Are Microwaves Dangerous?

Though microwaves have existed since the end of the Second World War, people are still debating whether or not they are dangerous. According to US government estimates, around 90% of all households in the US have at least one microwave

But what about their safety?

Let’s look at the real effects of microwave ovens and answer the question of whether or not microwaves are dangerous for use for our food.

The Science Behind Microwave Ovens

Microwaves are extremely powerful machines. They can emit around 2,000 watts of electricity instantly, and heat food to over 200°F.

This is only possible because of the high-frequency radio waves they use — the so-called microwaves, from which the machines get their name. The waves operate in the Microwave Region, or from 300 MHz to 300 GHz. 

The question of whether or not these waves are dangerous stems from the fact that microwaves are a form of non-ionizing electromagnetic radiation. This type of radiation is effective as it’s able to pass through paper, plastic, and glass. Food then absorbs it, which is why microwave ovens can heat food. 

So What Is Microwave Radiation?

There are two kinds of radiation:

  • Ionizing radiation (located in X-ray machines and nuclear power plants)
  • Non-ionizing radiation (found in microwaves, smartphones, etc.)

Ionizing radiation is hazardous when you receive large doses of it. This type of radiation can alter human DNA and lead to many forms of cancer if the radiation is severe enough and affects the body long enough. [1] 

Non-ionizing radiation emitted from microwaves does not deeply penetrate the tissues, so it doesn’t have the power to alter DNA and thus is not as harmful as ionizing radiation. 

But some studies have found that this type of radiation might have some adverse effects on human health, such as deficits in learning ability and memory functions observed after exposure to microwave radiation. [1-3]

This might be due to abnormalities induced by microwave radiation in the hippocampus structures.

However, this is dependent on the energy and exposure time.

Excessive exposure will cause local heating of tissues or photochemical reactions with possible permanent harm.

However, microwave ovens, concentrate the radiation inside — they don’t emit it on the outside. Companies that produce microwaves have to create proper barriers that prevent the radiation from leaking outside. [6-9] 

Although some studies from past years did find the highest radiation leakage from the front of the oven especially around the door. However, the fields clearly decrease rapidly with increasing distance from the microwave ovens.

But Is Microwave Radiation Dangerous for Our Food?

Besides the radiation itself and its effects on the human body, we need to discuss the effects microwaves have on food. 

Since vitamins are sensitive to water, light, oxygen, and temperature, some vitamin content is lost during all heating methods, but even more so with microwave heating methods. [10] especially vitamins A, C, and E with the highest rate of loss with vitamin E. Other studies also showed that the vitamin B12 content in foods also suffered considerable loss ranging between 30–40% loss. [10]

Also, other antioxidant capacities were all degraded more than conventional cooking techniques.

Lipids and lipid-containing foods are also sensitive to microwave heating, which oxidizes and degrades the fats more easily; however, this depends on both the heating time and the surrounding medium of the food inside the microwave oven. But the fat content was not affected during the thawing process in the microwave oven.

Carbohydrate and protein content of foods are also very sensitive to microwave heating.

But, on the other hand, concerning flavor and color of the food, when compared to other food heating methods, including covered pot, and pressure cooking, microwave heating was a fast and straightforward way to raise the chlorophyll retention after heating thereby sparing the foods’ natural color and flavor better.

Key Takeaways 

Microwaves generally do decrease the number of positive compounds in food.

But the radiation they use is not dangerous as it doesn’t emit outside of the oven in modern microwave ovens.

The choice for using a microwave is your own. However, cooking food on a regular fire does keep the nutritional content more readily available for our bodies to use. Regular heating over a fire is also generally better as it alters the food components much less than with the use of microwaves.

References:

  • [1] Ghandhi, S.A., Smilenov, L.B., Elliston, C.D. et al. Radiation dose-rate effects on gene expression for human biodosimetry. BMC Med Genomics 8, 22 (2015) doi:10.1186/s12920-015-0097-x 
  • [2] Li HJ, Peng RY, Wang CZ, Qiao SM, Yong Z, Gao YB, et al. Alterations of cognitive function and 5-HT system in rats after long term microwave exposure. Physiol Behav. 2015;140:236–246. doi: 10.1016/j.physbeh.2014.12.039. [PubMed] [CrossRef] [Google Scholar]
  • [3] Vakalopoulos C. The EEG as an index of neuromodulator balance in memory and mental illness. Front Neurosci. 2014;8:63. doi: 10.3389/fnins.2014.00063. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
  • [4]  Thuröczy G, Kubinyi G, Bodo M, Bakos J, Szabo L. Simultaneous response of brain electrical activity (EEG) and cerebral circulation (REG) to microwave exposure in rats. Rev Environ Health. 1994;10:135–148. doi: 10.1515/REVEH.1994.10.2.135. [PubMed] [CrossRef] [Google Scholar]
  • [5]  Chizhenkova R. Slow potentials and spike unit activity of the cerebral cortex of rabbits exposed to microwaves. Bioelectromagnetics. 1988;9:337–345. doi: 10.1002/bem.2250090403. [PubMed] [CrossRef] [Google Scholar]
  • [6] Dominique Belpomme, Lennart Hardell, Igor Belyaev, Ernesto Burgio, David O.Carpenter. Thermal and non-thermal health effects of low intensity non-ionizing radiation: An international perspective. Environmental Pollution Volume 242, Part A, November 2018, Pages 643-658. https://doi.org/10.1016/j.envpol.2018.07.019
  • [7] Cross GA, Fung DY. The effect of microwaves on nutrient value of foods. Crit Rev Food Sci Nutr. 1982;16(4):355-81. DOI: 10.1080/10408398209527340
  • [8] Jiménez-Monreal AM1, García-Diz L, Martínez-Tomé M, Mariscal M, Murcia MA. Influence of cooking methods on antioxidant activity of vegetables. J Food Sci. 2009 Apr;74(3):H97-H103. doi: 10.1111/j.1750-3841.2009.01091.x.
  • [9] Vallejo, F. , Tomás?Barberán, F. and García?Viguera, C. (2003), Phenolic compound contents in edible parts of broccoli inflorescences after domestic cooking. J. Sci. Food Agric., 83: 1511-1516. doi:10.1002/jsfa.1585
  • [10] Hao Jiang, Zhigang Liu & Shaojin Wang (2017): Microwave processing: Effects and impacts on food components, Critical Reviews in Food Science and Nutrition, DOI: 10.1080/10408398.2017.1319322