Lifestyle tips for avoiding life-threatening cancer

Avoid obvious carcinogens

Rather obvious, given media coverage over the last 40 years, but anything that you allow to invade your body which isn't actually nutritious or helpful in some way - like nicotine smoke (the most common example), or car exhaust fumes, or workplace chemicals (and so on) - can all help throw cell division into a serious spin. You can see this not only in the huge number of smokers who end up dying of lung cancer, but also in the skin of smokers, in that cell walls throughout their body are harmed, ageing prematurely.

Even strong sunlight can cause cell damage and eventually skin cancer, with the strong ultraviolet rays disturbing cell DNA, though at least skin cancer is one of the most obvious and more treatable forms because it's, by definition, on the outskirts of the body.

Eat healthily and exercise

Although the main benefits of good diet and adequate exercise are the heart and lungs, a stronger, fitter body will also usually have a stronger, more resilient immune system. As previously explained, part of the immune system's function is to provide natural killer cells that go after mutated cells that might turn into cancer. So the stronger your immune system is, the lower the chances of your body developing tumours.

Contrary to urban myth, there's little benefit in concentrating on vitamin and mineral supplements, as the body simply can't process more than small amounts of these and overdoses may even do harm. Instead, focus on fresh fruit and vegetables. They contain not just vitamins but thousands of 'phytochemicals', whose natural benefits are still being discovered today.

And if you exercise outdoors, at least (moderately) in the sun, your skin will produce Vitamin D naturally - this plays a key role in the body's immune system and defenses, protecting against many common cancers, including breast, prostate and colon. Plus you also get extra melatonin produced, which can also help with the immune system and its cells (see below, under 'sleep').

In addition, watch the quantity of food and your weight - excess fat releases chemical signals that interfere with your body's immune system.

Go easy on the alcohol

Moderate to excessive consumption (more than a couple of units a day) can cause problems, since alcohol breaks down in the body to create acetaldehyde, which can cause cancer-related DNA damage. Now, the body contains an enzyme called alcohol dehydrogenase, which quickly converts acetaldehyde to acetate, a relatively harmless substance, but the higher the alcohol intake the more acetaldehyde which hangs around.

Sleep better and longer

In research at Stanford, David Spiegel has suggested two possible ways in which your normal sleep pattern can influence cancer progression. During sleep:

1. the brain produces melatonin, 'part of a class of compounds called anti-oxidants that mop up damaging free-radical compounds'. If you're not sleeping well (or not long enough), the body produces less melatonin and cell DNA is thus more prone to mutations.
    
   
2. cortisol is produced, a hormone which is at peak level at dawn (i.e. immediately after sleep) and then declines throughout the day. Cortisol is one of the main hormones that help regulate immune system activity, including the activity of the cancer-battling natural-killer cells.

Avoid stress

Be vigilant for problem signs

This is hard, since many cancers present no symptoms in their early stages (sadly), but there are still things you can look for:

• unexplained weight loss or constant tiredness
• unexplained lumps or swollen lymph nodes
• persistent coughing
• blood in your stool