Over the years researchers have found traces of the chemical in both humans and the environment. Some scientists have said the chemical can adversely affect the human reproductive process.
Now, in three studies, researchers say they have found other BPA-related health issues.
A study at the University of Illinois Chicago (UIC) has, for the first time, linked BPA to prostate problems in men. Researchers say the endocrine-disrupting chemical appears to reprogram the developing prostate in males, making it more likely to develop precancerous lesions later in life.
“By using two novel models of human prostate development involving embryonic stem cells, this study is the first to show that low doses of BPA can actually reprogram human fetal prostate tissue in a manner that raises the risk of prostate diseases as men age,” said the study’s presenting author, Esther Calderon-Gierszal, a PhD student at UIC.
Calderon-Gierszal says BPA disrupts the way the body processes hormones by mimicking the hormone estrogen. Previous research into adult prostate stem cells and animal models found that exposure to BPA increased the risk of developing prostate cancer.
Breast cancer risks
Meanwhile, researchers at Duke University say they have found that BPA appears to increase the proliferation of breast cancer cells. They report that the chemical, at levels normally found in the human blood system, could not only promote growth of an aggressive breast cancer cell but also diminish the effectiveness of treatments for the disease.
“We set out to determine whether routine exposures to common chemicals such as those in plastics, pesticides and insecticides could influence the effectiveness of breast cancer treatments,” said corresponding author Gayathri Devi, Ph.D., associate professor of surgery at Duke. “BPA was one of the top chemicals to show growth stimulatory effects in breast cancer cells.”
In their study the researcher found that among the chemicals they analyzed, BPA caused breast cancer cells to grow at a faster rate in both estrogen-receptor positive and estrogen-receptor negative breast cancer cells.
Just as disturbing, it lowered the efficacy of FDA-approved anti-cancer drugs used to treat breast cancer, notably lapatinib.
Replacing BPA with the common substitute Bisphenol S (BPS) doesn't appear to resolve health issues either. A study led by Hong-Sheng Wang, PhD, from the University of Cincinnati, found BPS may have similar toxic effects on the heart as previously reported for BPA.
While some “BPA-free” products contain no bisphenols, some contain the substitute BPS. Wang says this may pose a problem for consumers.
“There is implied safety in BPA-free products,” he said. “The thing is, the BPA analogs — and BPS is one of them — have not been tested for safety in humans.”
Wang said exposure to BPS rapidly increased the heart rate of female rats. Under some conditions it also led to arrhythmias — heart rhythm abnormalities — far greater than in the control rats that did not receive BPS.
Previous health studies of BPA have yielded mixed results. Earlier this year researchers at the University of Missouri determined that daily exposure to low levels of BPA by pregnant primates could cause fetal abnormalities in their offspring.
While U.S. regulators have been slow to rein in use of BPA, Canada and several other countries have classified it as a toxin.