Ignore those alarmist reports, your microwave oven is safe

Misinformation on food and health is being peddled to unsuspecting consumers by local media. This is scary as it is hampering the war against chronic and lifestyle diseases.

The trend is quite worrying, taking into account that majority of Kenyans literally consume anything written in print media or appearing on the TV screen as the gospel truth.

Recent reports claim that microwave oven causes cancer, and that the high cases of cancer in Kenya could be associated with the use of microwave ovens to warm food. Really?

On January 17, 2011, I published an article in this newspaper titled ‘How safe is the microwave oven’? (You can read the article online on this link: http://www.nation.co.ke/Features/DN2/How%20safe%20is%20the%20microwave%20oven/-/957860/1091176/-/g2u2lqz/-/index.html).

In that article, I described how a microwave oven works and answered questions that users struggle with. In summary, the microwave oven is safe, provided proper procedures are followed during its use.

These include using ‘microwaveable’ appliances to warm food and discarding any broken microwave oven without attempting to fix. This is because during the repair process, it might be poorly fixed, leading to leakage of microwaves which are risky to health.

I still stand by the statement that the microwave oven is safe and does not cause cancer. There is no new information to change that.

I base my argument on the fact that I carried out research for my Doctorate degree on microwave processing of foods between the year 2005 and 2009. From my research work, I published over seven publications in international scientific journals.

In the course of my PhD work, I interacted with top brains from all over the world in the discipline of microwave processing of foods.

I have also attended several international conferences on microwave technology in different countries, including Italy, Poland, Ireland and the latest on June 2012 in Las Vegas, USA, where I scooped the third best poster presentation.

I have researched widely in the area of microwave processing of food. Therefore, to some degree, I can comment on the safety of microwave oven with some authority.

A microwave oven heats food by rotating water molecules at a rate of 2,450 million times per second. Such high rotation leads to water molecules hitting and rubbing against each other, leading to friction, which generates heat.

The generated heat is transferred by the usual three modes, which are either, conduction, convection and radiation. In solid foods, heat is transferred by conduction while in liquid foods, by convection.

Here’s my attempt at repairing the damage:

1. Claim: The microwave oven was discovered and manufactured during Second World War by Germans for quick warming of foods.

Fact: It is true that Germans used microwave radars during the Second World War, but not the microwave oven.

The oven as we know it today was discovered by an American by the name Percy LeBaron Spencer, and the first of it was not manufactured until 1947. The domestic microwave oven was introduced in 1967.

2. Claim: The microwave causes cancer, based on the fact that during the Second World War, when the microwave radar was used by German soldiers to warm themselves by gathering around it, it led to an increase in cancer cases within the force.

Fact: Microwaves are, indeed, dangerous when they come into contact with the human body — or any living organism, for that matter.

There is a well-publicised urban legend where a wet cat died after being dried in a microwave oven. The story goes that the owner was paid a fortune since the manufacturers never indicated that it is dangerous to dry a cat in a microwave.

When microwaves come into contact with the human body, they can have different negative effects on health, ranging from heating up organs to causing their malfunctioning.

This is why microwave ovens have safety mechanisms for automatic switching off when the door is open. This reduces any chances of the user coming into contact with the waves.

It was in the 1930s when German soldiers used radars to warm themselves, and the microwave technology then was in its infancy stages.

It is over 80 years since then, and the technology has been improved tremendously, with different aspects of safety mechanisms now in place. All aspects of the microwave oven that can lead to any health issues have been well taken care of.

But if you sit inside the microwave oven and cook yourself, you will definitely face the deserving consequences, the same as sitting on charcoal, a hot plate, open fire or gas hob.

3. Claim: In 1989, two scientists from Switzerland carried out studies on dangers of the microwave oven and returned alarming results.

Fact: I have tried to search for this work from all scientific reference databases accessible to me without any success.

I have been to Switzerland and they use microwave ovens there. If it is true that those scientists really found incriminating evidence against the microwave, I believe Switzerland would be the first country to ban its use.

4. Claim: Food heated by microwaves causes pathogenic changes in the blood of individuals who consume it, similar to what is seen in the initial stages of cancer.

Fact: This is totally misleading. As you read this, 99 per cent of homes in the US and western Europe use microwave ovens.

They base their confidence on the fact that these ovens have been approved by the World Health Organisation, the Food and Agricultural Organisation, the European Food Safety Authority, and other respected organisations.

These bodies use very strict measures to test consumer appliances and cannot allow use of dangerous equipment.

Microwaves have a low frequency compared to nuclear ionising radiation and are never embedded in the food. It is like saying that after cooking food with a gas cooker, or an electric oven, the cooking gas or electrons are left in the food!

Microwave ovens work the same way an electric switch works; after switching off, the light disappears and the room is engulfed in darkness. Similarly, after switching off the oven, the heating stops and the waves are not left in the food.

5. Claim: Microwaves change the nutrients in food and convert them into cancer-causing agents. The increase in colon cancer in America is thus due to microwaved food, and microwave warming of food affects brain and male reproductive hormones.

Fact: What is the effect on food overheated on a gas cooker, hot plate or jiko? Any food heated to extreme temperatures, whether in a microwave oven, over a hot plate, a gas hob, open fire or on a jiko experiences changes from their natural form.

Such changes can affect health. For example, we know compounds called acrylamides are formed when foods containing carbohydrates and an amino acid — asparagine — are heated to extreme temperatures. Acrylamide is carcinogenic and is present in high levels in chips because potatoes have a high content of asparagine.

Nyama choma is a darling for many. But during the barbecuing process, if the meat is over-heated or charred, it is possible to form carcinogenic compounds called heterocyclic amines which are formed as a result of the reaction between creatine and amino acids.

Another form of carcinogenic compounds that can be found in food as a result of bad cooking are polycyclic aromatic hydrocarbons. These compounds come from man-made sources of heat such as automobile exhaust, trash burning, fumes from cooking fires or cooking oil.

It is therefore misleading to pick one method of cooking and casually — and misleadingly — castigate it without comparing with alternatives.

I am a member of the International Microwave Power Institute, and such claims have been around for quite some time now but there is no scientific evidence to back them.

6. Claim: The microwave oven kills 97 per cent of nutrients in vegetables particularly broccoli.

Fact: This claim is widely quoted, but what is never mentioned is that the broccoli used for the study was cooked in large amounts of water.

Normally, vegetables lose a lot of nutrients if prepared in large volumes of water, at high temperatures and for long periods of time.

Cooking of vegetables in a microwave oven is therefore preferred as it leads to low loss of nutrients because the oven uses very little water and heats very fast.

— Dr Arimi is senior lecturer in Food Science at KeMU, Meru. These are his personal opinions and in no way represent the views of KeMU. (www.arimifoods.com)