Is food cooked in Microwave Ovens dangerous? An experiment

If you’re on Facebook I’m sure you’ve seen the latest round of scare stories about microwaves.  Typically, they show a series of photos with the following narrative as below:

“Below is a science fair project that my granddaughter did for 2006. In it she took filtered water and divided it into two parts. The first part she heated to boiling in a pan on the stove, and the second part she heated to boiling in a microwave. Then after cooling she used the water to water two identical plants to see if there would be any difference in the growth between the normal boiled water and the water boiled in a microwave. She was thinking that the structure or energy of the water may be compromised by microwave. As it turned out, even she was amazed at the difference.  Below are the pictures that were actually submitted with the project.”

I was trained as an experimental social psychologist so immediately I was suspicious of the “results.”  There were just too many confounding variables, the biggest one being that no two plants react the same to pruning and you just can’t identically prune plants (I know this from experience!!).  It would be better to start from seeds planted under controlled conditions into identical soils.  Even then, some seeds are duds no matter how good the condition, so you would need to plant multiple seeds to give the hypothesis a fair test.

I found the original site of this experiment here and they actually pointed out the best explanation (in my opinion) for the plants’ different responses to different types of water.  Turns out they boiled the microwaved water in plastic, which is a known health hazard.  That is, boiled water into any plastic container, microwaved or not, is dangerous because chemicals from the plastic can leach into the water.

But still, I was curious.  We regularly use our microwave and if water boiled in it really killed plants, I wanted to know.  So, here’s what I did.  I ran a 2 x 2 experiment comparing growth of peas from seeds (a) planted in Hygrosoil (a Zambian potting soil kind of like Miracle Grow potting soil) OR our very own homemade compost, and (b) watered them with microwaved boiled water OR electric stove boiled water.  I used original tap water and boiled it in a ceramic container, arrayed the plants along the exact same window with the exact same sun exposure, and watered them the same amount each day.  Here’s the design.



Microwaved Boiled Water

3 pea seeds

3 pea seeds

Oventop Boiled Water

3 pea seeds

3 pea seeds

I selected 12 seeds that looked as similar as possible.


According to the package, the seeds were to germinate in 8-12 days.

I planted the seeds on April 26.


Would you believe that just five days later (on May 1), the Hygrosoil-Microwaved Water pot has sprouted already!  (Remember, they’re not supposed to sprout until days 8-12.)  Here are the two sets of pots by soil side-by-side on May 1:

It’s hard to see the growth, so here are close-ups of each pot on May 1, which was day 5.  You can see that the stems of the peas are already rising by the evening of May 1 in the microwaved water pot (left).  On the right, in the boiled water pot, you can see the peas are just starting to sprout, so they’re about half a day behind the microwaved water pot (this morning there were no sprouts in that pot).









Nothing’s happening yet in the compost soil pots.









I was actually quite relieved to see these results, though it’s still early in the experiment.  I’ll continue to keep you posted as the growth continues.  What I gather from these results is that microwaved water is okay, as long as it’s not microwaved in plastic.  Avoid putting hot things in plastic!

Given we live in a synchronous universe, wouldn’t you know it that right after I discovered the growth in the microwaved water pot this morning, I sat down for breakfast to read an article from Consumer Reports on Health and there featured front and center was an article on health myths.  One of the health myths it tested was if microwaved food lost nutrients during the cooking process.  Here’s what they found:

Microwaved food may retain vitamins BETTER than stovetop-cooked food.  That’s because the microwave zaps it quickly and without much water.  One study found that spinach retained only 77 percent of the B-vitamin folate when cooked on a stove — but retained ALL of its folate when cooked in a microwave.” (capitalizations in original)

Regarding the original Facebook posting, it turns out I wasn’t the only one who was skeptical.

The rumor-checking site was suspicious too and ran their own experiment here.  Turns out their experiment had similar results as mine – the plants watered with microwaved water grew just fine and sometimes better when compared to plants watered with other sources!

Here’s what they did:

“We started out with three each of three different types of plants: one member of each set was given water than had been boiled on a gas stove, water that had been boiled in a microwave oven, or water that had not been boiled at all.  All the water used in the experiment came from the same source, the same vessel was used for boiling water both on the stove and in the microwave, and all three types of water were stored in identical containers.  The water given to all of the plants was at room temperature…As evidenced by the photos below…all three plants in each set fairly thrived.  When Barbara asked me to indicate (blindly) which plant in each set I thought had fared the best, in two cases I selected plants that had been given microwave-boiled water, and in one case I selected a plant that had been given unboiled water.”

So, there you have it!  So far, on day 5, it would seem that microwaved water does not harm plants, and in fact, leads to plants that germinate more quickly.  I’ll update you on the experiment in a week or so.  Until then, it appears that microwaving in glass dishes only is not detrimental to one’s health.  We’ll see if that claim holds in a month!


About Kimm X Jayne

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2 Responses to Is food cooked in Microwave Ovens dangerous? An experiment

  1. Maureen Witte says:

    Love it!

  2. Kimm X Jayne says:

    I didn’t close the comments here and can’t figure out why they’re closed! Please respond on another page if you have a comment about this page.

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