The argument that communities with exceptional longevity (Blue Zones) achieve their exceptional health status due to plant-based eating is flawed. Likely, the longevity effect is primarily to be ascribed to the communities’ healthy lifestyles and functional social networks. Moreover, reporting errors, dietary mischaracterizations, and skewed interpretations make the argument highly problematic. The so-called 'traditional' Okinawan diet with low protein intake may as well be the result of post-war starvation, whereas historical data show a significant consumption of pork and other animal products in Okinawa. Dairy and moderate meat intake may even be independently associated with improved rather than detrimental health outcomes in these Blue Zones. Moreover, global studies have found associations between meat intake and life expectancy in various societies.
This article discusses the following topics related to Blue Zones:
- Blue Zones: what are they and why is the concept problematic?
- The misrepresented case of the Okinawa diet
- Animal source foods are an important part of Blue Zone diets
Blue zones: what are they and why is the concept problematic?
'Blue Zones' represent communities with exceptional longevity, which are frequently referred to in support of plant-based eating and the restriction of animal source foods. Identified in places like Ikaria, Okinawa, the Ogliastra Region, Loma Linda, and the Nicoya Peninsula. The Blue Zones concept was coined in 2005 and has since been acquired by the Seventh-Day Adventist Church, to support their dietary evangelism. The concept faces criticism due to skewed interpretations and flaws in the identification of supercentenarians, including absence of birth certificates, clerical registration and age-reporting errors, and pension fraud in remote communities.
Further reading (summary of the scientific literature):
Blue Zones® - what are they?A link between 'plant-based' eating in local and traditional communities with exceptional longevity (so-called 'Blue Zones') is often advanced in support of animal source food restriction or vegetarianism [Poulain et al. 2004]. Such communities have been identified in Ikaria (Greece), Okinawa (Japan), the Ogliastra Region (Sardinia), Loma Linda (USA), and the Nicoya Peninsula (Costa Rica). The concept goes back to 2005 [Buettner 2005] and has since been acquired by the Seventh-Day Adventist Church as Blue Zones® [Adventist Health 2020], in support of their dietary evangelism for meat restriction [see elsewhere].
Why is the concept problematic?The Blue Zones argument may be flawed for various reasons. Firstly, identification of supercentenarians in Blue Zones may suffer from age-reporting errors, skewed interpretations, and registration errors and fraud in remote communities (clerical errors, absence of birth certificates, pension frauds) [Newman 2019, 2020]. Secondly, the longevity data are strongly confounded by factors beyond the diet, since members of Blue Zones lead healthy lifestyles in general and are part of functional social communities. A similar case for longevity has been made for the Mormon community [Enstrom & Breslow 2008]. Thirdly, and in contrast to what is being said, the intake of animal source foods in the Blue Zones can be substantial (see below).
Health is not necessarily optimal in the Blue Zones
The argument for meat avoidance falls apart when comparing longevity across different communities worldwide. When looking globally into 175 contemporary societies, meat intake is generally associated with a higher, not lower life expectancy [You et al. 2021]. Blue Zones may have their own set of health concerns potentially caused by the prevailing diet, such as decreased sperm quality in Loma Linda [Orzylowska et al. 2016].
The misrepresented case of the Okinawa diet
What is commonly described as the Okinawan longevity diet, having only 9% protein, does not represent a traditional diet. It refers to a snapshot of a scarcity situation, recorded in 1949 when livestock had been severely impacted by the war. Contrary to the belief that Okinawans minimized meat intake, their pork and goat consumption has been historically exceptional within Japan. The islands of Okinawa have a well-known pork food culture, with all families raising pigs, chickens, and occasionally other farm animals. Animal fats were also a significant part of cooking. Studies indicate that centenarians in Okinawa consumed twice the amount of meat compared to mainland Japanese centenarians. Apart from meat, fish and seafood were also regularly consumed in Okinawa.
Further reading (summary of the scientific literature):
The so-called 'traditional' Okinawan diet with allegedly only 9% of protein [cf. Le Couteur et al. 2016] is mainly one of starvation, as it was registered as a post-war dietary snapshot in 1949 by the American administration, after the decimating effects of the war on livestock [Fish 1988]. If anything, Okinawa was not influenced by Buddhism and levels of pork and goat consumption were historically 'exceptional among Japanese food consumption' [Shibata et al. 1992; Poulain & Naito 2005], 'the islands of Okinawa and Jeju are well known for their pork food culture' [Lee & Hyun 2018], 'all families raised pigs, and chickens and sometimes other farm animals, such as goats' [Willcox et al. 2014], and 'animal fats were mainly used for cooking' [Okuyama et al. 1996]. Studies showed that centenarians in Okinawa ate twice the amount of meat as mainland Japanese centenarians [Kagawa 1978 ; Akisaka et al. 1996]. Among other ASF regularly eaten in Okinawa are fish and seafood, especially giant clams [Sho et al. 2001, 2008 ; Claus 2017].
Animal source foods are an important part of Blue Zone diets
The Blue Zone argument disingenuously fails to acknowledge that good physical and mental health do not only correlate with the consumption of plants but also with certain animal source foods. The intake of dairy, eggs, fish, seafood, and poultry can be substantial. In some areas, like Okinawa and Sardinia, red meat is a more integral part of the diet than often assumed. In Sardinia, centenarians are predominantly found among pastoralist populations rather than cultivators.
Further reading (summary of the scientific literature):
The Blue Zone argument overlooks that not only plants but also dairy and moderate meat intake are independently associated with improved physical function in Sardinia and Costa Rica [Nieddu et al. 2020], with longevity in Okinawa [Shibata et al. 1992], and a greater animal-derived protein intake possibly with mental health in Sardinia [Ruiu et al. 2022]. In addition to what is mentioned above for Okinawa, other Blue Zones also consume considerable amounts of animal source foods. This is the case for Costa Rica, where a majority of centenarians were found eating dairy and eggs daily, and fish and poultry several times per week [Chacon et al. 2017]. In Sardinia, centenarians are particularly found in pastoralist populations, not among cultivators [Pes et al. 2011].
