Studies are increasingly finding strong connections that gut microbes influence brain health.
In a recent study published in Clinical Nutrition, researchers from the University of North Carolina at Chapel Hill found that probiotics might help people with memory-related issues as they age.
The team found that a group of people in their middle age who were experiencing mild memory lapses and difficulty with language and decision-making got better when they were given probiotics for three months.
That was not all. The researchers also observed that people with these mild cognitive symptoms had a specific type of bacteria called Prevotella in their stomachs.
“The implication of this finding is quite exciting. Modifying the gut microbiome through probiotics could potentially be a strategy to improve cognitive performance, particularly in individuals with mild cognitive impairment [MCI],” said Mashael Aljumaah, lead author of the study, in a statement.
The gut-brain link
Millions of bacteria live in the human gastrointestinal tract, particularly in the colon. They help digest food and provide useful chemicals for our bodies. Some bacteria produce neurochemicals beneficial for brain health.
Previous studies have reported that as people age, their gut microbes also get altered compared to the microbial population in healthy people. Although the ageing person is fairly independent, the changes in the gut could be a precursor to cognitive impairments causing mild symptoms.
The current study’s researchers showed that probiotics could help maintain healthy microbes in the gut of ageing adults. Yoghurt is an example of a probiotic that helps replenish these microbes in our gut.
“Intervention at this stage of cognitive impairment [mild cognitive problem with ageing] could slow down or prevent the progression to more severe forms of dementia,” says Aljumaah.
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The influence on cognition
The researchers chose 169 adults in the 52-75 age group for their study. The participants lived independently within a community and not in care facilities. They were divided into two groups: healthy adults without neurological conditions (control group) and healthy adults with MCI.
The group with MCI was given probiotic supplements (a known bacterial type that is beneficial for health). In contrast, the control group was given a placebo.
The researchers used genomic techniques to assess the gut microbe environment and neuropsychological assessment (questionnaires) for evaluating cognitive functions. They did this once before the commencement of the experiment and once after three months of giving the probiotics.
The researchers found that adults with MCI had poor cognitive performance and an abundance of Prevotella compared to healthy adults. However, after receiving the probiotics for three months, their cognitive performance improved. Moreover, the Prevotella abundance in the MCI group had reduced.
“We found unique differences in certain gut bacteria, like Prevotella, between individuals with mild cognitive impairment and cognitively healthy individuals,” Dr Aljumaah told Happiest Health.
She adds that this is a direct comparison with healthy individuals, unlike earlier studies comparing mild and severe cognitive impairments.
Need for good bacteria
Aljumaah went on to explain that their study helps gain insights into early cognitive decline changes. This early-stage information offers potential for timely interventions, possibly slowing or reversing cognitive disorder progression.
Dr Ashwani Garg, a medical practitioner at the Functional Medicine Clinic in Bengaluru, concurs with Aljumaah that probiotics play a vital role in maintaining digestive, immune and brain health. For example, he says dopamine (a brain chemical) is high in attention deficit hyperactivity disorder (ADHD). A widely accepted link is that this is due to Clostridium bacterial infection. This infection obstructs the conversion of dopamine into epinephrine (a neurotransmitter), which provides a calming effect and helps reduce ADHD symptoms.
“Inhibition of dopamine conversion to epinephrine causes higher dopamine secretion in the brain,” says Dr Garg. He adds that if we give a probiotic to reduce the clostridium infection, dopamine will start converting into epinephrine.
Natural probiotic foods such as yoghurt, soya bean milk, and fermented cabbage can be used as a daily supplement.
Aljumaah says their findings—should they be replicated in future studies—opens the possibility of using gut microbiome-targeted strategies to support cognitive health.
