The IKARIA Study

Why Ikaria?

Ikaria is a mountainous island of about 8,000 people in the North Aegean Sea. Demographers studying population records noticed that an unusually high share of its residents live into their 90s, often in good health. That made Ikaria one of the world's five "Blue Zones", alongside Okinawa in Japan, Sardinia in Italy, Nicoya in Costa Rica and Loma Linda in California.

The natural question was why. In 2009, a team from the University of Athens Medical School set out to answer it.

How the study worked

The IKARIA Study recruited men and women living permanently on the island. Researchers recorded what people ate, how active they were, how they slept, whether they napped, their stress and mood, their family and social life, and a range of medical measurements such as blood pressure, blood tests and the health of their blood vessels.

Most published analyses focus on people aged 65 and over, the group in which Ikaria's longevity is most striking. A follow-up between 2009 and 2013 tracked who developed heart disease and who died, so researchers could look for links between lifestyle and long-term health.

What the researchers found

A traditional Mediterranean diet, closely followed

Older Ikarians scored high on standard measures of Mediterranean diet adherence. Their diet was rich in vegetables, wild greens, legumes, potatoes, olive oil and herbal tea, with modest amounts of fish, goat dairy and wine, and relatively little meat and refined sugar. Higher adherence was linked with healthier markers, including lower uric acid levels in older people without heart disease.

Boiled Greek coffee and healthier blood vessels

One of the best-known findings came from a 2013 analysis of 142 islanders aged 66 to 91. Those who mainly drank traditional boiled Greek coffee had better endothelial function, a measure of how well blood vessels relax and widen, than those who drank other kinds of coffee. The link held even among people with high blood pressure.

Fish and mood

Older islanders who ate fish more often reported fewer symptoms of depression, adding to evidence that diet may affect mental as well as physical health.

Napping, activity and a slower pace

Regular midday naps were common, and most older Ikarians stayed physically active through daily life: walking the island's steep paths, gardening and farming, rather than formal exercise. Low reported stress and a strong sense of community stood out too.

Studying Ikaria's nonagenarians

Later research led by demographer Michel Poulain and colleagues looked specifically at people aged 90 and over in the north-western villages of Evdilos and Raches. In a 2021 paper based on interviews with 71 nonagenarians, more than three in four reported daily social contact, and many remained physically active. Interestingly, the authors found the link with diet less clear-cut in this very old group than in earlier work, which suggests that Ikaria's longevity comes from a combination of factors rather than food alone.

What the study can and can't tell us

The IKARIA Study is observational. It shows what long-lived Ikarians have in common, but it cannot prove that any single habit causes a longer life. Genetics, the island's isolation, clean air and a strong community may all play a part.

What makes it valuable is that its findings match a much larger body of research on Mediterranean diets, legumes, olive oil, physical activity, sleep and social connection. You can read about that evidence on our science page.