Immunomodulatory Properties of Fermented Soy and Dairy Milks Prepared with Lactic Acid Bacteria

ABSTRACT:  Fermented soy and dairy milk preparations provide a means for delivering lactic acid bacteria and their fermentation products into the diet. Our aims were to test immunomodulatory bioactivity of fermented soy beverage (SB) and dairy milk blend (MB) preparations on human intestinal epithelial cells (IEC) and to determine the impact of freezing medium on culture survival prior to bioactivity analyses. Fermented SB and MB were prepared using pure or mixed cultures of  Streptococcus thermophilus  ST5,  Bifidobacterium longum  R0175, and  Lactobacillus helveticus  R0052. Immunomodulatory bioactivity was assessed by testing selected SB and MB ferments on tumor necrosis factor α (TNFα)-treated IEC and measuring effects on Interleukin-8 (IL-8) production. Impact of timing of ferment administration relative to this pro-inflammatory challenge was investigated. The most pronounced reductions in IEC IL-8 production were observed when IEC were treated with either SB or MB ferment preparations prior to TNFα challenge. These results indicate that freezing-stable MB and SB ferments prepared with selected strains can modulate IEC IL-8 production  in vitro , and suggest that yogurt-like fermented soy formulations could provide a functional food alternative to milk-based fermented products.