It Takes Guts to Fend Off Loneliness and Achieve Wisdom

Summary: Both wisdom and loneliness appear to be influenced by microbial diversity within the gut, a new study reports.

Source: UCSD

The evolving science of wisdom rests on the idea that wisdom’s defined traits correspond to distinct regions of the brain, and that greater wisdom translates into greater happiness and life satisfaction while being less wise results in opposite, negative consequences.

Scientists have found in multiple studies that persons deemed to be wiser are less prone to feel lonely while those who are lonelier also tend to be less wise. In a new study, published in the March 25, 2021 issue of the journal Frontiers in Psychiatry, researchers at University of California San Diego School of Medicine take the connection between wisdom, loneliness and biology further, reporting that wisdom and loneliness appear to influence — and/or be influenced by — microbial diversity of the gut.

The human gut microbiota is comprised of trillions of microbes — bacteria, viruses, fungi — that reside within the digestive tract. Researchers have known for a while about the “gut-brain axis,” which is a complex network that links intestinal function to the emotional and cognitive centers of the brain.

This two-way communication system is regulated by neural activity, hormones and the immune system; alterations can result in disruptions to stress response and behaviors, said the authors, from emotional arousal to higher-order cognitive abilities, such as decision-making.

Past studies have associated gut microbiota with mental health disorders including depression, bipolar disorder and schizophrenia, as well as personality and psychological traits regarded as key, biologically based components of wisdom. Recent research has connected the gut microbiome to social behavior, including findings that people with larger social networks tend to have more diverse gut microbiotas.

The new Frontiers in Psychiatry study involved 187 participants, ages 28 to 97, who completed validated self-report-based measures of loneliness, wisdom, compassion, social support and social engagement.

The gut microbiota was analyzed using fecal samples. Microbial gut diversity was measured in two ways: alpha-diversity, referring to the ecological richness of microbial species within each individual and beta-diversity, referring to the differences in the microbial community composition between individuals.

“We found that lower levels of loneliness and higher levels of wisdom, compassion, social support and engagement were associated with greater phylogenetic richness and diversity of the gut microbiome,” said first author Tanya T. Nguyen, PhD, assistant professor of psychiatry at UC San Diego School of Medicine.

The authors said that the mechanisms that may link loneliness, compassion and wisdom with gut microbial diversity are not known, but observed that reduced microbial diversity typically represents worse physical and mental health, and is associated with a variety of diseases, including obesity, inflammatory bowel disease and major depressive disorder.

A more diverse gut microbiota may be less susceptible to invasion by outside pathogens, which could contribute to and help promote better resilience and stability of the community.

“It is possible that loneliness may result in decreased stability of the gut microbiome and, consequently, reduced resistance and resilience to stress-related disruptions, leading to downstream physiological effects, such as systemic inflammation,” the authors wrote.

“Bacterial communities with low alpha-diversity may not manifest overt disease, but they may be less than optimal for preventing disease. Thus, lonely people may be more susceptible to developing different diseases.”

This shows gut microbes
Greater diversity of gut microbes may be associated with greater wisdom or vice versa; similarly less diversity might mean higher likelihood of being lonely. Image is credited to UCSD

The relationship between loneliness and microbial diversity was particularly strong in older adults, suggesting that older adults may be especially vulnerable to health-related consequences of loneliness, which is consistent with prior research.

Conversely, the researchers said that social support, compassion and wisdom might confer protection against loneliness-related instability of the gut microbiome. Healthy, diverse gut microflora may buffer the negative effects of chronic stress or help shape social behaviors that promote either wisdom or loneliness. They noted that animal studies suggest that gut microbiota may influence social behaviors and interactions, though the hypothesis has not been tested in humans.

The complexity of the topic and study limitations, such as the absence of data about individuals’ social networks, diet and degree of objective social isolation versus subjective reports of loneliness, argue for larger, longer studies, wrote the authors.

“Loneliness may lead to changes in the gut microbiome or, reciprocally, alterations of the gut milieu may predispose an individual to become lonely,” said Dilip V. Jeste, MD, Distinguished Professor of Psychiatry and Neurosciences at UC San Diego School of Medicine and senior author of the paper. “We need to investigate much more thoroughly to better understand the phenomenon of the gut-brain axis.”

Co-authors include: Xinlian Zhang, Tsung-Chin Wu, Jinyuan Liu, Collin Le, Xin M. Tu and Rob Knight, all at UC San Diego.

About this neurobiology research news

Source: UCSD
Contact: Scott LaFee – UCSD
Image: The image is credited to UCSD

Original Research: Open access.
Association of Loneliness and Wisdom With Gut Microbial Diversity and Composition: An Exploratory Study” by Tanya T. Nguyen et al. Frontiers in Psychiatry


Association of Loneliness and Wisdom With Gut Microbial Diversity and Composition: An Exploratory Study

Loneliness and wisdom have opposite effects on health and well-being. Loneliness is a serious public health problem associated with increased morbidity and mortality. Wisdom is associated with better health and well-being. We have consistently found a strong negative correlation between loneliness and wisdom.

The present study aimed to investigate the association of loneliness and wisdom with the gut microbiome. One hundred eighty-four community-dwelling adults (28–97 years) completed validated self-report-based measures of loneliness, wisdom, compassion, social support, and social engagement. Fecal samples were collected and profiled using 16S rRNA sequencing.

Linear regression analyses, controlling for age and body mass index, revealed that lower levels of loneliness and higher levels of wisdom, compassion, social support, and social engagement were associated with greater phylogenetic richness and diversity of the gut microbiome. Partial least squares (PLS) analysis to investigate multivariate relationships extracted two composite variables.

Linear regression model predicting alpha-diversity with PLS components revealed that a linear combination of all psychosocial predictors (with negative loading for loneliness and positive loadings for all others, including wisdom, compassion, social support, and social engagement) was significantly associated with alpha-diversity. For beta-diversity, compassion and wisdom accounted for a significant proportion of variance in overall microbial community composition.

Findings may have implications for interventions to reduce loneliness and possibly its health-related adverse consequences.

Future research should explore whether increasing compassion and wisdom may improve loneliness and overall well-being as well as microbial diversity.

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  1. Jill Louise Ryan CDA,PA,I was thinking about how biota status might be linked to depression, or intellectual ability(wisdom as your study defines this).One influences the other. Yet we know that intestinal imbalances that cause unpleasant symptoms, also result in withdrawal socially. I have co-founded the Gluten Intolerance Group of North America (USA), and we verified that those inflamed tissues (GSE people were ill), led to loneliness because symptoms affect ones desire,stamina,endurance, fertility,or energy. In example, being sociable is not easily maintained, when one is suffering. When a person has GSE,they have diarrhea and bloating, leading to isolation. This is true of other bowel diseases too, maybe even Covid. I wonder if the biota affects mood, or the illness + resulting inflammation secondarily affect the balance of the microbiota, either imbalance would be depressing, leading to symptoomology that includes social distancing, because the person needs to be in the lav too often.

  2. Why does this article’s title and content imply that gut diversity is likely to cause wisdom/loneliness? The scientific article on which this article is based never says this, and only says there’s a correlation between the two.

    Correlation is not causation.  Given that widely known scientific truth, this article seems to be extremely slanted at best, or worse, to be Misinformation.  The title and this article’s main argument assert that gut diversity causes wisdom or loneliness, but there is no evidence of causation in the original paper’s study. Just because these two factors are _correlated_ does not mean that gut diversity causes wisdom/loneliness. It could very well be the reverse, that wisdom/loneliness cause gut diversity, either directly or, more likely, indirectly (or that another factor causes them both). The scientists in the original paper call this point out.

    Intuitively, it seems highly likely that if someone is lonely they have reduced social interaction, which would lead to less exposure to microbes and thus lower gut biodiversity. Similarly, it seems likely that someone who is wise has had many experiences and/or social interactions, leading to more exposure to microbes and higher gut biodiversity. That said, the original paper does point out two studies (sources 71 and 72 there) that indicate that probiotics can influence psychological positivity/stability. These do give some credence to the stance the current article takes. However, the current article never talks about the issues of correlation, causation, and possible evidence (such as those two sources) that would support its theories.

    This article feels extremely misleading and does not back up its titular argument with evidence.  For a science-based article (in a science-based journal) to be so unscientific is, at the least, disappointing, and in a larger context, a dis-service to the scientific community and the understanding of science by the lay community.

    In the future, please write more accurately/scientifically, explain scientific context (such as correlation and causation) to your readers so they can be correctly informed, and back up your claims with evidence.

  3. Retirement and nursing homes are like epicenters for problems of loneliness; most provide less than ideal diets for the residents in an effort to mitigate costs. I hope the authors will consider using the abundance of data to be had from industrialized living situations (prisons, isolated communities, etc.) in their studies. There they can have great access to the various data their current studies lack. Sadly, even hospitals fail miserably when it comes to addressing real nutrition as part of a patient’s course of treatment.

  4. Could it simply be that lonely people have less contact with people, places and things, which limits their gut microbiome?
    Though I do understand that the effects of an unbalanced gut can cause someone to drop out of social gatherings, in turn leading to loneliness.

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