Wednesday, May 11, 2005

Apple #68: Microwave Ovens


Not long ago, a friend of mine said she hardly ever uses her microwave anymore because "microwaves destroy all the nutrients" in food. She said when she's tempted to use her microwave, she asks herself, "Do I want to get any nutritional value out of this?" and then uses her oven or stove instead.

This sounded to me like some kind of overly suspicious urban legend, but I couldn't get it out of my head, especially when I was about to microwave something. So I decided to check it out. What I found is that there are a lot of people who say that microwaves cause big problems in food. There are also a lot of other people -- scientists and people who love their microwave ovens -- who say, "Pah!"
  • Microwaves use magnetrons, which use magentic and electrical fields to produce micro wavelength radiation. This radiation is what affects or "zaps" your food.
  • The wave energy is constantly changing polarity, with every cycle of the wave. This happens billions of times in a second. Since the waves are bombarding your food like crazy, this is also making the molecules in your food change polarity just as rapidly. (For a graphic that helps explain this, see this page.)
  • So the food molecules are flopping back and forth, billions of times per second. This creates all kinds of agitation and is what heats the food. According to those who don't like microwaves, it is also this agitation that breaks down the molecules, or sometimes deforms them, or may even tear them apart. They say this is how the structure of vitamins and enzymes in the food get destroyed.
  • All heating processes break down the structure of food, but many people say that microwaves cause the most damage. Studies have been cited that say that between 90% and 97% of the nutrients get destroyed in the microwaving process.
  • On the other hand, the FDA says that microwave ovens can be better than conventional cooking because they heat the food faster. If foods are heated slowly, or kept warm for long periods of time, they can lose nutritional value, so because a microwave works faster, it is therefore better. The FDA also says it's a lot harder to burn the food in a microwave, and you get much more even cooking.
  • The Washington State Department of Health and other governmental/scientific overseeing organizations say it's simply not true that microwaves destroy the nutrients in food.
  • In general, hard-core scientists dismiss people's worries about microwave ovens as coming from a lack of understanding about how microwaves work. Microwaves use non-ionizing radiation, which means it's not the kind of radiation like X-rays, which can cause chemical damage in molecules. Scientists say, because microwaves are non-ionizing (and because your microwave oven is lined with metal, which will make the rays bounce back into the oven), you don't have to worry about how close you stand to your microwave. You also don't have to worry about your food emitting psycho-crazy waves when you take it out of the microwave.
  • One wrinkle in scientists' certainty, though, came in the late 1980's, when chemists started trying out the microwaves that they had been using to re-heat their food on their chemistry experiments. They discovered that processes that would otherwise take hours or even days could be completed in minutes in the microwave, and often without the heretofore necessary super-duper solvents.
  • This started a branch of chemistry known as "microwave chemistry" because the scientists discovered that the microwaves produced unpredictable results. They also realized they didn't always understand why the microwaves were having the effects they were having.
I still have some questions, and the information I've found so far is contradictory enough, I want to keep looking into this further. More soon when I get something more definitive.

In the meantime, here's a really great site about all kinds of crazy things you can make happen in a microwave, like making ordinary tap water explode, or making a lit candle spew lightning, or even blowing up marshmallow Peeps.

Healing Daily, "Should you be concerned about cooking your food using a microwave oven?"
News Target commentary, "Microwaving your veggies destroys 97% of nutrients like antioxidants," date unknown
Marion Wild, "Are microwave ovens a source of danger?" reprinted at Cure Zone, Health chat, "Microwave Cooking -- Just Say No!"
US FDA, Performance Standards for Microwave and Radio Frequency Emitting Products, part 1030
Washington State Department of Health, Division of Environmental Health, Office of Radiation Protection, Microwave Oven Radiation
The Straight Dope, "Does microwaving kill nutrients in food? Is microwaving safe?" May 6, 2005
How Things Work,, Microwave ovens, Microwave Oven Repair and Care

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