It’s something that lots of us do without thinking: when we need to heat up leftovers for a quick lunchtime meal in the office or when we get home, we just bung them in the microwave still in the plastic container they were stored in. But a world-leading scientist has warned emphatically that you should “never, never” put plastic in the microwave as they could lead to serious health problems.
Dr Shanna Swan is a world-leading epidemiologist whose work has long been featured by leading magazines and newspapers around the world. She was appearing on the Huberman Lab podcast, run by Andrew Huberman, another world-famous scientist.
Dr Huberman asked her: “Is it true that microwave-safe just means that the plastic won’t melt in the microwave?”
But before he had even finished the question, Dr Swan interrupted to say: “Never, never put plastic in a microwave.”
She went on: “Here’s the story: the BPA, phthalates, plasticisers are added to the plastic but they’re not chemically bound to it.”
Phthaltes are a class of chemicals which act as binding agents and also make plastics flexible. In recent years, researchers have linked them to asthma, ADHD, breast cancer, obesity, type 2 diabetes, low IQ, neurodevelopmental issues, behavioral issues, autism spectrum disorders, altered reproductive development and male fertility issues.
BPA is an industrial chemical used in plastic manufacturing which is added to many commercial products, including food containers, baby bottles and plastic water bottles. It too has been linked to several adverse health effects including cancer, infertility, endometriosis, obesity, heart disease and type 2 diabetes. It has been used since the 1960s for food packaging but there are concerns about its ability to leach into food and drinks.
Exposure to BPA is so widespread that Healthline reports that “research suggests most people over the age of six have measurable amounts of BPA in their urine”. It adds: “One study found that about 85% of Korean children under two years old had detectable levels of BPA in their urine.”
A plasticiser is a chemical additive that makes plastics and other materials softer and more flexible.
Dr Swan said: “So if you put anything in a container that has these chemicals in it and then put it in a hot environment, they will come out of the plastic and go into the food. So if you put it in a microwave or you put your bottle in the car and the sun comes in and warms up the bottle then the stuff goes into your water. You don’t want to mix these chemicals and your food but, if you do, the worst thing is to do it in a heated environment.”