The Chinese researchers studied 205 volunteers over the age of 45. Subjects in the intervention group were orally administered 300 mL/d of yogurt supplemented with a probiotic strain, Lactobacillus paracasei N1115 (N1115), 3.6×107 CFU/mL for 12 weeks, while those in the control group retained their normal diet without any probiotic supplementation.
Probiotic leads to less infections
The authors found compared to the control group, the number of people diagnosed with an acute URTI and the number of URTI events significantly decreased in the intervention group: The risk of URTI was 55% of that in the control group.
The severity of the infection in both groups was the same, however, for those who did get an infection.
The authors said their results agreed with a previous study on the addition of L. delbrueckii ssp. bulgaricus OLL1073R-1 to yogurt, which recorded similar results. However, other studies on fermented dairy drinks with added L. casei DN-114 001 or Lactococcus lactis ssp. lactis JCM5805 yielded results with similar incidences of infections, but with reduced duration of the condition.
They said intake of yogurt containing N1115 could protect against the risk of acute URTI in the middle-aged and elderly, one of the underlying mechanisms of which might be that N1115 stimulated T-cell immunity.
However, they noted as the study was limited to a blank control trial, a better designed, placebo-controlled trial is needed to clearly clarify the immune effect of the strain N1115 in the future.
The study was supported by Shijiazhuang Junlebao Dairy Co. Ltd.
Yogurt supplemented with probiotics can protect the healthy elderly from respiratory infections: A randomized controlled open-label trial
Source: Clinical Interventions in Aging
Authors: Pu F, Guo Y, Li M, Zhu H, Wang S, Shen X, He M, Huang C, He F