Do Probiotics Improve Mental And Emotional Health?
There is a reason why you feel so good after that bowl of yogurt, Kefir or Miso Soup, bite of cheese or pickle or spoonful of Sauerkraut or Kimchi. Your brain really likes the probiotics in these fermented foods!
It has long been understood that healthy microbiota play a critical role in human development, particularly in areas such as immune development and metabolism. Although in its early stages, the emerging field of human microbiome research has indicated that gut microbiota may also play an important role in influencing brain development, behavior and mood in humans.
In a recent study, healthy female volunteers consumed a fermented milk product with a mixture of probiotics for 4 weeks. Results showed that probiotic consumption influenced brain activity in emotional centers in healthy individuals. Another study showed improved mood in healthy volunteers following 3-week consumption of a probiotic-containing milk drink. More recently, 30-day consumption of a probiotic mixture showed beneficial effects on anxiety and depressive measures and showed reduced levels of stress hormone, cortisol, in healthy volunteers.
Prebiotics, substances that can promote growth of beneficial commensal bacteria, can help too. A recent study that administered prebiotics to healthy volunteers resulted in lower cortisol levels at awakening and improved attention to positive stimuli compared to negative stimuli in an emotional categorization task and in an emotional recognition task.
Overall, these studies in healthy individuals provide clear evidence of a link between microbiota and emotional processing.
How Do Probiotics Influence The Brain?
The human intestine houses an astounding number and species of microorganisms, estimated at more than a trillion gut microbiota and composed of over a thousand species. Some are essential and beneficial, some are harmful and there are some otherwise benign ones that may turn harmful based on conditions encountered in the gut. In the absence or dysfunction of normal gut flora, a multitude of diseases may occur.
Studies have indicated that gut microbiota may be modulated with the use of probiotics. This makes them a great prospect for therapy in microbiota-associated diseases, including neuropsychological function, due to their beneficial impact on the following:
- Direct protection of the intestinal barrier
- Influence on local and systemic antioxidant status, reduction in lipid peroxidation
- Direct, microbial-produced neurochemical production – e.g. GABA
- Indirect influence on neurotransmitter/neuropeptide production
- Prevention of stress-induced alterations to overall intestinal microbiota
- Direct activation of neural pathways between gut and brain
- Limitation of inflammatory cytokine production
- Modulation of neurotrophic chemicals including brain-derived neurotrophic factor
- Limitation of carbohydrate malabsorption
- Improvement of nutritional status – e.g. omega-3 fatty acids, minerals, phytochemicals
- Limitation of small intestinal bacterial overgrowth
- Reduction of amine/uremic toxin burden
- Limitation of gastric/intestinal pathogens (e.g. Helicobacter pylori)
- Analgesic properties
- Probiotics and Prebiotics in Traditional Diets
Yogurt, Kefir, Souerkreut and Kimchi, Tempeh, Miso Soup and Soft Cheeses.
Asparagus, Jerusalem artichokes, bananas, oatmeal, red wine, honey, maple syrup and legumes.
Probiotics, either directly, or through their influence on other gut microbes, reduce levels of anxiety and depression, and provide benefits to cognition and behavior via gut-brain communication. Traditional fermented foods are a great source of probiotics and prebiotics – include them in your diet and rest assured, you will feel good!