New research from Örebro University has shown that the format of a probiotic can influence how it affects the brain.
The data points to new possibilities for personalised approaches, depending on whether the primary aim is, for example, to improve memory or reduce depression.
"Personally, I didn't think it would make much difference how we consume probiotics," said Julia Rode, researcher in biomedicine at Örebro University with a particular focus on the connection between the gut and the brain.
Our study shows that memory and concentration can change if the probiotic powder is encapsulated, whereas powder that is not encapsulated has a greater effect on mental health, such as anxiety, depression and similar conditions.
Probiotics are beneficial bacteria that support brain health and are typically consumed through food or functional beverages.
How the bacteria are prepared plays a major role in storage and shelf life. They also behave differently in the gastrointestinal tract, thereby affecting the brain.
Encapsulated powder is analogous to baking powder, which also comes in various forms. The coating allows it to remain active longer and to avoid immediate reactions, for example, with dough.
Similarly, encapsulated powder enables a greater proportion of beneficial bacteria to reach deeper into the gut.
"We saw that the form had different effects on the brain. It's not that one form is better than the other — it depends entirely on what the individual needs to strengthen. Different preparation methods are useful in different situations," explained Rode.
The study
The research used 87 people, aged 60-80.
Participants were given either microencapsulated or non-encapsulated probiotic bacteria from the same strain and at the same dose. A control group received a placebo to compare results.
The results showed clear differences in the brain's functional connections, depending on how the probiotics were taken.
These findings reinforce the connection between the gut and the brain—the so-called gut-brain axis—and its potential contribution to healthier ageing.
The form of the powder had different effects on brain function. Encapsulated powder affected cognition, including memory, focus, attention and orientation.
Non-encapsulated powder affected mental health, which may influence low mood, anxiety and depression.
An increasing number of studies indicate that the gut microbiota influences the brain and, in turn, ageing.
In this study, participants received probiotics in various forms and the effects on the brain were assessed using magnetic resonance imaging (MRI), brain function tests and questionnaires.
The study is the first to be conducted in healthy older adults and to compare different methods of preparing probiotics. A small number of previous studies have demonstrated a link between the gut and the brain using magnetic resonance imaging (MRI).
"Probiotics are beneficial for brain function," said Rode.
With data from this study, we can hopefully contribute further to our understanding of how probiotics can be consumed, for example, to cope with stressful periods.