Is microwaving food in plastic really harmful to my health?

July 19, 2017 | by Samir Undevia, MD

If your fridge is anything like ours, you’ll find last night’s dinner in a plastic container, Ziploc bag or on a plate wrapped in plastic. Rule number one of re-warming food has always been to avoid reheating in plastic, but is warming food in plastic really bad for our health or is it all a hoax?

Over the past several years, the Food and Drug Administration (FDA) has been researching whether two chemicals found in plastic, bisphenol-A (BPA) and phthalates, seep into our food when warmed in the microwave and increase cancer risk. Both BPA and phthalates help make plastic the product that it is. BPA is the chemical used to make polycarbonate, or the plastic material that stores your food, while the chemical phthalates helps make the plastic flexible.

BPA enters our body mainly through food and beverages that have been in contact with polycarbonate. Items like certain water bottles, infant bottles, compact discs, and impact-resistant safety equipment contain BPA.

Exposure to BPA and phthalates is a concern because of possible health effects on the brain, behavior and prostate gland. Because of this, many products have tried to remove BPA entirely.

Recent studies have determined that low levels of exposure to BPA is safe for our bodies and that trace amounts of the chemical that enter the body (whether in an adult or child) are rapidly metabolized and eliminated.

Still, if we can limit our exposure to BPA and its potentially toxic effects, we should. When warming or cooking in the microwave, you can reduce your exposure to chemicals by:

  • Transferring food to glass or ceramic containers labeled for use in a microwave oven.
  • Not letting plastic wrap touch food during microwaving in case it melts. Wax paper, parchment paper, white paper towels or a domed container that fits over a plate or bowl are better alternatives.
  • Avoiding microwaving takeout containers (unless they are labeled microwave safe,) water bottles, and plastic tubs or jars made to hold margarine, yogurt, whipped topping, and foods such as cream cheese, mayonnaise and mustard.
  • Discarding old, scratched or cracked containers. Containers that have been microwaved many times may leach out more plasticizers.
  • Abstaining from microwaving plastic storage bags or plastic bags from the grocery store.
  • Venting the container before microwaving food by leaving the lid ajar or lifting the edge of the cover.

You can also try to be BPA-free by: 

  • Carrying your own glass, steel or ceramic water bottle filled with filtered tap water.
  • Reducing how much canned food you eat and how much canned formula your baby uses.
  • Using baby bottles with labels that say “BPA free."
  • Avoiding handling carbonless copy cash register receipts. If you get a carbonless receipt, don't recycle it. Recycling receipts with BPA in them can spread the BPA to other products made with recycled paper, including napkins and toilet paper.
  • Looking closely at plastics with a number 7 recycling symbol on the bottom. If the plastic doesn't also say "PLA" or have a leaf symbol on it, it may contain BPA. Learn more about plastic recycling symbols.

If you are concerned about heating or re-heating plastic, it is always safe to transfer your food to a microwave-safe plate.

What are your tips for cooking safely? Tell us in the below comments.

Read more cancer urban legends.

Learn about cancer care at Edward-Elmhurst Health.

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