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New Health Insights Series Coming Soon
Our team works behind the scenes to prepare new research and practical health strategies for our readers. While you prepare for what comes next, please take a look at one of the most read articles in our library below. See exactly what’s changing →
Anxiety, depression, epilepsy, and even Alzheimer’s disease all share surprising similarities. That’s because you have low levels of a calming brain chemical called GABA. GABA, short for gamma-aminobutyric acid, acts as the brain’s primary “brake pedal,” slowing down excessive firing and returning the nervous system to a calm, stable state.
When these neurotransmitters become out of balance, symptoms include racing thoughts, lack of sleep, panic attacks, memory problems, and even seizures. Many people think of GABA as a brain chemical that is only made in the brain. But more and more research is showing that the gut microbiome plays a powerful role in how much GABA the brain actually produces.
In fact, a study published in NPJ Science of Food found that probiotics, as well as certain types of prebiotics, increase GABA levels in the gut and, more importantly, in the brain.1 GABA is important because it not only helps you relax, but it also helps regulate everything from mood to cognition to immune response.
If your gut microbiome does not support sufficient GABA production, you may become trapped in patterns of chronic tension, emotional instability, or cognitive fog. Even though you are eating well and getting enough sleep, you may still feel like something is wrong.
The root cause may lie in your microbiome, and the solution may be as simple as restoring the correct bacterial balance. Let’s take a closer look at how this research uncovers the gut-brain connection that drives GABA production, and why it could change the way you approach mental health from the inside out.
Prebiotics Increase GABA in the Brain by Changing Gut Bacteria
In the NPJ Food Science study, researchers investigated whether fructooligosaccharides (FOS), a well-known prebiotic, and an enzyme derived from the fungus Aspergillus could increase levels of GABA and homocarnosine (compounds primarily found in the brain, made from GABA, which helps keep brain cells healthy and the mind sharp).2 Probiotics have been shown to increase GABA in the gut and brain, but researchers wanted to know if and how prebiotics could perform the same function.
• This study examined brain and gut outcomes in adolescent rats. Researchers fed adolescent mice FOS, Aspergillus lipase, or Aspergillus protease for four weeks. They then measured GABA and homocarnosine levels in the gut, blood, and brain. They also analyzed the gut microbiome to find out which bacterial changes could explain the changes in neurotransmitter levels.
• FOS and the enzyme increased GABA levels in the brain in several areas — All three treatments – FOS, lipase, and protease – increased GABA levels in the brain, particularly in the cortex and hippocampus, two regions associated with memory, stress, and emotional balance. FOS also increased GABA in the hypothalamus, a key regulator of hormonal and autonomic nervous system activity.
• Homocarnosine, a GABA-based brain peptide, was also increased. The researchers observed a significant increase in homocarnosine in the hippocampus of all treatment groups, along with higher GABA levels. Homocarnosine plays an important role in nerve function. Increases in both compounds indicate deeper changes in brain chemistry associated with gut microbial activity.
• GABA was not increased in the bloodstream, suggesting a non-blood-based communication pathway. Interestingly, neither treatment increased GABA in the blood. This suggests that GABA produced in the gut may transmit signals to the brain through other pathways, such as the vagus nerve or hormonal pathways, rather than circulating in the bloodstream.
Increased beneficial bacteria with GABA
After treatment, the gut microbiome shifted in measurable ways. FOS and enzymes increased beneficial species such as Parabacteroides, Akkermansia, Muribaculum and Hungatella. These specific bacteria showed a strong positive correlation with higher GABA and homocarnosine in the brain. They are now considered a possible “helper species” in this gut-brain communication network.
• Other bacterial strains also decreased. That’s a good thing. Bacteria negatively linked to GABA and homocarnosine, including Blautia, Roseburia, and Eubacterium coprostanoligenes, decreased in abundance following FOS and enzyme ingestion. These species are often associated with increased gut dysbiosis, which can interfere with healthy neurotransmitter production.
• FOS had the greatest impact on the intestinal environment. All three supplements increased GABA in the brain, but FOS triggered the most pronounced changes in gut microbiome composition and diversity. This significantly increased the relative abundance of Bacteroidota and Verrucomicrobiota, microbial phyla associated with metabolic health, and decreased Firmicutes, a group often associated with inflammation when imbalanced.
• Aspergillus enzymes also acted like prebiotics by reshaping the gut microbiome. Although not a traditional fiber, the fungal enzymes used in the study showed similar behavior to prebiotics. They probably help break down undigested macronutrients in the large intestine, releasing nutrients that feed GABA-supporting bacteria.
• Bacterial changes are directly linked to neurotransmitter levels. Using correlation analysis, the researchers found that certain bacterial populations, specifically Akkermansia, Parabacteroides, and Flavonifractor, were strongly associated with higher GABA and homocarnosine levels. Meanwhile, species such as Colidextribacter and Acetatifactor were tied to low levels. These patterns help pinpoint which microorganisms have supportive and inhibitory roles in GABA metabolism.
How to Heal Your Gut to Restore GABA Balance
If you feel like your mental energy is off-kilter (too connected during the day and too anxious at night), your GABA levels may be out of sync. And that imbalance often starts in the gut. When your microbiome is compromised, even “healthy” foods like prebiotics can make your symptoms worse. But once your gut is stable, the right prebiotics can increase GABA in your brain, a powerful tool for restoring calm and focus. The important thing is to know when and how to use it. Here are five steps to help you get there.
1. If your gut is inflamed, don’t jump on prebiotics — If you feel gassy, bloated, or irregular after eating, it’s likely that your intestinal lining is irritated and your microbiome is out of balance. Now is not the time to load up on garlic, onions, and chives. This feeds bacteria that ferments too quickly and increases harmful endotoxins, worsening symptoms. Instead, eat metabolically safe carbohydrates like white rice and fruit, which can nourish you without feeding the wrong bacteria.
2. Wait until symptoms have stabilized before adding fermentable carbohydrates — Most people get hooked on fiber thinking it’s always a good thing. However, when the intestinal barrier is damaged, even resistant starches and “gut-friendly” fibers do more harm than good. Once you have regular bowel movements without bloating, it’s a green light to start reintroducing prebiotics slowly and purposefully.
3. Support GABA with food-based prebiotics at the right time. Once your digestion is strong, start eating prebiotic foods that specifically support GABA-producing bacteria. These include FOS-rich choices like bananas, asparagus, garlic, and leeks. The goal is not to flood the system, but to gently balance it with the right species, such as Akkermansia. A quarter of a cooked leek or a few slices of ripe banana may be all you need to get started.
4. Boost your brain GABA with fermented foods and targeted supplements — Once microbial stability is achieved, start layering with direct GABA support. Fermented foods like kimchi, kefir, and soybean paste contain small but significant amounts of GABA. If you have high stress or poor sleep, consider a high-quality GABA supplement.
5. Use natural progesterone to amplify the calming effects of GABA — Natural progesterone enhances GABA signaling in the brain and has a direct calming effect on the nervous system. Unlike synthetic progestins, natural progesterone is a hormone that your body already recognizes and responds to.
FAQs about prebiotics and GABA
cue: How does the gut microbiome affect GABA levels in the brain?
no way: Gut bacteria play an important role in producing GABA, the brain’s main calming neurotransmitter. Certain beneficial microorganisms, such as Akkermansia and Parabacteroides, help increase GABA and its brain-related partner homocarnosine. When these microbes are supported with the right prebiotics, GABA levels rise in brain areas associated with memory, stress, and mood regulation, helping reduce anxiety, improve sleep, and support cognitive clarity.
cue: What are the best prebiotics to boost brain GABA?
no way: Fructooligosaccharides (FOS), found in foods such as garlic, onions, leeks, bananas, and asparagus, support GABA-producing microbes. Enzymes derived from the Aspergillus mold, especially proteases and lipases, act like prebiotics by rebuilding the gut microbiome and feeding the right bacteria without the fermentation that causes gas or bloating.
cue: Should I take prebiotics if my gut is inflamed or damaged?
no way: Not yet. If you feel bloated, constipated, or have loose stools, your gut may not be ready for foods high in prebiotics. In this condition, prebiotics become food for the wrong microorganisms and increase inflammation. It’s a good idea to start with metabolism-supporting carbohydrates, such as white rice and fruit, then slowly introduce prebiotics once digestion has stabilized.
cue: Besides prebiotics, what natural strategies can help increase GABA?
no way: Fermented foods such as kimchi, kefir, and soybean paste provide small amounts of GABA directly. The supplement provides more targeted support if your levels are depleted. Natural progesterone also enhances the calming effects of GABA in the brain, which helps reduce the feeling of feeling wired but tired that often occurs due to hormonal imbalances or chronic stress.
cue: What does homocarnosine do and why is it important?
no way: Homocarnosine is a brain-specific compound made from GABA and histidine. This helps protect neurons, stabilize brain chemistry, and support clear thinking. The same prebiotics that increase brain GABA also increase homocarnosine levels, making them doubly important for improving neurological health through the gut-brain axis.
