I wouldn't say I've courted cancer exactly, but I have hitherto been pretty heedless of the warnings. Now, however, I have reached a stage in life where I think it may be time I stopped meeting cancer halfway. Fresh from a three-week holiday that combined lashings of alcohol, lashings of stress, plenty of sun, a good deal of red meat, a lot of passive smoking and a certain amount of aggressive smoking, I think perhaps I should try to be a little less helpful to cancer. At the very least I could avoid known carcinogens, even if for just one day. I resolved to give it a try.

My first mistake came shortly after waking up. Toothpaste, I have since discovered, contains several compounds (fluorides and sodium lauryl sulphate among them) that are at least suspected carcinogens, as do shaving cream, soap and shampoo. Breakfast, as well as being the most important meal of the day, is also a cocktail of cancer-causing substances. Heterocyclicamines - highly mutagenic, possibly carcinogenic - are created by cooking or burning foods, and are commonly found in coffee and toast.

Aflatoxins, produced by naturally occurring fungi, are found in small concentrations in milk and cereal. Aflatoxin B1, the most deadly of all the aflatoxins, has been shown to cause cancer in mice, rats, hamsters, rainbow trout, ducks, marmosets (this is a partial list, by the way), tree shrews, guinea pigs and monkeys. Luckily, breakfast is not the most important meal of the day to me, so I'm happy to skip it.

It quickly becomes clear that total carcinogenic abstention is more difficult than it sounds. When that noted oncologist Joe Jackson first proclaimed that "Everything/Gives you cancer", I think most people understood him to be speaking about all the good things in life -smoking and drinking and red meat and DDT-based pesticides. But a quick look at even a partial list of known human carcinogens proves that he may as well have been speaking literally.

Going out in the midday sun presents an obvious risk, but thanks to the radon seeping into your home from the soil below, so does staying indoors. Taking to the air is no better: high-altitude flights routinely expose passengers and crew to radiation, and the free peanuts, with their traces of carcinogenic fungal toxic metabolites, aren't much help either.

Shortly after not having breakfast, I decided to retreat to my office at the very top of the house, the furthest I can get from cancer without getting cancer, where I read up on the 15 known carcinogenic substances commonly used in roofing material.

Hunger eventually drove me back to the kitchen, with an eye towards whipping up a cancer-free salad, but here again there was no escape. While the risk of getting cancer from fruit and vegetables remains small, most of that risk is said to come from naturally occurring carcinogens, generally the organic pesticides produced by the plants themselves to keep predators at bay. Broccoli, apples, onions, oranges, strawberries, lemons and mushrooms all contain acetaldehyde, a natural by-product of oxidation and a known human carcinogen. If you close your eyes you can practically taste it.

Nitrates - which can be converted by the human body into carcinogenic nitrosamine compounds - are present in such seemingly inoffensive foods as celery, lettuce, kale and rhubarb. Nitrites, halfway to being nitrosamines already, are found in cured meats. There are carcinogens specific to tap water, basil, beer and mustard. Cancer-causing PCBs are found in varying levels in all foods. It is generally accepted that there is no such thing as a diet free from carcinogens, so there's no point in worrying about it, although it is unclear how the second part follows from the first.

It's well known, of course, that certain foods have anti-carcinogenic properties: organosulphur compounds, flavonoids, tannins and carotenoids have been shown to inhibit some forms of cancer. Unfortunately, these anti-carcinogens tend to be found in foods that also contain carcinogens - well-known killers such as broccoli, onions, strawberries and cabbage. Even while these vegetables are preventing you from getting cancer, they are giving you cancer.

Ingesting carcinogens directly is now regarded as a rather old-fashioned way of getting cancer. These days, simply exposing oneself to one's environment for prolonged periods - what used to be known as standing around minding your own business - is plenty carcinogenic enough. Diesel exhaust, asbestos, the formaldehyde in ordinary home air and crystalline silica of respirable size (ie dust) have all been listed as carcinogens.

You can get cancer from the wax on your floors, the paint on your walls and the dyes in your shirt. We are all constantly exposed to vinyl chloride, a gas emitted by PVC plastic, which is sometimes known as new-car smell. Then there is isoprene, which the US National Toxicology Programme describes as "reasonably anticipated to be a human carcinogen". Isoprene is emitted by rubber products (natural and synthetic), automobiles and trees, and is commonly found in exhaled human breath. When you breathe in you get cancer; when you breathe out, you give it to someone else.

The popular idea that absolutely everything gives you cancer is finally confirmed by the fact that many cancer treatments, such as cisplatin, are themselves known to cause cancer. So even while you are dying of cancer, you may also be getting cancer. This is somehow a less worrying prospect, a bit like finding out that mustard gas is carcinogenic (which it is).

If you are ever unsure as to whether something you're doing or eating or inhaling is giving you cancer, the internet is always there to confirm your worst fears. Go to any search engine, type in the name of any common product or substance (herbal tea, nail polish, jellied eels, fabric softener), then type in cancer and hit the return key. You won't be disappointed.

Ultimately, however, this notion that all things are carcinogenic is misleading; risks vary wildly depending on dose, length of exposure and countless other factors. Most "known carcinogens" have only been tested on animals, in huge concentrations. Some of these substances cause tumours in mice, but not in rats or hamsters. In any case, most of them are unavoidable. You can't stop drinking water, or breathing air.

In short, one can do little to avoid cancer apart from the obvious: the vast majority of preventable cancers are caused by smoking, drinking and poor diet, which also just happen to be the major causes of dying from things other than cancer. Mildly carcinogenic vegetables are the least of your problems, and it's doubtful that anyone ever got cancer solely from eating broccoli. But because luck also appears to play a big part, cancer tends to inspire more superstition than any other disease. I realise I'm running a huge risk of contracting cancer just by writing about it. I think I'll stop here.