1. Specific Aim 1 will determine the impact of a probiotic on circulating leptin and TMAO levels, conventional risk factors for cardiovascular disease and diabetes (total cholesterol, LDL cholesterol, oxidized LDL, triglycerides, C-reactive protein, serum amyloid A, fibrinogen and adiponectin, glucose-dependent- insulinotropic polypeptide (GIP), glucagon-like-peptide (GLP-1), glucagon, insulin), and their relationship to the intestinal microbiota (15 representative microbial groups) as non conventional risk factors. Several blood samples will be collected to measure biomarkers. Participants will provide periodic stool samples in order to measure gut bacterial biodiversity. Lastly, endothelial cell function (flow mediated dilation) will be measured in order to assess blood vessel function.