This Probiotic Combination Was Linked To Better Mood & Higher BDNF Levels
Have you ever had butterflies before a big presentation? Or completely lost your appetite after bad news? Most of us have experienced our brain affecting our gut. But scientists are becoming just as interested in the opposite question: could the gut influence the brain?
That idea sounded far-fetched not long ago. Today, it's one of the fastest-growing areas of mental health research. Rather than suggesting the microbiome is the cause of depression, researchers are uncovering how the bacteria living in our digestive tract may influence stress, inflammation, and the brain itself. A new clinical trial adds another piece to that story, exploring whether specific probiotics can support people already receiving treatment for depression.
A closer look at the study
To explore whether the gut microbiome could play a role in depression treatment, researchers recruited 58 adults over the age of 60 who were living with moderate depression. Everyone in the study continued taking their prescribed antidepressant medication. The only difference was that half of the participants also took a daily probiotic containing two well-studied strains, Lactobacillus helveticus and Bifidobacterium longum. The other half received a placebo.
Over the next 12 weeks, researchers checked in on much more than mood alone. They tracked changes in depression and anxiety symptoms, cognitive function, quality of life, and even biological markers that might help explain what was happening behind the scenes.
What they found
Everyone improved over the course of the study, which is exactly what you'd hope to see when people are receiving appropriate treatment for depression. But the group taking probiotics consistently reported slightly greater improvements in both depression and anxiety.
They also found that participants taking the probiotics had higher levels of brain-derived neurotrophic factor (BDNF), a protein that's essential for helping the brain form new connections, adapt, and learn. It's often nicknamed "fertilizer for the brain" because it supports neuroplasticity, or the brain's ability to change and remodel itself throughout life.
Researchers also confirmed that the probiotic strains had successfully established themselves in participants' gut microbiomes. While that doesn't prove the bacteria caused the mood improvements, it does strengthen the idea that changing the gut environment may influence the brain through real biological pathways.
Supporting your gut-brain axis
This study is another reminder that the health of your gut is shaped by what you do every day. While certain probiotic strains may eventually become part of depression treatment, your microbiome responds to far more than supplements.
Here are a few everyday habits that support a healthier, more diverse microbiome:
- Eat a wide variety of fiber-rich plant foods
- Include fermented foods like yogurt, kefir, kimchi, sauerkraut, or miso
- Exercise regularly, which has been linked to greater microbial diversity
- Prioritize quality sleep
- Manage chronic stress through meditation, breathwork, journaling, therapy, or time outdoors
- Limit ultra-processed foods while making room for plenty of whole, minimally processed ingredients
The takeaway
Depression remains a complex medical condition that deserves comprehensive care. Probiotics aren't a replacement for therapy, medication, or other evidence-based treatments. But this study suggests they may eventually become one more tool clinicians can use alongside those approaches.
In the meantime, caring for your gut isn't just about digestion. It's one more way to support the complex network connecting your brain, immune system, and body, helping you better handle stress and supporting your mental health over time.
