A study was conducted in 57 healthy seniors (69–80 years old) living in Funagatamachi, Yamagata Prefecture, and 85 healthy seniors (59–84 years old) living in Aritacho, Saga Prefecture, in order to investigate the effects of lactic acid bacteria on the immune system. Each of these regional subject pools was divided into two groups. One group consumed 90 g of yogurt containing 1073R-1 lactic acid bacteria per day. The other group consumed 100 ml of milk per day. The subjects in Funagatamachi and Aritacho were kept on this dietary regimen for 8 and 12 weeks, respectively, then changes in their physical conditions and immunity were compared. For both regions, the groups consuming yogurt containing 1073R-1 lactic acid bacteria had a significant*1 increase in the ability to produce T cells, which tends to decline with age. Furthermore, in the groups consuming the yogurt in both regions, subjects with low NK activity before the consumption experienced a significant increase in NK activity. In addition, the risk of catching the common cold was reduced in the yogurt-consuming groups. If the risk of catching the common cold in the milk-consuming group is 1, the risks in the groups consuming yogurt containing 1073R-1 lactic acid bacteria in Aritacho and in Funagatamachi were 0.44 and 0.29, respectively. With these two risks combined for analysis, the weighted average risk is 0.39, indicating a significant reduction in the risk of catching the common cold.
In addition, when adaptive immunity was evaluated in Aritacho, it was confirmed that T cells, which serve to suppress the activities of specific viruses and bacteria, were activated by the consumption of the yogurt.
*This means that the experiment was statistically proven to be effective. As it is common to apply p<0.05 as the level of significance (i.e., less than 5% chance of sampling data 100 times and finding different results), this level was used in this study.
Yogurt containing 1073R-1 lactic acid bacteria enhanced NK activity and reduced the risk of catching the common cold.

*Meta-analysis was performed by the Mantel-Haenszel method after consolidating study data from Aritacho and Funagatamachi.
*Analysis of the study data collected in Aritacho and Funagatamachi was performed by Fisher’s test.


(Source: Makino S, et al. Br J Nutr. 2010;104(7):998-1006.)