The global obesity situation is worsening, especially among children: obesity rates have been increasing over the past decade and are shifting to earlier ages, reports The Washington Post.
Approximately 40% of US high school students were overweight before they started school, and the incidence has tripled worldwide since the 1970s. A total of one billion people are expected to be obese by 2030. It is closely related to high blood pressure, diabetes, heart disease, and other health problems.
The presence of chemicals in our environment is one of the main causes of obesity, scientists believe. Chemical substances, even in very low doses, disrupt the normal functioning of human metabolism, as well as the body’s work, and the ability to regulate energy consumption and expenditure.
Some of these substances, such as “obesogens,” stimulate the production of certain types of cells and adipose tissue that are associated with obesity. These chemicals are used in particular in plastic packaging, clothing, and furniture, cosmetics, food additives, herbicides, and pesticides.
“Obesogens are certainly a contributing factor to the obesity epidemic,” says Bruce Blumberg, an expert on obesity and endocrine-disrupting chemicals from the University of California, Irvine. “The difficulty is determining what fraction of obesity is related to chemical exposure.”
Traditional chemical toxicity tests often fail to detect toxins, and the effects of chemical exposure may not manifest themselves during the body’s lifetime. However, they can be transmitted through so-called epigenetic mechanisms to offspring even after several generations. An example of this is tributyltin or TBT, a chemical used in particular in wood preservatives. By exposing mice to low and supposedly safe levels of TBT, Blumberg and his colleagues found a significant increase in fat accumulation over the next three generations.
TBT and other types of obesity cause effects that interfere with the normal biochemistry of the endocrine system, which regulates energy storage and use and human eating behavior. This depends on a large number of hormones produced in the gastrointestinal tract, pancreas, and liver, as well as chemicals in the brain that can change the sensation of hunger. Mice exposed to obesity-inducing chemicals before birth show a significant change in appetite later in life and a tendency to become obese.