barrier, alter host immunity, and increase the risk of and progression to overweight and obesity. Host-specific characteristics (e.g., genetic variations) may further affect individual sensitivity and/or resilience to diet- and microbiome-associated perturbations in the colonic environment. In this narrative review, the effects of selected interventions, including fecal microbiota transplantation, dietary calorie restriction, dietary fibers and prebiotics, probiotics and synbiotics, vitamins, minerals, and fatty acids, on the gut microbiome, body weight, and/or adiposity are summarized to help identify mechanisms of action and research opportunities.

Effects of probiotics, prebiotics, and synbiotics on cardiometabolic risk factors in children and adolescents with overweight or obesity: a systematic review and Bayesian network meta-analysis

The efficacy of probiotics, prebiotics, or synbiotics in children and adolescents with overweight or obesity remains uncertain. This systematic review evaluates their intervention effects through a network meta-analysis of randomized clinical trials (RCTs). Searches of 4 electronic databases until January 7, 2024, yielded 17 papers reporting on 15 RCTs involving 820 participants. Multiple-strain probiotics (MSP) showed significant efficacy in reducing BMI (Mean Difference (MD) -2.13 kg/m2, 95% credible interval (CrI) [-2.7, -1.57]), waist circumference (MD -1.34 cm, 95% CrI [-2.33, -0.35]), total cholesterol (MD -6.55 mg/dL, 95% CrI [-10.61, -2.45]), triglycerides (MD -3.71 mg/dL, 95% CrI [-5.76, -1.67]), leptin (MD -3.99 ng/mL, 95% CrI [-4.68, -3.3]), and hypersensitive C-reactive protein (Hs-CRP) (MD -1.21 mg/L, 95% CrI [-1.45, -0.97]). Synbiotics were effective in reducing BMI-z score (MD -0.07, 95% CrI [-0.10, -0.04]) and LDL-C (MD -1.54 mg/dL, 95% CrI [-1.98, -1.09]) but led to a slight increase in fasting glucose (MD 1.12 mg/dL, 95% CrI [0.75, 1.49]). Single-ingredient prebiotics and single-strain probiotics also had some beneficial effects on BMI and Hs-CRP, respectively. Moderate to low evidence suggests MSP may be a potential choice for improving BMI and reducing lipids, leptin, and Hs-CRP levels, implying that MSP could aid in managing pediatric obesity and related metabolic issues by modulating the gut microbiota. Although synbiotics show their favorable effects on body metrics and lipid control, their potential impact on blood glucose currently prevents them from being an alternative to MSP for treating pediatric obesity. Further large-scale, well-designed studies are needed to confirm these findings.

Use of probiotics in preventing and treating excess weight and obesity. A systematic review

Background

The prevalence of excess weight and obesity is increasing in an extremely concerning manner worldwide, with highly diverse therapies for current treatment. This review evaluated the scientific evidence of the past 10 years on the use of probiotics in treating excess weight and obesity in the absence of dieting.

Materials

A systematic review was conducted by searching for clinical trials on humans published in English in the PubMed, Scopus and Cochrane Central databases, using the combination of keywords "Overweight", "Probiotics" and "Obesity", and published between 2012 and 2022.

Results

Six published studies met the inclusion criteria. The review showed that, although there is a lack of consensus in the literature, the use of probiotics in the absence of dieting produced a significant reduction in body weight and body mass index in 66.6% of the reviewed studies, a significant reduction in waist circumference in 80.0% of the reviewed studies, and an improvement in total body fat mass and waist circumference.

Conclusions

This review showed evidence of a trend in preventing body weight gain and reducing weight through the use of probiotics in individuals with excess weight or obesity. A combination of various strains of the genera Bifidobacterium and Lactobacillus was the most effective.

Effects of dietary fibre on metabolic health and obesity

Obesity and metabolic syndrome represent a growing epidemic worldwide. Body weight is regulated through complex interactions between hormonal, neural and metabolic pathways and is influenced by numerous environmental factors. Imbalances between energy intake and expenditure can occur due to several factors, including alterations in eating behaviours, abnormal satiation and satiety, and low energy expenditure. The gut microbiota profoundly affects all aspects of energy homeostasis through diverse mechanisms involving effects on mucosal and systemic immune, hormonal and neural systems. The benefits of dietary fibre on metabolism and obesity have been demonstrated through mechanistic studies and clinical trials, but many questions remain as to how different fibres are best utilized in managing obesity. In this Review, we discuss the physiochemical properties of different fibres, current findings on how fibre and the gut microbiota interact to regulate body weight homeostasis, and knowledge gaps related to using dietary fibres as a complementary strategy. Precision medicine approaches that utilize baseline microbiota and clinical characteristics to predict individual responses to fibre supplementation represent a new paradigm with great potential to enhance weight management efficacy, but many challenges remain before these approaches can be fully implemented.

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.

Beneficial effects of the probiotics and synbiotics supplementation on anthropometric indices and body composition in adults: A systematic review and meta-analysis

Studies have suggested that probiotics and synbiotics can improve body weight and composition. However, randomized controlled trials (RCTs) demonstrated mixed results. Hence, we performed a systematic review and meta-analysis to evaluate the effectiveness of probiotics and synbiotics on body weight and composition in adults. We searched PubMed/Medline, Ovid/Medline, Scopus, ISI Web of Science, and Cochrane library up to April 2023 using related keywords. We included all RCTs investigating the effectiveness of probiotics and/or synbiotics supplementation on anthropometric indices and body composition among adults. Random-effects models were applied for performing meta-analyses. In addition, we conducted subgroup analyses and meta-regression to explore the non-linear and linear relationship between the length of follow-up and the changes in each outcome. We included a total of 200 trials with 12,603 participants in the present meta-analysis. Probiotics or synbiotics intake led to a significant decrease in body weight (weighted mean difference [WMD]: -0.91 kg; 95% CI: -1.08, -0.75; p < 0.001), body mass index (BMI) (WMD: -0.28 kg/m2 ; 95% CI: -0.36, -0.21; p < 0.001), waist circumference (WC) (WMD: -1.14 cm; 95% CI: -1.42, -0.87; p < 0.001), waist-to-hip ratio (WHR) (WMD: -0.01; 95% CI: -0.01, -0.00; p < 0.001), fat mass (FM) (WMD: -0.92 kg; 95% CI: -1.05, -0.79; p < 0.001), and percentage of body fat (%BF) (WMD: -0.68%; 95% CI: -0.94, -0.42; p < 0.001) compared to controls. There was no difference in fat-free mass (FFM) and lean body mass (LBM). Subgroup analyses indicated that probiotics or synbiotics administered as food or supplement resulted in significant changes in anthropometric indices and body composition. However, compared to controls, FM and %BF values were only reduced after probiotic consumption. Our results showed that probiotics or synbiotics have beneficial effects on body weight, central obesity, and body composition in adults and could be useful as an add on to weight loss products and medications.

Therapeutic applications of gut microbes in cardiometabolic diseases: current state and perspectives

Cardiometabolic disease (CMD) encompasses a range of diseases such as hypertension, atherosclerosis, heart failure, obesity, and type 2 diabetes. Recent findings about CMD's interaction with gut microbiota have broadened our understanding of how diet and nutrition drive microbes to influence CMD. However, the translation of basic research into the clinic has not been smooth, and dietary nutrition and probiotic supplementation have yet to show significant evidence of the therapeutic benefits of CMD. In addition, the published reviews do not suggest the core microbiota or metabolite classes that influence CMD, and systematically elucidate the causal relationship between host disease phenotypes-microbiome. The aim of this review is to highlight the complex interaction of the gut microbiota and their metabolites with CMD progression and to further centralize and conceptualize the mechanisms of action between microbial and host disease phenotypes. We also discuss the potential of targeting modulations of gut microbes and metabolites as new targets for prevention and treatment of CMD, including the use of emerging technologies such as fecal microbiota transplantation and nanomedicine. KEY POINTS: • To highlight the complex interaction of the gut microbiota and their metabolites with CMD progression and to further centralize and conceptualize the mechanisms of action between microbial and host disease phenotypes. • We also discuss the potential of targeting modulations of gut microbes and metabolites as new targets for prevention and treatment of CMD, including the use of emerging technologies such as FMT and nanomedicine. • Our study provides insight into identification-specific microbiomes and metabolites involved in CMD, and microbial-host changes and physiological factors as disease phenotypes develop, which will help to map the microbiome individually and capture pathogenic mechanisms as a whole.

Short-chain fatty acids and insulin sensitivity: a systematic review and meta-analysis

CONTEXT

There is substantial evidence that reduced short-chain fatty acids (SCFAs) in the gut are associated with obesity and type 2 diabetes, although findings from clinical interventions that can increase SCFAs are inconsistent.

OBJECTIVE

This systematic review and meta-analysis aimed to assess the effect of SCFA interventions on fasting glucose, fasting insulin, and homeostatic model assessment of insulin resistance (HOMA-IR).

DATA SOURCES

Relevant articles published up to July 28, 2022, were extracted from PubMed and Embase using the MeSH (Medical Subject Headings) terms of the defined keywords [(short-chain fatty acids) AND (obesity OR diabetes OR insulin sensitivity)] and their synonyms. Data analyses were performed independently by two researchers who used the Cochrane meta-analysis checklist and the PRISMA guidelines.

DATA EXTRACTION

Clinical studies and trials that measured SCFAs and reported glucose homeostasis parameters were included in the analysis. Standardized mean differences (SMDs) with 95%CIs were calculated using a random-effects model in the data extraction tool Review Manager version 5.4 (RevMan 5.4). The risk-of-bias assessment was performed following the Cochrane checklist for randomized and crossover studies.

DATA ANALYSIS

In total, 6040 nonduplicate studies were identified, 23 of which met the defined criteria, reported fasting insulin, fasting glucose, or HOMA-IR values, and reported change in SCFA concentrations post intervention. Meta-analyses of these studies indicated that fasting insulin concentrations were significantly reduced (overall effect: SMD = -0.15; 95%CI = -0.29 to -0.01, P = 0.04) in treatment groups, relative to placebo groups, at the end of the intervention. Studies with a confirmed increase in SCFAs at the end of intervention also had a significant effect on lowering fasting insulin (P = 0.008). Elevated levels of SCFAs, compared with baseline levels, were associated with beneficial effects on HOMA-IR (P < 0.00001). There was no significant change in fasting glucose concentrations.

CONCLUSION

Increased postintervention levels of SCFAs are associated with lower fasting insulin concentrations, offering a beneficial effect on insulin sensitivity.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42021257248.

Prebiotics, Probiotics, and Synbiotics-A Research Hotspot for Pediatric Obesity

Childhood obesity is a major public health problem worldwide with an increasing prevalence, associated not only with metabolic syndrome, insulin resistance, hypertension, dyslipidemia, and non-alcoholic fatty liver disease (NAFLD), but also with psychosocial problems. Gut microbiota is a new factor in childhood obesity, which can modulate the blood lipopolysaccharide levels, the satiety, and fat distribution, and can ensure additional calories to the host. The aim of this review was to assess the differences and the impact of the gut microbial composition on several obesity-related complications such as metabolic syndrome, NAFLD, or insulin resistance. Early dysbiosis was proven to be associated with an increased predisposition to obesity. Depending on the predominant species, the gut microbiota might have either a positive or negative impact on the development of obesity. Prebiotics, probiotics, and synbiotics were suggested to have a positive effect on improving the gut microbiota and reducing cardio-metabolic risk factors. The results of clinical trials regarding probiotic, prebiotic, and synbiotic administration in children with metabolic syndrome, NAFLD, and insulin resistance are controversial. Some of them (Lactobacillus rhamnosus bv-77, Lactobacillus salivarius, and Bifidobacterium animalis) were proven to reduce the body mass index in obese children, and also improve the blood lipid content; others (Bifidobacterium bifidum, Bifidobacterium longum, Lactobacillus acidophilus, Lacticaseibacillus rhamnosus, Enterococcus faecium, and fructo-oligosaccharides) failed in proving any effect on lipid parameters and glucose metabolism. Further studies are necessary for understanding the mechanism of the gut microbiota in childhood obesity and for developing low-cost effective strategies for its management.

Ameliorating effects of L-carnitine and synbiotic co-supplementation on anthropometric measures and cardiometabolic traits in women with obesity: a randomized controlled clinical trial

Background

Obesity, a multifactorial disorder with pandemic dimensions, is conceded a major culprit of morbidity and mortality worldwide, necessitating efficient therapeutic strategies. Nutraceuticals and functional foods are considered promising adjuvant/complementary approaches for weight management in individuals with obesity who have low adherence to conventional treatments. Current literature supports the weight-reducing efficacy of pro/pre/synbiotics or L-carnitine; however, the superiority of the nutraceutical joint supplementation approach over common single therapies to counter obesity and accompanying comorbidities is well documented. This study was designed to assess the effects of L-carnitine single therapy compared with L-carnitine and multistrain/multispecies synbiotic co-supplementation on anthropometric and cardiometabolic indicators in women with obesity.

Methods

The current placebo-controlled double-blind randomized clinical trial was performed on 46 women with obesity, randomly allocated to either concomitant supplementation [L-carnitine tartrate (2 × 500 mg/day) + multistrain/multispecies synbiotic (1 capsule/day)] or monotherapy [L-carnitine tartrate (2 × 500 mg/day) + maltodextrin (1 capsule/day)] groups for 8 weeks. Participants in both groups received healthy eating dietary advice.

Results

Anthropometric, lipid, and glycemic indices significantly improved in both intervention groups; however, L-carnitine + synbiotic co-administration elicited a greater reduction in the anthropometric measures including body mass index (BMI), body weight, and neck, waist, and hip circumferences (p < 0.001, <0.001, <0.001, = 0.012, and =0.030, respectively) after adjusting for probable confounders. Moreover, L-carnitine + synbiotic joint supplementation resulted in a greater reduction in fasting blood sugar (FBS), insulin (though marginal), and homeostatic model assessment of insulin resistance (HOMA-IR) and more increment in quantitative insulin sensitivity check index (QUICKI; p = 0.014, 0.051, 0.024, and 0.019, respectively) compared with the L-carnitine + placebo monosupplementation. No significant intergroup changes were found for the lipid profile biomarkers, except for a greater increase in high-density lipoprotein-cholesterol concentrations (HDL-C) in the L-carnitine + synbiotic group (p = 0.009).

Conclusion

L-carnitine + synbiotic co-supplementation was more beneficial in ameliorating anthropometric indices as well as some cardiometabolic parameters compared with L-carnitine single therapy, suggesting that it is a promising adjuvant approach to ameliorate obesity or associated metabolic complications through potential synergistic or complementary mechanisms. Further longer duration clinical trials in a three-group design are demanded to verify the complementary or synergistic mechanisms.

Clinical trial registration

www.irct.ir, Iranian Registry of Clinical Trials IRCT20080904001197N13.

Effects of Synbiotic Supplementation on Metabolic Syndrome Traits and Gut Microbial Profile among Overweight and Obese Hong Kong Chinese Individuals: A Randomized Trial

In view of the limited evidence showing anti-obesity effects of synbiotics via modulation of the gut microbiota in humans, a randomized clinical trial was performed. Assessment of the metabolic syndrome traits and profiling of the fecal gut microbiota using 16S rRNA gene sequencing in overweight and obese Hong Kong Chinese individuals before and after dietary intervention with an 8-week increased consumption of fruits and vegetables and/or synbiotic supplementation was conducted. The selected synbiotic contained two probiotics (Lactobacillus acidophilus NCFM and Bifidobacterium lactis HN019) and a prebiotic (polydextrose). Fifty-five overweight or obese individuals were randomized and divided into a synbiotic group (SG; n = 19), a dietary intervention group (DG; n = 18), and a group receiving combined interventions (DSG; n = 18). DSG showed the greatest weight loss effects and number of significant differences in clinical parameters compared to its baseline values-notably, decreases in fasting glucose, insulin, HOMA-IR, and triglycerides and an increase in HDL-cholesterol. DSG lowered Megamonas abundance, which was positively associated with BMI, body fat mass, and trunk fat mass. The results suggested that increasing dietary fiber consumption from fruits and vegetables combined with synbiotic supplementation is more effective than either approach alone in tackling obesity.

Intra-Amniotic Administration of Cashew Nut (Anacardium occidentale L.) Soluble Extract Improved Gut Functionality and Morphology In Vivo (Gallus gallus)

Cashew nuts are rich in dietary fibers, monounsaturated fatty acids, carotenoids, tocopherols, flavonoids, catechins, amino acids, and minerals that offer benefits for health. However, the knowledge of its effect on gut health is lacking. In this way, cashew nut soluble extract (CNSE) was assessed in vivo via intra-amniotic administration in intestinal brush border membrane (BBM) morphology, functionality, and gut microbiota. Four groups were evaluated: (1) no injection (control); (2) H₂O injection (control); (3) 10 mg/mL CNSE (1%); and (4) 50 mg/mL CNSE (5%). Results related to CNSE on duodenal morphological parameters showed higher Paneth cell numbers, goblet cell (GC) diameter in crypt and villi, depth crypt, mixed GC per villi, and villi surface area. Further, it decreased GC number and acid and neutral GC. In the gut microbiota, treatment with CNSE showed a lower abundance of Bifidobacterium, Lactobacillus, and E. coli. Further, in intestinal functionality, CNSE upregulated aminopeptidase (AP) gene expression at 5% compared to 1% CNSE. In conclusion, CNSE had beneficial effects on gut health by improving duodenal BBM functionality, as it upregulated AP gene expression, and by modifying morphological parameters ameliorating digestive and absorptive capacity. For intestinal microbiota, higher concentrations of CNSE or long-term intervention may be necessary.

Effect of a Multispecies Synbiotic Supplementation on Body Composition, Antioxidant Status, and Gut Microbiomes in Overweight and Obese Subjects: A Randomized, Double-Blind, Placebo-Controlled Study

Studies investigating the effect of multispecies synbiotic supplementation in obesity management are limited. The current study was performed to evaluate the effects of multispecies probiotics mixed with fructooligosaccharides on body composition, antioxidant status, and gut microbiome composition in overweight and obese individuals. We employed a randomized, double-blind, placebo-controlled trial design, in which 63 individuals aged 18-45 years were assigned to receive either a synbiotic supplement or placebo for 12 weeks. The synbiotic group consumed a daily dose of 37 × 10⁹ colony-forming units (CFU) of a unique blend of seven different probiotics, along with 2 g of fructooligosaccharides, while the placebo group consumed 2 g of maltodextrin daily. Assessments were performed at baseline, week 6, and the end of the study. The results of the study indicated that synbiotic supplementation resulted in a significant reduction in waist circumference and body fat percentage compared to the baseline measurements, as observed at 12 weeks. At the end of the study, there were no significant differences observed in body weight, BMI, waist circumference, or percentage of body fat between the synbiotic group and the placebo group. An analysis of plasma antioxidant capacity revealed that synbiotic supplementation caused a significant increase in Trolox equivalent antioxidant capacity (TEAC) and a concomitant decrease in malondialdehyde (MDA) in the test group when compared to the placebo. For the gut microbiota analysis, synbiotic supplementation significantly decreased Firmicutes abundance and the Firmicutes/Bacteroidetes (F/B) ratio at week 12 as compared to the placebo group. Nevertheless, the synbiotic group did not exhibit any substantial alterations in other biochemical blood parameters compared to the placebo group. These findings suggest that multispecies synbiotic supplementation could be a beneficial strategy to improve body composition, antioxidant status, and gut microbiome composition in overweight and obese subjects.

Effects of synbiotic supplementation on anthropometric indices and body composition in overweight or obese children and adolescents: a randomized, double-blind, placebo-controlled clinical trial

BACKGROUND

Recently, beneficial effects of probiotics and/or prebiotics on cardio-metabolic risk factors in adults have been shown. However, existing evidence has not been fully established for pediatric age groups. This study aimed to assess the effect of synbiotic on anthropometric indices and body composition in overweight or obese children and adolescents.

METHODS

This randomized double-blind, placebo-controlled trial was conducted among 60 participants aged 8-18 years with a body mass index (BMI) equal to or higher than the 85th percentile. Participants were randomly divided into two groups that received either a synbiotic capsule containing 6 × 109 colony forming units (CFU) Lactobacillus coagulans SC-208, 6 × 109 CFU Lactobacillus indicus HU36 and fructooligosaccharide as a prebiotic (n = 30) or a placebo (n = 30) twice a day for eight weeks. Anthropometric indices and body composition were measured at baseline and after the intervention.

RESULTS

The mean (standard deviation, SD) age was 11.07 (2.00) years and 11.23 (2.37) years for the placebo and synbiotic groups, respectively (P = 0.770). The waist-height ratio (WHtR) decreased significantly at the end of the intervention in comparison with baseline in the synbiotic group (0.54 ± 0.05 vs. 0.55 ± 0.05, P = 0.05). No significant changes were demonstrated in other anthropometric indices or body composition between groups.

CONCLUSIONS

Synbiotic supplementation might be associated with a reduction in WHtR. There were no significant changes in other anthropometric indices or body composition.

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

Introduction

Several systematic reviews and meta-analyses have been carried out to assess the impact of synbiotics on lipid profiles and anthropometric parameters. In this regard, an umbrella meta-analysis was performed to provide a more accurate view of the overall impacts of synbiotic supplementation on lipid profile and anthropometric parameters.

Methods

Databases such as PubMed, Scopus, Embase, Web of Science, and Google Scholar were searched for this study from inception to January 2022. A random-effects model was applied to evaluate the effects of synbiotic supplementation on lipid profile and anthropometric parameters. The methodological quality of eligible articles was evaluated using the AMSTAR2 questionnaire. The GRADE approach was used to evaluate the overall certainty of the evidence in the meta-analyses.

Results

Meta-analyses of 17 studies revealed significant decreases in body mass index (BMI) (ES: -0.13 kg/m2; 95% CI: -0.19, -0.06, p < 0.001, I2 = 0.0%, p = 0.870), BW (ES: -1.30 kg; 95% CI: -2.19, -0.41, p = 0.004, I2 = 88.9%, p < 0.001), waist circumference (WC) (ES: -1.80 cm; 95% CI: -3.26, -0.34, p = 0.016, I2 = 94.1%, p < 0.001), low-density lipoprotein cholesterol (LDL-C) (ES: -2.81 mg/dl; 95% CI: -3.90, -1.72, p < 0.001, I2 = 95.1%, p < 0.001), total cholesterol (TC) (ES = -2.24 mg/dl; 95% CI: -3.18, -1.30, p < 0.001, I2 = 94.5%, p < 0.001), and triglyceride (TG) (ES: -0.43 mg/dl; 95% CI: -0.79, -0.07, p = 0.019, I2 = 78.0%, p < 0.001) but not high-density lipoprotein cholesterol (HDL-C) (ES: 0.23 mg/dl; 95% CI: -0.11, 0.56, p = 0.193, I2 = 45.2%, p = 0.051) following synbiotic supplementation.

Discussion

The present umbrella meta-analysis suggests synbiotic supplementation can slightly improve lipid profile and anthropometric indices and might be a therapeutic option for obesity and its related disorders.

Systematic review registration

www.crd.york.ac.uk/prospero, identifier CRD42022304376.

Effects of Fermented Food Consumption on Non-Communicable Diseases

The gastrointestinal flora consists of several microbial strains in variable combinations in both healthy and sick humans. To prevent the risk of the onset of disease and perform normal metabolic and physiological functions with improved immunity, a balance between the host and gastrointestinal flora must be maintained. Disruption of the gut microbiota triggered by various factors causes several health problems, which promote the progression of diseases. Probiotics and fermented foods act as carriers of live environmental microbes and play a vital role in maintaining good health. These foods have a positive effect on the consumer by promoting gastrointestinal flora. Recent research suggests that the intestinal microbiome is important in reducing the risk of the onset of various chronic diseases, including cardiac disease, obesity, inflammatory bowel disease, several cancers, and type 2 diabetes. The review provides an updated knowledge base about the scientific literature addressing how fermented foods influence the consumer microbiome and promote good health with prevention of non-communicable diseases. In addition, the review proves that the consumption of fermented foods affects gastrointestinal flora in the short and long term and can be considered an important part of the diet.

Microbiome-Targeted Therapies as an Adjunct to Traditional Weight Loss Interventions: A Systematic Review and Meta-Analysis

Objective

This study evaluated the effect of microbiome-targeted therapies (pre-, pro-, and synbiotics) on weight loss and other anthropometric outcomes when delivered as an adjunct to traditional weight loss interventions in overweight and obese adults.

Methods

A systematic review of three databases (Medline [PubMed], Embase, and the Cochrane Central Register of Controlled Trials) was performed to identify randomized controlled trials published between January 1, 2010 and December 31, 2020, that evaluated anthropometric outcomes following microbiome-targeted supplements in combination with dietary or dietary and exercise interventions. The pooled mean difference (MD) between treatment and control groups was calculated using a random effects model.

Results

Twenty-one trials with 1233 adult participants (76.4% female) with overweight or obesity were included. Separate meta-analyses were conducted for probiotics (n=11 trials) and synbiotics (n=10 trials) on each anthropometric outcome; prebiotics were excluded as only a single study was found. Patient characteristics and methodologies varied widely between studies. All studies incorporated some degree of caloric restriction, while only six studies included recommendations for adjunct exercise. Compared with dietary or dietary and exercise interventions only, probiotics resulted in reductions in body weight (MD: -0.73 kg; 95% confidence interval [CI]: -1.02 to -0.44, p < 0.001), fat mass (MD: -0.61 kg; 95% CI: -0.77 to -0.45; p<0.001) and waist circumference (MD: -0.53 cm; 95% CI: -0.99 to -0.07, p=0.024) while synbiotics resulted in reductions in fat mass (MD: -1.53 kg; 95% CI: -2.95 to -0.12, p=0.034) and waist circumference (MD: -1.31 cm; 95% CI: -2.05 to -0.57, p<0.001).

Conclusion

This analysis indicates that microbiome-targeted supplements may enhance weight loss and other obesity outcomes in adults when delivered as an adjunct to dietary or dietary and exercise interventions. Personalized therapy to include microbiome-targeted supplements may help to optimize weight loss in overweight and obese individuals.

The effect of synbiotic and vitamin D co-supplementation on body composition and quality of life in middle-aged overweight and obese women: A randomized controlled trial

BACKGROUND & AIMS

Obesity is a worldwide problem which has involved large populations. Since some dietary factors might modify obesity through various signaling pathways, the aim of this study was to investigate the effect of synbiotic plus vitamin D co-supplementation on body composition parameters and quality of life, in middle-aged overweight and obese women.

METHODS

A randomized, controlled, double-blinded trial was performed and 88 overweight and obese women were assigned to 4 groups (22 per group), receiving synbiotic plus vitamin D, synbiotic, vitamin D and placebo for 8 weeks. At the beginning and at the end of the trial, anthropometric indices, body composition indicators, physical activity level, dietary intake, and quality of life score were measured by trained nutritionists. Statistical analysis was performed with SPSS version 22.

RESULTS

The results showed significant difference between 4 groups in waist circumference (WC), fat mass (FM), body fat percentage (BFP) and visceral fat area (VFA) values after 8 weeks of treatment (P = 0.005, P = 0.007, P = 0.003, and P = 0.009, respectively), with the greatest reduction in synbiotic plus vitamin D group compare to placebo. No significant results were demonstrated between groups in relation to other body composition variables. In addition, there were no significant differences between the 4 groups regarding physical, mental and total aspects of life quality over time.

CONCLUSIONS

Our study demonstrated that synbiotic and vitamin D co-supplementation for 8 weeks, had favorable effect on various anthropometric indices and body composition indicators, but no desirable change in life quality score.

CLINICAL TRIAL REGISTRY

IRCT (registration no. IRCT20090822002365N25).

The effect of probiotic and synbiotic supplementation on lipid parameters among patients with cardiometabolic risk factors: a systematic review and meta-analysis of clinical trials

Although the available evidence emphasizes the beneficial effects of probiotics in normalizing various cardiometabolic markers, there is still substantial uncertainty in this regard. Thus, we set out to determine the effect sizes of probiotics on blood lipid parameters more coherently. A systematic literature search of the Medline (PubMed) and Scopus databases was conducted from inception to February 12, 2021, applying both MeSH terms and free text terms to find the relevant randomized controlled trials (RCTs). The meta-analysis was conducted based on a random-effect model to calculate the mean effect sizes demonstrated as weighted mean differences (WMD) and the 95% confidence intervals (95%CI). To explore the heterogeneity, the Cochrane Chi-squared test, and analysis of Galbraith plots were performed. Meta-analysis of data from 40 RCTs (n = 2795) indicated a significant decrease in serum/plasma triglyceride (WMD (95%CI)    -12.26 (-17.11- -7.41) mg/dL; P-value <0.001; I2 (%)= 29.9; P heterogeneity = 0.034)), total cholesterol (with high heterogeneity) (WMD (95%CI)    -8.43 (-11.90- -4.95) mg/dL; P-value <0.001; I2 (%) =56.8; P heterogeneity < 0.001), LDL-C (WMD (95%CI)    -5.08 (-7.61, -2.56) mg/dL; P-value <0.001; I2 (%) =42.7; P heterogeneity =0.002), and HDL-C (with high heterogeneity) (WMD (95%CI)    1.14 (0.23, 2.05) mg/dL; P-value =0.014; I2 (%) = 59.8; P heterogeneity < 0.001) following receiving probiotic/synbiotic supplements. Collectively, the current preliminary evidence supports the effectiveness of probiotics/synbiotics in improving dyslipidemia and various lipid parameters more prominently among subjects with hyperlipidemia, diabetes, and metabolic syndrome. However, large and well conducted RCTs are required to provide further convincing support for these results.

The Effects of Probiotics on Inflammation, Endothelial Dysfunction, and Atherosclerosis Progression: A Mechanistic Overview

INTRODUCTION

The relationship between the intestinal microbiota dysbiosis, inflammation, and cardiovascular disorders (CVDs) has become evident, based on a growing body of literature from animal models and human studies. On the other hand, probiotics are believed to have promising effects on modifying dysbiosis and protecting against CVDs.

OBJECTIVE

This narrative review provides an overview of the link between gut microbiota, inflammation, endothelial dysfunction, and atherosclerosis. The influences of probiotic supplementation on biomarkers contributing to these conditions as the primary underlying risk factors for developing CVDs are also discussed.

METHODS

An up-to-date review was performed of the available evidence from experimental studies, clinical trials, and meta-analyses, considering their challenges and limitations. It also aimed to provide mechanistic insight into the likely mechanisms of probiotics that could prevent atherosclerosis initiation and progression.

RESULTS

Probiotic supplementation seems to be associated with reduced levels of inflammation and oxidative stress biomarkers (C-reactive protein, tumour necrosis factor-α, interleukin (IL)-6, IL-12, and malondialdehyde). Further, these agents might enhance antioxidant factors (IL-10, total antioxidant status, total antioxidant capacity, glutathione, and nitric oxide). Probiotics also appear to improve intestinal barrier integrity, reduce leakage of harmful metabolites (e.g., lipopolysaccharides), inhibit pro-inflammatory signalling pathways, and possibly suppress the formation of trimethylamine/trimethylamine oxide. Probiotics have also been found to enhance endothelial function and halter thrombosis.

CONCLUSION

The current clinical evidence underlines belief that probiotics might be associated with reduced levels of inflammation biomarkers. Experimental evidence reports that the beneficial effects of probiotics seem to be mainly imposed by triggering the secretion of short-chain fatty acids and bile acids, in addition to suppressing the NF-κB signalling pathway. However, the current studies are still in their infancy and it is of high priority to design further research on the topic.

Human microbiome and metabolic health: An overview of systematic reviews

To summarize the microbiome's role in metabolic disorders (insulin resistance, hyperglycemia, type 2 diabetes, obesity, hyperlipidemia, hypertension, nonalcoholic fatty liver disease [NAFLD], and metabolic syndrome), systematic reviews on observational or interventional studies (prebiotics/probiotics/synbiotics/transplant) were searched in MEDLINE and Embase until September 2020. The 87 selected systematic reviews included 57 meta-analyses. Methodological quality (AMSTAR2) was moderate in 62%, 12% low, and 26% critically low. Observational studies on obesity (10 reviews) reported less gut bacterial diversity with higher Fusobacterium, Lactobacillus reuteri, Bacteroides fragilis, and Staphylococcus aureus, whereas lower Methanobrevibacter, Lactobacillus plantarum, Akkermansia muciniphila, and Bifidobacterium animalis compared with nonobese. For diabetes (n = 1), the same was found for Fusobacterium and A. muciniphila, whereas higher Ruminococcus and lower Faecalibacterium, Roseburia, Bacteroides vulgatus, and several Bifidobacterium spp. For NAFLD (n = 2), lower Firmicutes, Rikenellaceae, Ruminococcaceae, whereas higher Escherichia and Lactobacillus were detected. Discriminating bacteria overlapped between metabolic disorders, those with high abundance being often involved in inflammation, whereas those with low abundance being used as probiotics. Meta-analyses (n = 54) on interventional studies reported 522 associations: 54% was statistically significant with intermediate effect size and moderate between-study heterogeneity. Meta-evidence was highest for probiotics and lowest for fecal transplant. Future avenues include better methodological quality/comparability, testing functional differences, new intervention strategies, and considerating other body habitats and kingdoms.

Probiotics in prevention and treatment of cardiovascular diseases

Increasing knowledge of the gut microbiota and its interference in human homeostasis in recent years has contributed to a better understanding of number of different interactions occurring in the gastrointestinal tract. Disruption of the microbiota is detrimental to health and contributes to the development of numerous diseases and may also be an accelerator of pathophysiological processes such as atherosclerosis. Cardiovascular diseases are the most common cause of death worldwide, so the development of new methods to support the treatment and prevention of these diseases becoms one of the priorities of modern medicine. Probiotics may constitute an important element of support in the treatment and prevention of CVD (cardiovascular diseases). A number of papers support such a statement, however, larger clinical trials are needed. Through a number of mechanisms including mitigating inflammation, sealing the intestinal epithelium, and affecting metabolism, probiotics may have a beneficial effect on general health and slow down the pathogenesis of many diseases, including those affecting the cardiovascular system. This article contains a review of current discoveries on the role of probiotics in the prevention and support of CVD treatment.

A narrative review of the role of gastrointestinal dysbiosis in the pathogenesis of polycystic ovary syndrome

Diet-induced gastrointestinal dysbiosis has been hypothesized to play a significant role in stimulating an increase in gastrointestinal permeability and activating systemic inflammation in women with polycystic ovary syndrome (PCOS). We reviewed the current proof-of-concept studies on the proposed mechanism of dysbiosis in the pathogenesis of PCOS. A literature search was performed to identify articles on changes in the intestinal microbiome (dysbiosis) and increased intestinal mucosal permeability involving lipopolysaccharide (LPS), LPS-binding protein (LPS-BP), and zonulin. We also searched for systematic reviews and meta-analyses that synthesized the results of studies on the therapeutic effects of prebiotics, probiotics, or synbiotics in women with PCOS. Our search was confined to human studies between 2012 and 2021 using the PubMed, Scopus, and Cochrane databases. Thirty-one studies met the inclusion criteria (14 microbiota, 1 LPS, 1 LPS-BP, 1 LPS and LPS-BP, 5 zonulin, 9 systematic reviews). Our analysis revealed that most studies reported reduced alpha diversity and dysbiosis in women with PCOS. Preliminary studies suggest that LPS, LPS-BP, and zonulin may be involved in the pathophysiology of increased intestinal permeability. Treatment of PCOS with prebiotics, probiotics, and synbiotics appears to have a range of beneficial effects on metabolic and biochemical profiles. This review highlights the need for continued research into the pathophysiological mechanisms of dysbiosis and the clinical efficacy of prebiotics, probiotics, and synbiotics in women with PCOS.

Acute and short-term effects of Lactobacillus paracasei subsp. paracasei 431 and inulin intake on appetite control and dietary intake: A two-phases randomized, double blind, placebo-controlled study

This study aims to examine the acute and short-term effects of prebiotics, probiotics, and their combination on appetite, energy intake and satiety related hormones in two phases. The first phase was a randomized, double blind, placebo controlled crossover study. Prebiotic (16 g inulin), probiotic (Lactobacillus paracasei subsp. paracasei 431 (L. casei 431) (>10⁶ cfu/ml), synbiotic (their combination) and control (16 g maltodextrin) dairy drinks were consumed by 16 healthy men with a standard breakfast on four separate test days, and the following satiety responses and ad libitum food intake at lunch and over 24 h were assessed. In the second phase, the effects of 21 days of synbiotic (n = 10) or control (n = 11) drink consumption on appetite sensation, energy intake, serum glucose, insulin, peptide YY, ghrelin, obestatin and adiponectin concentration were assessed in a randomized double-blind placebo-controlled design. In the first phase, energy intake values during ad libitum lunch were the lowest in the prebiotic drink, followed by probiotic, synbiotic and control drinks, respectively (p = 0.017); also the rest of the day and 24-h dietary energy intake was lower by prebiotic and probiotic drinks compared to the control drink (p < 0.05 for each). For short-term effects, no significant difference in anthropometric measurements, hunger-satiety scores and serum glucose, insulin, PYY, ghrelin, obestatin and adiponectin concentrations were recorded. Despite the potential of prebiotics and probiotics to reduce energy intake, further studies are required for a better understanding of their role in satiety related mechanisms.

Effects and Mechanisms of Probiotics, Prebiotics, Synbiotics, and Postbiotics on Metabolic Diseases Targeting Gut Microbiota: A Narrative Review

Metabolic diseases are serious threats to public health and related to gut microbiota. Probiotics, prebiotics, synbiotics, and postbiotics (PPSP) are powerful regulators of gut microbiota, thus possessing prospects for preventing metabolic diseases. Therefore, the effects and mechanisms of PPSP on metabolic diseases targeting gut microbiota are worth discussing and clarifying. Generally, PPSP benefit metabolic diseases management, especially obesity and type 2 diabetes mellitus. The underlying gut microbial-related mechanisms are mainly the modulation of gut microbiota composition, regulation of gut microbial metabolites, and improvement of intestinal barrier function. Moreover, clinical trials showed the benefits of PPSP on patients with metabolic diseases, while the clinical strategies for gestational diabetes mellitus, optimal formula of synbiotics and health benefits of postbiotics need further study. This review fully summarizes the relationship between probiotics, prebiotics, synbiotics, postbiotics, and metabolic diseases, presents promising results and the one in dispute, and especially attention is paid to illustrates potential mechanisms and clinical effects, which could contribute to the next research and development of PPSP.

Interactions between the Gut Microbiome, Lung Conditions, and Coronary Heart Disease and How Probiotics Affect These

The importance of a healthy microbiome cannot be overemphasized. Disturbances in its composition can lead to a variety of symptoms that can extend to other organs. Likewise, acute or chronic conditions in other organs can affect the composition and physiology of the gut microbiome. Here, we discuss interorgan communication along the gut–lung axis, as well as interactions between lung and coronary heart diseases and between cardiovascular disease and the gut microbiome. This triangle of organs, which also affects the clinical outcome of COVID-19 infections, is connected by means of numerous receptors and effectors, including immune cells and immune-modulating factors such as short chain fatty acids (SCFA) and trimethlamine–N–oxide (TMAO). The gut microbiome plays an important role in each of these, thus affecting the health of the lungs and the heart, and this interplay occurs in both directions. The gut microbiome can be influenced by the oral uptake of probiotics. With an improved understanding of the mechanisms responsible for interorgan communication, we can start to define what requirements an ‘ideal’ probiotic should have and its role in this triangle.

Ultra-processed food consumption and adult obesity risk: a systematic review and dose-response meta-analysis

We performed this systematic review and meta-analysis to evaluate observational studies assessing the association between ultra-processed food (UPF) consumption and the risk of overweight, obesity, and abdominal obesity in the general population. We searched the databases PubMed/MEDLINE, Scopus, Embase, and ISI Web of Science from inception until December 2020. Data were extracted from 12 studies (nine cross-sectional and three cohort studies). Odds ratio (OR) were pooled using a random-effects model. UPF consumption was associated with an increased risk of obesity (OR = 1.55; 95% CI: 1.36, 1.77; I² = 55%), overweight (OR = 1.36; 95% CI: 1.14, 1.63; I² = 73%), and abdominal obesity (OR = 1.41; 95% CI: 1.18, 1.68; I² = 62%). Furthermore, every 10% increase of UPF consumption in daily calorie intake was associated with a 7%, a 6%, and a 5% higher risk of overweight, obesity, and abdominal obesity, respectively. Dose-response meta-analysis of cross-sectional studies showed a positive linear association between UPF consumption and abdominal obesity. There was also a positive linear association between UPF consumption and risk of overweight/obesity in the analysis of cross-sectional studies and a positive monotonic association in the analysis of cohort studies. Our study suggests that UPF consumption is associated with an increased risk of excess weight or abdominal obesity.

The effect of almond intake on anthropometric indices: a systematic review and meta-analysis

This systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to summarize the effect of almond intake on anthropometric indices in adult subjects. We searched PubMed, Scopus, ISI Web of Science, Cochrane Library, and Google Scholar databases until January 2020 to identify relevant RCTs. Data were reported as weighted mean differences (WMDs) and standard deviations (SDs) to show the magnitude of effects of almond on body weight (BW), body mass index (BMI), waist circumference (WC), fat mass (FM), and fat-free mass (FFM). Out of 2983 reports, 28 RCTs (37 arms) were eligible for including in our meta-analysis. The pooled results, obtained using a random-effects model, showed that almond intake significantly decreased BW (WMD: -0.38 kg, 95% CI: -0.65, -0.10, p = 0.007, I2 = 30.5%) and FM (WMD: -0.58 kg, 95% CI: -0.87, -0.28, p < 0.001, I2 = 4.9%). However, we found no significant effect of almond administration on BMI (WMD: -0.30 kg m-2, 95% CI: -0.67, 0.06, p = 0.101, I2 = 62.6%), WC (WMD: -0.60 cm, 95% CI: -1.28, 0.06, p = 0.078, I2 = 0.0%), and FFM (WMD: 0.23 kg, 95% CI: -0.04, 0.50, p = 0.097, I2 = 49.5%). Overall, the current meta-analysis demonstrated that resveratrol almond intake significantly reduced weight and FM, but did not affect BMI, WC, and FFM. Further studies are still required to confirm our results.

Probiotics Can Further Reduce Waist Circumference in Adults with Morbid Obesity after Bariatric Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Whether probiotics could be used as an adjunct to bariatric surgery is controversial. This meta-analysis aimed to evaluate the effects of probiotics on body weight, body mass index (BMI), percentage of the excess weight loss (%EWL), waist circumference (WC), and C-reactive protein (CRP) in adults with obesity after bariatric surgery (BS). PUBMED, EMBASE, and the Cochrane Central Registry of Controlled Trials were searched from the earliest record to March 2020. All randomized controlled trials (RCTs) on the effects of probiotics in adults with obesity after bariatric surgery were analyzed according to the eligibility criteria. Four RCTs, including 172 participants, were analyzed. There was a statistically significant difference in probiotics in the reduction of waist circumference at 12 months after bariatric surgery. However, probiotics were not effective in weight, BMI, %EWL, WC, and CRP both within 3 months and at 12 months postoperation. Probiotics aid adults with morbid obesity in achieving further waist circumference improvement after BS, with no significant effect on weight, BMI, %EWL, and CRP. More quality clinical studies are needed to confirm the efficacy and safety of probiotics, and address a number of practical issues before the routine clinical use of probiotics in adults with obesity undergoing BS.

Efficacy of synbiotic interventions on blood pressure: a systematic review and meta-analysis of clinical trials

PURPOSE

The present systematic review and meta-analysis aimed to evaluate the effect of synbiotic interventions on blood pressure levels in adults.

METHODS

A systematic literature search was conducted in the databases of MEDLINE, Scopus, Web of Science, and Cochrane through March 2020 to identify all randomized control trials (RCTs) investigating the effects of synbiotic interventions on blood pressure parameter, including systolic (SBP) and diastolic blood pressure (DBP). Grading of Recommendations Assessment, Development and Evaluation (GRADE) scale was used to assess the certainty of evaluated outcomes and determine the strength of recommendations.

RESULTS

Eleven RCTs were included in the meta-analysis. Synbiotic interventions significantly reduced SBP (-3.02 mmHg; 95% CI: -4.84, -1.21; I² = 55%) without changing DBP levels (-0.57 mmHg; 95% CI: -1.78, 0.64; I² = 50%). Subgroup analyses revealed that the SBP-lowering effects of synbiotic interventions were more pronounced wherein trials were longer (≥12 weeks), synbiotic interventions were administrated as a supplement, and participants were younger (<50 years old). Also, a significant improvement in both SBP and DBP levels was evident in subgroups with a lower (<30 kg/m²) body mass index.

CONCLUSIONS

Synbiotic interventions may significantly improve SBP levels in adults.

Probiotics as a therapeutic strategy in obesity and overweight: a systematic review

Obesity and overweight are two of the most health challenges with an increasing prevalence in recent years, in which several complications have been identified to have a high impact in patients' health conditions. In this vein, an increasing interest in the gut microbiota has emerged as a target for therapeutic strategies in obesity and overweight due to its direct relation with the aforementioned health conditions and complications. Thus, the aim of this study was to evaluate the efficacy of probiotics as a therapeutic strategy in the management of obesity and overweight. A systematic review of randomised controlled trials was carried out in 6 databases until May 2019 to assess the use of probiotics in obesity and overweight patients. The Jadad Scale was used to assess the quality of the clinical trials. Twenty-three clinical trials published between 2000 and 2019 met the inclusion criteria. The role of probiotics in reducing body mass index and weight as well as changing the visceral abdominal fat area, waist and hip circumference were shown in 14 of 23 trials (60.87%); 14 trials (60.87%) showed changes on patients' fatty acids and biomarkers; and 4 trials (17.39%) studied the role of the gut microbiota in obese and overweight patients. Some probiotics strains are shown to be effective in reducing body mass index and hip circumference. This review provides evidence of successful results in weight loss using probiotic groups.

Effects of probiotic and alpha-lipoic acid supplements, separately or in combination on the anthropometric indicators and maintenance of weight in overweight individuals

BACKGROUND & AIMS

Weight loss after proper diet is one of the main topics in nutrition. This study was designed to evaluate the effects of probiotic and alpha-Lipoic acid (ALA) supplements on the anthropometric indicators and maintenance of weight in overweight individuals.

METHODS

This study consisted of two phases of weight loss (8 weeks) and weight maintenance (16 weeks). Eighty-eight overweight participants were randomly divided into 4 groups in phase 1: isocaloric diet with probiotic (500 mg), an isocaloric diet with ALA (600 mg) and probiotic, an isocaloric diet with ALA and isocaloric diet with placebo. In phase 2, participants received a normal diet with the mentioned supplements. In the beginning, end of the phase 1, and at the end of phase 2, weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), body fat percentage, and blood pressure (BP) were measured. Also, 10 cc blood samples were taken from subjects to measure C-reactive protein (CRP). Data was analyzed using SPSS software.

RESULTS

At the end of the two phases, the differences of changes in the probiotic + ALA group was significant in weight, WC, and CRP factors when compared to the other groups (P < 0.05). Also, at the end of the study, maintain a reduced weight was significantly higher in the probiotic + ALA group than in the other groups (P < 0.05).

CONCLUSION

According to findings, probiotics and ALA supplementation with normal diet help to maintain decreased weight after adhering to a weight loss diet. This may be due to the reduction of inflammation.

TRIAL REGISTRATION

(IRCT20141025019669N10).

Effect of sour tea supplementation on liver enzymes, lipid profile, blood pressure, and antioxidant status in patients with non-alcoholic fatty liver disease: A double-blind randomized controlled clinical trial

The aim of this study was to evaluate the efficacy of sour tea supplementation in patients with nonalcoholic fatty liver disease (NAFLD). Seventy NAFLD patients were enrolled in this randomized, double-blind, placebo-controlled clinical trial. Participants received sour tea in the form of a 450 mg capsule or a placebo capsule daily for 8 weeks. Anthropometric indices, liver enzymes, lipid profile, blood pressure, and antioxidant status were evaluated at the baseline and at the end of the study. Sixty-one participants completed the study. After 8 weeks, sour tea administration significantly decreased serum triglyceride (TG) (p = .03), alanine aminotransferase (ALT) (p = .01), and aspartate aminotransferase (AST) (p = .004) levels compared with the placebo. In addition, sour tea supplementation resulted in a significant reduction in systolic blood pressure (SBP) (p = .03) and diastolic blood pressure (DBP) (p = .04), and a significant increase in serum total antioxidant capacity (TAC) levels (p ˂ .001) compared with the placebo. However, no significant changes in anthropometric measures, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) levels were observed after sour tea supplementation compared with the placebo (p > .05). Sour tea supplementation may be effective in improving serum TG, liver enzymes, and blood pressure in patients diagnosed with NAFLD. Further studies are needed to address the exact mechanism of action of these effects.

The effect of synbiotics supplementation on anthropometric indicators and lipid profiles in women with polycystic ovary syndrome: a randomized controlled trial

Background

Different therapies have been suggested for polycystic ovary syndrome (PCOS), but changes in lifestyle and diet have been considered. Diet and dietary factors can be very effective in modifying the disease. The positive effects of probiotic and synbiotics supplementation on improving lipid profiles and anthropometric indices have been examined in various diseases. This study was conducted to evaluate the effects of synbiotics supplementation on lipid and anthropometric profiles in infertile women with PCOS.

Methods

PCOS patients aged 19–37 years old were randomized to receive either synbiotics supplement (n = 50) or placebo (n = 49) for 12 weeks.

Results

Consumption of synbiotics compared to the placebo, resulted in a significant decrease in Low-density lipoprotein cholesterol (LDL) value (Change Mean Difference (CMD): 4.66, 95%CI: 0.20, 9.13) and a significant increase in high-density lipoprotein cholesterol (HDL) (CMD: 1.80, 95%CI: 0.34, 3.26). Although we failed to find a significant effect of synbiotics consumption on total cholesterol (TC) and triglyceride (TG) levels. We did not find differences in anthropometric indices between groups.

Conclusions

Overall, 12 weeks of synbiotics supplementation among PCOS women resulted in beneficial effects on LDL and HDL, although it is not yet clear how much our findings are clinically significant and more clinical studies with larger sample sizes are still needed.

Trial registration

Iranian Registry of clinical Trial, IRCT.ir, ID: IRCT2014110515536N2. Registered on 19 December 2015.

Graphical abstract

The impact of probiotics, prebiotics, and synbiotics on the biochemical, clinical, and immunological markers, as well as on the gut microbiota of obese hosts

Obesity is currently considered a global epidemic and it leads to several alterations on the human body and its metabolism. There are evidences showing that the intestinal microbiota can influence on the pathogenesis of obesity. Microbiota plays a vital role not only in the digestion and absorption of nutrients, but also in the homeostatic maintenance of host immunity, metabolism, and gut barrier. Its dietary alteration is an important target in the treatment of obesity. Emerging evidence suggests that modifying the composition of the gut microbiota through probiotic, prebiotic, and synbiotic supplementation may be a viable adjuvant treatment option for obese individuals. In this review, the impact of probiotics, prebiotics, and synbiotics on the anthropometric profile, biochemical regulation, clinical, and immunological markers, as well as on the gut microbiota of obese hosts is described. It also emphasizes how changes in the composition and/or metabolic activity of the gut microbiota through the administration of nutrients with probiotic, prebiotic, or synbiotic properties can modulate the host's gene expression and metabolism, and thereby positively influence on the host's adipose tissue development and related metabolic disorders. The beneficial effects on the host's metabolism promoted by prebiotics, probiotics, and synbiotics have been successfully demonstrated by several studies. However, further investigation is needed to fully explain the cellular mechanisms of action of probiotics and prebiotics on human health, and also to elucidate the relationship between microbiota and obesity etiology, using well-designed, long-term, and large-scale clinical interventions.

The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of synbiotics

In May 2019, the International Scientific Association for Probiotics and Prebiotics (ISAPP) convened a panel of nutritionists, physiologists and microbiologists to review the definition and scope of synbiotics. The panel updated the definition of a synbiotic to "a mixture comprising live microorganisms and substrate(s) selectively utilized by host microorganisms that confers a health benefit on the host". The panel concluded that defining synbiotics as simply a mixture of probiotics and prebiotics could suppress the innovation of synbiotics that are designed to function cooperatively. Requiring that each component must meet the evidence and dose requirements for probiotics and prebiotics individually could also present an obstacle. Rather, the panel clarified that a complementary synbiotic, which has not been designed so that its component parts function cooperatively, must be composed of a probiotic plus a prebiotic, whereas a synergistic synbiotic does not need to be so. A synergistic synbiotic is a synbiotic for which the substrate is designed to be selectively utilized by the co-administered microorganisms. This Consensus Statement further explores the levels of evidence (existing and required), safety, effects upon targets and implications for stakeholders of the synbiotic concept.

Does synbiotic supplementation affect body weight, body mass index, and high-sensitivity C-reactive protein levels in patients with type 2 diabetes? Protocol for a systematic review and meta-analysis

BACKGROUND

The number of patients with type 2 diabetes mellitus (T2DM) is surging currently. Synbiotic as a supplement based on gut microbiota may be beneficial to improve the metabolism of T2DM. However, the results of clinical studies show that the role of synbiotic in weight management in patients with T2DM is controversial. In this context, we have formulated this protocol. The study will evaluate the effects of synbiotic supplementation on body weight, body mass index (BMI), and high-sensitivity C-reactive protein (hs-CRP) levels in patients with T2DM.

METHODS

The electronic databases PubMed, Embase, and the Cochrane Library will be searched for relevant literature from inception. Literature search, data extraction, and methodological quality assessment will be carried out independently by two researchers. All randomized controlled trials (RCTs) that met the criteria will be included. A meta-analysis will be conducted using weighted mean difference (WMD) and 95% confidence interval (CI) as effect measures.

RESULTS

This systematic review and meta-analysis will mainly assess the effects of synbiotic supplementation on body weight and BMI in T2DM patients. Secondary outcome indicators will include hs-CRP.

CONCLUSION

This systematic review and meta-analysis will quantify the value of synbiotic supplement in weight management of patients with T2DM through a comprehensive evaluation of the current clinical evidence, so as to provide a basis for clinical application.

PROSPERO REGISTRATION NUMBER

CRD42019132974.