The effects of probiotics, prebiotics, and synbiotics on polycystic ovarian syndrome: an overview of systematic reviews.

Introduction: Accumulating evidence has highlighted the critical role of the gut microbiota and its potential action as a regulator of metabolic disorders including insulin resistance, obesity, and systemic inflammation in polycystic ovarian syndrome (PCOS). Microbiota-modulating interventions, such as probiotics, prebiotics, and synbiotics, could be effective in PCOS management. Methods: We conducted an overview of systematic reviews (SRs) and meta-analyses to summarize reviews regarding the effectiveness of probiotics/prebiotics/synbiotics on the management of PCOS through a systematic literature search in PubMed, Web of Science, and Scopus databases until September 2021. Results: Eight SRs and meta-analyses were included in this study. Our overview confirmed that probiotic supplementation had a potentially beneficial effect on some PCOS-related parameters including body mass index (BMI), fasting plasma glucose (FPG), and lipid profiles. Evidence shows that synbiotics in comparison with probiotics were less effective on these parameters. The methodological quality of SRs was assessed using the AMSTAR-2 assessment tool and was determined as high for four SRs, low for two SRs, and critically low for one SR. Due to limited evidence and high heterogeneity of the studies, it remains difficult to identify optimal probiotics strains, prebiotics types, length of duration, and doses. Discussion: Future clinical trials with higher quality are recommended to clarify the efficacy of probiotics/prebiotics/synbiotics on the management of PCOS and provide more accurate evidence.

The Effect of a Moderately Restricted Carbohydrate Diet on Cardiometabolic Risk Factors in Overweight and Obese Women With Metabolic Syndrome: A Randomized Controlled Trial.

PURPOSE: Metabolic syndrome (MetS) is a major public health concern that increases the risk of cardiovascular disease and mortality. In previous studies of MetS management, low-carbohydrate diets have been strongly emphasized, despite the fact that many apparently healthy individuals have difficulties adhering to these diets on a long-term basis. The purpose of the present study was to elucidate the effects of a moderately restricted carbohydrate diet (MRCD) on cardiometabolic risk factors in women with MetS. METHODS: This parallel 3-month, single-blind randomized controlled trial was conducted in Tehran, Iran, among 70 women with overweight or obesity aged 20 to 50 years with MetS. Patients were randomly allocated to receive either MRCD (42%-45% carbohydrates and 35%-40% fats) (n = 35) or a normal weight loss diet (NWLD) (52%-55% carbohydrates and 25%-30% fats) (n = 35). Both diets contained the same quantity of protein, which accounted for 15% to 17% of total energy. Anthropometric measurements, blood pressure, lipid profile, and glycemic indices were all assessed before and after the intervention. FINDINGS: Compared with the NWLD group, following an MRCD significantly decreased weight (-4.82 vs -2.40 kg; P = 0.01), body mass index (-1.88 vs -0.94 kg/m2; P = 0.01), waist circumference (-5.34 vs -2.75 cm; P = 0.01), hip circumference (-2.58 vs -1.11 cm; P = 0.01), serum triglyceride (-26.8 vs -7.19 mg/dL; P = 0.01), and increased serum HDL-C levels (1.89 vs. 0.24 mg/dL; P = 0.01). There was no significant difference between the 2 diets in waist-to-hip ratio, serum total cholesterol, serum LDL-C, systolic and diastolic blood pressure, fasting blood glucose, insulin levels, or the homeostasis model assessment for insulin resistance. IMPLICATIONS: Moderate carbohydrate replacement with dietary fats significantly improved weight, body mass index, waist circumference, hip circumference, serum triglyceride, and HDL-C levels among women with MetS. Iranian Registry of Clinical Trials identifier: IRCT20210307050621N1.

The critical role of gut microbiota dysbiosis in skeletal muscle wasting: a systematic review.

AIMS: Skeletal muscle wasting is affected by the gut microbiota dysbiosis through multiple pathways, including inflammatory process, defected immune system, and anabolic resistance. We aimed to systematically review the studies investigating the gut microbiota composition in sarcopenic and cachexic humans and animals. METHODS: We carried out a comprehensively systematic search using relevant keywords on PubMed, Web of Science, and Scopus databases until July 2021. Original human observational research and animal studies related to our research topics published in English were selected. RESULTS: Seven human studies and five animal studies were included. Three human studies were case-control, whereas the other four were cross-sectional studies that investigated three different conditions, including age-related sarcopenia, as well as liver cirrhosis and cancer cachexia. The principal alteration in age-related sarcopenia and liver cirrhosis-induced sarcopenia was a reduction in short-chain fatty acids (SCFAs) -producing bacteria. Lachnospiraceae family, consisting of Lachnospira, Fusicatenibacter, Roseburia, and Lachnoclostridium, significantly decreased in age-related sarcopenia, while in liver cirrhosis-induced sarcopenia, the alpha diversity of gut microbiota decreased compared with the control group. Moreover, Enterobacteriaceae, which has a pro-inflammatory effect increased in muscle-wasted animals. CONCLUSION: This systematic review presents associations between the gut microbiota alterations and skeletal muscle wasting as a consequence of various pathologies, including aging sarcopenia, renal failure, and cancer cachexia in both human and animal studies.

The Role of Gut Microbiota-Brain Axis in Pathophysiology of ADHD: A Systematic Review.

OBJECTIVE: The main goal of this systematic review is to summarize evidences regarding alterations of microbial composition in ADHD cases and uncover underlying mechanisms. METHODS: A comprehensive search was conducted on PubMed, Web of Science, and Scopus databases up to March 2021. All the observational studies including case-control, cross-sectional, and cohorts investigating the correlations between the gut microbiota and ADHD in both adults and children were included. RESULTS: We found eight eligible studies. Enterococcus, Bifidobacterium, and Odoribacter were increased which may lead to impaired dopamine related functions in CNS. Moreover, decrease of Faecalibacterium frequency in ADHD could result in higher permeability and crossing of inflammatory cytokines. Regarding the short chain fatty acids-producing bacteria, Ruminococcaceae family decreased and Bacteroides uniformis and Bacteroides ovatus species increased. CONCLUSION: Gut microbiota correlation with ADHD and its underlying mechanisms could open new windows for developing novel therapies of ADHD by manipulating microbiota.