Probiotics are often promoted for gut health, but scientists are increasingly discovering that these “good bacteria” may also affect the brain.
A new study from Örebro University in Sweden suggests that the way probiotics are taken—whether in encapsulated form or as plain powder—can influence whether they help more with memory and concentration or with mood and emotional well-being.
The research, published in the journal Brain, Behavior, and Immunity, highlights the growing importance of the gut-brain connection, sometimes called the gut-brain axis.
This is the communication network linking the digestive system and the brain, which researchers believe plays a role in mental health, cognitive function, and even aging.
In the study, scientists focused on healthy adults aged 60 to 80.
A total of 87 participants were given probiotics containing the same bacterial strain and dose, but in different forms. Some received microencapsulated powder, which is coated so it can survive longer and travel deeper into the intestines before being released.
Others received non-encapsulated powder, which dissolves more quickly. A third group received a placebo for comparison.
Researchers then used brain scans, cognitive tests, and questionnaires to measure changes in brain function, memory, attention, and mood. The results revealed clear differences depending on how the probiotics were prepared.
Participants who took the encapsulated form showed improvements in cognitive abilities such as memory, focus, attention, and orientation. Scientists believe this may be because the protective coating allows more of the beneficial bacteria to reach parts of the gut that influence brain processes linked to thinking and learning.
By contrast, those who took the non-encapsulated powder experienced greater benefits related to emotional health. These participants showed changes associated with lower anxiety, reduced depressive symptoms, and improved overall mood. Researchers suggest that the quicker release of bacteria in the gut may affect pathways tied more closely to emotional regulation.
Lead researcher Julia Rode noted that the findings surprised the team. They had not expected the form of the probiotic to matter so much. Instead, the results suggest that probiotics could potentially be tailored to individual needs.
For example, someone looking to support memory and concentration might benefit more from encapsulated probiotics, while someone dealing with stress or low mood might respond better to the non-encapsulated form.
The study is among the first to compare different probiotic preparations in healthy older adults using brain imaging. While more research is needed, the findings open the door to personalized nutrition strategies aimed at supporting brain health as people age.
Scientists emphasize that neither form is universally better than the other. Rather, each may serve different purposes depending on a person’s health goals. As research into the gut-brain connection continues, probiotics could become a more targeted tool for supporting both cognitive function and emotional well-being.
