Thursday, April 18, 2013


I’ve always been dubious about using a microwave oven for heating food or drink.  We bought a really nice microwave when we did up our kitchen seven years ago.  There it sat on its special shelf…I just couldn’t make myself use it to feed our family.  So in the end we sold it, almost brand new, on Trade Me to someone who was very happy to buy it.

People often ask me about microwave ovens and I usually respond in the negative.  If they were to ask me why, which they usually don’t (sigh of relief), I really didn’t have a convincing answer.  Actually most people don’t understand how microwave ovens work anyway and have heard vague suggestions about microwaves not being very good for you – that’s why we say with some cynicism… “I’m just going to nuke my coffee,” or whatever.   I’ve had enough of my confusion over this issue and I want an answer.  “Are microwave ovens a source of danger or are they safe?

Are my concerns based in the fear of a cancer scare I had in the late eighties?  At that stage I examined my lifestyle, my spirituality, my stress levels, and my nutrition. I assumed a “no microwave oven” approach that I adopted from numerous informative books I read about health and healing.  I never really discovered the ‘why” behind my choice – was it knowledge, or was I depending on hearsay to make my choice?

I’ve tried to summarise my findings, but there is so much information available so I present you with a thirty minute read.  Here is what I am discovering from my lengthy investigation into the subject.
  1. What are microwaves? Microwaves are wavelengths within the electromagnetic spectrum. The closest source of naturally occurring microwaves is our sun, though the specific wavelengths of microwaves that are emitted by our sun are mainly absorbed by our atmosphere. Man-made microwaves are generated by various types of transmitters.
  2. What technology uses microwaves?  There is a huge amount of technological advance made possible by the use of microwaves and its use is increasing all the time.  Microwave technology that’s visible to us in our daily lives include:  cell phones, cordless phones, baby monitors, “Smart Meters,” satellite transmission for TV etc, police speed cameras, medical beepers,  wireless laptops, surgical procedures using microwaves  for very precise heating/burning  of cancer tumours1, advanced radar techniques...and more  
  3. How do microwave ovens work?  Man-made microwaves are created using a transmitter of sorts.  In a microwave oven the waves are created in the “magnetron.”  These waves are oscillating extremely fast and cause the molecules in the food to vibrate at about 5 billion times/second, thus causing friction between the individual molecules.  This friction heats the food2.

As far as I can see from the thirty something hours I’ve spent investigating this topic there seem to be two adversarial groups generating information about the safety of microwave ovens.  Their views seem to be diametrically opposed.  For the purpose of this article, Group One I’m calling “THEY” and Group Two I’m calling “NOT THEY.”

Group One - “THEY,” first became visible between 1954 and 1966 when the US Military saw a need to establish a standard maximum safe exposure limit for microwave radiation used for defence radar applications during the post WW2 period and the “Cold War.”  This was accelerated because of ill effects reported by radar operators that included internal bleeding, leukaemia, cataracts, headaches, heart conditions and jaundice
3.  Almost immediately research was begun to set a proposed standard for maximum exposure to microwave radiation.  Rats were subjected to microwaves at intensities of 6 -10mW/cm2.  No blood abnormalities were reported.  There were moderate apparently reversible changes in the circulation of male hormone reported at 300mW/cm2.4 In a controlled search for eye damage, medical researcher Milton Zaret reported increases in early opacification - in other words the beginning of cataracts in the eyes.5 His work was never proved or disproved, but it was enough to sound an alarm about the danger of over-exposure to microwaves.  Zaret was the first medical doctor to testify in Congress on the hazards of microwaves. On March 9, 1973, he told a hearing convened by then Senator John Tunney, of California:
"There is a clear, present and ever-increasing danger to the entire population of our country from exposure to the entire non-ionizing portion of the electromagnetic spectrum. The dangers cannot be overstated because most non-ionizing radiation injuries occur covertly, usually do not become manifest until after latent periods of years, and when they do become manifest, the effects are seldom recognized." (Non-ionizing radiation means radiation that doesn’t carry enough energy to remove electrons from atoms – as opposed to nuclear radiation which is ionizing).

Eventually in 1966, the US safety standard was set at a maximum safe exposure of “10mW of microwave radiation per square centimetre of area.”  (The current NZ/ Aust. safety standard is half that at 5mW/cm2).  There were other examples of research carried out during this time that will make this article far too long. If you’re interested Google “Origins of U.S Safety Standards for Microwave Radiation.”6 
“THEY,” originally included decision makers who were not primarily focussed on public health, but on military applications for defence.  “THEY’ also included military contractors, medical research companies using microwave technology and commercial companies beginning to produce microwave ovens – the public at this stage were not involved.  The safety standard was set amidst the “Cold War” and conflicting interests.  In the final rush it’s possible that some research didn’t get funded that might have cleared up certain questions7 that weren’t only based on the frictional heating effects caused by microwaves. These questions might include the effect on the thyroid gland, influence on cell growth, on blood constituents, on hormones in the brain…

Group Two, “NOT THEY” seems to be made up of the general public (professional and non-professional) who are aware of alternative health and criticism of the early research done in the 50’s and 60’s.  One of the frequently quoted experiments I found on health websites was carried out in 1989 by a Swiss food scientist, Dr. Hans Hertel. 
Dr Hertel, who was genuinely concerned because of his knowledge of the denaturing of food that is carried out by companies producing food for shelf life, set out to study the effects of microwaved nutrients on the blood and physiology of human beings.  He was refused funding for his work, but carried out a small, well-controlled study of nine individuals, including himself.  Please check this site for a well written account of his work.  The results of this study (and I summarise) showed that microwave cooking altered nutrients in the food which resulted in a measurable effect on the blood of the participants. 1. The haemoglobin levels decreased significantly after taking in microwaved food.  2. The hemocrit increased (hematocrit is a blood test that measures the percentage of the volume of whole blood that is made up of red blood cells).  3. The number of leucocytes (white blood cells) showed a temporary decrease.  These results indicated an early pathological process, as you would find in the beginning of a cancerous process.8

On the publishing of his work Dr. Hertel was taken to court by the Swiss Dealers for Electrapparatuses for Households and Industry for stating that microwaved food causes blood abnormalities.  He was ordered not to publish or speak further about this study. Eventually he made an appeal to the European Court for Human Rights and won the appeal for freedom of speech. The order was partially removed by the Swiss government in 1998.
Other repeatedly quoted reports on most of the health websites include: 

  • William Kopp mentions that from 1957 to 1999, researchers experimenting with microwaves at the Institute of Radio Technology at Klinsk in Byelorussia found that prepared meats, cereal grains, root vegetables and milk heated in a microwave oven created cancer-causing agents in these foods. Ingestion of these foods caused a higher percentage of cancerous cells in the blood.  These findings caused microwave ovens to be banned in Russia in 1976,9 they were apparently reinstated in 1987 as a result of international pressure on free trade.
  • 1991, an Oklahoma lawsuit: Mrs N. Levitt had hip surgery and did not recover from surgery due to the blood transfusion she received.  The blood had been warmed in the microwave oven and the transfusion was the cause of death.10
  • In the journal Paediatrics (vol 89, no.4, April 1992), there was an article entitled, “Effects of Microwave Radiation on Anti-infective Factors in Human Milk.”11 It was reported that microwaved breast milk showed degradation of antibodies which may have been caused by ‘hot spots’ created by uneven heating which is characteristic of microwave heating.

Opponents, “THEY”, often state that the Hertel study is not valid as it hadn’t been properly set up to eliminate variables.  However, I wonder why funding cannot be found to carry out some food related research that will settle these questions. Perhaps it’s because microwave ovens are just the smallest tip of the whole microwave technology iceberg.

With regard to the New Zealand situation, the National Radiation Laboratory has been measuring microwave leakage from a wide range of new and used ovens for several years.  In the most recent survey 228 ovens were checked and any leakage was well below the maximum permitted level.12  When I read this I realised that it is expected that microwave ovens must leak otherwise there would be no need for the safety standard to be applied to them.

NZ and Australian “safety standards” for devices that emit microwave radiation are based on the assumption that microwave radiation is harmless unless it is sufficiently strong to heat body tissues. The Australian/New Zealand Standard for microwave ovens states “The microwave leakage at any point 50 millimetres or more from the external surface of the appliance shall not exceed 50 watts per square metre' (which is the same as 0.5mW/cm2).  Exposure to sufficiently high levels of microwaves will cause heating. In the case of human tissue, excessive heating could have serious health effects such as deep tissue burns and hyperthermia. The purpose of Australian Standards is to avoid all known adverse health effects by limiting exposures to levels below those at which heating occurs.”13

In conclusion:  There are still uncertainties about how microwaves affect living organisms that have not yet been addressed.  There seems to be a ‘suspicion of conspiracy’ that is driving the “NOT THEY” group based on the questions raised by Dr. Hans Hertel’s study.  This increasing suspicion is set to remain unless there is a better flow of information between research organisations and the general public.  People in the “NOT THEY” group believe that information from technological research has been held back from them and this can resulted in biased reporting and the creation of public anxiety.14

Now that I’ve read a range of articles, scientific research papers, skim read the Hertel court case and considered many opinions, my response is that if there is even the tiniest wisp of smoke there must be fire somewhere.

It appears that microwave ovens are relatively harmless operated at the safety levels for exposure that we have in place.  Like so many things moderation is the key.  From my reading I have been alerted to the increasing exposure to electromagnetic fields that is progressively being experienced into our own homes.  I’m talking about wireless, cell phones, Smart Meters and so on.  Let’s not bury our heads in the sand as we need to look into these things for ourselves and not be carried away by fear or ignorance.

Oh, by the way, I’ve decided that I won’t be buying another microwave oven, and if I already owned one I would only use it on low power if I had to defrost something occasionally.  I wouldn’t cook food in it.  I might use it to sterilise the dish cloth every night.  If I used it I would stand about a metre away from it when it was working.  When it came to the end of its life I wouldn’t replace it, I’d buy our family another appliance that I’d use even more, such as a flour mill, or a high power blender or a decent auger juicer, or maybe a gas hob.11

Thanks to all of you who responded to my question about whether you’d use a microwave oven to warm baby formula (if you couldn’t breastfeed) or baby food.  About 90% of those who replied said that they wouldn’t use a microwave to heat a baby’s food.  Your replies helped me and caused me to look in various directions for information.

Yours, trying to be wise and not fanatical,


3. J.R.McLaughlin, A Survey of Possible Health Hazards from Exposure to Microwave Radiation (Hughes Aircraft Corporation, Culver City, California, 1953)
4. Proceedings of the Fourth Tri-Science Conference On the Biological Hazards of Microwave Radiation (Plenum, New York, 1961) From summaries in the Origins of U.S. Safety Standards for Microwave Radiation(Science, Vol 208, June 1980)
5 M.Zaret in Proceedings of the Third Tri-Science Conference On the Biological Hazards of Microwave Radiation (University of California, 1959)
6 N.H.Steneck, H.J. Cook, A.J.Vander, G.L.Kane Origins of U.S.Safety Standards for Microwave Radiation (Science, Vol 208, June 1980)
7 N.H.Steneck, H.J. Cook, A.J.Vander, G.L.Kane in (6)
8 Dr Hans U. Hertel Journal of Natural Science, Vol 2, No 4, 1999 (Bern, Switzerland)
9 William Kopp,  Journal of Natural Science, Vol 1,, 1998
14 N.H.Steneck, H.J. Cook, A.J.Vander, G.L.Kane in (6)

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