HORIZON
BBC2, 9pm

According to Horizon, the secrets of living to be 101 while also remaining hale, hearty and independent are surprisingly straightforward. For instance, it helps on average by five to seven extra years if you adhere to a religious faith.

Horizon's assorted experts reckoned this was because those whose faith allows them to divine life's ultimate purpose go on to live a happier, longer life. There was no mention, however, of the phenomenon of the dull Sunday sermon (sitting through one doesn't actually make you live longer; it just feels that way).

Marge Jetton, 103, was a fine advert for the non-smoking, non-drinking, largely-vegetarian Seventh Day Adventist church. Marge lives in the US's longest-lived town, Loma Linda, California.

Marge lifts weights every day and cycles six miles before breakfast on an exercise-bike. As Marge cheerily asserted: "If you don't have sump'n that hurts ya, why, it's not worthwhile."

In addition, steer clear of stress.

Adopt a "Don't worry, it'll work out" attitude. Reside in a supportive, tight-knit, like-minded community.

There's much to be said, too, for following the rainbow diet which sustains the unusually large number of centenarians - 900 - currently to be found on the Japanese island of Okinawa. Rainbow diet? Anti-oxidising colour is good on your plate: fresh home-grown greens, purple sweet potatoes, carrots, red peppers. Lots of tofu, too. No meat.

Most importantly, the wiry and ageless Okinawan old-timers only eat until they feel 80% full, getting by on 1200 calories a day, roughly one-third to a half less than the official recommendation for westerners. In contrast, the centenarians' lardy grandchildren, gorging on beer and fatty foods, are now engaged in reducing Okinawa's life-expectancy rate.

In more scientific terms, Horizon's researchers found that the undying Japanese oldsters' bodies possess more of one specific hormone. It's a hormone that's a precursor to oestrogen and testosterone. It's produced by the adrenal gland, and in regular folk, it decreases with age. On Okinawa, however, this stuff decreases more slowly.

It's identified as DHEA. If the island's bosses ever want to market its appeal, they could surely do worse than: "Okinawa - our DHEA keeps death at bay."

They do things differently in rural Italy, of course. In the long-living town of Ovodda on Sardinia, there is no calorie-counting and much quaffing of red wine. Extended families enjoy communal accordion-playing and nasal close-harmony singing in restaurants.

In Ovodda, vegetarians are ridiculed. Above all else, good breeding is vital - preferably with folk in the few other families native to Ovodda. This was confirmed by a fleeting street-corner interview with a tight-knit group of healthy sixtysomething local men.

Keeping admirably straight faces, the men all insisted they were each others' uncles. A lone exception was identified as a cousin. Whatever the truth of such claims, the men's heads all seemed to sport the same flat cap.

Ovodda's long life was down to genetic in-breeding, creating a deficiency of bad enzyme G6PD. At the other end of the life-expectancy scale lurked G13, G14 and G15: postcodes which identify Drumchapel, home to a health-challenged middle-aged couple being studied by Greater Glasgow Health Board.

But the Drum's short-lived natives aren't all killing themselves with pies, Buckie and fags, honest. Rather, the same heightened immune-system response which helped over-crowded Glaswegian weans resist childhood infections in the 1950s is now attacking their adult bodies.

Marge Jetton proffered the last word on living longer. Does it confer extra wisdom? Marge was asked. No, she replied, it just gets her more pleasing attention.