New research suggests that exposure to the chemical tributylin (TBT) — found in shower curtains, carpeting, vinyl, and paints — is linked to obesity not only in offspring but in subsequent generations.
Exposing pregnant mice to low doses of TBT — generally used as an antifungal agent — can lead to obesity for multiple generations without subsequent exposure. In other words, once the pregnant mouse is exposed, her “children,” “grandchildren,” and “great-grandchildren” were all affected, regardless of whether or not they were individually exposed to TBT.
Researchers at the University of California Irvine exposed pregnant mice to low TBT concentrations, similar to those found in the environment and in humans. Researchers then observed increased body fat, liver fat, and fat-specific gene expression in liver and stem cells in the mouse “children” and subsequent generations. While the “children” were exposed the TBT as embryos, and the “grandchildren” may have been exposed as germ cells within the “children,” the “great-grandchildren” had never been exposed yet still showed symptoms of exposure.
This leads researchers to believe that the effects of TBT are transgenerational and are thought to be permanently transmitted to future generations.
“These findings demonstrate that early-life exposure to endocrine-disrupting compounds such as TBT can have permanent effects on fat accumulation, gene expression and stem cell programming without further exposure,” said study leader Professor Bruce Blumberg with the UC Irvine Departments of Developmental & Cell Biology, Pharmaceutical Sciences and Biomedical Engineering.
TBT may now be joining the ranks with BPA, another chemical substance recently found to contribute to obesity. The Inquisitr reported that a new report published in the latest issue of the Journal of the American Medical Association linked BPA to childhood obesity. The study comes after the FDA banned BPA from being used in baby bottles and is more evidence that childhood obesity may not merely come from diet and exercise.
Dr. Leonardo Trasande, a professor of pediatrics and environmental medicine at the New York University School of Medicine, stated, “Clearly poor diet and lack of physical activity contribute to increased fat mass, but the story doesn’t end there.”
Humans are exposed to TBT in a variety of ways. TBT particles are found in shower curtains, vinyl flooring, carpet fibers, polyurethane foams, mold-resistant paints, and other consumer products where it is used as an antifungal agent. As a result, noteworthy levels of TBT have been reported in house dust, which may have a particular effect on babies and young children who can spend a significant amount of time on the floor.
While TBT — much like BPA — is now largely banned for use, it is pervasive in the environment. People can also be exposed by ingesting TBT-contaminated seafood.
Blumberg categorizes TBT as an obesogen, a class of chemicals that promote obesity by increasing the number of fat cells and the storage of fat in existing cells or by altering metabolic regulation of appetite and satiety.
The TBT study appeared online in Environmental Health Perspectives, a publication of the National Institute for Environmental Health Sciences.