Around the world, fermentation of foods has been adopted over many generations, primarily due to their commercial significance with enriched flavors and high-profile nutrients. The increasing application of fermented foods is further promoted by recent evidence on their health benefits, beyond the traditionally recognized effects on the digestive system. With recent advances in the understanding of gut-brain interactions, there have also been reports suggesting the fermented food’s efficacy, particularly for cognitive function improvements. These results are strengthened by the proposed biological effects of fermented foods, including neuroprotection against neurotoxicity and reactive oxygen species. This paper reviews the beneficial health effects of fermented foods with particular emphasis on cognitive enhancement and neuroprotective effects. With an extensive review of fermented foods and their potential cognitive benefits, this paper may promote commercially feasible applications of fermented foods as natural remedies to cognitive problems.
As the mechanisms underlying the beneficial effects of fermented foods are becoming more visible with accumulating results from clinical and animal studies, fermented foods are gaining popularity among consumers for their possible therapeutic and high marketing value. To our knowledge, this paper is the first research to conduct an extensive review on fermented foods and their cognitive enhancing effects, so to be used as a reference when studying the relevance of gut microbiota and fermented foods to brain functionality. Partly due to the paucity of clinical trials in humans using fermented functional foods, quantitative synthesis of these trial results could not be carried out. As more studies are published in the future, it would be possible to conduct a meta-analysis that may be helpful in confirming the beneficial effects of fermented functional foods.