Hear the word “microwave,” and you’re more likely to think of that miracle box in your kitchen than the radiation for which it’s named.
After all, microwaves heat your food through, well, microwaves. A form of electromagnetic radiation, microwaves have three characteristics that make them so darn good at zapping your leftovers, explains Dana Hunnes, adjunct assistant professor of community health sciences at the UCLA Fielding School of Public Health.
- They are reflected by metal. (That’s why you should never put metal in your microwave.)
- They pass through glass, paper, plastic and similar materials.
- They are absorbed by foods.
“The latter is why microwaves work so well at cooking foods quickly. They cause water molecules in the food to vibrate – rapidly,” Hunnes explains. “This vibration creates energy, producing heat that cooks the food. This is why foods that are high in water content, such as fresh fruits and vegetables, cook quickly. This heat is absorbed by the food.”
Is Your Microwave Really Just a Cancer Box?
Fortunately for time-starved schedules, research suggests that nuking food does not increase cancer risk. That’s largely because, no, you aren’t actually “nuking” anything.
“The type of radiation typically associated with cancers and with ‘nuclear’ reactions are gamma, neutron and ionizing radiation. This type of radiation can change a cell’s DNA and predispose a person to cancer,” Hunnes says. (FYI, we are constantly exposed to small doses of background ionizing radiation from natural sources, like soil, cosmic rays and even the foods we eat. Seriously, bananas, Brazil nuts, and kidney beans produce ionizing radiation – but their nutrients can actually help prevent cancer.)
“Microwaves and the radiation from microwave ovens, however, are non-ionizing radiation. This type of radiation can move things around in a cell – hence the heating of food – but cannot chemically change cells or DNA in the food you eat,” Hunnes says.
That said, while federal U.S. standards set strict limits on how much radiation can leak from a microwave, according to the American Cancer Society, the farther you stand from a microwave, the less radiation you’re exposed to. “Standing 20 inches away from a running microwave results in a 100-fold drop in radiation exposure,” she explains. So no smooshing your face against the glass while you wait for your food to cook.
Are Microwaved Foods Nutritious?
It depends exactly what you are comparing microwaved foods to, but in general, it’s actually better to heat food in the microwave versus steaming, boiling or baking it.
“Much of this has to do with the fact that microwaves heat foods so quickly. Vitamin C, a nutrient that is frequently lost in cooking, has been found to be well-preserved when microwaving,” Hunnes says. “In general, cooking methods that best retain nutrients are those that cook quickly – heating the food in the shortest amount of time and using as little liquid as possible.”
Why so little liquid? Because when you plop foods in water and then crank up the heat, their nutrients can leach out into the water – which goes right down the drain, explains Leslie Bernstein, a professor in the department of population sciences at the City of Hope’s Beckman Research Institute.
“The nutritional effects of microwave cooking on protein, lipid and minerals seem to be minimal. For microwave reheating of foods, nutrients like thiamin, riboflavin pyridoxine, folacin and ascorbic acid are retained,” Bernstein says. “Furthermore, microwave-cooked bacon actually has lower levels of nitrosamines, potentially carcinogenic compounds, than conventionally cooked bacon.”
That’s it. We’re off to microwave some bacon. Or, better yet, broccoli.