‘Promising’: Multi-strain probiotic may held modulate behavior in healthy people

By Stephen Daniells

- Last updated on GMT

© Getty Images / ChrisChrisW
© Getty Images / ChrisChrisW
Supplementing the diet with a combination of different probiotic strains may modulate behavior in healthy volunteers, says a new RCT from Austria that supports the role of the gut-brain axis.

Brain imaging technology (fMRI) indicated that four weeks of supplementation with Winclove’s Ecologic 825 product led to significant changes in functional connectivity of various regions and networks in the brain, which suggested that the probiotics may be impacting higher order cognitive processes as well as emotional ones.

The study product is composed of nine bacterial strains, including Lactobacillus casei​ W56, L. acidophilus​ W22, L. paracasei​ W20, Bifidobacterium lactis​ W51, L. salivarius​ W24, Lactococcus lactis​ W19, B. lactis​ W52, L. plantarum​ W62, and B. bifidum​ W23.

“This work provides new insights into the role of a multi-strain probiotic administration in modulating the behavior, which is reflected as changes in the FC [functional connectivity] in healthy volunteers,”​ wrote the scientists in the European Journal of Nutrition​.

“This study motivates future investigations into the role of probiotics in context of major depression and stress disorders.”

“Adding to the gut-brain-axis literature”

Commenting independently on the findings of the research, Dr Jessica Ter Haar, PhD, scientific director at the International Probiotics Association, called the study “promising”.

“This study that adds to the gut-brain-axis literature in a very concrete way,”​ she said. “The integration of hard neuroscience imaging techniques with probiotic science is a continuing sign of encouraging multidisciplinary progress in the field.”

Dr Ter Haar said that while probiotic consumption led to differences in functional neural networks compared to placebo and control groups, no structural changes were noted in the white matter architecture associated with the functional connectivity networks after four weeks of administration.

“Perhaps long-term intake or a different dosing regime would be required to further evaluate if probiotic administration can influence structural neural architecture,” ​she said.

Study details

Probiotics © Getty Images image_jungle
The study used a combination of nine difference probiotic strains. Image © Getty Images / image_jungle

Scientists from the University of Graz and Graz University of Technology (Austria) recruited 45 healthy volunteers and randomly divided them into three equal groups. One group received the multi-strain probiotic product, one group received placebo, and one group received nothing (control group). fMRI scans were performed at the start of the study and again at the end (after four weeks).

Results showed that the probiotic group displayed changes in functional connectivity (FC) in various brain regions, including the default mode network, salience network, and middle and superior frontal gyrus network, compared to the other two groups.

Notably, probiotic consumption was associated connectivity increases in areas of the salience network called the cingulate gyrus and precuneus cortex.

“Changes in FC in this region in [probiotic] group reflect an influence of probiotic administration on modulating behavior and a shift towards efficient attentional control,”​ explained the researchers. A 2018 study by Bagga et al. (Gut Microbes​, Vol. 9, Issue 6​) reported that changes in functional connectivity in this part of the brain that were associated with emotional decision-making, “reflecting the role of this region in emotional processes”.

Filling the gaps

The researchers concluded: “The present study […] have demonstrated that there is a close relationship between the effects of probiotic intervention on behavioral and neuroimaging readouts.

“However, studying the molecular mechanisms associated with probiotic intervention in humans is still an important question for future investigations in this field. Deeper understanding of these molecular mechanisms will definitely influence their clinical use in the future and potentially lead to new and specific formulations of probiotics, which might protect against a wide range of mood disorders and thus can revolutionize the field of therapeutics.”

IPA’s Dr Ter Haar commented that while the study included healthy individuals, she would have liked to have data presented on any adverse events and also a discussion of the study limitation. “These are essential elements for the progression of the field that should be included in any study involving probiotic administration in humans,” ​she said.

Source: European Journal of Nutrition
August 2019, Volume 58, Issue 5, pp 1821–1827, doi: 10.1007/s00394-018-1732-z
“Influence of 4-week multi-strain probiotic administration on resting-state functional connectivity in healthy volunteers”
Authors: D. Bagga et al.

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