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is it true that microwave ovens are bad because of the radiation it emits into the food? Answered

i am afraid to use the microwave oven much because overusing it can possibly cause health problems in the future because of the radiation that emits into the food.  So I mainly use toaster ovens.

should i be concerned, any experts in this field?  thank you.



Best Answer 7 years ago


The radiation emitted in the microwave range is considered non-ionizing, long story short, it doesn't have enough energy to chemically alter the food. *someone verify this for me*. This means that unless the food is made inedible/dangerous by heating by any means, microwaves will have no different effect on them.

What microwaves do is act on a somewhat unique property of water (and other) molecules: polariziation. since the hydrogens are offset from the central axis, the water molecule ends up with a 'more positive' and 'more negative' polarized side. In a very simplified nutshell, microwaves are just the right frequency to cause these molecules to 'vibrate' as it were, and they transfer this energy as heat into what you're trying to cook.

From wikipedia: "Long-term rodent studies to assess cancer risk have so far failed to identify any carcinogenicity from 2.45 GHz microwave radiation even with chronic exposure levels, i.e., large fraction of one's life span, far larger than humans are likely to encounter from any leaking ovens.[33][34] However, with the oven door open, the radiation may cause damage by heating; as with any cooking device"

So - it can physically hurt you, but not radiologically - Don't get burned!

Frollard wrote, "it doesn't have enough energy to chemically alter the food. *someone verify this for me*" That's technically incorrect, as you can deduce trivially from conservation laws.

The microwaves are tuned in frequency, as you say, to preferentially excite rovibrational states of water. That energy then transfers to the surrounding material as heat, which chemically alters the proteins and other molecules. If the microwaves didn't have sufficient energy, you wouldn't get enough heat to do the cooking.

The key is that the energy transfer is rapid and efficient, so that food cooks faster in a microwave oven than by most other means.

Thank you - I didn't phrase it how I meant without the clarifier in my other paragraph:

It can only do 'damage' with heat, same as other cooking methods.

*as steve says, they don't make the food radioactive either. Think of it this way - visible light is radiation, but you don't make something radioactive by shining light on it. Don't get me wrong, light can be damaging, and break down certain molecules (think ultraviolet and sunburns) but it still doesn't make the end result radioactive or dangerous where traditional heating wouldn't.

Do professional physicists count as "experts." Steve is one, and has given you the right answer (along with a number of non-physicists who know how to do research). I'm another.

The microwave radiation in the oven is tuned to match the rotational and vibrational states of water. So what it does is to "shake" the water molecules, heating them up.

You can do exactly the same thing with infrared radiation (i.e., the stuff your toaster oven generates), but it takes longer because the infrared isn't tuned to match the rotational/vibrational frequences.

Microwaves are not energetic enough to break chemical bonds directly, and are about nine orders of magnitude (that's one billionth) too low in energy to do anything "nuclear" (so no induced radioactivity).

If you're afraid of what the microwave oven does to food, then you should be equally afraid of toaster ovens, stoves, and campfires.

to your last sentence: "..and especially the sun..."

Except that the sun does produce ionizing radiation, and lots of non-ionizing radiation which is still energetic enough to do chemical (and genetic) damage. I left it out of the discussion on purpose.

apples and organges, I know - but it made for a striking case how food is safer in a microwave than cooked in the sun.

Yes, indeed! Playing the fear-monger among ignorant ecofreaks is like shooting fish in a barrel, or maybe more like shooting fish in a salmon ladder :-)


Another urban myth shot down! :-) I would be more worried about getting a good balanced diet - eating enough vegetables and fruit, getting enough exercise and keeping weight, blood pressure and general health in good order.

There is radiation all around use - TV , Radio waves, Microwaves, mobile phones.

Pollution abounds in the sea, land and air, some intentional and some not.

Our food is laced with a cocktail of chemicals to make the animals/crop grow faster or last longer on the shelf.

Cooking it the microwave is the least of your problems!

Microwaves ovens use radiowaves to heat the food, not ionising radiation. There is NO sense in which the food is "radioactive".