I used to be that person.
I believed that microwaves are destroying the nutritional value of foods because everyone around was saying so.
But nobody bothered to check if it’s actually true.
So I did it few years ago and quickly changed my mind on microwaves.
And now I’m going to share this knowledge with you. Let’s go!
How does microwave oven work?
It uses a type of electromagnetic radiation – microwaves which have heating capabilities discovered during II World War. Imagine running a high voltage within a copper tube and a copper rod inside that tube. The space between the rod and the tube allows electrons to move outwards in a spiral pattern. The tube is placed in electromagnetic field what makes the electrons to hit the edges of the tube creating vibrations which are – MICROWAVES!
The microwaves inside the oven are absorbed by water, fat and carbohydrate molecules causing them to shake and create heat. The conduction of that heat happens much quicker than when using conventional oven simply because the microwaves penetrate the food deeper than heat making more particles to move at the same time.
Microwave radiation is a type of non-ionising radiation. It is safe meaning that it does excite particles to make them wiggle but does not carry enough energy to ionize – remove electron from an atom of molecule. The ionising radiation such as x-rays or gamma rays are hazardous but is much more powerful than the one coming out of your microwave.
What about the nutritional value of the foods cooked in a microwave?
There is plenty of scientific evidence pointing out on the fact that microwaving food is better than boiling or baking. If you take the micro- and macronutrient levels of the raw vegetables as the base level, the way of minimalizing any loses is to cook them in the fastest way possible. That’s why microwaving (when done correctly) is a convenient and quick way of preparing your meals. Steaming is as good and, in some cases, even better in maintaining the nutritious content, while boiling takes much longer and some of the valuable molecules are left in water which is often emptied into the sink after boiling.
Using microwave makes nutrients become more digestible by our bodies – carotenoids in carrots and tomatoes or biotin in the eggs. Studies also show that the antioxidants are better retained in microwaved foods when compared to stove cooked (1).
Spinach – when boiled loses 70% of folic acid, microwaved retains 90% of it.
Legumes – microwaving them after soaking in water preserves the nutrients much better than boiling (2).
Oat and bran flakes – show the highest antioxidant and starch levels after 3min of microwaving when compared to stove cooking.
Antioxidants prevent cell damage and ageing processes in our bodies. But what about starch levels? All carbohydrate (sugar-based) foods have glycaemic index (GI) which shows the ratio of simple sugars to complex sugars. If you want to gradually increase and maintain your energy levels for longer period, you want to eat more low GI foods. High GI meals, full of simple sugars will give you a rapid spike of glucose in your blood followed by a massive crash and cravings of more sweets in a short time. When cooking the GI of foods is going to change, thus we should always take into account that even low GI raw oats may become high in simple sugars after cooking. Microwaving oats and bran flakes maintains low GI: low glucose and high starch levels (3).
Vitamins – the overall retention of vitamins in microwaved foods is higher than in stove cooked ones. In both cases, adding lemon juice is proven to help retaining more vit. D3.(4)
Remember!
While microwaving is better than boiling, it’s important to do it correctly. Do not add too much water while preparing vegetables, since it will have a similar to boiling outcome. Aim to decrease cooking time as much as possible and use tight lids to create a steamer-like effect. Also, take into account that the ready meals are not healthy and heating them up in a microwave won’t change the fact that they are highly processed foods with low nutritional value.
Happy cooking ! 🙂
motivelina.com 
Hi Ewelina, This is very interesting, but I have a question. I have seen a lot of this discussed on the internet, but not by truly reputable sources, just people who do a home experiment and post it to YouTube, for example. Anyway, have you heard of the water plant microwave experiment in which folks microwaved water to water a plant and did the same with a second plant but instead used regular water? It shows that the microwaved water actually killed the plant. How does this play a role in what you’ve said above?
Jess || https://www.learningfromstrangers.com
PolubieniePolubienie
Hi Jess. This is a really interesting question actually! I will try to break it down a bit for you. In order for the experiment to have any scientific value it needs to be designed in a certain way (I guess most of these home-youtube experiments aren’t but please correct me if I’m wrong). Firstly, all plants need to be the same, preferably of the same „age” too. Secondly you need at least 3 plants per each water type (in this case 6 per experiment in total) and you need to be able to repeat that same experiment 5 times afterwards (=30 plants in total). Then you need to make sure the microwaved water is exactly the same temperature as the tap water while given to the plant. All plants would need to be stored in the same room, with the same reach of sunlight and room temperature so the only variable you change is the water source. If a botanist looked into that design there are probably more things to be added but let’s try to keep it simple.
Why does it have to be so complicated (initially we had only two plants and water)? To avoid the statistical errors. Plant may simply die by chance and by repeating the experiment certain amount of times we make sure there is a „dying by chance” threshold in two water treatments. If in this perfect experiment a significant amount of plants die from microwaved water, then the result is not an anecdote anymore but a scientific outcome, which should be investigated further.
From the physics point of view, there is no difference in water mineral content or its other properties while heated by kettle, on a stove or a microwave. In my opinion most commonly made mistakes would be to keep plants on different windows so the sunlight becomes another unmeasured variable or after boiling water in the microwave people do not let it to cool down properly (warm water kills most plants). Let me know if that helps 🙂
PolubieniePolubienie
WOW yes! Very interesting. Thank you for the layman’s breakdown. 🤓
PolubieniePolubienie
You’re welcome 🙂
PolubieniePolubienie
Yes! This information is very interesting & would also be a great blog post
PolubieniePolubienie
I’m happy you found it interesting 🙂 I may start writing posts explaining the issues with homemade youtube experiments, that’s a great idea 🤔
PolubieniePolubienie
Hi Jess. This is a really interesting question actually! I will try to break it down a bit for you. In order for the experiment to have any scientific value it needs to be designed in a certain way (I guess most of these home-youtube experiments aren’t but please correct me if I’m wrong). Firstly, all plants need to be the same, preferably of the same „age” too. Secondly you need at least 3 plants per each water type (in this case 6 per experiment in total) and you need to be able to repeat that same experiment 5 times afterwards (=30 plants in total). Then you need to make sure the microwaved water is exactly the same temperature as the tap water while given to the plant. All plants would need to be stored in the same room, with the same reach of sunlight and room temperature so the only variable you change is the water source. If a botanist looked into that design there are probably more things to be added but let’s try to keep it simple.
Why does it have to be so complicated (initially we had only two plants and water)? To avoid the statistical errors. Plant may simply die by chance and by repeating the experiment certain amount of times we make sure there is a „dying by chance” threshold in two water treatments. If in this perfect experiment a significant amount of plants die from microwaved water, then the result is not an anecdote anymore but a scientific outcome, which should be investigated further.
From the physics point of view, there is no difference in water mineral content or its other properties while heated by kettle, on a stove or a microwave. In my opinion most commonly made mistakes would be to keep plants on different windows so the sunlight becomes another unmeasured variable or after boiling water in the microwave people do not let it to cool down properly (warm water kills most plants).
PolubieniePolubienie
When I first say the post title, I just knew I was doomed. However, I find the information to be very helpful in my current living arrangements. I cook from a microwave, electric skillet, toaster oven & griddle. It is always best to do research because I was praying I was not doing any harm to myself by using the tools I have available for me at this time. Thanks so much for the clarification!
Ms.Flo
PolubieniePolubienie
Thank you for your comment! I’m very happy that the post was useful and made you stop worrying about your health. Have a nice day!
PolubieniePolubienie
Wow I did not know any of that!
PolubieniePolubienie
Good to know you learnt something new today 🙂
PolubieniePolubienie