Using probiotic supplements for 12 weeks improved cognitive ability and sleep quality of Chinese patients with mild cognitive impairment, a randomized controlled trial shows. Randomized controlled trials prospectively study how effective an intervention or a drug is on patients with a certain disease. It is the gold standard for effectiveness studies. 

People with mild cognitive impairment are capable of performing daily activities, however, they can notice the changes in their memory and thinking skills, so as their families and friends. This condition does not necessarily progress to Alzheimer’s disease, but 10-15% of people with mild cognitive impairment developed Alzheimer’s each year. 

Microbiome contains microbes, including bacterium, fungus, virus, and parasite. A well-balanced microbiome in the gut is critical, due to its benefits on various systems in our body, such as the digestive, immune, and nervous system. To adjust the balance of gut microbiome, people can take probiotics that are live and friendly bacteria or yeast from fermented food, or supplements.

Previous studies have found that individuals with declined cognitive ability, or Alzheimer’s showed imbalanced gut microbiome, compared with healthy people. This suggests that gut microbiome health could be a key target for treating cognitive ability decline or certain stages of Alzheimer’s.

To explore how probiotics affect cognitive ability of elderly individuals with mild cognitive impairment over 12 weeks, the researchers randomly split 40 participants to two groups. One group of 20 participants received probiotics, the other group received starch capsules as a comparator. They used the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment Scale (MoCA) tests to assess the participants’ cognitive ability; the Pittsburgh Sleep Quality Index (PSOI) questionnaire to evaluate individuals’ sleep quality. 

The probiotics notably improved the cognitive ability of the participants, as both the MMSE and MoCA test results in the probiotics group improved, compared with the comparator group. Particularly, the participants’ ability to concentrate and calculate, as well as their short-term memory, executive ability, and visuospatial capability improved significantly. 

The probiotics also improved participants’ sleep quality, including time to fall asleep, sleep duration, and sleep disorder, compared with individuals in the comparator group. Also importantly, the participants who used the probiotics did not report any side effects. 

In the published paper, the authors also discussed the possible reasons that explain the beneficial effects of the probiotics. The probiotics improved the gut microbiome system, which may reduce the inflammation levels in the body, and specifically in the brain. Improved gut microbiome may also increase the levels of neurotransmitters released by the gut microbes. Neurotransmitters are the chemicals, such as dopamine, that help nerve cells in the brain communicate with each other, or with other types of cell, such as muscle cells. These reasons together contributed to the improvements shown in the study participants. 

“MCI is often clinically ignored because its early symptoms are not obvious. It has been reported that MCI patients advance to AD at a rate of 10%-15% each year. If timely prevention or treatment of MCI is administered, the risk of AD could be effectively reduced,” wrote the authors. 

“Nonpharmacolgical therapies for treating MCI are easier for patients and their families to understand and accept. Our findings provided favorable evidence for the use of probiotic supplementation in the clinical nutritional intervention of MCI patients.”

This article serves the purpose of bringing the findings from this recent study to the general public. It aims to raise people’s awareness of the possible options to improve cognitive ability, prevent cognitive ability decline, or delay Alzheimer’s symptoms for those at risk. Before taking probiotics, patients and their families should have conversations with physicians for advice on appropriate and safe use of the supplements, as well as for achieving optimal outcomes.  

This study was published in Geriatric Nursing. Image credit: Pixabay

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