A long life span free from diseases and disability, the so-called healthy aging, has been a matter of prime interest to humanity. It is widely held that the life expectancy is a function of interplay between various genetic and environmental factors. There is scientific evidence to support the fact that only about 20% of the average lifespan is governed by the genetic milieu and rest 80% by the potentially modifiable lifestyle factors (1).  Therefore the specific characteristics of natural or cultural environment that may facilitate the emergence of extreme longevity have been extensively explored in recent years.

In the pursuit of finding the secrets of longevity, a few isolated regions across the globe have been identified as the areas of happiness and longevity – “The Blue Zones (BZ)”.  The concept of “blue zone” came into existence on the basis of demographic work of Gianni Pes and Michel Poulain (2); which identified Sardinia as the region of the world with the highest concentration of male centenarians. Later on, the term was featured on Dan Buettner's November 2005 National Geographic magazine cover story, "The Secrets of a Long Life". Five "Blue Zones" have been identified, namely, Okinawa (Japan), Sardinia (Italy), Nicoya (Costa Rica), Icaria (Greece), and Loma Linda, California (3). The advantages of the BZ concept are evident as potential longevity determinants may be found among common traits of the concerned population and characteristicsof the shared lifestyle and environment.

Blue Zones have uncovered nine evidence-based common denominators among the world’s centenarians that are believed to slow this aging process:

(i) Move naturally – they live in close co-ordination with nature and environments by intertwining their daily chores with natural resources.

(ii) Purpose – the Okinawans call it Ikigai and the Nicoyans call it plan de vida; which implies “why I wake up in the morning.” Knowing your sense of purpose is worth up to seven years of extra life expectancy.

(iii) Downshift – stress could be a root cause of several chronic diseases and hence shorter life span. Blue zone people have their own innovative ways to deal with stress. Okinawans take a few moments each day to remember their ancestors; Adventists pray; Ikarians take a nap; and Sardinians do happy hour.

(iv) 80% Rule – people in the Blue Zones eat their smallest meal in the late afternoon or early evening, and then, they do not eat any more the rest of the day. An age-old Okinawan proverb says “Hara hachi bu” which meansto stop eating when the stomach is 80% full.

(v) Plant slant – people in blue zones have dietary habits focussed mainly around natural and seasonal locally grown vegetarian foods.

(vi) Wine @ 5 – people in all Blue Zones (except Adventists) believe in moderate and regular alcohol intake. The trick is to drink 1 to 2 glasses per day (preferably Sardinian Cannonau wine), with friends and/or with food.

(vii) Belong – most centenarians tend to associate themselves to some faith-based community regardless of denomination. Research shows that attending faith-based services 4 times per month will add 4 to 14 years of life expectancy.

(viii) Loved ones first – successful centenarians in the Blue Zones put their families first. They commit to a life partner (which can add up to 3 years of life expectancy) and invest in their children with time and love.

(ix) Right tribe – The world’s longest lived people chose—or were born into—social circles that supported healthy behaviours. Okinawans created moais—groups of 5 friends that committed to each other for life. The social networks of long-lived people have favourably shaped their health behaviours (4).

The Probable Factors Governing Special Attributes of Blue Zone People
The blue zones of the world identified so far lie in difficult mountain terrains and very high altitudes. Such a geographic situation results in limited opportunities of immigration, favours inbreeding, intermarriage and consanguinity, thus decreasing the variability of the genetic pool. For many years an agricultural economy, pastorizia, and livestock breeding represented the only sources of income. The inhabitants of this area maintain certain distinctive peculiar cultural and anthropological characteristics typical of the ancient traditions, which are favoured by local authorities. Accordingly, nutrition and other lifestyle habits are rather conservative and healthy (2).
The life in the mountains or on a remote island is associated with a set of tightly linked variables affecting both individual behaviour (diet, physical activity) and, more generally, the social context (habitat, economic activity, community support) and the environment (degree of pollution, quality of drinking water). Mountain environment is associated with increased land steepness which entails a constant stimulus for outdoor physical activity even by subjects of advanced age. The elevated average slope of the terrain, fairly common in mountainous areas, may imply greater energy expenditure during active life, thus resulting in improved cardio-respiratory fitness, and ultimately in better survival.

Also, absence of a true class gradient and a consequent absence of social competition and individual stress, hallmarks of the Sardinian and Greek blue zone inhabitants, might have created significantly more favourable conditions for individual health than those operating in the more competitive mainland framework (5).

Relevance of “Blue Zones” Lifestyle in Urban World
The euphoria of modern day health achievements is at an epidemiological crossroads. We are going to lose out the hard-won health benefits to modern monsters such as obesity and its associated diseases. Buettner’s study concluded that a healthy lifestyle without effort comes from an enabling environment. Trying to achieve longevity consciously does not sustain because people tend to be non-compliant with fixed regimens on long-term basis. Instead, inculcating healthy lifestyle habits has to go along with behavioral changes that do not require any conscious efforts. The secret of longevity of BZ people as per Buettnerlies in following a lifestyle that is naturally healthy. In 2009, Buettner partnered with a wellness provider to create the Blue Zones Project, which works to create sustainable environments where communities move naturally, eat fresh and healthy foods, and connect socially. His work in his first project city of Albert Lea in Minnesota added 2.9 years to people’s lives and saw health claims drop by 49%. Being “mindlessly healthy”, as he puts it, is the secret to health and happiness.

Concept of Optimizing ‘Life Radius’ for Longevity
It is evident that individuals spend about 90% of their lives within 5 miles of their home, known as the ‘Life Radius’. To engineer an environment where longevity ensues, Blue Zones worked with researchers to create a blueprint to optimize the Life Radius. Individuals can engineer their kitchen, so they eat about 100 fewer calories and engineer their home, so they burn a couple of hundred extra calories through physical activity. This is done through small changes such as putting a bowl of fruit on the counter, serving food at the stove and not on the table, using hand tools for yard work, and many more.

Creating social networks of health conscious people would encourage healthy living and create a sense of purpose of life in the community. There are 115 evidence-based design tweaks and policies that can be put in place, so that when people show up at school, work, church, stores, and restaurants they are mindlessly nudged to eat less and move more. These tweaks include things such as standing desks at work, removal of vending machines in schools, no breadbaskets at restaurants, safe walking paths, and encouraging moais. If there are 6 or more fast food restaurants within half a mile of an individual’s home, they are 40% more likely to be obese than if there are less than 3. If streets are walkable and bikeable, parks are cleaned up, and the active option is the easy option, physical activity of the entire population can rise by 30% (6).

Relevance of Concept of Blue Zones Lifestyle in Indian Context
The average life expectancy of Indian population is 70.8 years (WHO report 2019-20), which is lower than the global average of 73.4 years (7). The concept of healthy living of blue zones is worth exploring in Indian context as we are the world capital of several chronic illnesses (diabetes and cardiovascular diseases) which could be the cause of comparatively lower lifespan of our population.
 
Are Indians eating healthy to support longevity?
The dietary pattern of Indian households has been reported to be deviating from recommendations of healthy eating. An observational study comparing the food consumption patterns from various income groups, regions and sectors from 1.02 lakh households in  India, with the EAT-Lancet reference diet has reported that whole grains were contributing significantly more calories than the EAT-Lancet recommendations, whereas the consumption of fruits, vegetables, legumes, meat, fish and eggs were much lower irrespective of the socio-economic strata. Protein share was only 6–8 per cent, compared to the 29 per cent recommendation. These outcomes were independent of the socio-economic status of Indian households. An average Indian household consumes more calories from processed foods than fruits. Authors concluded that the average Indian diet is unhealthy, lacking essential food groups (8).
There are reports from nationwide observational studies suggesting that lifestyle and eating habits of Indian households are reported to be associated with elevated risk of blood glucose and cardiovascular diseases. A national-level cross-sectional survey in 2017–18 by the National NCD Monitoring Survey studied the prevalence of risk factors in 12,000 Indian adults, revealed that 32.8 percent of respondents used tobacco, 15.9 percent consumed alcohol, 41.3 per cent were not physically active, 98.4 percent consumed less than five servings of fruits and vegetables per day (9).

Therefore, increased susceptibility to chronic diseases on account of the current Indian lifestyle and eating practices could be a factor associated with reduced lifespan. The exploration of strategies for implementation of concepts of blue zones lifestyle and eating pattern is worth exploring. Eating like a Mediterranean could be an effective measure to promote disease-free increased lifespan for the Indian population. It includes more raw fruits and vegetables in salads; whole grains instead of polished rice; legumes, pulses, and beans in form of sprouts, salads, less spicy curry; healthy fats from nuts, seeds, olive oil, coconut, and avocado; along with limited intake of meat and sweets. All processed foods like refined sugar, refined wheat flour, biscuits, and instant noodles should be gradually eliminated from the daily diet (10).
The Government of India’s initiative approved by FAO to promote traditional Indian millet based diet by declaring year 2023 as ‘International Year of Millets’ may be of great significance in promoting the Mediterranean style of eating pattern in India. The millets are regarded as powerhouse various phyto-nutrients and are also rich in fibreand micronutrients. Incorporating millets in modern day Indian diets could be an effective strategy to promote healthy eating in Indian population. This in combination with lifestyle changes as suggested in blue zones lifestyle might prove very effective in reducing the burden of chronic diseases in India and in turn would lead to an increase in longevity. The value of millets is evident in their relevance to the Sustainable Development Goals (SDGs) of food security, nutrition and poverty eradication. Brimming with potential, millets can act as a vital cog in the country’s sustainable development wheel if backed by policies that promote their production, incentivize farmers and strengthen market linkages.

References
1.    Herskind AM, McGue M, Holm NV, Sorensen TIA, Harvlad B, Vaupel JW. The heritability of human longevity: a population-based study of 2,872 Danish twin pairs born 1870–1900. Hum Genet.1996;96:319-323
2.    Michel Poulain, Giovanni Pes, Claude Grasland, Ciriaco Carru, Luigi Ferrucci, et al.. Identification of a geographic area characterized by extreme longevity in the Sardinia island: the AKEA study. Experimental Gerontology, Elsevier, 2004, 39 (9), pp.1423–1429
3.    Poulain, M., G. M. Pes, C. Grasland, C. Carru, L. Ferrucci, G. Baggio, C. Franceschi, and L. Deiana. 2004. “Identification of a Geographic Area Characterized by Extreme Longevity in the Sardinia Island: The AKEA Study”. Experimental Gerontology 39 (9): 1423–1429
4.    Buettner D, Skemp S. Blue Zones: Lessons From the World's Longest Lived. Am J Lifestyle Med. 2016;10(5):318–321
5.    Poulain, Michel, et al. “The Blue Zones: Areas of Exceptional Longevity around the World.” Vienna Yearbook of Population Research, vol. 11, 2013, pp. 87–108
6.    Buettner D, Skemp S. Blue Zones: Lessons From the World's Longest Lived. Am J Lifestyle Med. 2016;10(5):318–321
7.    https://www.who.int/data/gho/data/themes/mortality-and-global-health-estimates/ghe-life-expectancy-and-healthy-life-expectancy
8.    Manika Sharma, Avinash Kishore, Devesh Roy and Kuhu Joshi, A comparison of the Indian diet with the EAT-Lancet reference diet, BMC Public Health (2020) 20:812
9.    Mathur P, Kulothungan V, Leburu S, Krishnan A, Chaturvedi HK, Salve HR, et al. (2021) National noncommunicable disease monitoring survey (NNMS) in India: Estimating risk factor prevalence in adult population. PLoS ONE 16(3): e0246712
10.    Subhasree Ray, 20 August, 2021,https://theprint.in/opinion/how-can-indians-live-longer-we-need-the-blue-zone-diet/718698/

About the Authors:
Rekha Ramot, PhD (Nutritional Endocrinology), AIIMS; Life member of IDA (Indian Dietetic Association)
She has published several research articles in peer-reviewed journals, written a book chapter, and presented papers at several national and international conferences. She is the recipient of ‘ECTS East-Meets-West Research Award’ and 'AR SETH AWARD'.
Email: rekha.gem@gmail.com

Dr. Raj Bhandari, MD (Paed), Member of National Technical Board of Nutrition and Task Force for Millets Promotion, Government of India
He is working as technical advisor to the women and child development ministry in Telangana, Madhya Pradesh and Rajasthan. He is also represented on the board of several organisations like CFNS, ILBS, ICAR - IIMR, FLAIR etc. He has served in cross-sectional fields, to emerge as a thought leader in the field of public health and nutrition.
Email: rajbhandari53@gmail.com