Metabolically Healthy Obesity

Population aging has been accompanied by a rise in obesity and other chronic diseases, increasing cardiovascular risk particularly among women, who exhibit a higher prevalence in older age groups compared to men. Aging and obesity share pathophysiological mechanisms, such as chronic inflammation and oxidative stress. However, distinct obesity phenotypes exist, such as metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO). Consequently, therapeutic interventions involving nutritional strategies and physical training are highly relevant, especially for older women. Taurine, a sulfur-containing amino acid, plays a role in modulating oxidative stress, inflammation, osmoregulation, and mitochondrial function. Rationale: Plasma taurine concentrations are lower in women with obesity compared to healthy individuals. However, studies investigating these concentrations across different phenotypes-particularly in older women, a group susceptible to functional and metabolic changes-remain limited. Understanding these variations could clarify taurine's role in the pathophysiology of obesity and aging and inform personalized therapeutic strategies. Combined physical training stands out as an effective strategy for modulating inflammatory, oxidative, and metabolic pathways, in addition to improving psychosocial aspects. Given that taurine levels can be influenced by these pathways, investigating the taurine response to physical training across different metabolic phenotypes may contribute to developing low-cost interventions aimed at improving the quality of life for older women with obesity.

The goals of this research study are to: 1) understand why some people with obesity are protected from developing conditions such as type 2 diabetes and cardiovascular disease while others are more likely to develop obesity-related conditions; 2) assess the effect of small extracellular vesicles (sEVs also called exosomes), obtained from human participants, on metabolic function in cultured cells and in mice.

The investigators seek to better understand how a single high-fat meal impacts gut, immune, and vascular outcomes in individuals with "metabolically healthy obesity" (obesity and largely normal cardiometabolic profile) and "metabolically healthy normal-weight individuals." Second, the investigators seek to understand how a prebiotic fiber (inulin) impacts gut, immune, and vascular outcomes in individuals with "metabolically healthy obesity."

This study aims to develop a non-invasive diagnostic method for metabolic syndrome (MetS) and metabolically healthy obesity (MHO) through analysis of exhaled air. Using proton-transfer-reaction mass spectrometry combined with machine learning algorithms, we will characterize volatile organic compound profiles in 300 participants across three groups: MetS patients, MHO patients, and healthy controls. The primary goal is to create and validate a classification model capable of accurately differentiating these metabolic states based on breath analysis.

Based on prior research, the investigators are interested in whether an intervention targeting gut health (supplemental fiber for 9 weeks total) will improve vascular health in individuals with obesity. Additionally, the investigators are interested in if this response differs based on whether individuals with obesity have very few heart disease risk factors or several heart disease risk factors.