Does zapping your vegetables in the microwaves make them less valuable nutritionally? Convenience has become a dirty word when it comes to food, and with good reason given the numerous pitfalls of processed ingredients and fatty fast food. But is utilizing the microwave a worthwhile tool in eating healthy on the go, or is it another modern convenience that strips a well-meaning meal of its benefits?
“Understanding how microwaves work can help clarify the answer to this common question,” the Harvard Medical School Family Health Guide begins. “Microwave ovens cook food with waves of oscillating electromagnetic energy that are similar to radio waves but move back and forth at a much faster rate. These quicker waves are remarkably selective, primarily affecting molecules that are electrically asymmetrical — one end positively charged and the other negatively so. Chemists refer to that as a polarity. Water is a polar molecule, so when a microwave oven cooks or heats up food, it does so mainly by energizing — which is to say, heating up — water molecules, and the water energizes its molecular neighbors.”
The bad news is, some nutrients are lost when veggies are exposed to heat. But the Harvard article notes that that happens “whether it is from a microwave or a regular oven,” and because heat itself is the culprit not the type of heat “cooking with a microwave probably does a better job of preserving the nutrient content of foods because the cooking times are shorter.”
Evidence seems to point to boiling as the least beneficial cooking method whether on the stovetop or in the microwave, “For example, boiled broccoli loses glucosinolate, the sulfur-containing compound that may give the vegetable its cancer-fighting properties as well as the taste that many find distinctive and some, disgusting.” Though the water doesn’t eliminate nutrients it actually leaches them, taking on the vegetable’s properties, and could be made into a healthy stock.
But the researchers note the nutrition can be fickle and what applies to one veg may not be true of another. Variables like density of the food may play a role in their reaction to different cooking methods. In a 2008 study, Itlaian researchers found that boiling carrots actually increased their carotenoid content, while steaming and frying reduced it, “One possible explanation is that it takes longer for vegetables to get tender when they’re steamed, so the extra cooking time results in more degradation of some nutrients and longer exposure to oxygen and light.”
Snopes also debunks the theory, testing out an old email that used to circulate, showcasing a child’s science experiment where microwaved water wilted a poor hopeless plant. Have you previously been careful not to microwave fresh foods, or use the microwave as little as possible? Will you incorporate it as a time-saving cooking method more often, now? — Casandra Armour