Microwave ovens have been the norm in US households for almost 50 years. If you’re under 40, you’re more likely to have grown up with a microwave than without. Ever since they were first introduced, microwaves have been a source of controversy. While manufacturers and retailers maintain that microwaves are completely safe, many people still want to know: are microwaves dangerous?
Many of the original concerns about microwave safety, such as radiation leaks and pacemaker problems, have been addressed by modern technology. However, there remain real, potentially serious, health issues that arise from microwave use. Leaks, burns, nutritional concerns, and promoting a culture of laziness and immediate gratification are all good reasons why you may want to consider a different cooking method.
I personally don’t use a microwave. I don’t have one in my house, and we don’t have one in the breakroom at Global Healing Center. First, I’m not a fan of what they produce—food that’s frozen on the inside, and lava-hot on the outside, not to mention bland and soggy. More importantly, I do not believe that microwaves are the safest, or most nutritious, method of cooking food.
Radiation and How Microwaves Work
Ozeri ZP3-20 8” ... Best Price: $12.00 Buy New $21.31 (as of 04:15 EST - Details) Let’s talk about radiation. Since microwaves were first available, the biggest concern people have had is the danger of keeping a household appliance designed specifically to create radiation. Microwaves cook food using microwave radiation, generated by a device called a magnetron. Microwave radiation is non-ionizing. Non-ionizing radiation is relatively low energy and is not hazardous when confined to a microwave, especially compared to high-energy ionizing radiation. However, even with a relatively low output, microwave radiation can still cause burns. If you’ve ever cooked meat in a microwave, you’ve seen what unshielded non-ionizing radiation can do to flesh.
Microwaves are shielded specifically to prevent most leaks. However, the key word is “most.” Even at peak efficiency, domestic microwaves do leak some heat. The US Food and Drug Administration allows for some leakage as long as radiation levels fall below what they consider harmful to humans.  Microwaves are regulated to ensure only low levels of radiation escape—most of which dissipates within one or two feet.
That may sound good, but low radiation is different from no radiation. The effects of long-term, low-dose, non-ionizing radiation are difficult to observe, and we don’t yet know the full consequences for the human body.
A 2004 study found that small doses of ionizing radiation over the course of years may increase the risk of leukemia. However, this doesn’t tell us much about microwaves. That study focused on the effects of ionizing radiation—specifically the type found in medical scanners. As microwaves produce non-ionizing, electromagnetic radiation, the study isn’t applicable. As of this writing, no long-term studies on the effects of microwave radiation on humans have been completed.
Furthermore, the risk is only minimal if you use a well-maintained appliance according to manufacturer’s exact instructions. That risk grows considerably if the door, hinges, latch, enclosure, power supply, or seals are damaged. If the shielding is compromised, radiation can leak out. Units with damaged seals, which is especially common in older units, can present a hazard. If your microwave shows signs of damage, send it to the recycling center. Even with an undamaged microwave, dirty door seals can create gaps that allow radiation to escape. Check your seals after every use.
An old concern about microwaves was that the waves they use to cook food could disrupt the function of pacemakers. That’s why microwaves used to have pacemaker warnings on them. Both pacemakers and microwaves these days are shielded well enough to avoid these complications. However, if you have a pacemaker, you should still exercise caution around microwaves. If you feel dizziness or discomfort, get away from the machine immediately and consult your healthcare provider. The Spice Lab Himalaya... Best Price: null Buy New $7.49 ($0.23 / Ounce) (as of 02:20 EST - Details)
Microwave Burns and Superheated Water
Even a brand new microwave carries a small risk of causing burns. Microwaves heat unevenly, and larger portions of foods may not cook all the way through. A food item that seems cool to the touch might scald your mouth when you bite into it.
A lesser-known danger of microwaves is the phenomena of superheated water. When water is heated in a perfectly smooth container, it can actually be heated past the boiling point without actually boiling. Once water is superheated, any slight disturbance, such as picking up the cup, can cause the water to boil all at once, resulting in a violent eruption of scalding water.  Impurities make it easier for water to boil, so pure, clean water, like distilled water, is far more likely to experience superheating.
To avoid superheating, never heat water in a microwave for excessive periods of time. Be especially careful with distilled water. A simple way to prevent superheating is to leave a nonmetallic object, like a wooden stir spoon, in the water while you heat it.
How Microwaves Affect Food Quality
While I remain concerned about the burn risks of microwaves, the real health concerns lay in how they affect nutrition.
Microwaves do alter the nutritional content of food; this fact is not in debate. (This is one reason why I advocate for a mostly raw, vegan diet.) The real question is if microwaving food alters its nutritional content differently than other forms of cooking. All cooking changes the chemical structure of food to some degree, but different types of heating alter nutritional content in different ways. For example, broccoli loses about 74 to 97 percent of its Effortless Healing: 9 ... Best Price: $5.30 Buy New $11.01 (as of 11:39 EST - Details) antioxidants when boiled, but retains its nutrients when steamed.
So what nutrients are specifically affected by microwaving? Alliinase, found in garlic, is one. Alliinase is an enzyme with significant benefits for the immune and cardiovascular systems. Unfortunately, it’s sensitive to heat. Forty-five minutes in an oven will render alliinase inert. That’s bad, but there’s a lot you can cook in under 45 minutes. In a microwave, it takes just 60 seconds.
Do you have a breastfeeding infant? Never warm breastmilk in a microwave. Microwaving destroys the essential disease-fighting, baby-protecting agents in breast milk. In one study, breast milk microwaved for just 30 seconds destroyed natural antibodies, paving the way for the growth of potentially harmful bacteria. 
There are more examples of compromised nutrition. An Australian study showed that microwaves cause a higher degree of “protein unfolding” than conventional heating. If you have a choice, you want your proteins properly folded. Protein nutrition depends on its structure—when it unfolds, it becomes just a strand of amino acids. You lose the nutritional functionality of the protein. Microwaves are also capable of extensively fragmenting and destroying bacterial DNA, doing so to a far greater degree than heating alone.