Die Mikrowelle - Ist sie wirklich so böse?

The microwave - Is it really that evil?

Richard Staudner
Richard Staudner

The Optimizer

The topic of microwaves has long been ticked off for most of us. It is evil through and through! The microwave destroys nutrients, makes blind and impotent (at least cats). Is this really true or should we refresh our knowledge a bit here? 

A little physics - What are microwaves? 

The word microwave describes a range of radiation with a certain frequency or wavelength. Microwaves are all beams between 0.3 (=300MHz) and 300 GHz. (Giga- or Mega-)Hertz is the international unit of frequency and stands for vibrations per second. This type of radiation is also used in the kitchen appliance we know, the microwave oven (1). The whole thing works like this: The appliance generates an electromagnetic field, this transports a force away from the source into the interior of the microwave oven. There it hits a food and interacts with atoms and molecules. Polar molecules (i.e. those with + and - poles), such as water, spin and charged particles begin to flow in the current of the field. Collisions with other molecules create heat and this thermal effect warms up our food (2).

Shortcut: What really happens when you use the microwaves!

The cooking method has several advantages: it is fast, energy-saving compared to other cooking methods, a microwave oven takes up little space and the food hardly burns. The purchase is cheap and, theoretically, with a fan and turntable, wonderfully even heating of food is possible (3-5).

Great, isn't it? But now a few questions arise: What do these rays do to our food? And more importantly, what are they doing to us? Are they dangerous?

Microwave radiation is currently being researched again worldwide, but the results are not conclusive. Adverse effects on fertility, carcinogenesis and mental health are suspected. The data mostly come from animal studies, or inconclusive epidemiological studies. In addition, most values come from studies with microwave radiation, which also emanates from cell phones. Nevertheless, limits have been set for safety. These are exceeded if you stand directly in front of a microwave while it is running. As soon as you move a few meters away from it or stand in another room, this does not matter. Vitamins or other nutrients are not necessarily destroyed more in the microwave than in other cooking methods. On the contrary: In the case of vitamin C, for example, but also other nutrients, more is preserved in the microwave. As with other cooking methods, the cooking time should be kept as short as possible and the intensity should be low. If you want to know more about what is behind it and what biological mechanisms are suspected, you can read more here: 

Microwave radiation and our health!

In order to clarify the question of the effect on health, we must first return a bit to the physics touched on earlier. As already mentioned, "microwaves" are a series of waves or even radiations with a certain frequency. A microwave oven usually operates at 2450 MHz because this is the range that best activates polar water molecules (5). But other devices also use this frequency range: cell phones use frequencies between about 450-1980 MHz, the WLAN router emits waves at 2400 MHz (1). 

So when we look at the harmful effects of microwaves, we should not lose sight of the big picture. The radiation of microwaves is just as harmful (much or little) as that of cell phones, WLANs, Bluetooth headphones, etc. We still have to differentiate in the intensity of the radiation, because as we know: The dose makes the poison. 

While we now know that high-power microwave radiation definitely has adverse effects, this is still unclear for normal-intensity radiation. Many epidemiological studies come up with contradictory results (1). In order to clarify this issue, the ICNRP, an international commission for the protection against non-"ionizing radiation", was founded. Non-ionizing radiation refers to an even wider range of "weaker" radiation, which includes microwave radiation (2). The counterpart would be ionizing radiation, which includes, for example, radioactive radiation, which we know is harmful. 

The ICNRP adjusted its recommended reference values in 2020. These are expressed in SAR (specific absorption rate), which corresponds to the radiation exposure per kg body weight. The reference values are based on current study results. There is always criticism here, as the values are taken from animal experiments, but it is very difficult and above all unethical to carry out experiments on humans. Epidemiological studies are also challenging in this area, since the described consequences can only be recognized after a long time and often many external factors play a role, which could also, or partly, be responsible for negative effects. 

The harmful mechanisms of action

In order to scientifically substantiate the effect of a substance, or in this case an environmental factor, it is essential to clarify the biological mechanisms behind it. Science has not yet fully succeeded in this, but there are already some approaches: 

As already mentioned, the electromagnetic fields can produce heat, exactly this effect can also happen in the body, this is the thermal effect. As a second mechanism, very low frequencies can stimulate nerves or even cause the destruction of cell membranes. However, these low frequencies are below those of microwaves (2). In addition, other "non-thermal" effects are suspected.

Fertility

Kesari et al. (6) look at male fertility under the influence of microwaves (such as from cell phones, laptops, but also microwave ovens) and conclude that these probably have a negative effect on sperm quality and quantity. One cause seems to be a higher number of reactive oxygen species (ROS), but the true biological mechanisms behind this are unclear (6). Other research groups also conclude that microwave radiation via ROS and associated oxidative stress decreases sperm quality, shrinks testes, and decreases testosterone levels. Disturbed menstrual cycles in female animals are also suspected (7). Practically, however, these are all animal studies. 

Santini et al put forward a theory of the mechanism for this and bring the mitochondria into play: Apparently, the radiofrequency waves can disrupt the electron transport chain of the mitochondria and thus the energy supply there. As a result, the balance of ROS generation and ROS degradation gets out of control. This can be detrimental to spermatogenesis, i.e. production, and lead to lower vitality, motility, and damage to the shape (8).

Cancer

The IARC (=International Agency for Research on Cancer) classified radio waves and microwaves, respectively, as possibly carcinogenic in 2011, although microwave ovens are not explicitly mentioned here, but primarily telephones, TV and radio signals are treated (9).

In general, there is increased research on cell phones regarding the harmful effects of microwaves: In case-control studies, a consistent association of increased risk for glioma and acoustic neuroma (both brain tumors) and cell phone use is evident. Also, according to Belpomme et al., despite mixed data, a trend toward harmful effects is evident (10). An analysis of a number of studies looking at radio waves but also a few on microwaves shows that there is no clear relationship. Although the authors point to a weak epidemiological association, they do not reach a conclusion because the data are too mixed (11).

Mental Health

New conjectures associate microwave radiation also with mental diseases. Here one speaks of a" Microwave syndrome". This syndrome is diagnosed in people who are increasingly exposed to microwave radiation in their work. The syndrome manifests itself with exhaustion, headaches, sleep disorders, irritability, lack of concentration, depression, memory changes, restlessness, and other symptoms. From initial experiments, it has been suggested that certain voltage sensors in the nervous system are very sensitive to microwave radiation. These release neurotransmitters and hormones in the brain. This, too, was first confirmed in animal and cell experiments (12).

And is there an antidote?

Since it is suspected that the negative effects occur via reactive oxygen species and thus via oxidative stress, theories about possible antidotes have also been put forward here. Antioxidants seem to provide remedies. Melatonin, green tea extract, vitamin C and E but also Moringa oleifera extract have been studied and appear to attenuate damage in animal studies. This has not yet been studied in humans (6,8). The Chaga mushroom seems to be an interesting choice as probably the strongest antioxidant known to us. 

Is the microwave now more harmful than my phone?

The Specific Absorption Rate (SAR) is very high when talking on the phone (cell phone to the ear), carrying the cell phone in the pocket, having the WLAN-connected laptop directly on the lap, or using a microwave oven (10). However, according to observational studies, the short-term radiation of the microwave oven is many times higher than that of the cell phone (13). However, it is difficult to put these in relation to each other, as this seems to depend on the type of phone use. Unfortunately, we now use the telephone very intensively on a daily basis. 

What we can do, however, is take a closer look at how the microwave is used. The microwave only radiates when the door is closed. Inside, the rays are mostly reflected by the walls, and rays can escape through the glass door. Measurements show that the radiation exposure to the left and right of the appliance is much lower than directly in front of it (14). It also shows that the radiation exposure is stronger when the power is higher (i.e. uses more watts) and when the device is older (15,16). 

Furthermore, the radiation decreases sharply with increasing distance from the microwave. When standing only 1 m away from the device, the radiation exposure on individual body parts reaches SAR values above 8 W/kg, which is above the recommended limit of the ICNRP for the general population and only just below the limit for workplace exposure. At 2 m, the value is mostly below 3 W/kg, but even this is still just above the reference values for the general population (2.17).

According to Belpomme et al., no effects were detectable with short-term exposure, while other research teams attribute the same risk to intensive short-term exposure as to low-intensity long-term exposure (10).

Unfortunately, the answer to all the questions is disappointing: we don't know. Research has made assumptions, some of which have been confirmed, and some of which have not been confirmed. What is certain, however, is that the harmful effect of the microwave cannot be considered alone. The following applies here: Better Safe than Sorry... and if you want to be on the safe side, you should limit not only the use of the microwave, but also the use of your phone and laptop, and perhaps consider carrying your cell phone in your backpack instead of in your pants pocket. In any case, avoid waiting for your food in front of the microwave; it's best to go to another room instead. 

There was something else! Does the microwave make worthless mush out of my food?

As mentioned above, the use of a microwave oven brings us some benefits. Some studies have put these benefits in relation to the loss of nutrients and came up with the following results: 

At Carbohydrates, such as in potatoes, the structure of the starch is changed, which alters digestibility (3). Experiments with pulses also showed that the starch from pulses cooked in a pressure cooker is more digestible than that from the microwave (18). Sugars are broken down much more quickly and possibly maillard products could also be formed to a greater extent, which on the one hand is positive for the taste, but on the other hand could also be harmful to health (3).

Proteins are increasingly degraded in the microwave, which also changes the taste. Here, heating for only a short time is advised. The digestibility of proteins in legumes was only slightly different in pressure cooker and microwave (3,18).

Fat are far more under the influence of microwave cooking than proteins or carbohydrates. Microwave cooking results in increased production of unsaturated fatty acids, peroxides, acids, and oxidized fats. Also, phytosterols (with presumed protective effects against cardiovascular diseases) are degraded (3,19). On the other hand, in experiments with baby food (milk), no significant difference in quality was detected between milk heated in the microwave and in a water bath. Here, only very short cooking times of a few seconds were used to reach the desired temperature (5).

Minerals seem to be only slightly affected by microwave cooking. Most mineral losses occur due to "leaching" in the cooking water. Therefore, microwave cooking retains a relatively high proportion of minerals compared with alternative heating methods (18,20).

With the Vitamins it is not possible to draw an exact line. For vitamins A, C, and E, microwave preparation is probably gentler than infrared (e.g., ceramic hob) (3). Vitamin C is water soluble and therefore tends to be destroyed more when cooked in a water bath than in a microwave (20,21). Other experiments with vitamin C show no difference depending on the heating method (4). Vitamin K shows different losses depending on the type of vegetable; for some, losses are higher in the microwave than in conventional cooking, and for some, they are lower. For some foods, the content even increases due to the preparation method (21). In experiments with vegetables, the vitamin E content was found to be increased in leafy vegetables and decreased in starchy ones; again, different preparation methods were beneficial depending on the vegetable. Similar results were obtained with β-carotene (21). In general, however, vitamin losses seem to depend on duration and power (3). So rather less wattage and shorter heating duration. 

Antioxidants and other phytochemicals in our food are also important. The losses of these are mainly caused by dissolution in water. However, duration and performance also play an important role here (20). In experiments with spices, microwave drying showed lower losses of flavors than conventional drying. Nevertheless, almost all aroma compounds are lost when heated in the microwave for too long (3).

Conclusion: 

It is not one hundred percent proven or disproven whether the microwave causes damage to health. But there is very strong circumstantial evidence that it does. 

Therefore, my recommendation is, if you use a microwave, stand a few meters away or in another room after switching it on. This way you are on the safe side as far as radiation is concerned. 

If this topic is important to you or even worries you, then you should definitely also pay attention to how you use your cell phone. 

Short checklist what would be possible:

  • Cell phone in the backpack or on flight mode
  • Put cell phone in another room at home (good for productivity) 
  • Use speakers (when you are alone)
  • Use headset without real cable but with air hose (podcast follows)
  • Do not work with the laptop on your lap
  • Turn on WLAN router only when in use 

Food conclusion

As for your food, no the microwave doesn't make worthless mush out of our food. In some respects, it even performs better than conventional heating in a saucepan. If you're worried about toxic ingredients or vitamin loss, you can probably rest easy, because the differences don't seem to be significant. Nevertheless, it makes sense to switch to the gentlest cooking methods: Steaming over steam, because cooking in a pan or in a tube, or even grilling, also offer many opportunities for vitamin losses and the creation of unhealthy substances. Nutrient losses can also be reduced well with all preparation variants by short cooking times and low heat. Don't cook and fry your food to death, and remember that some food tastes good raw. 

I hope I could help you and clear up some old dogmas. I myself have always been an opponent of the microwave, but we must remain objective. 

If you prefer to listen to the post, you can also find it on my podcast at. https://richardstaudner.at/podcasts/ or on all podcast platforms. 

One thing right away, antioxidants are considered antidotes to oxidative stress, such as radiation. And the Chaga mushroom is considered the most powerful antioxidant, as confirmed by the Vienna University of Technology. Give it a try!

Here you can get Chaga in different forms: https://theartofraw.at

With the code "richard20" there is also 20 % on all products! 

Meal and see you soon!

Your Performance Optimizer 
Richard Staudner

Literature: 

1, Zhi WJ, Wang LF, Hu XJ. Recent advances in the effects of microwave radiation on brains [Internet]. Vol. 4, Military Medical Research. BioMed Central Ltd; 2017 [cited 2021 Feb 13]. Available from: https://pubmed-ncbi-nlm-nih-gov.uaccess.univie.ac.at/29502514/

2 Ziegelberger G, Croft R, Feychting M, Green AC, Hirata A, d'Inzeo G, et al. Guidelines for limiting exposure to electromagnetic fields (100 kHz to 300 GHz). Vol. 118, Health Physics. Lippincott Williams and Wilkins; 2020. p. 483-524. 

3. Jiang H, Liu Z, Wang S. Microwave processing: effects and impacts on food components. Crit Rev Food Sci Nutr [Internet]. 2018 Sep 22 [cited 2021 Feb 15];58(14):2476-89. Available from: https://www.tandfonline.com/doi/full/10.1080/10408398.2017.1319322

4 Géczi G, Horváth M, Kaszab T, Alemany GG. No Major Differences Found between the Effects of Microwave-Based and Conventional Heat Treatment Methods on Two Different Liquid Foods. PLoS One [Internet]. 2013 Jan 16 [cited 2021 Feb 15];8(1). Available from: /pmc/articles/PMC3547058/.

5 Nowak JK, Kurek S, Walkowiak J, Drzymała-Czyż S. Infant formula fatty acid profile following microwave heating. PLoS One [Internet]. 2020 Aug 1 [cited 2021 Feb 16];15(8 August). Available from: https://pubmed-ncbi-nlm-nih-gov.uaccess.univie.ac.at/32857786/

Kesari KK, Agarwal A, Henkel R. Radiations and male fertility [Internet]. Vol. 16, Reproductive Biology and Endocrinology. BioMed Central Ltd; 2018 [cited 2021 Feb 13]. Available from: https://pubmed-ncbi-nlm-nih-gov.uaccess.univie.ac.at/30445985/

7. Di Ciaula A. Towards 5G communication systems: Are there health implications? Environ Heal J homepage [Internet]. 2018 [cited 2021 Feb 13]; Available from: www.elsevier.com/locate/ijheh

8. Santini SJ, Cordone V, Falone S, Mijit M, Tatone C, Amicarelli F, et al. Role of mitochondria in the oxidative stress induced by electromagnetic fields: focus on reproductive systems [Internet]. Vol. 2018, Oxidative Medicine and Cellular Longevity. Hindawi Limited; 2018 [cited 2021 Feb 22]. Available from: https://pubmed-ncbi-nlm-nih-gov.uaccess.univie.ac.at/30533171/

9. International Agency for Research on Cancer. IARC CLASSIFIES RADIOFREQUENCY ELECTROMAGNETIC FIELDS AS POSSIBLY CARCINOGENIC TO HUMANS [Internet]. Lyon; 2011 May [cited 2021 Feb 16]. Available from: http://www.iarc.fr/

10 Belpomme D, Hardell L, Belyaev I, Burgio E, Carpenter DO. Thermal and non-thermal health effects of low intensity non-ionizing radiation: An international perspective [Internet]. Vol. 242, Environmental Pollution. Elsevier Ltd; 2018 [cited 2021 Feb 13]. p. 643-58. Available from: https://pubmed-ncbi-nlm-nih-gov.uaccess.univie.ac.at/30025338/

11 Gupta S, Sharma RS, Singh R. Non-ionizing radiation as possible carcinogen [Internet]. International Journal of Environmental Health Research. Taylor and Francis Ltd; 2020 [cited 2021 Feb 22]. Available from: https://www.tandfonline.com/action/journalInformation?journalCode=cije20

12. Pall ML. Microwave frequency electromagnetic fields (EMFs) produce widespread neuropsychiatric effects including depression [Internet]. Vol. 75, Journal of Chemical Neuroanatomy. Elsevier B.V.; 2016 [cited 2021 Feb 16]. p. 43-51. Available from: https://pubmed-ncbi-nlm-nih-gov.uaccess.univie.ac.at/26300312/

13. Roser K, Schoeni A, Struchen B, Zahner M, Eeftens M, Fröhlich J, et al. Personal radiofrequency electromagnetic field exposure measurements in Swiss adolescents. Environ Int. 2017 Feb 1;99:303-14. 

14. Plets D, Verloock L, Van Den Bossche M, Tanghe E, Joseph W, Martens L. EXPOSURE ASSESSMENT OF MICROWAVE OVENS AND IMPACT ON TOTAL EXPOSURE IN WLANs. Radiat Prot Dosimetry [Internet]. 2015 May 8 [cited 2021 Feb 15];168(2):ncv284. Available from: https://academic.oup.com/rpd/article-lookup/doi/10.1093/rpd/ncv284

15. Lahham A, Sharabati A. Radiofrequency radiation leakage from microwave ovens. Radiat Prot Dosimetry [Internet]. 2013 Dec 1 [cited 2021 Feb 22];157(4):488-90. Available from: https://academic.oup.com/rpd/article-lookup/doi/10.1093/rpd/nct173

16. Alhekail ZOI. Electromagnetic radiation from microwave ovens. J Radiol Prot [Internet]. 2001 Aug 24 [cited 2021 Feb 22];21(3):251-8. Available from: https://iopscience.iop.org/article/10.1088/0952-4746/21/3/303

17. Lopez-Iturri P, De Miguel-Bilbao S, Aguirre E, Azpilicueta L, Falcone F, Ramos V. Estimation of radiofrequency power leakage from microwave ovens for dosimetric assessment at nonionizing radiation exposure levels. Biomed Res Int. 2015;2015. 

18. Khatoon N, Prakash J. Nutritional quality of microwave-cooked and pressure-cooked legumes. Int J Food Sci Nutr [Internet]. 2004 Sep [cited 2021 Feb 15];55(6):441-8. Available from: https://www.tandfonline.com/action/journalInformation?journalCode=iijf20

19, Hu H, Liu H, Shi A, Liu L, Fauconnier M, Wang Q. The Effect of Microwave Pretreatment on Micronutrient Contents, Oxidative Stability and Flavor Quality of Peanut Oil. Molecules [Internet]. 2018 Dec 25 [cited 2021 Feb 15];24(1):62. Available from: http://www.mdpi.com/1420-3049/24/1/62

20 López-Berenguer C, Carvajal M, Moreno DA, García-Viguera C. Effects of microwave cooking conditions on bioactive compounds present in broccoli inflorescences. J Agric Food Chem [Internet]. 2007 Nov 28 [cited 2021 Feb 15];55(24):10001-7. Available from: https://pubs.acs.org/sharingguidelines

21. Lee S, Choi Y, Jeong HS, Lee J, Sung J. Effect of different cooking methods on the content of vitamins and true retention in selected vegetables. Food Sci Biotechnol [Internet]. 2018 Apr 1 [cited 2021 Feb 15];27(2):333-42. Available from: /pmc/articles/PMC6049644/.

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