Impact of fermented milk on human health: Cholesterol‐lowering and immunomodulatory properties of fermented milk

Abstract

ABSTRACTIn this review, we focus on the cholesterol‐lowering activity of Lactobacillus gasseri, the immunomodulatory function of casein phosphopeptides (CPPs) and lactic acid bacteria as starters for fermented milk, and the probability and difficulty of creating immunomodulatory fermented milk as a ‘food for specified health use’. Among the starter bacteria used for the preparation of fermented milk, L. gasseri SBT0270 could exert a hypocholesterolemic effect in rats fed a diet high in cholesterol through deconjugation of bile salts. On the other hand, CPPs, having a tripeptide sequence consisting of two phosphoserine residues at N‐ and C‐terminal positions, stimulated lymphocyte proliferation and IgA formation via the increase of interleukin‐5 and interleukin‐6 produced by type 2 helper T cells. The oral ingestion of CPPs enhanced the level of antigen‐specific and total intestinal IgA. Moreover, one strain of bifidobacteria (Bifidobacterium breve YIT4064) and one strain of Lactobacilli (Lactobacillus casei strain Shirota), used as a starter for fermented milk, activated the humoral and cellular immune system, respectively, and prevented various diseases. It is important to elucidate what components modulate and what mechanisms are responsible for the physiological function of fermented milk in order for it to be accepted as a ‘food for specified health use’ claiming immunomodulatory activity.