Our bodies are complex systems with a lot of secrets we still need to uncover. It is only in recent years that we have become aware of the unexpected connection between our brains and bacteria living in our gut (microbiota).
It has become clear that the disruption of our microbiota contributes to anxiety, mood changes, cognition impairment, and various diseases, including central nervous system disorders, autism, and multiple sclerosis. This signaling pathway is called the gut-brain axis, and we are still discovering different mechanisms behind it.
A new study published in the Microbiome journal suggests that consuming kefir could increase GABA neurotransmitter production, which plays a vital role in our cognition and the regulation of anxiety.
Multiple recent studies concluded that fermented foods could have a positive effect on mood, and researchers from the APC Microbiome Ireland, in collaboration with numerous scientists from the University College Cork, wanted to test the effects of kefir. Kefir is a dairy product made from fermented milk and grain, and its taste is similar to yogurt.
Experiments were performed on four different mice groups, where every group received a different intervention over two weeks:
- The first group – consumed unfermented cow’s milk
- The second group – consumed Fr1 kefir
- The third group – consumed UK4 kefir
- Lat group – had no intervention
Mice performed a series of tests to determine how individual interventions affected their behavior. Additionally, researchers analyzed caecal, ileal, and fecal matter, and investigated the change of host’s microbiota. On top of that, they analyzed specific biomarkers connected to the immunity status, as well as gut serotonin levels. Serotonin signaling is known to play an essential role in communication between microbiota and a host.
The results showed that both kefirs had a positive impact on the host’s microbiota and the gut-brain axis. However, while two types of kefir had a positive effect, they didn’t have the same outcomes.
Kefir Fr1 increased reward-seeking behavior and improved levels of some stress-induced molecules. UK4 decreased repetitive behavior, improved immune response, and reduced stress effects. It additionally increased fear-induced contextual memory, but a slight drop was observed in long-term spatial learning.
Both kefirs affected the host’s microbiota and increased capacity for GABA secretion.
Why is this important?
Affecting GABA neurotransmitters has the potential to reduce anxiety and symptoms of depression. Although this study was performed on mice, these positive results can pave the way for future human studies.
This experiment shows that kefir has an ability to affect microbiota and gut-brain axis, changing mice’s behavior along the way. More studies are needed to determine why different types of kefir affected hosts differently upon consumption. That can help us get one step closer to human trials and more quality research.
If the results show positive, we can label kefir as a new functional food for improving mood and behavior, while reducing anxiety symptoms.