Taking a Probiotic May Help Slow Age-Related Cognitive Decline, New Study Finds

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• Taking a probiotic may help prevent or reverse some mild cognitive issues associated with old age, researchers say.

• Though the study is considered preliminary, adults who took a probiotic for 12 weeks saw improvements in their cognitive scores.

• The research is "valuable" but it’s just a starting point; more research is needed to further explore the gut-brain connection.

For some people, taking a probiotic may help prevent or reverse some of the mild cognitive issues that come with old age, new research shows.

The news comes from a study presented Monday at NUTRITION 2023, the annual meeting of the American Society for Nutrition, in which researchers looked at a group of middle-aged and older adults with mild cognitive impairment—slightly worse memory and thinking issues than what’s seen in most older adults—and the effects that regular probiotic supplementation had on their cognition.

Though the study is considered preliminary, researchers observed that the adults who took a probiotic for 12 weeks saw improvements in their cognitive scores as compared to baseline.

“Those individuals that got that probiotic seemed to have some improvements in their memory score—so potentially suggesting that this could reverse some of the cognitive changes and other stuff that’s going on,” said Beau Ances, PhD, MD, Daniel J. Brennan professor of neurology at Washington University School of Medicine in St. Louis, who was not involved in the new research.

In addition to the potential cognitive benefits of probiotics, researchers also found that the composition of the bacteria in a person’s gut could be used to identify these cognitive issues.

Together, the findings could suggest new ways to identify and maybe even treat mild cognitive impairment in the future.

The Brain-Gut Connection

To further tease out the connection between cognition and gut health, study authors included 169 participants between the ages of 52 and 75, and split them into groups based on whether they were experiencing mild cognitive impairment.

Within each group, participants were given either a placebo or a probiotic supplement called Lactobacillus rhamnosus GG (LGG), which they took for three months.

Each person has a collection of bacteria, fungi, and other microbes that live in their body, known as the microbiome. These organisms help people digest food, develop an immune system, and stay protected against pathogens.

Probiotics such as LGG can help maintain healthy levels of microbes in the gut or can reestablish healthy levels if the microbiome has been disturbed in some way.

Researchers wanted to see whether people with mild cognitive impairment had different microbiomes as compared to people who were cognitively normal, explained study co-author and presenter Mashael Aljumaah, a PhD candidate at North Carolina State University. They also wanted to know if taking a probiotic and changing that microbiome would in turn change cognition.

Researchers monitored the specific bacteria in people’s guts via stool samples.

“After the intervention period, we also collected samples again—so we have stool samples at baseline and stool samples post-intervention,” she told Health. “We were able to see specific changes in the gut microbiome that were associated with improvement in the cognitive scores.”

But the probiotic wasn’t a memory-booster across the board—those participants with normal cognition at the beginning of the study didn’t see any cognition improvements even after taking the LGG probiotic.

This may have been because people with mild cognitive impairment had elevated concentrations of a certain bacteria called Prevotella in their guts, the study said. After taking the probiotic, those levels of Prevotella decreased and people’s memory improved.

However, the relationship between high levels of this bacteria and brain health aren’t yet clear, said Aljumaah.

Some research has shown Prevotella to be a good bacterium, associated with a plant-rich and fiber-rich diet, she explained.

“On the other hand, there are studies that are associating it with autoimmune diseases and inflammatory diseases. And so the literature is kind of split,” she said.

She and her team are currently working on research on Prevotella to see if this might be one of the culprits behind the microbiome’s effect on cognition.

Even though this study showed a connection between the bacteria living in people’s guts and their memory function, there’s still much that researchers don’t yet know about how the two impact one another.

“Your gut is one of the most innervated [body systems]—meaning the most number of nerves in your body go to your gut,” Ances said. “If you’re really hungry, you tell your brain and then you go and you eat something. So there’s this constant contact between the gut and the brain.”

The microbiome is also involved in the production of neurotransmitters and of fatty acids, which is thought to help the gut and brain communicate. There’s much that’s unknown, but the gut and the brain likely have a strong connection.

One theory of how gut health affects the brain is called leaky gut—if some bacteria seep out of the gut and into the bloodstream, they could cause inflammation that spreads to the brain and harms it in some way, Ances explained. But for now, there are no sure answers.

It’s also important to remember that the gut microbiome is just one piece of the puzzle when it comes to figuring out how to prevent or cure cognitive impairment, Aljumaah said.

“We know for a fact that your level of education, your genetic background, your lifestyle—all of these play a role in your cognitive status,” she said. “If we can manage that one component or one risk factor, I think hopefully we can get better outcomes. But it’s never only the microbiome that is driving changes in your cognition. It’s a multifactorial thing.”

Related: Taking a Daily Multivitamin May Help Slow Memory Loss in Older Adults

A Burgeoning Area for Research and Treatment

Aljumaah emphasized that this research is “valuable,” but it’s just a starting point. More studies will be needed to explore the brain-gut connection, as well as what the microbiome or probiotics can do, the experts said.

In other words, it’s too soon to say that probiotics can be used as a treatment for mild cognitive impairment. However, the findings add to a growing body of research and present the potential for some interesting diagnostic or therapeutic solutions.

For one, the gut microbiome could be an easy way to tell if someone is suffering from cognitive impairment.

In June, Ances was part of a research team that found changes in the gut could indicate patients that had preclinical Alzheimer’s disease, which means they have early biological changes seen with AD but are asymptomatic and do not have any cognitive symptoms. Similar to Aljumaah’s findings, this implies that looking to the gut could be another way to catch memory issues early.

Other preclinical tests for Alzheimer’s already exist—people can get brain imaging, a blood or spinal fluid test, or cognitive assessments. However, there can be issues with access, Ances said, particularly for underrepresented groups.

“If you have a stool sample, it’s pretty easy to collect, and evaluate,” he said.

When it comes to probiotic use and improvement in cognitive function, that could be another simple option to help people.

The LGG probiotic—the one used in the study—is one of the most common probiotics out there, and people can typically find it at any local grocery or health store, Aljumaah said. And probiotics are generally safe, especially in healthy people.

Again, studies like these need to be replicated and more research needs to be done before we can say with certainty that probiotics can help people with mild cognitive impairment see improvement in their memory and thinking.

But probiotics do have a host of other potential benefits—research has linked probiotics to preventing or treating diarrhea, atopic dermatitis, irritable bowel syndrome, and more.

Before starting supplements, including probiotics, it’s important that people speak to their doctor beforehand, Aljumaah said.

Another easy way to keep the microbiome thriving is to switch up your diet, Aljumaah added. Fermented foods such as yogurt, kimchi, or kefir can be a great way to boost gut health.

Related: The Right Probiotics for Your Stomach Problems

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Read the original article on Health.