The first time I became skeptical of microwave ovens was when I conducted a small experiment by myself comparing the growth of plants (from seedlings) watered with regular distilled water vs. water that had been microwaved. Much to my surprise those plants that had been watered with microwaved water did not grow, or grew very poorly. Those watered with distilled water flourished, just as the rest of the plants in my house normally had. This experiment has not only been confirmed by myself, but many others as well (a simple google search will bring up numerous reports of microwaved water being quite un-suiting to grow plants with).
So what happens to the water when it is microwaved? If such an effect occurs with plants, then why are we consuming foods that are microwaved? Can our bodies even utilize the nutrients in foods that have been microwaved?
A microwave oven creates radio waves at frequencies of around 2.45 GHz. As with other wave types, a radio wave is a type of electromagnetic radiation. When matter is heated in the microwave the atoms and molecules vibrate quickly to generate kinetic energy (or heat), such as they would on the stove or in the oven. The only difference here is that microwaves have very strong electric fields. Electric fields have the ability to stretch molecules, as well as separate their charges so that the atoms lose an electron (ionization).
Electric fields in microwave ovens cause electric current to flow into food, which then has the ability to rearrange the atoms in your food, changing the molecular structure (ionization). This is one of the reasons why microwave ovens have the capability to destroy essential nutrients in your food as compared to cooking on the stove. Ionizing (displacing single electrons) is what has the ability to form free radicals in your food. Free radicals are harmful to our body and one of the major culprits in cancer formation.
Microwaved meats cause the formation of d-Nitrosodienthanolamines (1), a well-known carcinogen, as well as turning plant alkaloids from microwaved vegetables into carcinogenic matter that should not be consumed by humans (or any animal for that matter). In addition, microwaves lower nutrient content of foods by as much as 60 to 90% – in a study by Russian researchers, they found that there was marked decrease in the bio-availability of vitamin B complex, vitamin C, vitamin E, essential minerals and lipotropic factors in microwaved foods. Another study published in November 2003 found that microwaved broccoli in a little bit of water lost up to 97% of its beneficial antioxidants compared to steamed broccoli (stove-top) which lost only 11% antioxidants (2).
In 1992, Richard Quan and colleagues took freshly frozen human milk samples and microwaved them for over 30 seconds at different temperatures. They found that the milk heated at high temperatures (98ºC) had lost nearly all of it’s resistance to contamination, and when exposed to E.coli, became infected 18 times faster than unheated breast milk. Even milk heated at low temperatures (25ºC) had a chance at becoming infected five times faster by E.coli than unheated breast milk (3).
In 1989, Dr. Hans-Ulrich Hertel, a Swiss food scientist conducted a study to examine and research the effects of microwaved food on humans. He recruited nine people, including himself, and alternately exposed them to microwaved and conventionally cooked food from organic sources. Before consuming these foods, a sample of blood was drawn, as well as at certain intervals after eating.
They found that after microwaved food consumption there was a dramatic reduction of all blood hemoglobin and cholesterol values (both good (HDL) and bad (LDL)), and that LDL cholesterol levels were slightly more elevated relative to HDL cholesterol levels. In addition, lymphocyte (white blood cell) activity was considerably reduced after ingesting microwaved foods, compared to foods that had been conventionally cooked. When the blood of those who consumed microwaved foods was exposed to bacteria, the bacteria flourished, whereas blood from those who did not consume microwaved foods had much lower bacterial count. This suggests that the energy from microwaved foods has the ability to be passed onto those who consume the food (4).
(1) Lee, L. “Health effects of microwave radiation – microwave ovens.”
(2) Vallejo, F., Tomas-Barberan, F. A., & Garcia-Viguera, C. “Phenolic compound contents in edible parts of broccoli inflorescences after domestic cooking.”
(3) Quan, R., Yang, C., Rubinstein, S., Lewiston, N., Sunshine, P., Stevenson, D., & Kerner, J. (1992) Effets of microwave radiation on anti-infective factors in human milk. Pediatrics, 89, 667-669.
(4) Wayne, A., & Newell, L. “The hidden hazards of microwave cooking.”