title: Immunoprotective effects of oral intake of heat-killed Lactobacillus pentosus strain b240 in elderly adults: a randomised, double-blind, placebo-controlled trial.
abstract: Oral intake of Lactobacillus pentosus strain b240 (b240) has been shown to enhance the secretion of salivary secretory IgA in elderly adults. However, its clinical benefits remain to be determined. We tested the hypothesis that b240 exerts a protective effect against the common cold in elderly adults. The design of the present study was a randomised, double-blind, placebo-controlled trial (RCT) with parallel three-group comparison. For this purpose, 300 eligible elderly adults were randomly allocated to one of three groups, namely a placebo, low-dose or high-dose b240 group. Participants in the low-dose and high-dose b240 groups were given tablets containing 2 × 10(9) or 2 × 10(10) cells, respectively, of heat-killed b240, while those in the placebo group were given tablets without b240. Each group consumed their respective tablets once daily for 20 weeks. The common cold was assessed on the basis of a diary. Change in quality of life was evaluated using the SF-36. Of the total participants, 280 completed the 20-week RCT. The accumulated incidence rate of the common cold was 47·3, 34·8 and 29·0 % for the placebo, low-dose b240 and high-dose b240 groups, respectively (P for trend = 0·012). Lower incidence rates were consistently observed throughout the experimental period in the b240 groups (log-rank test, P= 0·034). General health perception, as determined by the SF-36®, dose-dependently increased in the b240 groups ( P  <0·025). In conclusion, oral intake of b240 significantly reduced the incidence rate of the common cold in elderly adults, indicating that b240 might be useful in improving resistance against infection through mucosal immunity.
authors.affiliation: The Research Team for Social Participation and Community Health, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan. sshinkai@tmig.or.jp
authors.forename: Shoji
authors.initials: S
authors.lastname: Shinkai
authors.forename: Masamichi
authors.initials: M
authors.lastname: Toba
authors.forename: Takao
authors.initials: T
authors.lastname: Saito
authors.forename: Ikutaro
authors.initials: I
authors.lastname: Sato
authors.forename: Mina
authors.initials: M
authors.lastname: Tsubouchi
authors.forename: Kiyoto
authors.initials: K
authors.lastname: Taira
authors.forename: Keiji
authors.initials: K
authors.lastname: Kakumoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Inamatsu
authors.forename: Hiroto
authors.initials: H
authors.lastname: Yoshida
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Fujiwara
authors.forename: Taro
authors.initials: T
authors.lastname: Fukaya
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tateda
authors.forename: Keizo
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Kohda
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kohno
mesh_terms: D000284:Administration, Oral; D000368:Aged; D003139:Common Cold / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D018928:Immunity, Mucosal / Q000187:drug effects*; D007071:Immunoglobulin A, Secretory / Q000378:metabolism; D007155:Immunologic Factors / Q000627:therapeutic use*; D015994:Incidence; D007778:Lactobacillus; D008297:Male; D019936:Probiotics / Q000627:therapeutic use*; D013045:Species Specificity
chemical_list: D007071:Immunoglobulin A, Secretory; D007155:Immunologic Factors