Your gut and brain are in constant communication, so what you eat can have a massive impact on how you feel, and vice versa. In recent years, research has focused on the association between food-derived probiotics and cognitive performance, but a new study published in EMBO Molecular Medicine found that probiotic-packed fermented foods may even ease anxiety and depression.

The study examined the connection between gut bacteria and mental health, suggesting that certain probiotic strains found in fermented foods may positively impact anxiety and depression symptoms by reducing activity in the amygdala, a region of the brain responsible for processing fear and emotions. Researchers observed that mice consuming probiotics from fermented foods showed lower levels of stress and anxiety-like behaviors compared to those not receiving probiotics.

According to the report, the key mechanism behind this mood-boosting effect is how beneficial probiotics in the gut influence neurotransmitters such as gamma-aminobutyric acid (GABA), which significantly regulates mood and stress responses, says Harold Hong, MD, a psychiatrist and medical director at New Waters Recovery. “While promising, it’s important to remember that these findings were based on animal models, so more human studies are needed to fully understand how fermented foods directly affect mental health in people.”

So, should you fill your plate with fermented foods? Here’s what doctors suggest.

How fermented foods support mental health

Fermented foods support mental health by introducing beneficial bacteria, known as probiotics, into the gut, promoting a balanced microbiome (the collection of microbes, such as bacteria, fungi, viruses, and their genes, that naturally live on and in the body), says Zishan Khan, MD, a triple board-certified psychiatrist with Mindpath Health. “From there, these beneficial microbes can enhance gut barrier integrity, modulate the body’s immune responses, as well as produce neurotransmitter precursors (substances that help send signals between nerve cells), and all of these can ultimately impact the function of the brain and one’s mood.”

As for the exact mechanisms at play, probiotics reduce C-reactive protein and enhance the production of short-chain fatty acids, which Hong identifies as crucial markers for reducing inflammation, given that studies have linked depression and anxiety to an increased inflammatory response. So, because fermented foods possess anti-inflammatory properties, the hypothesis suggests that a stronger, more resilient gastrointestinal tract will be less susceptible to inflammation, ultimately impacting and enhancing gut-brain signaling, according to Meghan Garcia-Webb, MD, a triple board-certified physician and founder of Weight Medicine MD.  

The beneficial bacteria in fermented foods also produce compounds that support brain function, making it easier for your brain to manage stress and regulate emotions, according to Michael Genovese, MD, a neurologist and chief medical advisor at Ascendent New York. As a result, studies suggest that regular consumption of these foods can alleviate anxiety and depression, lower stress levels, and stabilize mood. 

That said, Hong emphasizes that fermented foods are not a substitute for therapy, medication, or other mental health treatments. “If someone is experiencing persistent anxiety, depression, or mood swings that interfere with daily life, they should consult a doctor or mental health professional.”

The gut-brain axis, explained 

The gut-brain axis is the communication highway between your gut (the gastrointestinal tract) and your brain (the central nervous system), Genovese says. “The two are connected through nerves, hormones, and immune signals, allowing them to influence each other, and if your gut microbiome is out of balance—meaning you have too many harmful bacteria or not enough beneficial ones—it can lead to inflammation and disruptions in brain function, which may contribute to anxiety, depression, and brain fog.”

In other words, your brain and gut maintain a constant feedback loop to ensure your body receives the essential nutrients it needs to thrive, as Genovese explains. Scientists are still investigating the precise workings of the gut-brain axis, but research suggests an undeniable link between changes in gut bacteria and mental well-being.

How to reap the mental health benefits of fermented food

Not all fermented foods are created equal when it comes to supporting your mental health. “The key is choosing fermented foods with ‘live and active cultures’ since pasteurized products do not offer the same benefits,” Genovese says. This is because pasteurization kills the live probiotics that make these foods beneficial, he explains. It’s also worth noting that fermented alcoholic beverages like beer and wine do not offer the same probiotic effects. 

Here’s a grocery shopping cheat sheet:

• Yogurt and Kefir: Yogurt and kefir contain Lactobacillus and Bifidobacterium, probiotic strains linked to reduced anxiety and depression symptoms, making both a worthy addition to your diet, Genovese says. 
• Kimchi and Sauerkraut: If you’re craving tangy spice, Khan says kimchi and sauerkraut are gut health superstars since they contain lactic acid and prebiotic fiber that feed beneficial bacteria. 
• Miso and Tempeh: Fermented soybean products like miso and tempeh are great additions to your diet since they both provide brain-boosting probiotics and amino acids, Khan says. 

Just be mindful that some fermented foods can contain high levels of sodium and sugar, which may offset potential health benefits. Both of these ingredients can disrupt the gut microbiome and might contribute to inflammation or an imbalance of beneficial bacteria when consumed in excess, Khan says. 

As for how much fermented food to eat, there is no standardized recommendation. “Individual responses can vary based on factors like gut microbiota composition and overall diet, but in general, I always advise patients to incorporate fermented foods gradually and observe personal tolerance and effects,” Khan says. It may sound counterintuitive, but excessive consumption of fermented foods can lead to digestive discomfort, including gas and bloating, he adds. 

To get started, Genovese recommends adding at least one serving of fermented food to your daily diet. “A cup of yogurt or kefir, a few spoonfuls of sauerkraut or kimchi, or a small bowl of miso soup can introduce enough beneficial bacteria to support gut health,” he says. 

And be consistent with it. “Some people notice improved digestion and mood within a few weeks of consistently eating fermented foods, but more significant changes in gut microbiome diversity and mental health benefits may take a few months,” Genovese says. “The key is to stick with it long-term because consistent intake is more important than eating a large amount of fermented foods all at once.”