Fact Checking the Data Behind Blue Zones

In recent years, there has been a substantial amount of media attention on “Blue Zones,” communities around the world where many people make it to their 100^th birthdays and beyond. The term was first used in 2004 by a team of researchers led by Dr. Michel Poulain, who discovered that Italy’s Nuoro province on Sardinia had a greater population of male centenarians. [1] They had a map of Italy where they marked more concentrated regions of centenarians with a blue pen—hence the phrase “Blue Zones.”

The research was noticed by an American entrepreneur and expedition organizer named Dan Buettner, who approached The National Geographic Society with an idea to research worldwide longevity hotspots. He identified four more regions: Okinawa, Japan; Loma Linda, California; Nicoya Peninsula, Costa Rica; and the island of Ikaria, Greece. He wrote about all of this in his 2008 book, The Blue Zones: Lessons for Living Longer from the People Who’ve Lived the Longest. [2]

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What Buettner didn’t fully cover in the book was how difficult it was to accurately identify Blue Zones. Researchers who try to identify where the highest concentrations of centenarians are on the planet face unreliable testimonials and incomplete birth records. Poulain used a Gaussian Neighborhood Distribution, which is a means of weighting regions through cluster analysis. In short, it’s an estimation. 

However, since the book focused on “those who’ve lived the longest,” it’s important to differentiate centenarians (those who’ve lived past 100) from supercentenarians (those who lived past 110.) Sardinia, the first Blue Zone, actually only had two supercentenarians.

Admittedly there is a wealth of data from Sardinian centenarian longevity data which has important ramifications for health and wellbeing, however, if we want to learn from “those who’ve lived the longest,” we should examine those people, not the second-best group.

Blue Zones by Supercentenarians

Fortunately, the Gerontology Research Group has verified and kept records of supercentenarians around the world. An examination of the data in 2018 showed a total of 1,617 men and women had been verified. [3] When this list is analyzed, a very different picture of Blue Zones appears.

Top Countries by Number of Supercentenarians per Million People

When countries are ranked by the number of supercentenarians per million people, the top five countries are the United States, Canada, Norway, Australia, and Japan.* When you look at total number of supercentenarians, Italy is still in the top 10 at 8^th place, but Greece is 24^th and Costa Rica doesn’t even make the top 30.

*Note that India, Poland, and Panama are not included in this ranking since data for their populations in 1900 was not available. Further, two countries (Luxembourg and Cape Verde) were excluded due to extremely low population numbers and the subsequent risk of random population variation errors

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As of 2018, an incredible 41.73% of confirmed supercentenarians have lived in the United States. While California was in Buettner’s list of Blue Zones, when U.S. states are ranked by the number of supercentenarians per million, California is a distant 21^st—and not one of California’s 14 supercentenarians lived or died in Loma Linda. The top five states are New Hampshire, Nebraska, Iowa, Maine, and North Carolina.

U.S. States by Number of Supercentenarians per Million People

Clearly, the data indicate the greatest number of supercentenarians reside in the U.S., Canada, Norway, and Australia. These populations should be fundamental in helping guide epidemiologists to discover and unmask the biological basis for extreme longevity in all human groups. Obviously, centenarian longevity data also has an important place in unraveling the foundation for human longevity and should contribute together with the information gleaned from supercentenarians.

How The Paleo Diet® Compares to the Blue Zone Diet

Despite the above data showing a different regional picture when it comes to the greatest longevity, Blue Zone lifestyles remain compelling to those in search of healthy habits. Diets like the Blue Zone diet and the Mediterranean diet have both evolved out of the lifestyles of the people from regions like Italy and Greece. Though a Blue Zone diet does share some similarities to The Paleo Diet, there are also some key differences.

Like those following a Paleo lifestyle, people on a Blue Zone diet cut out dairy and sugar. Both diets are low sodium; restrict processed foods; and are high in potassium, fiber, and nutrients. Both diets also suggest eating sustainable or wild-caught meat and organic produce.

However, according to Buettner, those on Blue Zone diets typically limit their consumption of meat and eggs, which contain important omega-3 fatty acids and other essential nutrients. Another difference is that people following Blue Zone diets eat grains and beans, while The Paleo Diet recommends steering clear of those inflammatory foods.

RELATED: The Paleo Diet Is an Anti-Inflammatory Diet

A Note on Data Collection Practices for Centenarians and Supercentenarians

If you follow research on longevity, you may be aware of a 2024 paper published by Saul Newman in the preprint server for biology, bioRxiv, titled “Supercentenarian and remarkable age records exhibit patterns indicative of clerical errors and pension fraud.” [4]

Preprint articles have not been peer reviewed, and with respect to this article, it is an update to Newman’s original article posted in 2019. Consequently, it should be noted that Newman has not published his research in a peer reviewed journal since 2019. We do not challenge the compiled data of centenarians in Blue Zones, we only state that they do not represent the oldest living humans. [5]

As to the research published by Newman, his original paper was shared on a blog post at Columbia University. If you scroll down, you can see a discussion between Newman and Robert D. Young, Director of the GRG Supercentenarian Research and Database Division. [6] We feel confident in the data compiled by GRG that we used to construct this article.

References

1. Poulain M, Pes GM, Grasland C, Carru C, Ferrucci L, Baggio G, et al. Identification of a geographic area characterized by extreme longevity in the Sardinia island: the AKEA study. Experimental Gerontology [Internet]. 2004 Sep [cited 2020 May 8];39(9):1423–9. Available from: https://halshs.archives-ouvertes.fr/halshs-00175541v2/document
2. Buettner D. The Blue Zones: Lessons for Living Longer from the People Who’ve Lived the Longest. Washington, D.C.: National Geographic Society; Enfield; 2010.
3. Gerontology Research Group – Dr. Coles’ Supercentenarian Institute [Internet]. Grg-supercentenarians.org. 2019 [cited 2024 Nov 1]. Available from: https://www.grg-supercentenarians.org/
4. Newman S. Supercentenarian and remarkable age records exhibit patterns indicative of clerical errors and pension fraud [Internet]. BioRxiv. Cold Spring Harbor Laboratory; 2024 [cited 2024 Nov 1]. Available from: https://www.biorxiv.org/content/10.1101/704080v3.full  
5. Pes G, Rosero-Bixby L, Chrysohoou C, Stefanadis C, Willcox B, Willcox C. Demographers’ Statement [Internet]. Blue Zones. 2024. Available from: https://www.bluezones.com/wp-content/uploads/2024/10/Demographers-Statement-10.2024.pdf   
6. Andrew. Are supercentenarians mostly superfrauds? | Statistical Modeling, Causal Inference, and Social Science [Internet]. Columbia.edu. 2019 [cited 2024 Nov 1]. Available from: https://statmodeling.stat.columbia.edu/2019/08/06/are-supercentenarians-mostly-superfrauds/