Dysbiosis, Small Intestinal Bacterial Overgrowth, and Chronic Diseases

2021 ◽  
pp. 334-362
Author(s):  
Ana Rita Silva ◽  
Maria Alexandra Bernardo ◽  
Maria Fernanda Mesquita ◽  
José Vaz Patto ◽  
Pedro Moreira ◽  
...  
Keyword(s):  
Chronic Diseases ◽  
Intestinal Microbiota ◽  
Food Additives ◽  
Bacterial Overgrowth ◽  
Nutritional Therapy ◽  
Small Intestinal Bacterial Overgrowth ◽  
Bioactive Molecules ◽  
Mucosal Barrier ◽  
Intestinal Bacterial Overgrowth ◽  
Small Intestinal

Dysbiosis is characterized by an alteration in quantity and quality of intestinal microbiota composition. In the presence of dysbiosis, enterocytes will have difficulty in maintaining the integrity of the mucosal barrier, leading to increased intestinal permeability. These events are recognised to be linked to several chronic diseases. One of the consequences of dysbiosis is the manifestation of small intestinal bacterial overgrowth (SIBO), which is associated to a variety of chronic diseases. Single food nutrients and bioactive molecules, food additives, pre- and probiotics, and different dietary patterns may change the composition of the intestinal microbiota. Low FODMAPs diet has been a reference in SIBO treatment. This chapter intends to describe how the intestinal microbiota, dysbiosis, and SIBO can be related; to define dysbiosis food and nutrients influence; and to offer some nutritional therapy strategies for applying the low FODMAPs protocol, enabling better adherence by patients in order to increase their wellbeing.

Small Intestinal Bacterial Overgrowth Is Associated with Non- Alcoholic Fatty Liver Disease

2016 ◽  
Vol 25 (2) ◽  
pp. 159-165 ◽  
Author(s):  
Andrea Fialho ◽  
Andre Fialho ◽  
Prashanthi Thota ◽  
Arthur J. McCullough ◽  
Bo Shen
Keyword(s):  
Risk Factors ◽  
Fatty Liver Disease ◽  
Bacterial Overgrowth ◽  
Small Intestinal Bacterial Overgrowth ◽  
Study Group ◽  
Alcoholic Fatty Liver ◽  
Intestinal Bacterial Overgrowth ◽  
Small Intestinal ◽  
Alcoholic Fatty Liver Disease

Background: Changes in gut bacteria play a role in type 2 diabetes mellitus (DM) and hepatic steatosis. There is a lack of studies evaluating the frequency and risk factors for non-alcoholic fatty liver disease (NAFLD) in patients tested for small intestinal bacterial overgrowth (SIBO). Aim: To evaluate the frequency of NAFLD and associated risk factors in patients tested for SIBO. Methods: In this case-control study, 372 eligible patients submitted to glucose hydrogen/methane breath test for SIBO who also had an abdominal imaging study were included. Patients were divided into SIBO-positive and SIBO-negative groups. Clinical, demographic and laboratory variables were evaluated in addition to the presence of NAFLD on abdominal imaging. Results: Of the 372 eligible patients, 141 (37.9%) were tested positive for SIBO (study group) and 231 (62.1%) were negative for it (control group). NAFLD occurred in 45.4% (64/141) of the study group compared to 17.3% (40/231) of the control group (p<0.001). Patients in the study group were found to have higher rates of elevated aspartate aminotransferase (AST) (20.6% vs. 11.3%; p=0.034) and alanine aminotransferase (ALT) levels (56.0% vs. 40.7%; p= 0.039), type 2 diabetes (23.4% vs. 13.9%; p=0.041), hypertension (54.6% vs. 40.3%; p=0.046) and metabolic syndrome (78.0% vs. 60.2%; p=0.020). In the multivariate analysis, SIBO (odds ratio [OR]: 1.95; 95% confidence interval [CI]: 1.14-3.31; p=0.014), type 2 DM (OR: 3.04; 95%CI: 1.57-5.90; p=0.001) and obesity (OR: 3.58; 95%CI: 1.70-7.54; p=0.001) remained associated with NAFLD.Conclusion: Patients with SIBO have an increased risk for hepatic steatosis and may benefit from aggressive control of the risk factors for NAFLD including metabolic syndrome. Abbreviations: ALT: alanine aminotransferase; AST: aspartate aminotransferase; BMI: body mass index; CTE: computed tomography enterography; DM: diabetes mellitus; ETOH: ethanol; IL: interleukin; LPS: lipopolysaccharide; NAFLD: non-alcoholic fatty liver disease; NASH: non-alcoholic steatohepatitis; PPI: proton pump inhibitor; SIBO: small intestinal bacterial overgrowth; TLR-4: toll-like receptor 4; TMAO: trimethylamine-N-oxide (TMAO); TNF-α: tumor necrosis factor alpha.

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