The effect of fermented milk containing<i>lactobacillus casei</i>on the immune response to exercise

Abstract

There is evidence that exhaustive exercise produces depression of the immune system, especially on the number and activity of Natural killer (NK) cells. On the other hand, fermented milk has been shown to moderate the immune response by inducing NK activity. The present work was carried out to determine if a Lactobacillus casei (LC) fermented milk supplemented diet would provide protection of the immune system against an exercise induced immune system depression of NK cells. Twenty‐five athletes were selected out of 94 for their significant decrease in NK cell concentration compared with a normal basal concentration in plasma 2 h after an exercise stress test. Subjects ingested a daily fermented milk diet with LC for one month and a standard milk diet also for one month. After each phase of dieting, a subject was investigated before, 5 min and 2 h after an exercise stress test, testing for NK cells and IL‐1β IL‐6, IL‐2, IFNγ, IgA, IgM, IgG, NK cells, CD8, CD4, CD3 and sIL‐2 receptor. A significant smaller decrease of NK cell concentration after 2 h was found in the fermented milk feeding phase vs. the standard milk period.