Effects of Probiotic Supplementation on Immune Response in Soldiers: A Randomized, Double-Blinded, Placebo-Controlled Trial

Background: Athletic soldiers undergo strenuous and high-endurance training to prepare for competition. Stress and deprivation of proper nutrition can weaken the immune system in athletic soldiers. Therefore, enhancing the immune system function in addition to enhancing the performance of athletic soldiers can lead to a reduction in health costs for the military. Objectives: In this study, the effects of probiotic supplementation on the immune response of soldiers were assessed. Methods: In a randomized, double-blinded, placebo-controlled trial, 42 athletic soldiers were randomly divided into two groups of 21 members. Participants in the probiotic group daily received one glass of fruit juice containing Bacillus coagulans (2 × 109 CFU/g). The control group consumed the placebo at the same time. At the beginning and end of the study, as well as at specific times, IgA, CD4, lactate, and urea were measured in blood samples of all participants. Results: Probiotic supplementation increased the concentration of IgA (+115.7 ± 28.3 vs. -108.3 ± 25.7 mg/dL, P < 0.001) and CD4 levels (+129.1 ± 42.6 vs. -54.5 ± 114.6 cells/µL, P < 0.001) after three months in the test group. In addition, a significant decrease was seen in serum lactate (-5.7 ± 10.1 vs. +10.1 ± 7.4. mg/L, P < 0.001) and urea (-9.9 ± 6.7 vs. +2.3 ± 5.6 mg/dL, P < 0.001) concentrations following probiotic supplementation compared to the placebo. Conclusions: Probiotic consumption for 12 weeks has a positive effect on the immune response of soldiers.