New Study Suggests Link Between Gut Bacteria and Brain Cortex Thickness
Gut Bacteria’s Influence on Brain’s Cortex
In a recent study published in the Journal of Affective Disorders, researchers have found evidence suggesting that certain types of gut bacteria may have an impact on the thickness of the brain’s cortex. The study identifies specific bacteria within the Lactobacillales and Bacillales orders that show potential association with changes in brain structure.
Microbiota-Gut-Brain Axis
Scientists have long known that our gut is a host to a plethora of microorganisms that impact our overall health. Recent studies have delved into the influence of these gut microbes on the brain, leading to the concept of the microbiota-gut-brain axis. Previous research has linked changes in gut bacteria composition to a range of brain functions and disorders, including cognitive abilities and mental health conditions.
A Novel Approach: Mendelian Randomization
In an effort to provide clearer evidence, researchers at Capital Medical University in Beijing employed a technique called Mendelian randomization. By using genetic data, this technique can help infer causal relationships between gut bacteria and health outcomes. The study examined genes associated with certain gut bacteria and their impact on the thickness of different brain regions. The participants, primarily of European descent, numbered over 51,000.
Statistically Significant Associations
The researchers discovered a statistically significant association between the abundance of Bacillales and Lactobacillales and the thickness of the cerebral cortex. This association remained consistent across global measures of cortical thickness, particularly in brain regions crucial for cognitive and sensory functions.
Brain Regions Affected
The increase in cortical thickness was particularly notable in brain regions such as the fusiform, insula, rostral anterior cingulate, and supramarginal areas for Bacillales. Similarly, Lactobacillales showed a similar impact, specifically thickening the fusiform and supramarginal regions. These regions play significant roles in processes like visual processing, emotional regulation, sensory perception, and cognitive control.
Possible Mechanisms
The researchers postulate that the influence of gut microbiota on brain structure may be attributed to their impact on metabolic functions in the liver. Alterations in the synthesis and breakdown of fatty acids, influenced by gut bacteria, can impact neuronal activity when they cross the blood-brain barrier. Additionally, gut microbes produce essential metabolites and hormones crucial for the gut-brain signaling system.
Limitations and Future Directions
Despite the innovative approach of the study, certain limitations should be acknowledged. The findings are based on genetic data that estimate bacterial levels rather than direct measurements, potentially limiting their ability to capture the dynamic nature of gut microbiota. Additionally, the study primarily involved participants of European descent, and further research is necessary to generalize the results to other ethnic groups.
However, the study’s findings establish the potential of the microbiota-gut-brain axis as a target for therapeutic interventions in neurological and psychiatric disorders. The researchers suggest further investigations with diverse populations and the direct measurement of gut microbiota to corroborate these findings. They also recommend exploring the underlying mechanisms through which these bacteria influence brain structure.
“Overall, our study supports the view that an interventional approach using probiotic strains (including order Bacillales and Lactobacillales), prebiotics, and potentially fecal microbiota transplantation therapy may be an effective initiative to improve brain function, taking into account cost, feasibility, and patient compliance,” the researchers noted.
“By modulating the composition of the gut microbiota and regulating the interaction within the gut-brain axis, these interventions hold potential therapeutic value for various neurologic disorders. However, further clinical research is needed to verify the safety, efficacy, and treatment protocols of these interventions,” the researchers added.
Reference
The study titled, “Association of gut microbiota with cerebral cortical thickness: A Mendelian randomization study,” was authored by Lubo Shi, Xiaoduo Liu, Shutian Zhang, and Anni Zhou.
