Marks Daily Apple
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18 Mar

Are Microwave Ovens Safe?

79801192 436e54c431To Nuke or Not to Nuke?

The verb itself suggests the unleashing of atomic destruction, but we wondered, “Is there a grain of truth behind the slang?” What’s the real story behind these boxes of convenience sitting in so many of our kitchens? Are microwaves a benign bastion of modern handiness or, as some claim, a sinister contributor to our physiological (at least nutritional) undoing?

It’s likely that we find ourselves in a variety of camps on this issue. Some of us swear them off. Others unapologetically swear by them to get through the normal course of a busy day. And then there are those of us in the dithering middle who routinely stare at each plate of leftovers or bowl of frozen vegetables, sometimes reaching for the pots and pans and other times giving into convenience but always questioning whether we’re paying for it.

Should we be plagued by these pangs of conscience? Are we emitting dangerous radiation into our homes or killing off the nutritional value of our unsuspecting food? Are we making a mountain out of a molehill? What should we believe? Is there enough evidence to really tell either way?

We definitely know this much. Grok didn’t have a microwave. But, then again, he didn’t have a jet shower, Bose stereo system, or Hammacher Schlemmer thumper massager. (Trade-offs, you know…) As much as we love Grok and think his era has been unduly disparaged, we aren’t arguing that he had the best life possible or that anything he didn’t have isn’t worth having. Nonetheless, while it’s a naturalistic fallacy to assume that everything post-Paleo is an abomination, it’s both fair and reasonable to question the safety of today’s customary appliances.

Here’s what we found. First, to the question of transforming your home into a radiation zone… There is, not surprisingly, disagreement about this point. However, occasional home use of a fully functional microwave appliance is generally considered safe. Microwaves do, make no mistake, emit radiation, and the FDA has established what it considers “safe” levels for microwaves: over the machine’s “lifetime” the allowable level is “5 milliwatts of microwave radiation per square centimeter…approximately 2 inches from the oven surface.” Guidelines from the International Radiation Protection Association (IRPA) suggest overall radiation limits of 1 milliwatt per square centimeter “averaged over 6 minutes (0.1 h) period.” Unless you’re using your microwave on a perpetual basis, there’s little reason to worry.) Because the radiation diminishes quickly over distance, standing further away from the microwave during operation cuts your exposure even more significantly. (That instinct to not press your face against the glass door while your lunch was cooking turns out to be right after all…) Additionally, the FDA requires two interlock systems that effectively offer backup security as well as a monitoring system that shuts the microwave down if one of the systems isn’t working or if the door is opened during operation. Common sense adds that you might want to make sure the microwave seal isn’t compromised by built up tomato sauce or other grime. (Hmmm…anyone?) And, of course, it’s a good idea to replace an old, dilapidated microwave even if it’s a great conversation piece. Safety versus vintage flare…

And now for the more common question. What about the nutrients? (We should mention quickly that microwaving of food isn’t the same as food irradiation, which involves a higher level of energy and is considered much more damaging in terms of “complex chemical changes … in food components.”) But how do nutrients fare behind the closed, latched, double interlock system door? Well, it varies. As we’ve reported in the past, cooking of any kind can sometimes reduce the nutritional value of food and occasionally enhance it. Slow and low are typically the way to go with cooking, as we’ve said. A pretty much universal concept for our friends, fruits and veggies: steaming or cooking/microwaving with small bits of water trumps boiling or deep frying. When it comes to microwaving itself, studies suggest some mixed reviews for individual vegetables or nutrients but indicate, overall, that microwaving generally preserves nutrient levels.  One study using Brassica vegetables found that microwaving resulted in comparable nutrient (glucosinolates, a possible cancer preventative compound) loss when compared to steaming or stir frying.  (Actually, shredding the vegetable ahead of time had more impact on nutritional value than the cooking method.) However, another study using broccoli suggests that antioxidants can be significantly depleted.  (Antioxidants, particularly water soluble vitamins, appear to be most at risk while minerals tend to be generally preserved in microwave preparation.) Yet another study review showed that microwaving with low power settings offered “equal or better retention of nutrients … as compared with conventional, reheated foods for thiamin, riboflavin, pyridoxine, folacin, and ascorbic acid.” University of Illinois research also showed that microwave blanching (brief exposure to high heat used for pre-freezing preparation to lengthen storage ability of frozen produce) was as or more successful in retaining nutritional value than conventional blanching methods. (Nonetheless, blanching does diminish nutrient levels.)

But how could microwaving actually preserve more nutrients in many cases? Not only do we generally use less liquid when cooking in the microwave, cooking times are typically shorter than those for conventional cooking. (As a side note, new ceramic cookware designed for microwave use shows promise to cut cook times further still, which can mean even greater nutrient preservation.)

Our best advice: nuke wisely. If the convenience of a microwave keeps you committed to PB eating, use it as you need to. (We’re all for leftovers, freezing fresh produce to save money, etc.) Nonetheless, thinking outside the micro box is likely a good idea as well. Invest in some small pans for single servings or small cooking jobs. (If it takes up less space in the dishwasher/sink, it seems like less of a chore.) And, of course, avoid heating (and especially reheating) whenever you can to retain the most nutrition. Heat only the ingredients you must to make a dish palatable, and keep water use, time and temp (power level) as low as possible. (Bonus: it helps you avoid those nasty steam burns from handling overheated dishes.)

Have your own reasons for yea or nay on nuking? Let us know what you think and any tricks you’ve found useful to avoid or minimize microwaving.

limonada Flickr Photo (CC)

Further Reading:

Should I Stop Eating Flax Seed?

8 Ways to Reduce Your Chemical Load

What’s Wrong with Juicing?

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

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