What Do Social Connectedness and the Mediterranean Diet Have in Common?


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The earliest publications by Ancel Keys about the health benefits of the Mediterranean diet have emphasized the importance of the close social interactions of people living on the island of Crete in Greece, as well as the health benefits of dietary habits.

Keys described the Mediterranean diet as consumed by people in post WWII Crete in this way: “… homemade minestrone, pasta of all varieties, with tomato sauce and a sprinkling of Parmesan, only occasionally enriched with a few pieces of meat or served with a small fish of the place … beans and macaroni …, so much bread, never removed from the oven more than a few hours before being eaten, and nothing with which spread it, lots of fresh vegetables sprinkled with olive oil, a small portion of meat or fish maybe a couple of times a week and always fresh fruit for dessert.”

While specific ingredients of the Mediterranean diet, like olive oil, fresh fruit, vegetables, and fish have received a lot of attention in terms of the wide-ranging health-promoting effects of dietary fiber, plant-based fats, polyphenols and minimal consumption of red meat, the importance of the social aspect of this dietary pattern has received much less attention.

Keys and many authors, including The Blue Zones author, Dan Buettner, write about the benefits of the Mediterranean diet with regard to longevity, and have emphasized the essential role of close social interactions between people living around the Mediterranean region. I have experienced this social connectedness around food first hand in my visits to Italy, and have often wondered if this non-dietary component of the Mediterranean food culture could outweigh the negative health effects of dramatic changes in lifestyle, including the increased consumption of red and processed meat in today’s Italy compared to the dietary pattern that Keys described in Crete in the 50s. I still have vivid memories of a recent visit to Parma, the origin of Parmesan cheese and Parma ham (prosciutto). While it was nearly impossible to find foods on the menu of restaurants that I would have called typical traditional, largely plant based Mediterranean dishes (e.g. without ham, cheese and lots of pasta), the bustling interactions between friends and family members enjoying their dinner in the many outdoor restaurant or walking around town until late into the night was different from anything I have ever experienced in the United States. And surprisingly, when I compared the life expectancy in different regions of Italy with very different dietary patterns, there doesn’t seem to be a significant difference between the Emilia Romana region of Parma and coastal regions with high fish consumption, suggesting some factors other than dietary ingredients at play..

So how important is social connectedness for the health benefits described for the Mediterranean diet, and for healthy aging, and what are the consequences of social isolation and often associated loneliness? As a matter of fact, there is a lot of science addressing this topic. In a recent interview with Dr. Wayne Jonas, he gave me the following surprising answer:

“For example, the longest study on healthy longevity ever done, gone out of Harvard, still going on, when they looked at all the factors that contributed to remaining healthy and living a long time, the biggest factor was social connections. Deep social, satisfactory connection. The second biggest factor was meaningful activity. …Those were the two biggest factors. Those were bigger than whether you smoked, whether you exercised, even what your diet was like. Not that those lifestyle factors were not important, but they weren’t necessarily the most important”.

I looked up the Harvard Study of Adult Development that Dr. Jonas had mentioned in our interview. This long-running study was started in 1938 with the goal to identify the factors which make people flourish, mentally, physically and spiritually. The co-leaders of the study, Harvard professors Drs. Robert Waldinger and Marc Schultz discussed the results and implications of the study results in a fascinating book, The Good Life: Lessons From the World’s Longest Scientific Study of Happiness, an excerpt from which was published in the January 19, 2023 issue of the Atlantic magazine. Here is a quote from their article: “Loneliness has a physical effect on the body… It can render people more sensitive to pain, suppress their immune system, diminish brain function, and disrupt sleep, which in turn can make an already lonely person even more tired and irritable.”

Research has found that for older adults, loneliness is far more dangerous than obesity. Ongoing loneliness raises a person’s odds of death by 26 percent in any given year. A study in the U.K., the Environmental Risk (E-Risk) Longitudinal Twin Study, recently reported on the connections between loneliness and poorer health and self-care in young adults. This ongoing study includes more than 2,200 people born in England and Wales in 1994 and 1995. When they were 18, the researchers asked them how lonely they were. Those who reported being lonelier had a greater chance of facing mental-health issues, partaking in unsafe physical-health behaviors, and coping with stress in negative ways. Add to this the fact that a tide of loneliness is flooding through modern societies, and we have a serious problem. Recent stats should make us take notice.”

As a matter of fact, the public recently has taken notice of this hidden epidemic. The topic of loneliness and social isolation has recently made the news headlines in the US when United States Surgeon General, Dr. Vivek Murthy, released a new Surgeon General Advisory calling attention to the public health crisis of loneliness, isolation, and lack of connection in the US.

As quoted from Murthy’s report: “Even before the onset of the COVID-19 pandemic, approximately half of U.S. adults reported experiencing measurable levels of loneliness. Disconnection fundamentally affects our mental, physical, and societal health. In fact, loneliness and isolation increase the risk for individuals to develop mental health challenges in their lives, and lacking connection can increase the risk for premature death to levels comparable to smoking daily.”

In a study conducted online that sampled 55,000 respondents from across the world, one out of every three people of all ages reported that they often feel lonely. Among these, the loneliest group was 16-to-24-year-olds, 40 percent of whom reported feeling lonely “often or very often.” …In Japan, 32 percent of adults expected to feel lonely most of the time during 2020. In the United States, a 2019 study suggested that three out of four adults felt moderate to high levels of loneliness.”

According to this report, “The physical health consequences of poor or insufficient connection include a 29% increased risk of heart disease, a 32% increased risk of stroke, and a 50% increased risk of developing dementia for older adults. Additionally, lacking social connection increases risk of premature death by more than 60%. Given the close interactions between our emotions, the immune system and the gut microbiome, it is not surprising that the same diseases which make up the chronic non-contagious disease epidemic are amongst the negative health outcomes of both the lack of social connections and an unhealthy diet.

As explained in detail in my forthcoming The Mind-Gut-Immune Connection, the negative influences of chronic psychosocial stress (generated by loneliness and social isolation) and of chronic dietary stress (in form of the Standard American Diet) interact to alter the gut microbiome leading to systemic immune activation.

In addition to our physical health, loneliness and isolation contribute substantially to mental health challenges. In adults, the risk of developing depression among people who report feeling lonely often is more than double that of people who rarely or never feel lonely. Loneliness and social isolation in childhood increase the risk of depression and anxiety both immediately and well into the future. And with more than one in five adults and more than one in three young adults living with a mental illness in the U.S., addressing loneliness and isolation is critical in order to fully address the mental health crisis in America.”

Murthy’s report continues: “Social connection is beneficial for individual health and also improves the resilience of our communities. Evidence shows that increased connection can help reduce the risk of serious health conditions such as heart disease, stroke, dementia, and depression. Communities where residents are more connected with one another fare better on several measures of population health, community safety, community resilience when natural disasters strike, prosperity, and civic engagement.”

Returning to the Mediterranean diet, the lifestyle associated with this diet and practiced in countries around the Mediterranean would seem to be an effective way to counteract both the widespread social isolation and the detrimental metabolic effects of the Standard American Diet. Eating a home-delivered pizza or pasta alone while watching TV, eating your caprese sandwich while driving to work, or while listening to a presentation at work, will deprive you of the aspect of social connectedness traditionally associated with the Mediterranean diet.

The Surgeon General’s Advisory lays out a framework for the United States to establish a National Strategy to Advance Social Connection. However, until such policies change the national social infrastructure, individuals should become aware of the importance to not only eat healthy food, but also to work actively to maintain family ties, regular relationship with friends, and use food as a social glue to bring us closer together.

Emeran Mayer, MD is a Distinguished Research Professor in the Departments of Medicine, Physiology and Psychiatry at the David Geffen School of Medicine at UCLA, the Executive Director of the G. Oppenheimer Center for Neurobiology of Stress and Resilience and the Founding Director of the Goodman-Luskin Microbiome Center at UCLA.