To nuke or not? 

Not so long ago, microwave ovens altered the way we were able to heat foods. They quickened the cooking process and promised more time for leisure activities. Though their technology was quite mysterious at first, most people adorned their homes with one of these innovative machines. 

However, within the past couple of decades, people began questioning whether microwaves were dangerous to health. Discover the hot and cold truth about microwaves in this article! 

How Do Microwaves Work?

Prior to microwaves, foods were generally cooked via conduction or convection. 

Specifically, conduction is the process by which heat or electricity is directly transmitted through a substance when there is a difference in temperature or electrical potential between adjoining regions sans movement of the material. 

Convection is the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise and colder, denser material to sink, which results in the transfer of heat.

On the other hand, microwave ovens cook food by literally injecting it with invisible microwaves. Microwaves are longer than infrared waves but shorter than radio waves.

A device inside the microwave oven - known as the magnetron - channels electrical energy from a power outlet to heated filaments. This creates a flow of electrons that transmit microwaves (the energy form) into the cooking chamber through an antenna. Then, the microwaves bounce around in the chamber and cook food via radiation heating. 

This form of heating excites molecules within an object by lodging in water, sugar, and fat. Because microwaves are fairly small, they really only heat the outside of thick foods. The inside of foods is subsequently heated through the conductive transfer of heat.

Are Microwaves Bad For You?

Despite being convenient, simple, and fast, many people possess strong opinions about microwaves. They tend to either associate microwaves with destroying nutrients and causing cancer or believing they are completely harmless. Here’s the hot truth.

Radiation

Indeed, microwaves produce electromagnetic radiation. This stirs nerves and skepticism because radiation is also associated with atomic bombs and cancer. 

However, microwaves produce non-ionizing radiation, which is similar to cell phone radiation just stronger. In addition, microwaves have metal shields and screens covering the window that prevents radiation from leaving the oven. To reduce radiation risk further, avoid touching or standing near microwaves while cooking.

All in all, there isn’t solid scientific evidence to show that microwave radiation is any more harmful than cellphone radiation. There is certainly room for interpretation here and critical thinking is never discouraged when reading anything related to health.

Nutrients

Cooking foods via any method can change the nutrient composition and more often than not, cooking reduces the nutritive value. Interestingly enough, microwaves appear to preserve nutrients better than other cooking methods. However, in some cases, it depends on the specific type of food or nutrient. As with everything in nutrition, one size doesn’t fit all.

The main contributing factors in reducing nutritive value through cooking include:

• Temperature
• Cooking time
• Method

Even amongst these categories, nuance exists. But in general: 

• The higher the temperature, the higher risk for carcinogens and free radical production

• The longer the cooking time, the more nutrients preserved (not microwaves though)

• Boiling foods in water leeches the most amount of nutrients. 

Now you know, no need to boil broccoli anymore! In fact, a somewhat recent study revealed that microwaving increased levels of sulforaphane, an anticarcinogenic compound found in broccoli.

Yet, another study showed that microwaving garlic for one minute reduced the cancer-fighting properties of garlic. 

This demonstrates nuance in food, cooking, and nutrients and helps explain how another study of 20 vegetables found that baking and microwaving preserved antioxidant content best. On the flip side, boiling and pressure cooking reduced antioxidant levels most.

It should also be noted that heating breast milk in the microwave is not recommended. Microwaving can cook unevenly and create “hot spots” that can burn a baby’s mouth.

Nonetheless, besides a few exceptions, microwaving seems to preserve nutrients pretty well.

Carcinogens

Microwaving food in plastic containers is unsafe and discouraged because it can cause harmful compounds to leech into the food. One example is the hormone-disrupting compound bisphenol-A (BPA), a compound linked to cancer, thyroid disorders, and obesity.

Only use microwave-safe dishes that include labeling to heat foods in a microwave.

Somewhat related, microwaving is less effective at killing bacteria and other pathogens that cause food poisoning. Although rotating turntables reduce this risk, microwaves without this feature can cook foods unevenly, increasing the risk of food poisoning.

Despite preserving nutrients better than other cooking methods, microwaving does seem to increase the risk of toxic compounds if not performed correctly. 

The Bottom Line

All in all, microwaving is a quick, effective, convenient cooking method. Despite popular belief, they don’t appear to pose radiation risk and they generally preserve most nutrients well. 

However, if used improperly, microwaving can increase the risk of some pathogens, harmful compounds, and burns. The correlation between microwaves and BPA consequences is the strongest evidence of harm caused by microwaves.

It’s important to always use microwave-safe dishes and avoid heating plastic of any kind.

If microwaves make your life less stressful, they are likely less detrimental to your health than worrying about the radiation levels of microwaves. When it comes to optimizing health, it’s often better to focus on big picture items like diet, exercise, sleep, and sunshine. 

References:

Gunnars K. Microwave Ovens and Health. Healthline. Updated February 18, 2022. https://www.healthline.com/nutrition/microwave-ovens-and-health#proper-heating.

Hogeback J. How Do Microwaves Work? Encyclopædia Britannica. https://www.britannica.com/story/how-do-microwaves-work.