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.
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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 like how your hands heat up when you rub them together.
Microwaves primarily affect water molecules but can also heat up fats and sugars — just to a lesser extent than water.
SUMMARYMicrowave 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 like 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.
SUMMARYMicrowaves are a form of electromagnetic radiation, like 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 is 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.
According to two reviews, microwaving does not reduce nutrient value more than other cooking methods (1).
An older study on 20 different vegetables noted that microwaving and baking preserved antioxidants the best, while pressure cooking and boiling did the worst (2).
However, one older study found that just 1 minute of microwaving destroyed some of the cancer-fighting compounds in garlic, while this took 45 minutes in a conventional oven (3).
However, a recent study showed that mild microwaving actually increased the levels of the anticarcinogenic compound sulforaphane in broccoli (4).
Keep in mind that the type of food or nutrient sometimes matters.
Microwaving breast milk has been found to be effective in preventing cytomegalovirus infections (5).
With a few exceptions, microwaves tend to preserve nutrients very well.
SUMMARYAll 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.
According to one 1989 study, heating bacon in the microwave caused the least nitrosamine formation of all cooking methods tested (6).
SUMMARYMicrowaving 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.
A notable example is bisphenol-A (BPA), which has been linked to conditions like cancer, thyroid disorders, and obesity (7, 8).
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.
SUMMARYMany 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 reduce the risk of burns in general, mix what you microwaved or let it cool for a while (9).
SUMMARYIf you microwave your food, make sure it’s 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 should not:
- overheat or underheat your food
- stand too close to the microwave
- heat anything in a plastic container unless it’s labeled safe for use
Health Canada established the Radiation Emitting Devices Regulations, under the Radiation Emitting Devices Act in order to "govern the design, construction and function of microwave ovens that are sold, leased or imported into Canada."
Part III (Microwave Ovens) of the Radiation Emitting Devices Regulations (C.R.C., C. 1370) specifies the following limits for the leakage radiation at 5 cm from the surface of the microwave oven:
- 1.0 mW/cm2 with test load
- 5.0 mW/cm2 without test load
Information about measuring equipment for microwave oven leakage can be obtained from the suppliers and manufacturers of such instruments. The Radiation Emitting Devices Regulation requires that the measuring instrument must be capable of measuring a power density of 1.0 mW/cm2 with an accuracy of ±2dB or better and have an indicator with response time not greater than 3 seconds.
Persons exposed to microwave or radiofrequency radiation may also wish to consult Health Canada's Safety Code 6: Health Canada's Radiofrequency Exposure Guidelines
Health Canada states: "The exposure limits in Safety Code 6 are based on an ongoing review of published scientific studies, including both internal and external authoritative reviews of the scientific literature, as well as Health Canada's own research. The code is periodically revised to reflect new knowledge in the scientific literature."
Microwaves are radio waves with frequencies ranging from around 300 million cycles per second (300 MHz) to 3 GHz. RF. A standard measure of exposure for microwave energy is the Specific Absorption Rate (SAR) or rate of tissue energy absorption measured in watts per kilogram of tissue.
- Microwave radiation leakage can damage human cells and tissues.
- All appliances working on electricity produce a toxic electromagnetic field (EMF) of approximately 60 hertz. This is over and above potential microwave leakage from appliances or devices.
Microwave leakage is serious enough that the FDA sets strict limits on it for the manufacturers. But once door seals age, leaking tends to exceed those limits, often at head level. That’s bad news, because the microwave energy inside a microwave oven is massive!
- Frequency inside your microwave 2.45 BILLION hertz.
- Frequency shown to start harming the human body: over 10 hertz
That’s 2.45 billion vs. 10 hertz. It doesn’t take very big leak for the damage to begin. (One top culprit: aging door seals)
The facts about microwaves & cataracts- Eyes are especially vulnerable to microwaves. That’s because unlike other areas of the body, they lack the blood vessels to dissipate the heat and cellular stress.
- The first suspected clinical case of microwave-caused cataracts was reported by Hirsch and Parker as early as 1950's. (Sulman 1980).
- For decades, cataracts have been reported in workers exposed to this type of radiation. (On the back of the lens where radiation cataracts usually occur.)
In a microwave oven, alternating current forces atoms reverse polarity at a startlingly high rate. This creates such violent friction that the water inside the food molecules begin to vibrate and heat up.
The dangers of microwaved foods.Microwaves break chemical and molecular bonds, and can literally rip atoms apart, disrupting the basic biochemical structures of life. It’s no wonder foods cooked in such a way become so harmful to consume.Government and industry studies suggest they pose no threat, but a growing body of knowledge now contradicts those claims.
Microwaved foods lose nutrition.The Swiss scientist Hans Hertel, was the first to study microwave dangers, specifically, how cooking degrades and depletes food of nutrients—an effect that shows up in study participants' blood samples.
Microwaving makes food unhealthyWhen the microwave radiation destroys and deforms food molecules, new harmful compounds form (radiolytic compounds). These dangerous compounds harm the body in many ways.
Microwaved meals change blood chemistryThe research, from Search for Health (Spring, 1992): After study participants consumed microwaved vegetables, Swiss Scientist Hertel measured the following effects:
- Cholesterol levels increased rapidly.
- Hemoglobin decreased significantly (creating anemic tendencies.)
- Lymphocytes (white blood cells) showed a significant term decrease.
- Increased stress (evidence by the increase of leukocyte)
- NOTE: Leukocyte response can indicate pathogenic effects such as poisoning and cell damage.
The research, from Pediatrics (vol. 89, no. 4, April 1992) on microwaving human breast milk:
- Cuts down on lysozyme activity
- Promotes potentially dangerous bacteria.
- Milk heated to 72 degrees lost a full 96% of all immunoglobulin-A antibodies, which fight invading microbes.
Researcher’s conclusion: microwaving likely reduces and reverses the potential benefits of food, above and beyond the harm heating itself causes.
Another study of microwave problems reported in the medical journal, The Lancet, showed that when infant formula was microwaved for ten minutes, it altered the structure of its component amino acids, possibly resulting in functional, structural and immunological abnormalities.