New research from the University of California San Diego School of Medicine may have discovered that the molecule formed when Bisphenol A (BPA) breaks down inside the body is causing health problems. Bisphenol A is a chemical used in plastics that human beings routinely ingest. When the chemical is broken down inside the body, a molecule called MBP binds to the estrogen receptor in human cells much more strongly than BPA.
According to the news release, “more than 90 percent of all Americans are believed to carry varying levels of BPA exposure.” Many studies have shown associations between BPA exposure and cancer, neurological disorders including problems in early childhood development as well as memory and learning, heart disease, and reduction in the efficacy of chemotherapy. In April, the FDA ruled against a proposed BPA ban, saying they need to conduct more research on the possible problems with the chemical.
The scientists at the University modeled BPA, MBP, and estradiol, one of the body’s three main estrogens, in three dimensional form. They found that MBP binds to estrogen receptors, which disrupts the body’s endocrine, or hormonal, system. The MBP molecule closely resembles the estradiol molecule and is long enough to mimic estradiol more strongly than the BPA molecule.
In other words, Dr. Michael Baker, one of the authors of the study, said “MPB is basically grabbing onto the estrogen receptor with two hands compared to just one hand for BPA. Two contact points makes a much stronger connection.” The study’s authors state that research points need to measure MBP levels in urine and blood of patients who may have BPA health effects.
This study could have further ramifications. MBP could be used as a template to develop “a new class of chemicals that could bind to the estrogen receptor with high affinity.” Those chemicals could help control the growth of estrogen-dependent tumors in the future.