Valter Longo, who directs the Longevity Institute at the University of Southern California, has spent years conducting research in Sardinia in an attempt to pinpoint how so many residents live into their 90s and 100s, CBS News reports.

Consider the following: there are 534 people who are 100 or older, or 33.6 for every 100,000 Sardinian residents, The Guardian reports.

In Villagrande, Sardinia, 10 percent of people reach the age of 90. In mainland Italy, that percentage dwindles to 3 percent.

In Perdasdefogu, Sardinia, the number of centenarians is 13 times the national average.

Stats such as these are extraordinarily rare, and researches attribute it to a variety of factors.

For instance, the Sardinian diet consists mostly of pecorino cheese (rich in omega-3), beans, garden vegetables, fruits and whole grains; meats are usually reserved for Sunday dinners and special occasions.

Inhabitants traverse the island’s mountainous terrain on a daily basis, and many spent their lives performing labor-intensive jobs as either farmers or fisherman.

Many of the nonagenarians and centenarians still live active iives, laboring in their gardens and kitchens.

Researchers have gathered that genetics certainly play a part, but they also point to historical events, like World War II, where Sardinians were forced into prolonged periods of fasting due to a lack of food.

They also point to how Sardinians strive to mitigate stress in their daily lives.

However, as of now, the precise facts behind Sardinia’s “fountain of youth” remain a mystery as scientists and gerontologists continue their work to crack the code.

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