If you’ve spent any amount of time watching viral videos on YouTube, you probably understand why many people are wary about using microwaves. Videos showing anything from marshmallows to iPhones, to propane tanks being microwaved have certainly created a sense of caution and sometimes, downright unease when reheating your leftovers.
If you’re the kind of person who insists on standing ten feet away from your microwave when it’s on, it’s likely you’ve also heard the rumors that microwaves can zap essential nutrients or even poison your food.
How Microwaves Work
For the last half-century, microwaves have been used by households and businesses for their convenience and cooking speed. A microwave is a form of electromagnetic radiation, containing enough energy to only affect water molecules due to their structure.
Microwave ovens cook food at very high temperatures for a short period of time using microwave radiation. Dielectric heating is the process in which this radiation prompts polar molecules to produce thermal energy.
The oven passes non-ionizing radiation through food, resulting in the absorption of heat through water, ultimately heating the food quickly, much faster than a conventional oven.
Let’s look at some common rumors about microwave ovens and break them down:
6 of The Most Common Microwave Myths Debunked
1. “Microwaves Poison Food”
A 1995 in-vivo study was conducted on 10 male and 10 female rats for 13 weeks, some on a human diet and some on a cereal-based rodent diet, some with microwaved foods and some with foods cooked in a conventional oven. The results of that study indicated no adverse effects on food toxicity1
The FDA spokesman Michael Herndon says no studies show long or short-term health effects from heating food in microwave-safe plastic. Herndon said this in response to Olga Naidenko, Ph.D., who cited another study finding chemicals that leached into food when heated in a microwave.
One study has found that some “microwave safe” products released toxic doses of chemical Bisphenol A (BPA). BPA is a key ingredient in household plastics like Tupperware containers. Rubbermaid containers and Enfamil liquid infant formula contained the highest amounts of leaked BPA.
The chemical has shown to cause neurological and developmental damage in tested animals, such as genital defects, behavioral changes, and unusual mammary glands, and also correlates with a higher risk of breast cancer in women. BPA is known to cause irreversible damage, and tiny amounts can trigger cell change, similar to how a hormone such as estrogen operates. BPA can be especially harmful to infants and small children.
However, it’s important to note that the levels released in the study were extremely low; in fact, similar levels are likely to be found in unfiltered tap water. Also, remember that increased food toxicity results from the chosen heating container, not the process of microwaving as a method of cooking3.
Keep reading to find out how you can avoid BPA leakage into your food when microwaving.
2. “Microwaves Poison Us”
Ionizing radiation can cause chemical damage, but microwaves only generate thermal energy, which is non-ionizing and creates heat in moist food and tissue in the oven, so they don’t cause food to become toxic or cause cancer. The microwave radiation escaping when the door is closed is tiny, making the level of the radiation outside the oven safe.
Damaged or worn oven doors can cause radiation leakage, which does create unsafe radiation levels. Ensure your microwave is less than 10 years old, and if it isn’t, replace it. If the gaskets on the door are worn, it’s also time to replace it. Gaskets are the shaped rubber that that seal the junction between the oven and the door.
Radiation leakage is certainly a danger when cooking food, but if you are using a high-functioning electric oven, there is no need to vacate your kitchen when microwaving your meals2.
3. “Microwaves Kill Antioxidants”
Any scientific evidence of antioxidant degradation as a result of microwaving remains to be seen. A 2010 study was conducted to test the effect of microwaving vegetables with antioxidant capacity and concluded that microwaving food has no effect on the antioxidant capacity of vegetables4.
Find out the benefits of antioxidants for illnesses and inflammation. The video below from Nutrition Facts explores this subject further.
4. “Microwaves Degrade Nutrients”
FALSE (with an exception)
According to a 1982 study, the nutritional effects of microwaves on protein, fats and minerals are marginal, and while there are no effects on carbohydrates, and the effects on vitamin retention are very similar to those of conventional cooking. Nutrient degradation, in all cooking, is dependent on water content, cooking time and temperature5.
One 1998 study found that vitamin B12, which is a vital nutrient for women, especially those who do not consume high amounts of meat and dairy, is converted to an inactive form when microwaved. However, a 1998 seven-day in vivo research study found that the resulting compound does not degrade vitamin B12 in the human body6.
5. “Microwaves Denature Proteins”
There is a big BUT: when a protein is heated, regardless of the mechanism used, whether it be in a microwave or a conventional oven, denaturation will occur. Denaturation is a process in which proteins become inactive when exposed to specific changes like salinity, temperature, and acidity.
6. “Microwaves Can Prevent Foodborne Illnesses”
Believe it or not, aside from the benefit of convenience, some studies have concluded that microwaving food and beverages could also pose health benefits. Results from a 1991 study demonstrated that microwaving food inactivates foodborne hepatitis A7.
The same 2010 study on antioxidant capacity showed that boiling vegetables can degrade their phenolic content, while microwaving does not. Phenols, which have antioxidant effects, are believed to prevent cancer and promote healthy aging.
There are always risks associated with microwave radiation. However, the stigma of microwaves being the “killers in our kitchens” is fairly unfounded. In addition to constantly maintaining, quality checking, cleaning and replacing your microwave, here are some other tips for safely using your microwave:
- Remember that “Microwave safe” plastic does not always truly mean safe
- Try to use glass and ceramic containers
- Avoid microwaving canned foods and metals, as the lining of the can contain BPA, which is toxic even in low doses
- Never, EVER turn on an empty microwave as it can potentially cause the microwave to explode
- Avoid microwaving anything in plastic, such as containers, cling-film or water bottles.
- If you are concerned about nutrient loss when cooking vegetables, steaming them will cause the best vitamin-retention
- Jonker, D., & Til, H. (1995). Human diets cooked by microwave or conventionally: Comparative sub-chronic (13-wk) toxicity study in rats. Food and Chemical Toxicology, 33(4), 245-256. doi:10.1016/0278-6915(94)00140-j
- Zamanian, A., & Hardiman, C. (2005). Electromagnetic radiation and human health: A review of sources and effects. High Frequency Electronics, 4(3), 16-26.
- Lab results: Rust, S. (2008, August 14). Bisphenol A Analysis Report. XenoAnalytical LLC.
- Natella, F., Belelli, F., Ramberti, A., & Scaccini, C. (2010). Microwave And Traditional Cooking Methods: Effect Of Cooking On Antioxidant Capacity And Phenolic Compounds Content Of Seven Vegetables. Journal of Food Biochemistry. doi:10.1111/j.1745-4514.2009.00316.x
- Cross, G. A., Fung, D. Y., & Decareau, R. V. (1982). The effect of microwaves on nutrient value of foods. C R C Critical Reviews in Food Science and Nutrition, 16(4), 355-381. doi:10.1080/10408398209527340
- Watanabe, F., Abe, K., Fujita, T., Goto, M., Hiemori, M., & Nakano, Y. (1998). Effects of Microwave Heating on the Loss of Vitamin B 12 in Foods. J. Agric. Food Chem. Journal of Agricultural and Food Chemistry, 46(1), 206-210. doi:10.1021/jf970670x
- Allen, S., & Palmer, D. (1991). Foodborne Hepatitis A: Evidence that Microwaving Reduces Risk? Journal of Infectious Diseases, 163(4), 918-918. doi:10.1093/infdis/163.4.918