• People with anxiety had differences in their gut microbiota compared to those without anxiety — Specifically, harmful bacteria that trigger inflammation were more abundant, while beneficial bacteria that regulate neurotransmitters and gut health were severely depleted.

• Proinflammatory cytokines interfere with neurotransmitter production — This imbalance was linked to increased production of proinflammatory cytokines, which are molecules that signal the immune system to mount a defense against a perceived threat. These inflammatory compounds were found to interfere with neurotransmitter production, disrupting serotonin and dopamine levels, both of which play a role in regulating mood and stress response.

• Gut dysbiosis impacts your body’s ability to handle stress — Individuals with higher anxiety levels had reduced levels of Faecalibacterium prausnitzii, a beneficial bacterial species known for its anti-inflammatory properties.

• This bacterium also produces butyrate — This short-chain fatty acid (SCFA) strengthens the gut barrier, reduces inflammation, and supports brain function.²

Without enough butyrate-producing bacteria, the gut lining becomes compromised, allowing harmful bacterial toxins to leak into the bloodstream, a condition known as “leaky gut.” This, in turn, increases systemic inflammation and amplifies anxiety symptoms.

• Probiotics affect your body’s ability to control stress — Another major discovery was the role of Lactobacillus and Bifidobacterium strains in regulating the hypothalamic-pituitary-adrenal (HPA) axis, which is the body’s stress-response system. The study found that individuals with lower levels of the mentioned probiotics exhibited a heightened cortisol response — a sign of an overactive stress system.

• Excess cortisol keeps the body in a prolonged state of stress — This makes it harder for you to relax, sleep, and manage emotions. Restoring these beneficial bacteria will help bring cortisol levels back to normal, reducing overall anxiety and improving resilience to stress.

• Your gut bacteria also affects your mood — Beyond bacterial composition, the researchers also examined how gut metabolites — compounds produced by gut bacteria — impact anxiety. One of the most notable findings was the reduced production of gamma-aminobutyric acid (GABA), a neurotransmitter responsible for calming the nervous system.

• GABA deficiency is strongly linked to anxiety disorders — It prevents the brain from shutting off excessive worry and stress signals and probiotics, particularly Lactobacillus rhamnosus, play a key role in producing GABA. The study found that individuals with anxiety had significantly lower levels of this species, theorizing that replenishing it will help restore a sense of calm and relaxation.

• Your diet is important in maintaining a balanced gut microbiome — Researchers noted that a fiber-rich diet, including prebiotic foods, raw grass fed dairy and nutritious spices like ginger feed beneficial bacteria, allowing them to thrive and produce anti-inflammatory compounds like butyrate, which helps protect against anxiety and stress-related disorders.

• Gut bacteria plays a role in brain inflammation — Individuals with anxiety had increased levels of Desulfovibrio, a bacterial strain known to produce endotoxins, which are harmful substances that trigger an immune response. These endotoxins cross the blood-brain barrier and activate microglia, the brain’s immune cells, leading to neuroinflammation. This type of inflammation has been linked to mood disorders, including depression and anxiety.³

• Participants with social anxiety had a significantly different gut microbiome composition — Notably, those with SAD exhibited a higher presence of certain bacterial strains linked to inflammation and neurotransmitter disruption, while beneficial bacteria were present in much lower amounts.

These differences were not subtle — specific bacterial populations showed a strong correlation with anxiety symptoms, indicating that gut health is be a key factor in the development or worsening of social anxiety.

• One of the most striking findings was the elevated levels of Anaeromassilibacillus — This lesser-known bacterial genus was significantly more abundant in those with SAD. Anaeromassilibacillus has been linked to inflammatory responses and metabolic disturbances, both of which contribute to heightened stress sensitivity.

• In contrast, the healthy control group had higher levels of Parasutterella excrementihominis — This beneficial bacterial species is known to support gut barrier integrity and reduce inflammation. The presence of these bacteria — or lack thereof — shows the power of microbial imbalances to influence brain chemistry and anxiety-related behaviors.

• Functional differences in the gut microbiome — Individuals with social anxiety had an overactive “aspartate degradation” pathway in their gut bacteria. This means their microbiome was breaking down the amino acid aspartate at a much higher rate compared to healthy individuals.

• Aspartate is essential for neurotransmitter production — It’s particularly important in the creation of glutamate, which plays a major role in brain function and mood regulation. When gut bacteria interfere with this process, it leads to disruptions in neurotransmitter balance, contributing to increased anxiety and emotional distress.

The implications of this are significant because the gut microbiome communicates with the brain through various pathways, including the production of neurotransmitters, immune system regulation, and the vagus nerve. When gut bacteria become imbalanced, it increases the risk of chronic inflammation and disrupts the production of key neurotransmitters like GABA.

• Interestingly, gut microbiome differences remained consistent — This was seen even after the researchers controlled for factors such as diet, exercise, and body mass index (BMI). This means that the microbial imbalances were not just the result of poor lifestyle habits but were directly associated with the presence of SAD itself.

This reinforces the hypothesis that treating gut health is a viable approach to managing anxiety, rather than relying solely on psychiatric medications or therapy.

• The connection between gut microbiota and inflammation — Chronic inflammation has long been associated with depression, and the study highlighted how an imbalanced gut microbiome directly fuels this process. Increased levels of proinflammatory cytokines were found in individuals with anxiety and depression.⁶

• Diet influences the diversity of your gut microbiota — The research also pointed to a dietary factor worsening the problem — processed and refined sugar diets disrupt the balance of gut bacteria. Western dietary patterns, which are abundant in processed foods and low in fiber, were shown to reduce beneficial bacterial species like Lactobacillus and Bifidobacterium, which support mental health.⁷

• The impact of SCFAs on overall gut and mental health — One noteworthy observation mentioned in the study involves SCFAs, such as butyrate, acetate and propionate. These compounds play a crucial role in reducing inflammation and maintaining the integrity of the gut barrier. Moreover, boosting the production of these SCFAs “reduces stress-induced depressive behaviors.”⁸

• Prebiotics nourish the beneficial bacteria already living in your gut — Consuming prebiotics like fructo-oligosaccharides (found in fruits and vegetables such as nectarines and scallions⁹) increased levels of beneficial bacteria and reduced inflammation.

These compounds were found to improve gut microbiota composition and enhance the production of SCFAs. Importantly, the study noted that combining prebiotics with probiotics — referred to as synbiotics — had the most substantial effects on reducing anxiety and depressive symptoms.¹⁰

• Bringing in probiotics from another person’s gut — Another intervention explored in the study was FMT. This procedure involves transferring stool from a healthy donor into the gut of a patient to restore microbial diversity.

While primarily used to treat severe gut infections, FMT has been shown to help improve mental health by reintroducing beneficial bacteria that regulate inflammation and neurotransmitter production.

Patients who received FMT from healthy donors experienced not only improved gut health but also reductions in anxiety and depressive symptoms. However, this approach is still being researched and is not yet widely available for mental health treatment.¹¹

1. Rebuild your gut microbiome with the right foods — What you eat directly impacts the bacteria in your gut. If your diet is full of ultraprocessed foods, sugars, and unhealthy fats, you are feeding harmful bacteria that promote inflammation and anxiety. To get back on the right track, switch to whole, natural foods that nourish beneficial gut bacteria, such as:

2. Introduce key probiotic strains to nourish your gut — As noted in the research, probiotics have been shown to reduce anxiety by improving neurotransmitter function and overall gut health. I recommend you eat probiotic-rich foods such as kimchi and kefir. If you’re not fond of fermented foods, a high-quality probiotic supplement with the following strains will help:

3. Reduce gut inflammation that fuels anxiety — Chronic inflammation in the gut is a major driver of anxiety. When your gut lining is weakened, inflammatory compounds leak into your bloodstream and disrupt brain function.

Reduce gut inflammation by minimizing your intake of vegetable oils, fried restaurant foods, and ultraprocessed products. To repair your gut lining, drink bone broth, which contains glutamine. Add turmeric and ginger to your diet as well — these are powerful anti-inflammatory agents that support gut health.

4. Support the gut-brain axis by boosting your SCFA production — Beneficial gut bacteria produce SCFAs, such as butyrate, which help maintain a strong gut barrier, and even reduce neuroinflammation.¹²

To encourage SCFA production, I recommend you eat whole foods that are high in fiber, such as fruits like berries and pears. Vegetables are also a good source, and it’s also a good strategy because it diversifies your nutrient intake. For a more in-depth explanation on how to do this properly, read “Butyrate — Fueling a Normal Gut Environment and Supporting Energy Production.”

5. Manage stress to protect your gut microbiome — Stress damages your gut bacteria and increases inflammation, worsening anxiety. So, I recommend you incorporate the following healthy habits because a healthy diet can only do so much to ward off the effects of stress: