Fermented foods, microbiota, and mental health: ancient practice meets nutritional psychiatry

Abstract

"The purposeful application of fermentation in food and beverage preparation, as a means to provide palatability, nutritional value, preservative, and medicinal properties, is an ancient practice. Fermented foods and beverages continue to make a significant contribution to the overall patterns of traditional dietary practices. As our knowledge of the human microbiome increases, including its connection to mental health (for example, anxiety and depression), it is becoming increasingly clear that there are untold connections between our resident microbes and many aspects of physiology. Of relevance to this research are new findings concerning the ways in which fermentation alters dietary items pre-consumption, and in turn, the ways in which fermentation-enriched chemicals (for example, lactoferrin, bioactive peptides) and newly formed phytochemicals (for example, unique flavonoids) may act upon our own intestinal microbiota profile. Here, we argue that the consumption of fermented foods may be particularly relevant to the emerging research linking traditional dietary practices and positive mental health. The extent to which traditional dietary items may mitigate inflammation and oxidative stress may be controlled, at least to some degree, by microbiota. It is our contention that properly controlled fermentation may often amplify the specific nutrient and phytochemical content of foods, the ultimate value of which may associated with mental health; furthermore, we also argue that the microbes (for example, Lactobacillus and Bifidobacteria species) associated with fermented foods may also influence brain health via direct and indirect pathways."

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Multiple facets of intestinal permeability and epithelial handling of dietary antigens

Abstract

"The intestinal epithelium, the largest interface between the host and environment, regulates fluxes of ions and nutrients and limits host contact with the massive load of luminal antigens. Local protective and tolerogenic immune responses toward luminal content depend on antigen sampling by the gut epithelial layer. Whether, and how exaggerated, the entrance of antigenic macromolecules across the gut epithelium might initiate and/or perpetuate chronic inflammation as well as the respective contribution of paracellular and transcellular permeability remains a matter of debate. To this extent, experimental studies involving the in vivo assessment of intestinal permeability using small inert molecules do not necessarily correlate with the uptake of larger dietary antigens. This review analyzes both the structural and functional aspects of intestinal permeability with special emphasis on antigen handling in healthy and diseased states and consequences on local immune responses to food antigens."

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Regulation of Tight Junction Permeability by Intestinal Bacteria and Dietary Components

Abstract

"The human intestinal epithelium is formed by a single layer of epithelial cells that separates the intestinal lumen from the underlying lamina propria. The space between these cells is sealed by tight junctions (TJ), which regulate the permeability of the intestinal barrier. TJ are complex protein structures comprised of transmembrane proteins, which interact with the actin cytoskeleton via plaque proteins. Signaling pathways involved in the assembly, disassembly, and maintenance of TJ are controlled by a number of signaling molecules, such as protein kinase C, mitogen-activated protein kinases, myosin light chain kinase, and Rho GTPases. The intestinal barrier is a complex environment exposed to many dietary components and many commensal bacteria. Studies have shown that the intestinal bacteria target various intracellular pathways, change the expression and distribution of TJ proteins, and thereby regulate intestinal barrier function. The presence of some commensal and probiotic strains leads to an increase in TJ proteins at the cell boundaries and in some cases prevents or reverses the adverse effects of pathogens. Various dietary components are also known to regulate epithelial permeability by modifying expression and localization of TJ proteins."

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Effect of organic and conventional cropping systems on ascorbic acid, vitamin C, flavonoids, nitrate, and oxalate in 27 varieties of spinach (Spinacia oleracea L.).

Abstract

"This study was undertaken to compare the levels of ascorbic acid, vitamin C, flavonoids, nitrate, and oxalate in 27 spinach varieties grown in certified organic and conventional cropping systems. Liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-(ESI)MS/MS) of methanolic extracts of spinach demonstrated 17 flavonoids, including glucuronides and acylated di- and triglycosides of methylated and methylenedioxyderivatives of 6-oxygenated flavonoids. The mean levels of ascorbic acid and flavonoids were significantly (p < 0.001) higher in the organically grown [40.48 ± 6.16 and 2.83 ± 0.03 mg/kg of fresh weight (FW)] spinach compared to the conventionally grown spinach (25.75 ± 6.12 and 2.27 ± 0.02 mg/kg of FW). Conversely, the mean levels of nitrate were significantly (p < 0.001) higher in the conventionally grown spinach compared to the organically grown spinach. No significant effects were observed in the oxalate content of spinach from either production system. The levels of nitrate correlated negatively with those of ascorbic acid, vitamin C, and total flavonoids and showed a positive correlation with the oxalate content. These results suggest that organic cropping systems result in spinach with lower levels of nitrates and higher levels of flavonoids and ascorbic acid."

http://www.ncbi.nlm.nih.gov/pubmed/22393895

 

See? Not only do you avoid pesticides by buying organic, you are buying more nutritious food!