Cooking with a microwave oven is highly convenient, as it’s simple and incredibly fast.
However, many people believe that microwaves produce harmful radiation and damage healthy nutrients.
Therefore, you may wonder whether it’s safe to use these appliances.
This article explains whether microwave ovens affect your food quality and health.
Microwave ovens are kitchen appliances that turn electricity into electromagnetic waves called microwaves.
These waves can stimulate molecules in food, making them vibrate, spin around, and clash with each other — which turns the energy into heat.
This is similar to how your hands heat up when you rub them together.
SUMMARY Microwave ovens turn electric energy into electromagnetic waves. These waves stimulate molecules in your food to heat it up.
Microwave ovens produce electromagnetic radiation.
You may find this concerning due to radiation’s negative connotations. However, this is not the type of radiation associated with atomic bombs and nuclear disasters.
Microwave ovens produce non-ionizing radiation, which is similar to the radiation from your cell phone — though much stronger.
Keep in mind that light is also electromagnetic radiation, so clearly not all radiation is bad.
Microwave ovens have metal shields and metal screens over the window that prevent the radiation from leaving the oven, so there shouldn't be any risk of harm.
Just to be on the safe side, don't press your face against the window and keep your head at least 1 foot (30 cm) away from the oven. Radiation decreases rapidly with distance.
Also, make sure that your microwave oven is in good condition. If it’s old or broken — or if the door doesn't close properly — consider getting a new one.
SUMMARY Microwaves are a form of electromagnetic radiation, similar to the radiation from cell phones. However, microwave ovens are designed to prevent radiation from escaping.
Every form of cooking reduces the nutrient value of food.
The main contributing factors are temperature, cooking time, and method. During boiling, water-soluble nutrients may leak out of the food.
As far as microwaves go, cooking times are generally short and the temperature low. Plus, the food is usually not boiled.
For this reason, you would expect microwave ovens to retain more nutrients than methods like frying and boiling.
One study on 20 different vegetables noted that microwaving and baking preserved antioxidants the best, while pressure cooking and boiling did the worst (3).
This study is often cited as evidence that microwaves degrade food. Yet, water was added to the microwaved broccoli, which is not recommended.
Keep in mind that the type of food or nutrient sometimes matters.
It is not recommended to heat human milk in a microwave because it can damage antibacterial agents in the milk (6).
With a few exceptions, microwaves tend to preserve nutrients very well.
SUMMARY All cooking methods reduce nutrient value, but microwaving generally preserves nutrients better than other methods.
Microwaving may reduce the formation of harmful compounds in certain foods.
One advantage of microwaving is that the food doesn't heat up nearly as much as it does with other cooking methods, such as frying.
Usually, the temperature doesn't surpass 212°F (100°C) — the boiling point of water.
However, fatty foods like bacon can become hotter.
Bacon is one food believed to form harmful compounds called nitrosamines when cooked. These compounds are created when nitrites in foods are heated excessively.
Another study showed that microwaving chicken formed far fewer harmful compounds than frying (8).
SUMMARY Microwaving may minimize the formation of harmful compounds that can form when cooking at high heat.
Many plastics contain hormone-disrupting compounds that can cause harm.
When heated, these containers may leach compounds into your food.
For this reason, do not microwave your food in a plastic container unless it is labeled microwave safe.
This precaution is not specific to microwaves. Heating your food inside a plastic container is a bad idea — no matter which cooking method you use.
SUMMARY Many plastics contain hormone-disrupting compounds like BPA, which can contaminate your food when heated. Never microwave a plastic container unless it's specifically labeled safe to use.
Microwaves do have some downsides.
For example, they may not be as effective as other cooking methods at killing bacteria and other pathogens that may lead to food poisoning.
That’s because the heat tends to be lower and the cooking time much shorter. Sometimes, food heats unevenly.
Using a microwave with a rotating turntable can spread the heat more evenly, and making sure that your food is heated sufficiently can help ensure that you kill all microorganisms.
It's also important to be careful when heating liquids. There’s a slight possibility that overheated liquids may explode out of their container and burn you.
Never heat baby formula or any food or beverage intended for small children in a microwave due to the risk of scald burns. To the reduce the risk of burns in general, mix what you microwaved and/or let it cool for a while (11).
SUMMARY If you microwave your food, make sure it is evenly heated to reduce your risk of food poisoning. Also, be careful when heating water above boiling point as it can erupt out of the container and burn you.
Microwaves are a safe, effective, and highly convenient cooking method.
There is no evidence that they cause harm — and some evidence that they are even better than other cooking methods at preserving nutrients and preventing the formation of harmful compounds.
Still, you shouldn’t over- or under-heat your food, stand too close to the microwave, or heat anything in a plastic container unless it’s labeled safe for use.