Dietary Correction of Stress- and Trauma-related Mental Disorders: Kefir as a Psychobiotic Agent

Abstract

Dietary correction of psychological disorders is an extensively developing area. Kefir is a popular dairy product that attracts attention due to its capability to correct mental disorders related to trauma and chronic stress, such as post-traumatic stress disorder and generalized anxiety disorder. This work aims to systematically analyze the neurobiological and molecular mechanisms, which the gut microbiota, in conjunction with metabolites from fermented foods such as kefir, modulates emotional and cognitive parameters. The authors' analysis shows that stress-induced dysregulation of the hypothalamic-pituitary-adrenal axis compromises the intestinal barrier, leading to systemic neuroinflammation. Kefir counteracts this process by strengthening tight junctions, reducing the translocation of pro-inflammatory lipopolysaccharides and food particles from the intestinal lumen into the bloodstream, particularly by producing short-chain fatty acids such as acetate, propionate, and butyrate. The paper demonstrates a direct link between kefir consumption and increased expression of brain-derived neurotrophic factor via short-chain fatty acids mediated epigenetic modulation and the production of the inhibitory neurotransmitter gamma-aminobutyric acid. We propose here the evidence-based recommendations for clinical practice, that a minimum kefir intervention duration of eight weeks is required for sustainable therapeutic effects. Due to its general psychobiotic properties realized through antiintflammatory, antioxidant, and neutropic effects, kefir may be a promising, safe, accessible, and inexpensive adjunct therapy to traditional psychotropic medications, calling for further large-scale randomized controlled trials.