A study by UCLA shows a link between gut bacteria and emotional response
There may be a connection between the compositions of the gut and the brain
Gut bacteria has also been linked to autism, Parkinson’s disease and anxiety
There may be a link between human guts and feelings, new research shows.
Gut bacteria have become a hot topic of health research in the last several years, with recent studies linking the gut to everything from autism to Parkinson’s disease to anxiety.
A new study from UCLA adds further evidence to the connection between the gut and emotional responses.
In the study a group of 40 women was divided into two groups by the composition of their gut bacteria. Researchers then measured their brain activity for emotional responses to images.
The study found that the brains of women with different bacterial profiles reacted differently to the stimuli.
A new study from UCLA adds further evidence to the connection between the gut and emotional responses (file image)
EXPLAINED: YOUR GUT BACTERIA – AND WHAT THEY DO FOR YOU
The human gut has more bacteria than any other part of the body, both in number and diversity.
There are four major types of gut bacteria: Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria.
Firmicutes play a role in energy re-absorption, and may be linked to diabetes and obesity.
Bacteroidetes account for 30 percent of all gut bacteria, and are important to our ability to digest and use energy from carbohydrates and sugars.
Acinobacteria produce bioactive metabolites, which we use in medicines like antibacterials.
Proteobacteria are a category of bacteria that include diseases like chlamydia, but exist in healthy guts.
The majority – 33 – of the random sample of women had more of a kind of gut bacteria called Bacteroides, while the other seven had more Prevotella.
Women with greater amounts of Bacteroides tended to have more dense gray matter in their frontal cortices and insula and a higher volume of brain matter in the hippocampus. These parts of the brain are involved in complex information and memory processing, respectively.
The women with more Prevotella, on the other hand, had less dense brain matter in these areas and more ‘connections’, according to the study, between the parts of their brains more responsible for emotional, sensory and attention processes.
Earlier research has linked gut microbiota and emotions in other animals, such as rodents, and some studies have found links between the human gut and our feelings, but there is much less research in this area, and there have been no causal findings.
Studies of mice have shown that if they are not exposed to normal bacteria as they develop and grow from birth, they tend to be less anxious. When these same mice were introduced to microbiota taken from humans with high anxiety levels, the mice became more anxious too.
This most recent study, led by Dr Kirsten Tillisch, suggests that different intestinal bacteria are linked to anxiety in humans as well.
The researchers showed the subjects images of people, activities and objects that they might have an emotional response to.
The second group of women, the Prevotellas, reported higher levels of anxiety and distress when they were shown negative images than the group with more Bactroides.
This study is one in a growing body of data on gut bacteria and physical and mental health.
Pharmaceutical and wellness companies have noticed, and have been marketing probiotics said to improve general physical and mental health for years already, as we reported in January of 2014.
It’s unclear, though, if the gut is influencing the brain and its development, or if the brain is influencing the gut.
Researchers warn that it is hard to draw conclusions at this point, as this is still a young field of research and most of the large-scale studies are ongoing.
Other research has tried to establish a connection between ‘microbial communities,’ or microbiotic profiles and geography.
But a 2016 Brown University study found that that there was no consistent profile once a wide sample was taken, and the prevalence of Bacteroides over Prevotella or visa versa was probably determined more by diet, lifestyle and health than it was by location.
The study reexamined the division of Western and non-Western gut bacteria profiles, but its conclusions suggested that digestive flora are determined by nurture than by nature.
An ongoing study at the University of North Carolina Chapel Hill, however, began studying newborns in 2014, analyzing fecal samples for their gut bacteria while monitoring their brain development.
Its results could shed light on whether Dr Tillisch’s findings are determined by the diets or development of its subjects, and how either of these impacts their emotional response.
One study in Canada examined the residents of Walkertown after its water supply was contaminated by bacteria, including E. Coli.
Unsurprisingly, about 2,300 people developed stomach infections. But researchers also noticed that those exposed to the tainted water were becoming more prone to anxiety, depression and other mental illnesses.
Gut bacteria are not only important to digestion; about 95 percent of serotonin, the neurochemical, that helps to balance mood, is produced in the gut.
Source: Daily Mail
