Are Microwave Ovens Really Safe?

"To 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.

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Mark Sisson

Mark Sisson is the author of several books, including Maximum Results, The Fat Control System, The Anti-aging Report and The Lean Lifestyle Program (over 400,000 copies distributed). He edited the Optimum Health national health newsletter from 1994 through 1996.

He is the founder of Primal Nutrition and the author of Mark's Daily Apple.

Mark Sisson

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Comments

  1. Anonymous says

    I read about a study done in either 1978 or 1987 showed that microwaving foods with amino acids changed them to something toxic. I know meat and eggs have amino acids but wasn’t sure what other foods did, so I stopped using the microwave. Good to know I can heat water and cook fruits and vegetables.

  2. Glenn O'Dell says

    I’ve observed one scary phenomenon in the microwave: Cooking dry broccoli florets produces visible arcing among the florets. The result is scorched & carbonized bits in the florets- not healthy. I always immerse them in water to microwave.

  3. Anonymous says

    I read that after World War II Russians got results of German’s experiments on prisoners with microwaves.
    As a result, Microwave ovens were prohibited in Soviet Union.

  4. Anonymous says

    Dont believe everything you read, its a hoax that the Russians banned microwaves and alot of mis-information exists. As always use good judgment and common sense. Steaming veggies is the best and healthiest way to cook them, steam baskets are cheap and it encourages families to eat more veggies. Microwaves are good for the occasional quick cook job as needed but Im all for using the healthiest method possible.

  5. Seg says

    About the only “good use” for a microwave is to zap your sponges – nuking for 2 minutes will kill all the bacteria and viruses.

    One can also use vinegar and hydrogen peroxide to do the same thing, so in reality there is absolutley NO GOOD DARN USE FOR A NUKER !!!!

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