The common phthalate chemical DEHP has been linked with a number of serious health problems (including obesity and diabetes discovered in two U.S. National Institute of Health (NIH) studies). Just as problematic, DEHP has also been associated with human reproductive abnormalities and scientists at Harvard Medical School and the New York State Department of Health have just discovered how: the chemical likely does its damage at the molecular level. More specifically, the new scientific study has revealed the process by which the common phthalate chemical DEHP (used to make plastic flexible) triggers birth defects, miscarriage and male infertility. The study results revealed that DEHP causes molecular damage by interfering with proper cell division during egg formation. This leads to excessive DNA breakage and alters chromosome appearance.
For years, scientists have linked exposure to DEHP, short for BIS(2-ethylhexyl) phthalate — a chemical added to many plastics to make them flexible — to increased risk of health problems, including reproductive abnormalities such as birth defects and male infertility.
U.S. federal and state agencies responded to the scientific findings by passing laws limiting (but not outright banning) the percentage of DEHP and other phthalates in children’s toys, food packaging, drinking water and other items, although DEHP can still be found in everyday products ranging from medical devices, to rain gear, to shampoo, not to mention processed food packaging containers.
Study results overview
In the new study, the research team discovered that DEHP causes trouble in two ways.
First, DEHP causes an excessive number of double-strand DNA breaks as the worms’ “parental” genetic material recombined in their eggs. The chemical appears to do this by altering chromosome length and relaxing the normally tightly wound structure of chromatin, exposing more DNA to potential breakage.
DEHP then compounds the problem by interfering with the system that’s supposed to shut down excess breakage during meiosis.
The results: breaks aren’t properly repaired during meiosis, chromosomes have abnormal morphology, eggs contain the wrong number of chromosomes and embryos are less viable, the team found.
Some people are luckier than others when exposed to this phthalate chemical
“Not everyone metabolizes DEHP in the same way. The route and duration of exposure, a person’s age and diet, these are just some of the factors that can result in some people being more affected by low-level exposure to a given chemical than other people.”
-Dr. Monica Colaiácovo, researcher, professor of genetics, Blavatnik Institute at Harvard Medical School
What does this discovery mean in the real world?
The findings could have implications for those who are (1) pregnant or of reproductive age, (2) for regulation of DEHP and other phthalates and (3) for the ongoing development of “green chemicals” intended to replace phthalates.
For consumers it requires being educated and aware of what is in the products we bring into our homes–and this is especially true for those consumers who are pregnant or want the option to have children in the future or who have risk factors for obesity or diabetes. Read the labels of all products carefully and just forget about anything that lists the phthalate ‘DEHP’ (or any phthalates, for that matter) on the label. Skip the clothing that advertises it is water/rain resistant, wrinkle resistant, super stretchy or stain resistant (it’s not magic–they use some pretty potent chemicals to make that stuff happen), plastic shower curtains and liners, vinyl flooring, synthetic fragrances in commercial room deodorizers, dryer sheets, laundry detergent, and so on, and of course never ever microwave food in plastic containers. And most of all, lay off the processed food at the grocery store and fast food restaurants as phthalates frequently make an appearance in plastic food bags and other food containers which can leach into the food.
Other study findings on DEHP and Phthalates in general
Journal Reference: Luciann Cuenca, Nara Shin, Laura I. Lascarez-Lagunas, Marina Martinez-Garcia, Saravanapriah Nadarajan, Rajendiran Karthikraj, Kurunthachalam Kannan, Mónica P. Colaiácovo. Environmentally-relevant exposure to diethylhexyl phthalate (DEHP) alters regulation of double-strand break formation and crossover designation leading to germline dysfunction in Caenorhabditis elegans. PLOS Genetics, 2020; 16 (1): e1008529 DOI: 10.1371/journal.pgen.1008529