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Over the years, the Gut-Brain Axis (GBA) has gained popularity in research and amongst professionals due to compelling scientific evidence indicating that the gut and brain are closely connected, and that this link can affect mood, behavior, and overall mental health. This concept, which was initially introduced by William Beaumont in the 1840s, has created a shift in society’s attitude towards the importance of diet, stress, and lifestyle on mental wellbeing. As a result of this, interest has also grown in probiotics, which are live microorganisms that improve or restore the microbiota in the gut and, therefore, provide health benefits when consumed, and fermented foods as natural agents in the prevention and management of mental health conditions, such as anxiety and depression.
THE ROLE OF THE GUT MICROBIOME IN MENTAL HEALTH
In order to understand how probiotics and fermented foods impact mental wellbeing, it is essential to explore the key player in this system: the gut microbiome. This complex ecosystem is made up of trillions of microorganisms (e.g., bacteria, viruses), which produce neurotransmitters, such as serotonin and dopamine. In fact, around 90% of serotonin (a key neurotransmitter involved in mood regulation) is produced in the gut. When the microbiome is properly balanced, it positively impacts digestion, immune function, and our psychological well being. Conversely, when there is a disruption in this balance, known as dysbiosis, it can contribute to the development of various mental health disorders.
PROBIOTICS, FERMENTED FOODS, AND THEIR PSYCHOBIOTIC POTENTIAL
These discoveries regarding our understanding of the gut-brain connection have also sparked interest in psychobiotics as another potential player in this relationship. When these live microorganisms are ingested in adequate amounts, they interact with the gut microbiota and result in mental health benefits. Such positive effects are thought to arise from:
- The production of neurotransmitters (e.g., serotonin, GABA);
- Modulation of the hypothalamic-pituitary-adrenal (HPA) axis, which plays a role in controlling our reactions to stress;
- Reduction of systemic inflammation which reduces the risks of developing certain diseases (e.g., cardiovascular disease, cancer, diabetes).
In addition, several studies have explored the potential of specific probiotic strains in alleviating symptoms of depression and anxiety. For instance, a combination of “lactobacillus helveticus” and “bifidobacterium longum” have shown to be efficacious in reducing cortisol levels and psychological distress. These strains are commonly found in fermented dairy products, for example.
Moreover, fermented foods, rich in naturally occurring probiotics, have also been studied for their mental health benefits. Research shows that the regular consumption of products, such as yoghurt, kefir, sauerkraut, kimchi, and kombucha, has been linked with improved moods and reduced symptoms of anxiety. Another study suggested that probiotic food consumption might have beneficial effects on depression, particularly in men.
SUPPLEMENTS AS A BETTER ALTERNATIVE?
Modern nutritional science has directed its focus on probiotic supplements as a more targeted alternative to fermented foods. These supplements often contain specific strains in standardized doses, which could potentially offer a more consistent effect. As a result, they have become popular amongst individuals seeking to improve their mental health by focusing on and taking care of their gut.
However, not all probiotics have the same effects. In fact, most supplements contain a few strains, and since benefits are very strain-specific they may not apply universally. This means that an individual’s unique microbiota composition may not respond well to the strains present in a supplement. Moreover, people may sometimes take probiotics without medical need, which can create gut microbial imbalances, and the overuse of probiotics may even, in rare cases, cause infections or bacteremia (presence of bacteria in the bloodstream).
Overall, while probiotic supplements offer a lot of potential, the consumption of fermented foods provide additional nutrients that enhance microbiota diversity and function.
POTENTIAL RISKS
Some fermented foods, such as aged cheese and sauerkraut, can contain high levels of histamine, a compound involved in immune responses. People with histamine intolerances may experience headaches, digestive issues, skin rashes, and nasal congestion. Furthermore, foods like kimchi, soy sauce, and picked vegetables often have an elevated sodium content, and the regular consumption of such foods has been associated with high blood pressure and an increased risk of cardiovascular disease.
Unfortunately, the improper preparation and storage of these foods can also have dangerous effects. The risks are higher when the fermented food is prepared at home, where hygiene and temperature are not properly controlled. Additionally, the introduction of fermented foods too quickly or in large amounts can result in gas, bloating, and even cramping. This is especially common in individuals with IBS.
SO, WHERE DOES THIS LEAVE US?
With increase in evidence, society’s interest in fermented foods and probiotic supplementation is understandable. Their consumption may naturally support mental well-being by enriching gut microbial diversity and reducing systemic inflammation.
However, it is also important to understand that gut health, while important, is just one piece of the puzzle. Apart from having a diet focused on the consumption of fiber, probiotics, prebiotics, and fermented foods, it is also equally as important to prioritize regular exercise, sleep, and utilize stress management strategies.
Finally, while they are not a cure, fermented foods and probiotics can serve as valuable additions to the traditional mental health treatment, especially when they are personalized to individual needs.
Sara Janković
sara.jankovic01@icatt.it
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