One is a town surrounded by tropical forest and beaches popular with surfers, two are craggy islands in the turquoise waters of the Mediterranean, the fourth is at the tail of the Japanese archipelago, while the last is a small city in California whose name means “beautiful hill”.
At first glance, there might not seem much to link these five locations – Nicoya in Costa Rica, Sardinia in Italy, Ikaria in Greece, Okinawa in Japan and Loma Linda in California. They are scattered in different corners of the world and could not look more different.
But for anyone wanting to live a long and healthy life, these are perhaps the five best places to have been born. These are the so-called Blue Zones, where people’s chances of living to 100 years old is ten times higher than the US average.
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The term Blue Zone first originated with the Italian epidemiologist Gianni Pes and the Belgian demographer Michel Poulain, who were investigating rates of mortality in Sardinia. Marking regions of high longevity in blue in the early 2000s, they found a cluster of particularly high life expectancies in the province of Nuoro on the island. Working with the American journalist Dan Buettner, they since identified a handful of other regions across the world – work that spawned a best-selling book on the subject in 2008.
Getting plenty of daily exercise may be one of the keys to the long life enjoyed by centenarians in Blue Zones around the world (Credit Alamy)
In the subsequent 12 years, many scientists have continued their research into the Blue Zones, with many intriguing hypotheses about what might explain the longevity in these regions.
The lifespan lottery
Let’s first explore the general patterns. As Buettner explored in his original book, the lifestyles of people across the Blue Zones share certain characteristics.
The first is diet. Particularly in the past, many people in the Blue Zones tended to eat in moderation. In Okinawa, for example, the elderly people follow the ancient rule of “Hara hachi bu” – eating only until the stomach is 80% full. (According to scientific studies, that translates to around 10% fewer calories than the current recommendations for the average adult.)
And this seems to slow ageing.
Long-term animal studies by Rozalyn Anderson, who researches metabolism and ageing at the University of Wisconsin, have shown that macaques following similar “calorie restricted” diets and have a markedly lower risk of age-related diseases such as cancer, diabetes and heart disease. They even look younger – the macaques’ fur took longer to turn grey, for example.
In Okinawa, the elderly people follow the ancient rule of “Hara hachi bu” – eating only until the stomach is 80% full
We don’t yet understand the full mechanisms behind these effects, though calorie restriction seems to reduce the build-up of the toxic free radicals that are normally the result of our metabolism, and which can damage our cells. Some scientists have argued that the body also experiences the reduced calorie consumption as a very mild stress, which shifts its signalling to focus on the maintenance of cells (rather than, say, building new tissue).
According to Diddahally Govindaraju, a geneticist at Harvard University, in Boston, Massachusetts, this decreases the risk of forming damaging mutations in our DNA, which could lead to diseases like cancer. “Calorie restriction appears to reduce DNA damage and improve DNA repair,” he says. “And genome integrity appears to be a feature among centenarians.” Besides being fairly frugal, the diets in the Blue Zones are mostly plant-based, which can contribute to greater heart health.
In addition to their eating habits, of equal importance are the social lives these centenarians enjoy: the people in the Blue Zones tend to live in highly integrated communities. It is now well accepted that a sense of social connection helps to reduce the effects of stress, while the responsibility of maintaining those friendships encourages greater overall mental and physical activity. In one meta-analysis, Julianne Holt-Lunstad, a psychologist at Brigham Young University, in Provo, Utah, found that the quality of our relationships are as important to our health as exercise or diet.
Religion offers one important source of social connection in the Blue Zones. The people of Loma Linda are mostly Seventh-Day Adventists, for instance, while the Nicoyans and Sardinians are Catholics, the Ikarians are Greek Orthodox, and in Okinawa, the locals practice the Ryukyuan religion. Writing a paper for the American Journal of Lifestyle Medicine, Buettner described how all but five of the 263 Blue Zone centenarians he had interviewed were part of some kind of spiritual community. (Read more about how the Nicoyan way of life contributes to their longevity.)
Social interaction and spirituality were both found to be common among 100 year olds in places like Okinawa (Credit: Alamy)
In addition to the social connection they can provide, religious practices also offer a sense of purpose to life, and offer solace during upset, which together are thought to add between one and five years to believers’ life expectancy. That’s bad news for atheists, of course, but there may be other ways that people without faith can enjoy the same benefits. Some cities already have secular assemblies that offer time for contemplation, meditation and social support from like-minded individuals, which should, in theory, have many of the same life-enhancing effects without the belief of divine intervention. The awe we experience in nature may also have similar benefits.
Time for a brew?
Beyond these broad similarities between the Blue Zones, some of their more unique quirks can also give us some hints at the secrets of exceptional longevity.
When it comes to the specific elements of the diet, for instance, it’s interesting to note that on the Greek island of Ikaria, the population is known to drink a few cups of tea and coffee a day, and this seems to be associated with reduced cardiovascular disease in the region. The finding would seem to fit with longitudinal studies from elsewhere showing that drinking a few cups of these hot drinks a day can reduce the risk of problems like cardiovascular disease. This may be due to the fact they contain many micronutrients, such as magnesium, potassium, niacin and vitamin E, that act as antioxidants, mopping up toxic free radicals that may be behind many diseases.
Greek coffee – made by boiling a fine grind in a tall narrow pot – is thought to be especially good for the body since it releases polyphenols, known as chlorogenic acids, which reduce inflammation throughout the body. Inflammation contributes to many age-related diseases, such as promoting the growth of plaques in your arteries that lead to heart attacks and strokes, so the regular consumption of an anti-inflammatory polyphenols like the chlorogenic acids could reduce that damage.
They don’t even eat as much fish as you might expect for people living on an island – Christina Chrysohoou
These drinks are also associated with a lower risk of type II diabetes. Through various pathways, compounds that have anti-inflammatory and antioxidant properties – such as chlorogenic acids – appear to stabilise our blood sugar levels, by regulating our cells’ energy uptake and preventing them from developing insulin resistance – a precursor to diabetes. “It promotes the beneficial metabolism of glucose,” says Christina Chrysohoou at the University of Athens, Greece, who was a lead author on the study of cardiovascular disease in Ikaria.
Caffeinated drinks certainly aren’t a guaranteed elixir of life. But combined with a moderate, low-calorie diet, they may contribute to a longer and healthier existence. Like the food in Okinawa and Sardinia, the diet in Ikaria is notably low in meat and high in fresh fruit and vegetables. “They don’t even eat as much fish as you might expect for people living on an island,” says Chrysohoou.
Along similar lines, the exceptional longevity of Okinawa’s residents has generated lots of interest in two of its most common ingredients: the sweet potato and the bitter melon – that may have life-extending properties.
While rice is the staple carbohydrate for most of Japan, the sweet potato has long been the most common carb on Okinawa since it was first introduced in the 1600s. Unlike foods such as white bread, it has a low glycaemic index, meaning that its energy is released slowly into the bloodstream. It is also dense with nutrients like vitamins A, C and E: antioxidants that can mop up damaging free radicals, and which also reduce inflammation.
The sweet potatoes’ potassium content helps to reduce blood pressure. The tuber is also high in fibre (which is essential for a healthy gut microbiome) and low in cholesterol and saturated fat, all of which should reduce the risk of chronic disease. (Read more about how a high-carb diet may explain why Okinawans live so long.)
Greek coffee is thought to be particularly good for human health due to the anti-inflammatory compounds it contains (Credit: Alamy)
The bitter melon, meanwhile, looks a bit like a knobbly cucumber, with a taste a little like black tea. It is used in a variety of dishes – from salads and tempura to juice drinks. Like the Greek coffee drunk in Ikaria, it contains compounds that may stabilise glucose uptake and metabolism, reducing the risk of insulin resistance and type II diabetes.
There may be many more examples in years to come. Nutrient-dense marine organisms like seaweed, algae and kelp – all of which are consumed in Okinawa – are also attracting increasing interest for their potential to stave off age-related diseases, for instance.
A lifegiving landscape
Less researched, but equally tantalising, is the possibility that the very place where these people live may hold some clues to their exceptional longevity.
The Sardinian Blue Zone, for example, lies in incredibly mountainous, and breath-takingly beautiful, regions of the island – often called the “Selvaggio Blu” (Blue Wild) to describe the rugged terrain sweeping straight from the coast. Most of the centenarians living in Sardinia were farm workers, leading Pes and Poulain to speculate that the steep slopes increased the physical activity of their already demanding day-to-day lives. They were athletes thanks to the natural landscape and a traditional way of life.
Across the Aegean, Chrysohoou has been intrigued by the presence of low but significant levels of radioactivity on the Blue Zone in Ikaria. The island is essentially divided into two geologically distinct zones: the east, formed of sedimentary metamorphic rock, and the west, which lies on a bed of granite that leaks radioactive radon into its famous springs.
Amazingly, the longevity of the population appears to be highest in those slightly radioactive regions, while the people in the east have slightly lower lifespans. (Those springs in the west of the island are even said to produce “immortal water” by locals.) This could be a mere coincidence but Chrysohoou points to research in the US, which have also found this puzzling correlation between low levels of environmental radiation and longevity.
Amazingly, the longevity of the population appears to be highest in those slightly radioactive regions
“The Rocky Mountain States, for example, have a lower prevalence of cancer death compared to the Gulf States,” says Chrysohoou – yet the background radiation in Idaho, Colorado and New Mexico is around three times as high as the natural background radiation in Louisiana, Mississippi and Alabama. A few animal studies have also found that a very low dose of radiation can induce an anti-inflammatory response and DNA repair – possibly in the same way that the small but beneficial stress of caloric restriction can trigger protective mechanisms within cells.
For the time being, the finding remains a curiosity. Many more studies would have to confirm that these patterns cannot be explained by other factors and their potential mechanisms; Chrysohoou certainly isn’t suggesting that radioactive drinks might be the elusive elixir of youth. “It is rather dangerous to expect that radioactivity is good for your health,” she admits.
The moderation principle
Clearly, exceptional longevity of the Blue Zones can’t be restricted to a single magic ingredient, but is the combination of many factors – some of which are shared between the regions, and some of which are unique to each individual place. While that may not be as enticing as the discovery of a miraculous anti-ageing elixir or superfood, there are nevertheless many ways we could learn from these discoveries.
Eating moderately with plenty of fruit and vegetables, exercising plenty, drinking coffee and tea, and finding space for spiritual solace (whether that’s church or a long mountain walk) – these are things that we can all build into our daily lives.