Do microwave ovens cause cancer, and other common myths about cancer

Cancer Council NSW

When it comes to cancer, you’ll find no shortage of theories about causes, symptoms and cures. But many of these claims are just myths not supported by science. They cause unnecessary worry and be a barrier to proper prevention and treatment.

It’s important to sift fact from fiction by looking for credible information from trusted sources such as

We’ll bust three common myths about cancer and reveal the truth behind them.

Fact: Microwave ovens do not cause cancer

Microwaves are an essential kitchen appliance for many of us, but is this seemingly innocent tool potentially giving us cancer?

The answer is no. Microwave ovens use microwave radiation to heat food, but this does not mean that they make food radioactive.

Microwaves heat food by causing water molecules to vibrate and, as a result, food is heated. This is different from the absorption of heat energy by food which is the basis of conventional cooking.

Fact: Drinking water from plastic bottles does not cause cancer

People often reuse plastic bottles for drinking water. A common claim is that doing so causes cancer, especially if it’s been left in cars or frozen.

This is false. Plastic bottles are safe to drink as they do not contain dioxins which cause cancer.

If they have contaminants in them, they are likely to be found at tiny concentrations. However, bacteria and fungi can grow in bottled water if they have been left for a long time. So, make sure you clean them with hot, soapy water and dry them before refilling them.

Fact: Food preservatives do not cause cancer

A common misconception is that all or some food additives are harmful and can cause cancer but there is no evidence to prove this.

Food preservatives, or additives, are added to food improve its quality, preserve it or improve the texture and taste of food.

The use of food preservatives is regulated by Food Standards Australia and New Zealand which does extensive testing to ensure that they are safe for consumers. This means you can rest assured that the food products available in our country do not increase your risk of cancer.

Risk factors for cancer

As you can see, there is no evidence that microwaves, plastic bottles or food preservatives do not cause cancer. That said, around one third of all cancers diagnosed in Australia are associated with known risk factors.

Of that one third, most are caused by a remarkably short list of factors. Most are behavioural. The leading causes of cancer associated with lifestyle factors are:

  • tobacco smoking
  • exposure to UV radiation
  • poor diet
  • being overweight
  • physical inactivity
  • alcohol consumption.

Check your cancer risk by doing our quiz.

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