Taking a daily probiotic may help slow age-related cognitive decline

Evan Walker
Evan Walker TheMediTary.Com |
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Research suggests that manipulating gut bacteria could hold promise for addressing cognitive impairment and other conditions. Nes/Getty Images
  • Results from a clinical trial showed that people with mild cognitive impairment who were given a probiotic for 30 days scored higher on cognitive tests.
  • After the trial, the gut microbiome of participants who took probiotics contained less of a type of bacteria associated with cognitive impairment.
  • The findings suggest that manipulating gut bacteria could hold promise for addressing cognitive impairment and other chronic conditions.

A clinical trial suggests that treatment with a probiotic could help people with mild cognitive impairment (MCI) regain cognitive function.

With the worldwide surge of dementia and Alzheimer’s disease (AD), “there is an urgent need for more research,” said lead study author Mashael R. Aljumaah, a microbiology doctoral candidate at the University of North Carolina at Chapel Hill.

During the double-blind randomized trial, people with cognitive impairment received a daily probiotic — Lactobacillus rhamnosus GG — for three months, after which their scores on cognitive tests improved.

Analyzing participants’ stool samples, the researchers found substantial levels of Lactobacillus rhamnosus GG, or LGG, as well as a reduction in the amount of another family of bacteria, Prevotella, often observed in people with cognitive decline.

These changes suggest a beneficial shift in the composition of participants’ microbiome.

“LGG [bacteria] emerged as a potential therapeutic probiotic based on numerous previous animal studies, which demonstrated its positive effects on several physiological conditions. LGG is also known for its acid tolerance and its ability to adhere in the gut, which makes it an effective probiotic.”

– Mashael R. Aljumaah, lead study author

The research is being presented at the NUTRITION 2023 gathering in Boston, MA, this week. The clinical trial results were also published in the scientific journal Clinical Nutrition in 2022.

For the study, researchers compared people with mild cognitive impairment to those without the condition.

They sought to observe, understand, and attempt to influence the early stages of cognitive decline. Part of that effort involved identifying biomarkers that may signify the beginnings of cognitive impairment.

Researchers enrolled 169 participants varying in age from 52 to 75 years old in the clinical trial. People without cognitive impairment were assigned to one group as a control, and those with cognitive issues were assigned to another group.

Both groups received either LGG or a placebo for three months. No adverse effects were observed in either group.

Aljumaah and her colleagues identified one such biomarker, Prevotella, in people with cognitive impairment. The fact that the receipt of LGG appeared to reduce its presence suggests the sort of microbiome re-balancing that may one day be possible.

“By designing microbiome-targeted interventions, we can potentially slow down the progression of cognitive impairment,” Aljumaah told Medical News Today.

Dr. Santosh Kesari, a board certified neurologist and director of neuro-oncology at the Pacific Neuroscience Institute in Santa Monica, CA, who was not involved in the study, told MNT he found the delivery of cognitive benefits to participants “intriguing.”

Still, Dr. Kesari called for larger studies to confirm its findings and ensure that no toxicities result from introducing LGG bacteria.

In addition, he expressed concern that an effort to solve a problem by introducing a probiotic to the gut microbiome may unbalance its bacterial mix, causing adverse effects.

“Focusing on a positive effect on brain Health could have a counterproductive effect in another organ system,” Dr. Kesari said.

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