Safe Levels of BPA, Other Endocrine Disruptors, Should be Re-Evaluated: Study

New research suggests that humans and rat testes respond differently to endocrine disrupting chemicals, such as the controversial bisphenol A (BPA) used in many plastic bottles and containers, prompting researchers to reconsider prior safety conclusions drawn from animal studies. 

In a study published in a special April issue of the medical journal Reproduction, which is dedicated to research on endocrine disrupting chemicals (EDs), researchers indicate that there needs to be a reevaluation of what levels of exposure to endocrine disrupting chemicals are safe for humans.

A team of researchers led by Professor Rene Habert from the French Institute of Health and Medical Research (INSERM), and others from the Atomic Energy Commission (CEA) and University of Paris-Diderot, compared the effects of six different EDs on the function of human, rat and mouse fetal testicular tissue during different stages of development.

Researchers tested the tissue with bisphenol A (BPA), pesticides, flame retardants and other chemicals like cadmium and depleted uranium. They simulated normal testicular development in each species using an in vitro culture system called FeTA. The system, considered very reliable, studies cell development across species more effectively than in vivo methods, guarding against cross contamination.

The only limitations FeTA testing offers is in the long-term testing of the development of the testes. FeTA can only be maintained for up to 10 days, depending on the species.

Researchers found two-thirds of the tests in human, rat and mouse tissue responded differently to the different endocrine disrupting chemicals. Human tissues proved to be 100 times more susceptible to some of the chemical compounds, including the ubiquitous BPA.

Different effects were seen in each type of tissue after being exposed to different compounds.

Researchers say the results of the study could lead to a complete reevaluation of the acceptable daily intake for many endocrine disrupting chemicals, a move called for numerous times by many critics.

The study was prompted by a decrease in male sperm counts and an increase in testicular cancer over the past few decades. Critics say these effects and other disorders including an increase in the occurrence of undescended testicles are attributed to the prevalence of endocrine disrupting chemicals in the environment.

At minimum, researchers say the findings put into question the relevancy of animal data in assessing the risk of chemicals in humans.

Endocrine Disruptor Health Concerns

Endocrine disruptors are compounds which interfere with animal hormones. Chemicals like BPA and other phthalates can cause a slew of problems ranging from developmental problems with the reproductive system causing infertility in women and interfering with the proper development and formation of the human brain.

Research has also shown a link between fetal exposure to BPA and an increased risk of prostate cancer. Yet other studies warn exposure to BPA even at low levels may pose serious risks.

A study published late last year found even low levels of BPA caused adverse effects. In fact, negative effects seen at much lower levels than scientists originally thought would be harmful.

Yet other side effects linked to BPA exposure include a heightened risk of developing breast cancer and other cancers.