Almost every American home has one. The convenience offered by owning a microwave oven is almost undeniable. But there remains a level of skepticism for many—a lingering feeling that using a microwave to cook food may somehow make food less healthy. Does cooking with a microwave take nutrients out of food?
Understanding how microwaves work can help clarify the answer to this common question. 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.
In addition to being more selective, microwave-oven energy is also more penetrating than heat that emanates from an oven or stovetop. It immediately reaches molecules about an inch or so below the surface. In contrast, regular cooking heat goes through food rather slowly, moving inward from the outside by process of conduction.
Some nutrients do break down when they’re exposed to heat, whether it is from a microwave or a regular oven. Vitamin C is perhaps the clearest example. So, as a general proposition, cooking with a microwave probably does a better job of preserving the nutrient content of foods because the cooking times are shorter.
As far as vegetables go, it’s cooking them in water that robs them of some of their nutritional value because the nutrients leach out into the cooking water. 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. The nutrient-rich water from boiled vegetables can be salvaged and incorporated into sauces or soups.
Is steaming vegetables better? In some respects, yes. For example, steamed broccoli holds on to more glucosinolate than boiled or fried broccoli.
But this is nutrition, and nothing in nutrition is simple. Italian researchers published results in 2008 of an experiment comparing three cooking methods — boiling, steaming, and frying — and the effect they had on the nutritional content of broccoli, carrots, and zucchini. Boiling carrots actually increased their carotenoid content, while steaming and frying reduced it. Carotenoids are compounds like lutein, which may be good for the eyes, and beta carotene. 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.
But let’s not get too lost in the details. Vegetables, pretty much any way you prepare them, are good for you, and most of us don’t eat enough of them. And the microwave oven? A marvel of engineering, a miracle of convenience — and sometimes nutritionally advantageous to boot.
ibaL recommends: Concentrated fruits & vegetables
Though we may not give them much thought unless they’re bothering us, our internal organs are what allow us to go on eating, breathing and walking around. Here are some things to consider the next time you hear your stomach growl.
1. The largest internal organ is the small intestine. Despite being called the smaller of the two intestines, your small intestine is actually four times as long as the average adult is tall. If it weren’t looped back and forth upon itself it wouldn’t fit inside the abdominal cavity.
2. The human heart creates enough pressure to squirt blood 30 feet. No wonder you can feel your heartbeat so easily. Pumping blood through your body quickly and efficiently takes quite a bit of pressure resulting in the strong contractions of the heart and the thick walls of the ventricles which push blood to the body.
3. The acid in your stomach is strong enough to dissolve razorblades. While you certainly shouldn’t test the fortitude of your stomach by eating a razorblade or any other metal object for that matter, the acids that digest the food you eat aren’t to be taken lightly. Hydrochloric acid, the type found in your stomach, is not only good at dissolving the pizza you had for dinner but can also eat through many types of metal.
4. The human body is estimated to have 60,000 miles of blood vessels. To put that in perspective, the distance around the earth is about 25,000 miles, making the distance your blood vessels could travel if laid end to end more than two times around the earth.
5. You get a new stomach lining every three to four days. The mucus-like cells lining the walls of the stomach would soon dissolve due to the strong digestive acids in your stomach if they weren’t constantly replaced. Those with ulcers know how painful it can be when stomach acid takes its toll on the lining of your stomach.
6. The surface area of a human lung is equal to a tennis court. In order to more efficiently oxygenate the blood, the lungs are filled with thousands of branching bronchi and tiny, grape-like alveoli. These are filled with microscopic capillaries which oxygen and carbon dioxide. The large amount of surface area makes it easier for this exchange to take place, and makes sure you stay properly oxygenated at all times.
7. Women’s hearts beat faster than men’s.The main reason for this is simply that on average women tend to be smaller than men and have less mass to pump blood to. But women’s and men’s hearts can actually act quite differently, especially when experiencing trauma like a heart attack, and many treatments that work for men must be adjusted or changed entirely to work for women.
8. Scientists have counted over 500 different liver functions. You may not think much about your liver except after a long night of drinking, but the liver is one of the body’s hardest working, largest and busiest organs. Some of the functions your liver performs are: production of bile, decomposition of red blood cells, plasma protein synthesis, and detoxification.
9. The aorta is nearly the diameter of a garden hose. The average adult heart is about the size of two fists, making the size of the aorta quite impressive. The artery needs to be so large as it is the main supplier of rich, oxygenated blood to the rest of the body.
10. Your left lung is smaller than your right lung to make room for your heart. For most people, if they were asked to draw a picture of what the lungs look like they would draw both looking roughly the same size. While the lungs are fairly similar in size, the human heart, though located fairly centrally, is tilted slightly to the left making it take up more room on that side of the body and crowding out that poor left lung.
11. You could remove a large part of your internal organs and survive. The human body may appear fragile but it’s possible to survive even with the removal of the stomach, the spleen, 75 percent of the liver, 80 percent of the intestines, one kidney, one lung, and virtually every organ from the pelvic and groin area. You might not feel too great, but the missing organs wouldn’t kill you.
12. The adrenal glands change size throughout life. The adrenal glands, lying right above the kidneys, are responsible for releasing stress hormones like cortisol and adrenaline. In the seventh month of a fetus’ development, the glands are roughly the same size as the kidneys. At birth, the glands have shrunk slightly and will continue to do so throughout life. In fact, by the time a person reaches old age, the glands are so small they can hardly be seen.
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