Effect of milk fortified with calcium and zinc on bone health,training fatigue and neurobehavioral function in soldiers

Objective To observe the changes of bone health indicators,fatigue index and neurobehavioral function in soldiers after drinking milk fortified with calcium and zinc. Methods A double-blinded,cluster-randomized effectiveness trial was conducted in 103 soldiers who were engaged in technical work and participated in physical training regularly.They were randomly assigned to observation group (n=55,consuming 2 packages 227 ml per package of milk fortified with 150 mg/100 g Ca and 1.2 mg/100 g Zn)and control group (n=48,regular milk per day,100 mg/100 g Ca,0.4 mg/100 g Zn) according to squad organizational system.After 3 months of continuous intervention,the data of blood specimens (blood routine,blood biochemistry,vitamin,osteocalcin),body composition,bone mineral density,fatigue and neurobehavioral function were collected and assessed. Results A total of 94 subjects completed the study (51 cases in observation group and 43 cases in control group),with a loss rate of 8.74%.After the intervention,the serum osteocalcin concentration in the two groups was higher than that before the intervention,and it increased more significantly in observation group (0.59±0.36) ng/ml vs (0.41±0.38) ng/ml,P=0.037.Bone mineral density increased in both groups after intervention,but there was no significant difference between the two groups before and after intervention (P>0.05).The bone quality of the two groups was improved when compared with before intervention,and the increase of observation group was significantly higher than that of control group (4.25±6.69 vs 2.03±3.21,P=0.042).The results of fatigue assessment showed that the total score of fatigue assessment decreased in observation group,while it increased in control group after intervention (4.25±3.12 vs 5.14±3.36,P=0.013).The correct score of digit symbol increased after intervention in two groups,and the increase was larger in observation group (7.41±9.53 vs 3.42±9.61,P<0.001).The average score of pursuit aiming increased after intervention in observation group,while it decreased after intervention in control group (9.23±24.60 vs-8.92±22.60,P<0.001). Conclusion Milk consumption daily can improve soldiers’ bone quality,while the milk fortified with calcium and zinc has more advantages in osteocalcin and bone quality,and plays a certain role in alleviating soldiers' training fatigue and improving their neurobehavioral function.