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To microwave or not?

When it comes to food preparation, we are always looking for ways to simplify and shorten the time spent on cooking, and one of the tools meant to make it more convenient to reheat food quickly is the microwave.

In the United States and other Western countries, the microwave has been a common household item for over 30 years since it was invented after World War II, revolutionising the way food is prepared and cooked.

If you do an Internet search for recipes that use the microwave exclusively to cook a dish, you will find many resources, and this is very convenient for people who live in small, constrained spaces without a proper kitchen. But while the microwave is an easy-to-use tool, what are the consequences that may arise from long-term usage?

How microwaving works

At the end of World War II, microwaves were invented from military radar technology. It is a type of electromagnetic radiation that moves through air in waves. On the spectrum of electromagnetic radiation, microwaves are on the low end of the scale, second to radio waves. Microwaves bounce about the interior of the microwave, causing the water molecules in your food to vibrate millions of times in one second and heating up food quickly.

This is known as dielectric heating. Unlike conventionally cooked foods, items in the microwave are heated from the outside to the inside, and can be uneven if not all parts of the food contain the same amount of water. The uneven heating of food can cause damage to parts of it and microwaved milk can also kill the antibodies and other nutrients found in breast milk. It is also highly inadvisable for mothers to reheat milk bottles to avoid feeding their babies overheated milk.

Additionally, microwaving creates new compounds not found naturally. They are known as radiolytic compounds, but not enough is known about the effects these compounds have on our bodies. Interesting to note is that microwaving is used in gene-altering research to deform and degrade cells, breaking them apart and making them an easy target for microorganisms like viruses and fungi.

If microwaves can do this to food cells, its impact on humans is questionable. However, because the effects of microwaved food on the human body have not yet been fully studied, we aren’t clear of its safety. What can be concluded from the studies that have been done is that microwaving damages the nutritional value of food.

Here are some examples of detrimental effects of microwaves on the nutrients in your food:

• Broccoli microwaved with some water lost up to 97% of its beneficial antioxidants. In contrast, steamed broccoli lost 11% or less of its antioxidants. (From a study published in the November 2003 issue of The Journal of the Science of Food and Agriculture)

A study published in The Journal of the Science of Food and Agriculture revealed that microwaved broccoli lost up to 97% of its beneficial antioxidants, in contrast to steamed broccoli, which lost 11% or less of its antioxidants. Photo: AFP

• A 1998 Japanese study by F. Watanabe showed that just six minutes of microwave heating turned 30%-40% of the vitamin B12 in milk into an inert (dead) form.

• In a study on garlic, as little as 60 seconds of microwave heating was enough to inactivate its allinase, garlic’s principle active ingredient against cancer. (From the Journal of Nutrition, 2001)

• A study of the cooking of asparagus spears found that microwaving caused a reduction in vitamin C. (From the Acta Agriculturae Scandinavica)

But food damage is not the only thing to be concerned about.

Packaging that is microwaveable is usually made with a myriad of chemicals like benzene, toluene, polyethylene terpthalate (PET), xylene and dioxins.

At high temperatures, even though the packaging is supposed to be microwaveable, it is likely that chemicals might still leak into the food, and intake of these chemicals presents a health risk.

One of the more hazardous chemicals used in microwavable food is BPA, a plastic that mimics the oestrogen hormone and could cause problems like infertility, low libido and mental disorders.

Practical alternatives

All you need to survive without your microwave is to make some changes in your food habits:

• Plan ahead. Take the meats you want to cook out of the freezer the night before so that you don’t have to defrost your food in the microwave right before you plan to cook it.

• Prepare your meals in advance so that you always have ready-cooked meals available on the days that you’re too busy or too tired to cook.

• Use a toaster oven to heat up your foods instead. Another option is a convection oven. Both are safe for heating food and are relatively inexpensive appliances.

• Try to add more organic raw food to your diet. There is no need to reheat raw foods, and this is the best way to improve your health over the long run.

Research from the last 30 years on the impact of consuming microwaved food has not been very substantial, but we do have a clearer understanding of how microwaves affect proteins, antioxidants and overall nutritional content of food.