Plastic food packaging contains chemicals that disrupt the endocrine system — and that can leach into food, a new study has found.
Once there, these chemicals can mimic — or disrupt — the effects of the hormones estrogen and testosterone on the body, according to the study published Tuesday in Environmental Science & Technology.
Other chemicals discovered in the plastic packaging bind to chemical receptors that control how cells use energy, possibly leading to metabolic disorders.
The scientists analyzed 36 types of plastic food and drink packaging across five countries with high usage of single-use plastic: the U.S. U.K., Germany, South Korea and Norway.
These ranged from Ziploc-style bags and yogurt containers to hydration bladders and chewing gum containers.
Not all plastics had equal impacts on the nuclei of cells that researchers exposed to them.
Researchers found the most potent effects from extracts of polyurethane (PUR), polyvinyl chloride (PVC) and low-density polyethylene (LDPE).
LDPE is a common polymer used in Ziploc-style bags, among other things, and PVC is the main component in cling wrap. Polyurethane is a common element in food packaging — wrapped around cheeses for example — and some water bladders for hiking packs.
They found less response in cell nuclei exposed to chemicals such as high-density polypropylene (HDPE), polyethylene (PET) and polypropylene (PP).
These are chemicals found in milk bottles, to-go cups and yogurt containers.
But that does not mean that those plastic compounds are safe, the researchers cautioned.
“We cannot conclude that a particular polymer type is free of toxic chemicals,” they wrote — because “samples of each polymer activated most receptors” in the cells they exposed to the chemicals.
The researchers raised a particular note of caution over the number of distinct chemicals found in each plastic. Most contained hundreds to a few thousand, but on the high end, one American-made cling wrap contained nearly 9,000.
That high number is significant because the process of discovering which compounds are toxic is so painstaking — let alone what plastic compounds do in combination with each other, or as they degrade.
That means that one way to make plastic safer is to make it simpler, researchers found.
“Chemically less complex plastic products induced lower toxicity,” they wrote. “By the use of fewer and better-characterized chemicals, the safety of plastic products can be significantly improved.”