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)
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 ! 🙂