Enhancement of natural immune function by dietary consumption of Bifidobacterium lactis (HN019)

Objective: To determine the effects of dietary consumption of Bifidobacteri um lactis (strain HN019, DR10(TM)) on natural immunity. Design: A randomized, double blind, placebo-controlled clinical trial. Sett ing:: Janeway Medical Centre, Memorial University, St Johns, Newfoundland. Subjects: Twenty-five healthy elderly volunteers (median age 69 y; range 60 -83 y). Interventions: Twelve control subjects consumed 180 mi low-fat/low-lactose milk twice daily for a period of 6 weeks: 13 test subjects consumed milk su pplemented with 1.5 x 10(11) colony-forming units of B. lactis twice daily. Indices of natural immunity, including interferon production, phagocytic c apacity and phagocyte-mediated bactericidal activity, were determined via p eripheral blood at 0, 3, 6 and 12 weeks post-trial commencement. Results: Subjects who consumed milk containing B. lactis for 6 weeks produc ed significantly enhanced levels of interferon-alpha, upon stimulation of t heir peripheral blood mononuclear cells in culture, in comparison to the pl acebo control group who received milk alone. There were also significant in creases in polymorphonuclear cell phagocytic capacity among test group subj ects, following consumption of milk supplemented with B. lactis, while indi viduals who consumed B. lactis-supplemented milk or milk alone showed enhan ced phagocyte-mediated bactericidal activity. Conclusions: The results demonstrate that dietary consumption of B. lactis HN019 can enhance natural immunity in healthy elderly subjects, and that a relatively short-term dietary regime (6 weeks) is sufficient to impart meas urable improvements in immunity that may offer significant health benefits to consumers.