Wisdom is difficult to define. There are those we know to be wise – Gandalf, Obi-Wan Kenobi, Kermit the Frog – but Because they are wise it is more difficult to say. There is no single, comprehensive definition of wisdom, some scientists argue. But what they know is that a state of being has an inverse relationship with wisdom: loneliness.
Tanya Nguyen is an assistant professor of psychiatry at the University of California, San Diego. She is very interested in the evidence to suggest that people who are considered wiser are less likely to feel alone, and those who are more lonely are less wise. She also studies the gut-brain axis and how the relationship between the gut microbiome and the brain influences healthy aging.
Nguyen’s new study combines these two interests, finding that wisdom and loneliness influence the gut – or are influenced by the gut. Or maybe both. Either way, there is a connection – a behavioral and biological link ready to be explored, with the potential to inspire new treatments for the mind and body.
“We can’t know for sure right now, but my guess is that it’s probably a little bit of both,” Nguyen told me. This was a cross-sectional study, which means that it can show a connection, but it cannot predict the “directionality of the relationship”.
“We know that being alone can lead to other physiological changes in the body, so it is possible that these changes may also involve, or perhaps even be caused by, the microbiome,” she says.
“Or, conversely, maybe having a specific microbiome can change the social behaviors that lead to loneliness.”
The link between instinct and behavior
When it comes to how the gut influences the self, most of what we know comes from animals. Studies on different animal species, explains Nguyen, demonstrate that microbes can create clues that are used in social interactions and communications. Rodent studies, for example, suggest that changes in the gut microbiota can modulate emotional behaviors, including depression and anxiety.
We still don’t have equivalent research on people, but previous research has linked intestinal microbial diversity and composition to certain personality traits and psychosocial constructions. For example, a study published in March 2020 in Human Microbiome Journal found that more sociable people have a more diverse gut microbiome, while more anxious people have a less diverse gut microbiome. But most importantly, this is an observed association – not a cause and effect finding.
Study by Nguyen and his colleagues, published in March in the journal Frontiers in psychiatry, is the first to show that loneliness and wisdom are related to intestinal microbial diversity and composition.
What was discovered – The team analyzed fecal samples from 184 study participants aged 28 to 97, along with their self-reported measures of loneliness, wisdom, compassion, social support and social involvement. These fecal samples helped the team to measure microbial intestinal diversity.
They looked for alpha diversity – which is the “ecological richness” of microbial species within a person – and beta diversity, which are differences in the microbial community between people.
“… aspects of mental health and well-being are very closely connected for our physical health. ”
Overall, higher levels of wisdom, compassion, social support and involvement have been associated with more diverse intestinal microbiomes. Loneliness, in turn, was associated with a decrease in microbial diversity, especially among older adults, which is in line with previous studies that suggest that the elderly are especially vulnerable to the health consequences of loneliness.
Still, “the mechanisms by which loneliness, compassion and wisdom can be related to microbial diversity in the gut are unknown,” writes the team. Another study found a link between reduced alpha diversity and poorer physical and mental health, while low microbial diversity is also related to conditions such as major depressive disorder.
There is, the study suggests, the possibility that lonely people “may be more susceptible to developing different illnesses”, while social support, compassion and wisdom may confer “protection against the instability of the intestinal microbiome related to loneliness”.
What is the next – Can removing loneliness improve gut health and, in turn, help healthy aging? It’s possible. Wisdom can be increased through behavioral interventions. This study is a sign that it is a smart choice for general well-being.
“The most important message [of the study] is that aspects of mental health and well-being are closely linked to our physical health, ”says Nguyen.
“Even seemingly ‘confused’ concepts, such as loneliness and wisdom, can be related and perhaps even influenced by ‘tough’ biological entities. Loneliness contributes to true medical morbidity [even mortality], and the intestinal microbiome may be an important factor in this connection. “
This complex interaction between the gut and the brain, says Nguyen, has been known for centuries. Some of the first reports relating to gastrointestinal functioning and mental health date from the late 18th and early 19th centuries. But the past five years have witnessed a revival in gut brain research due to technological advances in the sequencing of microorganisms.
Next, she wants to study the gut microbiome over time in an effort to understand the chicken and egg connections here. Is the gut influencing behavior, leading to loneliness, or is loneliness influencing the gut? The answer can help experts know how they can intervene and develop “therapies to help improve mental health and aging,” says Nguyen.