The gut microbiome is a unique community of microorganisms such as bacteria, parasites and viruses that co-exist in the intestinal tract and is gaining increasing attention as an important role in both mental and physical health. Everyone’s microbiome is unique and influenced by what we eat, our behavior, and our environment.
While the findings are modest, they add to a growing body of research in the nascent field of nutritional psychiatry, drawing renewed attention to the relationship between the brain and the gut, especially in the aftermath of trauma and adversity. there is a possibility. Previous studies have established the importance of gut microbes that can influence various conditions such as depression, anxiety, and heart disease.
The study, published last month in the journal PNAS, is based on a large longitudinal study examining maternal experiences of childhood abuse and anxiety during pregnancy. Researchers who analyzed the data found an association between maternal stress and children’s gut microbiome status at age two. The researchers also tracked stress in children during early childhood and found a correlation between certain inflammation-related gut bacteria in toddlers as young as two years old and increased mental health problems at four years old. It pointed out.
“Adversity tends to lurk in the mind,” says Bridget Callahan, lead author of the study and assistant professor of psychology at UCLA. “And this is another way we think adversity affects an individual’s physiology.”
A novel perspective on intergenerational trauma
Research into how trauma and adversity are passed on from generation to generation is not new. Ongoing research is investigating the transgenerational transmission of trauma through a variety of means, including genetics, learning behavior, and even the collective experience of the population.
One of the new aspects of the current study, Professor Callahan said, is that her team investigated the effects of adversity experienced by women, in some cases before their children were conceived.
Studies in rodents have documented the effects of maternal stress on offspring’s microbiome, but “how the scars of preconception adversity are inherited and affect the human microbiome remains unclear.” No one has looked into it,” Callahan added.
The new study raises intriguing questions about the link between stress and the microbiome, but has no definitive answer, and some experts are skeptical of the findings.
For example, researchers have not determined that the transmission of trauma passes directly from the mother’s microbiome to the child’s microbiome. That route is possible because infants acquire their first gut bacteria from breast milk through the mother’s birth canal, Callahan said. However, infection is much more likely to occur through other biological or behavioral routes.
“I think the most likely scenario is that the effects of adversity on mothers’ mental and physical health, and perhaps parenting behavior, are affecting the next generation,” she said. “And that stress is affecting the next generation’s microbiome.”
A Look at Three ‘Adversity Exposures’
The study analyzed data collected as part of a study known as ‘GUSTO’ (Growing up in Singapore for Healthy Outcomes) of 450 mother-child pairs living in Singapore.
Children’s fecal samples were collected at age 2 and analyzed to determine the composition of the child’s microbiome. Callahan and her colleagues focused on three different “adversity-challenged” moments experienced by both mothers and children.
- Childhood maternal abuse, including physical, sexual or other abuse or neglect.
- Anxiety of pregnant mom.
- Early exposure of children to stressful life events, such as divorce or the death of a grandparent.
As part of the study, researchers also had access to information on the social and emotional health of children aged 2 and 4, including sleep disturbances, social difficulties, anxiety, depression, and aggressive or antisocial behavior. tracked down the issue.
The researchers reported finding “clear differences in gut microbiome profiles associated with exposure to each adversity.” In other words, all children of abused or neglected mothers had similar patterns of microbes. Children who experienced anxiety in utero had different microbial signatures, similar to the microbiomes of children who experienced stressful events.
How stress ‘changes the balance’ of gut bacteria
Christopher Rowley, a professor at the University of Colorado Boulder who studies how stress affects the gut microbiome and overall health, said the new study was “groundbreaking in several important ways. significant progress,” he said, including a better understanding of intergenerational effects, prenatal effects, and the effects of stress. Early postnatal adversity in the child’s gut microbiome. The study also suggests that certain types of bacteria are associated with social and emotional development in young children.
Dr. Lowry said the study builds on previous research that maternal and childhood stress can “shift” the gut microbial balance from anti-inflammatory to inflammation-associated. said that it is a supplement to the
He said the finding that adversity in the first two years of life is associated with reduced diversity in children’s gut microbiota is important. High diversity is a key feature of a healthy gut microbiome, and the study suggests that “stress exposure reliably reduces gut microbiome diversity throughout life.” said he.
How Different Gut Microbes Affect Children’s Health
Specifically, in this study, microbes Clostridium in the strict senseAn inefficient producer of an important anti-inflammatory compound called butyrate was more abundant among children whose mothers had stronger preconceived adversities. and a more efficient butyrate producer, Ruminococcusamong these children there were not so many.
Maternal prenatal stress and childhood stressful events in children were associated with increased microbial levels fine goldia and Streptococcuswhich is thought to be involved in inflammation and has reduced abundance of anti-inflammatory associated microbes. Parabacteroides and intestinal bacteriathe researchers report.
When researchers observed the children’s behavior and mental health, they found that their emotional levels were low. intestinal bacteria At 2 years of age, it was associated with more anxiety and depression than at 4 years of age.few Coprobacillus, Lachnospiraceae UCG-008 and Faecalibacterium At age 2, it was associated with more sleep problems than at age 4. Beironella and Wet At age 2, she was having more sleep problems than at age 4.
Skepticism about survey results
Curtis Huttenhower, professor of computational biology and bioinformatics at Harvard’s TH Chan School of Public Health, said the study touches on “several important and provocative topics” related to the microbiome. He said he felt the study was limited in many respects. reason.
He noted that the study did not “establish a means” for mothers to transmit the effects of adversity to their children’s microbiomes. He also noted that mothers have a relatively small impact on the child’s microbiome, with infants acquiring most of their microbes early in life from many other sources, including fathers, other family members and the general environment around them. also mentioned to do
The study primarily examined “very abstracted, high-level information” from the microbiome, he wrote in an email. “Most of the microbes that are mentioned individually actually represent very diverse groups of multiple organisms and cannot be accurately boiled down to simple behaviors,” he said.
Professor Callahan agreed that because the study relies on genus-level microbiome data, our knowledge of the functions and effects of specific bacteria is limited. Still, she believes that the microbes pointed to in the study play a role in inflammation and immune responses, and that these changes in microbe types and abundance could help adversity and trauma affect children’s social, emotional, and mental well-being. It could be one way to influence, he added. .
This study is a retrospective analysis showing only correlations and has other limitations. Much of the data is based on mothers’ and children’s early childhood experiences and can be unreliable. This study focused only on mothers and did not investigate the influence of fathers on the composition of the offspring’s microbiome. Because the participants were all Chinese, Indian, and Malaysian, the findings do not apply to other groups, as different cultures have their own diets and coping strategies that shape their microbiomes. there is a possibility.
Jotam Suez, an assistant professor at the Johns Hopkins Bloomberg School of Public Health who studies the microbiome and its role in human health and disease, said the findings were “interesting” but should be interpreted “with caution.” said there is. He added that correlations and effect sizes are weak.
“Although changes in the microbiome can affect a child’s well-being and mental health, there is no supporting data in this paper,” Suez said in an email.
Still, it’s undeniable that a healthy gut microbiome leads to better overall health. As such, the results of this study could help direct health care providers and public health advocates to tailor more microbiome-specific interventions, such as nutrition, probiotics and prebiotics. Mr Callahan said.
“There are things that can be done at the societal level, such as access to nutritious foods that are known to have a positive impact on the microbiome,” Callahan said. “If these changes can also address the effects of intergenerational adversity, that would be very powerful.”
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