What are the health effects of microwave radiation?
A large amount of literature has been published on the biological effects of microwave radiation. Generally speaking, exposure to very high levels of microwave radiation can result in significant amounts of energy being absorbed by the body. Just as with food, this energy is transformed into heat in the body. Sensitive body parts, such as the eyes, testes and brain, are not able to get rid of the extra heat that may build up. However, the situations where effects of thermal (heat) damage has actually occurred to the eye or brain required long term exposure to very high power densities well in excess of those measured around microwave ovens.
Some biological effects cannot be explained by a temperature rise in the body or in any one part. Persons working in microwave fields have reported headaches, eyestrain, over-all fatigue and disturbance of sleep. These effects have been associated with the interaction of the microwave fields with the central nervous system of the body. Such effects have been labeled as "non-thermal" interactions. These may be responsible for some of the long-term effects from prolonged exposure to low levels of electromagnetic fields. There is no confirmed scientific evidence to prove a link between such effects and microwave radiation exposure. However, it must be emphasized that these effects usually occur with pulsed or pulse-modulated fields and not with the continuous wave fields associated with microwave ovens.
 Unsafe for Heating Baby Bottles and Milk
Microwave ovens are also considered unsafe for heating baby formula and expressed breast milk. Young Families, the Minnesota Extension Service of the University of Minnesota, published the following in 1989:
"Although microwaves heat food quickly, they are not recommended for heating a baby's bottle. The bottle may seem cool to the touch, but the liquid inside may become extremely hot and could burn the baby's mouth and throat.
Also, the buildup of steam in a closed container, such as a baby bottle, could cause it to explode. Heating the bottle in a microwave can cause slight changes in the milk. In infant formulas, there may be a loss of some vitamins.
In expressed breast milk, some protective properties may be destroyed. Warming a bottle by holding it under tap water, or by setting it in a bowl of warm water, then testing it on your wrist before feeding may take a few minutes longer, but it is much safer."
Dr. Lita Lee of Hawaii reported in the December 9, 1989 Lancet:
"Microwaving baby formulas converted certain trans-amino acids into their synthetic cis-isomers. Synthetic isomers, whether cis-amino acids or trans-fatty acids, are not biologically active.
Further, one of the amino acids, L-proline, was converted to its d-isomer, which is known to be neurotoxic (poisonous to the nervous system) and nephrotoxic (poisonous to the kidneys). It's bad enough that many babies are not nursed, but now they are given fake milk (baby formula) made even more toxic via microwaving."
In 1945 engineer Percy Spencer was researching radar at the Raytheon company. He stopped for a minute in front of a magnetron, an electronic vacuum tube that generates high-frequency radio waves. Suddenly feeling a strange sensation, he noticed that the chocolate bar in his pocket was melting.
Intrigued, Spencer placed popcorn kernels near the magnetron; soon popcorn was popping out over the lab floor. Spencer then put a raw egg in a pot in front of the magnetron. The exploding egg splattered a nearby coworker, confirming that microwaves could cook food quickly and unconventionally.