SARDINIA, Italy — Zelinda Paglieno, who turned 102 in October, offers sobering advice when asked what’s the secret to her long and healthy life: “Two fingers width of red wine, and no more, at lunchtime every day.” 

“I’ve never smoked, but a little wine is good for you — and that’s something I still do now. We have very good grapes here,” she explained.

Paglieno’s age is no anomaly here in picturesque Sardinia, an Italian island in the Mediterranean that is home to the oldest people in the world, according to researchers on aging.

Sardinia is one of only five “Blue Zones” in the world identified as having residents who often reach age 90 or older. The other four are Okinawa (Japan), Nicoya (Costa Rica), Icaria (Greece) and the Seventh-day Adventist community in Loma Linda, Calif.

Paglieno, in her hometown of Esterzili, population 600, has three neighbors who are 100 or older.  

Despite her age, Paglieno remains in good health and happily navigates the hilly mountain village she’s lived in her whole life. She attributes her longevity to living off the land, good old-fashioned hard work, destino (destiny) and, of course, the local red wine known to be rich in polyphenols, which offer numerous health benefits.

Researchers studying centenarians in Sardinia’s remote mountain areas have a different explanation.

“Genetics is the main thing. The individuals living to these ages are almost always related,” said Pino Ledda, lead researcher of the Blue Zone Project in the region.

He points to charts on his computer about the nearby village of Seulo, a few miles from Esterzili on an adjacent mountainside, that had 20 centenarians over the past two decades.

“These areas are…