Prevention and Treatment of Obesity-Related Diseases by Diet and Medicinal Plants

Obesity increases the risk for many pathological processes including type 2 diabetes, hypertension, hyperlipidemia, cardiovascular diseases, and certain types of cancer. Thus, obesity mitigation strategies should take into account these secondary pathologies in addition to promoting weight loss. Progress in biological and particularly in biochemical studies with respect to adipocytes in recent years has gradually clarified that the dysregulation of adipose tissue expansion accompanied by hyperplasia (increase in the total number) and hypertrophy (increase in the size) of adipocytes causes obesity. Adipocytes are well recognized as endocrine secretory cells as well as fat storage cells, which produce biologically active molecules such as hormones, cytokines, and other factors. These molecules, collectively called adipocytokines (recently often called adipokine), are involved in regulating adipocyte functions and metabolism through a network of endocrine, paracrine, and autocrine signals and thus modulate adipocyte biology. Adipocytokines include tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), plasminogen activator inhibitor-1 (PAI-1), angiotensinogen, tissue factor, transforming growth factor-β (TGF-β), leptin, adiponectin, resistin, and certain chemokines such as monocyte chemoattractant protein-1 (MCP-1). Most adipocytokines are increasingly produced with increasing adiposity and are closely associated with obesity-related pathologies (e.g., metabolic syndrome, diabetes, and cardiovascular diseases). In this chapter, we will focus on prevention and treatment of obesity-related diseases by diets and medicinal plants.