Have you been more irritable or in a worse mood lately? Do you feel more exhausted and discouraged for no apparent reason? Do you get angry easily over things you barely noticed before? Perhaps the culprit behind these mood swings is an unexpected player: your gut.
For a long time, neuroscientists scrutinized the brain trying to understand the keys to mental health, but today we know that the trillions of bacteria living in our digestive tract do much more than process food; they also send signals to the brain and, in part, shape our emotional state.
It’s Not All in Your Head: the Role of the Gut-brain Axis in Mood
The gut-brain axis is a bidirectional communication network that connects the enteric and central nervous systems. The enteric nervous system, colloquially known as our second brain, is composed of millions of nerve cells lining the gastrointestinal tract.
It not only regulates digestive functions but also maintains constant communication with the brain through nervous, hormonal, and immunological pathways. The trillions of bacteria that make up the gut microbiota also actively participate in this dialogue, producing substances capable of influencing neuronal activity and the release of neurotransmitters.
Through this complex network of signals, the enteric nervous system influences processes such as mood, attention, thought, stress response, and emotional stability. This means that a healthy and balanced gut promotes a stable mood and a clear mind.
Conversely, if your gut health suffers, your mental health is likely to suffer as well. It is no coincidence that around 90% of the body serotonin, known as the “happiness hormone,” is produced precisely in the gut, while only 1-2% is generated in the brain.
A recent study conducted at Taiwan National University reinforced the deep connection between the gut and emotions by finding that people with depression have lower microbial diversity and higher levels of pro-inflammatory species in their gastrointestinal system. Similarly, an experiment published in the journal Nature demonstrated that probiotic consumption improves mood, which is why these supplements are being tested to treat problems such as anxiety and depression, among others.
How Can You tell if Your Gut is Affecting Your Mood?
It’s important to clarify that not all emotional problems originate in the gut, nor do all digestive problems cause psychological disturbances. However, if you’ve started noticing some of these symptoms, you might want to pay closer attention to your diet.
1. Worsening Mood without a Clear Cause
If you’ve recently noticed you’re more irritable than usual, feel “sluggish,” or struggle to find the energy to get things done, the problem might be in your gut. If your gut microbiota is disrupted, it could affect the production of serotonin and dopamine, which will worsen your mood.
2. Feeling Anxious for no Specific Reason
Many people with gut problems describe a persistent feeling of anxiety, restlessness, or distress, even without a clear emotional trigger. This could be because an inflamed or irritated gut sends warning signals to the brain, generating a continuous sense of threat.
3. Difficulty Thinking Clearly
When there are inflammatory processes in the gut or imbalances in the gut microbiota that affect the production of neurotransmitters and, consequently, the brain’s energy metabolism, you might experience what’s known as brain fog. In other words, you’re likely to find it difficult to concentrate and think, as if you’re “foggy.”
4. Increased Emotional Sensitivity and Low Stress Tolerance
When there’s an underlying gut issue, you’re more likely to become emotionally overwhelmed. You might react more intensely, get frustrated more easily, and lose your temper over nothing. This is generally because persistent gut inflammation reduces the brain’s ability to regulate emotions effectively.
5. You Suffer from Digestive Problems
A key sign that might lead you to suspect your emotional problems could have a gut-related cause is the appearance of symptoms such as frequent bloating, excessive gas, recurring episodes of diarrhea or constipation, or overly heavy digestion.
How to Rebalance Your “Second Brain”?
Lifestyle habits have a significant impact on the gut-brain axis. The foods in your diet also nourish your gut microbiota, influencing both its composition and the metabolites it produces. Therefore, being mindful of what you put on your plate is taking care of your emotions.
Whole grains, fruits, and cruciferous vegetables like kale are beneficial. These foods are beneficial for gut flora. Including them in your diet throughout the day (oatmeal at breakfast, fruit between meals, and vegetables with main meals, for example) is a simple way to protect your digestive health and psychological well-being.
If you need additional digestion support, there are dietary supplements like Detox Nourish, formulated with prebiotics, digestive enzymes, and plant nutrients to promote healthy digestion and eliminate toxins. This could help you feel more balanced, lighter, more energetic, and in a better mood.
The good news is that the gut microbiota usually responds quite quickly. It generally changes within a few days in response to the diet, although you’ll need to be more patient and persistent to see the effect on your mood, as it’s a slower and more complex process that could take several days or even weeks.
Finally, it’s important to clarify that gut health doesn’t depend solely on what you eat. Other factors, such as chronic stress or lack of sleep, also influence the composition of the gut flora and can increase inflammation, while regular exercise helps restore balance.
Therefore, if you want to take care of your mental health and well-being, remember that the key lies in small habits: eating and sleeping well, keeping stress under control, and moving every day. When one of these factors fails, the gut-brain axis is affected, and your mental health suffers the consequences.
References:
Lin, S. K. et. Al. (2025) Dysbiosis and depression: A study of gut microbiota alterations and functional pathways in antidepressant-naïve mood disorder patients. Transl Psychiatry; 15: 290.
Johnson, K.& Steenbergen, L. (2025) Probiotics reduce negative mood over time: the value of daily self-reports in detecting effects. NPJ Mental Health Res; 4: 10.
Sasso, J. M. et. Al. (2023) Gut Microbiome-Brain Alliance: A Landscape View into Mental and Gastrointestinal Health and Disorders. ACS Chem Neurosci;14(10):1717-1763.
Bektaş A, Erdal H, Ulusoy M, Uzbay IT. (2020) Does Serotonin in the intestines make you happy? Turk J Gastroenterol;31(10):721-723.
Appleton J. (2018) The Gut-Brain Axis: Influence of Microbiota on Mood and Mental Health. Integr Med (Encinitas);17(4):28-32.
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