Could Exposure to Plastics Today Affect Your Great Grandchildren?
If you are having a difficult time becoming pregnant, some very common household plastics may be playing a role. Three plastics (phthalates) were found to increase time to pregnancy by 20% in couples in which the male partners had high urinary concentrations of monomethyl phthalate, monobenzyl phthalate and monobutyl phthalate. This study, from the National Institutes of Health (NIH) and other institutions, included 501 couples who were recruited to participate in the Longitudinal Investigation of Fertility and the Environment (LIFE) study. Published in Fertility and Sterility in February 2014, the authors looked at levels of Bisphenol A (BPA) and 14 different plastic-related compounds as well as the time it took for couples to achieve a conception. “Our study shows that exposure to certain phthalates can reduce the chance of conception for otherwise healthy couples,” said the study’s first author, Germaine M. Buck Louis, PhD of the National Institute of Child Health and Human Development.
Phthalates are actually “plasticizers,” substances added to plastics to increase their flexibility, transparency and durability. Phthalates are everywhere: adhesives and glues, electronics, building materials, personal hygiene products, medical devices, detergents, packaging, children's toys, waxes, paints, printing inks, medications, food products, and textiles.
BPA is a chemical used to make certain plastics such as the ubiquitous polycarbonate plastic. Clear and nearly shatter-proof, polycarbonate is found in baby bottles and water bottles, sports equipment, medical and dental devices, dental fillings and sealants, CDs and DVDs, eyeglass lenses and household electronics.
Phthalates have hormonal actions and are known as “endocrine disruptors.” Plastics can counter androgens (“male” hormones such as testosterone) and levels of phthalates in infertile men are related to low androgen levels, low sperm counts, abnormal sperm forms and increased sperm DNA damage.
It could be that phthalate levels in men adversely affect reproductive success by epigenetic effects (markers that turn genes on and off but do not affect DNA). If DNA is the hardware, epigenetic factors are the software that tell genes what to do and when. A new study underway at the University of Massachusetts Amherst led by environmental health researcher Richard Pilsner seeks to understand if epigenetic modifications may be secondary to exposure to plastics. Epigenetic factors can be inherited on top of genetic (DNA) inheritance and are shaped by environmental exposure such as smoking, air pollution and toxins. Such environmentally-induced epigenetic modifications could be manifested for generations to come so it may be possible that those plastic water bottles today could affect one’s great grandchildren someday.