To microwave or not? The health impacts.
To microwave or not? What impact does this have on our long-term health and well-being?
I love my microwave. Well, I did when I lived in Brisbane. It melted things and warmed things and made life easier when, once again, there was nothing defrosted to eat. For years I had heard microwaves were bad for you, but honestly, I didn’t look into it, just in case it was true, and I lost my kitchen friend.
Then the kids grew up and we moved to Adelaide. Could we make life simpler and healthier? Could we do without the microwave? Would the pain be worth the gain? I have always secretly admired those who do not use microwaves, somehow, they seem more organised and skilled than me! So maybe here was my chance to do without one. Maybe the organisational skills would rub off? Hmm, maybe not, but I thought I would research anyway, because I was curious.
What are the main concerns about microwave ovens?
- Radiation makes food unsafe to eat
- Off-gassing from plastics used in microwaves is dangerous
- Nutritional value in foods is decreased compared to other forms of cooking
- The radiation from microwaves themselves is dangerous
1. Microwaves make food unsafe.
It turns out that microwaves do not make your food radioactive!
The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) state microwaves do not make food radioactive as they use non-iodising radiation which cannot split atoms, so is not radioactive. There was no real hint of anything else in my research, so I parked that idea and went to the next.
2. Chemicals leached from plastics used in microwaves are bad for you.
True.
We know that heating plastics means chemicals leak out and can disrupt your endocrine or hormonal system. Here is an article explaining how this happens.
If we know this why are plastics still being used? They are everywhere and make our lives so much easier. Imagine life without them! We often ignore what is bad for us in favour of convenience.
Still surprised few people know this? The next part of the story is the varied response to plastics. The relationship between the amount of chemical exposure and the risk of hormone disruption is non-linear (an increased dose does not mean an increased effect). This means that there is no safe level of exposure. Multiple studies have shown that low-level exposure is where the greatest component of damage happens.
This adds to the toxic load we are all exposed to and may cause a tipping point where health crashes. None of us know where our tipping point is, so the less we tip in, the greater the chance our health will remain stable.
No worries you think, I can use a glass container. Good idea, just be aware that even if you use a glass container, steam from the food hitting a plastic lid, to stop splatter, will still leach chemicals.
My thoughts – try and avoid plastics even if you microwave.
Beyond that, glass can be recycled, plastic not so much, so why not try a glass container?
3. Nutrition is lost from food when cooked in a microwave oven.
Seems the jury is out.
Most microwave critics cite a 2003 study that shows microwaving broccoli for various time lengths removes on average 97% of the flavonoids (plant compounds with anti-inflammatory benefits), 30% more than boiling.
A more recent study from 2019 concluded that microwaving and steaming resulted in less flavonoid loss than boiling when comparing shorter cooking times. However, they were unable to extrapolate to other vegetables as nutrients are bound differently in each vegetable and possibly differently in organic v non-organic vegetables.
So how do we summarise this?
The less we cook vegetables, the more nutrients remain in the food, regardless of the style of cooking. There will always be exceptions to this rule, and without individual studies on every vegetable known, we just have to go with what feels right.
My assumption from these studies would be that microwaving most veg in your glass container would be reasonable if you don’t add more than a spoon of water and keep them crisp. However, I would favour steaming over microwaving if this is available to you.
Also, keep in mind that the 2019 study was on very short cooking times. When we reheat in the microwave we use it for much longer periods of time. The 2003 findings will likely hold true in this scenario, however, there is no science to confirm or deny this issue.
The radiation from microwaves is dangerous
Opinions vary on this one.
Firstly, how do microwaves work?
In summary, they produce non-iodising radiation or electromagnetic frequency (EMF) waves that bounce around the metal box of the microwave. The metal lining stops the radiation from leaving but allows the rays to penetrate the food and container it is in. The waves cause water molecules to vibrate, the faster they vibrate, the more heat is created. If your microwave is solid and the door stays shut, then according to ARPANSA you are safe. However this seems to also come with a caveat that you should stay 30cm away from the microwave, and if seals are not great, or the microwave is old, then some radiation could escape. The official line seems to be that such small amounts should be safe, as it is unlikely that much escapes in the first place.
Given the non-linear effects of plastic leaching, I wasn’t convinced that this small amount of possible escape was as harmless as it was made out to be. I went to the science papers and found this Microwave Radiation and the Brain: Mechanisms, Current Status, and Future Prospects.
It is an excellent article that balances the pros and cons of radiation and how it may benefit medical treatments and yet can also cause damage to our bodies. The illustration below shows how microwaves fit into the EMF soup that we live in. Much like plastics, the devices that emit EMFs are everywhere and so useful that it is hard to imagine life without them.
To be fair to the microwave oven, the rays that may escape from it are at the edge of the frequencies that may cause cellular damage.
Figure 1 – Depiction of daily commercial and household radiation sources with corresponding operational frequency ranges.
What does the radiation do to us? The most common effect is to cause oxidative stress and breaks in the DNA in our cells. This can lead to cancer progression and brain damage as shown in the illustration below. Please bear in mind that when they talk about microwave radiation, the authors are including all forms of EMF shown above. Microwave ovens are just one source.
Figure 6 – Representation of microwave radiation effects on the brain. Microwave radiation induces protein damage in neurons, changes mitochondrial activity by influencing the formation of ROS and ATP levels, and causes breaks in single- and double-strained DNA, which leads to brain dysfunction and declines in spatial memory.
What does this paper suggest?
More studies to look at which frequencies do what to our bodies.
In conclusion, microwave radiation should not leach out of your microwave, though it is possible. If you stay away from the microwave whilst in use, your potential exposure should be less. We live in a sea of radiation, so the less we expose ourselves the lower the chance we will damage our DNA. Microwaves contribute less to this soup than your phone or computer does.
In summary, what do we know to be true about microwave ovens?
Microwave ovens do not make food radioactive, though they could leak radiation. Radiation in this form can cause oxidative stress in your body leading to DNA damage. Using a microwave oven will not leach nutrients from food if heated for a very short period of time. Heating food in any way in plastic of any sort will leach out chemicals that do affect your body’s endocrine system.
What is my advice?
Try not to use a microwave wherever possible. If you do, then definitely use glass containers regardless of what is stated on the plastic container.
When using the microwave stay 30cm away and don’t stare into the abysss hoping it will make it cook faster!
And heat food for the shortest time possible.
And finally, what did we do with our microwave?
We bought a microwave. We did not buy a second-hand one in case it leaked more. It sat in the box for 3 weeks while we pondered. And then we needed to heat up a heat pack for an injury. We opened the box.
Longer term I will try really, really hard not to use it. We will definitely not be using plastic in it. I will try and reheat on the stove more frequently and am looking at buying the old double boiler steamer system for veges. That is something that can be found second-hand. I was using the thermomix, which steams beautifully – but that is in plastic!
And you may notice the change in I and we. We have differing opinions on how important this one variant may be, within the soup we live in. Yet to be reconciled.