Most of us don’t really think about the relationship between our brain and our gut. In fact, many people don’t even realize how closely connected the two are. 

Your brain and gut have a bidirectional relationship. This means that our mental health can affect our gut, and our gut can impact your brain function. Have you ever gotten stomach aches when you’re stressed? Or felt brain fog when you’ve had an unhealthy meal? Those are examples of this relationship at work.

The brain-gut axis

The brain-gut axis is a complex system connecting the central nervous system (including the brain and spinal cord) to the enteric nervous system (located in the gastrointestinal tract). This connection extends beyond just physical interactions, including hormonal communication, immune responses, fluid regulation, and metabolic processes.

The enteric nervous system, often referred to as our “second brain,” plays an important role in communicating vital information from our gut to our brain. Our gut houses a vast microbiome, a diverse colony of bacteria instrumental in digestion, mood regulation, immune function, and nutrient absorption.

Neurotransmitters, the brain’s chemical messengers, are the molecules that can move between the gut and brain. They communicate messages between the brain and gut. Interestingly, neurotransmitters are produced both in the brain and the gut, with adjusting nerve activity producing molecules that function similarly. Our gut is home to approximately 100 trillion microorganisms, encompassing over 500 different species, with each individual hosting a unique bacterial composition.

It’s easy for our gut to get out of balance. From eating highly processed, fatty, sugary foods, to taking antibiotics and other medications that kill the good bacteria in our gut, we sometimes need some additional assistance to keep things on track. This is where probiotics come into play.

Maintaining this delicate gut balance can be challenging. Factors like eating processed foods high in fat and sugar, alongside antibiotics and other medications that can kill beneficial bacteria in the gut, can disrupt this balance. Probiotics can be vital in restoring and maintaining this balance, offering necessary support for our intricate brain-gut axis.

What are probiotics

Probiotics are live microorganisms that are taken to support your health.  You can find them in fermented foods like yogurt, sauerkraut, kimchi, kombucha and kefir and are also often put into  dietary supplements. These beneficial bacteria play a critical role in supporting both gut health and brain function. 2 

Among the diverse types of beneficial bacteria, Lactobacillus and Bifidobacterium are two of the most common. Each category consists of different species, each with unique roles. Some species help with digestion, nutrient absorption, and the breakdown of carbohydrates. Others contribute to immune function, combat harmful bacteria, and protect against foodborne pathogens. 3

Probiotics work by changing the bacterial balance in our bodies, fostering a healthy microbiome – the community of microorganisms living in our guts. A balanced microbiome not only promotes gut health but also promotes communication between the gut and the brain. Additionally, probiotics have been shown to enhance immune function, further underscoring their importance in overall health and well-being.

How our brains benefit from probiotics and a healthy gut

Understanding the brain-gut relationship is crucial for mental health, especially given the rising prevalence of mental health issues. Research on probiotic yogurt, for example, shows its substantial benefits in enhancing emotional responses in women, as well as managing anxiety, depression, and postpartum depression. Additionally, mood enhancements were observed in elderly individuals, suggesting that probiotics could be instrumental in supporting older adults as they face increased risks of depression, stress, and mood imbalances. 4

An in-depth review of current research on the brain-gut axis suggests that probiotics are a promising approach for tackling serious mental health conditions. They work by enhancing gut-brain communication  improving conditions such as Alzheimer’s, sleep disorders, schizophrenia, and autism. Specific bacterial strains, like Lactobacillus and Bifidobacterium, have been identified as particularly effective in reducing anxiety-like behaviors and boosting mood. 5

In a study involving healthy, older adults, a 12-week course of probiotics led to significant improvements in brain function and gut health. The probiotics notably reduced gut inflammation and increased the presence of beneficial bacteria. Participants who took probiotics experienced greater enhancements in stress reduction, mental flexibility, cognitive function, and overall brain health compared to those who received a placebo, underscoring the potential of probiotics in enhancing brain health. 6

The takeaway

At a time when innovative and more effective mental health treatments are in demand, probiotics are emerging as a promising option for boosting brain health. These beneficial bacteria, known for aiding digestion, may have a far-reaching impact on our mental well-being. They show promise in bolstering the brain-gut axis, potentially playing a significant role in enhancing mood, cognitive function, and overall mental health. As research continues to unfold, integrating probiotics into our diets and mental health treatments could be an exciting step for supporting both gut and brain health.

  1. Appleton J. (2018). The Gut-Brain Axis: Influence of Microbiota on Mood and Mental Health. Integrative medicine (Encinitas, Calif.), 17(4), 28–32.
  2. Probiotics: What You Need To Know | NCCIH. (n.d.). Retrieved March 26, 2024, from 
  3. Paraskevakos, G. (2022, June 15). International Probiotics Association. Probiotics and the Brain. 
  4. Ansari, F., Neshat, M., Pourjafar, H., Jafari, S. M., Samakkhah, S. A., & Mirzakhani, E. (2023). The role of probiotics and prebiotics in modulating of the gut-brain axis. Frontiers in nutrition, 10, 1173660. 
  5. Kim, C. S., Cha, L., Sim, M., Jung, S., Chun, W. Y., Baik, H. W., & Shin, D. M. (2021). Probiotic Supplementation Improves Cognitive Function and Mood with Changes in Gut Microbiota in Community-Dwelling Older Adults: A Randomized, Double-Blind, Placebo-Controlled, Multicenter Trial. The journals of gerontology. Series A, Biological sciences and medical sciences, 76(1), 32–40.