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You may have heard claims that nuking your cold leftovers in the microwave is not such a good idea because it destroys their nutritional value. Is that true? Well, we’re gonna have to get a little scientific to find out. Come along, class!

Two scary words, “radiation” and “radioactive”, often come up when talking about microwaves. Many assume they mean the same thing, but they don’t. There is an important distinction between them. Radiation is simply a broad term for the release of energy in the form of waves. Radioactivity is one particular means, among many, to generate radiation.

Hold tight, we gotta go a little deeper. There are two types of radiation waves: high frequency and low frequency.

High frequency waves alter molecular structures they have contact with. That’s significant. Ultra-violet and x-rays fall into this category, and sunscreen and lead vests attest to their harmful effects. The ultimate destructive waves are generated when the nucleus of an atom is deliberately split – this is called radioactivity. But, fear not, unless your soufflé explodes, you’ll never see a mushroom cloud in your microwave.

That’s because microwave ovens use harmless low frequency waves which do not affect the structure of molecules they contact. All around us, towers are generating low energy waves to run your cell phone, television, and Wi-Fi. And in the oven, the only effect of microwaves is the vibration of water molecules in food. Just as rubbing your hands together generates heat, the friction of water molecules warms the food. It’s that simple.

You may not have known that heat from any source will destroy nutrients in food. In fact, the higher the heat and the longer that high heat is applied, the more destruction occurs. Tests show that frying food can cause the most loss of vitamin and mineral potency. Boiling causes many nutrients to leach into the water instead of being consumed. Even long broiling times reduce nutritional value.

Depending on the food, many nutritionists agree that conventional and microwave ovens are the best choices. Low-and-slow in an oven will deter nutrient loss, allow time for flavors to blend, and brown foods when necessary. The moderate temperatures of a microwave, for a very short amount of time, are especially perfect for heating prepared foods or steaming vegetables.

Perhaps a bigger concern than good nutrients leaching out of food; is bad chemicals leaching in from plastic containers. Most, but not all, companies have banned dangerous, even carcinogenic, chemicals from their packaging. However, some plastic dishware still has toxins like BPA, dioxins, and benzene which have been proven to infiltrate the food they have contact with. This is why only glass or ceramic containers should be used in any microwave cooking.

Still, there are other issues to consider when microwaving. Heating is generally uneven and some complain of the food texture being lost. You can’t brown and crisp food in the microwave, either. But these are matters of preference. As far as fearing that my food is worthless, or worse, somehow radioactive; well, I’ll get back to you on that after I zap my leftover pizza.