Probiotics Show Promise in Alzheimer’s Disease

Guest BloggerMicrobiome Environment


A popular gift this holiday was a genetic testing kit. Priced reasonably and readily available without a prescription online and in stores, the DNA tests focus on ancestry and health.

You may be delighted to discover a few ancestors hailed from Africa. On the other hand, you may find out your dad is not that man living with your mom. And then when looking at the health results, you may find out celiac disease is not likely but that you have a pretty high chance of getting Alzheimer’s.

One big downside with DNA tests is that a little knowledge may be a maddening thing. Even with all of  the world’s medical marvels, you may not be able to stop the train that leads to a disease as heartless as Alzheimer’s.

Yet researchers are working overtime to find preventions or treatments for Alzheimer’s disease as the losses accelerate. Suspects in its shadowy etiology include brain trauma, toxins, pollution, sleep deficits, poor diet, inactivity, infection, inflammation, and now, microbes.

Researchers are seeing more evidence of the last one in the gut-microbe link. Much of that comes from animal studies. In one earlier trial, lactic acid bacteria and bifidobacteria given to mice improved cognitive function as well as biomarkers noted on a healthy gut-brain axis.

In a new report in Experimental Gerontology, probiotics together with exercise reduced the development of Alzheimer’s disease in mice. Scientists Dora Abraham and colleagues used APP/PS1 (mutations associated with early-onset Alzheimer’s disease) transgenic mice.

The mice were subjected to exercise training and probiotic treatments. Functional, biochemical and microbiome markers were analyzed.

Functional tests

The experimental mice outperformed controls on the Morris Maze Test (widely used in behavioral neuroscience to study spatial learning and memory.)

Biochemical analysis

The number of beta-amyloid plaques decreased in the hippocampus of experimental mice.

Microbiome markers
  • Bacteroides thetaiotaomicron levels correlated highly with the results of the Morris Maze Test. They were significantly elevated in the microbiome of the APP/PS1TG mice compared to the wild type.
  • B. thetaiotaomicron level is correlated with poor spatial memory which can be countered by exercise and probiotics.
  • Lactobacillus johnsonii levels positively correlated with the beta amyloid content and area.

The authors concluded:

Data revealed that exercise and probiotic treatment can decrease the progress of Alzheimer’s disease and the beneficial effects could be partly mediated by alteration of the microbiome.

Of Microbes and Minds: A Narrative Review on the Second Brain Aging, an excellent analysis published by Italian researchers in March of 2018 in Frontiers in Medicine, reminds us that microbes may figure in neurological diseases such as Alzheimer’s in other ways:

Microbes may:
  • Program the activity of multiple neurotransmitter systems in different brain regions.
  • Play a role in synapse maturation and synaptogenesis.
  • Be altered by antibiotics by affecting microglia in the short and long-term.

The gut-brain axis holds exciting possibilities in combatting Alzheimer’s— whether or not you know your chances of getting it.