If there is one popular diet that has been at the forefront of research and promoted widely to not only the general public but also within healthcare settings, it would be the Mediterranean Diet. Nearly several decades have gone by since the interest of this dietary pattern began, and within this time span there has been great evidence of its efficacy in reducing cardiovascular disease and promoting longevity. The foundation of this particular diet has an emphasis on increased daily consumption of vegetables, whole grains, and fruits; while consuming moderate amounts of dairy and limiting the intake of red meat.1
Although this dietary pattern is commonly associated with countries bordering the Mediterranean Sea, we also see this pattern -to an extent- amongst those living in other “Blue Zone” areas, such as certain parts of Japan, Costa Rica, and even here in the United States. Blue Zones® (BZ) is a trademarked term for the collection of five distinct areas, Okinawa, Japan; Sardinia, Italy; Nicoya, Costa Rica; Ikaria, Greece, and Loma Linda, California.2 Through the years, those living within the BZ have been extensively studied for their lifestyle patterns (such as diet), social connections, biomarkers, and genetic variations as important factors towards the attainment of remarkable-age also referred to as ‘supercentenarian’ status.
Two years ago, a pre-print (still under peer-review) of S.J. Newman’s study titled “Supercentenarians and remarkable age records exhibit patterns indicative of clerical errors and pension fraud” was released. Within the study, Newman brings to light current evidence that a potential role of errors and operator biases could have been overlooked in previous work.3 His findings showed that illiteracy, high crime rates, poverty, shorter average lifespans, and the absence of birth certificates were included within the data that was used as a predicated factor towards supercentenarian status.3
In this study, Newman’s method of research involved obtaining supercentenarian tables from the Gerontology Research Group that showed the number and birthplace of supercentenarians, those who have attained 110 years of age, in which he had split into subnational units for birth locations.3 Exclusion criteria that were set by Newman included poor subnational resolution of countries with less than 15 total provinces and populations with incomplete subnational birthplace records; dwindling down the useable data to only 25% of the original.3
Using this data set Newman highlighted peculiar trends from the US and in Italy that raises questions as to the validity of the current body of literature on remarkable age reportings of certain populations and individuals.3 When comparing total supercentenarians with the years before and after complete birth registration was implemented in the US (circa 1904), we see a significant drop in the total number of supercentenarians; although during this time there was rapid growth in population and increased life expectancy.3 The significant drop was represented by 82% of the supercentenarian records from the US that happened to predate the state-wide birth certification.3 This data was also reflected when adjusting for total population size per state, as shown in Figure 1.
Figure 1. Number and per capita rate of attaining supercentenarian status across US states, relative to the introduction of complete-area birth registration.
Note. Image adapted from ‘Supercentenarian and remarkable age records exhibit patterns indicative of clerical errors and pension fraud’ by S.J. Newman, pg 7, 2019.
From the years 1880 to 1900, which was the core period in which supercentenarians were surveyed, the population in the US had increased by 150% and the average life expectancy by roughly 20%.3 With such a drastic increase, it would be speculated that there should be a proportional increase in the total number of supercentenarians per capita, but the data showed the complete opposite. With the transition to state-wide birth registration, there was an 80% reduction in the total number of supercentenarians statewide, and a decrease of 69% per capita.3 This raises the question of the validity of those that claimed to be supercentenarians before the complete issuance of birth certificates.
Italy had introduced birth certificates well before the onset of records being kept of supercentenarians and its predictor in the attainment of remarkable age was actually correlated with a short average lifespan.3 When comparing the probability of survival to age 55 with the probability of survival to ages 95, 100, 105, and 110, we see an inverse relation starting after 95 years of age, as shown in figure 2.
Figure 2. Relationship between mid-life and late-life survival across Italian provinces. Note. Image adapted from ‘Supercentenarian and remarkable age records exhibit patterns indicative of clerical errors and pension fraud’ by S.J. Newman, pg 14, 2019.
Within this study, Newman had reported trends of remarkable ages coinciding with a higher prevalence of counter-indicators of health and longevity across many populations and individuals, such as seen with data sets from Japan, France, Costa Rica, as well as here in the US.3
Much of this data is not to negate the fact that the lifestyle and characteristics of those living within the BZ have a positive correlation of health and longevity, but to raise questions as to the validity of the current recorded ‘supercentenarians’ data and to what extent of longevity may be achievable with said BZ lifestyles. With the BZ lifestyle in question, what does that say about the dietary patterns they have and what are the implications towards health in contrast to other dietary patterns in countries outside of the BZ’s? Further research will be necessary to develop a better insight into the relation towards remarkable-age attaintment and its declining trend after the introduction of state-wide birth certificate in the US, as well as the inversed relation between the probability of survival to age 55 and the probability of survival beyond the age of 95 in Italy, as shown in Figure 2.
In conclusion, it is indeed an interesting study that pointed out some conflicting nuances involving a lifestyle and dietary approach that is highly regarded in not only media but in healthcare as a popular dietary intervention. It’s only a matter of time until there has been enough peer-review for this study to be further scrutinized and until then we must ask ourselves, is the Mediterranean diet and the Blue Zone lifestyle that it falls under truly the most optimal for longevity?
References:
- Mediterranean diet for heart health. Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/mediterranean-diet/art-20047801. Published June 21, 2019. Accessed March 27, 2021.
- History of Blue Zones. Blue Zones. https://www.bluezones.com/about/history/. Published August 14, 2020. Accessed March 28, 2021.
- Newman SJ. Supercentenarian and remarkable age records exhibit patterns indicative of clerical errors and pension fraud. 2019. doi:10.1101/704080.
Feature image: Created by Doreen Rodo per information in #2 above; April 11, 2021
