icon-arrow-down icon icon-arrow-fill-down icon icon-arrow-next icon icon-arrow-prev icon icon-tag-close icon
Are microwave ovens safe?
Q: We use our microwave all the time to cook and heat up food, but someone suggested that there are health concerns about microwaves. Is this true?
Amy Provo
A: Amy, it’s true that microwave ovens are a modern convenience that can save time in cooking and reheating food. But it’s also important to pay attention to the possible health risks of microwave ovens.

Microwave ovens use microwave radiation, a form of electromagnetic radiation. Microwaves are convenient for cooking because they pass through glass, paper and plastic and are absorbed by food, producing heat that can reheat or cook the food. You don’t need to be concerned that this makes the food radioactive.

Also, there are no signs that microwave cooking reduces the nutritional value of food any more than stovetop or traditional oven cooking. In fact, some experts believe that microwave cooking may preserve more of the vitamins in food because it cooks food more quickly, leaving less time for the heat to break down the vitamins, and uses less water, which can leach out the vitamins.

The main concerns about microwave cooking are the following:

1. Physical exposure to microwave radiation: It’s generally believed that the correct use of microwave ovens in good repair does not expose people to unsafe levels of microwave radiation. However, unsafe exposure to such radiation can cause burns, cataracts and male sterility. General safety recommendations are to not use a microwave if the door is broken, not lean against one while it’s running and not let a young child use a microwave unsupervised.

2. Cooking with dangerous containers: It’s important to use only cookware labeled for use in microwave ovens:
  • Burns from metal: Never use containers with metal in the microwave since they can overheat and spark, causing burns and fires.

  • Possible toxics in plastics: Don’t use non-microwave approved plastic storage containers and don’t reuse microwaveable containers designed for one-time use. Microwave cooking can cause them to warp, melt and possibly release chemicals into the food. Also, cover the containers only with microwave-approved covers, plastic wrap or paper, and don’t let plastic wrap covers touch the food.

3. Uneven heating of food: Microwave ovens can heat liquid and solid foods unevenly, leaving some cooler parts and some scalding hot spots. There are two dangers in this:
  • Hot spots: Babies who have been given formula heated in a microwave oven have gotten bad mouth burns. For this reason, it is recommended not to heat milk for a baby in a microwave.

  • Cold spots: Cooking meat in a microwave can lead to uncooked spots in which bacteria can survive. This can lead to food-borne illness. To thoroughly cook meat, it’s safer to use traditional methods.

For more information, see the U.S. Food and Drug Administration, centre for Devices and Radiological Health website www.fda.gov/cdrh/consumer/microwave.html.

Karen Sokal-Gutierrez M.D., M.P.H. Pediatrician