13. Role of Heavy Metals in Metabolic Disorders

The majority of the heavy metals are considered toxic to the human beings by interfering with the normal functions that are taking place in the human body by disrupting metabolic processes and their exposure may be due to natural or anthropogenic sources. Heavy metals act as endocrine-disrupting chemicals (EDCs) by disrupting the mechanism of action of endogenous substances. Heavy metals such as cadmium and arsenic have a negative impact on some enzymes that are involved in carbohydrates and lipids metabolism and lead to an abnormal level of glucose and lipid, cholesterol, and triglycerides. This is responsible for inducing the pathogenesis associated with diabetes mellitus and insulin resistance. These metals are also responsible to induce reactive oxygen species and suppress antioxidant defense mechanism. The stress-induced by oxidation is highly linked with metabolic syndrome. These conditions lead to a risk of diabetes-associated cardiovascular diseases. While on the other side, some of the heavy metals notably zinc which is considered as an essential nutrient, play its significant role in metabolic disorders by suppressing oxidant effect, reducing obesity and lipogenesis. In this chapter, we have briefly overviewed the role of heavy metals that act as EDCs in metabolic disorder via interfering various transcriptional and metabolic pathways while the other heavy metals which have a beneficial role in the amelioration of metabolic disorders.