Food and drink cans have a thin plastic lining on the inside, so the metal does not react with the food. For decades that lining was usually an epoxy plastic made with bisphenol A (BPA), a chemical that can mimic hormones in the body.
Researchers at the Harvard School of Public Health asked 75 volunteers to eat a serving of canned vegetarian soup every day for five days, and fresh soup every day for another five days. After the canned soup week, the BPA in their urine was more than ten times higher than after the fresh soup week.
Cans have changed since 2011. In the US, the can makers' trade body said about 90% of food cans were made without BPA by 2018. The European Union banned BPA in food packaging from 20 January 2025, with extra time for some cans. Australia has no ban; Food Standards Australia New Zealand (FSANZ) says BPA levels in Australian food are low and unlikely to harm health. The newer linings, mostly acrylic and polyester, are still plastic, and far less is known about what they release.
Why it matters: even food that looks plastic-free can come in plastic. Fresh, frozen or dried food avoids the question, and dried beans and lentils usually cost less than canned ones.