As humans, we are all desperate to live forever, or at least as long as possible. It’s very understandable—no one wants to deal with the inevitability of their own mortality—and has given rise to countless movements over the years to extend human life span as much as possible, from schemes involving the blood of young people to cryonic freezing, in which people elect to preserve their bodies so that they may one day be brought back from the dead. Perhaps more appealing than those options, but potentially as iffy: Blue Zones, which are the subject of a recent Netflix documentary.
Blue Zones are regions of the world where people live startlingly, almost magically, long lives. As the story goes, a group of intrepid researchers went looking for the oldest people in the world at the start of the 21st century. They found five places with astonishingly high rates of centenarians and supercentenarians—people who live beyond 100 and 110 years, respectively. Those places are Loma Linda, California; Ikaria, Greece; Sardinia, Italy; Okinawa, Japan; and Nicoya, Costa Rica. To give you an idea of the promise of Blue Zones, the original investigation into Sardinia found that the region had a rate of people aged over 100 years that was about 15 times higher than the Italian national average. (And it wasn’t because centenarians were flocking to Sardinia late in life to be in some super old-folks home.)
On the basis of these findings, an entire industry of health recommendations has been built. There’s a Blue Zone diet, recommending a “daily dose” of the “consummate superfood” (it’s just beans). The official Blue Zone website recommends the “Power 9” combination of behaviors to increase your longevity. There are literally hundreds of studies that have been inspired by the concept of Blue Zones, including clinical trials.
But there’s a problem here. This entire idea is based on the finding that certain areas of the world have incredibly old people. Much older than you’d expect. In fact … suspiciously old.
One explanation for this is that there’s something magical about certain regions of the world and how incredibly disparate groups of people behave. But there’s a simpler explanation: Blue Zones don’t really exist.
This idea comes from Oxford University demographer Saul Newman. In a preprint posted on BioRxiv (that means it hasn’t yet been peer-reviewed), he notes that the regions that have been deemed Blue Zones are surprising places to see a high population of very old people.
Take Okinawa, Japan. According to the Netflix docuseries, it is famous for high consumption of purple sweet potatoes and a sedate, family-oriented lifestyle. These unique features of the region are credited with adding to the longevity of the population. But if you look at Japanese national statistics on the area, the things that stand out are far less rosy. Okinawa leads Japan in child poverty, infectious disease prevalence, and murders per capita. Virtually every statistic I could find showed dramatically higher rates of negative health outcomes for Okinawa than other areas of Japan. Even the dietary claims are odd. The proponents of Blue Zones claim that such areas have very low consumption of meat and processed foods—but Okinawans lead the nation in consumption of Spam, and have the highest concentration of KFC restaurants of any area of Japan.
It is hard to square these facts with the grandiose claims that you can live an extremely long time by copying the way of life in a Blue Zone.
Are people in Okinawa living longer than the rest of us despite the prevalence of KFC and infectious diseases? Maybe purple sweet potatoes are just that good. Newman has another explanation—bad data.
The problem with trying to determine how many very old people are alive in an area is that the further back you look to verify ages, the worse the records get. It’s reasonably easy to figure out where and when a person was born if they are 80. But when we’re talking about 110-year-olds, the records are decidedly patchier. (The supercentenarians at the start of the Blue Zones study were born in the late 1800s.)
And if you look at the databases of the very oldest people that we have on the planet, some striking things emerge. For example, take the U.K. If you were to guess at the place with the most very-long-lived people in the country, you’d probably posit one of the extremely wealthy areas of London such as Westminster or Chelsea, or one of the other rich places in the southeast. You might stretch a guess to somewhere more rural, where the clean countryside air assists with better health.
You’d be wrong. The place with the highest concentration of very old people in the U.K.—the country’s Blue Zone, so to speak—is, according to Newman’s analysis, Tower Hamlets. This is an area of London best known for both poverty and an extremely high rate of violent crime. It’s difficult to prove either way, but it seems more likely that poor record-keeping is at play than that Tower Hamlets is magically conducive to longevity.
There’s even some solid evidence that the rate of supercentenarians in a given area can be due to bad data. If you look at the Gerontology Research Group’s database of supercentenarians and compare it to the years in which U.S. states introduced full birth registration, you see a startling pattern. People who claim to be very old are mostly born before birth registration became statewide—afterward, the rate of 110-plus-year-olds drops by a staggering 80 percent per year. One good example is the state of California. There are 12 people in the GRG database who were born in California, but curiously none of them were born after the year 1900, when the state fully implemented birth registration.
In other words, once places in the U.S. started properly gathering data on births, the rate of very, very old people declined dramatically. That this happened by coincidence is extremely unlikely. What seems more probable is that there’s sloppy record-keeping in the mix.
The problem, of course, is that all of this is still very uncertain. It is not impossible for the rate of supercentenarians to coincidentally decline because of some other factor after better birth registration. Nor is it impossible for a high murder rate to somehow predict longer lives. It’s just very unlikely.
Even if we take the idea of Blue Zones at face value, a recent paper from the journal Demographic Research provides some new and very interesting data on their nature. The region of Nicoya in Costa Rica—one of those original Blue Zones—appears to no longer be a place where people live longer lives than usual. Not only is the Blue Zone apparently limited to a small region, its effects are limited to men born between 1905 and 1930. That means to live like a person in this supposed Blue Zone, you would have to figure out what exactly they were doing in the early 1900s that was so different from people just a decade younger. Perhaps, with digging, you’d be able to figure out a good lesson or two. But it might just be easier to stick to practices that we know can help people stay healthy, like eating a regular old balanced diet.
