Monday, November 06, 2006

Microwave quackery

I was recently sent one of those "Great Discoveries That Could Save Your Life" type e-mails, which purported that microwaved food would kill you, and cited an experiment done by a schoolgirl who watered one plant with purified water and another with microwaved water, and showed pictures of the plant watered with microwaved water dying rapidly. Another piece of damning "evidence" quoted in the e-mail was that a patient was given blood heated up in a microwave and died (I presume it was intravenously delivered and not force-fed :p).

So I did a search on the Net, because I like disproving things that stand in the way of my saving two minutes a day, when I could be spending that two minutes looking at vintage My Little Ponies on eBay :)

Snopes has a nice explanation of the "experiment", and also did their own experiment with THREE plants (so obviously their research is better - teehee!) and (un)surprisingly, all three plants survived and there was little discernible difference between them. They also said that the patient probably died because conventional microwaves heat blood up too quickly, resulting in hemolysis (the breakdown of red blood cells). I'm sure the nurse who killed that patient would have eventually killed someone else through gross incompetence, for example, by putting Sprite in their saline drip or something.

The Straight Dope prefers to give a more neutral reply, saying that there is still a lot we don't know about the effects of microwaves on food, but supposedly a 1992 Stanford study found that microwaving breast milk reduces its levels of vitamins and infection-fighting compounds, making it less beneficial to babies. I wasn't able to find more recent studies on this topic, but this at least sounds like a legitimate reason to me, because it's part of a proper study done by a well-respected institution, and not e-mail scare-mongering and science fair projects.

Finally, my own personal deity, Dr Karl, gives a brief review of two articles (well, one article and one letter to the editor) pointing out that none of them appeared in peer-reviewed journals or show firm scientific results. He also sums up what we DO know about microwaved food.

We do know that water-soluble vitamins (such as C and the B-group) are susceptible to both heat, and to dissolving in the water. These vitamins are retained in microwaved vegetables as well as if they had been steamed, and much better than if they had been boiled.

We also know that microwaved vitamins that are insoluble in water (such as A and D) are exposed to less heat for a shorter time, and so, survive better than if boiled.

Minerals (such as sodium, potassium, etc) are mostly soluble in water, and so are better off being microwaved. Fats and carbohydrates are basically unaffected by regular heating and microwaving. Proteins suffer less oxidation in a microwave oven than in conventional cooking (lower temperatures, shorter time), and so the quality of protein is higher. Indeed, the lack of browning is proof that the heating is gentler.

But one thing you can be sure of - that delicious slightly burnt crispyness that you get with barbequed meat definitely contains chemicals that can (in studies involving lots of rats) cause cancer. Even so, most of us ignore this scientific finding and eat barbequed meat with no ill effects.

So heat, eat and be merry…

A lot of people say they prefer not to cook with the microwave because the food tastes different to them, or they prefer to do things the old school way, and that's fine. Personally, I prefer cooking with gas myself. All I use the microwave for is defrosting and heating up leftovers. To me, it is a fantastic time-saving device if the chicken I put in the fridge to defrost is still a little icy, or if I'd like the fried rice from last night warmed up. But justifying something, anything, with pseudo-science is just irresponsible. These urban legends are propagated and believed by the same gullible people who think that teeth fillings cause cancer and opt to have their teeth pulled out instead, causing much worse health problems for themselves.

That was probably a bad analogy, but it really is one of my bugbears. People have to take responsibility for the crappy state their bodies are in, myself included :D

2 comments:

Anonymous said...

There's nothing like a microwave oven to ruin perfectly good food.

I can't help but wonder if the plants died because the schoolgirl didn't wait for the water to cool before watering with it! (I hope that's not what happened to the patient-- eww.)

Erik

an9ie said...

Hey there Erik, thanks for dropping by!

Yes, microwaved food does seem to lack that certain something. I prefer old-school cooking, but you can't beat the microwave oven for defrosting and reheating.

Re: the experiment, the site at http://www.rense.com/general70/microwaved.htm says the water was cooled first. The fact that Snopes duplicated the experiment and found no difference certainly makes you wonder about the way the experiment was conducted. I would certainly need more solid proof than that to make me give up microwaving!