Is microwave cooking bad for health?

Manoj Pandey*

Radiation, or the range of electronic-magnetic rays, is used by humans in numerous waves but is often under suspicion that it is harmful to humans.  

Some forms of radiation is indeed harmful, even hazardous, but not all. In this very column, we have earlier talked about the impact of cellphone radiation in general, and 5G radiation in particular, on the health of humans and other living beings. We have discussed the science of electro-magnetic radiation in detail in these articles. Let us, therefore, go straight to the subject – does the microwave radiation that is generated in microwave ovens harm us in some way.

We find many shades of opinions and claims about microwave radiation on the web and social media, and we will dissect the major ones here.

Microwaves are intrinsically harmful, and our tissues burn when these rays fall on us.

This statement is true, subject to many ifs and buts. 

Microwave rays, though not a form of dangerous ionizing radiation, vibrate molecules of some substances. Water and fat molecules are particularly sensitive to this, and their rigorous shaking and spinning produces heat. This property is used in microwave ovens to heat and cook food. This also explains why our skin would burn if exposed to microwave radiation. 

However, the burning from microwave rays would be insignificant when they fall on our skin in a very low concentration. The next section explains why rays being generated within microwave ovens are not likely to harm us.

These rays do leak from microwave ovens, and, thus, silently keep harming us.

Microwave ovens have safety mechanisms that do not allow microwave rays to leak in quantities that would be harmful to humans.  Two main safety features are: a, switching off of magnetron (the equipment that produces microwave rays) when the door is opened or there is an obstruction between the door and the cabinet, and b, the glass door being microwave-proof.

If a very low amount of microwave radiation leaks from the oven, it is too feeble to have a deleterious impact on our health. Yet, to err on the right side, it is advised that constantly looking inside the oven through the glass and being too near the oven for a long time be avoided. For the same reason, microwave oven should not be used when the door is damaged, or it does not switch off the oven when closed.

In one report floating on YouTube, it is said that these rays have been found to be harmful to foetus and therefore pregnant women must avoid microwave-cooked food. In one video, it is claimed that this fact is deliberately hidden from the general public. It is true that if microwaves are bombarded on a soft tissue (including foetus), they will damage the tissue. But no microwave rays remain in food after it is cooked, and to say that these enter the foetus from microwave-cooked food is to propagate a fallacy in the name of exposing a secret.

Microwaves, being unnatural and very strong, destroy micronutrients, such as vitamins, in the food.

The fact is that very fast cooking (for example, in a pressure cooker), and slow cooking for a very long time (for example, cooking of meat in some traditional dishes) can destroy many micronutrients and other useful natural chemicals much more than microwave cooking. 

It is also a fact that since microwave cooking does not need as much fat or water as some of the traditional methods of cooking need (for example, deep frying, boiling), it results in less nutrient loss. It has been found in studies that some micronutrients are preserved better in microwave cooking, especially when the cooking is done with less fat and water.

The notion that microwave cooking is unnatural while other forms of cooking are not, is fallacious. All forms of cooking are unnatural in one way or the other, as cooking of food is not a natural process used by animals. Among the traditional cooking methods, some are even weird, but we tend to ignore their unnaturalness. Cooking live animals, grilling, smoking, firing rum over cooked food and pouring liquid nitrogen over food- such ways of cooking are likely to produce chemicals unsuitable for human health.   

Another false logic to demonise microwave cooking is that food cooks inside-out in microwave cooking as against in traditional cooking. This unnatural cooking is supposed to suddenly produce extreme heat in the centre of food, causing food molecules to explode and give rise to toxic chemicals. As explained earlier, microwaves do not ionise atoms, do not break them apart (except that they break due to heat transferred to them by water or fat) or synthesize harmful chemicals. By the way, microwaves also heat foodstuff from outside inwards, much like in other ways of cooking. We sometimes find the core of crusty food items, nuts, etc. heating up while their surface remains cool; this happens due to the core being made of more watery or oily stuff and some other factors but not due to heating inside-out.

The notion of microwave cooking being unnatural has been extended even to call it against Ayurveda, the ancient medicine system of India. This is ludicrous, because those who invented and advanced Ayurveda millennia back could not have imagined that food could be cooked with the help of waves, so a caution against non-traditional ways of cooking in some ancient texts cannot be construed as a diktat against microwave cooking.

Another relevant point here. More than the heat, there are many other factors that result in destruction of food’s micronutrients and other useful chemicals. Highly acidic and alkaline substances, artificial taste enhancers and preservatives, other chemicals and the metals of cooking vessels act on these micronutrients, sometimes rendering them useless. 

Microwave rays can produce harmful substances in foods, causing serious diseases, including cancer.

Since ages, humans have become habitual of eating cooked food. That gives them the ability to eat food that they would otherwise not be able to digest. However, cooking can result in production of harmful substances, especially when food is cooked directly on flame (for example, broiling, tandoor, smoking) and in fats (for example, sautéing, stir-frying,deep frying). 

That holds good for microwave cooking too. If we overcook food in microwave ovens, it might produce harmful chemicals. On the other hand, in normal cooking with microwaves, there is much less chance of such chemicals arising. Some studies have found change in the texture of food on microwave cooking, but extra-ordinary production of harmful chemicals due to microwave cooking is not reported. 

All things considered, the notion that since microwave radiation is stronger than normal heat, it might result in carcinogenic and other dreaded chemicals is not based on facts. Some YouTubers, for seemingly championing the cause of Ayurveda and traditional medicine, discredit all modern technologies and spread rumours. One YouTuber, who appears regularly on TV channels and also runs an Ayurveda pharmacy, claims that food cooked in microwave ovens leads to serious diseases relating to endocrine glands (which produce hormones), and nervous and digestive systems. He and many other YouTubers claim that it also reduces immunity against infectious diseases, though no scientific study has proved that. 

There can be one reason microwave heating might actually harm our health, but that is due to the ease of heating that microwave provides as compared to normal heating, not due to the waves. Because of this, we are tempted to heat food even if that is not required, when microwave oven is around. When we heat already cooked food over and over, whether in a microwave oven or by other means, the chances of harmful chemicals arising in the food increase to that extent. 

In some studies on plants, microwave-treated food has been found to be very harmful.

The rumour seems to have started with an email that was spread sometime in 2010, in which two plants were shown growing side by side- one supposed to have been given microwaved water and the other, pure water. The email article shows, with the help of images, how the one that was given microwaved water became unhealthy and wilted, while the one irrigated with pure water grew well. The contents of the email were all made-up and the claim was proved wrong by setting up experiments, but the rumour still circulates as an evidence of microwaved water being harmful to plants. 

Microwave ovens have been banned in some advanced countries, including Germany and Japan.

There are such fake reports floating on the web and social media, propagated mainly by conspiracy theorists. In one report, it is said that microwave ovens have been banned in Germany, Japan and many other countries. The reason touted is another fake item- that research has established production of free radicals (which trigger formation of tumours and cancers) in microwave-cooked food due to break-down of oxygen atoms present in water and food. 

Microwave-safe packets can cause serious health problems.

This is a partly true statement.

It is a fact that the plastic itself and the additives used in producing microwave-safe plastic containers does not leech into food in one instance of heating. However, we tend to reuse the container and let the heated food rest in them, which can lead to leeching of harmful chemicals into our food. Using such containers repeatedly, keeping food in them for a long time, scrubbing them hard, and wear and tear can accelerate migration of harmful chemicals into food. Wrong handling of such containers in transit, such as keeping them in high temperature or under the sun, can also result in plastic contamination. In addition, it is also reported that sometimes sellers use unsafe plastic, while marking it as microwave-safe. 

Plastics and their additives are linked with hormonal disorders, obesity, diabetes and reproductive issues. In view of this, it is advised that heating food in microwave-safe plastic containers should be avoided.

Is it promotion of microwave ovens, or what?

This is the question that might trouble you after reading this article, more so if a doubt has been lingering in your mind about microwave cooking.

Let me assure you that the inferences drawn in this discussion are without fear or favour. Microwave cooking is as safe or unsafe as other ways of cooking. As explained above, microwave radiation does not come out of the oven and it does not remain in the cooked food. However, there might be a risk of leak of microwaves if the equipment is defective. Food cooked in microwave oven is safe and healthy, but overcooking and repeated heating in microwave can destroy its micronutrients as much as other wrong ways of cooking. The claims in the media, web and social media about harms caused by microwave cooking are mostly half-truths or fallacies being spread due to misconception or deliberate misinformation.

So, let us enjoy the benefits of microwave oven, and – like we do with all other tools – use it with care.


A video on ‘How microwave ovens work’, in Hindi, is linked here. You can also watch a video ‘Whether microwave destroys nutrients in food and produces cancer’ below. This, too, is in Hindi.


*Manoj Pandey is a former civil servant. He does not like to call himself a rationalist, but insists on scrutiny of apparent myths as well as what are supposed to be immutable scientific facts. He maintains a personal blog, Th_ink

Disclaimer: The views expressed in this article are the personal opinion of the author and do not reflect the views of which does not assume any responsibility for the same.


Please enter your comment!
Please enter your name here