Abstract
Bisphenol A is an organic compound that serves as a building block of polycarbonate plastics and epoxy resins. Being the world's highest-volume chemicals in use today in the form of medical devices, water and infant bottles, food cans, kitchen utensils, water supply pipes, compact devices, etc., this compound—after gaining an access to the body of an individual by way of leaching into food and water supplies—acts as an obesogen and disrupts the body weight regulation by either promoting adipogenesis or triggering the differentiation of fibroblasts into adipocytes. The other adverse effects of bisphenol A include insulin resistance, adipocyte differentiation or aromatase-mediated transformation of androgen into estrogen, cardiovascular diseases, liver function abnormalities, alterations in the circulating thyroid hormone levels, association with diabetes and carcinogenic effect. Its other aspects on health individually as well as in combination with other chemicals are worth mentioning.
TopIntroduction
The plastic monomer bisphenol A is one of the highest volume chemicals produced worldwide, with over 6 billion pounds produced each year and over 100 tons released into the atmosphere by yearly production. Humans are widely exposed to bisphenol A and animal studies have linked bisphenol A to obesity (Golub, et al., 2010; Newbold, 2010; Rubin, 2011). Emerging evidence linking the worldwide obesity epidemic to increased exposures to environmental endocrine disruptors, collectively called ‘‘environmental obesogens’’ (Heindel, 2003; Wang and Lobsttein, 2006; Newbold, 2008; Heindel and Vom, 2009), one such important potential obesogen is bisphenol A. Although it was first recognized in the 1930’s as a potential synthetic estrogen (Dodds and Lawson, 1938), bisphenol A is contained in a variety of consumer products from baby bottles, plastic containers, and the resin lining of cans for food and beverages, to dental sealants (National Toxicology Program USDOHAHS, 2008). Bisphenol A was detected in about 93%−100% of children and adolescents in Northern America, some European nations, Egypt, Australia, and Asian countries (Dodds and Lawson, 1938; Newbold, 2007; National Toxicology Program USDOHAHS, 2008; Heindel and Vom, 2009; Golub et al., 2010; Newbold, 2010; Rubin, 2011). In Thailand Bisphenol A was detected in 52.8% of adults in serum samples (Calafat et al., 2008).
In recent decades, both developing countries such as China as well as developed countries have witnessed an alarming increase in the prevalence of obesity (Chen, 2008; et al., 2008; Shan et al., 2010). The most troubling aspect of this increase is the acceleration in the prevalence of obesity and overweight among children. The prevalence of obesity in U.S. children is close to 20% (Barlow, 2007; Kosti and Panagiotakos, 2006; Wang and Lobsttein, 2006). This is especially alarming given the well-known consequences of overweight and obesity which include type 2 diabetes, hyperinsulinemia, insulin resistance, coronary heart disease, hypertension, stroke, and liver and kidney diseases among many other adverse health effects. Bisphenol A could both accelerate girls’ pubertal development and weight gain during this period. The acceleration of growth by Bisphenol A may impact both weight and height, leading to a slightly weaker bisphenol A effect on Body Mass Index measurement. It has been hypothesized that human exposure to Bisphenol A in the early stage of development could also lead to the onset of obesity and other metabolic syndrome (Rubin et al., 2001; Somm et al., 2009).
Key Terms in this Chapter
Thermoplastic: Plastic substance formed by heating and harden by cooling, able to repeat the process.
Bisphenol A: An organic synthetic compound having chemical formula of 2,2-bis(4- hydroxyphenyl) propane. It is a colourless solid that is soluble in organic solvents but poorly soluble in water. It is widely known for its tendency to leach from those products which has made it a subject of public health and environmental concern.
Bioaccumulation: The accumulation of toxic substances in various tissue or organ of the living organism.
Diabetes Mellitus: It is a disorder of carbohydrate metabolism in which there is impaired insulin secretion and/or insulin resistance leading to high blood sugar level (Hyperglycaemia).
Polycarbonate: A group of thermoplastic polymers containing carbonate groups in their chemical structures. Compound discs, riot shields, vandal proof glazing, baby feeding bottles, electric components, safety helmets and headlamp lenses etc. are all typical applications for polycarbonates.
Epoxy Resins: Also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. These low molecular substance normally contain at least two epoxide groups- sometimes referred to as a glycidyl or oxirane group.
Obesogen: A foreign chemical compound that inappropriately disrupts normal development and balance of lipid metabolism. Obesogens cause weight gain by altering lipid homeostasis to promote adipogenesis and lipid accumulation.
Insulin: It is a hormone secreted by the beta cells of pancreatic islets whose role in the body is to trigger cells to take up glucose so that the cells can use this energy yielding sugar.
Obesity: Abnormal or excessive accumulation of fat in the body that presents a risk to health.
Plastic: A synthetic material made by a human that easily shaped or molded.