Abstract
To elucidate the effect of fermented milk containing Lactobacillus johnsonii La1 on human blood phagocytic activity, a double-blind placebo controlled cross-over trial was conducted. Twenty-seven healthy Japanese volunteers were randomly divided into 2 groups, and either of test fermented milk containing L. johnsonii La1 (1x109 cfu /120 g) or placebo fermented milk without L. johnsonii La1 was administered daily for 21 days. At the end of the first period, blood phagocytic activity in the subjects administered test fermented milk increased significantly compared to that of before intake. Although phagocytic activity in the subjects administered placebo fermented milk also increased, the activity was low compared to that of the subjects administered test fermented milk. Blood phagocytic activities in the both groups were maintained at high levels after the 29 days wash-out period. At the end of the second period, phagocytic activity in the subjects administered test fermented milk was significantly higher than before intake. For confirmation of safety against excess dosage, 3 cups (360 g)/day of the test fermented milk was administered to 10 healthy persons for 14 days. Blood phagocytic activity significantly increased after administration of test fermented milk, and no adverse effects were observed in the medical check-up, blood and urine tests. These results suggest that ingestion of fermented milk containing L. johnsonii La1 is effective at reinforcing the natural immune system of humans without any safety concerns for excessive administration.
