This morning I woke with the niggling bastardy little ghost of last night's red wine vibrating through my head and dehydrating my synapses. I soaked them in tannin, applied the usual light coating of carcinogens to my face, and read the news that we're as unhealthy as Americans. Americans? But they're those comically lardy simpletons in sports clothes who require two aeroplane seats each. The tiny per cent of them who have a passport, that is. The few who know there are other countries, apart from Alaska and Hawaii and the "axis of evil". Yes, recent findings prove that we pale, neurotic, black-clad creatures – members of an acned little colony rather than the empire rulers we fondly imagine ourselves to be – are just as unhealthy as that lot. And it's all down to alcohol.

They may be squirting their hormone-raised beefburgers with mayonnaise, but our ways with a bottle – it makes little difference whether it's Buckie-guzzling in the bus stop, or the drip-drip-drip of Costières de Nîmes at the reclaimed rectory table – mean that we're as cancer-prone as the Americans, and thus we've really got to watch it.

I shuddered at the findings and attendant World Cancer Research Fund quotes, hazily remembered stopping drinking for a while after last year's Million Women Study, which showed that even a small glass could help rearrange your breast cells, then calculated that I have quite a few social occasions coming up and that denial may well be the only way forward. This is one horror story too many.

But denial is anathema to us. Denial is our parents' generation's speciality. That generation who survived the second world war or its subsequent austerity and consider us a load of spoilt emoters. Which we are. But of course each generation reacts against the previous one, so to us the oldsters are tragically – even cancer-causingly – repressed: terrifying creatures seething with muffled emotions; grim yet cheerful; glinty and beady, all disapproving half-glances, eerie smiles hiding tears, and nothing said. Save a sausage, rub your corners off, and never mind that thrombosis, dear, it's only suppurating a bit.

Whereas we, the war children's adult offspring routinely see shrinks, talk about our IVF (all those granny-alikes wheeling their girl-boy twins round can't really avoid confessing); air our sobbing psyches to the nation on reality TV or cut-you-into-shape shows, and blame it all on environment or poor attachment. And our children are flexi-sexual emos, their role models given to flashing their fannies at waiting photographers or tweeting about their relationship breakdowns.

So anyone under 60 tends to be not too keen on denial. Or at least conscious denial. But as we get older, and our world more crowded with microparticles and exhortations to fun-free living, so it becomes a tempting option, even to those of us who are proud of our openness.

"Denial's a beautiful thing," says clinical psychologist Dr Cecilia d'Felice. "It's a powerful psychological defence mechanism. We have to operate at a level of denial, otherwise we'd be permanently depressed because we have the one big truth hanging over us: that we're going to die. Eastern philosophies that ask you to contemplate your mortality are not that popular with our culture."

Contemplating denial, Freud talked about "minimisation", in which a fact is admitted but its seriousness denied, and "projection", in which repressed thoughts are attributed to someone else. In fact, the brain remains immature in some areas, barely developing since babyhood, hence our occasional gothically immature reactions. We revert to infantile behaviour and hide our heads under metaphorical blankets.

This morning featured a walk through a tangle of internet, boiler and burglar alarm wireless rays just to boil the kettle, those same waves zinging my soft-boned children. Neighbours' wireless beams and mobile phone microwaves joined the unseen light show. If only they were visible, the ever-more striated airways would resemble a storm of intergalactic laser beams and we'd all be encasing our children in lead. "As parents, we're complete fiends of denial," says D'Felice. "It's not so much about us dying; it's about what we're leaving behind. Denial escalates as we take on more responsibilities in the world."

As a walking cliche, as a predictable example of the nervy and educated neurotic, I obediently limit red meat, coffee and saturated fats, never binge drink, walk miles, wouldn't touch a sunbed, and have never smoked since having a bewildering drag of my mother's fag at the age of nine. But I live out of choice on a metropolitan rat-run, and am existing for two months in a haze of MDF dust while an extension is being built. MDF, according to internet mutterings, is the asbestos of our day. But will I shell out the thousands more for natural wood? Not a chance. And will I move to the country or even to the surrounding scuzzier streets with fewer cars storming down them? No, I won't. Too suburban. And I haven't noticed anyone chucking away their toasters since the discovery that toast contains carcinogenic acrylamide. Thus, toast and inhalation of heavy metals join the family diet of petroleum lip salve and paraben-laced shampoo, yet we'd start screaming if someone brought in a can of Coke for the kids.

This ageing business is another blanket-over-head situation. Watching the documentary film Ballets Russes last week, I winced as ancient ballerinas, octogenarians if a day, retraced sequences from their Diaghilev-era youth dressed in backless leotards and diaphanous tutus, attitudes struck with dove hands and much dewy simpering. The come-hither eyes, the winsome head-tilting, were a yelping embarrassment, yet it was clear they were inhabiting their youthful selves so completely that all sense of their current appearance was lost. We project our old faces on to our new when we see ourselves, the one superimposed on the other in the mirror and the mind. I know exactly which mirrors in my house are soothingly cast in silvery shadow, and which cause me to bolt past, eyes averted from the blast of capillary-exposing reality. I'll take to travelling with paper lampshades like Blanche DuBois.

Foundation and sunblock seem to the conditioned mind entirely necessary, even as their chemicals wriggle silently into our bloodstreams. So we apply the lead of our day, knowingly poisoning ourselves while convincing ourselves we're not. But if everything is either a cause or a cure for cancer, what can we do but blank some of it out? "Humankind cannot bear very much reality," wrote TS Eliot. Would you rather be a cautious puritan or a happy cretin?

The older I grow, the more blithe idiocy seems the route to sanity.

Joanna Briscoe's novel Sleep With Me is published by Bloomsbury.

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