Friday, May 13, 2005

Apple #69: Microwave Ovens II


I've been doing some more reading because I really want to know if microwave ovens are screwing up my food or even my health in some way. My biggest question is about whether the action of heating food in a microwave damages the food to such a degree that your body can get no nutritional value from it, or if it even somehow renders the food hazardous to you.

What I've learned is that when a microwave heats food, it does so by changing the polarity of the molecules in the food billions of times per second. This results in changes to the molecules, changes that are called "structural isomerism." This means that the molecule keeps the same components, but everything in the molecule gets rearranged. When a molecule gets rearranged like this, it can have very different properties as a result, but not necessarily.

The websites that say microwaves are dangerous all say that the resulting structural isomerism is always bad, and that the food is therefore impaired in quality, sometimes drastically so. The scientific websites I've found don't really address this question directly.

The afraid-of-microwaves websites also keep telling the same anecdotes as evidence, over and over. I keep seeing the story about how one paper published in the 1980s said that microwaving breast milk changes the milk slightly. Exactly how the milk gets changed is where people get fuzzy on the details. There's also the story that gets told and retold of how in 1991 a nurse microwaved blood for a transfusion to warm it before injecting it into her patient, and the patient died. The actual cause of death was not linked directly to this microwaved transfusion; nonetheless, people paint this story in all kinds of dire language.

There's also the story of the Swiss scientist who published a paper warning of all kinds of potential, but mostly not yet measurable, dangers associated with microwaved foods. A Swiss trade association effectively barred him from publishing any more papers because he "interfered with commerce." This decision was later reversed and the doctor was given compensation. This story is told largely as a sign that the little guy, fighting against the big industry machine, was oppressed and that therefore his assertions must be correct. But nowhere does anyone citing the Swiss doctor's paper say that anyone else found data that corroborated what he said initially.

People keep telling these same stories, over and over. They also say things like, "Your mother was right to be suspicious of microwaves." They say microwaves produce radiation -- using "radiation" as a scary word, when all things with energy produce radiation, including us people.

I am not a scientist, and I don't have the means to conduct the kinds of experiments I would want to conduct to answer this question for myself definitively. I also don't have access to costly chemistry research papers that might answer my question. What I do have access to -- the public Internet -- is giving me some indications that lead me to my conclusion.

I am not impressed by the doom-sayers' techniques of citing the same anecdotes, referring to individual events that took place over a decade ago. I've seen other people use this tactic, about other topics, and it usually turns out that they're either 1) spreading gossip, 2) grossly underinformed about the facts or the science or the details behind the event, or 3) fear-mongering. I'm not accusing any of the sources I've cited of taking part in this kind of activity; I'm only saying their evidence looks a whole lot like the partial and uninformed evidence I've seen elsewhere in other circumstances.

So my take is this: I'm not going to fear my microwave, or throw it out, or try to convince others to do likewise. I'm probably not going to cook too many vegetables in it, however, but I don't really do that anyway. I mainly use it to heat up soup or some frozen doo-dad, which is not exactly high on the nutrition pyramid anyway. I already don't use it to cook all-out meals, and I don't plan to start doing so.

The upshot: I'm not going to change much about the way I use my microwave. But I sure did learn a heck of a lot about how it works.

"Radiation Ovens: The Proven Dangers of Microwaves," reprinted all over the place, available here through Lawgiver.Org
Chemguide, "Structural Isomerism" classroom guide
Kirk-Othmer Encyclopedia of Chemical Technology, "Coordination Compounds," (section 1.2.1) by Katharina M. Fromm, February 14, 2003

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