No, Microwaves Are Not Bad For You

Microwaving doesn't destroy all the nutrients in your food or make it radioactive.

Jan 16 2019, 9:43pm

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Welcome to Wellness Lies, our list of the most pervasive misfires in the effort to feel and look better. We asked the experts and consulted the best science on all the questions you have about each of these wellness fads. Read the whole list and share with your most misinformed friends and family members.

If there’s one health myth that just won’t die, it’s that using a microwave oven is dangerous and cancer-causing. (That sure adds an element of paranoia to reheating last night’s pizza.)

The two main criticisms of using microwaves go like this: that the convenient device a) produces radiation in your food and outside of the appliance, thereby upping your cancer risk, and/or b) zaps all the nutrients out of your food.

Lucky for you, neither of those things are true. We could stop there, but let’s expand on each one.

First, let’s define microwave radiation. It’s a form of electromagnetic radiation, which also includes things like the waves from lightbulbs, radios, and X-rays, according to the Food & Drug Administration (FDA). Of course, they’re not all the same—they exist on a spectrum from low to high frequency.

Over on the left, the non-harmful side, is the radiation coming from a regular lightbulb in your house, through a radio, or—you guessed it—your microwave. This low-frequency radiation is non-ionizing, meaning it can’t change molecular structures or damage cells, the FDA says. On the right, more harmful forms of radiation are ultraviolet radiation (aka from the sun) and X-rays. These high-frequency types are ionizing and can damage cells. This is why you generally wear protective gear when getting an X-ray, like that big, heavy smock at the dentist. You also wear a broad-spectrum sunscreen before spending time outside, or at least you know you should.

So, you’re saying microwaves don’t cause cancer?

No, they don’t. Some people think that microwaves cook food by a sinister force, but it works similar to other methods of cooking. “Microwaving is a method by which heat is delivered to food,” says Aaron E. Carroll, a professor of pediatrics at the Indiana University School of Medicine and author of Don’t Cross Your Eyes…They’ll Get Stuck That Way!: And Other Health Myths Debunked. (Your oven or stove also transfers heat to food.) “People get all panicked about the word radiation, but microwaves use this electromagnetic radiation to ‘excite’ water molecules in the food, which heats it up,” he explains. Specifically, microwaves cause water molecules to vibrate and that produces heat. The American Cancer Society (ACS) goes further to calm your nerves: “Microwaves…do not make food radioactive.”

That said, experts don’t recommend heating food in plastic containers since plastic can leach into your dinner. Use plates and bowls made from glass or microwave-safe ceramic.

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As for standing near the microwave waiting for your food to cook, yeah, a small amount of radiation essentially leaks from the appliance, but you don’t need to don protective gear. “The radiation you’d be exposed to with microwave cooking is negligible,” says Francisco Diez-Gonzalez, professor and director of the Center for Food Safety at the University of Georgia.

The ACS notes that these are well-controlled devices: “In the US, federal standards limit the amount of radiation that can leak from a microwave oven to a level far below what would harm people.” Microwaves only produce waves when they’re turned on, and the FDA also requires that they stop making waves the moment the door latch is released. (If someone in your family had a pacemaker decades ago, they may have been told to leave the room when the microwave was on because of a risk of electrical interference, but the FDA says today’s pacemakers shield against these waves—and those of other devices like electric shavers and car ignition systems.)

Still worried? Maybe don’t sit with your face pressed right up against the door. (Do you actually do this?) The FDA says there’s about 1/100th of the microwaves 20 inches from the unit compared to two inches away, even though the amount at two inches is far below the level known to harm people.

But don’t microwaves destroy the nutrients in my food?

Another popular argument against microwaving is that it destroys the vitamins in your food. Here’s the thing: heating in any way will degrade some nutrients (like vitamin C) but make other nutrients more bioavailable to your body (like the antioxidant lycopene in tomatoes). That makes a perfect case for including both raw and cooked foods in your diet.

What’s more, in a 2009 study in the Journal of Food Science that analyzed the effects on antioxidants in vegetables from various cooking methods—including boiling, microwaving, pressure cooking, griddling, frying, and baking—researchers found that microwaving was among the techniques that lead to the lowest nutrient losses. And it depends on the food, too: A 2010 study found that microwaving Brussels sprouts increased content of antioxidant plant compounds called polyphenols by 90 percent, but reduced polyphenols by 67 percent in broccoli.

A meta-analysis in 2018 in Critical Reviews in Food Science and Nutrition found that it was boiling, baking, and frying that had the biggest impact on lowering polyphenol content and antioxidant activity in food. Microwaving landed somewhere in the middle. Steaming won out, so if nutrients are your biggest concern, you could always steam your food from now on.

Ultimately, there are a whole lot of factors that go into whether or not nutrients degrade or increase while cooking, including technique, time, how much water is used, what food it is, and what the heck nutrient you’re even talking about.

You say microwaves are safe but, uh, don’t some people get hurt from using them?

Yeah, but it’s the old “you’re using it wrong” argument. “People do irrational things, such as putting metal items inside microwaves—clearly things that are not recommended,” says Diez-Gonzalez. Remember, metal containers and aluminum foil are not compatible with microwaves. Plastics can be iffy, too, so check to make sure your container is labeled “microwave safe.” Dry foods (like uncooked rice) are another no-no, as they can overheat and catch fire, he says.

Another not-great practice: cooking raw chicken or a raw roast in the microwave. “There’s been multiple instances in which raw poultry has caused foodborne illnesses. One of the limitations of microwaves is that the heating isn’t uniform,” Diez-Gonzalez says. That means it leaves uncooked “micropockets” inside meat that allow bacteria to survive.

And finally, most injuries come from burns because the food or container was too hot to touch, Carroll says. Use a towel or an oven mitt when taking it out.

Bottom line, according to Diez-Gonzalez: “Microwaving is safe. There’s no evidence that microwaves—after more than 50 years of using them routinely—cause any health issues if used according to the manufacturer’s recommendation.”

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