COMMENT:

If you Google "what causes cancer" you'll probably scare yourself silly.

You may read, for example, that canned food is "full of preservatives and other substances" that may increase your chance of developing cancer.

Refined sugar is described as a "main culprit" in cancer-causing diets, and white bread is also on the scary list. So are random things such as farmed fish, microwave popcorn and vegetable oils.

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It's possible that if you ate nothing but white bread sprinkled with white sugar you'd be at higher risk for cancer. But the evidence seems scant that any of the other things is going to significantly shorten your life. For the record, there's little evidence that antiperspirant, cellphones, power lines or hair dye cause cancer either.

We do know, though, that according to the World Health Organization up to half of cancers are preventable.

So if it's not about avoiding microwave popcorn, what should we be doing?

It turns out it's actually not that hard to live a low-risk life in terms of cancer, and we might be worrying about the wrong things. So yes, buying organic food is nice, but it's probably not going to save us, if we're not doing the big things right.

The big thing that tops the list is smoking.

We all know the deal with smoking. It's the single biggest risk factor for cancer; it causes at least 15 different cancers and around half the people who smoke are going to die from it. Just don't do it.

Next on the WHO's list of things to address to prevent cancer are ones that affect many more of us: physical inactivity, obesity/overweight and food.

There's a known link between overweight and obesity and many types of cancer including oesophagus, bowel, breast and kidney. Losing weight or maintaining a healthy weight, apart from the other benefits it gives us, is a useful start to lowering cancer risk.

There's good evidence to show that higher levels of activity are linked to lower risk of some cancers: bowel, breast and endometrial cancers show the strongest links.

There's also research showing inactivity - too much sitting, for example - is a risk factor for cancer as well as some other chronic diseases. We're advised to get at least 150 minutes a week of moderate-intensity exercise, 75 minutes of vigorous exercise or a mix of both.

That's quite a lot, but the main point is, moving matters. Anything is better than nothing.

And then of course there's food. Eating for a healthy weight is going to naturally mean we eat less processed foods high in sugar, unhealthy fats and salt - less junk. The WHO says that diets high in fruits and vegetables "may have an independent protective effect against many cancers" - yet another reason to load up our plates with piles of colourful veges and focus on whole foods.

Niki Bezzant is editor-at-large for Healthy Food Guide www.healthyfood.co.nz