Reducing the risk of infection in the elderly by dietary intake of yoghurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1

Abstract

Immune senescence potentially leads to an increased risk of infections. It is desirable to augment the immune system and protect against infections by daily consumption of immunostimulatory food. The present study evaluated whether the intake of yoghurt fermented with Lactobacillus delbrueckii ssp. bulgaricus (L. bulgaricus) OLL1073R-1 has an effect on resistance to the common cold. We conducted two independent studies, in which fifty-seven (median age 745 years) and eighty-five healthy elderly individuals (median age 677 years) were participants. In each study, the subjects were divided into two groups based on age and sex and instructed to eat 90g yoghurt or drink 100ml milk once per d over an 8- or 12-week period. A meta-analysis of the results of these two independent studies showed the risk of catching the common cold was about 26 times lower (OR 039; P=0019) in the yoghurt group than in the milk group and the increase of natural killer cell activity was significantly higher in the yoghurt group than in the milk group (P=0028). In addition, the quality of life score for the eye/nose/throat system after intake was significantly higher in the yoghurt group than in the milk group and the improvement of the score was correlated with the promotion of natural killer cell activity. In conclusion, consumption of yoghurt fermented with L. bulgaricus OLL1073R-1 augmented natural killer cell activity and reduced the risk of catching the common cold in elderly individuals. © The Authors 2010.