| Objective:To verify the effect of lactic acid bacteria（LAB）powder combined with calcium and zinc fortified milk on fatigue and immune status of soldiers engaged in tunnelling operation.Methods:According to the company structure,a total of 100 subjects of a tunnel construction unit were divided into two groups,50 in each group,and randomly given:（1）calcium and zinc fortified milk（227ml,2/day）（FM group）;（2）LAB(3×1010 CFU,2/day)+calcium and zinc fortified milk（227ml,2/day）（LAFM group）.Interventions were taken orally with breakfast and dinner.The data of basic information,dietary survey,subjective fatigue assessment,the human body composition analysis and"lift heel movement"muscle oxygen saturation,heart rate were collected and blood samples were taken before intervention.Blood routine,blood biochemical and C3,C4,Ig A,Ig G,interleukin,CD4,etc were detected by blood samples.After 12 weeks of continuous intervention,the data of human body composition analysis,muscle oxygen saturation,heart rate and serum samples were collected again.Dietary survey and subjective fatigue assessment were performed every 4 weeks of follow-up.Then the outcome indexes of the two groups before and after intervention were analyzed.Results:A total of 93 subjects completed the experiment,including 45 in the FM group（control group）and 48 in the LAFM group（experimental group）.Before intervention（0wk）,there were no significant differences in baseline data such as height,weight,number of smokers or drinkers,length of physical exercise per week,blood routine and biochemical tests between the two groups（P>0.05）.Daily energy,protein,fat and carbohydrate intake between the two groups or each group before and after the intervention were also found no significant differences（P>0.05）.However,the daily intake of calcium and zinc increased significantly after intervention（P<0.05）.The results of body composition analysis showed that there were no significant differences in body fat percentage,water ratio and phase angle between the two groups or each group before and after intervention（P>0.05）.In terms of clinical reaction,the incidence of digestive tract symptoms in the LAFM group was significantly lower than that in the control group at the end of the 12th week（P<0.05）.In terms of immune indexes,C3,Ig A,IL-10 and CD4 were all increased,while CRP was decreased in both groups at the end of the12th week（P<0.05）,but the increase in C3,Ig A and IL-10 in LAFM group was more significant（P<0.05）.The physical fatigue and total fatigue scores of LAFM group at the end of 4th,8th and 12th weeks were significantly lower than those before the intervention（P<0.05）,but the mental fatigue scores of the two groups did not change significantly at any follow-up stage（P>0.05）.The monitoring of muscle oxygen saturation during heel lifting exercise showed that the curve of muscle oxygen saturation presented a change of“descending—platform—recovery”.At the end of 12th week,the muscle oxygen saturation in both groups at the beginning of heel lifting（1s）was higher than that at 0wk（P<0.05）.The average muscle oxygen saturation in LAFM group at the“platform stage”was higher than that before intervention,but the difference was not significant（P>0.05）.Real-time heart rate monitoring during the heel lifting exercise showed that the heart rates of LAFM group at 12wk in the"platform stage"（21s,41s,61s）were significantly lower than that at 0wk（P<0.05）,but there were no significant differences at other time points（P>0.05）.Conclusion:Consume LAB combined with calcium and zinc fortified milk can supplement calcium and zinc lacking in the diet of soldiers working in the tunnel and alleviate the physical fatigue.It also plays a certain role in immunity enhancement.Its mechanism may be that LAB can promote calcium zinc material absorption,improve the body’s ability to adapt to exercise stress,anti-inflammatory and opsono-phagocytosis effects by regulating intestinal flora. |
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