Assistant Health Editor
Image by Ana Luz Crespi / Stocksy
October 20, 2025
Anxiety is on the rise, affecting nearly 60 million adults in the U.S. and nearly a billion people worldwide. While medications and therapy remain the main treatments, an unexpected player in mental health care is emerging: gut bacteria.
A study published in EMBO Molecular Medicine suggests that these microscopic organisms may have a direct impact on brain function – particularly anxiety levels – by regulating neuronal activity in a key fear-processing area of ​​the brain.
The experiment: how gut bacteria influence anxiety
Researchers from Duke-NUS Medical School and the National Neuroscience Institute of Singapore conducted a preclinical study in mice to investigate the connection between the gut and the brain. They divided the mice into two groups:
- Normal mice: These mice had a typical gut microbiome.
- Germ-free mice: These mice were raised in completely sterile conditions and had no intestinal bacteria.
The results were striking: the germ-free mice exhibited significantly more anxious behavior than their normal counterparts.
When placed in an open field test – a large box with both closed and open areas – the germ-free mice preferred to hide around the edges rather than explore. In an elevated zero maze test, they spent less time in open sections, further confirming their increased anxiety.
But behavior was just the beginning. The researchers examined the brains of the mice and discovered that the basolateral amygdala– a region responsible for processing fear and anxiety – was hyperactive in germ-free mice.
Their brain cells fire excessively due to reduced SK2 channels, which normally act as brakes on neuronal excitability.
The key to a calmer brain
To see whether intestinal bacteria can restore the balance, the researchers introduced indolea compound naturally produced by intestinal microbes, in the diet of the germ-free mice.
Remarkable enough, this simple addition reversed the brain’s hyperactivity and reduced their anxiety-related behavior. The treated mice became more exploratory and showed activity patterns similar to those of normal mice.
This suggests that gut bacteria play an essential role in regulating anxiety by producing biochemical signals that influence brain function. In other words, gut microbes can act as natural mood stabilizers.
A potential breakthrough in mental health care
This study provides strong evidence that the gut microbiome is directly linked to anxiety-related behavior.
Although this is still early-stage research (and in this case done on animals), the findings open the door possible new treatments for anxiety disorders in humans-medicines that do not rely solely on traditional medicine, but instead focus on gut health.
Dietary interventions for more support
Probiotics (live beneficial bacteria):
Certain probiotics, especially Lactobacillus And Bifidobacterium tensions – can help reduce stress, anxiety and depression.
Prebiotics (food for intestinal bacteria):
Prebiotics, such as dietary fiber and galactooligosaccharides (GOS), can promote the growth of beneficial bacteria.
One study found that GOS supplementation helped reduce anxiety symptoms3 in healthy women by increasing Bifidobacterium levels.
Synbiotics (probiotics + prebiotics):
Combining probiotics and prebiotics can provide even greater benefits.
Fermented dairy products:
Yogurt, kefir and other fermented dairy products naturally contain probiotics.
Herbs With Mental Health Benefits:
Certain herbs contain bioactive substances that can have a positive influence on the gut-brain axis.
Fruits and vegetables:
The takeaway
Your gut microbiome isn’t just about digestion; it plays a powerful role in brain function and mental health. Research shows that gut dysbiosis is related to this anxiety, depression and bipolar disorderbut dietary choices can help rebalance the microbiome.
By including probiotics, prebiotics, fermented foods, and anti-inflammatory herbs in your diet, you can naturally support both gut and brain health.
While we still have a lot to learn about the gut-brain axis, one thing is clear: what you eat doesn’t just affect your body; it also shapes your mind.
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