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A wider view of the gut-brain link

A wider view of the gut-brain link

Researchers have found that in older adults with mild cognitive impairment there is an increase in total viruses and a decrease in bacterial abundance in their gut microbiomes
An illustration showing a connection between the gut and the brain
Representational image | Sutterstock

We all know the gut and the brain are linked. But do we really? Studies have established the link between the gut and the brain, but the mechanism remains unclear. We are yet to understand how the gut actually influences the brain and vice versa.

To better understand this, researchers at the University of South Florida’s Center for Microbiome Research conducted a study. They analysed gut samples collected from individuals with mild cognitive impairment (MCI) and compared them to samples from cognitively healthy older adults.

There have been other studies that analysed gut bacteria. But this study went further and utilized whole-genome metagenomic sequencing, which allowed them to analyze the entire genetic content of the gut microbiome, including viruses and other microorganisms. They hoped to find microbiome signatures that could someday help predict the risk of cognitive decline and dementia in older adults.

“…the results from our pilot study indicate that trans-kingdom microbiome signatures are significantly distinct in MCI gut compared with controls and may have utility for predicting the risk of developing cognitive decline and dementia,” the researchers wrote.

In doing this, they found out that older adults with MCI have a less diverse gut microbiome. They also found that there was an increase in total viruses and a decrease in bacterial abundance compared to the control group.

Cognitive function in older adults

Cognitive impairment refers to difficulties in memory, attention, language, problem-solving, and decision-making. This significantly affects individuals’ daily functioning and their overall quality of life.

Currently, no treatments exist to reverse age-related cognitive decline. However, if caught early, the condition can be slowed down significantly. This gives diagnosed individuals a chance at leading a normal life for longer. It is here that the gut-brain axis gains significance; it could herald new treatments for MCI and other cognitive disorders using targeted dietary changes.

“By conducting larger and diverse studies, we can develop personalized dietary interventions to better manage and support cognitive health in older adults,” said Aditi Prabhu, a clinical dietician and nutritionist from Mumbai who focuses on gut and mental health.

Moreover, understanding the role of the human virome in health and disease is becoming increasingly important. This too could inform us of better strategies to enhance mental well-being and overall health through dietary interventions, says Dr Priyanka Sarkar, a post-doctoral research associate at the Asian Institute of Gastroenterology in Hyderabad.

Advanced methods

In the past, scientists used a method called 16S rRNA sequencing to study the gut microbiome. This method focused on examining the abundance of bacteria, but it missed important things like viruses, fungi, and archaea, as well as how everything works together in the gut community.

However, new methods are taking a more comprehensive approach by exploring different types of microbes and their overall functions. This way, we can better understand the complex link between the gut microbiome and cognitive health in older people.

Gut and mental health

As part of their study, researchers at the University of South Florida’s Center for Microbiome Research stumbled onto how butyrate possesses abilities to influence our cognitive abilities. Their research showed that butyrate can block a protein called HDAC, which inhibits specific genes linked to memory, learning and brain function.

Clearly, the research suggests strong links between butyrate-producing bacteria and mental health. “Short-chain fatty acids, especially butyrate, play vital roles in supporting a healthy gut-brain connection, offering potential as a treatment for brain disorders in both medication and nutrition. Research shows strong links between butyrate-producing bacteria and mental health, pointing to promising therapeutic uses,” adds Dr Sarkar.

So, does this really establish a clear mechanism that seems to link the gut with the brain? Perhaps not. However, this does move us closer to understanding it better than before. Studies like these can pave the way for innovative strategies that enhance our mental well-being and cognitive functions.

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One Response

  1. Good study to elucidate brain-gut bacteria axis especially in older population. This pilot study may be inspired other researchers to evaluate it’s meechanism which may be helpful to find out suitable medical modaliity to manage old aged diseases.

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