薬理と治療

Abstract

Objectives　In this study, we investigated the effects of Lacticaseibacillus paracasei K71（formerly designated as Lactobacillus paracasei: L. paracasei K71）intake on maintenance of physical condition and immune parameters in healthy subjects. Methods　In this randomized, double-blind, placebo-controlled, parallel-group trial, 30 subjects were randomly allocated to an L. paracasei K71 group and 29 to a placebo group, and ingested a test food containing 100 mg of L. paracasei K71 or a placebo food once daily for 8 weeks. The subjects answered a questionnaire about their subjective symptoms related to physical condition every day during the intake period. Immune parameters were also evaluated, before the intake and at the 4th and 8th week of intake. Results　The cumulative number of days with all subjective symptoms was significantly lower in the L. paracasei K71 group than in the placebo group, but there was no significant difference in immune parameters between the groups. Subgroup analysis revealed that IL-12 and NK activity were significantly higher in the L. paracasei K71 group in the subgroup with low NK activity, and NK activity was significantly higher in the L. paracasei K71 group in the subgroup over 30 years old at week 8 of intake. No adverse events due to the test food were observed during the test period. Conclusions　The results suggested that the continuous intake of L. paracasei K71 suppressed the cumulative number of days with subjective symptoms related to physical condition caused by viral infections, etc., by maintaining appropriate immune function. UMIN-CTR ID: UMIN000042485