What are the Blue Zones and what is actually true about them?

Blue Zones are five regions where a striking number of people reach a very advanced age, often without the chronic diseases so common in the Western world: Okinawa (Japan), the Nicoya Peninsula (Costa Rica), Loma Linda (California), Ikaria (Greece), and Ogliastra in Sardinia. The pattern itself has been established, but which factors precisely make the difference has not yet been conclusively proven.

What researchers find in all these regions is a combination of protective habits. Residents eat predominantly plant-based diets, with plenty of legumes, vegetables, tubers, and olive oil. They move regularly but not intensively, simply as part of their daily lives. They live in close-knit communities with strong family ties and religious or social structures. And they live in relatively clean environments, at some elevation, with little exposure to pollution. All these factors appear to work together, but it is difficult to identify any single one as the decisive cause.

Of the individual elements, walking is most strongly supported by research conducted outside the Blue Zones. Thirty minutes of brisk walking per day, five days a week, reduces the risk of cardiovascular disease, type 2 diabetes, cognitive decline, and premature death. That aligns well with how people in Blue Zones move. The plant-based, polyphenol-rich diet also has positive indications, but the evidence base for this is somewhat weaker and knowledge gaps remain.

Genetics probably plays a smaller role than you might expect. Comparisons of residents in Ikaria and Sardinia with other populations suggest that behaviour and living environment carry more weight than hereditary predisposition. Psychosocial factors, such as a positive self-image, being married or cohabiting, and strong social integration, are associated with a greater likelihood of reaching an advanced age in these regions. Whether this is a cause or a consequence of healthy ageing is not yet certain.

There are also critical caveats. The Blue Zones Projects in American cities, in which municipalities translate the lessons from the Blue Zones into policy, are evaluated positively by the originator of the concept itself, but hard research data are lacking. The role of the gut microbiome as a possible intermediate link is interesting but is still entirely in its infancy and is largely based on indirect indications.