Study Type: A prospective, proof-of-concept, interventional study on gut microbiota composition and function in patients with metabolic syndrome,and/or type 2 diabetes and/or obesity treated with standard therapy Sponsor-investigator: Profit study Local investigators/ subinvestigators Principal Investigator: Prof. Antonio Gasbarrini Sub-Investigators: to be defined Protocol Version and Date: Version 1, 08th July 2019 Trial management and coordinating facility: Fondazione Policlinico Universitario Agostino Gemelli IRCCS Center for Digestive Diseases Internal Medicine and Gastroenterology Unit Largo Agostino Gemelli, 8 00168 Rome Italy CLINICAL STUDY PROTOCOL INVESTIGATOR SIGNATURE PAGE Study Title: A prospective, proof-of-concept, clinical study on gut microbiota in patients with metabolic syndrome, type 2 diabetes and obesity The Principal-Investigator has approved the protocol version dated and confirms hereby to conduct the study according to the protocol, current version of the World Medical Association Declaration of Helsinki, ICH-GCP guidelines, ISO 14155 norm and the local legally applicable requirements. 1. Background Gut microbiota and metabolic syndrome (MS) Recently, the role of gut microbiota in metabolic syndrome and associated diseases gained interest among researchers. Metabolic syndrome is defined by a clustering of metabolic disorders that include central adiposity with visceral fat accumulation, dyslipidemia, insulin resistance, dysglycemia and non-optimal blood pressure levels and it is associated with an increased risk of cardiovascular diseases and type 2 diabetes. In fact, gut microbiota could have a role in regulation of body weight and energy homeostasis, influencing extraction of calories from food and their storage in host adipose tissue. Furthermore, gut microbiota in obese and lean individuals differs in the ability to play these functions. At the moment, the first line standard therapy for MS consists in dietary and lifestyle intervention. 2. Objectives The primary aim of this study is to evaluate the effects on microbiota of current standard medical treatment for MS, type 2 diabetes and obesity, including microbiome composition characterization based on metagenomic analysis of stools and saliva and genotyping of blood and functional characterization based on metabolomics analysis on urine and blood. Secondary aims will include clinical efficacy of treatments and correlation with microbiome and metabolome characterization.