Did you know that fermented foods may help improve cognitive performance and directly impact the enteroendocrine system? But how is this possible? They affect hormones such as ghrelin (hunger signal), neuropeptide-Y, serotonin, and glucagon-like peptide 1 (GLP-1)(stimulates insulin production). This is possible through a bidirectional communication network, called the microbiota-gut-brain axis, that links the nervous system to the digestive system. Microbes in the gut can produce molecules that can enter the bloodstream and circulate to the brain which also produces chemicals that circulate back to the gut. (Read more here.)
Looking at specific fermented food and their potential to modulate health and the gut-brain axis, tempeh has been demonstrated in zebrafish to result in upregulation of serotonin transport and synthesis genes. Human studies looking at fermented milk products and wine have shown serotonin increases in plasma and feces. This review has a nice breakdown of the major outcomes of multiple fermented food studies.
Another recent article from the University of Virginia School of Medicine (UVA) found that removal of two lactic acid bacteria (L. intestinalis and L. murinus) from a known microflora amplified stress responses in mice. Important in many fermented foods, Lactobacillus spp. are beneficial in improving mood disorders and maintaining interferon-gamma levels that regulate stress and depression responses.
More research is necessary to understand the relationship of fermented foods to cognitive performance. What are your thoughts on this research topic? How often do you eat fermented foods, and have you ever noticed improvement in mood when eating them?
Image Source: Living Nutrition