In short: the Nicoya Peninsula is one of the five “blue zones” identified worldwide—regions where a large number of very old people have been recorded. Research by demographer Luis Rosero-Bixby confirms that Nicoyan men born before 1930 lived significantly longer than other Costa Ricans. However, this advantage diminishes among younger generations, and some of the longevity records can be attributed to errors in civil registration records. The Nicoyan lifestyle remains healthy: a plant-based diet, daily physical activity, strong social ties, and mineral-rich water.
Sardinia, the Greek island of Ikaria, Loma Linda in California, the Japanese island of Okinawa, and the Nicoya Peninsula in Costa Rica: these five regions share a common reputation. They are said to have more very elderly people than anywhere else. The concept of the “Blue Zone” is fascinating, but it’s also a subject of debate among scientists. Here’s what the research confirms, what it qualifies, and what travelers can take away from it.
Where does the term “blue zone” come from?
The term originated in Sardinia. In the early 2000s, demographers Michel Poulain and Gianni Pes identified a mountainous area where an unusually high proportion of men lived to be 100 or older. They circled the region in blue on their map, hence the name. Journalist Dan Buettner then popularized the concept among the general public, first through National Geographic and later in his book *The Blue Zones*.
Five regions are identified in this framework. According to Buettner, they share a set of lifestyle habits that researchers subsequently sought to evaluate. It is on this point that science offers conflicting answers.
A simple, healthy, and—above all—plant-based diet
Journalist Dan Buettner, author of*The Blue ZonesSolution*, has focused in particular on the diets of the residents of these five “Blue Zones.” He explains that they share several common traits, such as “eating the smallest meal of the day in the afternoon or evening” and “consuming very little meat and dairy products.”
Furthermore, the journalist notes that each Blue Zone is characterized by the consumption of foods that appear to promote longevity.
On the Nicoya Peninsula, the traditional diet is rooted in Mesoamerican agriculture. The “three sisters”—beans, corn, and squash—form the foundation. These are complemented by tropical fruits such as papaya, plantains, mangoes, and guavas, along with moderate meat consumption and few processed foods.
Buettner also observed that residents eat their main meal at noon and a light dinner in the evening. These observations describe a diet consistent with modern nutritional recommendations. They do not, on their own, prove a cause-and-effect relationship with longevity. Papaya, for example, provides antioxidants, fiber, and vitamin C, but no serious study has attributed a significant effect to it in reducing the risk of cancer.
Regular physical activity
Physical activity also appears to contribute to the exceptional longevity in these regions. Centenarians do not necessarily engage in intense physical activity, but they naturally move their muscles on a daily basis, particularly through relatively physically demanding work.
Moving and Staying Active Every Day
The very elderly in Nicoya do not engage in intense physical activity. They move naturally throughout the day. Working on the farms, walking, gardening, and taking care of the house and animals help maintain muscle mass and mobility. This regular, moderate physical activity is a common feature across the five Blue Zones.
Strong social ties and a “plan de vida”
The social factor is one of the best-documented. Communities in Nicoya place a central role on their elders, who remain actively involved in family and community life. Many speak of a “plan de vida,” a reason to get up in the morning. The sense of purpose and belonging helps reduce chronic stress, a recognized risk factor for mortality. Their Chorotega roots and religious life reinforce this support network.
Nicoya’s Hard Water: A Promising Biological Approach
Water in Nicoya seeps through limestone and becomes enriched with calcium and magnesium. A study by the Technological Institute of Costa Rica, based on thousands of drinking water analyses in Guanacaste, examined the link between water hardness and life expectancy by district. These minerals contribute to bone strength and may reduce the number of serious hip fractures among older adults.
Biological markers were also measured. A study conducted with Stanford University as part of the CRELES cohort showed that residents of Nicoya had longer telomeres—the ends of chromosomes associated with slower cellular aging and lower stress levels. Other studies have identified differences in DNA methylation that may reflect slowed aging. These results remain hypotheses, not definitive proof.
Spotlight on Nicoya: What Demographic Studies Reveal
Costa Rica has a life expectancy of nearly 80 years, the highest in Central America according to the World Bank. On the Nicoya Peninsula, this trend has long been even more pronounced. Using death records and electoral data—which are more reliable than census reports— Luis Rosero-Bixby and his colleagues estimated that, between 1990 and 2011, elderly men in Nicoya had a mortality rate approximately 20% lower than that of other Costa Ricans.
This finding is based on the CRELES (Costa Rican Study on Longevity and Healthy Aging) cohort, which has been tracked since 2007. For the oldest generations, the remaining life expectancy of men from Nicoya even exceeded that of Japanese men of the same age, the global benchmark for longevity. It is this demographic foundation that has earned Nicoya its status as a Blue Zone.
Is Nicoya’s advantage fading?
Yes, to a large extent. In 2023, Rosero-Bixby published an analysis in the journal Demographic Research based on a sample of 550,000 Costa Rican adults tracked between 1990 and 2020. The conclusion is clear. The Nicoya advantage is fading with each generation.
Men from Nicoya born in 1905 had an adult mortality rate 33% lower than the national average. Those born in 1935 had only a 4% advantage. In contrast, those born in 1945 had a mortality rate 10% higher than the national average. The historic hotbed of longevity has shrunk to a small area in the south of the peninsula, along the corridor stretching from Hojancha to Sámara Beach. Nicoyans born before 1930 who are still alive remain exceptional, but the window of opportunity to study them is closing.
The Controversy: Blue Zones Called into Question
The concept itself has been seriously challenged. In 2024, demographer Saul Justin Newman of University College London received the Ig Nobel Prize in Demography for work showing that many records of extreme age are based on flawed data. Errors in civil registration, missing birth certificates, and pension fraud are believed to account for a significant portion of these cases.
Costa Rica is directly affected. In 2008, an audit revealed that 42% of Costa Ricans reported to be 99 years old or older had provided an incorrect age during the 2000 census. After partial correction, the Nicoya Blue Zone would have shrunk by about 90%, and life expectancy at advanced ages would have fallen from a record high to a much more ordinary level. Newman also points out that Blue Zones often correspond to poor regions, where records are unreliable.
This criticism does not mean that no one lives to a ripe old age in Nicoya. It serves as a reminder that the most spectacular figures must be treated with caution. This is precisely why Rosero-Bixby’s work, based on death records, retains its value: it confirms a genuine trend among men of older generations, while showing that this trend is waning.
Factors Contributing to Longevity in Nicoya: A Review of the Evidence
| Factor | What the researchers observed | Strength of evidence |
|---|---|---|
| Low mortality among older men (generations born before 1930) | Approximately 20% lower mortality from 1990 to 2011, according to death records (Rosero-Bixby) | Strong |
| Decline in the benefit among younger generations | Cohort effect: men born in 1945 have a mortality rate 10% higher than the national average | Solid |
| Hard water rich in calcium and magnesium | Correlation between water hardness and longevity, stronger bones, and fewer fractures | Plausible |
| Longer telomeres, lower stress | Markers of slowed cellular aging measured in the CRELES cohort | Plausible |
| Plant-based diet and light dinner | Diet consistent with modern nutrition, but no proven causal link | Plausible |
| Very high number of centenarians | Overestimated due to errors in civil registration and inaccurate age reports | Controversial |
So, should we believe in the secret of Nicoya?
The honest answer is nuanced. Nicoya is not a fountain of youth, and the records for centenarians have been overestimated. But a real longevity advantage did exist for older generations, and the local lifestyle remains conducive to good health: a simple diet, gentle daily physical activity, close family ties, and low exposure to urban stress.
These are principles anyone can adopt, without having to travel to the other side of the world. And if you’d like to explore the region, the peninsula offers much more than just a scientific label. Its beaches in Guanacaste and Nicoya, its Chorotega culture, and its peaceful way of life—the famous “Pura Vida”—are worth the trip in their own right.The annexation of Nicoya by Costa Rica, celebrated every July 25, speaks volumes about its unique identity.
Frequently Asked Questions
Is Nicoya really a Blue Zone?
Nicoya has been recognized as a Blue Zone based on demographic data showing low mortality rates among older men. This trend is confirmed by death records for generations born before 1930, but it becomes less pronounced among younger generations.
Why do the people of Nicoya live so long?
Several factors are cited: a plant-based diet consisting of beans, corn, and squash; daily, moderate physical activity; strong social ties; a sense of “plan de vida”; and water rich in calcium and magnesium. None of these factors alone is sufficient.
Is the concept of a “Blue Zone” scientifically sound?
It is disputed. Demographer Saul Justin Newman demonstrated in 2024 that many records of extreme longevity are based on civil registry errors or fraud. The most robust studies, however, which are based on death records, remain valid for Nicoya.
Can you visit the Nicoya Blue Zone?
Yes. The Nicoya Peninsula, in the province of Guanacaste, is easy to visit during a trip to Costa Rica, with its Pacific beaches, traditional villages, and unspoiled nature.
À propos de l’autrice
Jenna, conceptrice voyage chez Terra Caribea, proche des communautés locales. Notre agence francophone, basée à San José, construit des séjours sur mesure au Costa Rica, y compris à la découverte de la péninsule de Nicoya et du Guanacaste.
Sources scientifiques
- Poulain M., Pes G. M. et al. (2004), « Identification of a geographic area characterized by extreme longevity in the Sardinia island: the AKEA study », Experimental Gerontology.
- Rosero-Bixby L., Dow W. H., Rehkopf D. H. (2013), « The Nicoya region of Costa Rica: a high longevity island for elderly males », Vienna Yearbook of Population Research.
- Rehkopf D. H., Dow W. H., Rosero-Bixby L., Lin J., Epel E. S., Blackburn E. H. (2013), étude sur la longueur des télomères à Nicoya, Experimental Gerontology. Synthèse : Stanford Medicine.
- Rosero-Bixby L. (2023), « The vanishing advantage of longevity in Nicoya, Costa Rica: A cohort shift », Demographic Research, vol. 49, art. 27 : demographic-research.org.
- Newman S. J. (2024), « Supercentenarian and remarkable age records exhibit patterns indicative of clerical errors and pension fraud » (prix Ig Nobel de démographie 2024) : University College London.
- Ramírez Leiva A. et al. (2015), étude sur la dureté de l’eau et la longévité dans la péninsule de Nicoya, Revista Tecnología en Marcha, Tecnológico de Costa Rica : SciELO Costa Rica.
- Cohorte CRELES (Costa Rican Study on Longevity and Healthy Aging), Universidad de Costa Rica.
Article initialement publié en 2020, mis à jour le 31 juillet 2026.
