Obesity has become a pandemic. Worldwide obesity has more than doubled since 1980. If current trends continue, 20% of all people will be obese. Over 35% of U.S. adults and close to 17% of children are obese, which is defined as having a body mass index (BMI) of over 25.
Lifestyle choices play a huge role. Diet and activity levels are leading contributors to the development of obesity. In addition, scientific evidence is mounting that shows endocrine disrupting chemicals (EDC) may also contribute to obesity. Two terms are used to describe the role of EDCs in metabolism and obesity:
- Diabetogens are chemicals that can enter the body and kill β-cells or disrupt their function and interfere with normal energy metabolism, which can lead to diabetes.
- Obesogens are chemicals that can enter the body and disrupt normal lipid metabolism, which can lead to obesity.
Reprogramming metabolism through nutrition
Your endocrine system controls your metabolism through the hormones it produces. When your body needs nutrition, hormones spur metabolic responses like hunger that prompt you to eat.
When EDCs block connections between hormones and their receptors, they “reprogram” the parts of the endocrine system that govern metabolism, energy balance, and appetite. EDCs change the sensitivity to glucose (sugar) and the metabolism of lipids (fatty acids). All of this predisposes a person to gain weight.
Permanent changes to appetite and fat storage
EDC-related weight gain involves more than just adding a few pounds. EDCs can alter the way our bodies consume food and store energy.
To understand this process, it’s important to look at how metabolism functions at the cellular level. For example, your thyroid produces hormones that regulate the day-to-day metabolism of your body’s cells. EDCs found in pesticides, plastics, industrial waste, and fragrances can disrupt the thyroid’s normal processes thereby disrupting metabolism.
Studies have shown that certain EDCs interfere with the body’s control of appetite and increase energy storage in fat tissue such as the chemical BPA found in many consumer products from aluminum cans to water bottles. Evidence also indicates that BPA exposure in the womb can lead to obesity later in life.
Diabetes and cardiovascular disease and obesity
Weight gain is only one effect of EDCs. In rodent studies, mothers exposed to a chemical in one of the most commonly used fire retardants in the United States led to altered levels of thyroid hormone secretion. After giving birth, their pups grew up to develop not only obesity but also heart disease, early puberty, and insulin resistance.
The hormone insulin is necessary to regulate blood sugar levels and prevent diabetes. Certain EDCs impede these functions, increasing the enzymes that make glucose while reducing the ability of the pancreas to secrete insulin in response.
In recent studies, mice exposed to the chemical DDT became insulin resistant, which can ultimately lead to diabetes. In a striking note, nations where DDT is still in use such as South Africa and India have seen dramatic increases in diabetes, which may be due in part to environmental exposures.
Although DDT has been banned in many nations, other EDCs related to metabolic syndrome are still widely used. In Denmark, children exposed to PFCs—industrial chemicals found in a variety of consumer products—were more likely to show early signs of metabolic syndrome.
Because many factors contribute to obesity and related conditions in people, more research needs to be done to establish causality. That said, numerous studies have linked BPA exposure with cardiovascular disease and hypertension, and recent evidence in animals suggests that BPA may trigger irregular heartbeats.