Can Immunoregulatory Lactic Acid Bacteria Be Used as Dietary Supplements to Limit Allergies?

Abstract

Studies in gnotobiotic animals have suggested that the intestinal bacterial flora may play an important role in priming the immune system during ontogeny to limit dysfunctional responses, including allergy. Prospective clinical studies have identified a higher incidence of allergy expression in early childhood among children who have low enteric populations of lactic acid bacteria (LAB), such as lactobacilli and bifidobacteria, further supporting a role for gut-colonizing bacteria in regulating immunological atopy. There is some evidence to suggest that supplementing the human diet with probiotic LAB might combat both allergy development and expression of atopy in allergy sufferers; however, definitive information, in the form of controlled intervention trials, remains scant. Recent immunological evidence has indicated that certain strains of LAB can stimulate the production of type I and II interferons and pro-interferon monokines (IL-12 and IL-18), following contact with the immune system; therefore, probiotic forms of immunoregulatory LAB could be used as dietary supplements to modify the gut microflora and provide pro-T helper cell 1 (Th1) STAT-activating signals sufficient to deviate the immune phenotype and correct the Th2-type bias which promotes allergy. This review outlines the clinical and laboratory evidence of a role for LAB in combating allergies, and attempts to explain this phenomenon in terms of our current understanding of immunoregulatory signals produced by gut-colonizing microbes.

Correlation between in vitro and in vivo immunomodulatory properties of lactic acid bacteria

“…This strain-specificity has already been described in other experimental models of colitis [28][29][30][31] . The variations we observed between different LAB strains in this respect cannot simply be explained by differences in persistence, especially when daily administrations maintain the level of bacteria in the gastro-intestinal tract.…”

Gut bacteria and health foods—the European perspective

“…Although the mechanism of action of probiotics in preventing allergy is only beginning to be elucidated, the effects are likely to be mediated by adhesion to intestinal mucus and mucosal surfaces Ouwehand et al, 2001) and generation of anti-inflammatory cytokines (Cross and Gill, 2001). It has been hypothesised that prevention of early atopic disease in children may reduce the risk of developing food allergy and asthma later in life.…”

Infant intestinal Enterococcus faecalis down-regulates infl ammatory responses in human intestinal cell lines

“…The role of gastrointestinal microflora, such as several strains of lactic acid bacteria (LAB) in priming the immune system during ontogeny to limit allergy and chronic inflammatory responses has been brought to attention in recent years [1,2] . Clinical and experimental studies have put forward that gastrointestinal microflora is essential for maintenance of intestinal homeostasis, and their influence may extend beyond the gut, modifying systemic immunity.…”