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March 24th, 2025
ByDr. Joseph Mercola
Contributing writer forWake Up World
Fermented foods stand out as a potent intervention when it comes to influencing your mental health by impacting a symbiotic relationship inside the body, which is called the gut-brain axis. Here, the influx of probiotics influences your mental health, and your current mood subsequently influences your microbiome. While the symbiosis looks simple on paper, it’s a complex communication network, underscoring the importance of eating fermented foods regularly.
Understanding the Link Between Fermented Foods and Mental Health
Fermented foods are rich in beneficial probiotics and metabolites, which influence your gut microbiota composition and diversity. These foods have been well-studied, and researchers eventually discovered that the human body has a communication pathway between your gut and brain — the gut-brain axis.1
When you eat fermented foods, the probiotics and other bioactive compounds begin to influence the communication between your gut and brain. In particular, a fascinating aspects about them, is their ability to influence mood, and researchers attempted to quantify their benefits in one study.
Fermented Foods — A Practical Path to Attaining Mental Wellness
The paper, published in Neuroscience & Biobehavioral Reviews, found that fermented foods offer an affordable dietary intervention strategy to enhance your mental health by targeting the gut-brain axis.2But before diving in further, the researchers established the definition of the gut-brain axis in their research:
“The microbiota-gut-brain axis facilitates a constant bidirectional relay of information from the intestine via the enteric nervous system (ENS) and from the intestinal milieu consisting of microbial communities, microbial metabolites, gut associated lymphoid tissue (GALT), peripheral immune cells and cytokines to the brain and vice versa via the sympathetic/parasympathetic nervous system, neurotransmitters and the circulatory immune system.”
Using this definition as the foundation, the researchers noted that incorporating fermented foods into your diet introduces a diverse array of beneficial microorganisms, resulting in a balanced gut microbiome. Moreover, this approach is convenient and cost-effective compared to taking a supplement, especially for families coming from different socioeconomic backgrounds around the world, as it offers them a way to stay healthy without resorting to adding another layer of expense.3
The neuroactivity of fermented foods is achieved through the introduction of probiotics into the digestive tract during consumption, which interact with the gut-brain axis. Enhanced microbiota diversity ensures a more resilient and efficient gut environment, which directly impacts brain health and function.4
Research also shows probiotics modulate immune and nervous system pathways, as well as impact the hypothalamic-pituitary-adrenal (HPA) axis, which is crucial for stress regulation. Probiotics also influence hormone levels, such as the gut hormones GLP-1, which plays important roles in glucose homeostasis and satiety.5
Going back to the gut-brain axis, fermented foods influence pathways that relay information from the gut to the brain by altering neurotransmitters, neuroactive substances and neuromodulators. These compounds play vital roles in regulating mood, stress response and overall cognitive function. In turn, this helps maintain the human body a balanced state of mental health, reducing the risk of disorders such as anxiety and depression.6
Moreover, fermented foods contain metabolites that reduce the permeability of both the intestinal barrier and the blood-brain barrier.7A strong barrier prevents harmful substances from entering the bloodstream and reaching the brain, thereby protecting it from inflammation. This is a key factor in preventing neuroinflammation and promoting cognitive resilience.8
Other Effects of Fermented Food on Human Physiology
Fermented foods exert immunomodulatory effects by influencing the levels of circulating cytokines and other immune markers. These benefits help reduce systemic inflammation, which is often linked to various mental health issues. By supporting the immune system, fermented foods create a healthier body and mind.9
The study also points out that probiotics influence the production of hormones such as serotonin, neuropeptide-Y, GLP-1, ghrelin, peptide YY, motilin and somatostatin, which play significant roles in regulating appetite, mood and energy. This promotes metabolic health, which is closely linked to mental health.
That’s because a well-regulated metabolic system aids in maintaining stable energy levels and mood, thus preventing the onset of mood swings and symptoms of depression. Certain probiotic strains also lower stress levels, which is another benefit that promotes better mood and overall health.10
The study underscores that fermented foods influence neurotransmitter levels, including serotonin, which is a key player in mood regulation.11The slight boost in serotonin levels help enhance feelings of well-being and happiness, reducing the prevalence of mood disorders.
However, note that serotonin levels shouldn’t be always elevated. As noted in my article “Media Twists Findings of Study Linking High Serotonin to Dementia,” elevated serotonin levels will contribute to health issues such as:
- Fibrosis, including cardiac and pulmonary fibrosis
- Impaired thyroid function
- Reduced metabolism due to excessive glycolysis and high lactic acid production
- Reductive and then secondary oxidative stress
- Bizarre, recurring nightmares and post-traumatic stress disorder (PTSD)
Strategies to Nourishing Your Gut Microbiome
Are you eating enough fermented foods? If you’ve been feeling down lately, adding them into your diet will give your mood a nice boost. This strategy subsequently affects the microbiota-gut-brain axis that results in better overall mental health. To help you achieve this goal, here are some practical steps:
- Make your own fermented foods at home —Creating fermented foods at home ensures you receive fresh, potent probiotics. Homemade options like yogurt, kefir and sauerkraut contain a diverse array of beneficial bacteria essential for a healthy gut microbiome.
- Plus, making your own fermented foods is cost-effective and allows you to control the ingredients, avoiding unnecessary additives, genetically modified ingredients and refined sugars found in mass-produced probiotic goods.
- Avoid pasteurized commercial fermented foods —Commercially available fermented foods are often pasteurized to extend shelf life, which kills the live bacteria necessary for gut health. Instead, opt for traditionally fermented, unpasteurized products sourced from reputable businesses. But again, a better solution is preparing them yourself to maximize the health benefits.
- Incorporate various fermented foods into your diet —Diversity is key when it comes to fermented foods. Different types offer unique strains of probiotics that work synergistically to enhance your gut microbiome’s resilience.
- Include a range of options such as kimchi, natto, homemade yogurt and homemade fermented vegetables in your daily meals. Variety helps ensure a robust and balanced microbiome, which is crucial for optimal gut-brain communication.
- Maintain consistent consumption —Regularly consuming fermented foods is essential for sustaining a healthy gut microbiome and reaping long-term mental health benefits. That’s because the modern Western diet is filled with ingredients that consistently destroy the beneficial bacteria.12Therefore, reseeding your gut with probiotics is important.
Make it a habit to include fermented foods in your everyday diet, whether through meals or snacks. Consistency helps maintain gut microbiota diversity, reduces inflammation, and supports stable neurotransmitter levels, all of which contribute to improved mood and cognitive function.
Additional Strategies to Boost Your Mood
While fermented foods are certainly important, there are other strategies available to help boost your mood. One of my top recommendations is getting regular exercise. Not only is it free, it’s also easy to incorporate into your daily routine.
In a study13published in the British Journal of Medicine, researchers noted that exercise is better than antidepressants when it comes to improving mental health. In fact, according to their calculations, it’s 1.5 times more effective. As noted by lead author Ben Singh, Ph.D.:14
“Physical activity is known to help improve mental health. Yet despite the evidence, it has not been widely adopted as a first-choice treatment … Higher-intensity exercise had greater improvements for depression and anxiety, while longer durations had smaller effects when compared to short and mid-duration bursts.
We also found that all types of physical activity and exercise were beneficial, including aerobic exercise such as walking, resistance training, Pilates, and yoga. Importantly, the research shows that it doesn’t take much for exercise to make a positive change to your mental health.”
Aside from exercise, eating a healthier diet (in addition to fermented foods) will help boost your mood. I recommend adding more vitamin B-rich foods into your diet, as this nutrient plays a role in cognitive function. For example, a B1 deficiency causes irritability and emotional disturbance. On the other hand, a B3 deficiency has been linked to anxiety, aggression and depression.15Sources and References
This article was first published on Mercola.com and republished here with permission.
About the author:
Born and raised in the inner city of Chicago, IL, Dr. Joseph Mercola is an osteopathic physician trained in traditional and natural medicine. Board-certified in family medicine, Dr. Mercola served as the chairman of the family medicine department at St. Alexius Medical Center for five years and, in 2012, was granted fellowship status by the American College of Nutrition (ACN).
While in practice in the late 80s, Dr. Mercola realized the drugs he was prescribing to chronically ill patients were not working. By the early 90s, he began exploring the world of natural medicine and soon changed the way he practiced medicine.
In 1997, Dr. Mercola founded Mercola.com, which is now routinely among the top 10 health sites on the Internet. His passion is transforming the traditional medical paradigm in the United States. “The existing medical establishment is responsible for killing and permanently injuring millions of Americans…You want practical health solutions without the hype, and that’s what I offer.”
VisitMercola.comfor more information, or read Dr. Mercola’s full bio and resuméhere.
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