Polyphenols in Obesity and Metabolic Syndrome

Overweight and obesity are considered a world pandemic of the 21st century. Obesity is a complex multifactorial disease influenced by lifestyle, behavioral, environmental, and genetic factors. Metabolic syndrome (MetS) is a cluster of associated metabolic disturbances which tend to coexist, commonly represented by the combination of obesity (especially abdominal obesity), hyperglycemia, dyslipidemia, and hypertension. MetS is associated with an increased risk of cardiovascular diseases (CVDs), characterized by abnormal cytokine production that leads to endothelial dysfunction. Oxidative stress is associated with CVDs and their related risk factors, such as obesity and type 2 diabetes, and with other chronic degenerative processes such as cancer and other aging-related diseases. Epidemiological evidence indicates that polyphenol-rich diets, such as the Mediterranean diet, are associated with antioxidant, antiinflammatory, and antiobesity effects and with the reduction of risk factors for MetS and CVDs. Polyphenols can be found in nature, mainly in plants and vegetables. Probably the best known beneficial effect of polyphenols is their antioxidant capacity, which is capable of reducing reactive oxygen species and various organic substrates and minerals. In this chapter we explain the nature of polyphenols and their classification, and elucidate their potential mechanism of action and the current evidence in regard to obesity and MetS.