Exploring Tannin-Probiotic Interactions on Microbial Composition and Inflammatory Outcomes in Obesity

Introduction Background Obesity is a serious, common, and expensive chronic disease, and according to a report by the Center for Disease Control and Prevention, more than 2 in 5 adults in the United States (US) live with obesity. The issue of obesity in the US is an increasing trend, as reports have shown that the prevalence of obesity among US adults aged 20 and above from 2017 to 2020 was 41.9%, rising from 30.5% in 2000. Concurrently, the prevalence of severe obesity also increased from 4.7% to 9.2%. Meaning over 100 million adults in the US are living with obesity, while more than 22 million people are living with severe obesity.

The main cause of obesity is abnormal and excessive lipid buildup in many organs and tissues, especially in the visceral or abdominal area, including white adipose tissue (WAT), which is referred to as abdominal obesity. Numerous important non-communicable diseases, such as diabetes mellitus, metabolic dysfunction-associated fatty liver disease (MAFLD), cardiovascular diseases, hypertension, and renal disorders, are significantly influenced by this type of obesity. One of the main pathogenic mechanisms in obesity has been proposed to be impaired adipogenesis, or the process of adipocyte differentiation.

Increased oxidative stress and inflammation are further characteristics of unhealthy WAT remodeling. Histological crown-like structures (CLSs) are formed when enlarged adipocytes release chemokines that attract immune cells, mainly macrophages, to encircle the adipocytes. By triggering pro-inflammatory regulators like nuclear factor-kappa B (NF-κB), which in turn boosts the production of inflammatory genes and overpowers anti-inflammatory regulators like interleukin 10 (IL10), this mechanism intensifies the hyperinflammatory state. Furthermore, reactive oxygen species (ROS)-induced oxidative stress can override antioxidant regulation, especially the nuclear factor erythroid 2-related factor 2 (NFE2L2/NRF2)-mediated expression of antioxidant genes.

Metabolic problems, such as insulin resistance, dyslipidemia, and disturbed adipogenesis, are caused by both oxidative stress and inflammation. Therefore, methods to avoid adipocyte hypertrophy, improve adipogenesis to create normal adipocytes, reverse harmful WAT remodeling, and limit oxidative stress and inflammation may be effective ways to fight obesity and metabolic syndrome.

The use of dietary intervention for obesity prevention and management has been used for many years and has been described by researchers as foundational. Consuming meals or natural products, including fruits and vegetables, that are low in energy density and high in bioactive chemicals has been suggested as a way to manage obesity and its associated issues. Edible wild fruits and vegetables from different areas are known to contain a variety of bioactive substances, including phenolics, which may have anti-inflammatory, antioxidant, and metabolic-regulating effects. Fruit extracts that contain flavonoids and polyphenols, such as quercetin, catechin, and rutin, have demonstrated positive benefits on markers of metabolic dysfunction. In animal models of obesity, they include decreases in adipocytes and macrophages, lipid buildup, visceral adipose tissue, and markers of inflammation and oxidative stress.