Some say that the radiation inside a microwave oven is bad for our health. And that it’s bad for our food. It’s uncertain from where these contentions originate exactly. Even though the introduction of the microwave oven1They were called ‘electronic ovens’. in our homes took place in the 1960s, among some, they never got rid of their unhealthy reputation entirely. In this article, we will have a look at what its radiation is and how that influences food and vitamins. We will then proceed to answer the question: Is microwave oven radiation unhealthy?
The word ‘radiation’
In physics, ‘radiation’ is the emission or transmission of energy in the form of waves or ‘particles’. Not all radiation is a health hazard to our species as we have evolved to be immune in most cases. Radiation emitted by nuclear reactors is dangerous. However, it may not surprise you that we have evolved to withstand the radiation of tea lights.
While society generally might not care about what physics says ‘radiation’ means, this is what we’re going to be using throughout this article.
Radiation is not always dangerous. There are more things in everyday life than you might think which are forms of radiation.
Some examples of sources of radiation: bananas (which are naturally radioactive), magnets, candle sticks, central heating, club and stage lights, any light source for that matter, including your bathroom light, human bodies, microwave ovens, the Sun, the uranium and plutonium rods of a nuclear plant, and furthermore, anything you can see with your eyes either emits or reflects radiation, right here, right now.
Just look straight into the eyes of your partner, or friend with merits, lying next to you the next morning: whether you want to or not, they have been literally gushing their radiation all over your body, right here, and are still, right now, the whole time. And not in any spiritual or venereal sense, no no, you have been and are being exposed to actual spurts of electromagnetic radiation discharging from their bodies2Infrared, mostly. Note that our bodies are also radioactive. We emit ‘particle’ radiation too. On average, about 5000 of our atomic nuclei decay every second (5000 Bq) and emit radioactive radiation., at energy levels literally more than a hundred thousand times higher than microwave oven radiation.
In fact, in all the examples above, it’s the same type of radiation as microwave oven radiation, called electromagnetic radiation. The difference is that the examples are more than a hundred thousand times more energetic than microwave oven radiation. Except for a big chunk of the Sun’s radiation, and uranium and plutonium rods. Those entail dangerous forms of ionising radiation, and involve more than just the electromagnetic kind.
The dangerous form of radiation is called ionising radiation. This is the type of radiation many people think of when they hear the word ‘radiation’. Microwave oven radiation isn’t that.
If incoming radiation has so much energy that it strips one or more electrons away from their nucleus, we call this ionising radiation. An atom which has lost one or more electrons, we consider to be ionised, and so, we now call it an ion.
Why is this dangerous? Well, our bodies are made of large strings and knots of intertwined atoms. Our skin, organs, cells, DNA—it’s all made up of trillions of atoms. Those atoms are only able to form these large chains and knots because their electrons keep them together this way.
Thus, if ionising radiation strips away those electrons from their nucleus, then our molecules, cells, DNA—it all falls apart. And especially damage to our DNA is dangerous as this could develop into cancerous growth. Fortunately, our body has evolved to possess certain superpowers, if you will, enabling it to repair damaged cells and even DNA to an astonishing degree.
Sadly, there are limits. A sufficient blast of ionising radiation may cause damage beyond our bodies’ repair capabilities and thereby may be the cause for cancer.
Ionising radiation breaks down atoms, thus molecules, thus organic cells. When our body’s repair mechanism is overwhelmed by the amount of ionisation, this may eventually lead to cancer and organ failure. Microwave oven radiation, however, is not ionising at all. Far from it. It is simply not energetic enough. Not by a stretch.
Examples of ionising radiation are:
- subatomic particle radiation: such as protons, neutrons, separate or combined to an atomic nucleus3Also known as alpha particles. as well as electrons and positrons4Also known as beta particles. flying about, aimed at your general direction;
- high-energy electromagnetic radiation: cosmic rays, gamma rays5This is what Dr Bruce Banner was exposed to, turning him into what we call a Hulk. But please, don’t try this yourself. Most likely, you’ll die. At best, you might end up looking like former KGB agent Emil Blonsky or General Thaddeus Ross. If you’re unfamiliar with their tragic fates: Universal Misery., X-rays6In hospitals, you will receive much less the amount of X-ray radiation than would be dangerous. Your body is capable of repairing any damage, in this case. It still means that one must be careful, hence, only highly-qualified medical personnel should administer X-ray doses., the higher-energy UV-light.
Microwave oven radiation is electromagnetic radiation. What is the latter then? In physics, we have the most successful of theories called quantum electrodynamics (QED), which arose in the 1930s. Do watch these amazing, very accessible videos of the genius and Nobel laureate Richard Feynman, who brought major contributions to QED. It’s the first theory within a larger physical framework called quantum field theory (QFT). In short, without QED, we wouldn’t have had electromagnetism-based technology such as microprocessors—which means we wouldn’t have had TVs, computers, mobile phones, and internet. To understand the theory is to make a few mental steps. In Why, exactly, do glass and liquids refract light?, we’ve mentioned QFT already. We paraphrase the essence down below.
Space throughout the entire observable Universe is filled with three-dimensional fields. In fact, fields are a property of space. Space without fields does not exist. With space come fields.
There are many fields. Two of these fields are the electromagnetic field and the electron field.
We perceive oscillations at specific frequencies in the electromagnetic field as photons, ‘particles’ of light, if you will, sometimes visible light but most of the time it’s invisible light.
We perceive oscillations at specific frequencies in the electron field as electrons. If we measure them—interact with them using an electric probe in the lab for instance—we perceive them as ‘particles’. Usually, we speak about them as ‘particles’, even though they’re not.
Electrons influence the electromagnetic field. The latter influences electrons in return. Photons are oscillating parts of the electromagnetic field, and so, electrons influence photons, while photons influence electrons. However, electrons are only influenced by photons when the latter have specific energy values, not just any energy value.
Photons, or, the electromagnetic field disturbances caused by a microwave oven, which we call ‘radiation’, do not have the correct energy value to ionise the atoms in our body.
Luckily, photons emitted by the person lying next to you don’t have the correct energy value to destroy our atoms either, nor do the regular lights in our home, even though they carry a hundred thousand times more energy than those of a microwave oven.
All this is perfectly calculable. Because maths and physics.
How do we know?
Max Planck, a German theoretical physicist (1858-1947), found a way to calculate the energy values for photons. Einstein subsequently used Planck’s formula to come up with another formula allowing us to calculate if atoms would become ionised by certain forms of radiation. In The formula that got Albert Einstein the Nobel Prize and should stop us getting sunburn all the time, we discuss Einstein’s groundbreaking work in quantum mechanics which would later develop to become quantum electrodynamics (QED). Warning: mathematical equations are given in that article.
And so, after many more contributions by really clever people, the fascinating branch of science arose through which we are now able to harness the power of electromagnetic radiation, including that of the microwave oven as well as, incidentally, radio signals, TV signals, Wi-Fi, and mobile phone signals.
If you want to know where in the ‘spectrum of danger’ microwave oven radiation lies, have a look at this diagram. Hint: if radiation in a microwave oven were dangerous, then the lights in your toilet would liquidate you instantly to a warm, sliding, sneakers-covering pulp of mashed guts, lung pudding, and brain leftovers. Also, Planck, Einstein, and others, would be turning over in their graves.
Knowing this, the natural thing to ask is, what about all the heat? If microwave oven radiation is really that low-energy, how does it manage to cook my food boiling hot? The answer is friction.
Remember that time when you bent a piece of steel wire back and forth quickly for a while? And that the bend eventually became very hot? That’s because you had been moving many molecules back and forth quickly enough to have them heat up the wire due to friction. You don’t need life-threatening amounts of energy—merely the energy of your arms—to make something really, really hot. Microwave radiation does that mainly with the water molecules in food.
Under the influence of the electromagnetic field inside the microwave, the slightly polarised water molecules rotate back and forth about 2 400 000 000 times per second. Friction with their surroundings cause heat.
It’s like rubbing your hands together the same number of times per second, which entails friction and causes heat. This is why it’s easier to heat up solid food in the microwave oven than liquids, such as a cup of water: in the latter, water molecules experience less friction than in the first.
The radiation does nothing to the composition of the atoms. It merely causes molecules to move. Just as a flame does. Or a conventional oven. Making molecules move, that’s all there is to it.
This also means that you shouldn’t put your hand in an operating microwave oven. Your molecules will start moving too, just like in a conventional oven or when you would put your hands into a flame on the hob. Though, admittedly, in a microwave oven that would mostly only be your water molecules, while in a conventional oven or on the hob, all of your molecules are affected.
Does microwave oven radiation destroy vitamins? As stated before, the radiation isn’t ionising, so it does not destroy vitamins. Heat does, however. Just as flames and conventional ovens heat up food and through that heat destroy vitamins, so does radiation. Not because of the radiation but because of simple heat.
If microwave oven radiation did destroy vitamins, then the light hanging over your dinner table should obliterate the entire dish in an instant. That would be overdoing the concept of having a quick meal, somewhat.
Here’s a silver lining. The longer food is exposed to heat, the more vitamins are destroyed. So, if there would be a means to heat food as quickly as possible, less vitamins would be destroyed. It might just be that, depending on all kinds of settings and situations, heating food quickly inside an efficient microwave oven spares more vitamins than a slow burn on the stove.
Moreover, cooking food in a pot in its liquids and then throwing away the liquids equals throwing away the dissolved vitamins in those liquids. This happens a lot while cooking on a conventional hob. In a microwave oven, however, everything stays on the same plate. So, even if vitamins have dissolved in the food’s liquid, you’d still have them on your plate.
Lastly, while microwave ovens don’t emit radiation that is carcinogenic, food itself may very well be, especially when it’s burnt. So, particularly when cooking on the flames and in a conventional oven: don’t burn your food. You know this. Don’t burn it to a crisp and then eat it.
Incidentally, microwave oven radiation is very unlikely to burn food on a plate7Which is why many don’t like it since, more often than not, a little bit of that browned-burnt-y flavour does taste good..
Is microwave oven radiation unhealthy?
Courtesy of quantum physics, microwave oven radiation is not unhealthy and by itself, it doesn’t destroy vitamins (heat does). There is also no residual effect that might be dangerous: it’s like switching the light on and off, only a hundred thousand times less energetic than light. One might mix things up with the residual effect of a nuclear bomb or a nuclear disaster. This is due to the billions of heavy atomic nuclei having been hurled into the environment which in turn emit ionising radiation for thousands of years. Microwave ovens don’t hurl atomic nuclei into your food. That would have been deadly, indeed.
Any text online, in books or magazines, stating otherwise is basically fighting against the quantum mechanical facts of the Universe. And a grumpy Einstein. In which case, other forces and motivations must have been at play in stating these uninformed propositions.
So, if someone is telling you microwave ovens are unhealthy, ask them for the exact quantum mechanical equations supporting their claim. Sorry but it is what it is, and it is simply this Universe. If quantum mechanics weren’t correct, they’d have never been able to read their uninformed online source, anyway. Computers wouldn’t work. Their mobile phone would be nothing more than a fancy brick. Internet would never have existed. They would never be able to spread false rumours online about microwave ovens if physics were incorrect. Heck, they themselves wouldn’t even exist.
By the same science, however, do watch out for the Sun’s UV-light this summer. And avoid at all cost, cosmic rays, gamma rays, and particle beams8Unless exposure takes place briefly, as conducted by awesome and life-saving medical professionals., so, whatever you do, do not stroll outside your international space station without a protective suit. And don’t eat yellowcake. Ever. Instead, radiate some green beans in a microwave oven. And eat a radioactive banana. Much healthier.
@kjrunia is reading mathematics and theoretical physics (final year) in England, at The Open University, Walton Hall, Milton Keynes. He also works on coding for the Mars Rover of the university’s Planetary Robotics Team.